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Sample records for aid output snr

  1. A Multiple Model SNR/RCS Likelihood Ratio Score for Radar-Based Feature-Aided Tracking

    DTIC Science & Technology

    2005-01-01

    A Multiple Model SNR /RCS Likelihood Ratio Score for Radar-Based Feature-Aided Tracking Benjamin J. Slocumb and Michael E. Klusman, III Numerica...based on statistical models for the signal-to-noise ( SNR ) and radar cross section (RCS) for use in narrowband radar tracking. The formulation requires...features ( SNR and RCS measurements from a narrowband radar) for augmenting the track score used in the data association problem. There are two main

  2. Perceptions of the Design of Voice Output Communication Aids

    ERIC Educational Resources Information Center

    Judge, Simon; Townend, Gillian

    2013-01-01

    Background: Voice output communication aids (VOCAs) are a key form of aided communication within the field of augmentative and alternative communication (AAC). In recent years, rapid developments in technology have resulted in an explosion of devices available commercially, yet little research has been conducted into what people who use VOCAs…

  3. Speech Intelligibility of Two Voice Output Communication Aids.

    ERIC Educational Resources Information Center

    Kannenberg, Patricia; And Others

    1988-01-01

    The intelligibility of two voice-output communication aids ("Personal Communicator" and "SpeechPAC'") was evaluated by presenting synthesized words and sentences to 20 listeners. Analysis of listener transcriptions revealed significantly higher intelligibility scores for the "Personal Communicator" compared to the…

  4. Program Aids In Printing FORTRAN-Coded Output

    NASA Technical Reports Server (NTRS)

    Akian, Richard A.

    1993-01-01

    FORPRINT computer program prints FORTRAN-coded output files on most non-Postscript printers with such extra features as control of fonts for Epson and Hewlett Packard printers. Rewrites data to printer and inserts correct printer-control codes. Alternative uses include ability to separate data or ASCII file during printing by use of editing software to insert "1" in first column of data line that starts new page. Written in FORTRAN 77.

  5. A digital processing strategy to optimize hearing aid outputs directly.

    PubMed

    Blamey, Peter J; Martin, Lois F A; Fiket, Hayley J

    2004-01-01

    A new amplification strategy (ADRO), based on 64 independently operating channels, was compared with a nine-channel wide dynamic range compression strategy (WDRC). Open-platform in-the-ear hearing instruments were configured either with ADRO or the manufacturer's WDRC strategy. Twenty-two subjects with mild to moderate hearing loss took home the ADRO or WDRC hearing aids. After three weeks' acclimatization, the aids were evaluated using monosyllables in quiet at 50 to 65 dB SPL and sentences in eight-talker babble. The acclimatization and evaluation were repeated in the second phase of the balanced reverse-block blind experimental design. The ADRO program showed a statistically significant mean advantage of 7.85% word score (95% confidence interval 3.19% to 12.51%; p = 0.002) and 6.41% phoneme score for the monosyllables in quiet (95% confidence interval 2.03% to 10.79%; p = 0.006). A statistically significant advantage of 7.25% was also found for the ADRO program in background noise (95% confidence interval 1.95% to 12.55%; p = 0.010). The results are consistent with earlier data for listeners with moderate to severe hearing loss.

  6. Research on testing field flaws of image intensifier based on spatio-temporal SNR

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Liu, Bingqi; Wu, Dongsheng

    2010-10-01

    Image intensifier is the kernel of low-light-level device. The field flaw is one of the important index parameters of the image intensifier. Traditionally the statistic number of the image intensifier's field flaws is calculated through the people's eyes by the aid of an optical microscope, which main limitation is subjective and inefficient. With the broad application of the high-powered CCD and digital imaging processing method in testing performance of image intensifier, the method of appraising SNR based on spatio-temporal noise theory can accurately reflect the spatio-temporal heterogeneous of fluorescence's output image and fulfill the requirements of digital and automatic test. The limitation of the flaws' shape and position can be disregard and the accurate flaws' inspection can be realized rapidly by this method. In this paper, the main factors of forming the field flaws are analyzed and the mathematic model of spatio-temporal SNR is deduced. The hardware devices of the test system for image intensifier's spatio-temporal SNR are discussed. The spatio-temporal SNR of Gen image intensifier is tested by this test system and the test software based on Visual C++ and Matlab. The digital and automatic test of a factitious field flaw is realized by the theory of spatio-temporal SNR. The test precision can achieve pixel level. The experimental results show that this new method is rational, reliable and visualized.

  7. Toward Functional Augmentative and Alternative Communication for Students with Autism: Manual Signs, Graphic Symbols, and Voice Output Communication Aids.

    ERIC Educational Resources Information Center

    Mirenda, Pat

    2003-01-01

    This article summarizes research regarding the delivery of augmentative and alternative communication (AAC) supports to students with autism. Focus is on: (1) what AAC modality is preferable to use (manual signs or graphic symbols); and (2) what is known about the use of voice output communication aids with people with autism. (Author/DB)

  8. On the implementation of an automated acoustic output optimization algorithm for subharmonic aided pressure estimation

    PubMed Central

    Dave, J. K.; Halldorsdottir, V. G.; Eisenbrey, J. R.; Merton, D. A.; Liu, J. B.; Machado, P.; Zhao, H.; Park, S.; Dianis, S.; Chalek, C. L.; Thomenius, K. E.; Brown, D. B.; Forsberg, F.

    2013-01-01

    Incident acoustic output (IAO) dependent subharmonic signal amplitudes from ultrasound contrast agents can be categorized into occurrence, growth or saturation stages. Subharmonic aided pressure estimation (SHAPE) is a technique that utilizes growth stage subharmonic signal amplitudes for hydrostatic pressure estimation. In this study, we developed an automated IAO optimization algorithm to identify the IAO level eliciting growth stage subharmonic signals and also studied the effect of pulse length on SHAPE. This approach may help eliminate the problems of acquiring and analyzing the data offline at all IAO levels as was done in previous studies and thus, pave the way for real-time clinical pressure monitoring applications. The IAO optimization algorithm was implemented on a Logiq 9 (GE Healthcare, Milwaukee, WI) scanner interfaced with a computer. The optimization algorithm stepped the ultrasound scanner from 0 to 100 % IAO. A logistic equation fitting function was applied with the criterion of minimum least squared error between the fitted subharmonic amplitudes and the measured subharmonic amplitudes as a function of the IAO levels and the optimum IAO level was chosen corresponding to the inflection point calculated from the fitted data. The efficacy of the optimum IAO level was investigated for in vivo SHAPE to monitor portal vein (PV) pressures in 5 canines and was compared with the performance of IAO levels, below and above the optimum IAO level, for 4, 8 and 16 transmit cycles. The canines received a continuous infusion of Sonazoid microbubbles (1.5 μl/kg/min; GE Healthcare, Oslo, Norway). PV pressures were obtained using a surgically introduced pressure catheter (Millar Instruments, Inc., Houston, TX) and were recorded before and after increasing PV pressures. The experiments showed that optimum IAO levels for SHAPE in the canines ranged from 6 to 40 %. The best correlation between changes in PV pressures and in subharmonic amplitudes (r = -0.76; p = 0

  9. Multi-Input/Multi-Output Designated Eigenstructure (MODES): A Computer-Aided Control System Design Program.

    DTIC Science & Technology

    1987-03-01

    must. introduce some tools. The first of these is known as Newton’s Formulas ( Uspensky , 1948: 261). oA 4-32 ’ */ Newton’s Formulas relate the...Academic Press, Inc., 1976. Uspensky , J.V. Theory of Equations. New York: McGraw- Hill Book Company, 1948. Walker, Robert A., et al. "Computer-Aided

  10. Toward Functional Augmentative and Alternative Communication for Students With Autism: Manual Signs, Graphic Symbols, and Voice Output Communication Aids.

    PubMed

    Mirenda, Pat

    2003-07-01

    Many individuals with autism are candidates for augmentative and alternative communication (AAC) systems, either to supplement (i.e., augment) their existing speech or to act as their primary (i.e., alternative) method of expressive communication. The purpose of this article is to summarize research and directions for future research with regard to two questions related to the delivery of AAC supports to these individuals: (a) What AAC modality is preferable to use? and (b) What do we know about the use of voice output communication aids with people with autism?

  11. Compairing Picture Exchange and Voice Output Communication Aids in Young Children with Autism

    ERIC Educational Resources Information Center

    Lorah, Elizabeth R.

    2012-01-01

    The Center for Disease Control estimates that one in 88 births result in a diagnosis of autism (CDC, 2012). Of those individuals diagnosed with autism approximately 25-61% fail to develop vocal output capabilities (Weitxz, Dexter, & Moore, 1997). The use of Augmentative and Alternative Communication (AAC) systems, such as Picture Exchange (PE)…

  12. Developing Snow Model Forcing Data From WRF Model Output to Aid in Water Resource Forecasting

    NASA Astrophysics Data System (ADS)

    Havens, S.; Marks, D. G.; Watson, K. A.; Masarik, M.; Flores, A. N.; Kormos, P.; Hedrick, A. R.

    2015-12-01

    Traditional operational modeling tools used by water managers in the west are challenged by more frequently occurring uncharacteristic stream flow patterns caused by climate change. Water managers are now turning to new models based on the physical processes within a watershed to combat the increasing number of events that do not follow the historical patterns. The USDA-ARS has provided near real time snow water equivalent (SWE) maps using iSnobal since WY2012 for the Boise River Basin in southwest Idaho and since WY2013 for the Tuolumne Basin in California that feeds the Hetch Hetchy reservoir. The goal of these projects is to not only provide current snowpack estimates but to use the Weather Research and Forecasting (WRF) model to drive iSnobal in order to produce a forecasted stream flow when coupled to a hydrology model. The first step is to develop methods on how to create snow model forcing data from WRF outputs. Using a reanalysis 1km WRF dataset from WY2009 over the Boise River Basin, WRF model results like surface air temperature, relative humidity, wind, precipitation, cloud cover, and incoming long wave radiation must be downscaled for use in iSnobal. iSnobal results forced with WRF output are validated at point locations throughout the basin, as well as compared with iSnobal results forced with traditional weather station data. The presentation will explore the differences in forcing data derived from WRF outputs and weather stations and how this affects the snowpack distribution.

  13. Assessment of updated CAD without a new reader study: effect of calibration of computer output on the computer-aided reader performance in CADx

    NASA Astrophysics Data System (ADS)

    Chen, Weijie; Petrick, Nicholas; Sahiner, Berkman

    2011-03-01

    It is very resource-demanding to assess each new version of a CAD system through a new reader study. We conjecture that the aided reader performance on a new version can be predicted by using certain characteristics of the computer output and the reader study conducted when the CAD system was initially introduced. This would likely reduce the need for additional reader studies. However, investigations are needed to develop a sound scientific foundation to test this conjecture. In this work, we consider a CADx system that outputs a disease score to aid the physician in making a diagnostic decision on a located lesion. Our major contribution is to show that calibration, reflected as a change in scale, is a characteristic of the computer output that needs to be considered in order to predict the aided reader performance in a new CADx version without a reader study. We used a bivariate bi-beta distribution to model the joint distribution of the decision variable underlying the reader without aid and the decision variable underlying the version 1 computer output in the initial version. We then applied a monotonic transformation to the computer output to simulate the computer output in a new version, i.e., the scores in the two versions differ only in calibration (specifically a change in scale). By further modeling certain mechanisms that the human reader may use for combining the computer output and the reader-alone scores, we computed the aided reader performance in terms of AUC for the new version of the CADx system. Our results show that the aided reader performance could depend on the degree of calibration difference between the two CAD system outputs. We conclude that for the purpose of predicting the aided reader performance of a new version of the CADx system, ROC performance (or any other rank-based metric) of the stand-alone CADx system may not be sufficient by itself.

  14. How funding structures for HIV/AIDS research shape outputs and utilization: a Swiss case study

    PubMed Central

    2011-01-01

    Background Research policy in the field of HIV has changed substantially in recent decades in Switzerland. Until 2004, social science research on HIV/AIDS was funded by specialized funding agencies. After 2004, funding of such research was “normalized” and integrated into the Swiss National Science Foundation as the main funding agency for scientific research in Switzerland. This paper offers a longitudinal analysis of the relationship between the changing nature of funding structures on the one hand and the production and communication of policy-relevant scientific knowledge in the field of HIV on the other hand. Methods The analysis relies on an inventory of all social sciences research projects on HIV in Switzerland that were funded between 1987 and 2010, including topics covered and disciplines involved, as well as financial data. In addition, in-depth interviews were conducted with 18 stakeholders. Results The analysis highlights that the pre-2004 funding policy ensured good coverage of important social science research themes. Specific incentives and explicit promotion of social science research related to HIV gave rise to a multidisciplinary, integrative and health-oriented approach. The abolition of a specific funding policy in 2004 was paralleled by a drastic reduction in the number of social science research projects submitted for funding, and a decline of public money dedicated to such research. Although the public administration in charge of HIV policy still acknowledges the relevance of findings from social sciences for the development of prevention, treatment and care, HIV-related social science research does not flourish under current funding conditions. Conclusions The Swiss experience sheds light on the difficulties of sustaining social science research and multidisciplinary approaches related to HIV without specialized funding agencies. Future funding policy might not necessarily require specialized agencies, but should better take into

  15. A SECOND MOMENT EXPONENTIAL ERROR BOUND FOR PEAK LIMITED BINARY SYMMETRIC COHERENT CHANNELS AT LOW SNR.

    DTIC Science & Technology

    An exponential-type bound on error rate, Pe, for peak limited binary coherent channels operated at low SNR is presented. The bound depends...exponentially only on the first and second moments of the channel output and serves to justify, in part, the use of SNR calculations for error rate performance

  16. AIDS

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/000594.htm HIV/AIDS To use the sharing features on this page, ... immunodeficiency virus (HIV) is the virus that causes AIDS. When a person becomes infected with HIV, the ...

  17. GD-aided IOL (input-output linearisation) controller for handling affine-form nonlinear system with loose condition on relative degree

    NASA Astrophysics Data System (ADS)

    Zhang, Yunong; Chen, Dechao; Jin, Long; Zhang, Yinyan; Yin, Yonghua

    2016-04-01

    Input-output linearisation (IOL) may encounter a singularity problem when applied to the tracking control of affine-form nonlinear system (AFNS), which may not have a well-defined relative degree. The singularity problem has occurred in the area of control for decades. In this paper, we incorporate the gradient dynamics (GD) into IOL, which leads to the GD-aided IOL method to solve the singularity problem, with the proposition of the loose condition on relative degree. Moreover, detailed theoretical analyses on tracking-error bound and convergence performance of the corresponding GD-aided IOL controller are presented. Simulations and comparisons substantiate that the proposed GD-aided IOL method is capable of completing the tracking-control task and conquering the singularity encountered in the AFNS.

  18. Blind SNR estimation for QAM constellations based on the signal magnitude statistics

    NASA Astrophysics Data System (ADS)

    Dris, Stefanos; Spatharakis, Christos; Bakopoulos, Paraskevas; Lazarou, Ioannis; Avramopoulos, Hercules

    2013-12-01

    We present a novel non-data-aided algorithm that uses only the magnitude of the received signal for accurate estimation of the signal-to-noise ratio (SNR) in M-QAM optical coherent digital receivers. The Koay inversion method that only works with constant-modulus signals, is extended through analytically exact expressions so as to allow application to any multi-level, complex modulation scheme. Performance is evaluated via simulation for formats up to 64-QAM and is shown to be superior than the decision-directed error vector magnitude (EVM) method at low SNR, while outperforming schemes based on the method of moments at high SNR.

  19. Ranking Hearing Aid Input-Output Functions for Understanding Low-, Conversational-, and High-Level Speech in Multitalker Babble

    ERIC Educational Resources Information Center

    Chung, King; Killion, Mead C.; Christensen, Laurel A.

    2007-01-01

    Purpose: To determine the rankings of 6 input-output functions for understanding low-level, conversational, and high-level speech in multitalker babble without manipulating volume control for listeners with normal hearing, flat sensorineural hearing loss, and mildly sloping sensorineural hearing loss. Method: Peak clipping, compression limiting,…

  20. 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.

  1. 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.

  2. X-ray spectrum of Kepler's SNR

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; White, N. E.

    1980-01-01

    Observations made with the solid state spectrometer aboard the Einstein Observatory confirm Kepler's SNR as an X-ray source with an intensity between 1-3 KeV of 7.2 x 10 to the-11th power ergs/sq cm-s. The X-ray spectrum is similar to those of Cas A and Tycho, with strong line emission from the helium-like species of Si, S, and Ar. Direct comparisons to Tycho's SNR suggest a distance of Kepler's SNR of greater than or equal to 5 kpc.

  3. Material-specific transfer function model and SNR in CT

    NASA Astrophysics Data System (ADS)

    Brunner, Claudia C.; Kyprianou, Iacovos S.

    2013-10-01

    This study presents an analytical model for the edge spread function (ESF) of a clinical CT system that allows reliable fits of noisy ESF data. The model was used for the calculation of the material-specific transfer function TF and an estimation of the signal transfer and the signal-to-noise ratio (SNR) in 2D. Images of the Catphan phantom were acquired with a clinical Siemens Somatom Sensation Cardiac 64 CT scanner combining four different x-ray tube outputs (40, 150, 250 and 350 mAs) with four different reconstruction filters, which covered the range from very smooth (B10s) to very sharp (B70s). The images of the high- and mid-contrast cylinders of the phantom’s ‘Geometry and Sensitometry’ module (air, Teflon, Delrin and PMP) were used to sample material-specific ESF curves. The ESF curves were fitted with the analytical model we developed based on a linear combination of Boltzmann and Gaussian functions. The analytical model of the ESF was used to obtain the Fourier-based material-specific transfer function TF, as well as the spatial-domain point spread function (PSF). TF was subsequently used to estimate the signal transfer, which was compared to the actual reconstructed image of a 3.0 mm diameter Teflon pin. The noise power spectrum (NPS) was calculated from images of a uniform water phantom under the same technique parameters. The task-specific SNR was calculated for all technique parameters from the model-based TF, the measured NPS and simulated 3 mm diameter disc signals modeling the aforementioned materials. Bootstrapping was performed to estimate the standard deviation of the TF and the SNR. The analytical model we developed accurately captured the features of the CT ESF data. The coefficient of determination R2, a metric that describes the goodness of the fit, had a median value of 0.9995, and decreased for low tube output, low contrast and the sharp reconstruction filter. Our analysis showed that ESF, PSF and TF depended not only on the

  4. Image Reconstruction in SNR Units: A General Method for SNR Measurement

    PubMed Central

    Kellman, Peter; McVeigh, Elliot R.

    2007-01-01

    The method for phased array image reconstruction of uniform noise images may be used in conjunction with proper image scaling as a means of reconstructing images directly in SNR units. This facilitates accurate and precise SNR measurement on a per pixel basis. This method is applicable to root-sum-of-squares magnitude combining, B1-weighted combining, and parallel imaging such as SENSE. A procedure for image reconstruction and scaling is presented, and the method for SNR measurement is validated with phantom data. Alternative methods that rely on noise only regions are not appropriate for parallel imaging where the noise level is highly variable across the field-of-view. The purpose of this article is to provide a nuts and bolts procedure for calculating scale factors used for reconstructing images directly in SNR units. The procedure includes scaling for noise equivalent bandwidth of digital receivers, FFTs and associated window functions (raw data filters), and array combining. PMID:16261576

  5. Collector-Output Analysis Program

    NASA Technical Reports Server (NTRS)

    Glandorf, D. R.; Phillips, Robert F., II

    1986-01-01

    Collector-Output Analysis Program (COAP) programmer's aid for analyzing output produced by UNIVAC collector (MAP processor). COAP developed to aid in design of segmentation structures for programs with large memory requirements and numerous elements but of value in understanding relationships among components of any program. Crossreference indexes and supplemental information produced. COAP written in FORTRAN 77.

  6. Transfer With SNR High-Speed Transport Protocol.

    DTIC Science & Technology

    1995-12-01

    To validate SNR as a high speed transport protocol, efficient means of transferring large data files are required. The problem is that no file...transfer program is currently implemented for SNR . The SNR protocol was described in IEEE Transactions on Communications 91 Vol. 38 #11. The approach taken...was to modify the Trivial File Transfer Protocol (TFTP) and use it with the SNR Receiver and Transmitter implementations in both the FDDI and Ethernet

  7. SNR-based queue observations at CFHT

    NASA Astrophysics Data System (ADS)

    Devost, Daniel; Moutou, Claire; Manset, Nadine; Mahoney, Billy; Burdullis, Todd; Cuillandre, Jean-Charles; Racine, René

    2016-07-01

    In an effort to optimize the night time utilizing the exquisite weather on Maunakea, CFHT has equipped its dome with vents and is now moving its Queued Scheduled Observing (QSO)1 based operations toward Signal to Noise Ratio (SNR) observing. In this new mode, individual exposure times for a science program are estimated using a model that uses measurements of the weather conditions as input and the science program is considered completed when the depth required by the scientific requirements are reached. These changes allow CFHT to make better use of the excellent seeing conditions provided by Maunakea, allowing us to complete programs in a shorter time than allocated to the science programs.

  8. Altering the SNR by noise manipulation

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.

    2000-12-01

    Irradiation of a photodetector by very short pulses is presented as the primary and perhaps the only remote technology for altering the SNR. Such noise manipulation will decrease the SNR value for certain types of common MIR and LWIR photodetectors. The effect is based on the differences between carrier lifetime, detector material heat transfer rate and altering pulse dwell time. When the pulse width is much less than photodetector rise time, most of the photons cannot generate free carriers, but only heat. Since the heat transfer rate in semiconductors is much slower than carrier's lifetime, high temperature will affect the detector much longer than common input signal correlation length or frame period. We describe thermal, radiometric and electronic circuit models developed to simulate the transfer of short pulses of time-dependent radiant and electrical signals through a photodetector during the alteration. The models are developed to provide an analysis tool for evaluating the time-dependent radiometric sensitivity for the remote gain control of IR photodetectors.

  9. SNR Degradation in Undersampled Phase Measurement Systems

    PubMed Central

    Salido-Monzú, David; Meca-Meca, Francisco J.; Martín-Gorostiza, Ernesto; Lázaro-Galilea, José L.

    2016-01-01

    A wide range of measuring applications rely on phase estimation on sinusoidal signals. These systems, where the estimation is mainly implemented in the digital domain, can generally benefit from the use of undersampling to reduce the digitizer and subsequent digital processing requirements. This may be crucial when the application characteristics necessarily imply a simple and inexpensive sensor. However, practical limitations related to the phase stability of the band-pass filter prior digitization establish restrictions to the reduction of noise bandwidth. Due to this, the undersampling intensity is practically defined by noise aliasing, taking into account the amount of signal-to-noise ratio (SNR) reduction caused by it considering the application accuracy requirements. This work analyzes the relationship between undersampling frequency and SNR reduction, conditioned by the stability requirements of the filter that defines the noise bandwidth before digitization. The effect of undersampling is quantified in a practical situation where phase differences are measured by in-phase and quadrature (I/Q) demodulation for an infrared ranging application. PMID:27783033

  10. 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.

  11. 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.

  12. 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.

  13. CMOS output buffer wave shaper

    NASA Technical Reports Server (NTRS)

    Albertson, L.; Whitaker, S.; Merrell, R.

    1990-01-01

    As the switching speeds and densities of Digital CMOS integrated circuits continue to increase, output switching noise becomes more of a problem. A design technique which aids in the reduction of switching noise is reported. The output driver stage is analyzed through the use of an equivalent RLC circuit. The results of the analysis are used in the design of an output driver stage. A test circuit based on these techniques is being submitted to MOSIS for fabrication.

  14. Fetal cardiac ventricular volume, cardiac output, and ejection fraction determined with four-dimensional ultrasound using Spatio-Temporal Image Correlation (STIC) and Virtual Organ Computed-aided AnaLysis (VOCAL™)

    PubMed Central

    Hamill, Neil; Yeo, Lami; Romero, Roberto; Hassan, Sonia S.; Myers, Stephen A.; Mittal, Pooja; Kusanovic, Juan Pedro; Balasubramaniam, Mamtha; Chaiworapongsa, Tinnakorn; Vaisbuch, Edi; Espinoza, Jimmy; Gotsch, Francesca; Goncalves, Luis F.; Lee, Wesley

    2011-01-01

    Objective To quantify fetal cardiovascular parameters with Spatio-Temporal Image Correlation (STIC) and Virtual Organ Computed-aided AnaLysis (VOCAL™) utilizing the sub-feature: “Contour Finder: Trace”. Study Design A cross-sectional study was designed consisting of patients with normal pregnancies between 19 and 40 weeks of gestation. After STIC datasets were acquired, analysis was performed offline (4DView) and the following cardiovascular parameters were evaluated: ventricular volume in end systole and end diastole, stroke volume, cardiac output, and ejection fraction. To account for fetal size, cardiac output was also expressed as a function of head circumference, abdominal circumference, or femoral diaphysis length. Regression models were fitted for each cardiovascular parameter to assess the effect of gestational age and paired comparisons were made between the left and right ventricles. Results 1) Two hundred and seventeen patients were retrospectively identified, of whom 184 had adequate STIC datasets (85% acceptance); 2) ventricular volume, stroke volume, cardiac output, and adjusted cardiac output increased with gestational age; whereas, the ejection fraction decreased as gestation advanced; 3) the right ventricle was larger than the left in both systole (Right: 0.50 ml, IQR: 0.2 – 0.9; vs. Left: 0.27 ml, IQR: 0.1 – 0.5; p<0.001) and diastole (Right: 1.20 ml, IQR: 0.7 – 2.2; vs. Left: 1.03 ml, IQR: 0.5 – 1.7; p<0.001); 4) there were no differences between the left and right ventricle with respect to stroke volume, cardiac output, or adjusted cardiac output; and 5) the left ventricular ejection fraction was greater than the right (Left: 72.2%, IQR: 64 – 78; vs. Right: 62.4%, IQR: 56 – 69; p<0.001). Conclusion Fetal echocardiography, utilizing STIC and VOCAL™ with the sub-feature: “Contour Finder: Trace”, allows assessment of fetal cardiovascular parameters. Normal fetal cardiovascular physiology is characterized by ventricular

  15. Noise correlations and SNR in phased-array MRS.

    PubMed

    Martini, N; Santarelli, M F; Giovannetti, G; Milanesi, M; De Marchi, D; Positano, V; Landini, L

    2010-01-01

    The acquisition of magnetic resonance spectroscopy (MRS) signals by multiple receiver coils can improve the signal-to-noise ratio (SNR) or alternatively can reduce the scan time maintaining a reliable SNR. However, using phased array coils in MRS studies requires efficient data processing and data combination techniques in order to exploit the sensitivity improvement of the phased array coil acquisition method. This paper describes a novel method for the combination of MRS signals acquired by phased array coils, even in presence of correlated noise between the acquisition channels. In fact, although it has been shown that electric and magnetic coupling mechanisms produce correlated noise in the coils, previous algorithms developed for MRS data combination have ignored this effect. The proposed approach takes advantage of a noise decorrelation stage to maximize the SNR of the combined spectra. In particular Principal Component Analysis (PCA) was exploited to project the acquired spectra in a subspace where the noise vectors are orthogonal. In this subspace the SNR weighting method will provide the optimal overall SNR. Performance evaluation of the proposed method is carried out on simulated (1)H-MRS signals and experimental results are obtained on phantom (1)H-MR spectra using a commercially available 8-element phased array coil. Noise correlations between elements were generally low due to the optimal coil design, leading to a fair SNR gain (about 0.5%) in the center of the field of view (FOV). A greater SNR improvement was found in the peripheral FOV regions.

  16. A new high-latitude low-surface brightness SNR

    NASA Astrophysics Data System (ADS)

    Reich, P.; Kothes, R.; Foster, T.; Reich, W.

    2016-06-01

    We have discovered a new SNR in the Galactic Anticentre at a Galactic latitude of about 10 degrees with the DRAO synthesis telescope at 21-cm. Here we report on follow-up Effelsberg observations at 6-cm. This shell-type SNR is almost circular with a diameter of about 1.5 degrees. Its radio surface brightness is extremely low and it is highly linearly polarized. High-velocity HI-gas from the anti-centre shell seems associated, which places the SNR at a distance between 0.5 kpc and 2.5 kpc.

  17. CGRO/OSSE Observations of the Cassiopeia A SNR (Preprint)

    DTIC Science & Technology

    1996-01-01

    CGRO/OSSE observations of the Cassiopeia A SNR L.-S. The1, M. D. Leising1, J. D. Kurfess2, W. N. Johnson2, D. H. Hartmann1, N. Gehrels3, J. E. Grove2...objects: Cassiopeia A SNR { Nuclear reactions, nucleosyn- thesis, abundances 1. Introduction Gamma-ray observations of Cas A have generated some...CGRO/OSSE observations of the Cassiopeia A SNR 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

  18. Expected Energy Method for Electro-Optical SNR Calculations.

    DTIC Science & Technology

    1984-02-02

    r’AD-Ri39 984 EXPECTED ENERGY METHOD FOR ELECTPO-OPTICRL SNR i/i CALCULRTIONS(U) MASSRCHUSETTS INST OF TECH LEXINGTON LINCOLN LAB G J MAYER 82 FEB 84...ENERGY METHOD FOR ELECTRO-OPTICAL SNR CALCULATIONS * Ci. MA YER Group 9 TECHNICAL REPORT 634 2 FEBRUARY 1984 Approved for public release; distribution...analysis of image and sensor element configuration. This method allows the optimal pixel size to be selected to maximize the expected SNR for any point

  19. New Closed-Form of the Largest Eigenvalue PDF for Max-SNR MIMO System Performances

    NASA Astrophysics Data System (ADS)

    Letessier, Jonathan; Vrigneau, Baptiste; Rostaing, Philippe; Burel, Gilles

    Multiple-input multiple-output (MIMO) maximum-SNR (max-SNR) system employs the maximum ratio combiner (MRC) at the receiver side and the maximum ratio transmitter (MRT) at the transmitter side. Its performances highly depend on MIMO channel characteristics, which vary according to both the number of antennas and their distribution between the transmitter and receiver sides. By using the decomposition of the ordered Wishart distribution in the uncorrelated Rayleigh case, we derived a closed-form expression of the largest eigenvalue probability density function (PDF). The final result yields to an expression form of the PDF where polynomials are multiplied by exponentials; it is worth underlining that, though this form had been previously observed for given couples of antennas, to date no formally-written closed-form was available in the literature for an arbitrary couple. Then, this new expression permits one to quickly and easily get the well known largest eigenvalue PDF and use it to determine the binary error probability (BEP) of the max-SNR.

  20. MMSE precoding for multiuser MISO downlink transmission with non-homogeneous user SNR conditions

    NASA Astrophysics Data System (ADS)

    Nguyen, Duy HN; Le-Ngoc, Tho

    2014-12-01

    This paper is concerned with linear precoding designs for multiuser downlink transmissions. We consider a multiple-input single-output (MISO) system with multiple single-antenna user equipment (UE) experiencing non-homogeneous average signal-to-noise ratio (SNR) conditions. The first part of this work examines different precoding schemes with perfect channel state information (CSI) and average SNR at the base-station (eNB). We then propose a weighted minimum mean squared error (WMMSE) precoder, which takes advantage of the non-homogeneous SNR conditions. Given in a closed-form solution, the proposed WMMSE precoder outperforms other well-known linear precoders, such as zero-forcing (ZF), regularized ZF (RZF), while achieving a close performance to the locally optimal iterative WMMSE (IWMMSE) precoder, in terms of the achievable network sum-rate. In the second part of this work, we consider the non-homogeneous multiuser system with limited and quantized channel quality indicator (CQI) and channel direction indicator (CDI) feedbacks. Based on the CQI and CDI feedback models proposed for the Long-Term Evolution Advanced standard, we then propose a robust WMMSE precoder in a closed-form solution which takes into account the quantization errors. Simulation shows a significant improvement in the achievable network sum-rate by the proposed robust WMMSE precoder, compared to non-robust linear precoder designs.

  1. Basal ganglia outputs map instantaneous position coordinates during behavior.

    PubMed

    Barter, Joseph W; Li, Suellen; Sukharnikova, Tatyana; Rossi, Mark A; Bartholomew, Ryan A; Yin, Henry H

    2015-02-11

    The basal ganglia (BG) are implicated in many movement disorders, yet how they contribute to movement remains unclear. Using wireless in vivo recording, we measured BG output from the substantia nigra pars reticulata (SNr) in mice while monitoring their movements with video tracking. The firing rate of most nigral neurons reflected Cartesian coordinates (either x- or y-coordinates) of the animal's head position during movement. The firing rates of SNr neurons are either positively or negatively correlated with the coordinates. Using an egocentric reference frame, four types of neurons can be classified: each type increases firing during movement in a particular direction (left, right, up, down), and decreases firing during movement in the opposite direction. Given the high correlation between the firing rate and the x and y components of the position vector, the movement trajectory can be reconstructed from neural activity. Our results therefore demonstrate a quantitative and continuous relationship between BG output and behavior. Thus, a steady BG output signal from the SNr (i.e., constant firing rate) is associated with the lack of overt movement, when a stable posture is maintained by structures downstream of the BG. Any change in SNr firing rate is associated with a change in position (i.e., movement). We hypothesize that the SNr output quantitatively determines the direction, velocity, and amplitude of voluntary movements. By changing the reference signals to downstream position control systems, the BG can produce transitions in body configurations and initiate actions.

  2. SNR degradation in square-wave subcarrier downconversion

    NASA Technical Reports Server (NTRS)

    Feria, Y.; Statman, J.

    1992-01-01

    This article presents a study of signal-to-noise ratio (SNR) degradation in the process of square-wave subcarrier downconversion. The study shows three factors that contribute to the SNR degradation: the cutoff of the higher frequency components in the data, the approximation of a square wave with a finite number of harmonics, and nonideal filtering. Both analytical and simulation results are presented.

  3. 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.

  4. SNR approach for performance evaluation of time-stretching photonic analogue to digital converter system.

    PubMed

    Alves, Tiago M F; Cartaxo, Adolfo V T

    2011-01-17

    A semi-analytical simulation method (SASM) is proposed to evaluate the signal-to-noise ratio (SNR) of time stretched signals at the output of photonic analogue-to-digital converter (Ph-ADC) system. Analytical expressions of the signal at Ph-ADC output considering generic electrical signals applied to the electro-optic modulators of the Ph-ADC are derived. The contribution to the total variance of the received signal from the noise introduced by the electrical transmitter and receiver, and by the optical amplifier are derived analytically taking into account the pulsed nature of the optical signal. The proposed SASM shows excellent agreement of SNR estimates with the estimates provided by Monte Carlo simulation. This result is confirmed for variance dominantly imposed by the noise introduced by the electrical transmitter, by the optical amplifier and by the electrical receiver. A simplified approach is also proposed and compared with previous work. It is shown that mean power estimates obtained from this simplified approach are valid while the modulator is operating in the linear region and the signal is not affected by the frequency response of the electrical receiver filter. Additionally, it is concluded that the estimates of the noise variance due to the electrical transmitter are acceptable when a small signal analysis of noise along the Ph-ADC is valid.

  5. BK Channels Reveal Novel Phosphate Sensitivity in SNr Neurons

    PubMed Central

    Ji, Juan Juan; Chen, Lianwan; Duan, Xuezhi; Song, Xueqin; Su, Wenting; Zhang, Peng; Li, Li; Bai, Shuyun; Sun, Yingchun; Inagaki, Nobuya

    2012-01-01

    Whether large conductance Ca2+-activated potassium (BK) channels are present in the substantia nigra pars reticulata (SNr) is a matter of debate. Using the patch-clamp technique, we examined the functional expression of BK channels in neurons of the SNr and showed that the channels were activated or inhibited by internal high-energy phosphates (IHEPs) at positive and negative membrane potentials, respectively. SNr neurons showed membrane potential hyperpolarization under glucose-deprivation conditions which was attenuated by paxilline, a specific BK channel blocker. In addition, Fluo-3 fluorescence recording detected an increase in the level of internal free calcium ([Ca2+]i) during ischemic hyperpolarization. These results confirm that BK channels are present in SNr neurons and indicate that their unique IHEP sensitivity is requisite in neuronal ischemic responses. Bearing in mind that the KATP channel blocker tolbutamide also attenuated the hyperpolarization, we suggest that BK channels may play a protective role in the basal ganglia by modulating the excitability of SNr neurons along with KATP channels under ischemic stresses. PMID:23284908

  6. 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.

  7. A priori SNR estimation and noise estimation for speech enhancement.

    PubMed

    Yao, Rui; Zeng, ZeQing; Zhu, Ping

    2016-01-01

    A priori signal-to-noise ratio (SNR) estimation and noise estimation are important for speech enhancement. In this paper, a novel modified decision-directed (DD) a priori SNR estimation approach based on single-frequency entropy, named DDBSE, is proposed. DDBSE replaces the fixed weighting factor in the DD approach with an adaptive one calculated according to change of single-frequency entropy. Simultaneously, a new noise power estimation approach based on unbiased minimum mean square error (MMSE) and voice activity detection (VAD), named UMVAD, is proposed. UMVAD adopts different strategies to estimate noise in order to reduce over-estimation and under-estimation of noise. UMVAD improves the classical statistical model-based VAD by utilizing an adaptive threshold to replace the original fixed one and modifies the unbiased MMSE-based noise estimation approach using an adaptive a priori speech presence probability calculated by entropy instead of the original fixed one. Experimental results show that DDBSE can provide greater noise suppression than DD and UMVAD can improve the accuracy of noise estimation. Compared to existing approaches, speech enhancement based on UMVAD and DDBSE can obtain a better segment SNR score and composite measure covl score, especially in adverse environments such as non-stationary noise and low-SNR.

  8. A priori SNR estimation and noise estimation for speech enhancement

    NASA Astrophysics Data System (ADS)

    Yao, Rui; Zeng, ZeQing; Zhu, Ping

    2016-12-01

    A priori signal-to-noise ratio (SNR) estimation and noise estimation are important for speech enhancement. In this paper, a novel modified decision-directed (DD) a priori SNR estimation approach based on single-frequency entropy, named DDBSE, is proposed. DDBSE replaces the fixed weighting factor in the DD approach with an adaptive one calculated according to change of single-frequency entropy. Simultaneously, a new noise power estimation approach based on unbiased minimum mean square error (MMSE) and voice activity detection (VAD), named UMVAD, is proposed. UMVAD adopts different strategies to estimate noise in order to reduce over-estimation and under-estimation of noise. UMVAD improves the classical statistical model-based VAD by utilizing an adaptive threshold to replace the original fixed one and modifies the unbiased MMSE-based noise estimation approach using an adaptive a priori speech presence probability calculated by entropy instead of the original fixed one. Experimental results show that DDBSE can provide greater noise suppression than DD and UMVAD can improve the accuracy of noise estimation. Compared to existing approaches, speech enhancement based on UMVAD and DDBSE can obtain a better segment SNR score and composite measure c ovl score, especially in adverse environments such as non-stationary noise and low-SNR.

  9. 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.

  10. Threshold-Based Bit Error Rate for Stopping Iterative Turbo Decoding in a Varying SNR Environment

    NASA Astrophysics Data System (ADS)

    Mohamad, Roslina; Harun, Harlisya; Mokhtar, Makhfudzah; Adnan, Wan Azizun Wan; Dimyati, Kaharudin

    2017-01-01

    Online bit error rate (BER) estimation (OBE) has been used as a stopping iterative turbo decoding criterion. However, the stopping criteria only work at high signal-to-noise ratios (SNRs), and fail to have early termination at low SNRs, which contributes to an additional iteration number and an increase in computational complexity. The failure of the stopping criteria is caused by the unsuitable BER threshold, which is obtained by estimating the expected BER performance at high SNRs, and this threshold does not indicate the correct termination according to convergence and non-convergence outputs (CNCO). Hence, in this paper, the threshold computation based on the BER of CNCO is proposed for an OBE stopping criterion (OBEsc). From the results, OBEsc is capable of terminating early in a varying SNR environment. The optimum number of iterations achieved by the OBEsc allows huge savings in decoding iteration number and decreasing the delay of turbo iterative decoding.

  11. 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.

  12. 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.

  13. 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.

  14. A Kinship between Sgr A East and the EGRET SNR's

    NASA Astrophysics Data System (ADS)

    Fatuzzo, M.; Melia, F.

    2003-05-01

    Sgr A East appears to be a single, mixed-morphology 10,000-year-old supernova remnant (SNR) at the Galactic center. It also appears to belong to a class of remnants that have been observed and detected at 1720 MHz, the transition frequency of OH maser emission. However, if the EGRET source 3EG J1746-2852 coincident with the Galactic center is itself associated with this object, it would endow it with a γ -ray luminosity almost two orders of magnitude greater than that of the other EGRET-detected SNR's. We here reconsider the viability of a pion-production mechanism as the source of the broadband emission observed from Sgr A East, and show that what connects these objects---and ultimately also accounts for their different γ -ray emissivity---is the very important interaction between the expanding SNR shell and the surrounding molecular cloud environment. The singularly high γ -ray luminosity of Sgr A East, as well as its unusually steep radio spectral index, can thereby be attributed to the high-density (nH=103 cm-3), strong magnetized (B ˜ 0.18 mG) environment in which it is located.

  15. An Implementation of the SNR High Speed Network Communication Protocol (Receiver Part).

    DTIC Science & Technology

    1995-03-01

    This thesis work is to implement the receiver pan of the SNR high speed network transport protocol. The approach was to use the Systems of...the SCM specification itself. The result was a correctly functioning program which implemented the SNR protocol. The system was tested using different...part of the SNR high speed transport protocol; (2) testing and integration with the transmitter part of the SNR transport protocol on an FDDI data

  16. Robust presynaptic serotonin 5-HT1B receptor inhibition of the striatonigral output and its sensitization by chronic fluoxetine treatment

    PubMed Central

    Ding, Shengyuan; Li, Li

    2015-01-01

    The striatonigral projection is a striatal output pathway critical to motor control, cognition, and emotion regulation. Its axon terminals in the substantia nigra pars reticulata (SNr) express a high level of serotonin (5-HT) type 1B receptors (5-HT1BRs), whereas the SNr also receives an intense 5-HT innervation that expresses 5-HT transporters, providing an anatomic substrate for 5-HT and selective 5-HT reuptake inhibitor (SSRI)-based antidepressant treatment to regulate the striatonigral output. In this article we show that 5-HT, by activating presynaptic 5-HT1BRs on the striatonigral axon terminals, potently inhibited the striatonigral GABA output, as reflected in the reduction of the striatonigral inhibitory postsynaptic currents in SNr GABA neurons. Functionally, 5-HT1BR agonism reduced the striatonigral GABA output-induced pause of the spontaneous high-frequency firing in SNr GABA neurons. Equally important, chronic SSRI treatment with fluoxetine enhanced this presynaptic 5-HT1BR-mediated pause reduction in SNr GABA neurons. Taken together, these results indicate that activation of the 5-HT1BRs on the striatonigral axon terminals can limit the motor-promoting GABA output. Furthermore, in contrast to the desensitization of 5-HT1 autoreceptors, chronic SSRI-based antidepressant treatment sensitizes this presynaptic 5-HT1BR-mediated effect in the SNr, a novel cellular mechanism that alters the striatonigral information transfer, potentially contributing to the behavioral effects of chronic SSRI treatment. PMID:25787955

  17. 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

  18. Impact of SNR and Gain-Function Over- and Under-estimation on Speech Intelligibility.

    PubMed

    Chen, Fei; Loizou, Philipos C

    2012-02-01

    Most noise reduction algorithms rely on obtaining reliable estimates of the SNR of each frequency bin. For that reason, much work has been done in analyzing the behavior and performance of SNR estimation algorithms in the context of improving speech quality and reducing speech distortions (e.g., musical noise). Comparatively little work has been reported, however, regarding the analysis and investigation of the effect of errors in SNR estimation on speech intelligibility. It is not known, for instance, whether it is the errors in SNR overestimation, errors in SNR underestimation, or both that are harmful to speech intelligibility. Errors in SNR estimation produce concomitant errors in the computation of the gain (suppression) function, and the impact of gain estimation errors on speech intelligibility is unclear. The present study assesses the effect of SNR estimation errors on gain function estimation via sensitivity analysis. Intelligibility listening studies were conducted to validate the sensitivity analysis. Results indicated that speech intelligibility is severely compromised when SNR and gain over-estimation errors are introduced in spectral components with negative SNR. A theoretical upper bound on the gain function is derived that can be used to constrain the values of the gain function so as to ensure that SNR overestimation errors are minimized. Speech enhancement algorithms that can limit the values of the gain function to fall within this upper bound can improve speech intelligibility.

  19. Ergogenic aids.

    PubMed

    Coyle, E F

    1984-07-01

    The catabolism of bodily fuels provides the energy for muscular work. Work output can be limited by the size of fuel reserves, the rate of their catabolism, the build-up of by-products, or the neurologic activation of muscle. A substance that favorably affects a step that is normally limiting, and thus increases work output, can be considered an ergogenic aid. The maximal amount of muscular force generated during brief contractions can be acutely increased during hypnosis and with the ingestion of a placebo or psychomotor stimulant. This effect is most obvious in subjects under laboratory conditions and is less evident in athletes who are highly motivated prior to competition. Fatigue is associated with acidosis in the working musculature when attempts are made to maximize work output during a 4 to 15-minute period. Sodium bicarbonate ingestion may act to buffer the acid produced, provided that blood flow to the muscle is adequate. Prolonged intense exercise can be maintained for approximately two hours before carbohydrate stores become depleted. Carbohydrate feedings delay fatigue during prolonged exercise, especially in subjects who display a decline in blood glucose during exercise in the fasting state. Caffeine ingestion prior to an endurance bout has been reported to allow an individual to exercise somewhat more intensely than he or she would otherwise. Its effect may be mediated by augmenting fat metabolism or by altering the perception of effort. Amphetamines may act in a similar manner. Water ingestion during prolonged exercise that results in dehydration and hyperthermia can offset fluid losses and allow an individual to better maintain work output while substantially reducing the risk of heat-related injuries.

  20. 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.

  1. 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.

  2. Three-Dimensional Rapidly Scanning Laser Doppler Velocimeter with Low SNR Signal Processing

    DTIC Science & Technology

    1990-11-30

    Three-Dimensional Rapidly Scanning Laser Doppler Velocimeter with Low SNR Signal Processing 12. PERSONAL AUTHOR(S) Kevin A. Shinpaugh and Rog er L...curvature for concave mirror or lens surface s .................... object distance from lens s.. ................. image distance from lens SNR ...where the signal-to-noise ratio ( SNR ) of the PMT signal is 20 dB and signal processing is performed via the fast Fourier trasnform (FFT) with zero

  3. Tensor Invariant Processing for Munitions/Clutter Classifications Interim Report on SNR and Background Leveling Requirements

    DTIC Science & Technology

    2012-12-01

    INTERIM REPORT Tensor Invariant Processing for Munitions/Clutter Classifications Interim Report on SNR and Background Leveling Requirements...00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Tensor Invariant Processing for Munitions/Clutter Classifications Interim Report on SNR and...Camp Beale in 2011 and found no impact due to signal-to-noise ratio ( SNR ) and background leveling effects. However, the minimum polarizability

  4. Enhancement of Signal to Noise Ratio Using Bispectrum. A Quantitative Analysis for Very Low SNR

    DTIC Science & Technology

    2001-10-25

    Enhancement of Signal to Noise Ratio Using Bispectrum A Quantitative Analysis for Very Low SNR Payam Yeganeh, Mohammad H. Moradi, Ali Reshad...Dept. of Biomedical Engineering, AMIR KABIR University of Technology Abstract- Bispectrum has been widely used to enhance the SNR . This is based...consider the use of Bispectrum techniques when repeated measurements are made of a deterministic signal embedded in random noise where SNR is in the

  5. Control of Basal Ganglia Output by Direct and Indirect Pathway Projection Neurons

    PubMed Central

    Freeze, Benjamin S.; Kravitz, Alexxai V.; Hammack, Nora; Berke, Joshua D.

    2013-01-01

    The direct and indirect efferent pathways from striatum ultimately reconverge to influence basal ganglia output nuclei, which in turn regulate behavior via thalamocortical and brainstem motor circuits. However, the distinct contributions of these two efferent pathways in shaping basal ganglia output are not well understood. We investigated these processes using selective optogenetic control of the direct and indirect pathways, in combination with single-unit recording in the basal ganglia output nucleus substantia nigra pars reticulata (SNr) in mice. Optogenetic activation of striatal direct and indirect pathway projection neurons produced diverse cellular responses in SNr neurons, with stimulation of each pathway eliciting both excitations and inhibitions. Despite this response heterogeneity, the effectiveness of direct pathway stimulation in producing movement initiation correlated selectively with the subpopulation of inhibited SNr neurons. In contrast, effective indirect pathway-mediated motor suppression was most strongly influenced by excited SNr neurons. Our results support the theory that key basal ganglia output neurons serve as an inhibitory gate over motor output that can be opened or closed by striatal direct and indirect pathways, respectively. PMID:24259575

  6. Improved SNR of phased-array PERES coils via simulation study.

    PubMed

    Rodríguez, Alfredo O; Medina, Lucía

    2005-09-21

    A computational comparison of signal-to-noise ratio (SNR) was performed between a conventional phased array of two circular-shaped coils and a petal resonator surface array. The quasi-static model and phased-array optimum SNR were combined to derive an SNR formula for each array. Analysis of mutual inductance between coil petals was carried out to compute the optimal coil separation and optimum number of petal coils. Mutual interaction between coil arrays was not included in the model because this does not drastically affect coil performance. Phased arrays of PERES coils show a 114% improvement in SNR over that of the simplest circular configuration.

  7. Hearing Aids

    MedlinePlus

    ... Health Info » Hearing, Ear Infections, and Deafness Hearing Aids On this page: What is a hearing aid? ... the ear through a speaker. How can hearing aids help? Hearing aids are primarily useful in improving ...

  8. Garrett County Aids AID

    ERIC Educational Resources Information Center

    Appalachia, 1975

    1975-01-01

    Garrett County, Maryland volunteered to act as a pre-overseas learning laboratory for AID (Agency for International Development) interns who practiced data collection and planning techniques with the help of local citizenry. (JC)

  9. VLA observations of three extragalactic SNR at 20 and 6 cm

    NASA Technical Reports Server (NTRS)

    Dickel, J. R.; Silverman, A.; Dodorico, S.

    1985-01-01

    A radio search has been conducted for optical SNR candidates in the external galaxies NGC 185, IC 1613, and NGC 6822. A faint, nonthermal radio source has been found at the expected position in IC 1613. Upper limits are placed on the objects in NGC 185 and NGC 6822. All three appear fainter than typical SNR of the same size in the Milky Way.

  10. Smoothed Particle Inference Analysis of SNR RCW 103

    NASA Astrophysics Data System (ADS)

    Frank, Kari A.; Burrows, David N.; Dwarkadas, Vikram

    2016-04-01

    We present preliminary results of applying a novel analysis method, Smoothed Particle Inference (SPI), to an XMM-Newton observation of SNR RCW 103. SPI is a Bayesian modeling process that fits a population of gas blobs ("smoothed particles") such that their superposed emission reproduces the observed spatial and spectral distribution of photons. Emission-weighted distributions of plasma properties, such as abundances and temperatures, are then extracted from the properties of the individual blobs. This technique has important advantages over analysis techniques which implicitly assume that remnants are two-dimensional objects in which each line of sight encompasses a single plasma. By contrast, SPI allows superposition of as many blobs of plasma as are needed to match the spectrum observed in each direction, without the need to bin the data spatially. This RCW 103 analysis is part of a pilot study for the larger SPIES (Smoothed Particle Inference Exploration of SNRs) project, in which SPI will be applied to a sample of 12 bright SNRs.

  11. Chandra Observation of Galactic SNR G299.2-2.9

    NASA Astrophysics Data System (ADS)

    Park, Sangwook; Slane, P. O.; Hughes, J. P.; Mori, K.; Burrows, D. N.; Garmire, G. P.

    2006-09-01

    We report on the results from our Chandra observation of a Galactic supernova remnant (SNR) G299.2-2.9. The high resolution Chandra images clearly reveal the shell-type morphology of the SNR. The circumferential regions of the SNR consist of complex emission features of bright shells, small knots, and faint diffuse emission extending beyond the shell. These features indicate that the SNR blast wave is propagating into highly inhomogeneous ambient medium. On the other hand, the central region of the SNR is a faint diffuse nebula that reveals strong enhancements in Si, S, and Fe ejecta. The presence of the overabundant Si-group elements, with no such enhancements in the O-group elemental abundances, may suggest a Type Ia origin for G299.2-2.9.

  12. Music and hearing aids.

    PubMed

    Madsen, Sara M K; Moore, Brian C J

    2014-10-31

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems.

  13. Music and Hearing Aids

    PubMed Central

    Moore, Brian C. J.

    2014-01-01

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems. PMID:25361601

  14. Functional circuit mapping of striatal output nuclei using simultaneous deep brain stimulation and fMRI.

    PubMed

    Van Den Berge, Nathalie; Albaugh, Daniel L; Salzwedel, Andrew; Vanhove, Christian; Van Holen, Roel; Gao, Wei; Stuber, Garret D; Ian Shih, Yen-Yu

    2017-02-01

    The substantia nigra pars reticulata (SNr) and external globus pallidus (GPe) constitute the two major output targets of the rodent striatum. Both the SNr and GPe converge upon thalamic relay nuclei (directly or indirectly, respectively), and are traditionally modeled as functionally antagonistic relay inputs. However, recent anatomical and functional studies have identified unanticipated circuit connectivity in both the SNr and GPe, demonstrating their potential as far more than relay nuclei. In the present study, we employed simultaneous deep brain stimulation and functional magnetic resonance imaging (DBS-fMRI) with cerebral blood volume (CBV) measurements to functionally and unbiasedly map the circuit- and network level connectivity of the SNr and GPe. Sprague-Dawley rats were implanted with a custom-made MR-compatible stimulating electrode in the right SNr (n=6) or GPe (n=7). SNr- and GPe-DBS, conducted across a wide range of stimulation frequencies, revealed a number of surprising evoked responses, including unexpected CBV decreases within the striatum during DBS at either target, as well as GPe-DBS-evoked positive modulation of frontal cortex. Functional connectivity MRI revealed global modulation of neural networks during DBS at either target, sensitive to stimulation frequency and readily reversed following cessation of stimulation. This work thus contributes to a growing literature demonstrating extensive and unanticipated functional connectivity among basal ganglia nuclei.

  15. A push-pull CORF model of a simple cell with antiphase inhibition improves SNR and contour detection.

    PubMed

    Azzopardi, George; Rodríguez-Sánchez, Antonio; Piater, Justus; Petkov, Nicolai

    2014-01-01

    We propose a computational model of a simple cell with push-pull inhibition, a property that is observed in many real simple cells. It is based on an existing model called Combination of Receptive Fields or CORF for brevity. A CORF model uses as afferent inputs the responses of model LGN cells with appropriately aligned center-surround receptive fields, and combines their output with a weighted geometric mean. The output of the proposed model simple cell with push-pull inhibition, which we call push-pull CORF, is computed as the response of a CORF model cell that is selective for a stimulus with preferred orientation and preferred contrast minus a fraction of the response of a CORF model cell that responds to the same stimulus but of opposite contrast. We demonstrate that the proposed push-pull CORF model improves signal-to-noise ratio (SNR) and achieves further properties that are observed in real simple cells, namely separability of spatial frequency and orientation as well as contrast-dependent changes in spatial frequency tuning. We also demonstrate the effectiveness of the proposed push-pull CORF model in contour detection, which is believed to be the primary biological role of simple cells. We use the RuG (40 images) and Berkeley (500 images) benchmark data sets of images with natural scenes and show that the proposed model outperforms, with very high statistical significance, the basic CORF model without inhibition, Gabor-based models with isotropic surround inhibition, and the Canny edge detector. The push-pull CORF model that we propose is a contribution to a better understanding of how visual information is processed in the brain as it provides the ability to reproduce a wider range of properties exhibited by real simple cells. As a result of push-pull inhibition a CORF model exhibits an improved SNR, which is the reason for a more effective contour detection.

  16. HIV / AIDS

    MedlinePlus

    ... facebook share with twitter share with linkedin HIV/AIDS HIV, or human immunodeficiency virus, is the virus ... HIV/AIDS. Why Is the Study of HIV/AIDS a Priority for NIAID? Nearly 37 million people ...

  17. Hearing Aids

    MedlinePlus

    ... and Consumer Devices Consumer Products Hearing Aids Hearing Aids Share Tweet Linkedin Pin it More sharing options ... to restrict your daily activities. Properly fitted hearing aids and aural rehabilitation (techniques used to identify and ...

  18. Hearing Aids

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Hearing Aids KidsHealth > For Teens > Hearing Aids Print A A ... with certain types of hearing loss. How Hearing Aids Help So you went to audiologist and found ...

  19. 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.

  20. An Octahedral Shear Strain Based measure of SNR for 3D MR Elastography

    PubMed Central

    McGarry, MDJ; Van Houten, EEW; Perriñez, PR; Pattison, AJ; Weaver, JB; Paulsen, KD

    2011-01-01

    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 MR elastography, 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 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. PMID:21654044

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

    PubMed

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

    2011-07-07

    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.

  2. Directional Microphone Hearing Aids in School Environments: Working toward Optimization

    ERIC Educational Resources Information Center

    Ricketts, Todd A.; Picou, Erin M.; Galster, Jason

    2017-01-01

    Purpose: The hearing aid microphone setting (omnidirectional or directional) can be selected manually or automatically. This study examined the percentage of time the microphone setting selected using each method was judged to provide the best signalto-noise ratio (SNR) for the talkers of interest in school environments. Method: A total of 26…

  3. HRI Observations of Balmer Dominated Filaments in the SNR RCW86

    NASA Technical Reports Server (NTRS)

    Long, Knox S.

    1999-01-01

    The objective of this project was to use the ROSAT HRI to study the recently discovered optical Balmer-dominated filaments in the young SNR R-CW86. The observations provide complete high-resolution X-ray coverage of the shell of the SNR. These X-ray observations are combined with new optical observations (both imaging and spectroscopic), and new high resolution radio observations to provide a better overall understanding of the state of the remnant (Sedov or reverse shock), its history (as the possible SNR of SN 185 AD), and the physics of non-radiative shocks.

  4. Shock chemistry in the molecular clouds associated with SNR IC 443

    NASA Technical Reports Server (NTRS)

    Ziurys, L. M.; Snell, Ronald L.; Dickman, R. L.

    1989-01-01

    Observations of several interstellar molecules toward the highly perturbed B and G clouds associated with SNR IC 443 are reported. The results suggest that hot and dense material is present in the SNR, and that shocks are present in both regions. The HCO(+) abundance is shown to be a few times greater that found in cold quiescent gas, in contradiction with previous results. The SO, CS, CN, and NH3 abundances are similar to those found in cold dark clouds.

  5. SNR Limits to Achieving the Cramer-Rao Lower Bounds with PCID

    DTIC Science & Technology

    2010-01-01

    TP-2010-1008 SNR LIMITS TO ACHIEVING THE CRAMER-RAO LOWER BOUNDS WITH PCID Chuck...To) Jan 7, 2007- Jan 1, 2010 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In House DF701944 SNR Limits to Achieving the Cramer-Rao Lower Bounds...Purpose for the Research • To further understand the achievability of CRBs by MFBD algorithms (PCID is being used for these results) - At what SNRs

  6. 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

  7. 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

  8. Radio perspectives on the Monoceros SNR G205.5+0.5

    NASA Astrophysics Data System (ADS)

    Xiao, L.; Zhu, M.

    2012-09-01

    Context. The Monoceros supernova remnant (SNR G205.5+0.5) is a large shell-type SNR located in the Rosette molecular complex and thought to be interacting with the Rosette Nebula. Aims: We aim to re-examine the radio spectral index and its spatial variation over the Monoceros SNR as well as study its properties of evolution within the complex interstellar medium. Methods: We extracted radio continuum data for the Monoceros complex region from the Effelsberg 21 cm and 11 cm surveys and the Urumqi 6 cm polarization survey. We used the new Arecibo GALFA-HI survey data with much higher resolution and sensitivity than that previously available to identify the HI shell related with the SNR. Multi-wavelengths data are included to investigate the properties of the SNR. Results: The spectral index α (Sν ∝ να) averaged over the SNR is -0.41 ± 0.16. The TT-plots and the distribution of α over the SNR show spatial variations that steepen toward the inner western filamentary shell. Polarized emission is prominent on the western filamentary shell region. The RM there is estimated to be about 30 ± 77n rad m-2, where the n = 1 solution is preferred, and the magnetic field has a strength of about 9.5 μG. From the HI channel maps, further evidence is provided for an interaction between the Monoceros SNR and the Rosette Nebula. We identify partial neutral hydrogen shell structures in the northwestern region at velocities of +15 km s-1 circumscribing the continuum emission. The HI shell has swept up a mass of about 4000 M⊙ for a distance of 1.6 kpc. The western HI shell, well associated with the dust emission, is found to lie outside of the radio shell. We suggest that the Monoceros SNR is evolving within a cavity blown out by the progenitor and has triggered part of the star formation in the Rosette Nebula. Conclusions: The Monoceros SNR is interacting with the ambient interstellar medium with ultra-high energy emission detected. Its interaction with the Rosette Nebula is

  9. Hearing Aids

    MedlinePlus

    ... more in both quiet and noisy situations. Hearing aids help people who have hearing loss from damage ... your doctor. There are different kinds of hearing aids. They differ by size, their placement on or ...

  10. AIDS (image)

    MedlinePlus

    AIDS (acquired immune deficiency syndrome) is caused by HIV (human immunodeficiency virus), and is a syndrome that ... life-threatening illnesses. There is no cure for AIDS, but treatment with antiviral medicine can suppress symptoms. ...

  11. 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

  12. 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.

  13. An imaging and spectroscopic study of the peculiar SNR 3C397 with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Safi-Harb, Samar; Franzmann, Erica

    The SNR 3C 397 has a peculiar box-like morphology with a central X-ray `hot spot' and a sharp boundary in the west. Earlier X-ray spectroscopy with ASCA and Chandra showed that the central spot is thermal in nature, that the column density increases from east to west, and that the X-ray spectrum is dominated by thermal emission from (at least) two compo-nents: a low-temperature plasma characterized by a high ionization timescale, mixed with a high-temperature, ejecta-dominated plasma (mainly Fe-K), characterized by a low ionization timescale. This, together with millimeter observations of the environs of 3C 397, led to the suggestion that 3C 397 is a ˜5 kyr old SNR expanding in an inhomogeneous medium, en-countering a molecular cloud towards the west, and evolving into a mixed-morphology SNR. Most recently, new CO observations showed that the SNR is well confined in a cavity of molec-ular gas and embedded at the edge of a molecular cloud at VLSR ˜32 km/s. The 12 CO line broadening of the 32 km/s component provided direct evidence of interaction between the SNR and a molecular cloud at the western boundary of the remnant. To date, there is no evidence of a compact object or a pulsar wind nebula associated with this remnant. We here present an XMM-Newton imaging and spectroscopic analysis of 3C 397 targeted to 1) map the ejecta distribution (in particular of Mg, Si, S and Fe) across the SNR, 2) constrain the spectral and physical properties of the supernova and its progenitor star, and 3) address the absence of a neutron star or wind nebula associated with the SNR.

  14. Governmentally amplified output volatility

    NASA Astrophysics Data System (ADS)

    Funashima, Yoshito

    2016-11-01

    Predominant government behavior is decomposed by frequency into several periodic components: updating cycles of infrastructure, Kuznets cycles, fiscal policy over business cycles, and election cycles. Little is known, however, about the theoretical impact of such cyclical behavior in public finance on output fluctuations. Based on a standard neoclassical growth model, this study intends to examine the frequency at which public investment cycles are relevant to output fluctuations. We find an inverted U-shaped relationship between output volatility and length of cycle in public investment. This implies that periodic behavior in public investment at a certain frequency range can cause aggravated output resonance. Moreover, we present an empirical analysis to test the theoretical implication, using the U.S. data in the period from 1968 to 2015. The empirical results suggest that such resonance phenomena change from low to high frequency.

  15. [The analysis for improving the SNR of blood components noninvasive measurement with DS method].

    PubMed

    Li, Gang; Wang, Hui-quan; Zhao, Zhe; Lin, Ling; Zhang, Bao-ju; Wu, Xiao-rong

    2012-08-01

    In order to increase the accuracy of blood components measurement and enhance the stability of prediction model, the quantitative signal-noise-ratio (SNR) analysis of measuring instruments based on dynamic spectrum (DS) and preprocessing method was conducted. The SNR of DS is increased after adding boxcar integrator, decreasing wavelength revolution, balancing the DS's SNR and excluding gross errors in preprocessing according to experiment results. Two volunteers were tested continuously for many times using the DS data acquiring system. The correlation coefficients of the each volunteer's DS data was increased from 0.934 and 0.953 to 0.991 and 0.987, respectively. Moreover, the gap between the correlation coefficient of the same volunteer's DS and different volunteers' DS is increased too, which shows that the SNR can be improved by these methods. The quantitative SNR analysis can guide the way of choosing preprocessing method efficiently, which will create the condition for clinical application of the blood components noninvasive measurement.

  16. 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.

  17. The SWI/SNF Complex Protein Snr1 Is a Tumor Suppressor in Drosophila Imaginal Tissues.

    PubMed

    Xie, Gengqiang; Chen, Hanqing; Jia, Dongyu; Shu, Zhiqiang; Palmer, William Hunt; Huang, Yi-Chun; Zeng, Xiankun; Hou, Steven X; Jiao, Renjie; Deng, Wu-Min

    2017-02-15

    Components of the SWI/SNF chromatin-remodeling complex are among the most frequently mutated genes in various human cancers, yet only SMARCB1/hSNF5, a core member of the SWI/SNF complex, is mutated in malignant rhabdoid tumors (MRT). How SMARCB1/hSNF5 functions differently from other members of the SWI/SNF complex remains unclear. Here, we use Drosophila imaginal epithelial tissues to demonstrate that Snr1, the conserved homolog of human SMARCB1/hSNF5, prevents tumorigenesis by maintaining normal endosomal trafficking-mediated signaling cascades. Removal of Snr1 resulted in neoplastic tumorigenic overgrowth in imaginal epithelial tissues, whereas depletion of any other members of the SWI/SNF complex did not induce similar phenotypes. Unlike other components of the SWI/SNF complex that were detected only in the nucleus, Snr1 was observed in both the nucleus and the cytoplasm. Aberrant regulation of multiple signaling pathways, including Notch, JNK, and JAK/STAT, was responsible for tumor progression upon snr1-depletion. Our results suggest that the cytoplasmic Snr1 may play a tumor suppressive role in Drosophila imaginal tissues, offering a foundation for understanding the pivotal role of SMARCB1/hSNF5 in suppressing MRT during early childhood. Cancer Res; 77(4); 862-73. ©2017 AACR.

  18. Optimizing SNR for indoor visible light communication via selecting communicating LEDs

    NASA Astrophysics Data System (ADS)

    Wang, Lang; Wang, Chunyue; Chi, Xuefen; Zhao, Linlin; Dong, Xiaoli

    2017-03-01

    In this paper, we investigate the layout of LED to optimize SNR by selecting communicating LEDs (C-LEDs) in indoor visible light communication (VLC) system. Due to the inter-symbol interference (ISI) caused by the different arrival time of different optical rays, the SNR for any user is not optimal if a simple layout is adopted. It is interesting to investigate the LEDs layout for achieving optimal SNR in indoor VLC system. For a single user, LED signal is divided into the positive and negative components, they provide the power of desired signal and the power of ISI respectively. We introduce the concept of valid ratio (VR) which refers to the value of positive component over the negative component. Then we propose a VR threshold-based LED selection scheme which chooses C-LEDs by their VRs. For downlink broadcast VLC with multiple users, the SNRs of all users are different in a layout of C-LEDs. It is difficult to find a proper layout of C-LEDs to guarantee the BER of all users. To solve this problem, we propose an evolutionary algorithm (EA)-based scheme to optimize the SNR. The simulation results show that it is an effective method to improve SNR by selecting C-LEDs.

  19. [Analysis and experimental verification of sensitivity and SNR of laser warning receiver].

    PubMed

    Zhang, Ji-Long; Wang, Ming; Tian, Er-Ming; Li, Xiao; Wang, Zhi-Bin; Zhang, Yue

    2009-01-01

    In order to countermeasure increasingly serious threat from hostile laser in modern war, it is urgent to do research on laser warning technology and system, and the sensitivity and signal to noise ratio (SNR) are two important performance parameters in laser warning system. In the present paper, based on the signal statistical detection theory, a method for calculation of the sensitivity and SNR in coherent detection laser warning receiver (LWR) has been proposed. Firstly, the probabilities of the laser signal and receiver noise were analyzed. Secondly, based on the threshold detection theory and Neyman-Pearson criteria, the signal current equation was established by introducing detection probability factor and false alarm rate factor, then, the mathematical expressions of sensitivity and SNR were deduced. Finally, by using method, the sensitivity and SNR of the sinusoidal grating laser warning receiver developed by our group were analyzed, and the theoretic calculation and experimental results indicate that the SNR analysis method is feasible, and can be used in performance analysis of LWR.

  20. 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).

  1. Nonuniform expansion and brightening of the youngest Galactic SNR G1.9+0.3

    NASA Astrophysics Data System (ADS)

    Borkowski, Kazimierz

    2014-09-01

    We propose a 400-ks observation of the youngest Galactic supernova remnant (SNR) G1.9+0.3, to study its nonuniform expansion and monitor increase in brightness. Expansion along the major axis of G1.9+0.3 has been found to decrease with radius. The longer time baseline should help in understanding these surprising variations in expansion. No other Galactic SNR is brightening. The X-rays are mainly produced as synchrotron radiation from 10 -- 100 TeV electrons, so the magnitude and spatial dependence of the brightening rate have important implications for the physics of particle acceleration and magnetic-field amplification in fast shock waves. G1.9+0.3 is a unique SNR whose continued monitoring should greatly advance our understanding of Type Ia supernovae and nonthermal shock physics.

  2. 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

  3. Sea level measurements from inverse modelling of GNSS SNR data - initial results

    NASA Astrophysics Data System (ADS)

    Strandberg, Joakim; Hobiger, Thomas; Haas, Rüdiger

    2016-04-01

    The idea that sea level measurements could be done passively using available GNSS signals was proposed already over two decades ago. Since then several methods of using GNSS signals for measuring sea level have been proposed, using various degrees of specialized equipment. We present a new method to retrieve sea level from GNSS SNR data that relies upon inverse modelling of the detrended SNR data from a single off-the-shelf geodetic GNSS receiver. This method can simultaneously use SNR data from both GPS and GLONASS, and both L1 and L2 frequencies, in order to improve the performance with respect to prior studies. Results from the GNSS-R installation at the Onsala Space Observatory are presented and the retrieved sea level results are compared with data collected by a co-located pressure mareograph. The new method is found to give an RMS error of 1.8 cm. The results are also compared against previous implementations of GNSS tide gauges and found to have lower RMS than both the earlier SNR algorithm and also the dual receiver, phase delay method. This shows that inverse modelling for sea level retrieval has a potential to increase the precision of GNSS-R tide gauges, without the need for specialized equipment. Furthermore, since the method is based on SNR analysis, it can continue to operate during high winds and large sea roughness, in which the dual-receiver phase delay algorithm fails since the receiver connected to the nadir looking antenna does not succeed to lock on the satellites signals. This leads to a more stable and reliable operation. The ability to simultaneously use SNR data from different GNSS systems is also seen as a factor to increase the performance, further reducing the RMS. Therefore, in the future it is of interest to add further GNSS systems, such as Galileo and BeiDou.

  4. 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.

  5. 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

  6. Diodes stabilize LED output

    NASA Technical Reports Server (NTRS)

    Deters, R. A.

    1977-01-01

    Small-signal diodes are placed in series with light-emitting diodes (LED's) to stabilize LED output against temperature fluctuations. Simple inexpensive method compensates for thermal fluctuations over a broad temperature range. Requiring few components, technique is particularly useful where circuit-board space is limited.

  7. Hearing aid malfunction detection system

    NASA Technical Reports Server (NTRS)

    Kessinger, R. L. (Inventor)

    1977-01-01

    A malfunction detection system for detecting malfunctions in electrical signal processing circuits is disclosed. Malfunctions of a hearing aid in the form of frequency distortion and/or inadequate amplification by the hearing aid amplifier, as well as weakening of the hearing aid power supply are detectable. A test signal is generated and a timed switching circuit periodically applies the test signal to the input of the hearing aid amplifier in place of the input signal from the microphone. The resulting amplifier output is compared with the input test signal used as a reference signal. The hearing aid battery voltage is also periodically compared to a reference voltage. Deviations from the references beyond preset limits cause a warning system to operate.

  8. 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.

  9. 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).

  10. 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

  11. SNR analysis and Hadamard mask modification of DMD Hadamard Transform Near-Infrared spectrometer

    NASA Astrophysics Data System (ADS)

    Xu, Jia-lin; Liu, Hua; Lin, Chun-bo; Sun, Qiang

    2017-01-01

    The noise of Hadamard Transform (HT) Near Infrared (NIR) spectrometer includes not only the detector circuit noise but also the illumination noise. Hadamard Transform reduces the detector noise while increases the illumination noise. If the relative power intensity is large, the noise of Hadamard method will be greater than that of scanning method. This will lose the significance of Hadamard Transform. In this paper the SNRs of the Hadamard method and scanning method are analyzed. The condition of boosting SNR of spectrometer by Hadamard transform is given. When the condition is not matched, a Hadamard mask of variable height stripes is proposed which the SNR of Hadamard method can be improved. In this paper a HT NIR spectrometer based on 0.45-inch DMD is designed with the spectrum range from 1350 nm to 2500 nm. Several experiments are done with the designed spectrometer. It is shown that with the Hadamard mask of variable height stripes the average SNR is improved by a factor of 2.2 at the short wavelength band and by a factor of 2.8 on the long wavelength band, and the minimum SNR on the whole wavelength band is improved by a factor of 2.3.

  12. Simulation of Cosmic Ray Acceleration, Propagation and Interaction in SNR Environment

    NASA Astrophysics Data System (ADS)

    Lee, S. H.; Kamae, T.; Ellison, D. C.

    2007-07-01

    Recent studies of young supernova remnants (SNRs) with Chandra, XMM, Suzaku and HESS have revealed complex morphologies and spectral features of the emission sites. The critical question of the relative importance of the two competing gamma-ray emission mechanisms in SNRs; inverse-Compton scattering by high-energy electrons and pion production by energetic protons, may be resolved by GLAST-LAT. To keep pace with the improved observations, we are developing a 3D model of particle acceleration, diffusion, and interaction in a SNR where broad-band emission from radio to multi-TeV energies, produced by shock accelerated electrons and ions, can be simulated for a given topology of shock fronts, magnetic field, and ISM densities. The 3D model takes as input, the particle spectra predicted by a hydrodynamic simulation of SNR evolution where nonlinear diffusive shock acceleration is coupled to the remnant dynamics (e.g., Ellison, Decourchelle & Ballet; Ellison & Cassam-Chenai Ellison, Berezhko & Baring). We will present preliminary models of the Galactic Ridge SNR RX J1713-3946 for selected choices of SNR parameters, magnetic field topology, and ISM density distributions. When constrained by broad-band observations, our models should predict the extent of coupling between spectral shape and morphology and provide direct information on the acceleration efficiency of cosmic-ray electrons and ions in SNRs.

  13. PERFORMANCE EVALUATION OF A 32-ELEMENT HEAD ARRAY WITH RESPECT TO THE ULTIMATE INTRINSIC SNR

    PubMed Central

    Lattanzi, Riccardo; Grant, Aaron K.; Polimeni, Jonathan R.; Ohliger, Michael A.; Wiggins, Graham C.; Wald, Lawrence L.; Sodickson, Daniel K.

    2010-01-01

    The quality of an RF detector coil design is commonly judged on how it compares with other coil configurations. The aim of this article is to develop a tool for evaluating the absolute performance of RF coil arrays. An algorithm to calculate the ultimate intrinsic signal-to-noise ratio (SNR) was implemented for a spherical geometry. The same imaging tasks modeled in the calculations were reproduced experimentally using a 32-element head array. Coil performance maps were then generated based on the ratio of experimentally measured SNR to the ultimate intrinsic SNR, for different acceleration factors associated with different degrees of parallel imaging. The relative performance in all cases was highest near the center of the samples (where the absolute SNR was lowest). The highest performance was found in the unaccelerated case and a maximum of 85% was observed with a phantom whose electrical properties are consistent with values in the human brain. The performance remained almost constant for 2-fold acceleration, but deteriorated at higher acceleration factors, suggesting that larger arrays are needed for effective highly-accelerated parallel imaging. The method proposed here can serve as a tool for the evaluation of coil designs, as well as a tool to guide the development of original designs which may begin to approach the optimal performance. PMID:19904727

  14. 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.

  15. Keyboard With Voice Output

    NASA Technical Reports Server (NTRS)

    Huber, W. C.

    1986-01-01

    Voice synthesizer tells what key is about to be depressed. Verbal feedback useful for blind operators or where dim light prevents sighted operator from seeing keyboard. Also used where operator is busy observing other things while keying data into control system. Used as training aid for touch typing, and to train blind operators to use both standard and braille keyboards. Concept adapted to such equipment as typewriters, computers, calculators, telephones, cash registers, and on/off controls.

  16. 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.

  17. Climate Model Output Rewriter

    SciTech Connect

    Taylor, K. E.; Doutriaux, C.

    2004-06-21

    CMOR comprises a set of FORTRAN 90 dunctions that can be used to produce CF-compliant netCDF files. The structure of the files created by CMOR and the metadata they contain fulfill the requirements of many of the climate community’s standard model experiments (which are referred to here as "MIPS", which stands for "model intercomparison project", including, for example, AMIP, CMIP, CFMIP, PMIP, APE, and IPCC scenario runs), CMOR was not designed to serve as an all-purpose wfiter of CF-compliant netCDF files, but simply to reduce the effort required to prepare and manage MIP data. Although MIPs encourage systematic analysis of results across models, this is only easy to do if the model output is written in a common format with files structured similarly and with sufficient metadata uniformly stored according to a common standard. Individual modeling groups store their data in different ways. but if a group can read its own data with FORTRAN, then it should easily be able to transform the data, using CMOR, into the common format required by the MIPs, The adoption of CMOR as a standard code for exchanging climate data will facilitate participation in MIPs because after learning how to satisfy the output requirements of one MIP, it will be easy to prepare output for the other MIPs.

  18. Task specific evaluation of clinical full field digital mammography systems using the Fourier definition of the Hotelling observer SNR

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Badano, Aldo; Benevides, Luis; Chakrabarti, Kish; Kaczmarek, Richard V.; Kyprianou, Iacovos S.

    2010-04-01

    Pixel Signal to Noise Ratio (SNR) is a commonly used clinical metric for evaluating mammography. However, we showed in this paper, the pixel SNR can produce misleading system detectability when image processing is utilized. We developed a simple, reliable and clinically applicable methodology to evaluate mammographic imaging systems using a task SNR that accounts for the imaging system performance in the presence of the patient. We used the Hotelling observer method in spatial frequency domain to calculate the task SNR of small disk test objects embedded in the breast tissue-equivalent series (BRTES) phantom for GE Senographe DS Full Field Digital Mammography (FFDM) system. The results were compared to the calculation of pixel SNR. We calculated the Hotelling observer SNR by estimating the generalized modulation transfer function (GMTF), generalized normalized noise power spectrum (GNNPS) and generalized noise equivalent quanta (GNEQ) in the presence of the breast phantom. The task SNR we calculated increased with the square root of the exposure as expected. Furthermore, we showed that the method is stable under image processing. The task SNR is a more reliable method for evaluating the performance of imaging systems especially under realistic clinical conditions where patient equivalent phantoms or image processing is used.

  19. Numerical MHD modelling of composite SNR: The effect of pulsar birth period on pulsar wind parameters

    NASA Astrophysics Data System (ADS)

    de Jager, Ocker

    The γ-ray flux Fγ of a pulsar wind nebula in the GLAST/LAT domain can be shown to depend 2 on the pulsar birth period P0 as Fγ ∝ 1/P0 . Furthermore, it is also known that the PWN size depends on P0 , with the PWN radius overtaking the SNR forward shock if P0 is in the few millisecond domain. Whereas this is an interesting field of study, longer birth periods lead to slower PWN expansion, in which case the reverse shock compresses the PWN, One can therefore follow the time history of adiabatic losses versus adiabatic heating, which is important for multiwavelength modelling. We model composite SNRs as the time evolution of a PWN with its associated SNR forward/reverse shock and reflection wave. The effect of magnetic field is included via Faraday's induction equation. A high resolution numerical simulation scheme is followed whereby the explosion of a SNR with total explosion energy Esnr , ejecta mass Mej , ISM density ρISM and PWN energy via its pulsar birth period P0 , are followed through the Euler equations, describing inviscid flow. They are solved giving ρi (density), vi (velocity) and Pi (the pressure) with time. These equations correspond to the Navier-Stokes equations with zero viscosity and heat conduction terms. They describe the balance of mass, momentum and energy of different fluids, e.g. i = 1, 2, 3, ... and the interaction between these fluids are described by a source term Q(t), which, in the case of the PWN, is described by the spindown of the pulsar. We consider a two fluid scenario with non-relativistic (SNR) and relativistic (PWN) speeds (i = 1, 2), i.e. adiabatic indices of 5/3 and 4/3 respectively. The compressed ISM magnetic field is calculated through Faraday's Law. Note however that this is not a full MHD treatment since no backreaction on the fluid is considered. For the SNR we only consider the field of the ISM which gets compressed as the ISM is swept-up by the forward shock of the SNR. The same induction equation is also used to

  20. Hearing Aids

    MedlinePlus

    ... hair cells (outer and inner rows). When the vibrations move through this fluid, the tiny outer hair ... ear to the brain. Hearing aids intensify sound vibrations that the damaged outer hair cells have trouble ...

  1. Teaching Aids

    ERIC Educational Resources Information Center

    Barnard, W. Robert, Ed.

    1976-01-01

    Provides evaluations of several aids for teaching chemistry. Included are The Use of Chemical Abstracts, Practical Technical Writing, Infrared Spectroscopy Programs, and a film titled "You Can't Go Back." (RH)

  2. Fabrication of intermediate heat exchangers, steam generators, and sodium pumps for SNR-300

    SciTech Connect

    Van't Hoft, A.J.; DeJong, J.J.; Vroom, J.P.; Kupers, G.R.

    1987-09-01

    The sodium pumps, intermediate heat exchangers, and steam generators for the liquid-metal fast breeder reactor (LMFBR) SNR-300 were delivered by Neratoom and its industrial partners Royal Schelde and Stork Boilers. All main components were delivered to and erected in the plant between 1983 and 1085 after a long period of delay, caused mainly by continuously changing requirements with respect to the latest state-of-the-art construction and design. It is therefore concluded that to realize an effective manufacturing of breeder components an authorized and final specification is absolutely necessary. After the legal formalization of the licensing step Teilgenehmigung 7/5, it was hardly possible to further change the specification of the SNR-300 components.

  3. 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

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

    PubMed

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

    2015-07-28

    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.

  5. Depolarization ratio, SNR estimation, and polarization sensitivity analysis for a commercial Raman depolarization lidar system

    NASA Astrophysics Data System (ADS)

    Avdikos, George; Georgoussis, George

    2016-05-01

    In this paper we focus on the estimation of the Signal-to-Noise (SNR) ratio of a 3-channel commercial (Raymetics) volcanic ash detection system, (LR111-D300), already operating in UK, and also, we perform a basic lidar polarization sensitivity analysis. The results show that SNR values are higher than 10 for ranges up to 13 km for daytime conditions. This is a quite good result compared with other values presented in bibliography and prove that such system is able to detect volcanic ash detection over a range of 20 km. We also assess the lidar polarization sensitivity and then, we estimate the linear depolarization ratio. By careful choice of the optical components (emitting and receiving optics), it has been shown that uncertainties of polarization states at receiver (and thus too depolarization ratio estimation) can be much reduced.

  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. Increased SNR Efficiency in Velocity Selective Arterial Spin Labeling using Multiple Velocity Selective Saturation Modules (mm-VSASL)

    PubMed Central

    Guo, Jia; Wong, Eric C.

    2014-01-01

    Purpose Velocity-selective arterial spin labeling (VSASL) is theoretically insensitive to transit delay (TD) effects. However, it uses saturation instead of inversion, resulting in compromised signal to noise ratio (SNR). In this study we explore the use of multiple velocity-selective saturation (VSS) modules in VSASL (mm-VSASL) to improve SNR. Methods Theoretical SNR efficiency improvement and optimized parameters were calculated from simulations for mm-VSASL. VSASL with two VSS modules (VSASL-2VSS) was implemented to measure cerebral blood flow in vivo, compared with conventional VSASL (VSASL-1VSS), Pulsed ASL and Pseudo-Continuous ASL. TDs and bolus durations (BDs) were measured to validate the simulations and to examine the TD sensitivity of these preparations. Results Compared with VSASL-1VSS, VSASL-2VSS achieved a significant improvement of SNR (22.1 ± 1.9%, P = 1.7 × 10−6) in vivo, consistent with a 22.7% improvement predicted from simulations. The SNR was comparable to or higher (in GM, P = 4.3 × 10−3) than that using PCASL. VSASL was experimentally verified to have minimal TD effects. Conclusion Utilizing multiple VSS modules can improve the SNR efficiency of VSASL. Mm-VSASL may result in an SNR that is comparable to or even higher than that of PCASL in applications where long PLDs are required. PMID:25251933

  8. 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.

  9. 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.

  10. Observations of SNR RX J1713.7-3946 with H.E.S.S

    SciTech Connect

    Berge, D.; Funk, S.; Hinton, J.; Lemoine-Goumard, M.

    2005-02-21

    The shell-type supernova remnant (SNR) RX J1713.7-3946 (G347.3-0.5) was discovered with ROSAT in X-rays and later claimed as source of TeV {gamma}-rays. This object, together with several other southern hemisphere SNRs, is a prime target for observations with the High Energy Stereoscopic System (H.E.S.S.), a new system of imaging atmospheric Cherenkov telescopes which was completed at the end of 2003 in Namibia and is now in full operation. Here we report on observations of the SNR RX J1713.7-3946 which have been performed during the construction and commissioning of the H.E.S.S. system (data originally published here). We confirm TeV emission from this source and present the first ever {gamma}-ray image of an astronomical object resolved on arc minute scales. This image shows shell morphology similar to that seen in X-rays, however at photon energies some nine orders of magnitude higher. The characteristics of the energy spectrum imply efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

  11. HIV/AIDS - resources

    MedlinePlus

    Resources - HIV/AIDS ... The following organizations are good resources for information on AIDS : AIDS.gov -- www.aids.gov AIDS Info -- aidsinfo.nih.gov The Henry J. Kaiser Family Foundation -- www. ...

  12. Types of Hearing Aids

    MedlinePlus

    ... Devices Consumer Products Hearing Aids Types of Hearing Aids Share Tweet Linkedin Pin it More sharing options ... some features for hearing aids? What are hearing aids? Hearing aids are sound-amplifying devices designed to ...

  13. Experimental Results: Detection and Tracking of Low SNR Sinusoids Using Real-Time LMS and RLS Lattice Adaptive Line Enhancers.

    DTIC Science & Technology

    1991-08-01

    DETECTION AND TRACKING OF LOW SNR SINUSOIDS USING REAL-TIMNE LMS AND RI S LATTIICE, ADAPTIVE LINE PR: SSWh ENHANCRS RE: 0300000liN 6 AIJTHCRISI WVl: D68...RESULTS: DETECTION AND TRACKING OF LOW SNR SINUSOIDS USING REAL-TIME LMS AND RLS LATTICE ADAPTIVE LINE ENHANCERS i f. Terence R. Albert, Hana Abusalem...obtained from a real-time custom hardware SNR sinusoids and filter parameters such as system using 32-bit IEEE floating point filter length, and adaption

  14. Fiscal output data produce versatile graphic-numeric charts

    NASA Technical Reports Server (NTRS)

    Powell, R. W.; Romo, J. J.

    1971-01-01

    Refined computerized plotting system produces low-cost graphic-numeric charts that illustrate fiscal data on monthly incremental or cumulative basis, or both. Output is in the form of hard copy or microfilm, or visual-aid transparencies prepared from hard copy for rapid management status presentations.

  15. "Aid Like a Paycheck: Engaging with Policymakers and Practitioners to Evaluate and Improve Financial Aid"

    ERIC Educational Resources Information Center

    Weissman, Evan; O'Connell, Jesse

    2016-01-01

    "Aid Like A Paycheck" is a large-scale pilot evaluation of whether an innovative approach to disbursing financial aid can improve academic and financial outcomes for low-income community college students. Lessons from the pilot evaluation were used to create and fine-tune a logic model depicting activities, outputs, mediators, and…

  16. Effect of hearing aid release time and presentation level on speech perception in noise in elderly individuals with hearing loss.

    PubMed

    Pottackal Mathai, Jijo; Mohammed, Hasheem

    2017-02-01

    To investigate the effect of compression time settings and presentation levels on speech perception in noise for elderly individuals with hearing loss. To compare aided speech perception performance in these individuals with age-matched normal hearing subjects. Twenty (normal hearing) participants within the age range of 60-68 years and 20 (mild-to-moderate sensorineural hearing loss) in the age range of 60-70 years were randomly recruited for the study. In the former group, SNR-50 was determined using phonetically balanced sentences that were mixed with speech-shaped noise presented at the most comfortable level. In the SNHL group, aided SNR-50 was determined at three different presentation levels (40, 60, and 80 dB HL) after fitting binaural hearing aids that had different compression time settings (fast and slow). In the SNHL group, slow compression time settings showed significantly better SNR-50 compared to fast release time. In addition, the mean of SNR-50 in the SNHL group was comparable to normal hearing participants while using a slow release time. A hearing aid with slow compression time settings led to significantly better speech perception in noise, compared to that of a hearing aid that had fast compression time settings.

  17. Mammalian clock output mechanisms.

    PubMed

    Kalsbeek, Andries; Yi, Chun-Xia; Cailotto, Cathy; la Fleur, Susanne E; Fliers, Eric; Buijs, Ruud M

    2011-06-30

    In mammals many behaviours (e.g. sleep-wake, feeding) as well as physiological (e.g. body temperature, blood pressure) and endocrine (e.g. plasma corticosterone concentration) events display a 24 h rhythmicity. These 24 h rhythms are induced by a timing system that is composed of central and peripheral clocks. The highly co-ordinated output of the hypothalamic biological clock not only controls the daily rhythm in sleep-wake (or feeding-fasting) behaviour, but also exerts a direct control over many aspects of hormone release and energy metabolism. First, we present the anatomical connections used by the mammalian biological clock to enforce its endogenous rhythmicity on the rest of the body, especially the neuro-endocrine and energy homoeostatic systems. Subsequently, we review a number of physiological experiments investigating the functional significance of this neuro-anatomical substrate. Together, this overview of experimental data reveals a highly specialized organization of connections between the hypothalamic pacemaker and neuro-endocrine system as well as the pre-sympathetic and pre-parasympathetic branches of the autonomic nervous system.

  18. Gain and offset calibration reduces variation in exposure-dependent SNR among systems with identical digital flat-panel detectors

    SciTech Connect

    Willis, Charles E.; Vinogradskiy, Yevgeniy Y.; Lofton, Brad K.; White, R. Allen

    2011-07-15

    Purpose: The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging. Methods: The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 {mu}Gy air KERMA) to the detector. Results: The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r{sup 2} = 0.9999). The dependence was greater than unity (m = 1.101 {+-} 0.006), and the difference from unity was statistically significant (p < 0.005). The SD of mean SNR after calibration also

  19. Classroom Aids

    ERIC Educational Resources Information Center

    Science Activities: Classroom Projects and Curriculum Ideas, 2007

    2007-01-01

    This article describes 6 aids for science instruction, including (1) the use of fudge to represent lava; (2) the "Living by Chemistry" program, designed to make high school chemistry more accessible to a diverse pool of students without sacrificing content; (3) NOAA and NSTA's online coral reef teaching tool, a new web-based "science toolbox" for…

  20. Floriculture Aide.

    ERIC Educational Resources Information Center

    Martin, Joyce; Looney, Era

    Designed for use in a self-paced, open-entry/open-exit vocational training program for a floriculture aide, this program guide is one of six for teachers of adult women offenders from a correctional institution. Module topic outlines and sample lesson plans are presented on eleven topics: occupational opportunities in the retail florist industry;…

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Maggi, Pierre; Acero, Fabio

    2017-01-01

    Aims: We present a study of the Galactic supernova remnant SNR G15.9+0.2 with archival XMM-Newton observations. Methods: EPIC data are used to investigate the morphological and spectral properties of the remnant, searching in particular for supernova ejecta and Fe K line emission. By comparing the SNR's X-ray absorption column density with the atomic and molecular gas distribution along the line of sight, we attempt to constrain the distance to the SNR. Results: Prominent line features reveal the presence of ejecta. Abundance ratios of Mg, Si, S, Ar, and Ca strongly suggest that the progenitor of SNR G15.9+0.2 was a massive star with a main sequence mass likely in the range 20-25 M⊙, strengthening the physical association with a candidate central compact object detected with Chandra. Using EPIC's collective power, Fe K line emission from SNR G15.9+0.2 is detected for the first time. We measure the line properties and find evidence for spatial variations. We discuss how the source fits within the sample of SNRs with detected Fe K emission and find that it is the core-collapse SNR with the lowest Fe K centroid energy. We also present some caveats regarding the use of Fe K line centroid energy as a typing tool for SNRs. Only a lower limit of 5 kpc is placed on the distance to SNR G15.9+0.2, constraining its age to tSNR ≳ 2 kyr.

  3. 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.

  4. 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.

  5. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  6. 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).

  7. Quantization of Gaussian samples at very low SNR regime in continuous variable QKD applications

    NASA Astrophysics Data System (ADS)

    Daneshgaran, Fred; Mondin, Marina

    2016-09-01

    The main problem for information reconciliation in continuous variable Quantum Key Distribution (QKD) at low Signal to Noise Ratio (SNR) is quantization and assignment of labels to the samples of the Gaussian Random Variables (RVs) observed at Alice and Bob. Trouble is that most of the samples, assuming that the Gaussian variable is zero mean which is de-facto the case, tend to have small magnitudes and are easily disturbed by noise. Transmission over longer and longer distances increases the losses corresponding to a lower effective SNR exasperating the problem. This paper looks at the quantization problem of the Gaussian samples at very low SNR regime from an information theoretic point of view. We look at the problem of two bit per sample quantization of the Gaussian RVs at Alice and Bob and derive expressions for the mutual information between the bit strings as a result of this quantization. The quantization threshold for the Most Significant Bit (MSB) should be chosen based on the maximization of the mutual information between the quantized bit strings. Furthermore, while the LSB string at Alice and Bob are balanced in a sense that their entropy is close to maximum, this is not the case for the second most significant bit even under optimal threshold. We show that with two bit quantization at SNR of -3 dB we achieve 75.8% of maximal achievable mutual information between Alice and Bob, hence, as the number of quantization bits increases beyond 2-bits, the number of additional useful bits that can be extracted for secret key generation decreases rapidly. Furthermore, the error rates between the bit strings at Alice and Bob at the same significant bit level are rather high demanding very powerful error correcting codes. While our calculations and simulation shows that the mutual information between the LSB at Alice and Bob is 0.1044 bits, that at the MSB level is only 0.035 bits. Hence, it is only by looking at the bits jointly that we are able to achieve a

  8. 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

  9. Inverter communications using output signal

    DOEpatents

    Chapman, Patrick L.

    2017-02-07

    Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

  10. HIV/AIDS Basics

    MedlinePlus

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  11. First Results from a Principal Component Analysis of Tycho's SNR: Evidence for Cosmic Ray Ion Acceleration

    NASA Astrophysics Data System (ADS)

    Warren, J. S.; Hughes, J. P.; Badenes, C.

    2005-12-01

    We present results from a Principal Component Analysis (PCA) of Tycho's supernova remnant (SNR). PCA is a statistical technique we implemented to characterize X-ray spectra extracted from distinct spatial regions across the entire image of the remnant. We used the PCA to determine the location of the contact discontinuity (CD) in Tycho, which marks the boundary between shocked ejecta and shocked interstellar material, and found an azimuthal-angle-averaged radius of 241". For the average radius of the outer blast wave (BW) we found 251". Taking account of projection effects, the ratio of BW:CD is 1:0.93, which is inconsistent with adiabatic hydrodynamic models of SNR evolution. The BW:CD ratio can be explained if cosmic ray acceleration of ions is occurring at the forward shock. Such a scenario is further supported by evidence from the morphology and spectral nature of the BW emission for the acceleration of cosmic ray electrons. We also present PCA results regarding the ranges in Si and Fe composition in Tycho, and a newly uncovered spectral variation in the form of a low energy excess that has not been previously noted.

  12. 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.

  13. 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.

  14. 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.

  15. [Equalization of whole-band signal's SNR in the blood components noninvasive measurement].

    PubMed

    Li, Gang; Wang, Hui-quan; Zhang, Hao; Lin, Ling; Wu, Xiao-rong; Zhang, Bao-ju

    2012-02-01

    To fully extend the category of blood components that can be noninvasively measured by dynamic spectrum (DS) method and to increase its measuring precision, an overall consideration of light source, tissue absorption and sensor's sensitivity was made. Compensating the light source and adding the telecentric lens not only expand the spectral effective detecting range, but also balance the signal-to-noise ratio (SNR) of the photoelectric pulse in the whole band equalization. The integral SNR of DS signal was increased and the measurement bandwidth was expanded. The effectiveness of this method was validated by the quality evaluation criterion of DS data: the effective detecting range of visible DS was widened from 600-1 000 nm to 500-1 135 nm; the effective detecting range of near-infrared DS was widened from 900-1 100 nm to 900-1 700 nm. The results show that the design can create the condition for detection of new blood components noninvasively, and enhance the prediction accuracy of the blood components, for which noninvasive measuring using DS method has been achieved.

  16. Ejecta in the Oxygen-Rich SNR G292.0+1.8

    NASA Astrophysics Data System (ADS)

    Winkler, P. F.; Long, K. S.

    2004-08-01

    New optical images of the young supernova remnant (SNR) G292.0+1.8, obtained from the 0.9-m telescope at CTIO, show a far more extensive network of filaments than previous data suggest. Images in [O III] show filaments distributed throughout much of the 8 arcmin diameter shell seen in X-ray and radio images. Most of the outer filaments have a radial, pencil-like morphology that is very suggestive of Rayleigh-Tayor fingers. Simulations of core-collapse supernovae predict the development of such fingers, but they have never before been so clearly observed in a young SNR. In addition to the extensive [O III] filaments, we have detected three small complexes of filaments that show [S II] emission along with the oxygen lines. None of the filaments, with or without [S II], show any evidence for hydrogen, so all must be composed of pure supernova ejecta. The [S II] filaments provide the first evidence for products of oxygen burning in the ejecta from the event that gave rise to G292.0+1.8. This research has been funded primarily by the National Science Foundation through grant AST-0307613.

  17. Proper Motions in the SNR RCW86 and the Guest Star of 185AD

    NASA Astrophysics Data System (ADS)

    Kamper, K. W.; van den Bergh, S.; Westerlund, B.

    1995-03-01

    The guest star, apparently in Centaurus, which was observed in China in the year 185AD has usually been identified with the SNR RCW86 (alias MSH 14-63). An alternative possibility (Thorsett, Nature 356, 690, 1992) is the pulsar PSR 1509-58 whose spin-down age of 1700 years is suggestively appropriate. On the other hand, the nebula, RCW89, which coincides with that pulsar shows no significant internal proper motion and so is unlikely to be a young object (van den Bergh and Kamper, ApJ 280, L51, 1984). We have now made a proper motion study of optically brightest region of the prime candidate RCW86 using plates from the Radcliff 1.9m taken in 1963 and the CTIO 4m taken in 1977 along with CCD frames from the UTSO 0.6m obtained in 1990 and 1993. The observed arc is some 1100 arc seconds from the center of symmetry of the radio source. If the nebula is in the Sedov adiabatic phase of expansion, the expected proper motion would be 0.24 arc sec yr(-1) . Our measured values are more than an order of magnitude smaller and thus contradict the hypothesis of youth for this SNR. Disappointingly, the 185AD object may indeed have been merely a comet (Chin and Huang, Nature 311, 29, 1994) unless it was indeed a supernova that produced a pulsar without producing a nebular remnant.

  18. High spatial resolution spectroscopy of Tycho’s SNR with Chandra

    NASA Astrophysics Data System (ADS)

    Guo, Yun-Dong; Yang, Xue-Juan

    2017-02-01

    We present high spatial resolution X-ray spectroscopy of Tycho’s supernova remnant (SNR) using observational data from Chandra. The whole remnant was divided into 26 × 27 regions, with each of them covering 20\\prime\\prime × 20\\prime\\prime. We selected 536 pixels with enough events to generate spectra and fit them with an absorbed two component non-equilibrium ionization model. We obtained maps of absorbing column density, weight-averaged temperature, ionization age and abundances for O, Ne, Mg, Si, S and Fe, with emission used to determine the weight. The abundance maps and the finding that Fe abundance is not correlated with any other element suggest that Fe is located at a smaller radius than other elements, supporting the onion shell model with emission from more massive elements peaking more toward the center. A tight correlation between Si and S abundances support both Si and S coming from explosive O-burning and/or incomplete Si-burning. O and Ne abundances show no correlation with any other element. Considering that O, Ne and Mg are all synthesized in the same process (C/Ne-burning), we suggest that O/Ne/Mg might mix well with other elements during the explosion of the supernova and the expansion of the SNR.

  19. Multi-Reception Strategy with Improved SNR for Multichannel MR Imaging

    PubMed Central

    Wu, Bing; Li, Ye; Wang, Chunsheng; Vigneron, Daniel B.; Zhang, Xiaoliang

    2012-01-01

    A multi-reception strategy with extended GRAPPA is proposed in this work to improve MR imaging performance at ultra-high field MR systems with limited receiver channels. In this method, coil elements are separated to two or more groups under appropriate grouping criteria. Those groups are enabled in sequence for imaging first, and then parallel acquisition is performed to compensate for the redundant scan time caused by the multiple receptions. To efficiently reconstruct the data acquired from elements of each group, a specific extended GRAPPA was developed. This approach was evaluated by using a 16-element head array on a 7 Tesla whole-body MRI scanner with 8 receive channels. The in-vivo experiments demonstrate that with the same scan time, the 16-element array with twice receptions and acceleration rate of 2 can achieve significant SNR gain in the periphery area of the brain and keep nearly the same SNR in the center area over an eight-element array, which indicates the proposed multi-reception strategy and extended GRAPPA are feasible to improve image quality for MRI systems with limited receive channels. This study also suggests that it is advantageous for a MR system with N receiver channels to utilize a coil array with more than N elements if an appropriate acquisition strategy is applied. PMID:22879921

  20. Simulation verification of SNR and parallel imaging improvements by ICE-decoupled loop array in MRI.

    PubMed

    Yan, Xinqiang; Cao, Zhipeng; Zhang, Xiaoliang

    2016-04-01

    Transmit/receive L/C loop arrays with the induced current elimination (ICE) or magnetic wall decoupling method has shown high signal-to-noise (SNR) and excellent parallel imaging ability for MR imaging at ultrahigh fields, e.g., 7 T. In this study, we aim to numerically analyze the performance of an eight-channel ICE-decoupled loop array at 7 T. Three dimensional (3-D) electromagnetic (EM) and radiofrequency (RF) circuit co-simulation approach was employed. The values of all capacitors were obtained by optimizing the S-parameters of all coil elements. The EM simulation accurately modeled the coil structure, the phantom and the excitation. All coil elements were well matched to 50 ohm and the isolation between any two coil elements was better -15 dB. The simulated S parameters were exactly similar with the experimental results, indicating the simulation results were reliable. Compared with the conventional capacitively decoupled array, the ICE-decoupled array had higher sensitivity at the peripheral areas of the image subjects due to the shielding effect of the decoupling loops. The increased receive sensitivity resulted in an improvement of signal intensity and SNR for the ICE-decoupled array.

  1. SKE/BKE task-based methodology for calculating Hotelling observer SNR in mammography

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Kyprianou, Iacovos S.; Badano, Aldo; Myers, Kyle J.; Jennings, Robert J.; Park, Subok; Kaczmarek, Richard V.; Chakrabarti, Kish

    2009-02-01

    A common method for evaluating projection mammography is Contrast-Detail (CD) curves derived from the CD phantom for Mammography (CDMAM). The CD curves are derived either by human observers, or by automated readings. Both methods have drawbacks which limit their reliability. The human based reading is significantly affected by reader variability, reduced precision and bias. On the other hand, the automated methods suffer from limited statistics. The purpose of this paper is to develop a simple and reliable methodology for the evaluation of mammographic imaging systems using the Signal Known Exactly/Background Known Exactly (SKE/BKE) detection task for signals relevant to mammography. In this paper, we used the spatial definition of the ideal, linear (Hotelling) observer to calculate the task-specific SNR for mammography and discussed the results. The noise covariance matrix as well as the detector response H matrix of the imaging system were estimated and used to calculate the SNRSKEBKE for the simulated discs of the CDMAM. The SNR as a function of exposure, disc diameter and thickness were calculated.

  2. Noise and signal detection in digital x-ray detectors using the spatial definition of SNR

    NASA Astrophysics Data System (ADS)

    Kyprianou, Iacovos S.; Badano, Aldo; Park, Subok; Liu, Haimo; Myers, Kyle J.

    2009-02-01

    For task specific evaluation of imaging systems it is necessary to obtain detailed descriptions of their noise and deterministic properties. In the past we have developed an experimental and theoretical methodology to estimate the deterministic detector response of a digital x-ray imaging system, also known as the H matrix. In this paper we have developed the experimental methodology for the evaluation of the quantum and electronic noise of digital radiographic detectors using the covariance matrix K. Using the H matrix we calculated the transfer of a simulated coronary artery constriction through an imaging system's detector, and with the covariance matrix we calculated the detectability (or Signal-to-Noise Ratio) and the detection probability. The eigenvalues and eigenvectors of the covariance matrix were presented and the electronic and quantum noise were analyzed. We found that the exposure at which the electronic noise equals the quantum noise at 90 kVp was 0.2 μR. We compared the ideal Hotelling observer with the Fourier definition of the SNR for a toroidal stenosis on a cylindrical vessel. Because of the shift-invariance and cyclo-stationarity assumptions, the Fourier SNR overestimates the performance of imaging systems. This methodology can be used for task specific evaluation and optimization of a digital x-ray imaging system.

  3. 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

  4. Study of young stellar objects around SNR G18.8+0.3

    NASA Astrophysics Data System (ADS)

    Celis Peña, M.; Paron, S.

    2016-08-01

    In recent works, through observations of molecular lines, we found that the supernova remnant (SNR) G18.8+0.3 is interacting with a molecular cloud towards its southern edge. Also it has been proven the presence of several neighboring H ii regions very likely located at the same distance as the remnant. The presence of dense molecular gas and the existence of shock fronts generated by the SNR and H ii regions make this region an interesting scenario to study the population of young stellar objects. Thus, using the most modern colour criteria applied to the emission in the mid-infrared bands obtained from IRAC and MIPS on board Spitzer, we characterized all the point sources lying in this region. We analyzed the spectral energy distributions of sources that show signs of being young stellar objects in order to confirm their nature and derive stellar parameters. Additionally, we present a map of the CO J=32 emission obtained with the ASTE telescope towards one of the H ii regions embedded in the molecular cloud. The molecular gas was studied with the aim to analyze whether the cloud is a potential site of star formation.

  5. TeV γ-ray source MGRO J2019+37 : PWN or SNR?

    NASA Astrophysics Data System (ADS)

    Saha, Lab; Bhattacharjee, Pijushpani

    2014-01-01

    Milagro has recently reported an extended TeV γ-ray source MGRO J2019+37 in the Cygnus region. It is the second brightest TeV source after Crab nebula in their source catalogue. No confirmed counterparts of this source are known although possible associations with several known sources have been suggested. We study leptonic as well as hadronic models of TeV emission within the context of Pulsar Wind Nebulae (PWN) and Supernova Remnant (SNR) type sources, using constraints from multi-wavelength data from observations made on sources around MGRO J2019+37. These include radio upper limit given by GMRT, GeV observations by Fermi-LAT, EGRET and AGILE and very high energy data taken from Milagro. We find that, within the PWN scenario, while both leptonic as well as hadronic models can explain the TeV flux from this source, the GMRT upper limit imposes a stringent upper limit on the size of the emission region in the case of leptonic model. In the SNR scenario, on the other hand, a purely leptonic origin of TeV flux is inconsistent with the GMRT upper limit. At the same time, a dominantly hadronic origin of the TeV flux is consistent with all observations, and the required hadronic energy budget is comparable to that of typical supernovae explosions.

  6. Information content of SNR/resolution trade-offs in three-dimensional magnetic resonance imaging.

    PubMed

    Portnoy, S; Kale, S C; Feintuch, A; Tardif, C; Pike, G B; Henkelman, R M

    2009-04-01

    In MRI, a trade-off exists between resolution and signal-to-noise ratio, since different fractions of the available scan time can be used to acquire data at higher spatial frequencies and to perform signal averaging. By comparing a wide variety of 3D isotropic MR scans with different combinations of SNR, resolution, and scan duration, the impact of this trade-off on the image information content was assessed. The information content of mouse brain, mouse whole-body, and human brain images was evaluated using a simple numerical approach, which sums the information contribution of each individual k-space data point. Results show that, with a fixed receiver bandwidth and field of view, the information content of trade-off images is always maximized when the SNR is equal to about 16. The optimal imaging resolution is dependent on the scan duration, as well as certain MR system properties, such as field strength and coil sensitivity. These properties are, however, easily accounted for with the acquisition of a single scout MR image, and the optimal imaging resolution can then be calculated using a simple mathematical relationship. If the imaging task is approached with a predetermined resolution requirement, the same scout scan can be used to calculate the scan duration that will provide the maximum possible information. Using these relationships to maximize the image information content is an excellent technique for guiding the initial selection of imaging parameters.

  7. SNR 1E0102.2-7219 in the Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Amy, Shaun W.

    1994-04-01

    The source 1E0102.2-7219 was first identified as a possible supernova remnant (SNR) by Seward and Mitchell (1981, Astrophys. J., 243, 736) using the Einstein observatory, on the basis of its X-ray luminosity and spectral energy distribution. It is the second brightest X-ray source in the Small Magellanic Cloud. 1E0102.2-7219 was positively identified as a supernova remnant (SNR) by Dopita et al. (1981, Astrophys. J. Lett., 248, L105) who classified it as a member of the oxygen-rich class of SNRs. Narrow-band optical imaging with the Anglo-Australian Telescope revealed a large (O III)/H alpha ratio and a strong (O III) filamentary shell only 1.5 arcmin from the quoted X-ray position. Observations made with the Australia Telescope Compact Array (ATCA) at 4790 MHz by Amy and Ball (1993, Astrophys. J., 411, 761) revealed an almost complete shell of radio emission and a compact central component which contributes about 14% of the total flux density. The angular diameter of the outer shell of radio emission is around 40 sec which is consistent with the angular diameter of the 'emission-hole' discussed by Dopita et al. (1981) and with the high-resolution X-ray data. Using the ATCA data along with previously published data at 408 MHz and 843 MHz we determined the radio spectral index to be alpha = -(0.7 +/- 0.1). The compact central component has an angular diameter of approximately 18 sec determined by taking cross-cuts through the ATCA image at various position angles. There are at least two possible interpretations of this compact component: (1) it may be a bright spot on the surface of the radio shell (front or back), in which case it probably corresponds to a region of enhanced acceleration and is of no special interest; or (2) it may be a central or core component inside the radio shell. Such core components are often referred to as 'plerions' and are thought to be associated with a remnant pulsar produced in the supernova explosion. If this is the case, then SNR 1E

  8. Enhanced performance CCD output amplifier

    DOEpatents

    Dunham, Mark E.; Morley, David W.

    1996-01-01

    A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

  9. Teaching AIDS.

    PubMed

    Short, R V

    1989-06-01

    This article reviews a peer group Acquired Immunodeficiency Syndrome (AIDS) educational program at a university in Australia. Studies in the US have shown that most adolescents, although sexually active, do not believe they are likely to become infected with the Human Immunodeficiency Virus, and therefore do not attempt to modify their sexual behavior. A 1st step in educating students is to introduce them to condoms and impress upon them the fact that condoms should be used at the beginning of all sexual relationships, whether homosexual or heterosexual. In this program 3rd year medical students were targeted, as they are effective communicators and disseminators of information to the rest of the student body. After class members blow up condoms, giving them a chance to handle various brands and observe the varying degrees of strength, statistical evidence about the contraceptive failure rate of condoms (0.6-14.7 per 100 women-years) is discussed. Spermicides, such as nonoxynol-9 used in conjunction with condoms, are also discussed, as are condoms for women, packaging and marketing of condoms, including those made from latex and from the caecum of sheep, the latter condoms being of questionable effectiveness in preventing transmission of the virus. The care of terminal AIDS cases and current global and national statistics on AIDS are presented. The program also includes cash prizes for the best student essays on condom use, the distribution of condoms, condom key rings and T-shirts, and a student-run safe sex stand during orientation week. All of these activities are intended to involve students and attract the interest of the undergraduate community. Questionnaires administered to students at the end of the course revealed that the lectures were received favorably. Questionnaires administered to new medical and English students attending orientation week revealed that 72% of students thought the stand was a good idea and 81% and 83%, respectively found it

  10. On the Equivalence of Maximum SNR and MMSE Estimation: Applications to Additive Non-Gaussian Channels and Quantized Observations

    NASA Astrophysics Data System (ADS)

    Rugini, Luca; Banelli, Paolo

    2016-12-01

    The minimum mean-squared error (MMSE) is one of the most popular criteria for Bayesian estimation. Conversely, the signal-to-noise ratio (SNR) is a typical performance criterion in communications, radar, and generally detection theory. In this paper we first formalize an SNR criterion to design an estimator, and then we prove that there exists an equivalence between MMSE and maximum-SNR estimators, for any statistics. We also extend this equivalence to specific classes of suboptimal estimators, which are expressed by a basis expansion model (BEM). Then, by exploiting an orthogonal BEM for the estimator, we derive the MMSE estimator constrained to a given quantization resolution of the noisy observations, and we prove that this suboptimal MMSE estimator tends to the optimal MMSE estimator that uses an infinite resolution of the observation. Besides, we derive closed-form expressions for the mean-squared error (MSE) and for the SNR of the proposed suboptimal estimators, and we show that these expressions constitute tight, asymptotically exact, bounds for the optimal MMSE and maximum SNR.

  11. Disentangling the hadronic from the leptonic emission in the composite SNR G326.3-1.8

    NASA Astrophysics Data System (ADS)

    Devin, J.; Acero, F.; Schmid, J.; Ballet, J.

    2016-06-01

    Supernova remnants (SNRs), pulsar wind nebulae (PWNe) and pulsars are the usual suspects to accelerate the bulk of cosmic rays in our Galaxy.In those objects the gamma-ray emission allows us to probe the population of high-energy particles and in particular the population of accelerated hadrons radiating through the pion-decay mechanism. Those Galactic accelerators are most of the time studied as independent objects, even if, in the case of some core-collapse supernovae, the shell-like SNR, the PWN and the pulsar are in fact present in the same object.In the case of composite SNRs, both the SNR shell and the PWN are bright enough to be observed in the same source. Understanding the nature of the gamma-ray emission in such objects can be challenging for sources of small angular extension. Previous studies of the composite SNR G326.3-1.8 (radius=0.3 degrees) revealed bright and extended gamma-ray emission but its origin remained uncertain.With the recent Pass8 Fermi-LAT data that provide an increased acceptance and angular resolution, we investigate the detailed morphology of this composite SNR in order to distinguish the SNR from the PWN contribution. In particular, we take advantage of the new possibility to filter events based on their angular reconstruction quality (PSF types). Disentangling the different components is crucial to clearly model the spectral properties of the source and to understand its nature.

  12. Multi-output differential technologies

    NASA Astrophysics Data System (ADS)

    Bidare, Srinivas R.

    1997-01-01

    A differential is a very old and proven mechanical device that allows a single input to be split into two outputs having equal torque irrespective of the output speeds. A standard differential is capable of providing only two outputs from a single input. A recently patented multi-output differential technology known as `Plural-Output Differential' allows a single input to be split into many outputs. This new technology is the outcome of a systematic study of complex gear trains (Bidare 1992). The unique feature of a differential (equal torque at different speeds) can be applied to simplify the construction and operation of many complex mechanical devices that require equal torque's or forces at multiple outputs. It is now possible to design a mechanical hand with three or more fingers with equal torque. Since these finger are powered via a differential they are `mechanically intelligent'. A prototype device is operational and has been used to demonstrate the utility and flexibility of the design. In this paper we shall review two devices that utilize the new technology resulting in increased performance, robustness with reduced complexity and cost.

  13. Output optics for laser velocimeters

    NASA Technical Reports Server (NTRS)

    Lynch, Dana H. (Inventor); Gunter, William D. (Inventor); Mcalister, Kenneth W. (Inventor)

    1993-01-01

    Space savings are effected in the optical output system of a laser velocimeter. The output system is comprised of pairs of optical fibers having output ends from which a beam of laser light emerges, a transfer lens for each light beam, and at least one final (LV) lens for receiving the light passing through the transfer lenses and for focussing that light at a common crossing point or area. In order to closely couple the transfer lenses to the final lens, each transfer lens is positioned relative to the final lens receiving light therefrom such that the output waist of the corresponding beam received by the final lens from the transfer lens is a virtual waist located before the transfer lens.

  14. Research on output feedback control

    NASA Technical Reports Server (NTRS)

    Calise, Anthony J.

    1988-01-01

    A summary is presented of the main results obtained during the course of research on output feedback control. The term output feedback is used to denote a controller design approach which does not rely on an observer to estimate the states of the system. Thus, the order of the controller is fixed, and can even be zero order, which amounts to constant gain ouput feedback. The emphasis has been on optimal output feedback. That is, a fixed order controller is designed based on minimizing a suitably chosen quadratic performance index. A number of problem areas that arise in this context have been addressed. These include developing suitable methods for selecting an index of performance, both time domain and frequency domain methods for achieving robustness of the closed loop system, developing canonical forms to achieve a minimal parameterization for the controller, two time scale design formulations for ill-conditioned systems, and the development of convergent numerical algorithms for solving the output feedback problem.

  15. 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.

  16. 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.

  17. Cardiac output after burn injury.

    PubMed Central

    Porter, J. M.; Shakespeare, P. G.

    1984-01-01

    Cardiac output after burn injury has been measured by the non-invasive method of impedance plethysmography. An initial study of 143 normal subjects was undertaken in order to investigate variations in cardiac output with age. Fifteen patients were monitored during resuscitation after extensive burns. Fourteen patients showed a depression of stroke volume below the lower limits of the normal range, derived from the initial study on normal people. PMID:6691694

  18. Electronic filters, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Engebretson, A. Maynard (Inventor); O'Connell, Michael P. (Inventor); Zheng, Baohua (Inventor)

    1991-01-01

    An electronic filter for an electroacoustic system. The system has a microphone for generating an electrical output from external sounds and an electrically driven transducer for emitting sound. Some of the sound emitted by the transducer returns to the microphone means to add a feedback contribution to its electical output. The electronic filter includes a first circuit for electronic processing of the electrical output of the microphone to produce a filtered signal. An adaptive filter, interconnected with the first circuit, performs electronic processing of the filtered signal to produce an adaptive output to the first circuit to substantially offset the feedback contribution in the electrical output of the microphone, and the adaptive filter includes means for adapting only in response to polarities of signals supplied to and from the first circuit. Other electronic filters for hearing aids, public address systems and other electroacoustic systems, as well as such systems, and methods of operating them are also disclosed.

  19. Electronic filters, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Engebretson, A. Maynard (Inventor)

    1995-01-01

    An electronic filter for an electroacoustic system. The system has a microphone for generating an electrical output from external sounds and an electrically driven transducer for emitting sound. Some of the sound emitted by the transducer returns to the microphone means to add a feedback contribution to its electrical output. The electronic filter includes a first circuit for electronic processing of the electrical output of the microphone to produce a first signal. An adaptive filter, interconnected with the first circuit, performs electronic processing of the first signal to produce an adaptive output to the first circuit to substantially offset the feedback contribution in the electrical output of the microphone, and the adaptive filter includes means for adapting only in response to polarities of signals supplied to and from the first circuit. Other electronic filters for hearing aids, public address systems and other electroacoustic systems, as well as such systems and methods of operating them are also disclosed.

  20. AIDS.gov

    MedlinePlus

    ... concerns. Search Services Share This Help National HIV/AIDS Strategy Check out NHAS's latest progress in the ... from AIDS.gov Read more AIDS.gov tweets AIDS.gov HIV/AIDS Basics • Federal Resources • Using New ...

  1. Kv3-like potassium channels are required for sustained high-frequency firing in basal ganglia output neurons.

    PubMed

    Ding, Shengyuan; Matta, Shannon G; Zhou, Fu-Ming

    2011-02-01

    The GABA projection neurons in the substantial nigra pars reticulata (SNr) are key output neurons of the basal ganglia motor control circuit. These neurons fire sustained high-frequency, short-duration spikes that provide a tonic inhibition to their targets and are critical to movement control. We hypothesized that a robust voltage-activated K(+) conductance that activates quickly and resists inactivation is essential to the remarkable fast-spiking capability in these neurons. Semi-quantitative RT-PCR (qRT-PCR) analysis on laser capture-microdissected nigral neurons indicated that mRNAs for Kv3.1 and Kv3.4, two key subunits for forming high activation threshold, fast-activating, slow-inactivating, 1 mM tetraethylammonium (TEA)-sensitive, fast delayed rectifier (I(DR-fast)) type Kv channels, are more abundant in fast-spiking SNr GABA neurons than in slow-spiking nigral dopamine neurons. Nucleated patch clamp recordings showed that SNr GABA neurons have a strong Kv3-like I(DR-fast) current sensitive to 1 mM TEA that activates quickly at depolarized membrane potentials and is resistant to inactivation. I(DR-fast) is smaller in nigral dopamine neurons. Pharmacological blockade of I(DR-fast) by 1 mM TEA impaired the high-frequency firing capability in SNr GABA neurons. Taken together, these results indicate that Kv3-like channels mediating fast-activating, inactivation-resistant I(DR-fast) current are critical to the sustained high-frequency firing in SNr GABA projection neurons and hence movement control.

  2. Sound quality measures for speech in noise through a commercial hearing aid implementing digital noise reduction.

    PubMed

    Ricketts, Todd A; Hornsby, Benjamin W Y

    2005-05-01

    This brief report discusses the affect of digital noise reduction (DNR) processing on aided speech recognition and sound quality measures in 14 adults fitted with a commercial hearing aid. Measures of speech recognition and sound quality were obtained in two different speech-in-noise conditions (71 dBA speech, +6 dB SNR and 75 dBA speech, +1 dB SNR). The results revealed that the presence or absence of DNR processing did not impact speech recognition in noise (either positively or negatively). Paired comparisons of sound quality for the same speech in noise signals, however, revealed a strong preference for DNR processing. These data suggest that at least one implementation of DNR processing is capable of providing improved sound quality, for speech in noise, in the absence of improved speech recognition.

  3. Crawling Aid

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Institute for the Achievement of Human Potential developed a device known as the Vehicle for Initial Crawling (VIC); the acronym is a tribute to the crawler's inventor, Hubert "Vic" Vykukal; is an effective crawling aid. The VIC is used by brain injured children who are unable to crawl due to the problems of weight-bearing and friction, caused by gravity. It is a rounded plywood frame large enough to support the child's torso, leaving arms and legs free to move. On its underside are three aluminum discs through which air is pumped to create an air-bearing surface that has less friction than a film of oil. Upper side contains the connection to the air supply and a pair of straps which restrain the child and cause the device to move with him. VIC is used with the intent to recreate the normal neurological connection between brain and muscles. Over repetitive use of the device the child develops his arm and leg muscles as well as coordination. Children are given alternating therapy, with and without the VIC until eventually the device is no longer needed.

  4. Heart attack first aid

    MedlinePlus

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 ...

  5. Buying a Hearing Aid

    MedlinePlus

    ... aids typically cannot be custom-fit. What are costs and styles of hearing aids? Hearing aids vary ... and for improvement in hearing tones. Real ear measurements may also be done, which determine how much ...

  6. Neurological Complications of AIDS

    MedlinePlus

    ... Patient & Caregiver Education » Fact Sheets Neurological Complications of AIDS Fact Sheet Table of Contents (click to jump ... Where can I get more information? What is AIDS? AIDS (acquired immune deficiency syndrome) is a condition ...

  7. HIV and AIDS

    MedlinePlus

    ... dientes Video: Getting an X-ray HIV and AIDS KidsHealth > For Kids > HIV and AIDS Print A ... serious infection. continue How Many People Have HIV/AIDS? Since the discovery of the virus in 1983, ...

  8. Speech Envelope Normalization, a Method to Improve SNR and Suppress Noise in Present and Future Radio Systems.

    DTIC Science & Technology

    1982-12-01

    2 2 2 SNRe = e (t)/n 2 (t) = 2av /an2 (69) 23 Stremler , F. G., Introduction To Communication Systems, Addison-Wesley, 1977. 74 this SNR is related to...Characteristics for Studying Intelligibility," The Journal of the Acoustical Society of America, Vol. 49, No. 6 (Part 2), 1971. * 23. Stremler , F. G., Introduction

  9. Quantifying PV power Output Variability

    SciTech Connect

    Hoff, Thomas E.; Perez, Richard

    2010-10-15

    This paper presents a novel approach to rigorously quantify power Output Variability from a fleet of photovoltaic (PV) systems, ranging from a single central station to a set of distributed PV systems. The approach demonstrates that the relative power Output Variability for a fleet of identical PV systems (same size, orientation, and spacing) can be quantified by identifying the number of PV systems and their Dispersion Factor. The Dispersion Factor is a new variable that captures the relationship between PV Fleet configuration, Cloud Transit Speed, and the Time Interval over which variability is evaluated. Results indicate that Relative Output Variability: (1) equals the inverse of the square root of the number of systems for fully dispersed PV systems; and (2) could be further minimized for optimally-spaced PV systems. (author)

  10. The Galactic plane region near ℓ = 93°. III. Multi-wavelength emission from SNR 3C 434.1

    NASA Astrophysics Data System (ADS)

    Foster, T.

    2005-10-01

    New Canadian Galactic Plane Survey radio continuum, ROSAT X-ray, and optical line observations of supernova remnant (SNR) 3C 434.1 (G94.0+1.0) are presented. A radio spectrum of index α=0.4 (where S∝ ν -α ) confirms this SNR's emission signature as predominantly synchrotron, and suggests the SNR is in the Sedov expansion phase. The morphology of the remnant is compared in X-ray, optical, and radio continuum, and the brightest emission in all three wavelength regimes is from the eastern hemisphere of 3C 434.1, which marks where the SNR shock is interacting with the inside wall of its stellar wind bubble (SWB) home. The system is determined to be 4.5 kpc distant, residing in the Perseus Arm Spiral shock. From a deep Hα mosaic of the region, λ 656 nm Hα line emission is observed that correlates well with radio synchrotron emission and anticorrelates with X-ray emission from the SNR. The origin of this optical emission is likely dense (ne=40 cm-3) cooling H II from the wall of the SWB, where the SNR shock has penetrated and become radiative (vs˜ 100 km s-1). The X-ray spectrum of this SNR between 0.5 and 2.4 keV is well modelled by a single-temperature thermal plasma (Te=4.5×106 K, ne=0.2 cm-3). The magnetic field of the bright radio synchrotron emission region is found (under the assumption of near equipartition) to be B˜ 15 μ G, a factor of 3 compression of the ambient ISM field (5 μ G). The westward extension of 3C 434.1 is the result of ongoing free expansion of the shock into the lower density interior of the SWB. I use multiwavelength observations to arrive at a unique solution for an interaction model of 3C 434.1 with the SWB, from which the age (t=25 000 yr) and mass ejected in the explosion (Mej=15.5 M⊙ ) are determined. I also find an initial blast-wave velocity of 1350 km s-1, typical of type 1b SNe.

  11. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  12. Classroom Interaction and Language Output

    ERIC Educational Resources Information Center

    Wang, Qiaoying; Castro, Carolyn D.

    2010-01-01

    This study investigates the effects of classroom interactions between a) students and students and b) students and teachers on the learning of English passivization by L1 Chinese adult learners of English as a foreign language during the language input and output treatments. In phase 1, both groups were asked to read and underline the input…

  13. SNR and Standard Deviation of cGNSS-R and iGNSS-R Scatterometric Measurements.

    PubMed

    Alonso-Arroyo, Alberto; Querol, Jorge; Lopez-Martinez, Carlos; Zavorotny, Valery U; Park, Hyuk; Pascual, Daniel; Onrubia, Raul; Camps, Adriano

    2017-01-19

    This work addresses the accuracy of the Global Navigation Satellite Systems (GNSS)-Reflectometry (GNSS-R) scatterometric measurements considering the presence of both coherent and incoherent scattered components, for both conventional GNSS-R (cGNSS-R) and interferometric GNSS-R (iGNSS-R) techniques. The coherent component is present for some type of surfaces, and it has been neglected until now because it vanishes for the sea surface scattering case. Taking into account the presence of both scattering components, the estimated Signal-to-Noise Ratio (SNR) for both techniques is computed based on the detectability criterion, as it is done in conventional GNSS applications. The non-coherent averaging operation is considered from a general point of view, taking into account that thermal noise contributions can be reduced by an extra factor of 0.88 dB when using partially overlapped or partially correlated samples. After the SNRs are derived, the received waveform's peak variability is computed, which determines the system's capability to measure geophysical parameters. This theoretical derivations are applied to the United Kingdom (UK) TechDemoSat-1 (UK TDS-1) and to the future GNSS REflectometry, Radio Occultation and Scatterometry on board the International Space Station (ISS) (GEROS-ISS) scenarios, in order to estimate the expected scatterometric performance of both missions.

  14. SNR and Standard Deviation of cGNSS-R and iGNSS-R Scatterometric Measurements

    PubMed Central

    Alonso-Arroyo, Alberto; Querol, Jorge; Lopez-Martinez, Carlos; Zavorotny, Valery U.; Park, Hyuk; Pascual, Daniel; Onrubia, Raul; Camps, Adriano

    2017-01-01

    This work addresses the accuracy of the Global Navigation Satellite Systems (GNSS)-Reflectometry (GNSS-R) scatterometric measurements considering the presence of both coherent and incoherent scattered components, for both conventional GNSS-R (cGNSS-R) and interferometric GNSS-R (iGNSS-R) techniques. The coherent component is present for some type of surfaces, and it has been neglected until now because it vanishes for the sea surface scattering case. Taking into account the presence of both scattering components, the estimated Signal-to-Noise Ratio (SNR) for both techniques is computed based on the detectability criterion, as it is done in conventional GNSS applications. The non-coherent averaging operation is considered from a general point of view, taking into account that thermal noise contributions can be reduced by an extra factor of 0.88 dB when using partially overlapped or partially correlated samples. After the SNRs are derived, the received waveform’s peak variability is computed, which determines the system’s capability to measure geophysical parameters. This theoretical derivations are applied to the United Kingdom (UK) TechDemoSat-1 (UK TDS-1) and to the future GNSS REflectometry, Radio Occultation and Scatterometry on board the International Space Station (ISS) (GEROS-ISS) scenarios, in order to estimate the expected scatterometric performance of both missions. PMID:28106825

  15. The First Fermi-LAT SNR Catalog: GeV Characteristics and Cosmic Ray Implications

    NASA Astrophysics Data System (ADS)

    Brandt, T. J.; Acero, F.; de Palma, F.; Hewitt, J.; Renaud, M.; Fermi-LAT Collaboration

    2015-08-01

    Galactic cosmic rays (CR) sources, classically proposed to be Supernova Remnants (SNRs), must meet the energetic particle content required by direct measurements of high energy CRs. Indirect gamma-ray measurements of SNRs with the Fermi Large Area Telescope (LAT) have now shown directly that at least three SNRs accelerate protons. With the first Fermi LAT SNR Catalog, we have systematically characterized the GeV gamma-rays emitted by 279 SNRs known primarily from radio surveys. We present these sources in a multiwavelength context, including studies of correlations between GeV and radio size, flux, and index, TeV index, and age and environment tracers, in order to better understand effects of evolution and environment on the GeV emission. We show that previously sufficient models of SNRs' GeV emission no longer adequately describe the data. To address the question of CR origins, we also examine the SNRs' maximal CR contribution assuming the GeV emission arises solely from proton interactions. Improved breadth and quality of multiwavelength data, including distances and local densities, and more, higher resolution gamma-ray data with correspondingly improved Galactic diffuse models will strengthen this constraint.

  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. The Monogem Ring: A Nearby SNR Similar to the Local Bubble ?

    NASA Astrophysics Data System (ADS)

    Plucinsky, P. P.

    2009-08-01

    The ``Monogem Ring'' is a large (D~25.0°), old (t~1.0×105 yr) supernova remnant (SNR) located above the Galactic plane close to the anti-center direction. The Monogem Ring (MR) has a very soft X-ray spectrum and is one of the most prominent features in the ROSAT All-Sky Survey R1+R2 Band (100-284 eV) map. The MR has been associated with the pulsar PSR 0656+14, which has a well-constrained distance from parallax measurements. Adopting a distance of 300 pc, we have modeled the MR as the remnant of a single SNe with an explosion energy of Eo = 0.2×1051 ergs, an initial ambient density of 5.2×10-3 cm-3, and an age of 8.6×104 yr. Comparison to multiple-SNe models of the Local Bubble indicate that the MR is a younger, less energetic explosion which went off in a lower density medium. We also present the first Suzaku spectrum of the MR ring which is consistent with a low-temperature (kT = 0.20 keV) plasma close to ionization equilibrium with a sub-solar O abundance.

  18. 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.

  19. GPS Diffractive Reflectometry and Further Developments in SNR- and Phase-based GPS Multipath Reflectometry

    NASA Astrophysics Data System (ADS)

    Geremia-Nievinski, F.; Ferreira e Silva, M.; Boniface, K.; Galera Monico, J. F.

    2015-12-01

    The validation of remote sensing environmental estimates requires knowledge of their spatial extent and resolution. Here we consider coherent radio reflections routinely observed in ground-based GPS reflectometry. Their footprint is often conceptualized in terms of the specular point (SP) and the first Fresnel zone (FFZ). Such infinitesimal point and finite zone can be generalized into a spatially continuous sensitivity kernel (SK). The SK represents a diffraction pattern, as the importance of each surface portion depends on its power and phase scattering. We measured the SK of a GPS radio reflection under bi-path reception conditions. The SK exhibited oscillations along the plane of incidence. The envelope of oscillations peaked near the SP and persisted in its decay well beyond the FFZ. Within the FFZ, sensitivity was skewed towards the antenna. This experiment suggests the feasibility of overcoming the diffraction limit and resolving features smaller than the FFZ via GPS diffractive reflectometry. We also report more recent developments in SNR- and carrier-phase-based GPS Multipath Reflectometry.

  20. Uncued Low SNR Detection with Likelihood from Image Multi Bernoulli Filter

    NASA Astrophysics Data System (ADS)

    Murphy, T.; Holzinger, M.

    2016-09-01

    Both SSA and SDA necessitate uncued, partially informed detection and orbit determination efforts for small space objects which often produce only low strength electro-optical signatures. General frame to frame detection and tracking of objects includes methods such as moving target indicator, multiple hypothesis testing, direct track-before-detect methods, and random finite set based multiobject tracking. This paper will apply the multi-Bernoilli filter to low signal-to-noise ratio (SNR), uncued detection of space objects for space domain awareness applications. The primary novel innovation in this paper is a detailed analysis of the existing state-of-the-art likelihood functions and a likelihood function, based on a binary hypothesis, previously proposed by the authors. The algorithm is tested on electro-optical imagery obtained from a variety of sensors at Georgia Tech, including the GT-SORT 0.5m Raven-class telescope, and a twenty degree field of view high frame rate CMOS sensor. In particular, a data set of an extended pass of the Hitomi Astro-H satellite approximately 3 days after loss of communication and potential break up is examined.

  1. New VLA observations of the SNR Puppis A: the radio properties and the correlation with the X-ray emission

    NASA Astrophysics Data System (ADS)

    Castelletti, G.; Dubner, G.; Golap, K.; Goss, W. M.

    2006-11-01

    Context: .High-resolution, high-sensitivity multifrequency radio images of supernova remnants (SNRs) are essential in advancing the understanding of both the global SNR dynamics and particle acceleration mechanisms. Aims: .In this paper we report on a new study of the SNR Puppis A based on VLA observations at 1425 MHz; the improvement represents a factor of two in angular resolution and almost ten times in sensitivity compared to the best previous image of Puppis A. This new image is used to compare with re-processed 327 MHz data and ROSAT and Chandra images to investigate morphological and spectral characteristics. Methods: . The observations were carried out with the VLA in the DnC and CnB configurations in 2004. After combining with single-dish data from Parkes, an angular resolution of 34'' × 16'' and an rms noise of 0.5 mJy beam-1, were achieved. Archival VLA data at 327 MHz were also processed. The spectral index distribution was then determined by a direct comparison of the homogenized data at both 327 and 1425 MHz. In addition, to identify different spectral components, tomographic spectral analysis was performed. Results: .The new 1425 MHz radio image reveals a highly structured border encircling a diffuse, featureless interior. In particular, the northern half of Puppis A displays a complex structure along the periphery, consisting of short arcs resembling "wave-like" features. These are oriented essentially perpendicular to the shock front on the NE side, but are tangential to the shock on the NW side. A remarkable correspondence between such "wave-like" features and spectral changes is observed. On the other hand, the brightest radio features (located to the E of the SNR and also detected in X-rays) have no counterpart in the spectral index distribution. Based on a uniform compilation of integrated flux densities between 19 and 8400 MHz, a global spectral index α = -0.52 ± 0.03 (S ∝ ν^α) has been determined. The new 1425 MHz image of Puppis A was

  2. Optimized filtering of regional and teleseismic seismograms: results of maximizing SNR measurements from the wavelet transform and filter banks

    SciTech Connect

    Leach, R.R.; Schultz, C.; Dowla, F.

    1997-07-15

    Development of a worldwide network to monitor seismic activity requires deployment of seismic sensors in areas which have not been well studied or may have from available recordings. Development and testing of detection and discrimination algorithms requires a robust representative set of calibrated seismic events for a given region. Utilizing events with poor signal-to-noise (SNR) can add significant numbers to usable data sets, but these events must first be adequately filtered. Source and path effects can make this a difficult task as filtering demands are highly varied as a function of distance, event magnitude, bearing, depth etc. For a given region, conventional methods of filter selection can be quite subjective and may require intensive analysis of many events. In addition, filter parameters are often overly generalized or contain complicated switching. We have developed a method to provide an optimized filter for any regional or teleseismically recorded event. Recorded seismic signals contain arrival energy which is localized in frequency and time. Localized temporal signals whose frequency content is different from the frequency content of the pre-arrival record are identified using rms power measurements. The method is based on the decomposition of a time series into a set of time series signals or scales. Each scale represents a time-frequency band with a constant Q. SNR is calculated for a pre-event noise window and for a window estimated to contain the arrival. Scales with high SNR are used to indicate the band pass limits for the optimized filter.The results offer a significant improvement in SNR particularly for low SNR events. Our method provides a straightforward, optimized filter which can be immediately applied to unknown regions as knowledge of the geophysical characteristics is not required. The filtered signals can be used to map the seismic frequency response of a region and may provide improvements in travel-time picking, bearing estimation

  3. The Master Hearing Aid

    PubMed Central

    Curran, James R.

    2013-01-01

    As early as the 1930s the term Master Hearing Aid (MHA) described a device used in the fitting of hearing aids. In their original form, the MHA was a desktop system that allowed for simulated or actual adjustment of hearing aid components that resulted in a changed hearing aid response. Over the years the MHA saw many embodiments and contributed to a number of rationales for the fitting of hearing aids. During these same years, the MHA was viewed by many as an inappropriate means of demonstrating hearing aids; the audio quality of the desktop systems was often superior to the hearing aids themselves. These opinions and the evolution of the MHA have molded the modern perception of hearing aids and the techniques used in the fitting of hearing aids. This article reports on a history of the MHA and its influence on the fitting of hearing aids. PMID:23686682

  4. Microgyroscope with closed loop output

    NASA Technical Reports Server (NTRS)

    Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)

    2002-01-01

    A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.

  5. UFO - The Universal FEYNRULES Output

    NASA Astrophysics Data System (ADS)

    Degrande, Céline; Duhr, Claude; Fuks, Benjamin; Grellscheid, David; Mattelaer, Olivier; Reiter, Thomas

    2012-06-01

    We present a new model format for automatized matrix-element generators, the so-called Universal FEYNRULES Output (UFO). The format is universal in the sense that it features compatibility with more than one single generator and is designed to be flexible, modular and agnostic of any assumption such as the number of particles or the color and Lorentz structures appearing in the interaction vertices. Unlike other model formats where text files need to be parsed, the information on the model is encoded into a PYTHON module that can easily be linked to other computer codes. We then describe an interface for the MATHEMATICA package FEYNRULES that allows for an automatic output of models in the UFO format.

  6. Research on output feedback control

    NASA Technical Reports Server (NTRS)

    Calise, A. J.; Kramer, F. S.

    1985-01-01

    In designing fixed order compensators, an output feedback formulation has been adopted by suitably augmenting the system description to include the compensator states. However, the minimization of the performance index over the range of possible compensator descriptions was impeded due to the nonuniqueness of the compensator transfer function. A controller canonical form of the compensator was chosen to reduce the number of free parameters to its minimal number in the optimization. In the MIMO case, the controller form requires a prespecified set of ascending controllability indices. This constraint on the compensator structure is rather innocuous in relation to the increase in convergence rate of the optimization. Moreover, the controller form is easily relatable to a unique controller transfer function description. This structure of the compensator does not require penalizing the compensator states for a nonzero or coupled solution, a problem that occurs when following a standard output feedback synthesis formulation.

  7. How to Get Hearing Aids

    MedlinePlus

    ... Consumer Products Hearing Aids How to get Hearing Aids Share Tweet Linkedin Pin it More sharing options ... my hearing aids? How do I get hearing aids? Before getting a hearing aid, you should consider ...

  8. Vocal output in preterm infants.

    PubMed

    Beckwith, L; Sigman, M; Cohen, S E; Parmelee, A H

    1977-11-01

    Data on vocal output of 51 preterm infants and 16 term infants were obtained during naturalistic home observations at 1, 3, and 8 months; during the administration of a preference-for-novelty paradigm in the laboratory at 8 months; and by the administration of the Gesell Developmental Schedules at 9 months. Preterm and term infant groups were found to show both similarities and differences: both groups vocalized a similar amount in the preference-for-novelty situation; both groups earned similar scores on the language subtest of the Gesell; both groups increased the percentage of awake time they spent in nondistress vocalization from 1 to 8 months. Term infants showed an earlier increase than did preterm infants: term infants significantly increased during the 1-3 month period, whereas preterm infants only increased significantly during the 3-8 month period. The developmental differences suggest a link between vocal output and perinatal conditions in that caregiver behavior was not found to be different among groups. Within the preterm groups, some relationships were found between vocal output and later test performance: infants who vocalized more during mutual gazing with the mother earned significantly higher scores on the language subtest of the Gesell.

  9. 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

  10. 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

  11. The Effects of Speech Output Technology on Skill Acquisition in Children with Autism Spectrum Disorder: A Preliminary Investigation

    ERIC Educational Resources Information Center

    Torres-Viso, Mariana Siku

    2015-01-01

    Previous research on the use of voice output communication aids (VOCAs) has found a number of positive effects on the behavior of both the VOCA user and their communicative partners. Among these outcomes, studies have found that incorporating speech output into language learning tasks may result in faster and more efficient learning for adults…

  12. New high resolution VLA mosaic at 1.4 GHz of the SNR Puppis A

    NASA Astrophysics Data System (ADS)

    Castelletti, G.; Dubner, G. M.; Golap, K.; Goss, W. M.

    2006-06-01

    We present new observations at 1.4 GHz of the supernova remnant (SNR) Puppis A made with the VLA in the hybrid DnC and CnB configurations (in 2003 and 2004, respectively). We observed this extended remnant (about 55' diameter) applying a mosaicking technique to combine 39 different pointings. The data were reduced using the AIPS++ software package. The multiscale clean method was used to deconvolve the image. The interferometric image was combined with single dish data extracted from the Parkes Southern Galactic Plane Survey (McClure-Griffiths et al. 2001, AJ, 551, 394) following a feathering technique which involves Fourier transforming of both the single dish and interferometric data onto identical grids. The new image produced by uniformly weighted visibility data, has a final angular resolution of 34 arcsec × 16 arcsec and an rms noise level of 0.5 mJy beam^{-1}; the improvement represents a factor of two in angular resolution and almost ten times in sensitivity compared to the best previous image of Puppis A at 1515 MHz (Dubner et al. 1991, AJ, 101, 1466; HPBW 77 arcsec × 43arcsec, rms noise 3 mJy beam^{-1}). For the first time a highly structured border encircling a diffuse, almost featureless interior was revealed in Puppis A. In particular the northern half of Puppis A displays a wealth of structure along the periphery consisting of short arcs that appear to be oriented rather perpendicular to the shock front on the northeast quadrant, but tangential to it on the northweast side.

  13. 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.

  14. SNR enhancement of highly-accelerated real-time cardiac MRI acquisitions based on non-local means algorithm.

    PubMed

    Naegel, Benoît; Cernicanu, Alexandru; Hyacinthe, Jean-Noël; Tognolini, Maurizio; Vallée, Jean-Paul

    2009-08-01

    Real-time cardiac MRI appears as a promising technique to evaluate the mechanical function of the heart. However, ultra-fast MRI acquisitions come with an important signal-to-noise ratio (SNR) penalty, which drastically reduces the image quality. Hence, a real-time denoising approach would be desirable for SNR amelioration. In the clinical context of cardiac dysfunction assessment, long acquisitions are required and for most patients the acquisition takes place with free breathing. Hence, it is necessary to compensate respiratory motion in real-time. In this article, a real-time and interactive method for sequential registration and denoising of real-time MR cardiac images is presented. The method has been experimented on 60 fast MRI acquisitions in five healthy volunteers and five patients. These experiments assessed the feasibility of the method in a real-time context.

  15. Cortical Auditory Evoked Potentials in (Un)aided Normal-Hearing and Hearing-Impaired Adults

    PubMed Central

    Van Dun, Bram; Kania, Anna; Dillon, Harvey

    2016-01-01

    Cortical auditory evoked potentials (CAEPs) are influenced by the characteristics of the stimulus, including level and hearing aid gain. Previous studies have measured CAEPs aided and unaided in individuals with normal hearing. There is a significant difference between providing amplification to a person with normal hearing and a person with hearing loss. This study investigated this difference and the effects of stimulus signal-to-noise ratio (SNR) and audibility on the CAEP amplitude in a population with hearing loss. Twelve normal-hearing participants and 12 participants with a hearing loss participated in this study. Three speech sounds—/m/, /g/, and /t/—were presented in the free field. Unaided stimuli were presented at 55, 65, and 75 dB sound pressure level (SPL) and aided stimuli at 55 dB SPL with three different gains in steps of 10 dB. CAEPs were recorded and their amplitudes analyzed. Stimulus SNRs and audibility were determined. No significant effect of stimulus level or hearing aid gain was found in normal hearers. Conversely, a significant effect was found in hearing-impaired individuals. Audibility of the signal, which in some cases is determined by the signal level relative to threshold and in other cases by the SNR, is the dominant factor explaining changes in CAEP amplitude. CAEPs can potentially be used to assess the effects of hearing aid gain in hearing-impaired users. PMID:27587919

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Automatic event detection in low SNR microseismic signals based on multi-scale permutation entropy and a support vector machine

    NASA Astrophysics Data System (ADS)

    Jia, Rui-Sheng; Sun, Hong-Mei; Peng, Yan-Jun; Liang, Yong-Quan; Lu, Xin-Ming

    2016-12-01

    Microseismic monitoring is an effective means for providing early warning of rock or coal dynamical disasters, and its first step is microseismic event detection, although low SNR microseismic signals often cannot effectively be detected by routine methods. To solve this problem, this paper presents permutation entropy and a support vector machine to detect low SNR microseismic events. First, an extraction method of signal features based on multi-scale permutation entropy is proposed by studying the influence of the scale factor on the signal permutation entropy. Second, the detection model of low SNR microseismic events based on the least squares support vector machine is built by performing a multi-scale permutation entropy calculation for the collected vibration signals, constructing a feature vector set of signals. Finally, a comparative analysis of the microseismic events and noise signals in the experiment proves that the different characteristics of the two can be fully expressed by using multi-scale permutation entropy. The detection model of microseismic events combined with the support vector machine, which has the features of high classification accuracy and fast real-time algorithms, can meet the requirements of online, real-time extractions of microseismic events.

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

    PubMed

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

    2016-10-06

    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 mm(2) 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.

  2. 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

  3. 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.

  4. Automated SVD filtering of time-frequency distribution for enhancing the SNR of microseismic/microquake events

    NASA Astrophysics Data System (ADS)

    Iqbal, Naveed; Zerguine, Azzedine; Kaka, SanLinn; Al-Shuhail, Abdullatif

    2016-12-01

    Recently, there has been a growing interest in continuous passive recording of passive microseismic experiments during reservoir fluid-injection monitoring, hydraulic-fracture monitoring and fault-movement monitoring, to name a few. The ability to accurately detect and analyze microseismic events generated by these activities is valuable in monitoring them. However, microseismic events usually have very low signal-to-noise ratio (SNR), especially when monitoring sensors (receivers) are located at the surface where coherent and non-coherent noise sources are overwhelming. Therefore, enhancing the SNR of the microseismic event will improve the localization process over the reservoir. In this study, a new method of enhancing the microseismic event is presented which relies on one trace per receiver record unlike other methods. The proposed method relies on a time-frequency representation and noise eliminating process which uses the singular-value decomposition (SVD) technique. Furthermore, the SVD is applied on the matrix representing the time-frequency decomposition of a trace. More importantly, an automated SVD filtering is proposed, so the SVD filtering becomes observation-driven instead of user-defined. Finally, it is shown that the proposed technique gives promising results with very low SNR, making it suitable to locate passive microseismic events even if the sensors are located on the surface.

  5. The X-space formulation of the magnetic particle imaging process: 1-D signal, resolution, bandwidth, SNR, SAR, and magnetostimulation.

    PubMed

    Goodwill, Patrick W; Conolly, Steven M

    2010-11-01

    The magnetic particle imaging (MPI) imaging process is a new method of medical imaging with great promise. In this paper we derive the 1-D MPI signal, resolution, bandwidth requirements, signal-to-noise ratio (SNR), specific absorption rate, and slew rate limitations. We conclude with experimental data measuring the point spread function for commercially available SPIO nanoparticles and a demonstration of the principles behind 1-D imaging using a static offset field. Despite arising from the nonlinear temporal response of a magnetic nanoparticle to a changing magnetic field, the imaging process is linear in the magnetization distribution and can be described as a convolution. Reconstruction in one dimension is exact and has a well-behaved quasi-Lorentzian point spread function.The spatial resolution improves cubically with increasing diameter of the SPIO domain, inverse to absolute temperature, linearly with saturation magnetization, and inversely with gradient. The band width requirements approach a megahertz for reasonable imaging parameters and millimeter scale resolutions, and the SNR increases with the scanning rate. The limit to SNR as we scale MPI to human sizes will be patient heating. SAR and magnetostimulation limits give us surprising relations between optimal scanning speeds and scanning frequency for different types of scanners.

  6. Nature of the Diffuse Source and Its Central Point-like Source in SNR 0509–67.5

    NASA Astrophysics Data System (ADS)

    Litke, Katrina C.; Chu, You-Hua; Holmes, Abigail; Santucci, Robert; Blindauer, Terrence; Gruendl, Robert A.; Li, Chuan-Jui; Pan, Kuo-Chuan; Ricker, Paul M.; Weisz, Daniel R.

    2017-03-01

    We examine a diffuse emission region near the center of SNR 0509‑67.5 to determine its nature. Within this diffuse region we observe a point-like source that is bright in the near-IR, but is not visible in the B and V bands. We consider an emission line observed at 6766 Å and the possibilities that it is Lyα, Hα, and [O ii] λ3727. We examine the spectral energy distribution (SED) of the source, comprised of Hubble Space Telescope B, V, I, J, and H bands in addition to Spitzer/IRAC 3.6, 4.5, 5.8, and 8 μm bands. The peak of the SED is consistent with a background galaxy at z ≈ 0.8 ± 0.2 and a possible Balmer jump places the galaxy at z ≈ 0.9 ± 0.3. These SED considerations support the emission line’s identification as [O ii] λ3727. We conclude that the diffuse source in SNR 0509‑67.5 is a background galaxy at z ≈ 0.82. Furthermore, we identify the point-like source superposed near the center of the galaxy as its central bulge. Finally, we find no evidence for a surviving companion star, indicating a double-degenerate origin for SNR 0509‑67.5.

  7. Effects of Postdetection on SNR in Optical Communications. How Various Types of Postdetection Affect the Performance of the Direct-Detection Optical Receiver.

    DTIC Science & Technology

    1981-06-11

    Afl-AIOG1 536 NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA F/G 17/2 EFFECTS OF POSTDETECTION ON SNR IN OPTICAL COMMUNICATIONS. HOW --ETC(U) JUN 81 R R...JAMES UNCLASSIFIED NOSC/TR-699 N EiEEEEEEEEE[N z (40 Technical Report 699 EFFECTS OF POSTDETECTION ON * SNR IN OPTICAL COMMUNICATIONS How various types...ERIOD COVERED EFFECTS OF POSTDETECTION ON SNR IN OPTICAL COMMUNI- Interim CATIONS . FY81 How various types of postdetection affect the performance of

  8. 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.

  9. Neurological Complications of AIDS

    MedlinePlus

    ... the neurological complications of AIDS. Some disorders require aggressive therapy while others are treated symptomatically. Medicines range ... certain bacterial infections, and penicillin to treat neurosyphilis. Aggressive antiretroviral therapy is used to treat AIDS dementia ...

  10. Unconsciousness - first aid

    MedlinePlus

    Loss of consciousness - first aid; Coma - first aid; Mental status change; Altered mental status ... person is unconscious and: Does not return to consciousness quickly (within a minute) Has fallen down or ...

  11. First Aid Tips

    MedlinePlus

    ... NEI for Kids > First Aid Tips All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

  12. Home Health Aides

    MedlinePlus

    ... do the following: Assist clients in their daily personal tasks, such as bathing or dressing Provide basic ... social networks and communities Home health aides, unlike personal care aides , typically work for certified home health ...

  13. AIDS and Athletes.

    ERIC Educational Resources Information Center

    Calabrese, Leonard H.; Kelley, Dennis

    1989-01-01

    This article discusses the onset and progression of AIDS, its importance as a public health issue, and reducing the risk of AIDS transmission among athletes and those who work with them, including team physicians and athletic trainers. (IAH)

  14. HIV/AIDS

    MedlinePlus

    ... at risk for serious infections and certain cancers. AIDS stands for acquired immunodeficiency syndrome. It is the final stage of infection with HIV. Not everyone with HIV develops AIDS. HIV most often spreads through unprotected sex with ...

  15. HIV/AIDS

    MedlinePlus

    ... yeast infection (thrush) Shingles (herpes zoster) Progression to AIDS If you receive no treatment for your HIV ... childbirth or breast-feeding. How does HIV become AIDS? HIV destroys CD4 cells — a specific type of ...

  16. HIV/AIDS Coinfection

    MedlinePlus

    ... Laotian Mongolian Spanish Turkish Vietnamese Hindi Subscribe HIV/AIDS Coinfection Approximately 10% of the HIV-infected population ... Control and Prevention website to learn about HIV/AIDS and Viral Hepatitis guidelines and resources. Home About ...

  17. Overload protection circuit for output driver

    DOEpatents

    Stewart, Roger G.

    1982-05-11

    A protection circuit for preventing excessive power dissipation in an output transistor whose conduction path is connected between a power terminal and an output terminal. The protection circuit includes means for sensing the application of a turn on signal to the output transistor and the voltage at the output terminal. When the turn on signal is maintained for a period of time greater than a given period without the voltage at the output terminal reaching a predetermined value, the protection circuit decreases the turn on signal to, and the current conduction through, the output transistor.

  18. AIDS in Rural California.

    ERIC Educational Resources Information Center

    Wooten, Donald B.

    1989-01-01

    Examines the increase in AIDS patients in rural California, which is greater than that in urban areas, including AIDS population projections through 1991. Describes differences between AIDS populations in rural and urban areas and relates these to state expenditure patterns and differential needs. (DHP)

  19. A Teaching Aids Exhibition.

    ERIC Educational Resources Information Center

    Mahanja, Salah

    1985-01-01

    Describes an exhibition for the benefit of teachers of English in Arab Primary Schools, which was prepared by third-year students at the Teachers College for Arab Teachers. The exhibition included games, songs, audiovisual aids, crossword puzzles, vocabulary, spelling booklets, preposition aids, and worksheet and lesson planning aids. (SED)

  20. Difficult Decisions: AIDS.

    ERIC Educational Resources Information Center

    Slesnick, Irwin L.

    1988-01-01

    Focuses on public education about the acquired immune deficiency syndrome (AIDS) epidemic. Discusses the problems of a second epidemic of fear and anxiety. Presents several questions for classroom discussion and analysis of the public fear of AIDS. Gives some statistics highlighting misinformation about AIDS. (CW)

  1. Stroke: First Aid

    MedlinePlus

    First aid Stroke: First aid Stroke: First aid By Mayo Clinic Staff A stroke occurs when there's bleeding into your brain or when normal blood flow to ... next several hours. Seek immediate medical assistance. A stroke is a true emergency. The sooner treatment is ...

  2. Creating Motivating Job Aids.

    ERIC Educational Resources Information Center

    Tilaro, Angie; Rossett, Allison

    1993-01-01

    Explains how to create job aids that employees will be motivated to use, based on a review of pertinent literature and interviews with professionals. Topics addressed include linking motivation with job aids; Keller's ARCS (Attention, Relevance, Confidence, Satisfaction) model of motivation; and design strategies for job aids based on Keller's…

  3. HIV and AIDS

    MedlinePlus

    ... A Week of Healthy Breakfasts Shyness HIV and AIDS KidsHealth > For Teens > HIV and AIDS Print A A A What's in this article? ... in human history. HIV causes a condition called acquired immunodeficiency syndrome — better known as AIDS . HIV destroys a type ...

  4. Designing State Aid Formulas

    ERIC Educational Resources Information Center

    Zhao, Bo; Bradbury, Katharine

    2009-01-01

    This paper designs a new equalization-aid formula based on fiscal gaps of local communities. When states are in transition to a new local aid formula, the issue of whether and how to hold existing aid harmless poses a challenge. The authors show that some previous studies and the formulas derived from them give differential weights to existing and…

  5. Space Derived Health Aids (AID, Heart Monitor)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    CPI's spinoff from miniaturized pace circuitry is the new heart-assist device, the AID implantable automatic pulse generator. AID pulse generator monitors the heart continuously, recognizes onset of fibrillation, then administers a corrective electrical shock. A mini- computer, a power source, and two electrodes which sense heart activity are included in the unit. An associated system was also developed. It includes an external recorder to be worn by AID patients and a physician's console to display the data stored by the recorder. System provides a record of fibrillation occurrences and the ensuing defibrillation.

  6. Mathematics and the Heart: Understanding Cardiac Output

    ERIC Educational Resources Information Center

    Champanerkar, Jyoti

    2013-01-01

    This paper illustrates a biological application of the concepts of relative change and area under a curve, from mathematics. We study two biological measures "relative change in cardiac output" and "cardiac output", which are predictors of heart blockages and other related ailments. Cardiac output refers to the quantity of…

  7. The Psycholinguistics of the Output Hypothesis.

    ERIC Educational Resources Information Center

    de Bot, Kees

    1996-01-01

    Elucidates the psycholinguistic mechanics of the "output hypothesis" and argues that output serves an important role in second language acquisition because it generates specific input the cognitive system needs to build up a coherent set of knowledge. The article hypothesizes that the locus of the effect of output is in the transition of…

  8. What Is HIV/AIDS?

    MedlinePlus

    ... Subscribe Translate Text Size Print What Is HIV/AIDS? Human Immunodeficiency Virus (HIV) HIV stands for human ... use the HIV Testing & Care Services Locator. GO Acquired Immunodeficiency Syndrome (AIDS) AIDS stands for acquired immunodeficiency syndrome. AIDS ...

  9. HIV, AIDS, and the Future

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV, AIDS, and the Future Past Issues / Summer 2009 Table ... and your loved ones from HIV/AIDS. The AIDS Memorial Quilt In 1987, a total of 1, ...

  10. Hearing Aid Assembly

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N. (Inventor)

    2002-01-01

    Progress in hearing aids has come a long way. Yet despite such progress hearing aids are not the perfect answer to many hearing problems. Some adult ears cannot accommodate tightly fitting hearing aids. Mouth movements such as chewing, talking, and athletic or other active endeavors also lead to loosely fitting ear molds. It is well accepted that loosely fitting hearing aids are the cause of feedback noise. Since feedback noise is the most common complaint of hearing aid wearers it has been the subject of various patents. Herein a hearing aid assembly is provided eliminating feedback noise. The assembly includes the combination of a hearing aid with a headset developed to constrict feedback noise.

  11. The Galactic Plane region near ℓ = 93°. II. A stellar wind bubble surrounding SNR 3C 434.1

    NASA Astrophysics Data System (ADS)

    Foster, T.; Routledge, D.; Kothes, R.

    2004-04-01

    New Canadian Galactic Plane Survey λ 21 cm H I line observations towards supernova remnant (SNR) 3C 434.1 (G94.0+1.0) are presented. We find a fragmented and thin-walled atomic hydrogen shell inside which the SNR is seen to be contained at v≃ -80 km s-1, which we report to be a highly evolved stellar wind bubble (SWB) associated with the remnant. A dark area in the midst of otherwise bright line emission is also seen near -71 km s-1. An absorption profile to the extragalactic continuum source 4C 51.45 (superimposed on the shell's north face) allows us to probe the shell's optical depth, kinetic temperature and expansion velocity. The material in the dark area has the same properties as material in the fragmented shell, suggesting that the dark area is actually the far-side ``cap'' of the shell seen absorbing emission from warm background gas, the first instance of H I Self Absorption (HISA) seen in such a structure. We show that the kinematic distance of 10 kpc derived from a flat Galactic rotation model is highly improbable, and that this bubble/SNR system is most likely resident in the Perseus Spiral Arm, lying 5.2 kpc distant. We model the SWB shell in three dimensions as a homologously expanding ellipsoid. Physical and dynamical characteristics of the bubble are determined, showing its advanced evolutionary state. Finally, from a photometric search for one or more stars associated with the SWB, we determine that three B0V stars and one O4V star currently inhabit this bubble, and that the progenitor of 3C 434.1 was at latest also an O4 type star.

  12. 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.

  13. 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.

  14. 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.

  15. Electrical vestibular stimuli to enhance vestibulo-motor output and improve subject comfort.

    PubMed

    Forbes, Patrick A; Dakin, Christopher J; Geers, Anoek M; Vlaar, Martijn P; Happee, Riender; Siegmund, Gunter P; Schouten, Alfred C; Blouin, Jean-Sébastien

    2014-01-01

    Electrical vestibular stimulation is often used to assess vestibulo-motor and postural responses in both clinical and research settings. Stochastic vestibular stimulation (SVS) is a recently established technique with many advantages over its square-wave counterpart; however, the evoked muscle responses remain relatively small. Although the vestibular-evoked responses can be enhanced by increasing the stimulus amplitude, subjects often perceive these higher intensity electrical stimuli as noxious or painful. Here, we developed multisine vestibular stimulation (MVS) signals that include precise frequency contributions to increase signal-to-noise ratios (SNR) of stimulus-evoked muscle and motor responses. Subjects were exposed to three different MVS stimuli to establish that: 1) MVS signals evoke equivalent vestibulo-motor responses compared to SVS while improving subject comfort and reducing experimentation time, 2) stimulus-evoked vestibulo-motor responses are reliably estimated as a linear system and 3) specific components of the cumulant density time domain vestibulo-motor responses can be targeted by controlling the frequency content of the input stimulus. Our results revealed that in comparison to SVS, MVS signals increased the SNR 3-6 times, reduced the minimum experimentation time by 85% and improved subjective measures of comfort by 20-80%. Vestibulo-motor responses measured using both EMG and force were not substantially affected by nonlinear distortions. In addition, by limiting the contribution of high frequencies within the MVS input stimulus, the magnitude of the medium latency time domain motor output response was increased by 58%. These results demonstrate that MVS stimuli can be designed to target and enhance vestibulo-motor output responses while simultaneously improving subject comfort, which should prove beneficial for both research and clinical applications.

  16. Model output: fact or artefact?

    NASA Astrophysics Data System (ADS)

    Melsen, Lieke

    2015-04-01

    As a third-year PhD-student, I relatively recently entered the wonderful world of scientific Hydrology. A science that has many pillars that directly impact society, for example with the prediction of hydrological extremes (both floods and drought), climate change, applications in agriculture, nature conservation, drinking water supply, etcetera. Despite its demonstrable societal relevance, hydrology is often seen as a science between two stools. Like Klemeš (1986) stated: "By their academic background, hydrologists are foresters, geographers, electrical engineers, geologists, system analysts, physicists, mathematicians, botanists, and most often civil engineers." Sometimes it seems that the engineering genes are still present in current hydrological sciences, and this results in pragmatic rather than scientific approaches for some of the current problems and challenges we have in hydrology. Here, I refer to the uncertainty in hydrological modelling that is often neglected. For over thirty years, uncertainty in hydrological models has been extensively discussed and studied. But it is not difficult to find peer-reviewed articles in which it is implicitly assumed that model simulations represent the truth rather than a conceptualization of reality. For instance in trend studies, where data is extrapolated 100 years ahead. Of course one can use different forcing datasets to estimate the uncertainty of the input data, but how to prevent that the output is not a model artefact, caused by the model structure? Or how about impact studies, e.g. of a dam impacting river flow. Measurements are often available for the period after dam construction, so models are used to simulate river flow before dam construction. Both are compared in order to qualify the effect of the dam. But on what basis can we tell that the model tells us the truth? Model validation is common nowadays, but validation only (comparing observations with model output) is not sufficient to assume that a

  17. Optical Waveguide Output Couplers Fabricated in Polymers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Johnson-Cole, Helen

    1998-01-01

    Waveguide output couplers fabricated in Norland Optical Adhesive (NOA) #81 and AMOCO Ultradel 9020D polyimide are investigated. The output couplers are implemented using periodic relief gratings on a planar waveguide. Design theory of the couplers is based on the perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. These couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. The results for the two different materials are compared.

  18. Collecting TIME-GCM Output Along TIMED Satellite Tracks

    NASA Astrophysics Data System (ADS)

    Hartsough, C. S.; Hagan, M. E.; Roble, R. G.

    2001-12-01

    The CEDAR/TIMED research effort focuses on increasing our understanding of the physical processes which affect and control the energetics and dynamics of the mesosphere and low er thermosphere. Use of upper-atmosphere models such as NCAR TIME-GCM can aid scientists in the interpretation of both satellite and ground-based observations. Our goals are (1) to make TIME-GCM model output readily available for researchers to use in their studies, and (2) to use the CEDAR/TIMED data to improve and upgrade the TIME-GCM model. We are preparing samples of TIME-GCM output to make available to the community via the Web. The data will be in netCDF format and accessible from the CEDAR database. Data will be sampled along the instrument observing tracks to facilitate direct comparisons with the TIMED instrument data. The data made available will approximately cover a 60-day period. The altitude range and fields to be made available will vary with each instrument, but will include neutral temperatures and winds, ion temperatures and drifts, and basic constituents, over approximately 50-300 km. Similar products will be made available for the CEDAR ground-based component of TIMED, including the NSF CEDAR Class 1 Facilities. We will present some sample data files and describe the Web site layout which researchers can use to access the TIME-GCM output as it becomes available.

  19. AIDS: acquired immunodeficiency syndrome.

    PubMed Central

    Gilmore, N. J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    1983-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of utmost importance. PMID:6342737

  20. AIDS: acquired immunodeficiency syndrome *

    PubMed Central

    Gilmore, N.J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    1992-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of the utmost importance. PMID:1544049

  1. Medical aid schemes respond to AIDS.

    PubMed

    Taylor, G

    1999-01-01

    The insurance and medical aid industries reacted strongly in the 1980s to alarmist predictions of the likely impact of HIV upon employee benefits. Actuaries and accountants moved quickly to contain the risk, and most medical aid trustees quickly implemented a total exclusion of HIV treatment from their benefits. For more than 1 decade, it was argued that HIV/AIDS is a self-inflicted illness, often categorized with other STDs. In response, healthcare providers simply bypassed insurance restrictions and compensation limits by masking patient diagnoses to reflect pneumonia or other ambiguous, yet fully reimbursable, illnesses. Now, common sense has finally prevailed as a few managed healthcare programs are stepping forward to break the impasse. The largest such program is Aid for AIDS, run by Pharmaceutical Benefit Management Ltd. for schemes within the Medscheme Group. The Group built an entirely new, secure unit off-site from their normal branches to guarantee the confidentiality of patients' records and diagnoses, while treatment guidelines have been issued to every practicing physician in the country.

  2. 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.

  3. 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

    SciTech Connect

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

    2015-07-20

    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 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 a 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), whichcan 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 ∼17,000-year-old composite SNR that expanded into a density gradient with an orientation perpendicular to the pulsar’s motion. We also show that the RS/PWN interaction scenario can reproduce the broadband spectrum of the PWN from radio to γ-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.

  4. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerléguer, L.

    2009-09-01

    PREVIMER is a pre-operational system aiming to provide a wide range of users, from private individuals to professionals, with short-term forecasts about the coastal environment along the French coastlines bordering the English Channel, the Atlantic Ocean, and the Mediterranean Sea. Observation data and digital modelling tools first provide 48-hour (probably 96-hour by summer 2009) forecasts of sea states, currents, sea water levels and temperatures. The follow-up of an increasing number of biological parameters will, in time, complete this overview of coastal environment. Working in partnership with the French Naval Hydrographic and Oceanographic Service (Service Hydrographique et Océanographique de la Marine, SHOM), the French National Weather Service (Météo-France), the French public science and technology research institute (Institut de Recherche pour le Développement, IRD), the European Institute of Marine Studies (Institut Universitaire Européen de la Mer, IUEM) and many others, IFREMER (the French public institute fo marine research) is supplying the technologies needed to ensure this pertinent information, available daily on Internet at http://www.previmer.org, and stored at the Operational Coastal Oceanographic Data Centre. Since 2006, PREVIMER publishes the results of demonstrators assigned to limited geographic areas and to specific applications. This system remains experimental. The following topics are covered : Hydrodynamic circulation, sea states, follow-up of passive tracers, conservative or non-conservative (specifically of microbiological origin), biogeochemical state, primary production. Lastly, PREVIMER provides researchers and R&D departments with modelling tools and access to the database, in which the observation data and the modelling results are stored, to undertake environmental studies on new sites. The communication will focus on meteorological inputs to and outputs from PREVIMER. It will draw the lessons from almost 3 years during

  5. Correlation between audio-visual enhancement of speech in different noise environments and SNR: a combined behavioral and electrophysiological study.

    PubMed

    Liu, B; Lin, Y; Gao, X; Dang, J

    2013-09-05

    In the present study, we investigated the multisensory gain as the difference of speech recognition accuracies between the audio-visual (AV) and auditory-only (A) conditions, and the multisensory gain as the difference between the event-related potentials (ERPs) evoked under the AV condition and the sum of the ERPs evoked under the A and visual-only (V) conditions in different noise environments. Videos of a female speaker articulating the Chinese monosyllable words accompanied with different levels of pink noise were used as the stimulus materials. The selected signal-to-noise ratios (SNRs) were -16, -12, -8, -4 and 0 dB. Under the A, V and AV conditions the accuracy of the speech recognition was measured and the ERPs evoked under different conditions were analyzed, respectively. The behavioral results showed that the maximum gain as the difference of speech recognition accuracies between the AV and A conditions was at the -12 dB SNR. The ERP results showed that the multisensory gain as the difference between the ERPs evoked under the AV condition and the sum of ERPs evoked under the A and V conditions at the -12 dB SNR was significantly higher than those at the other SNRs in the time window of 130-200 ms in the area from frontal to central region. The multisensory gains in audio-visual speech recognition at different SNRs were not completely accordant with the principle of inverse effectiveness, but confirmed to cross-modal stochastic resonance.

  6. Space-borne hyperspectral remote sensing imagery noise eliminating based on CFFT self-adapted by optimal SNR

    NASA Astrophysics Data System (ADS)

    Liu, Qingjie; Lin, Qizhong; Wang, Liming; Wang, Qinjun; Miao, Fengxian

    2010-09-01

    Space-borne hyperspectral remote sensing imagery, supplying both spatial and spectral information for quantitative remote sensing monitoring, is easily polluted by noises from atmosphere, terrain etc. Based on spectral continuum removing and recovering, traditional fast Fourier Transform (FFT) was extended to Continuum Fast Fourier Transform (CFFT) to separate noise from target information in frequency domain (FD). Thus, low-pass filter for reserving useful information was designed for eliminating noise, with its cut-off frequency selected self-adaptively by optimal signal-tonoise ratio (SNR). Hyperion hyperspectral imageries of Beijing and Xinjiang China were singled out for noise removing to validate the filtering ability of the Continuum Fast Fourier Transform self-adapted by Optimal Signal-noise Ratio(CFFTOSNR) method with qualitative description and quantificational indexs, including mean, variance, entropy, definition and SNR etc. Experiment result shows that CFFTOSNR does well in reducing the gauss white noises in spectral domain and stripe and band-subtracting noise in spatial domain respectively, while the quantificational indexs of filtered imagery are all improved, with entropy of post-processed image obviously increased by 5 db.

  7. 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.

  8. 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.

  9. PSR J1833-1034, the Very Young Pulsar in SNR G21.5-0.9

    NASA Astrophysics Data System (ADS)

    Camilo, Fernando; Gaensler, Bryan; Manchester, Dick; Ransom, Scott; Lorimer, Duncan Ross

    2007-04-01

    We have been timing the very young pulsar PSR J1833-1034, recently discovered near the center of the supernova remnant (SNR) G21.5-0.9 (Camilo et al. 2006). With 16 months of timing data in hand we have confirmed that the pulsar is coincident, to sub-arcsec precision, with the centrally-peaked X-ray source visible in Chandra data near the center of G21.5-0.9 and have therefore confirmed this pulsar-SNR association beyond any doubt. More unexpectedly, we have been able to measure this pulsar's braking index, n = 2.18, only the 6th such phase-coherent measurement done in over 1700 pulsars known. We now have a chance to measure the "second braking index" and place further constraints on the spin-down law obeyed by this pulsar. This has been done to date for only 2 pulsars. Finally, we wish to continue timing this pulsar because it will be one of the prime candidates for gamma-ray detection with the GLAST satellite to be launched in 2007, and in order to do so we must maintain its timing solution. For these reasons we request 24 hr for timing PSR J1833-1034 during the present semester.

  10. YOUNG REMNANTS OF TYPE Ia SUPERNOVAE AND THEIR PROGENITORS: A STUDY OF SNR G1.9+0.3

    SciTech Connect

    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.

  11. AIDS in South Africa.

    PubMed

    Ijsselmuiden, C; Evian, C; Matjilla, J; Steinberg, M; Schneider, H

    1993-01-01

    The National AIDS Convention in South Africa (NACOSA) in October 1992 was the first real attempt to address HIV/AIDS. In Soweto, government, the African National Congress, nongovernmental organizations, and organized industry and labor representatives worked for 2 days to develop a national plan of action, but it did not result in a united effort to fight AIDS. The highest HIV infection rates in South Africa are among the KwaZulu in Natal, yet the Inkatha Freedom Party did not attend NACOSA. This episode exemplifies the key obstacles for South Africa to prevent and control AIDS. Inequality of access to health care may explain why health workers did not diagnose the first AIDS case in blacks until 1985. Migrant labor, Bantu education, and uprooted communities affect the epidemiology of HIV infection. Further, political and social polarization between blacks and whites contributes to a mindset that AIDS is limited to the other race which only diminishes the personal and collective sense of susceptibility and the volition and aptitude to act. The Department of National Health and Population Development's voluntary register of anonymously reported cases of AIDS specifies 1517 cumulative AIDS cases (October 1992), but this number is low. Seroprevalence studies show between 400,000-450,000 HIV positive cases. Public hospitals cannot give AIDS patients AZT and DDI. Few communities provided community-based care. Not all hospitals honor confidentiality and patients' need for autonomy. Even though HIV testing is not mandatory, it is required sometimes, e.g., HIV testing of immigrants. AIDS Training, Information and Counselling Centers are in urban areas, but not in poor areas where the need is most acute. The government just recently developed in AIDS education package for schools, but too many people consider it improper, so it is not being used. The poor quality education provided blacks would make it useless anyhow. Lifting of the academic boycott will allow South African

  12. Prediction of electron beam output factors.

    PubMed

    Mills, M D; Hogstrom, K R; Almond, P R

    1982-01-01

    A method to predict square and rectangular field output factors from the measurement of selected fields of electron beams on the Therac 20 Saturne has been developed. A two parameter fit of the square field output factor data, based on the functional dependence as predicted by a pencil beam calculational model, has proven clinically acceptable. The pencil beam distributions are given by the Fermi-Eyges theory of multiple Coulomb scattering. For a rectangular field, the output factor can be calculated from the square root of the product of the two square field output factors wtih sides equal to those of the rectangular field. If however, there is a significant asymmetry between the X and Y collimator systems, then rectangular field output factors should be predicted from the product of the X and Y one-dimensional output factors. One-dimensional output factors are defined as output factors of rectangular fields where one side remains constant and equal to the side of the square reference field. Measured data indicate either of the two methods of determining rectangular field output factors to be clinically acceptable for the Therac 20, the use of one-dimensional output factors demonstrating greater accuracy. Data show agreement to within approximately 1.5% at electron energies of 6, 9, 13, and 17 MeV.

  13. AIDS and confidentiality.

    PubMed

    Kirkman, M B; Bell, S K

    1989-01-01

    AIDS has created many challenges for those who provide care for AIDS patients. One major challenge has been the request of many public officials for healthcare professionals to abandon the traditional view of confidentiality and to reveal AIDS patients' names. This ethical dilemma is explored and some ethical theories are presented as possible resolutions. The conclusion presented is that healthcare professionals must recognize that the power of the healthcare system over an AIDS patient is immense. Therefore, healthcare professionals must make a commitment to protect the patient's right to privacy by preventing any unauthorized disclosure at all costs.

  14. Computer Aided Modeling and Post Processing with NASTRAN Analysis

    NASA Technical Reports Server (NTRS)

    Boroughs, R. R.

    1984-01-01

    Computer aided engineering systems are invaluable tools in performing NASTRAN finite element analysis. These techniques are implemented in both the pre-processing and post-processing phases of the NASTRAN analysis. The finite element model development, or pre-processing phase, was automated with a computer aided modeling program called Supertabl, and the review and interpretation of the results of the NASTRAN analysis, or post-processing phase, was automated with a computer aided plotting program called Output Display. An intermediate program, Nasplot, which was developed in-house, has also helped to cut down on the model checkout time and reduce errors in the model. An interface has been established between the finite element computer aided engineering system and the Learjet computer aided design system whereby data can be transferred back and forth between the two. These systems have significantly improved productivity and the ability to perform NASTRAN analysis in response to product development requests.

  15. AIDS is your business.

    PubMed

    Rosen, Sydney; Simon, Jonathon; Vincent, Jeffrey R; MacLeod, William; Fox, Matthew; Thea, Donald M

    2003-02-01

    If your company operates in a developing country, AIDS is your business. While Africa has received the most attention, AIDS is also spreading swiftly in other parts of the world. Russia and Ukraine had the fastest-growing epidemics last year, and many experts believe China and India will suffer the next tidal wave of infection. Why should executives be concerned about AIDS? Because it is destroying the twin rationales of globalization strategy-cheap labor and fast-growing markets--in countries where people are heavily affected by the epidemic. Fortunately, investments in programs that prevent infection and provide treatment for employees who have HIV/AIDS are profitable for many businesses--that is, they lead to savings that outweigh the programs' costs. Due to the long latency period between HIV infection and the onset of AIDS symptoms, a company is not likely to see any of the costs of HIV/AIDS until five to ten years after an employee is infected. But executives can calculate the present value of epidemic-related costs by using the discount rate to weigh each cost according to its expected timing. That allows companies to think about expenses on HIV/AIDS prevention and treatment programs as investments rather than merely as costs. The authors found that the annual cost of AIDS to six corporations in South Africa and Botswana ranged from 0.4% to 5.9% of the wage bill. All six companies would have earned positive returns on their investments if they had provided employees with free treatment for HIV/AIDS in the form of highly active antiretroviral therapy (HAART), according to the mathematical model the authors used. The annual reduction in the AIDS "tax" would have been as much as 40.4%. The authors' conclusion? Fighting AIDS not only helps those infected; it also makes good business sense.

  16. Evaluation of Free Breathing Versus Breath Hold Diffusion Weighted Imaging in Terms Apparent Diffusion Coefficient (ADC) and Signal-to-Noise Ratio (SNR) Values for Solid Abdominal Organs

    PubMed Central

    Herek, Duygu; Karabulut, Nevzat; Kocyıgıt, Ali; Yagcı, Ahmet Baki

    2016-01-01

    Summary Background Our aim was to compare the apparent diffusion coefficient (ADC) values of normal abdominal parenchymal organs and signal-to-noise ratio (SNR) measurements in the same patients with breath hold (BH) and free breathing (FB) diffusion weighted imaging (DWI). Material/Methods Forty-eight patients underwent both BH and FB DWI. Spherical region of interest (ROI) was placed on the right hepatic lobe, spleen, pancreas, and renal cortices. ADC values were calculated for each organ on each sequence using an automated software. Image noise, defined as the standard deviation (SD) of the signal intensities in the most artifact-free area of the image background was measured by placing the largest possible ROI on either the left or the right side of the body outside the object in the recorded field of view. SNR was calculated using the formula: SNR=signal intensity (SI)(organ)/standard deviation (SD)(noise). Results There were no statistically significant differences in ADC values of the abdominal organs between BH and FB DWI sequences (p>0.05). There were statistically significant differences between SNR values of organs on BH and FB DWIs. SNRs were found to be better on FB DWI than BH DWI (p<0.001). Conclusions Free breathing DWI technique reduces image noise and increases SNR for abdominal examinations. Free breathing technique is therefore preferable to BH DWI in the evaluation of abdominal organs by DWI. PMID:27822326

  17. AIDS Fact Pack.

    ERIC Educational Resources Information Center

    Center for Population Options, Washington, DC.

    The three fact sheets presented in this document address issues surrounding adolescent sexuality and sexually transmitted diseases (STDs), especially the Acquired Immune Deficiency Syndrome (AIDS). The first fact sheet, "Young Women and AIDS: A Worldwide Perspective," suggests that since open discussions of adolescent sexuality have long been…

  18. Detecting Student Aid Fraud.

    ERIC Educational Resources Information Center

    Sheppard, Jeffrey

    1998-01-01

    Describes the varied kinds of student aid fraud found to be occurring within and outside colleges and universities, and examines implications for public policy on student aid programs. Discusses specific fraud cases and their outcomes, and makes suggestions for institutional action if student fraud is suspected. (MSE)

  19. Computer Aids to Translation.

    ERIC Educational Resources Information Center

    Krollmann, Friedrich

    1981-01-01

    Describes the structure and modes of operation of the Bundessprachenamt's (BSprA: Federal Office of Languages of the Federal Republic of Germany) terminology data bank as an aid to translation. Analyzes advantages and disadvantages of each user mode, and discusses probable developments in the immediate future of machine-aided translation. (MES)

  20. International Aid to Education

    ERIC Educational Resources Information Center

    Benavot, Aaron

    2010-01-01

    Recent evidence highlights several worrisome trends regarding aid pledges and disbursements, which have been exacerbated by the global financial crisis. First, while overall development assistance rose in 2008, after 2 years of decline, the share of all sector aid going to the education sector has remained virtually unchanged at about 12 percent…

  1. AIDS as Metaphor.

    ERIC Educational Resources Information Center

    McMillen, Liz

    1994-01-01

    Scholarly interest in Acquired Immune Deficiency Syndrome (AIDS) has spread throughout the humanities, attracting the attention of historians of medicine, political scientists, sociologists, public health scholars, and anthropologists. Most theorists hope their research will aid in policymaking or change understanding of the epidemic. (MSE)

  2. First Aid: Diaper Rash

    MedlinePlus

    ... Your 1- to 2-Year-Old First Aid: Diaper Rash KidsHealth > For Parents > First Aid: Diaper Rash A A A Diaper rash is a common skin condition in babies. ... rash is due to irritation caused by the diaper, but it can have other causes not related ...

  3. Hospital Nurse Aide. Revised.

    ERIC Educational Resources Information Center

    Iowa Univ., Iowa City. Coll. of Education.

    This report presents results of a project to revise the current 120-hour advanced nurse aide course to include all recommended minimum competencies. A three-page description of project objectives, activities, and outcomes is followed by a list of the competencies for the 75-hour nurse aide course for long-term care and for the 120-hour advanced…

  4. Preventing AIDS via Education.

    ERIC Educational Resources Information Center

    House, Reese M.; Walker, Catherine M.

    1993-01-01

    Compares the Acquired Immune Deficiency Syndrome (AIDS) epidemic to past epidemics, including social and political responses. Identifies populations at risk for human immunodeficiency virus (HIV) infection. Discusses current social and economic factors affecting AIDS education programs. Makes recommendations and identifies resources for starting…

  5. THE AIDS MYTH

    PubMed Central

    Poehlmann, Karl Horst

    1996-01-01

    AIDS is now said to threaten humanity as a modern-day scourge. However, there is a group of scientists which maintains that this scare is unwarranted. Some arguments in favour of the re-evaluation of the AIDS hypothesis are presented in this article. PMID:22556763

  6. AIDS: Children Too.

    ERIC Educational Resources Information Center

    Lejeune, Genevieve, Ed.

    1994-01-01

    This journal issue is devoted to the many problems faced by children with Acquired Immune Deficiency Syndrome (AIDS) who live in both developing and developed countries. Section 1 provides general information on the pandemic, defining AIDS and exploring the social aspects of the disease. It also addresses child health, child mortality, moral and…

  7. Aid, Development, and Education

    ERIC Educational Resources Information Center

    Klees, Steven J.

    2010-01-01

    The world faces pervasive poverty and inequality. Hundreds of billions of dollars in international aid have been given or loaned to developing countries though bilateral and multilateral mechanisms, at least, ostensibly, in order to do something about these problems. Has such aid helped? Debates around this question have been ongoing for decades,…

  8. BIBLIOGRAPHY OF TRAINING AIDS.

    ERIC Educational Resources Information Center

    MCKEONE, CHARLES J.

    THIS COMPILATION OF INSTRUCTIONAL AIDS FOR USE IN AIR-CONDITIONING AND REFRIGERATION TRAINING PROGRAMS CONTAINS LISTS OF VISUAL AND AUDIOVISUAL TRAINING AIDS AND GUEST LECTURERS AVAILABLE FROM MEMBER COMPANIES OF THE AIR-CONDITIONING AND REFRIGERATION INSTITUTE AS AN INDUSTRY SERVICE TO SCHOOL OFFICIALS INTERESTED IN CONDUCTING SUCH PROGRAMS. THE…

  9. AIDS and Chemical Dependency.

    ERIC Educational Resources Information Center

    Pohl, Melvin I.

    After defining HIV and the AIDS disease and outlining symptoms and means of infection, this fact sheet lists the ways alcohol and drugs are involved with the AIDS epidemic, noting that needle-sharing transmits the virus; that alcohol or mood-altering drugs like crack cocaine cause disinhibition, increase sex drive, encourage sex for drugs, and…

  10. First Aid: Falls

    MedlinePlus

    ... Your 1- to 2-Year-Old First Aid: Falls KidsHealth > For Parents > First Aid: Falls Print A A A en español Folleto de instructiones: Caídas (Falls) With all the running, climbing, and exploring kids ...

  11. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  12. Inertially Aided Robotics

    DTIC Science & Technology

    1989-12-31

    0031 dis~bti:,1 is uitsnjt( Deczmllcr 31: 1989 92-05530 2:.-: 3o : T >VE?-A ~ : Inertially Aided Robotics FINAL REPORT for Contract No. DAAHO1 -88-D-0057...1 2 Advantages of Inertially Aided Robotics ...86 iii List of Figures Figure 1 - Robot Manipulator having Joint Sensor Based Control ..................... 2

  13. Marketing Financial Aid

    ERIC Educational Resources Information Center

    Huddleston, Thomas, Jr.; Batty, Burt F.

    1978-01-01

    Student financial assistance services are becoming a major part of the institutional marketing plan as traditional college-age students decline in numbers and price competition among institutions increases. The effect of financial aid on enrollment and admissions processes is discussed along with the role of the financial aid officer. (Author/LBH)

  14. Participative AIDS Education Methods.

    ERIC Educational Resources Information Center

    Chambliss, Catherine; And Others

    Since assuring quality health care delivery to patients suffering from Acquired Immunodeficiency Syndrome (AIDS) and those who test positive for Human Immunodeficiency Virus (HIV) is a priority, development of effective staff training methods is imperative. This pilot study assessed the effect on staff attitudes of a participative AIDS/HIV staff…

  15. Innovative Teaching Aids.

    ERIC Educational Resources Information Center

    Christner, Chris

    1988-01-01

    Describes the DACUM (Developing A CurriculUM) process and how it is used at Universal Technical Institute to determine what types of training aids to produce. Indicates that examining the employment needs of industry and educational needs of students enhances programs and promotes development of innovative aids. (JOW)

  16. First Aid: Burns

    MedlinePlus

    ... Your 1- to 2-Year-Old First Aid: Burns KidsHealth > For Parents > First Aid: Burns A A A Scald burns from hot water and other liquids are the most common burns in early childhood. Because burns range from mild ...

  17. The New Merit Aid

    ERIC Educational Resources Information Center

    Dynarski, Susan

    2004-01-01

    Merit aid, a discount to college costs contingent upon academic performance, is nothing new. Colleges and private organizations have long rewarded high-achieving, college-bound high school students with scholarships. While merit aid has a long history in the private sector, it has not played a major role in the public sector. At the state level,…

  18. AIDS Epidemiological models

    NASA Astrophysics Data System (ADS)

    Rahmani, Fouad Lazhar

    2010-11-01

    The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

  19. AIDS in the pre-AIDS era.

    PubMed

    Huminer, D; Rosenfeld, J B; Pitlik, S D

    1987-01-01

    A search of the medical literature published since 1950 disclosed 19 cases of probable AIDS reported before the start of the current epidemic. These cases retrospectively met the Centers for Disease Control's surveillance definition of the syndrome and had a clinical course suggestive of AIDS. The reports originated from North America, Western Europe, Africa, and the Middle East. The mean age of patients was 37 years, and the ratio of male to female patients was 1.7:1. Sixteen patients had opportunistic infections(s) without Kaposi's sarcoma. The remainder had disseminated Kaposi's sarcoma. The commonest opportunistic infection was Pneumocystis carinii pneumonia. Two patients were reported to be homosexual. Three others had been living in Africa, and one patient was born in Haiti. In two instances concurrent or subsequent opportunistic infection occurred in family members. All patients died 1 month to 6 years after the initial manifestation of disease. In view of the historical data, unrecognized cases of AIDS appear to have occurred sporadically in the pre-AIDS era.

  20. AFB's Computerized Travel Aid: Two Years of Research and Development.

    ERIC Educational Resources Information Center

    Uslan, Mark M.; And Others

    1983-01-01

    Progress on the computerized travel aid, an electronic device, using elements of the Polaroid Sonar Camera and a microprocessor, for visually handicapped persons is reviewed, and research on the effectiveness of various models noted. Recommended modifications touch on aspects of mounting, beam shape, and audible outputs. (CL)

  1. Submarine Periscope Depth Course Selection Tactical Decision Aid

    DTIC Science & Technology

    1997-12-01

    Tactical Decision Aid, Simulations using PAGES Visual Basic Programming 64 16. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION OF 19...27 APPENDIX A. COMPOSITE OUTPUT DISPLAYS ..................................................................... 29 APPENDIX B. VISUAL BASIC SOURCE...41 APPENDIX D. VISUAL BASIC SOURCE CODE FOR SIMULATION ......................................... 43 APPENDIX E

  2. 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.

  3. Discovery of dominant and dormant genes from expression data using a novel generalization of SNR for multi-class problems

    PubMed Central

    Tsai, Yu-Shuen; Lin, Chin-Teng; Tseng, George C; Chung, I-Fang; Pal, Nikhil Ranjan

    2008-01-01

    Background The Signal-to-Noise-Ratio (SNR) is often used for identification of biomarkers for two-class problems and no formal and useful generalization of SNR is available for multiclass problems. We propose innovative generalizations of SNR for multiclass cancer discrimination through introduction of two indices, Gene Dominant Index and Gene Dormant Index (GDIs). These two indices lead to the concepts of dominant and dormant genes with biological significance. We use these indices to develop methodologies for discovery of dominant and dormant biomarkers with interesting biological significance. The dominancy and dormancy of the identified biomarkers and their excellent discriminating power are also demonstrated pictorially using the scatterplot of individual gene and 2-D Sammon's projection of the selected set of genes. Using information from the literature we have shown that the GDI based method can identify dominant and dormant genes that play significant roles in cancer biology. These biomarkers are also used to design diagnostic prediction systems. Results and discussion To evaluate the effectiveness of the GDIs, we have used four multiclass cancer data sets (Small Round Blue Cell Tumors, Leukemia, Central Nervous System Tumors, and Lung Cancer). For each data set we demonstrate that the new indices can find biologically meaningful genes that can act as biomarkers. We then use six machine learning tools, Nearest Neighbor Classifier (NNC), Nearest Mean Classifier (NMC), Support Vector Machine (SVM) classifier with linear kernel, and SVM classifier with Gaussian kernel, where both SVMs are used in conjunction with one-vs-all (OVA) and one-vs-one (OVO) strategies. We found GDIs to be very effective in identifying biomarkers with strong class specific signatures. With all six tools and for all data sets we could achieve better or comparable prediction accuracies usually with fewer marker genes than results reported in the literature using the same computational

  4. 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

  5. Electroacoustic Evaluation of Frequency-Modulated Receivers Interfaced with Personal Hearing Aids

    ERIC Educational Resources Information Center

    Schafer, Erin C.; Thibodeau, Linda M.; Whalen, Holly S.; Overson, Gary J.

    2007-01-01

    Purpose: The purpose of this study was to compare the electroacoustic outputs of frequency-modulated (FM) systems coupled to hearing aids. Method: Electroacoustic performance of FM systems coupled to hearing aids was determined for 3 FM receivers: body-worn with neck loop, ear-level nonprogrammable, and ear-level programmable. Systems were…

  6. Acoustical and Perceptual Comparison of Noise Reduction and Compression in Hearing Aids

    ERIC Educational Resources Information Center

    Brons, Inge; Houben, Rolph; Dreschler, Wouter A.

    2015-01-01

    Purpose: Noise reduction and dynamic-range compression are generally applied together in hearing aids but may have opposite effects on amplification. This study evaluated the acoustical and perceptual effects of separate and combined processing of noise reduction and compression. Design: Recordings of the output of 4 hearing aids for speech in…

  7. DIST/AVC Out-Put Definition.

    ERIC Educational Resources Information Center

    Wilkinson, Gene L.

    The first stage of development of a management information system for DIST/AVC (Division of Instructional Technology/Audio-Visual Center) is the definition of out-put units. Some constraints on the definition of output units are: 1) they should reflect goals of the organization, 2) they should reflect organizational structure and procedures, and…

  8. Power output measurement during treadmill cycling.

    PubMed

    Coleman, D A; Wiles, J D; Davison, R C R; Smith, M F; Swaine, I L

    2007-06-01

    The study aim was to consider the use of a motorised treadmill as a cycling ergometry system by assessing predicted and recorded power output values during treadmill cycling. Fourteen male cyclists completed repeated cycling trials on a motorised treadmill whilst riding their own bicycle fitted with a mobile ergometer. The speed, gradient and loading via an external pulley system were recorded during 20-s constant speed trials and used to estimate power output with an assumption about the contribution of rolling resistance. These values were then compared with mobile ergometer measurements. To assess the reliability of measured power output values, four repeated trials were conducted on each cyclist. During level cycling, the recorded power output was 257.2 +/- 99.3 W compared to the predicted power output of 258.2 +/- 99.9 W (p > 0.05). For graded cycling, there was no significant difference between measured and predicted power output, 268.8 +/- 109.8 W vs. 270.1 +/- 111.7 W, p > 0.05, SEE 1.2 %. The coefficient of variation for mobile ergometer power output measurements during repeated trials ranged from 1.5 % (95 % CI 1.2 - 2.0 %) to 1.8 % (95 % CI 1.5 - 2.4 %). These results indicate that treadmill cycling can be used as an ergometry system to assess power output in cyclists with acceptable accuracy.

  9. High Power Amplifier Harmonic Output Level Measurement

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.; Khan, A. R.

    1995-01-01

    A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

  10. Computer Output Microfilm and Library Catalogs.

    ERIC Educational Resources Information Center

    Meyer, Richard W.

    Early computers dealt with mathematical and scientific problems requiring very little input and not much output, therefore high speed printing devices were not required. Today with increased variety of use, high speed printing is necessary and Computer Output Microfilm (COM) devices have been created to meet this need. This indirect process can…

  11. Reinvestigating the Noticing Function of Output

    ERIC Educational Resources Information Center

    Uggen, Maren S.

    2012-01-01

    A conceptual replication of Izumi and Bigelow's research, this study used multiple measures to investigate second language (L2) learners' processes in output-input-output sequences. Specifically, it examined whether producing the target language impacts learners' attention to L2 structures in subsequent input. Thirty learners of English as a…

  12. Seasonal variations of cardiac output in rats.

    PubMed

    Back, G; Strubelt, O

    1975-11-15

    Cardiac output of rats shows seasonal variations with low values in spring and summer and high ones in autumn and winter. The stroke volume was much more implicated in these changes than the heart rate. The seasonal changes of cardiac output are probably due to changes of thyroid function.

  13. Silicon carbide diode for increased light output

    NASA Technical Reports Server (NTRS)

    Griffiths, L. B.; Mlavsky, A. I.

    1969-01-01

    Transition metals improve the overall light output and the output in particular regions of the electroluminescent of a silicon carbide semiconductor device. These metals /impurities/ introduce levels that can be pumped electrically and affect the efficiency of the recombination process involved in emission of radiation.

  14. 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.

  15. New Hubble Space Telescope Observations of High-Velocity Ly(alpha) and H(alpha) in SNR 1987A

    NASA Technical Reports Server (NTRS)

    Michael, Eli; McCray, Richard; Pun, C. S. J.; Borkowski, Kazimierz; Garnavich, Peter; Challis, Peter; Kirshner, Robert P.; Chevalier, Roger; Filippenko, Alexei V.; Fransson, Claes; Panagia, Nino; Phillips, Mark; Schmidt, Brian; Suntzef, Nicholas

    1998-01-01

    We describe and model high-velocity (approximately 15,000 km S(exp -1)) Ly Alpha and H Alpha emission from the supernova remnant SNR 1987A seen in 1997 September and October with the Space Telescope Imaging Spectrograph. Part of this emission comes from a reverse shock located at approximately 75% of the radius of the inner boundary ofthe innercircumstellar ring and confined within + or - 30 degrees of the equatorial plane. Departure from axisymmetry in the Ly Alpha and H Alpha emission correlates with that seen in nonthermal radio emission and reveals an asymmetry in the circumstellar gas distribution. We also see diffuse high-velocity Ly-Alpha emission from supernova debris inside the reverse shock that may be due to excitation by nonthermal particles accelerated by the shock.

  16. 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.

  17. Far-Flung Filaments of Fast Ejecta in the Oxygen-Rich SNR G292.0+1.8

    NASA Astrophysics Data System (ADS)

    Winkler, P. F.; Reith, C. N.; Long, K. S.

    2005-05-01

    New optical images of the young supernova remnant (SNR) G292.0+1.8, obtained from the 0.9-m telescope at CTIO, show a far more extensive network of filaments than previous data indicate. Images in [O III] show filaments distributed throughout much of the 8 arcmin diameter shell seen in X-ray and radio images. Many of the outer filaments have a radial, pencil-like morphology that is very suggestive of Rayleigh-Tayor fingers. Comparison of images from epochs 1986-2002 shows filamentary proper motions roughly in the direction of these fingers, consistent with expansion from a point near the central pulsar with a kinematic age of about 3000 yr. Simulations of core-collapse supernovae predict the development of such fingers, but they have never before been so clearly observed in a young SNR. In addition to the extensive [O III] filaments, we have detected three small complexes of filaments that show [S II] emission along with the oxygen lines. None of the fast filaments, with or without [S II], show any evidence for hydrogen; all must be composed of pure supernova ejecta. Limited spectra indicate differences of more than a factor of 5 in the relative strengths of S and O lines, which cannot be attributed to differences in excitation. The progenitor to G292.0+1.8 must have undergone at least some oxygen burning, the products of which have been mixed in variable amounts into at least a few filaments of ejecta. This research has been funded primarily by the National Science Foundation through grant AST-0307613.

  18. 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.

  19. 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.

  20. Optimization of PET activation studies based on the SNR measured in the 3-D Hoffman brain phantom.

    PubMed

    Li, H H; Votaw, J R

    1998-08-01

    This work investigates the noise properties of O-15 water PET images in an attempt to increase the sensitivity of activation studies. A method for computing the amount of noise within a region of interest (ROI) from the uncertainty in the raw data was implemented for three-dimensional (3-D) positron emission tomography (PET). The method was used to study the signal-to-noise ratio (SNR) of regions-of-interest (ROI's) inside a 3-D Hoffman brain phantom. Saturation occurs at an activity concentration of 2.2 mCi/l which corresponds to a 75-mCi O-15 water injection into a normal person of average weight. This establishes the upper limit for injections for human brain studies using 3-D PET on the Siemens ECAT 921 EXACT scanner. Data from human brain activation studies on four normal volunteers using two-dimensional (2-D) PET were analyzed. The biological variation was found to be 5% in 1-ml ROI's. The variance for a complete activation study was calculated, for a variety of protocols, by combining the Poisson noise propagated from the raw data in the phantom experiments with the biological variation. A protocol that is predicted to maximize the SNR in dual-condition activation experiments while remaining below the radiation safety limit is: ten scans with 45 mCi per injection. The data should not be corrected for random or scatter events since they do not help in the identification of activation sites while they do add noise to the image. Due to the lower noise level of 3-D PET, the threshold for detecting a true change in activity concentration is 10%-20% lower than 2-D PET. Because of this, a 3-D activation experiment using the Siemens 921 scanner requires fewer subjects for equal statistical power.

  1. Optimal Output Trajectory Redesign for Invertible Systems

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh

    1996-01-01

    Given a desired output trajectory, inversion-based techniques find input-state trajectories required to exactly track the output. These inversion-based techniques have been successfully applied to the endpoint tracking control of multi-joint flexible manipulators and to aircraft control. The specified output trajectory uniquely determines the required input and state trajectories that are found through inversion. These input-state trajectories exactly track the desired output; however, they might not meet acceptable performance requirements. For example, during slewing maneuvers of flexible structures, the structural deformations, which depend on the required state trajectories, may be unacceptably large. Further, the required inputs might cause actuator saturation during an exact tracking maneuver for example, in the flight control of conventional takeoff and landing aircraft. In such situations, a compromise is desired between the tracking requirement and other goals such as reduction of internal vibrations and prevention of actuator saturation; the desired output trajectory needs to be redesigned.

  2. HIV / AIDS and tourism.

    PubMed

    Forsythe, S

    1999-01-01

    Since it tends to be significantly affected by HIV/AIDS, the tourism sector is a likely target for HIV/AIDS interventions in many countries. The tourist industry is at particular risk from the pandemic because of the mobility of the work force, the presence of sex tourists, and the heavy reliance of many countries upon tourism revenues. Indeed, tourism is one of the largest and fastest growing industries in many countries. Some people have speculated that potential tourists' fear of AIDS could discourage them from visiting certain countries, while others have even suggested that tourism should be discouraged because the industry contributes to the spread of HIV/AIDS. When traveling, tourists often take risks that they would not take at home. They tend to drink more, use drugs more, and be generally more adventurous while on holiday. Such adventures often include taking sexual risks. When tourists have sex with prostitutes, hotel staff, and others in the local population, a bridge can be created for HIV to cross back and forth between the tourist's home country and the tourist destination. The author reviews selected studies on the relationship between HIV/AIDS and tourism. Overall, the existing literature offers no definitive evidence that AIDS has had any lasting impact upon the tourism industry anywhere in the world. Rather, promoting a healthy tourism industry and HIV/AIDS prevention are likely complementary in many ways.

  3. AIDS radio triggers.

    PubMed

    Elias, A M

    1991-07-01

    In April 1991, the Ethnic Communities' Council of NSW was granted funding under the Community AIDS Prevention and Education Program through the Department of Community Services and Health, to produce a series of 6x50 second AIDS radio triggers with a 10-second tag line for further information. The triggers are designed to disseminate culturally-sensitive information about HIV/AIDS in English, Italian, Greek, Spanish, Khmer, Turkish, Macedonian, Serbo-Croatian, Arabic, Cantonese, and Vietnamese, with the goal of increasing awareness and decreasing the degree of misinformation about HIV/AIDS among people of non-English-speaking backgrounds through radio and sound. The 6 triggers cover the denial that AIDS exists in the community, beliefs that words and feelings do not protect one from catching HIV, encouraging friends to be compassionate, compassion within the family, AIDS information for a young audience, and the provision of accurate and honest information on HIV/AIDS. The triggers are slated to be completed by the end of July 1991 and will be broadcast on all possible community, ethnic, and commercial radio networks across Australia. They will be available upon request in composite form with an information kit for use by health care professionals and community workers.

  4. Hearing AIDS and music.

    PubMed

    Chasin, Marshall; Russo, Frank A

    2004-01-01

    Historically, the primary concern for hearing aid design and fitting is optimization for speech inputs. However, increasingly other types of inputs are being investigated and this is certainly the case for music. Whether the hearing aid wearer is a musician or merely someone who likes to listen to music, the electronic and electro-acoustic parameters described can be optimized for music as well as for speech. That is, a hearing aid optimally set for music can be optimally set for speech, even though the converse is not necessarily true. Similarities and differences between speech and music as inputs to a hearing aid are described. Many of these lead to the specification of a set of optimal electro-acoustic characteristics. Parameters such as the peak input-limiting level, compression issues-both compression ratio and knee-points-and number of channels all can deleteriously affect music perception through hearing aids. In other cases, it is not clear how to set other parameters such as noise reduction and feedback control mechanisms. Regardless of the existence of a "music program,'' unless the various electro-acoustic parameters are available in a hearing aid, music fidelity will almost always be less than optimal. There are many unanswered questions and hypotheses in this area. Future research by engineers, researchers, clinicians, and musicians will aid in the clarification of these questions and their ultimate solutions.

  5. Solidarity and AIDS: introduction.

    PubMed

    Krieger, N

    1991-01-01

    Perhaps more than any other disease in recent history, AIDS has taught a cruel and crucial lesson: the constraints on our response to this epidemic are as deep as our denial, as entrenched as the inequities that permeate our society, as circumscribed as our knowledge, and as unlimited as our compassion and our commitment to human rights. Elaborating on these themes, the final three articles in this Special Section on AIDS consider three widely divergent yet intimately connected topics: AIDS in Cuba, AIDS in Brazil, and global AIDS prevention in the 1990s. Together, they caution that if we persist in treating AIDS as a problem only of "others," no country will be spared the social and economic devastation that promises to be the cost of our contempt and our folly. Solidarity is not an option; it is a necessity. Without conscious recognition of the worldwide relationship between health, human rights, and social inequalities, our attempts to abate the spread of AIDS--and to ease the suffering that follows in its wake--most surely will fall short of our goals. Finally, as we mourn our dead, we must take to heart the words of Mother Jones, and "fight like hell for living." This is the politics of survival.

  6. Hearing Aids and Music

    PubMed Central

    Chasin, Marshall; Russo, Frank A.

    2004-01-01

    Historically, the primary concern for hearing aid design and fitting is optimization for speech inputs. However, increasingly other types of inputs are being investigated and this is certainly the case for music. Whether the hearing aid wearer is a musician or merely someone who likes to listen to music, the electronic and electro-acoustic parameters described can be optimized for music as well as for speech. That is, a hearing aid optimally set for music can be optimally set for speech, even though the converse is not necessarily true. Similarities and differences between speech and music as inputs to a hearing aid are described. Many of these lead to the specification of a set of optimal electro-acoustic characteristics. Parameters such as the peak input-limiting level, compression issues—both compression ratio and knee-points—and number of channels all can deleteriously affect music perception through hearing aids. In other cases, it is not clear how to set other parameters such as noise reduction and feedback control mechanisms. Regardless of the existence of a “music program,” unless the various electro-acoustic parameters are available in a hearing aid, music fidelity will almost always be less than optimal. There are many unanswered questions and hypotheses in this area. Future research by engineers, researchers, clinicians, and musicians will aid in the clarification of these questions and their ultimate solutions. PMID:15497032

  7. Women and HIV/AIDS

    MedlinePlus

    ... AIDS email updates Enter email Submit HIV and AIDS The human immunodeficiency (IH-myoo-noh-di-FISH- ... health Pregnancy and HIV View more HIV and AIDS resources Related information Birth control methods Sexually transmitted ...

  8. HIV / AIDS: An Unequal Burden

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV / AIDS: An Unequal Burden Past Issues / Summer 2009 Table ... Victoria Cargill talks to students about HIV and AIDS at the opening of a National Library of ...

  9. HIV/AIDS and Alcohol

    MedlinePlus

    ... Psychiatric Disorders Other Substance Abuse HIV/AIDS HIV/AIDS Human immunodeficiency virus (HIV) targets the body’s immune ... and often leads to acquired immune deficiency syndrome (AIDS). Each year in the United States, between 55, ...

  10. Research Report: HIV/AIDS

    MedlinePlus

    ... Reports » HIV/AIDS » Letter from the Director HIV/AIDS Email Facebook Twitter Letter from the Director Human ... the virus that causes acquired immune deficiency syndrome (AIDS) — has been with us for three decades now. ...

  11. HIV/AIDS and Vaccines

    MedlinePlus

    ... NIAID). /* // ** // */ Prevention Research Vaccines Microbicides Related Topics on AIDS.gov Clinical Trials Immune System 101 HIV Vaccine ... Be the Generation Last revised: 12/09/2016 AIDS.gov HIV/AIDS Basics • Federal Resources • Using New ...

  12. Evaluation of pixel-wise geometric constraint-based phase-unwrapping method for low signal-to-noise-ratio (SNR) phase

    NASA Astrophysics Data System (ADS)

    An, Yatong; Liu, Ziping; Zhang, Song

    2016-12-01

    This paper evaluates the robustness of our recently proposed geometric constraint-based phase-unwrapping method to unwrap a low-signal-to-noise ratio (SNR) phase. Instead of capturing additional images for absolute phase unwrapping, the new phase-unwrapping algorithm uses geometric constraints of the digital fringe projection (DFP) system to create a virtual reference phase map to unwrap the phase pixel by pixel. Both simulation and experimental results demonstrate that this new phase-unwrapping method can even successfully unwrap low-SNR phase maps that bring difficulties for conventional multi-frequency phase-unwrapping methods.

  13. Political dimensions of AIDS.

    PubMed

    Blewett, N

    1988-01-01

    World political aspects and the example of Australia as a national political response to AIDS are presented. Global policy on AIDS is influenced by the fact that the AIDS epidemic is the 1st to be largely predictable, that long lag times occur between intervention and measurable events, and by the prompt, professional leadership of WHO, lead by Dr. J. Mann. WHO began a Global Programme on AIDS in 1987, modelled on the responses of Canada and Australia. A world summit of Ministers of Health was convened in January 1988. These moves generated a response qualified by openness, cooperation, hope and common sense. The AIDS epidemic calls for unprecedented involvement of politicians: they must coordinate medical knowledge with community action, deal with public fear, exert strong, rational leadership and avoid quick, appealing counterproductive responses. 3 clear directions must be taken to deal with the epidemic: 1) strong research and education campaigns; 2) close contact with political colleagues, interest groups and the community; 3) a national strategy which enjoins diverse interest groups, with courage, rationality and compassion. In Australia, the AIDS response began with the unwitting infection of 3 infants by blood transfusion. A public information campaign emphasizing a penetrating TV ad campaign was instituted in 1987. Policy discussions were held in all parliamentary bodies. The AIDS epidemic demands rapid, creative responses, a break from traditions in health bureaucracy, continual scrutiny of funding procedures and administrative arrangements. In practical terms in Australia, this meant establishing a special AIDS branch within the Health Advancement Division of the Community Health Department. AIDS issues must remain depoliticized to defuse adversary politics and keep leaders in a united front.

  14. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  15. Pulmonary complications of AIDS: radiologic features. [AIDS

    SciTech Connect

    Cohen, B.A.; Pomeranz, S.; Rabinowitz, J.G.; Rosen, M.J.; Train, J.S.; Norton, K.I.; Mendelson, D.S.

    1984-07-01

    Fifty-two patients with pulmonary complications of acquired immunodeficiency syndrome (AIDS) were studied over a 3-year period. The vast majority of the patients were homosexual; however, a significant number were intravenous drug abusers. Thirteen different organisms were noted, of which Pneumocystis carinii was by far the most common. Five patients had neoplasia. Most patients had initial abnormal chest films; however, eight patients subsequently shown to have Pneumocystis carinii pneumonia had normal chest films. A significant overlap in chest radiographic findings was noted among patients with different or multiple organisms. Lung biopsy should be an early consideration for all patients with a clinical history consistent with the pulmonary complications of AIDS. Of the 52 patients, 41 had died by the time this report was completed.

  16. High Output Piezo/Triboelectric Hybrid Generator

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-03-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA.cm-2, and average power density of ~4.44 mW.cm-2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.

  17. High Output Piezo/Triboelectric Hybrid Generator

    PubMed Central

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-01-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA·cm−2, and average power density of ~4.44 mW·cm−2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

  18. Potential output and the recent productivity decline

    SciTech Connect

    Tatom, J.A.

    1982-01-01

    Recent revisions in the measures of the nation's output and capital stock, as well as minor changes in procedures, have altered the Federal Reserve Bank of St. Louis' measures of potential output. The major conclusions of earlier Bank studies, however, have been unaffected by these changes. In particular, the growth of potential output has been sharply reduced by the 1973 to 1974 and 1979 to 1980 energy shocks and subsequent adjustments in the desired capital intensity of production. These effects have been confirmed by the re-estimation of earlier production function coefficients, and, more important, the confirmation of the prior empirical estimates in the latest round of energy price increases. The decline in the growth of potential output since 1973 has, in recent years, been acknowledged by the Council of Economic Advisers, (CEA), but through a trend reduction rather than through sharp temporary declines in 1974 to 1975 and 1979 to 1980 as implied here. Nonetheless, the level of potential output estimated by the CEA in recent years is little different from this Bank's estimate. The slowing in potential output masks a sharper reduction in the growth of productivity in recent years. A detailed analysis of productivity developments shows a marked deterioration in growth relative to past trends. In the measurement of potential output, this deterioration has been partially offset by a more rapid growth of both potential and actual employment. 17 references, 5 figures, 6 tables.

  19. High output piezo/triboelectric hybrid generator.

    PubMed

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-03-20

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA · cm(-2), and average power density of ~4.44 mW · cm(-2). The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.

  20. First Aid and Safety

    MedlinePlus

    ... First-Aid Kit Food Safety for Your Family Gun Safety Halloween Candy Hints Household Safety Checklists Household ... Climbing, and Grabbing Household Safety: Preventing Injuries From Firearms Household Safety: Preventing Injuries in the Crib Household ...

  1. HIV and AIDS

    MedlinePlus

    ... known as AIDS . HIV destroys a type of defense cell in the body called a CD4 helper ... are part of the body's immune system , the defense system that fights infections. When HIV destroys these ...

  2. AIDS: A National Dilemma.

    ERIC Educational Resources Information Center

    Issues in Science and Technology, 1987

    1987-01-01

    Contains excerpts from a special study on the AIDS epidemic by the Institute of Medicine and National Academy of Sciences. Presents an overview of the problem, outlines educational needs and public health measures, and identifies future research needs. (ML)

  3. Convulsions - first aid - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100212.htm Convulsions - first aid - series—Procedure, part 1 To use ... slide 2 out of 2 Overview When a seizure occurs, the main goal is to protect the ...

  4. First Aid: Burns

    MedlinePlus

    ... MORE ON THIS TOPIC Kitchen: Household Safety Checklist Fireworks Safety First Aid: Sunburn Firesetting Fire Safety Burns ... Being Safe in the Kitchen Finding Out About Fireworks Safety Playing With Fire? Dealing With Burns Fireworks ...

  5. Hearing Aid Tester

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Hearing aids often develop malfunctions that are not detected by the wearer. This is particularly true when the wearers are school-age children. Studies of selected groups showed that from 30 to more than 50 percent of school children were not getting adequate benefit from their hearing aids because of unrecognized malfunctions, usually low or dead batteries. This can be serious because hearing impairment retards a child's educational progress. NASA technology incorporated in the Hearing Aid Malfunction Detection Unit (HAMDU), the device pictured, is expected to provide an effective countermeasure to the childrens' hearing aid problem. A patent license has been awarded to a minority-owned firm, Hopkins International Company, a subsidiary of H. H. Aerospace Design Co., Inc., Elmford, New York. The company plans early commercial availability of its version of the device.

  6. First Aid: Croup

    MedlinePlus

    ... Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family Life First Aid & Safety Doctors & ... with each breath has a pale or bluish color around the mouth drools or has difficulty swallowing ...

  7. Computer Aided Creativity.

    ERIC Educational Resources Information Center

    Proctor, Tony

    1988-01-01

    Explores the conceptual components of a computer program designed to enhance creative thinking and reviews software that aims to stimulate creative thinking. Discusses BRAIN and ORACLE, programs intended to aid in creative problem solving. (JOW)

  8. HIV/AIDS Treatment

    MedlinePlus

    ... HIV/AIDS Influenza Malaria Respiratory Syncytial Virus (RSV) Tuberculosis Zika Virus Find a Funding Opportunity Opportunities & Announcements ... related co-infections, such as hepatitis, malaria, and tuberculosis. Treatment of HIV Infection In the early 1980s ...

  9. First Aid: Croup

    MedlinePlus

    ... difficulty swallowing becomes tired easily Think Prevention! Frequent hand washing and avoiding contact with people who have respiratory ... Aid: Coughing X-Ray Exam: Neck Why Is Hand Washing So Important? Coughing Croup Contact Us Print Resources ...

  10. HIV and AIDS

    MedlinePlus

    ... that causes the disease AIDS. HIV Hurts the Immune System People who are HIV positive have been tested ... to everyone in the world. When the person's immune system has weakened and more of the blood's T ...

  11. AIDS in Africa

    DTIC Science & Technology

    2006-03-09

    have recommended that Africans infected with HIV be treated with an antibiotic/ sulfa drug combination known as cotrimoxazole in order to prevent...response is the subject of much debate. An estimated 500,000 Africa AIDS patients were being treated with antiretroviral drugs in mid-2005, up from 150,000...whether drugs can be made widely accessible without costly health infrastructure improvements. U.S. concern over AIDS in Africa grew in the 1980s, as the

  12. Naval Tactical Decision Aids

    DTIC Science & Technology

    1989-09-01

    Strike Planning Aid ( ESPA ) . .V-14 5.4. Tactical Environmental Ship Routing (TESR) V-24 5.5. Chaff Prediction and Planning System (CHAPPS).. V-29...chapter four TDAS from TESS: NAVSAR, acAS program for search and rescue (SARjat sea; ESPA , the Environmental Strike Planning Aid; TESR, the Tactical...STATISTICS CURRENT LOCATION AND CHARACTERISTICS SATELLITE DATA CONVERSION CONSTANTS In 5.1, we give a brief history of TESS. The TDAS NAVSAR, ESPA

  13. AIDS and National Security

    DTIC Science & Technology

    2007-11-02

    the body loses its ability to fight off other infections like the flu or pneumonia that it could normally handle with ease.11 These infections are... children orphaned by AIDS in sub-Saharan Africa.32 Failing states are not able to provide care for these orphans so they are lured into crime or...four major program elements funded by USAID are primary prevention, caring for children affected by AIDS, home and community based care and treatment

  14. Design of hydraulic output Stirling engine

    NASA Technical Reports Server (NTRS)

    Toscano, W. M.; Harvey, A. C.; Lee, K.

    1983-01-01

    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency.

  15. Output-Isolation And Protection Circuit

    NASA Technical Reports Server (NTRS)

    Wagner, Charles A.; Kellogg, Gary V.

    1989-01-01

    Output-isolation circuit couples precise analog signals (-10 to +10 V, 0 to 20 kHz) from computer or from other electronic equipment to external electronic equipment that may be at different ground potential. Circuit functions in presence of common-mode voltages up to 2,500 Vac or 3,500 Vdc. To prevent damage from accidental connection of output leads to powerlines or other sources of high voltage, circuit includes features that protect input and output signal lines against normal-mode overvoltages up to 120 V ac or dc.

  16. Generalization ability of perceptrons with continuous outputs

    NASA Astrophysics Data System (ADS)

    Bös, S.; Kinzel, W.; Opper, M.

    1993-02-01

    In this paper we examine the influence of different input-output relations on the generalization ability of a single-layer perceptron. The input-output relations can be linear, binary, or sigmoid. With this choice we take into account most of the cases which are of present interest. The generalization problem will be realizable or unrealizable if the input-output relations for teacher and student are identical or not. We show that sometimes it can have a positive effect on the generalization ability, if one learns with errors.

  17. Cardiac output measurement in pediatric anesthesia.

    PubMed

    Skowno, Justin J; Broadhead, Michael

    2008-11-01

    Maintenance of cardiovascular stability is crucial to safe anesthetic practice, but measurement of cardiac output has been technically challenging, particularly in pediatric patients. Cardiovascular monitoring has therefore generally relied upon pressure-based measurements, as opposed to flow-based measurements. The measurement of cardiac output under anesthesia and in critical care has recently become easier as a result of new techniques of measurement. This article reviews the basic concepts of and rationale for cardiac output monitoring, and then describes the techniques available for monitoring in clinical practice.

  18. Methods in pharmacology: measurement of cardiac output

    PubMed Central

    Geerts, Bart F; Aarts, Leon P; Jansen, Jos R

    2011-01-01

    Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. The ‘holy grail’ for the measurement of cardiac output would be a method that is accurate, precise, operator independent, fast responding, non-invasive, continuous, easy to use, cheap and safe. This method does not exist today. In this review on cardiac output methods used in pharmacology, the Fick principle, indicator dilution techniques, arterial pulse contour analysis, ultrasound and bio-impedance are reviewed. PMID:21284692

  19. [Aids, physicians, Catholic Church].

    PubMed

    Pipino, Marica; Boldrini, Elena; Cristani, Alessandro

    2003-01-01

    The latest AIDS' congress (Barcelona) reminded the world this dramatic situation. The shown data are remarkable: 5 million people of new infected in 2001, 68 million people could die in the next 20 years because of AIDS and the biggest part of them is living in the South of the world. There are two different kind of AIDS: the AIDS of rich people (2% of infected ones), who can reach the modern therapies that changed the course of the disease now curable out of hospital, and the AIDS of poor ones, without therapies and future. The political-economic effort of Western governments, of global fund anti-AIDS and of non governmental organizations now is not able to answer to this emergency in the right way. The lacking sensibility of Western doctors and the inflexible position of Catholic Church about contraception make the situation more complicated. It's hopeful the overcoming of this position using a Catholic Church's precious concept: the distinction between "simpliciter" and "secundum quid" to agree the use of condoms in case of absolute need.

  20. Water resources and environmental input-output analysis and its key study issues: a review

    NASA Astrophysics Data System (ADS)

    YANG, Z.; Xu, X.

    2013-12-01

    Used to study the material and energy flow in socioeconomic system, Input-Output Analysis(IOA) had been an effective analysis tool since its appearance. The research fields of Input-Output Analysis were increasingly expanded and studied in depth with the development of fundamental theory. In this paper, starting with introduction of theory development, the water resources input-output analysis and environmental input-output analysis had been specifically reviewed, and two key study issues mentioned as well. Input-Occupancy-Output Analysis and Grey Input-Output Analysis whose proposal and development were introduced firstly could be regard as the effective complements of traditional IOA theory. Because of the hypotheses of homogeneity, stability and proportionality, Input-Occupancy-Output Analysis and Grey Input-Output Analysis always had been restricted in practical application inevitably. In the applied study aspect, with investigation of abundant literatures, research of water resources input-output analysis and environmental input-output analysis had been comprehensively reviewed and analyzed. The regional water resources flow between different economic sectors had been systematically analyzed and stated, and several types of environmental input-output analysis models combined with other effective analysis tools concluded. In two perspectives in terms of external and inland aspect, the development of water resources and environmental input-output analysis model had been explained, and several typical study cases in recent years listed respectively. By the aid of sufficient literature analysis, the internal development tendency and study hotspot had also been summarized. In recent years, Chinese literatures reporting water resources consumption analysis and virtue water study had occupied a large share. Water resources consumption analysis had always been the emphasis of inland water resources IOA. Virtue water study had been considered as the new hotspot of

  1. Coupling output of multichannel high power microwaves

    SciTech Connect

    Li Guolin; Shu Ting; Yuan Chengwei; Zhang Jun; Yang Jianhua; Jin Zhenxing; Yin Yi; Wu Dapeng; Zhu Jun; Ren Heming; Yang Jie

    2010-12-15

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  2. Memory-based parallel data output controller

    NASA Technical Reports Server (NTRS)

    Stattel, R. J.; Niswander, J. K. (Inventor)

    1984-01-01

    A memory-based parallel data output controller employs associative memories and memory mapping to decommutate multiple channels of telemetry data. The output controller contains a random access memory (RAM) which has at least as many address locations as there are channels. A word counter addresses the RAM which provides as it outputs an encoded peripheral device number and a MSB/LSB-first flag. The encoded device number and a bit counter address a second RAM which contains START and STOP flags to pick out the required bits from the specified word number. The LSB/MSB, START and STOP flags, along with the serial input digital data go to a control block which selectively fills a shift register used to drive the parallel data output bus.

  3. 325 and 610 MHz Radio Counterparts of SNR G353.6-0.7 a.k.a. HESS J1731-347

    NASA Astrophysics Data System (ADS)

    Nayana, A. J.; Chandra, Poonam; Roy, Subhashis; Green, David A.; Acero, Fabio; Lemoine-Goumard, Marianne; Marcowith, Alexandre; Ray, Alak K.; Renaud, Matthieu

    2017-01-01

    HESS J1731-347 a.k.a. SNR G353.6-0.7 is one of the five known shell-type supernova remnants (SNRs) emitting in the very high energy (VHE, Energy > 0.1 TeV) γ-ray domain. We observed this TeV SNR with the Giant Metrewave Radio Telescope (GMRT) in 1390, 610 and 325 MHz bands. In this paper, we report the discovery of 325 and 610 MHz radio counterparts of the SNR HESS J1731-347 with the GMRT. Various filaments of the SNR are clearly seen in the 325 and 610 MHz bands. However, the faintest feature in the radio bands corresponds to the peak in VHE emission. We explain this anti-correlation in terms of a possible leptonic origin of the observed VHE γ-ray emission. We determine the spectral indices of the bright individual filaments, which were detected in both the 610 and the 325 MHz bands. Our values range from -1.11 to -0.15, consistent with the non-thermal radio emission. We also report a possible radio counterpart of a nearby TeV source HESS J1729-345 from the 843 MHz Molonglo Galactic Plane Survey and the 1.4 GHz Southern Galactic Plane Survey maps. The positive radio spectral index of this possible counterpart suggests a thermal origin of the radio emission of this nearby TeV source.

  4. 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.

  5. The chromatin remodeling and mRNA splicing functions of the Brahma (SWI/SNF) complex are mediated by the SNR1/SNF5 regulatory subunit.

    PubMed

    Zraly, Claudia B; Dingwall, Andrew K

    2012-07-01

    Nucleosome remodeling catalyzed by the ATP-dependent SWI/SNF complex is essential for regulated gene expression. Transcriptome profiling studies in flies and mammals identified cell cycle and hormone responsive genes as important targets of remodeling complex activities. Loss of chromatin remodeling function has been linked to developmental abnormalities and aggressive cancers. The Drosophila Brahma (Brm) SWI/SNF complex assists in reprogramming and coordinating gene expression in response to ecdysone hormone signaling at critical points during development. We used RNAi knockdown in cultured cells and transgenic flies, and conditional mutant alleles to identify unique and important functions of two conserved Brm complex core subunits, SNR1/SNF5 and BRM/SNF2-SWI2, on target gene regulation. Unexpectedly, we found that incorporation of a loss of function SNR1 subunit led to alterations in RNA polymerase elongation, pre-mRNA splicing regulation and chromatin accessibility of ecdysone hormone regulated genes, revealing that SNR1 functions to restrict BRM-dependent nucleosome remodeling activities downstream of the promoter region. Our results reveal critically important roles of the SNR1/SNF5 subunit and the Brm chromatin remodeling complex in transcription regulation during elongation by RNA Polymerase II and completion of pre-mRNA transcripts that are dependent on hormone signaling in late development.

  6. Anomalous light output from lightning dart leaders

    NASA Technical Reports Server (NTRS)

    Guo, C.; Krider, E. P.

    1985-01-01

    About 5 percent of the multiple-stroke cloud-to-ground lightning discharges recorded at the NASA Kennedy Space Center during the summer of 1981 contained dart leaders that produced an unusually large light output. An analysis of these cases indicates that the average peak light output per unit length in the leader may be comparable to or even exceed that of the return stroke that follows.

  7. Surface emitting lasers with combined output

    NASA Technical Reports Server (NTRS)

    Carlin, Donald B. (Inventor)

    1990-01-01

    Surface emitting lasers are laterally aligned and coupled together and also have their light output signals combined. This results in greater phase and frequency coherency and narrower and reduced amplitude sidelobes. Preferably, not more than two lasers are longitudinally aligned along the same axis for still greater coherency compared with adding the light output signals of more than two longitudinally aligned lasers. The lasers can be of the DH-LOC type or of the QW type.

  8. The Student Guide: Financial Aid.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC. Student Financial Assistance.

    This publication explains what federal student financial aid is and what types of student aid are available. Two introductory sections present: federal student aid at-a-glance (what it is, who gets it, and how to get it) and finding out about student aid. The first section presents general information on the following subjects: student…

  9. Mommy, Daddy--What's AIDS?

    ERIC Educational Resources Information Center

    National Association of Pediatric Nurse Associates and Practitioners, Cherry Hill, NJ.

    This brochure is designed to help parents answer the questions that their children may ask them about Acquired Immune Deficiency Syndrome (AIDS) and the Human Immuno Deficiency Virus (HIV), the virus that causes AIDS. It provides basic information about AIDS and HIV, as well as sources for further information, such as the National AIDS Hotline. It…

  10. The First Aid Training Picture.

    ERIC Educational Resources Information Center

    Moore, Ian

    2000-01-01

    Discusses the history of first aid training provisions in the United Kingdom with respect to the outdoor industry, what to look for in a first aid training provider, an experiential model of first aid training, and the current National Governing Body requirements for first aid training for various types of coaches and instructors. (TD)

  11. Answering Your Questions about AIDS.

    ERIC Educational Resources Information Center

    Kalichman, Seth C.

    This book focuses on AIDS education and answers 350 commonly asked questions about Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) taken from questions addressed to two major urban AIDS hotlines (Milwaukee, Wisconsin, and Houston, Texas). Chapter 1, "HIV - The Virus That Causes AIDS," discusses: the HIV…

  12. 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

  13. 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.

  14. Women and AIDS: introduction.

    PubMed

    Krieger, N; Margo, G

    1991-01-01

    Around the world, more and more women--principally poor women of color--are being diagnosed with and are dying of AIDS, the acquired immune deficiency syndrome. Yet, effective and appropriate prevention programs for women are sorely missing from the global program to control AIDS. To help us understand why this gap exists, and what we must do to close it, the three articles in this issue focus on women and AIDS. Examining the situation in such countries as Zimbabwe and South Africa, as well as in other economically underdeveloped and developed regions, the authors argue that women with the least control over their bodies and their lives are at greatest risk of acquiring AIDS. For example, the high rate of infection among women in Africa cannot be understood apart from the legacy of colonialism (including land expropriation and the forced introduction of a migrant labor system) and the insidious combination of traditional and European patriarchal values. Only by recognizing the socioeconomic and cultural determinants of both disease and sexual behavior, and only by incorporating these insights into our AIDS prevention programs, will we be able to curb the spread of this lethal disease.

  15. AIDS in Africa.

    PubMed

    Mokhobo, D

    1989-03-01

    Numerous cultural practices and attitudes in Africa represent formidable obstacles to the prevention of the further spread of acquired immunodeficiency syndrome (AIDS). Polygamy and concubinage are still widely practiced throughout Africa. In fact, sexual promiscuity on the part of males is traditionally viewed as positive--a reflection of male supremacy and male sexual prowess. The disintegration of the rural African family, brought about by urbanization, the migrant labor system, and poverty, has resulted in widespread premarital promiscuity. Contraceptive practices are perceived by many as a white conspiracy aimed at limiting the growth of the black population and thereby diminishing its political power. Condom use is particularly in disfavor. Thus, AIDS prevention campaigns urging Africans to restrict the number of sexual partners and to use condoms are unlikely to be successful. Another problem is that most Africans cannot believe that AIDS is sexually linked in that the disease does not affect the sex organs as is the case with other sexually transmitted diseases. The degree to which African governments are able to allocate resources to AIDS education will determine whether the epidemic can be controlled. Even with a massive outpouring of resources, it may be difficult to arouse public alarm about AIDS since Africans are so acclimated to living with calamities of every kind.

  16. Scaffolding Strategies during Repeated Storybook Reading: An Extension Using a Voice Output Communication Aid

    ERIC Educational Resources Information Center

    Bellon-Harn, Monica L.; Harn, William E.

    2008-01-01

    Adult scaffolding during repeated storybook reading was developed for children who use speech as their primary expressive modality, but through the use of augmentative and alternative communication, it has been extended to children who do not have functional, intelligible speech. Scaffolding strategies during repeated storybook reading and during…

  17. Rapid Message Composition for Large Vocabulary Speech Output Aids: A Review of the Possibilities.

    ERIC Educational Resources Information Center

    Damper, R. I.

    1986-01-01

    Three types of rapid message composition for non-speaking persons, classified according to keyboard, are described: sequential keyboard, "semantic" input through iconic representation, and chord keyboard. The strengths, drawbacks, and potential of each type are discussed for a user population with good keying ability and normal cognitive and…

  18. Cortical and corticospinal output modulations during reaching movements with varying directions and magnitudes of interaction torques.

    PubMed

    Asmussen, M J; Bailey, A Z; Nelson, A J

    2015-12-17

    The neural command required to coordinate a multi-joint movement is inherently complex. During multi-joint movement of the limb, the force created from movement at one joint may create a torque at a second joint known as an interaction torque. Interaction torques may be assistive or resistive thereby aiding or opposing the motion of the second joint, respectively. For movement to be effectively controlled, the central nervous system should modulate neural output to the muscles to appropriately account for interaction torques. The present study examined the neural output from the primary motor cortex before and during reaching movements that required different combinations of assistive and resistive interaction torques occurring at the shoulder and elbow joints. Using transcranial magnetic stimulation to probe neural output from the primary motor cortex, results indicate that corticospinal output controlling the upper arm is related to resistive interaction torques occurring at the shoulder joint. Further, cortical output to bi-articular muscles is associated with interaction torque and this may be driven by the fact that these muscles are in an advantageous position to control torques produced between inter-connection segments. Humans have a tendency to avoid reaching movements that involve resistive interaction torques and this may be driven by the requirement of increased neural output associated with these movements.

  19. Compact Relativistic Magnetron with Output Mode Converter

    NASA Astrophysics Data System (ADS)

    Andreev, Andrey; Fuks, Mikhail; Schamiloglu, Edl

    2003-10-01

    We consider a relativistic magnetron in which all of the resonators of the anode block are smoothly continued onto a conical antenna up to the radius corresponding to the cutoff frequency of the radiated wave in a cylindrical waveguide. Such a magnetron is capable of high output power, is compact, has a high resistance to microwave breakdown, is able to work with extremely high currents, and has the possibility of forming desirable output radiation patterns. The magnetic field can be provided by a small solenoid over the resonant system, which is a much smaller volume than is required for the Helmholtz coils used in traditional relativistic magnetrons. The maximum size of this magnetron is the aperture of the horn antenna. The unique aspect of such a design is the possibility of using the horn antenna for conversion of the operating mode to lower order modes, including the TE_11 mode, which is radiated as a narrow wave beam. For a magnetron operating in π-mode, the mode converter comprises a continuation of the resonantor blocks onto the horn for those resonators that correspond to the symmetry of the output mode. For example, in order to provide Gaussian mode output only two diametrically opposite resonators of even-numbered resonators must be continued onto the horn. In this case the aperture of the horn antenna can be close to the cut-off diameter for the TE_11 mode, and the output power is limited only by breakdown of the output window. In this presentation results of preliminary calculations of the magnetron with output mode converters are presented.

  20. AIDS in Colombia.

    PubMed

    Boshell, J; Gacharná, M G; García, M; Jaramillo, L S; Márquez, G; Fergusson, M M; González, S; Prada, E Y; de Rangel, R; de Cabas, R

    1989-01-01

    Between January 1984 and December 1987 a total of 178 AIDS cases were reported to the Colombian Ministry of Health. The location of these cases suggests that the human immunodeficiency virus (HIV) is widely distributed in Colombia. Most of those afflicted (97%) have been adult males. HIV seroprevalence studies of selected population groups revealed the highest antibody prevalence (5.65% in females, 22.5% in males) among individuals involved in high-risk behaviors who participated in a free AIDS testing program. High prevalences (from 0.6% to 3.9% in females, and 14.6% to 15.9% in males) were also found in patients (primarily female prostitutes and male homosexuals) attending clinics for sexually transmitted diseases in several urban areas. The number of AIDS cases in Colombia has doubled or tripled annually since reporting began in 1984, a pattern similar to that observed worldwide.

  1. Recapture training aid.

    SciTech Connect

    Pacheco, James Edward

    2004-08-01

    The breacher's training aid described in this report was designed to simulate features of magazine and steel-plate doors. The training aid enables breachers to practice using their breaching tools on components that they may encounter when attempting to enter a facility. Two types of fixtures were designed and built: (1) a large fixture incorporates simulated hinges, hasps, lock shrouds, and pins, and (2) a small fixture simulates the cross section of magazine and steel-plate doors. The small fixture consists of steel plates on either side of a structural member, such as an I-beam. The report contains detailed descriptions and photographs of the training aids, assembly instructions, and drawings.

  2. Design of a C-band relativistic extended interaction klystron with coaxial output cavity

    NASA Astrophysics Data System (ADS)

    Yang, Wu; Zhao, De-Kui; Chen, Yong-Dong

    2015-07-01

    In order to overcome the disadvantages of conventional high frequency relativistic klystron amplifiers in power capability and RF conversion efficiency, a C-band relativistic extended interaction klystron amplifier with coaxial output cavity is designed with the aid of PIC code MAGIC. In the device, disk-loaded cavities are introduced in the input and intermediate cavity to increase the beam modulation depth, and a coaxial disk-loaded cavity is employed in the output cavity to enhance the RF conversion efficiency. In PIC simulation, when the beam voltage is 680 kV and current is 4 kA, the device can generate 1.11 GW output power at 5.64 GHz with an efficiency of 40.8%.

  3. H-/H∞ fault detection observer design based on generalized output for polytopic LPV system

    NASA Astrophysics Data System (ADS)

    Zhou, Meng; Rodrigues, Mickael; Shen, Yi; Theilliol, Didier

    2017-01-01

    This paper proposes an H-/H∞ fault detection observer design method by using generalized output for a class of polytopic linear parameter-varying (LPV) system. First, with the aid of the relative degree of output, a new output vector is generated by gathering the original and its time derivative. The actuator fault is introduced into the measurement equation of the new system. An H-/H∞ observer is designed for the new LPV polytopic system to guarantee the robustness against disturbances and to improve the fault sensitivity, simultaneously. The existence conditions of the H-/H∞ observer are given and solved by a set of linear matrix inequalities (LMIs). Finally simulation results are given to illustrate the effectiveness of the proposed method.

  4. Catalog of the H-alpha + N II forbidden-line emission features in the Kepler SNR

    SciTech Connect

    Dodorico, S.; Bandiera, R.; Danziger, J.; Focardi, P.

    1986-06-01

    A deep image of the Kepler SNR has been obtained in the light of H-alpha + N II forbidden-line with the faint object spectrograph and camera (EFOSC) and a CCD detector at the ESO 3.6 m telescope. The visibility of the optically emitting knots of ionized gas has been greatly enhanced by subtraction of the continuum radiation. Features as faint as 2 percent of the night-sky brightness have been identified and a half-shell of emission is clearly revealed. The total H-alpha luminosity of the ionized gas is estimated to be 8.3 x 10 to the 45th photons/s at a distance of 5 kpc implying a mass of ionized hydrogen of about 0.02 solar mass. An automatic searching program has been used to identify and list individual emission features in the continuum-subtracted image. A catalog with accurate celestial positions and approximate fluxes for 64 emission-line knots is given. 13 references.

  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.

  6. IDEAL CURRENT PATTERNS YIELDING OPTIMAL SNR AND SAR IN MAGNETIC RESONANCE IMAGING: COMPUTATIONAL METHODS AND PHYSICAL INSIGHTS

    PubMed Central

    Lattanzi, Riccardo; Sodickson, Daniel K.

    2011-01-01

    At high and ultra-high magnetic field strengths, understanding interactions between tissues and the electromagnetic fields generated by radiofrequency (RF) coils becomes crucial for safe and effective coil design, as well as for insight into limits of performance. In this work we present a rigorous electrodynamic modeling framework, using dyadic Green’s functions, to derive the electromagnetic field in homogeneous spherical and cylindrical samples resulting from arbitrary surface currents in the presence or absence of a surrounding RF shield. We show how to calculate ideal current patterns which result in the highest possible signal to noise ratio (“ultimate intrinsic signal to noise ratio (SNR)”) or the lowest possible RF power deposition (“ultimate intrinsic specific absorption rate (SAR)”) compatible with electrodynamic principles. We identify familiar coil designs within optimal current patterns at low to moderate field strength, thereby establishing and explaining graphically the near-optimality of traditional surface and volume quadrature designs. We also document the emergence of less familiar patterns, e.g. involving substantial electric as well as magnetic dipole contributions, at high field strength. Performance comparisons with particular coil array configurations demonstrate that optimal performance may be approached with finite arrays if ideal current patterns are used as a guide for coil design. PMID:22127735

  7. Smooth extraction of SVC fine-granular SNR scalable videos with a virtual-GOP-based rate-distortion modeling

    NASA Astrophysics Data System (ADS)

    Sun, Jun; Gao, Wen; Zhao, Debin

    2008-01-01

    Fine-Granular SNR scalable (FGS) technologies in H.264/AVC-based scalable video coding (SVC) provide a flexible and effective foundation for scaling FGS enhancement layer (EL) to accommodate different and variable network capacities. To support smooth quality extraction of SVC FGS videos, it's important to obtain the Rate-Distortion (R-D) function of each picture or group of pictures (GOP). In this paper, firstly, we introduce the R-D analysis of SVC FGS coding in our prior work. Then, with the analysis and models, we present virtual GOP concept and a virtual-GOP-based packet scheduling algorithm is proposed to acquire the optimal packet scheduling sequence in a virtual GOP. Based on the packet scheduling algorithm and the R-D analysis of FGS EL, an effective and flexible D-R model is proposed to describe the D-R function of the virtual GOP. Then, with the R-D model of virtual GOPs, a practical non-search algorithm for smooth quality reconstruction is introduced. Compared to the quality layer method, the reconstructed video quality is improved not only objectively but also subjectively.

  8. Evaluation of a new approach for speech enhancement algorithms in hearing aids.

    PubMed

    Montazeri, Vahid; Khoubrouy, Soudeh A; Panahi, Issa M S

    2012-01-01

    Several studies on hearing impaired people who use hearing aid reveal that speech enhancement algorithms implemented in hearing aids improve listening comfort. However, these algorithms do not improve speech intelligibility too much and in many cases they decrease the speech intelligibility, both in hearing-impaired and in normally hearing people. In fact, current approaches for development of the speech enhancement algorithms (e.g. minimum mean square error (MMSE)) are not optimal for intelligibility improvement. Some recent studies investigated the effect of different distortions on the enhanced speech and realized that by controlling the amplification distortion, the intelligibility improves dramatically. In this paper, we examined, subjectively and objectively, the effects of amplification distortion on the speech enhanced by two algorithms in three background noises at different SNR levels.

  9. Symmetric RBF classifier for nonlinear detection in multiple-antenna-aided systems.

    PubMed

    Chen, Sheng; Wolfgang, Andreas; Harris, Chris J; Hanzo, Lajos

    2008-05-01

    In this paper, we propose a powerful symmetric radial basis function (RBF) classifier for nonlinear detection in the so-called "overloaded" multiple-antenna-aided communication systems. By exploiting the inherent symmetry property of the optimal Bayesian detector, the proposed symmetric RBF classifier is capable of approaching the optimal classification performance using noisy training data. The classifier construction process is robust to the choice of the RBF width and is computationally efficient. The proposed solution is capable of providing a signal-to-noise ratio (SNR) gain in excess of 8 dB against the powerful linear minimum bit error rate (BER) benchmark, when supporting four users with the aid of two receive antennas or seven users with four receive antenna elements.

  10. Response requirements as constraints on output.

    PubMed

    Zeiler, M D; Buchman, I B

    1979-07-01

    Two experiments studied how added response requirements affected fixed-interval schedule performance. Experiment 1 involved tandem fixed-interval fixed-ratio schedules, and Experiment 2 studied conjunctive fixed-interval fixed-ratio schedules. In both, pigeons' output, defined as overall response rate or as responses during the interval, first increased and then decreased as the ratio was raised. With small ratio requirements, the frequency of reinforcement in time either did not change or decreased slightly. With progressively larger ratios, reinforcement frequency decreased consistently. Alternative explanations were discussed. The first, a reinforcement theory account, was that response strength is an increasing monotonic function of both the response requirement and reinforcement frequency, and the bitonic output function represents interacting effects. Increases in the response requirement accompanied by small changes in reinforcement frequency enhance output, but further increases result in large enough decrements in reinforcement frequency so that output is lowered. The second explanation does not view reinforcement as a basic process but, instead, derives from concepts of economics and conservation. Organisms allocate their behavior among alternatives so as to maximize value, where value is a function of the responses that can occur in a given situation under the set of restrictions imposed by particular schedules. One form of this theory explicitly predicts that output is a bitonic function of ratio requirements in simple ratio schedules. However, it was not clear that this model could explain the present effects involving joint ratio and interval schedule restrictions.

  11. Output Synchronization of Nonidentical Linear Multiagent Systems.

    PubMed

    Wu, Yuanqing; Su, Hongye; Shi, Peng; Lu, Renquan; Wu, Zheng-Guang

    2017-01-01

    In this paper, the problem of output synchronization is investigated for the heterogeneous network with an uncertain leader. It is assumed that parameter perturbations influence the nonidentical linear agents, whose outputs are controlled to track the output of an uncertain leader. Based on the hierarchical structure of the communication graph, a novel control scheme is proposed to guarantee the output synchronization. As there exist parameter uncertainties in the models of the agents, the internal model principle is used to gain robustness versus plant parameter uncertainties. Furthermore, as the precise model of the leader is also not available, the adaptive control principle is adopted to tune the parameters in the local controllers. The developed new technique is able to simultaneously handle uncertainties in the follower parameters as well as the leader parameters. The agents in the upper layers will be treated as the exosystems of the agents in the lower layers. The local controllers are constructed in a sequential order. It is shown that the output synchronization can be achieved globally asymptotically and locally exponentially. Finally, a simulation example is given to illustrate the effectiveness and potential of the theoretic results obtained.

  12. Linear summation of cat motor cortex outputs.

    PubMed

    Ethier, Christian; Brizzi, Laurent; Darling, Warren G; Capaday, Charles

    2006-05-17

    Recruitment of movement-related muscle synergies involves the functional linking of motor cortical points. We asked how the outputs of two simultaneously stimulated motor cortical points would interact. To this end, experiments were done in ketamine-anesthetized cats. When prolonged (e.g., 500 ms) trains of intracortical microstimulation were applied in the primary motor cortex, stimulus currents as low as 10-20 microA evoked coordinated movements of the contralateral forelimb. Paw kinematics in three dimensions and the electromyographic (EMG) activity of eight muscles were simultaneously recorded. We show that the EMG outputs of two cortical points simultaneously stimulated are additive. The movements were represented as displacement vectors pointing from initial to final paw position. The displacement vectors resulting from simultaneous stimulation of two cortical points pointed in nearly the same direction as the algebraic resultant vector. Linear summation of outputs was also found when inhibition at one of the cortical points was reduced by GABAA receptor antagonists. A simple principle emerges from these results. Notwithstanding the underlying complex neuronal circuitry, motor cortex outputs combine nearly linearly in terms of movement direction and muscle activation patterns. Importantly, simultaneous activation does not change the nature of the output at each point. An additional implication is that not all possible movements need be explicitly represented in the motor cortex; a large number of different movements may be synthesized from a smaller repertoire.

  13. AIDS and tuberculosis.

    PubMed

    Morales Suárez-Valera, M M; Llopis González, A; Ballester Calabuig, M L

    1993-03-01

    Between 1985-1989 were diagnosed 376 cases of TBC in "La Fe" hospital in Valencia. 36 of this cases also had AIDS. We have carried out a compared study among the 340 cases of TBC and the 36 cases of AIDS+TBC. In this way we have described the social and work conditions of both groups, the hospitalization, the associated pathologies, the different risk factors, the different characteristics of the disease in each group of TBC, the diagnoses methods and the treatment of each case.

  14. PV output smoothing with energy storage.

    SciTech Connect

    Ellis, Abraham; Schoenwald, David Alan

    2012-03-01

    This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.

  15. Visual Speech-Training Aid for the Deaf

    NASA Technical Reports Server (NTRS)

    Miller, Robert J.

    1987-01-01

    Teaching deaf to speak aided by electronic system provides striking colored, pictorial representation of sound; energy at different frequencies as function of time. Other modalities, such as nasality, intra-oral pressure, and lip-muscle contraction, pictorialized simultaneously. Use of standard components, including personal microcomputer, helps reduce cost below prior voice-training systems. Speech-training system, microphone output separated by filters into narrow frequency bands, changed into digital signals, formatted by computer, and displayed on television screen. Output from other sensors displayed simultaneously or screen split to allow sound produced by student to be compared with that of teacher.

  16. Visual aid for the hearing impaired

    NASA Astrophysics Data System (ADS)

    Jhabvala, Murzban D.; Lin, Hung C.

    1991-07-01

    A multichannel electronic visual aid device which is able to signal to the user whether sound is coming from the left or right, front or back, or both is presented. For the plurality of channels, which may operate in pairs, the sound is picked up by a respective microphone and amplified and rectified into a DC voltage. The DC voltage is next fed to an analog to digital converter and then to a digital encoder. The binary code from the encoder is coupled into a logic circuit where the binary code is decoded to proved a plurality of output levels which are used to drive an indicator which, in turn, provides a visual indication of the sound level received. The binary codes for each pair of channels are also fed into a digital comparator. The output of the comparator is used to enable the logic circuits of the two channels such that if, for example, the signal coming from the right is louder than that coming from the left, the output of the logic unit of the right channel will be enabled and the corresponding indicator activated, indicating the sound source on the right. An indication of the loudness is also provided. One embodiment of the invention may be carried by the hearing impaired or deaf, as a system which is embedded into eye glasses or a cap. Another embodiment of the invention may be integrated with a vehicle to give a hearing impaired or deaf driver a warning, with a directional indication, that an emergency vehicle is in the vicinity. In this second embodiment, the emergency vehicle transmits a radio frequency signal which would be used as an enabling signal for the visual aid device to avoid false alarms from traffic and other sound sources in the vicinity of the driver's vehicle.

  17. Approximations of nonlinear systems having outputs

    NASA Technical Reports Server (NTRS)

    Hunt, L. R.; Su, R.

    1985-01-01

    For a nonlinear system with output derivative x = f(x) and y = h(x), two types of linearizations about a point x(0) in state space are considered. One is the usual Taylor series approximation, and the other is defined by linearizing the appropriate Lie derivatives of the output with respect to f about x(0). The latter is called the obvservation model and appears to be quite natural for observation. It is noted that there is a coordinate system in which these two kinds of linearizations agree. In this coordinate system, a technique to construct an observer is introduced.

  18. First aid kit

    MedlinePlus

    ... bandages (Band-Aid or similar brand); assorted sizes Aluminum finger splints Elastic (ACE) bandage for wrapping wrist, ... to reduce contamination risk Save-A-Tooth storage device in case a tooth is broken or knocked out; ... equipment, and medical supplies. In: Auerbach PS, ed. Auerbach: Wilderness Medicine . ...

  19. Machine Aids to Translation.

    ERIC Educational Resources Information Center

    Brinkmann, Karl-Heinz

    1981-01-01

    Describes the TEAM Program System of the Siemens Language Services Department, particularly the main features of its terminology data bank. Discusses criteria to which stored terminology must conform and methods of data bank utilization. Concludes by summarizing the consequences that machine-aided translation development has had for the…

  20. Good Teaching Aids.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of 14 Audubon Nature Bulletins with these titles: Schoolyard Laboratories, How to Lead a Field Trip, Natural Resources in the City, Mysteries of Bird Migration, Rock Stories and How to Read Them, The Ground Water Table, The Terrarium, Some Adventures With Wild Plants Outdoors and Indoors, Plant Propagation in the…

  1. More than First Aid

    ERIC Educational Resources Information Center

    Schoessler, Sally

    2011-01-01

    The school nurse is an important member of the school team since school health services keep students in school, in the classroom, and ready to learn. Although school nurses are often seen as the people who deliver first aid at school, their role is much deeper and has such breadth that only a registered, professional nurse has the skill set to…

  2. Instructional Aide Program.

    ERIC Educational Resources Information Center

    Thomson, Henry

    The Instructional Aide Program (Shoreline Community College, Seattle, Washington) is a flexible curriculum designed to prepare students to meet the paraprofessional manpower needs of several kinds of institution. It was prepared after consultation with representatives of the schools, the YMCA, and the country park system. Other agencies still to…

  3. Management of Student Aid.

    ERIC Educational Resources Information Center

    Nevin, Jeanne, Ed.

    The principles, practices, responsibilities, and controls in student financial aid are described in this manual. It traces the flow of funds, management activities, and legal issues as they occur in the process. The emphasis is on sound management principles of a general and permanent nature rather than on specific government requirements that may…

  4. Computer Aided Manufacturing.

    ERIC Educational Resources Information Center

    Insolia, Gerard

    This document contains course outlines in computer-aided manufacturing developed for a business-industry technology resource center for firms in eastern Pennsylvania by Northampton Community College. The four units of the course cover the following: (1) introduction to computer-assisted design (CAD)/computer-assisted manufacturing (CAM); (2) CAM…

  5. Coil Welding Aid

    NASA Technical Reports Server (NTRS)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  6. Parent Hearing Aid Experiences

    ERIC Educational Resources Information Center

    Munoz, Karen; Roberts, Mallory; Mullings, Day; Harward, Richard

    2012-01-01

    This study addresses parent experiences in obtaining and managing hearing aids for their young child. The purpose was to identify challenges parents encounter to determine what state agencies can do to improve parent access to amplification. Data were collected July through September of 2010; 40 parents of children ages birth to 3 years old…

  7. AIDS: The Second Decade.

    ERIC Educational Resources Information Center

    Miller, Heather G., Ed.; And Others

    This report reviews the course of the Acquired Immune Deficiency Syndrome (AIDS) epidemic and its current status, examining changing patterns of sexual behavior and intravenous drug use, the distribution of cases of human immunodeficiency virus (HIV) infection, and the results of intervention efforts under way. It also discusses prevention…

  8. Impact Aid Program.

    ERIC Educational Resources Information Center

    Office of Elementary and Secondary Education (ED), Washington, DC.

    Impact Aid is a federal formula grant program designed to assist local school districts that have lost property tax revenue due to the presence of tax-exempt federal property or that have experienced increased expenditures due to the enrollment of federally connected children. Federally connected children are those whose parents pay minimal or no…

  9. AIDS Researcher Gives Retrospective

    ERIC Educational Resources Information Center

    Hawkins, B. Denise

    2011-01-01

    Nearly 30 years ago, renowned immunologist James E.K. Hildreth, M.D., Ph.D., was compelled to start researching the virus that causes AIDS. He marveled at its enigma and was pressed into action by its ability to cut lives short and devastate communities. The disease set him on a course of medical inquiry that has included biomedical breakthroughs…

  10. Newspaper Lesson Aids.

    ERIC Educational Resources Information Center

    Communication: Journalism Education Today (C:JET), 1986

    1986-01-01

    Provides photocopy-ready lesson aids on story ideas, interviewing, inverted pyramid writing style, newswriting, sports/scavenger hunt, finding feature material, identifying feature leads, feature lead selection, evaluating feature leads, compiling survey material, cutlines, headlines, paste-up rules, advertising, final semester project, newspaper…

  11. Computer Aided Art Major.

    ERIC Educational Resources Information Center

    Gibson, Jim

    The Computer Aided Art program offered at Northern State State University (Aberdeen, South Dakota), is coordinated with the traditional art major. The program is designed to familiarize students with a wide range of art-related computer hardware and software and their applications and to prepare students for problem-solving with unfamiliar…

  12. First Aid: Dehydration

    MedlinePlus

    ... Aid: Heat Illness Sun Safety Dehydration Diarrhea Vomiting Word! Dehydration What's the Big Sweat About Dehydration? How to Be Safe When You're in the Sun What's Sweat? Dehydration Is It Important to Drink a Lot of Water? Contact Us Print Resources Send to a Friend ...

  13. Job Aids and Motivation.

    ERIC Educational Resources Information Center

    Grau, Joseph A.

    1986-01-01

    Suggests job aids have motivational benefits and discusses three ways in which they positively affect motivation: increases worker's confidence of success and amount of effort they are willing to invest in attempting tasks; increases expectancy while decreasing amount of motivation needed; and reinforces task importance. (MBR)

  14. First Aid Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2011-01-01

    This article describes a challenge wherein students will be asked to design a portable first aid kit that is normally carried in a recreational vehicle (RV), but can also be hand-carried or backpacked off road for distances of approximately 1-2 miles. This can be a very practical challenge for the students because it touches everyone. Everybody…

  15. [Post-transfusional AIDS].

    PubMed

    Azzini, M; Maccabruni, A; Marcellini, M; Michelone, G; Dei Cas, A

    1987-01-01

    Two cases of post-transfusional AIDS in two premature babies who received blood of the same seropositive donor, are reported. The risk of the susceptibility to HIV infection of these patients, in relation to the immaturity of immune system and to the transfusional treatment often necessary in premature newborns, is stressed.

  16. AIDS and society.

    PubMed

    Singh, N K

    1991-08-01

    Noting the hysteria caused by an outbreak of AIDS among intravenous drug users in the state of Manipur, India, the author discusses the social and emotional aspects of the epidemic. Local media has been Manipur's main source of information concerning the outbreak, but this information has often been misleading and has served to stir up fear and hatred of HIV carriers. Many have even begun talking about an Isolation Centre. The author, the director of a drug rehabilitation center, relates his experiences in counseling 50 intravenous drug users on the subject of AIDS. He discovered that the group had very poor knowledge about the disease. When told about AIDS, they became alarmed at the possibility of dying. 1/2 of the group swore to take revenge on those who had introduced them to drugs, but the other 1/2 showed a more positive attitude, saying that they would like to help other drug addicts. The author also describes the case history of a patient who had succeeded in staying off of drugs for 8 months. HIV screening, however, revealed that the young man was seropositive. Somehow, a local newspaper got a hold of this information and published his name as a seropositive along with the names of others. Distraught by this, the young man returned to drugs. The author stresses that revealing the names of HIV carriers serves no social purpose, and in fact, only makes the problem worse. He recommends the following for dealing with the outbreak of AIDS: 1) intensive public health education on AIDS with the aim or removing unwarranted fears; 2) education to prevent drug addiction; 3) counselling to parents of drug addicts; and 4) the establishment of Seropositive Anonymous, an organization designed to help carriers deal with their problems.

  17. An Eye-Blinking-Based Beamforming Control Protocol for Hearing Aid Users With Neurological Motor Disease or Limb Amputation.

    PubMed

    Yoon, Jungmin; Nam, Kyoung Won; Lee, Jun Chang; Jang, Dong Pyo; Kim, In Young

    2017-02-01

    For hearing-impaired individuals with neurological motor deficits or finger/arm amputation due to accident or disease, hearing aid adjustment using a conventional finger manipulation-based remote controller is unavailable, and a more dedicated, hands-free alternative is required. In this study, we propose an eye-blinking-based beamforming control scheme for hearing aid users. Three electroencephalogram signals measured around the ears were utilized to detect eye-blinking patterns based on a three-layer artificial neural network. The performance of the proposed control scheme was evaluated by both subjective experiments and objective index comparison tests in simulated situations. Experimental results from the subjective test demonstrated that without the pretraining phase, the accuracy and latency time were 68.57 ± 18.50% and 10.06 ± 0.94 s, respectively; in contrast, after the pretraining phase, both the accuracy and latency time were improved to 91.00 ± 4.69% and 8.60 ± 1.05 s, respectively. In index comparison tests, the proposed control scheme exhibited improvements in the signal-to-noise ratio (SNR) as well as the segmental SNR in all tested situations, as compared to a conventional forward-focusing beamforming algorithm. We believe that the proposed control scheme provides a novel, hands-free way in which to control the operation of hearing aids for hearing-impaired patients with additional motor deficits or amputation.

  18. Porous radiant burners having increased radiant output

    DOEpatents

    Tong, Timothy W.; Sathe, Sanjeev B.; Peck, Robert E.

    1990-01-01

    Means and methods for enhancing the output of radiant energy from a porous radiant burner by minimizing the scattering and increasing the adsorption, and thus emission of such energy by the use of randomly dispersed ceramic fibers of sub-micron diameter in the fabrication of ceramic fiber matrix burners and for use therein.

  19. Smoothing the output from a DAC

    NASA Technical Reports Server (NTRS)

    Wagner, C.

    1980-01-01

    Circuit smooths stepped waveform from analog-to-digital converter without appreciable phase shift between stepped input signal and smoothed output signal and without any effect from stepping rate. Waveform produced is suitable for driving controls used in manufacturing processes, aerospace systems, and automobiles.

  20. Solar cell system having alternating current output

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr. (Inventor)

    1980-01-01

    A monolithic multijunction solar cell was modified by fabricating an integrated circuit inverter on the back of the cell to produce a device capable of generating an alternating current output. In another embodiment, integrated curcuit power conditioning electronics was incorporated in a module containing a solar cell power supply.

  1. Research Output, Socialization, and the Biglan Model.

    ERIC Educational Resources Information Center

    Creswell, John W.; Bean, John P.

    1981-01-01

    A test of the Biglan model of faculty subcultures using measures of research output and tests of the model controlling for the effects of faculty socialization are described. The Biglan model is found to be valid, and the distinctiveness of the Biglan groups appears to increase with the socialization of faculty into subject areas. (Author/MLW)

  2. Input-output, expandable-parity network

    NASA Technical Reports Server (NTRS)

    Mckevitt, J. F., III

    1974-01-01

    Large-scale integrated circuit generates and checks parity of four eight-bit registers. In addition, circuit will indicate by output signal whether parity error exists. Circuit can also generate or check parity of words up to 32 bits. This is done by making appropriate internal wiring connections on the large-scale integrated chip.

  3. On the output of acoustical sources

    NASA Technical Reports Server (NTRS)

    Levine, H.

    1979-01-01

    Contents: (1) a theoretical basis for local power calculation; (2) source radiation in the presence of a half-plane; (3) radiation from a line source near an edge at which a Kutta condition holds; (4) radiation by a point source above a plane independence boundary; and (5) power output of a point source in a uniform flow.

  4. Multiple output timing and trigger generator

    SciTech Connect

    Wheat, Robert M.; Dale, Gregory E

    2009-01-01

    In support of the development of a multiple stage pulse modulator at the Los Alamos National Laboratory, we have developed a first generation, multiple output timing and trigger generator. Exploiting Commercial Off The Shelf (COTS) Micro Controller Units (MCU's), the timing and trigger generator provides 32 independent outputs with a timing resolution of about 500 ns. The timing and trigger generator system is comprised of two MCU boards and a single PC. One of the MCU boards performs the functions of the timing and signal generation (the timing controller) while the second MCU board accepts commands from the PC and provides the timing instructions to the timing controller. The PC provides the user interface for adjusting the on and off timing for each of the output signals. This system provides 32 output or timing signals which can be pre-programmed to be in an on or off state for each of 64 time steps. The width or duration of each of the 64 time steps is programmable from 2 {micro}s to 2.5 ms with a minimum time resolution of 500 ns. The repetition rate of the programmed pulse train is only limited by the time duration of the programmed event. This paper describes the design and function of the timing and trigger generator system and software including test results and measurements.

  5. 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.

  6. 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.

  7. Different Styles of Hearing Aids

    MedlinePlus

    ... aids available and offer some cosmetic and listening advantages. Photo courtesy of Phonak Click for larger image ... in place. These aids offer cosmetic and listening advantages and are used typically for adults. Photo courtesy ...

  8. Basic HIV/AIDS Statistics

    MedlinePlus

    ... Other regions significantly affected by HIV/AIDS include Asia and the Pacific, Latin America and the Caribbean, and Eastern Europe and Central Asia. CDC’s Global AIDS website explains what CDC is ...

  9. American Foundation for AIDS Research

    MedlinePlus

    ... More To the Ends of the Earth for AIDS Research Swedish explorer Johan Ernst Nilson has raised ... More amfAR-Funded HIV Scholars Program Featured in AIDS and Behavior Supplement amfAR has partnered with the ...

  10. 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.

  11. 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.

  12. Living with AIDS: Part II.

    ERIC Educational Resources Information Center

    Daedalus: Journal of the American Academy of Arts and Sciences, 1989

    1989-01-01

    A series of articles concerning various aspects of AIDS and the dilemmas it poses for U.S. society, culture, and government are presented, in this theme issue, e.g., "Introduction to the Issue" (K. Keniston); "Prospects for the Medical Control of the AIDS Epidemic" (W. Haseltine); "Social Policy: AIDS and Intravenous Drug Use" (N. Zinberg);…

  13. Manual for Student Financial Aids.

    ERIC Educational Resources Information Center

    MacDonald, Douglas S.

    This manual was designed to provide structural guidelines for financial aid program operations and administration at the Community College of Baltimore. Topics discussed include: the philosophy of student aid at an open door college; the objectives of the student financial aid office; staff development and administrative improvement; organization,…

  14. Teachers' Aides: Tasks and Concerns

    ERIC Educational Resources Information Center

    Balderson, James H.; Nixon, Mary

    1976-01-01

    Addresses three questions: (1) What tasks do aides perform? (2) Does training make a difference in the type of tasks aides perform? (3) What are the concerns of aides? (Available from the Department of Educational Administration, The University of Alberta, Edmonton, Alberta, Canada T6G 2G5; $0.50, single copy.) (Author/IRT)

  15. Pharmacotherapeutics for the AIDS Patient.

    ERIC Educational Resources Information Center

    Fife, Kenneth H.

    1991-01-01

    Anticipated shifts in the demographics of the Acquired Immune Deficiency Syndrome (AIDS) epidemic are examined, current state-of-the-art AIDS patient management is summarized, and some unique facets of drug therapy in the AIDS patient are discussed, including adverse reactions, complex drug interactions, use of investigational drugs, and…

  16. How Do People Get AIDS?

    MedlinePlus

    ... of Healthy Breakfasts Shyness How Do People Get AIDS? KidsHealth > For Teens > How Do People Get AIDS? Print A A A en español ¿Cómo contrae alguien el SIDA? AIDS stands for acquired immunodeficiency syndrome , a disease that ...

  17. Jet and ultrasonic nebuliser output: use of a new method for direct measurement of aerosol output.

    PubMed Central

    Dennis, J H; Stenton, S C; Beach, J R; Avery, A J; Walters, E H; Hendrick, D J

    1990-01-01

    Output from jet nebulisers is calibrated traditionally by weighing them before and after nebulisation, but the assumption that the weight difference is a close measure of aerosol generation could be invalidated by the concomitant process of evaporation. A method has been developed for measuring aerosol output directly by using a solute (fluoride) tracer and aerosol impaction, and this has been compared with the traditional weight loss method for two Wright, six Turbo, and four Micro-Cirrus jet nebulisers and two Microinhaler ultrasonic nebulisers. The weight loss method overestimated true aerosol output for all jet nebulisers. The mean aerosol content, expressed as a percentage of the total weight loss, varied from as little as 15% for the Wright jet nebulisers to 54% (range 45-61%) for the Turbo and Micro-Cirrus jet nebulisers under the operating conditions used. In contrast, there was no discrepancy between weight loss and aerosol output for the ultrasonic nebulisers. These findings, along with evidence of both concentrating and cooling effects from jet nebulisation, confirm that total output from jet nebulisers contains two distinct fractions, vapour and aerosol. The vapour fraction, but not the aerosol fraction, was greatly influenced by reservoir temperature within the nebuliser; so the ratio of aerosol output to total weight loss varied considerably with temperature. It is concluded that weight loss is an inappropriate method of calibrating jet nebuliser aerosol output, and that this should be measured directly. PMID:2247862

  18. Computer aided manipulator control

    NASA Technical Reports Server (NTRS)

    Bejczy, A. K.; Zawacki, R. L.

    1980-01-01

    This paper describes the hardware and software system of a dedicated mini- and microcomputer network developed at the JPL teleoperator project to aid the operator in real-time control of remote manipulators. The operator can be in series or in parallel with the control computer during operation. The purpose of the project is to develop, demonstrate and evaluate advanced supervisory control concepts and techniques for space applications. The paper concludes with a brief outline of future development plans and issues.

  19. Directional Hearing Aid

    NASA Technical Reports Server (NTRS)

    Jhabvala, M.; Lin, H. C.

    1989-01-01

    Hearing-aid device indicates visually whether sound is coming from left, right, back, or front. Device intended to assist individuals who are deaf in at least one ear and unable to discern naturally directions to sources of sound. Device promotes safety in street traffic, on loading docks, and in presence of sirens, alarms, and other warning sounds. Quadraphonic version of device built into pair of eyeglasses and binaural version built into visor.

  20. The pathology of AIDS.

    PubMed Central

    Macher, A M

    1988-01-01

    The acquired immunodeficiency syndrome (AIDS) is a devastating new disease caused by the human immunodeficiency virus (HIV). This retrovirus causes profound immunoincompetence in its infected hosts, who are thereafter susceptible to develop myriad severe and relapsing protozoal, fungal, bacterial, viral, and arthropodal opportunistic infections, as well as unusual malignancies. The more than 50,000 patients who have developed AIDS in the United States have produced a sudden unexpected deluge of diagnostic dilemmas that are stressing laboratories of pathology everywhere. This paper describes the gross and microscopic pathology of the numerous complications in patients infected by HIV: (a) the prodromal AIDS-related complex with persistent generalized lymphadenopathy, (b) lymphoid infiltration of salivary gland and lung, including the complex of lymphoid interstitial pneumonitis-pulmonary lymphoid hyperplasia, (c) extranodal non-Hodgkin's lymphomas, (d) multifocal mucocutaneous and visceral Kaposi's sarcoma, (e) small cell undifferentiated (oat cell) carcinomas, (f) protozoal infections caused by Pneumocystis carinii, Toxoplasma gondii, Acanthamoeba, Cryptosporidium species (sp.), and Isospora belli, (g) the causes of chronic enteritis, (h) mycotic infections caused by Candida sp., Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, and Sporothrix schenckii, (i) bacterial infections caused by Mycobacterium avium-intracellulare, M. tuberculosis, M. kansasii, Nocardia sp., Listeria monocytogenes, Legionella sp., Treponema pallidum, and others, (j) viral infections caused by cytomegalovirus, herpes simplex and zoster, polyomavirus (progressive multifocal leukoencephalopathy), hepatitis B, molluscum contagiosum, and papillomavirus, (k) oral hairy leukoplakia, (l) subacute encephalopathy, and (m) Norwegian scabies. PMID:2836878

  1. Migrants and HIV / AIDS.

    PubMed

    Duckett, M

    2000-06-01

    This paper outlines some of the imperatives that should drive attention to the rights of legal and illegal migrants to health, particularly in relation to HIV/AIDS. It is noted that migrants can be especially vulnerable to HIV/AIDS/sexually transmitted diseases (STDs), but they are often excluded or simply missed in many prevention and care programs. In terms of the effects of globalization, it would seem that governments are required to ensure that this state of affairs does not continue. Evidence indicates that human rights and other ethical violations are occurring and need to be urgently addressed at local, national and international levels. In view of such, it is recommended that HIV/AIDS/STD prevention and care programs for migrant populations should be developed with and guided by migrant communities, and involving substantial community mobilization. Although some progress in preventing the spread of HIV to and from migrants have been documented, and projects addressing their needs have been made accessible, the challenge of dealing more comprehensively the complex issues involved still remains.

  2. Channel capacity and receiver deployment optimization for multi-input multi-output visible light communications.

    PubMed

    Wang, Jin-Yuan; Dai, Jianxin; Guan, Rui; Jia, Linqiong; Wang, Yongjin; Chen, Ming

    2016-06-13

    Multi-input multi-output (MIMO) technique is attractive for visible light communication (VLC), which exploits the high signal-to-noise ratio (SNR) of a single channel to overcome the capacity limitation due to the small modulation bandwidth of the light emitting diode. This paper establishes a MIMO VLC system under the non-negativity, peak power and dimmable average power constraints. Assume that perfect channel state information at the transmitter is known, the MIMO channel is changed to parallel, non-interfering sub-channels by using the singular value decomposition (SVD). Based on the SVD, the lower bound on the channel capacity for MIMO VLC is derived by employing entropy power inequality and variational method. Moreover, by maximizing the derived lower bound on the capacity under the given constraints, the receiver deployment optimization problem is formulated. The problem is solved by employing the principle of particle swarm optimization. Numerical results verify the derived capacity bound and the proposed deployment optimization scheme.

  3. Cooperative linear output regulation for networked systems by dynamic measurement output feedback

    NASA Astrophysics Data System (ADS)

    Li, Shaobao; Feng, Gang; Wang, Juan; Luo, Xiaoyuan; Guan, Xinping

    2016-04-01

    This paper investigates the cooperative linear output regulation problem of a class of heterogeneous networked systems with a common reference input but with different disturbances for individual nodes. A novel distributed control law is presented based on dynamic measurement output feedback. It is shown that the overall networked closed-loop control system is asymptotically stable and the output regulation errors asymptotically approach zero as time goes to infinity under a sufficient and necessary condition. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed control law.

  4. Comparison of SNR and CNR for in vivo mouse brain imaging at 3 and 7 T using well matched scanner configurations.

    PubMed

    DiFrancesco, M W; Rasmussen, J M; Yuan, W; Pratt, R; Dunn, S; Dardzinski, B J; Holland, S K

    2008-09-01

    Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for magnetic resonance microimaging were measured using two nearly identical magnetic resonance imaging (MRI) scanners operating at field strengths of 3 and 7 T. Six mice were scanned using two imaging protocols commonly applied for in vivo imaging of small animal brain: RARE and FLASH. An accounting was made of the field dependence of relaxation times as well as a small number of hardware disparities between scanner systems. Standard methods for relaxometry were utilized to measure T1 and T2 for two white matter (WM) and two gray matter (GM) regions in the mouse brain. An average increase in T1 between 3 and 7 T of 28% was observed in the brain. T2 was found to decrease by 27% at 7 T in agreement with theoretical models. The SNR was found to be uniform throughout the mouse brain, increasing at higher field by a factor statistically indistinguishable from the ratio of Larmor frequencies when imaging with either method. The CNR between GM and WM structures was found to adhere to the expected field dependence for the RARE imaging sequence. Improvement in the CNR for the FLASH imaging sequence between 3 and 7 T was observed to be greater than the Larmor ratio, reflecting a greater susceptibility to partial volume effects at the lower SNR values at 3 T. Imaging at 7 T versus 3 T in small animals clearly provides advantages with respect to the CNR, even beyond the Larmor ratio, especially in lower SNR regimes. This careful multifaceted assessment of the benefits of higher static field is instructive for those newly embarking on small animal imaging. Currently the number of 7 T MRI scanners in use for research in human subjects is increasing at a rapid pace with approximately 30 systems deployed worldwide in 2008. The data presented in this article verify that if system performance and radio frequency uniformity is optimized at 7 T, it should be possible to realize the expected improvements in the CNR and SNR

  5. Spacelab output processing system architectural study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Two different system architectures are presented. The two architectures are derived from two different data flows within the Spacelab Output Processing System. The major differences between these system architectures are in the position of the decommutation function (the first architecture performs decommutation in the latter half of the system and the second architecture performs that function in the front end of the system). In order to be examined, the system was divided into five stand-alone subsystems; Work Assembler, Mass Storage System, Output Processor, Peripheral Pool, and Resource Monitor. The work load of each subsystem was estimated independent of the specific devices to be used. The candidate devices were surveyed from a wide sampling of off-the-shelf devices. Analytical expressions were developed to quantify the projected workload in conjunction with typical devices which would adequately handle the subsystem tasks. All of the study efforts were then directed toward preparing performance and cost curves for each architecture subsystem.

  6. Cardiac output determinations with ear piece densitometry.

    PubMed

    Hedenstierna, G; Schildt, B

    1975-01-01

    The results of cardiac output determinations by a dye dilution technique were compared using (a) a dichromatic earpiece which was calibrated as a flow-through cuvette, but also permitted automatic computing by virtue of a pressure capsule, and (b) an ordinary flow-through densitometer. Eleven subjects, some with cardio-pulmonary disease, were investigated. Cardiac outputs were systematically overestimated when automatically computed. The results obtained by manual calculation with the ear-piece corresponded more nearly with those derived from the flow-through cuvette, but still with a deviation from the identity line and with a residual standard deviation of 0.8 l/min. Double determinations had a residual standard deviation of 0.7 l/min. Despite its ease of handling, an earpiece densitometer seems to be too unreliable to be suitable for routine use.

  7. Characterizing output bottlenecks in a supercomputer

    SciTech Connect

    Xie, Bing; Chase, Jeffrey; Dillow, David A; Drokin, Oleg; Klasky, Scott A; Oral, H Sarp; Podhorszki, Norbert

    2012-01-01

    Supercomputer I/O loads are often dominated by writes. HPC (High Performance Computing) file systems are designed to absorb these bursty outputs at high bandwidth through massive parallelism. However, the delivered write bandwidth often falls well below the peak. This paper characterizes the data absorption behavior of a center-wide shared Lustre parallel file system on the Jaguar supercomputer. We use a statistical methodology to address the challenges of accurately measuring a shared machine under production load and to obtain the distribution of bandwidth across samples of compute nodes, storage targets, and time intervals. We observe and quantify limitations from competing traffic, contention on storage servers and I/O routers, concurrency limitations in the client compute node operating systems, and the impact of variance (stragglers) on coupled output such as striping. We then examine the implications of our results for application performance and the design of I/O middleware systems on shared supercomputers.

  8. Financial Aid Administrators' Views on Simplifying Financial Aid: NASFAA's 2008 Financial Aid Simplification Survey Report

    ERIC Educational Resources Information Center

    National Association of Student Financial Aid Administrators (NJ1), 2008

    2008-01-01

    Despite a decade of simplification efforts, students and families are often still baffled by the student aid process and cringe at the sight of financial aid application forms. Contrary to its purpose of helping students to access college, the student aid application process causes families frustration and confusion that has been cited as an…

  9. Generalized Input-Output Inequality Systems

    SciTech Connect

    Liu Yingfan Zhang Qinghong

    2006-09-15

    In this paper two types of generalized Leontief input-output inequality systems are introduced. The minimax properties for a class of functions associated with the inequalities are studied. Sufficient and necessary conditions for the inequality systems to have solutions are obtained in terms of the minimax value. Stability analysis for the solution set is provided in terms of upper semi-continuity and hemi-continuity of set-valued maps.

  10. Finite Element Output Bounds for Hyperbolic Problems

    SciTech Connect

    Machiels, L.

    2000-03-27

    We propose a Neumann-subproblem a posteriori finite element error bound technique for linear stationary scalar advection problems. The method is similar in many respects to the previous output bound technique developed for elliptic problems. In the new approach, however, the primal residual is enhanced with a streamline diffusion term. We first formulate the bound algorithm, with particular emphasis on the proof of the bounding properties; then, we provide numerical results for an illustrative example.

  11. Dual-Sampler Processor Digitizes CCD Output

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.

    1986-01-01

    Circuit for processing output of charge-coupled device (CCD) imager provides increased time for analog-to-digital conversion, thereby reducing bandwidth required for video processing. Instead of one sampleand-hold circuit of conventional processor, improved processor includes two sample-and-hold circuits alternated with each other. Dual-sampler processor operates with lower bandwidth and with timing requirements less stringent than those of single-sample processor.

  12. Listening to music affects diurnal variation in muscle power output.

    PubMed

    Chtourou, H; Chaouachi, A; Hammouda, O; Chamari, K; Souissi, N

    2012-01-01

    The purpose of this investigation was to assess the effects of listening to music while warming-up on the diurnal variations of power output during the Wingate test. 12 physical education students underwent four Wingate tests at 07:00 and 17:00 h, after 10 min of warm-up with and without listening to music. The warm-up consisted of 10 min of pedalling at a constant pace of 60 rpm against a light load of 1 kg. During the Wingate test, peak and mean power were measured. The main finding was that peak and mean power improved from morning to afternoon after no music warm-up (p<0.001 and p<0.01, respectively). These diurnal variations disappeared for mean power and persisted with an attenuated morning-evening difference (p<0.05) for peak power after music warm-up. Moreover, peak and mean power were significantly higher after music than no music warm-up during the two times of testing. Thus, as it is a legal method and an additional aid, music should be used during warm-up before performing activities requiring powerful lower limbs' muscles contractions, especially in the morning competitive events.

  13. Nonverbal perceptual organization output disability and schizophrenia spectrum symptomatology.

    PubMed

    Silverstein, S M; Palumbo, D R

    1995-02-01

    Patients with neurodevelopmental syndromes often receive numerous psychiatric diagnoses before the true nature of their disorder becomes apparent. We present a case in which the neuropsychological evaluation played a significant role in reconceptualizing a patient who had received, at various times, diagnoses of schizotypal personality disorder, schizoaffective disorder, and schizophrenia. The identification of specific cognitive deficits in executive functioning, perceptual organization, visual-spatial problem solving, and abstraction led to: 1) a diagnosis of nonverbal perceptual-organization-output disabled; 2) the adoption of a rehabilitative treatment model; and 3) a greater understanding of the way in which the patient's social deficits represented adaptations to her cognitive impairments. Research data and theoretical models relating cognitive deficits to psychiatric symptoms are discussed, and evidence is presented that schizophrenia and certain neurodevelopmental syndromes may share commonalities of pathophysiology. Diagnostic issues arising from similarities between these disorders are discussed. It is suggested that direct comparisons between these groups can aid in clarifying the specific nature of cognitive deficit-symptom relationships, as well as leading to improvements in the understanding, diagnosis and treatment of schizophrenic and neurodevelopmental syndromes.

  14. Burst Firing Enhances Neural Output Correlation

    PubMed Central

    Chan, Ho Ka; Yang, Dong-Ping; Zhou, Changsong; Nowotny, Thomas

    2016-01-01

    Neurons communicate and transmit information predominantly through spikes. Given that experimentally observed neural spike trains in a variety of brain areas can be highly correlated, it is important to investigate how neurons process correlated inputs. Most previous work in this area studied the problem of correlation transfer analytically by making significant simplifications on neural dynamics. Temporal correlation between inputs that arises from synaptic filtering, for instance, is often ignored when assuming that an input spike can at most generate one output spike. Through numerical simulations of a pair of leaky integrate-and-fire (LIF) neurons receiving correlated inputs, we demonstrate that neurons in the presence of synaptic filtering by slow synapses exhibit strong output correlations. We then show that burst firing plays a central role in enhancing output correlations, which can explain the above-mentioned observation because synaptic filtering induces bursting. The observed changes of correlations are mostly on a long time scale. Our results suggest that other features affecting the prevalence of neural burst firing in biological neurons, e.g., adaptive spiking mechanisms, may play an important role in modulating the overall level of correlations in neural networks. PMID:27242499

  15. Structured output tracking guided by keypoint matching

    NASA Astrophysics Data System (ADS)

    Fang, Zhiwen; Cao, Zhiguo; Xiao, Yang

    2016-10-01

    Current keypoint-based trackers are widely used in object tracking system because of their robust capability against scale, rotation and so on. However, when these methods are applied in tracking 3D target in a forward-looking image sequences, the tracked point usually shifts away from the correct position as time increases. In this paper, to overcome the tracked point drifting, structured output tracking is used to track the target point with its surrounding information based on Haar-like features. First, around the tracked point in the last frame, a local patch is cropped to extract Haar-like features. Second, using a structured output SVM framework, a prediction function is learned in a larger radius to directly estimate the patch transformation between frames. Finally, during tracking the prediction function is applied to search the best location in a new frame. In order to achieve the robust tracking in real time, keypoint matching is adopted to coarsely locate the searched field in the whole image before using the structured output tracking. Experimentally, we show that our algorithm is able to outperform state-of-the-art keypoint-based trackers.

  16. Characterizing detonator output using dynamic witness plates

    SciTech Connect

    Murphy, Michael John; Adrian, Ronald J

    2009-01-01

    A sub-microsecond, time-resolved micro-particle-image velocimetry (PIV) system is developed to investigate the output of explosive detonators. Detonator output is directed into a transparent solid that serves as a dynamic witness plate and instantaneous shock and material velocities are measured in a two-dimensional plane cutting through the shock wave as it propagates through the solid. For the case of unloaded initiators (e.g. exploding bridge wires, exploding foil initiators, etc.) the witness plate serves as a surrogate for the explosive material that would normally be detonated. The velocity-field measurements quantify the velocity of the shocked material and visualize the geometry of the shocked region. Furthermore, the time-evolution of the velocity-field can be measured at intervals as small as 10 ns using the PIV system. Current experimental results of unloaded exploding bridge wire output in polydimethylsiloxane (PDMS) witness plates demonstrate 20 MHz velocity-field sampling just 300 ns after initiation of the wire.

  17. Application of artificial neural networks in computer-aided diagnosis.

    PubMed

    Liu, Bei

    2015-01-01

    Computer-aided diagnosis is a diagnostic procedure in which a radiologist uses the outputs of computer analysis of medical images as a second opinion in the interpretation of medical images, either to help with lesion detection or to help determine if the lesion is benign or malignant. Artificial neural networks (ANNs) are usually employed to formulate the statistical models for computer analysis. Receiver operating characteristic curves are used to evaluate the performance of the ANN alone, as well as the diagnostic performance of radiologists who take into account the ANN output as a second opinion. In this chapter, we use mammograms to illustrate how an ANN model is trained, tested, and evaluated, and how a radiologist should use the ANN output as a second opinion in CAD.

  18. Multiple-Input Multiple-Output (MIMO) Linear Systems Extreme Inputs/Outputs

    DOE PAGES

    Smallwood, David O.

    2007-01-01

    A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the autospectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the autospectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input autospectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one willmore » result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.« less

  19. Extreme inputs/outputs for multiple input multiple output linear systems.

    SciTech Connect

    Smallwood, David Ora

    2005-09-01

    A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the auto spectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the auto spectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input auto spectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one will result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.

  20. Comparison of CAISO-run Plexos output with LLNL-run Plexos output

    SciTech Connect

    Schmidt, A; Meyers, C; Smith, S

    2011-12-20

    In this report we compare the output of the California Independent System Operator (CAISO) 33% RPS Plexos model when run on various computing systems. Specifically, we compare the output resulting from running the model on CAISO's computers (Windows) and LLNL's computers (both Windows and Linux). We conclude that the differences between the three results are negligible in the context of the entire system and likely attributed to minor differences in Plexos version numbers as well as the MIP solver used in each case.

  1. HIV infection and AIDS.

    PubMed

    Lloyd, A

    1996-09-01

    Many of the clinical features of HIV/AIDS can be ascribed to the profound immune deficiency which develops in infected patients. The destruction of the immune system by the virus results in opportunistic infection, as well as an increased risk of autoimmune disease and malignancy. In addition, disease manifestations related to the virus itself may occur. For example, during the primary illness which occurs within weeks after first exposure to HIV, clinical symptoms occur in at least 50% of cases, typically as a mononucleosis syndrome. HIV-related complications are rarely encountered in patients with preserved immunity (i.e. CD4 T-cell counts greater than 500 cells/mm3). Recurrent mucocutaneous herpes simplex (HSV), herpes zoster (VZV), oral candidiasis and oral hairy leukoplakia occur with increasing frequency as the CD4 count drops below this level. Immune thrombocytopenia (ITP) occurs in association with HIV and often presents early in the clinical course. The risk of developing opportunistic infections and malignancies typical of AIDS increases progressively as CD4 counts fall below 200 cells/mm3. The clinical manifestations of infections associated with AIDS tend to fall into well-recognized patterns of presentation, including pneumonia, dysphagia/odynophagia, diarrhoea, neurological symptoms, fever, wasting, anaemia and visual loss. The commonest pathogens include Candida albicans, Pneumocystis carinii, Mycobacterium tuberculosis, Toxoplasma gondii, Cryptococcus neoformans, Mycobacterium avium intracellulare and cytomegalovirus. Malignant disease in patients with HIV infection also occurs in a characteristic pattern. Only two tumours are prevalent: Kaposi's sarcoma, a multifocal tumour of vascular endothelium which typically involves skin and mucosal surfaces; and non-Hodgkin's lymphoma, which is typically high grade in phenotype, often arising within the central nervous system. The principles of therapy include reduction of HIV replication by antiretroviral

  2. Help: first aid issues.

    PubMed

    Granitoff, N; Whitaker, I Y; Diccini, S; Goncalves, V C; Marin, H F

    1995-01-01

    First aid is the initial and immediate care given to a victim outside the hospital environment, with the purpose of assuring life and avoiding worsening conditions until he/she receives qualified assistance. Providing immediate aid to someone requires tranquility and, above all, knowledge on what has to be done or not in each situation. In addition to being treated by health professionals, the chances that a victim will receive early treatment by others are large. However, in Brazil, access to information, and the possibility of reviewing it whenever necessary, may contribute greatly to the process of assimilation of this knowledge, in addition to exercises on simulated cases. Informatics has been shown as an extremely useful tool in the development of educational software, considering its multiplicity of resources and providing for the users: motivation for an interactive experience, an individualized teaching that takes into account his/her own rhythm and desired complexity level, besides making possible the user's capacity for solving problems through simulated situations. Considering that, the number of individuals of the population prepared to act as First Aid helpers in situations of life threatening accidents or sudden illness is still very scarce. The ever increasing use of the computer as a mean of spreading information in schools, enterprises, and even households and considering the advantages of an educational software for the users regarding storage and retrieval of information when needed, we proposed the creation of an interactive teaching software. This software is being developed using Storyboard live. The methodology is the following: literature review, selection of images, development of the program, application tests. The initial selected issues are: assessment of the victim, cardiorespiratory arrest and resuscitation, airway obstruction, wounds, and hemorrhages. After utilizing the program, the user should be able to solve hypothetical

  3. AIDS and family planning.

    PubMed

    1992-01-01

    In 1991, an HIV prevention program advisor and a research/evaluation specialist for family planning programs discussed problems that affected HIV prevention and family planning services in Haiti before and after the coup of the Aristide government. Population activities began aimlessly in 1974 and HIV prevention efforts only began in 1988. After the coup, Haitians lost their newly found hope for meaningful development. All foreign assistance ended and they did not trust the army. In fact, other than essential child survival activities, no health and family planning services operated for several weeks. The situation grew worse after the economic embargo. 3 months after the coup, the US considered adding family planning assistance. Still little movement of condom, family planning, and health supplies left Port-au-Prince for the provinces which adversely affected all health related efforts. Condoms could no longer be distributed easily either in the socially marketed or US supplied condom distribution programs. Before the coup, HIV prevention and family planning programs depended on peer educators to educate the public (this approach made these programs quite successful), but the 2 experts feared that they would not return to those roles and that these programs would need to completely rebuild. Another concern was the large scale urban-rural migration making it difficult for them to continue care. Early in the AIDS epidemic, the Haitian government was on the defensive because the US considered Haitians as a high risk group so it did little to prevent HIV transmission. After 1988, HIV prevention activities in Haiti centered on raising awareness and personalizing the epidemic. The AIDS specialist noted, however, that a major obstacle to increasing knowledge is that AIDS is just 1 of many fatal diseases in Haiti. Moreover few health professionals in Haiti have ever had public health training.

  4. Should Aid Reward Performance?

    PubMed Central

    Olken, Benjamin A.; Onishi, Junko; Wong, Susan

    2014-01-01

    We report an experiment in 3,000 villages that tested whether incentives improve aid efficacy. Villages received block grants for maternal and child health and education that incorporated relative performance incentives. Subdistricts were randomized into incentives, an otherwise identical program without incentives, or control. Incentives initially improved preventative health indicators, particularly in underdeveloped areas, and spending efficiency increased. While school enrollments improved overall, incentives had no differential impact on education, and incentive health effects diminished over time. Reductions in neonatal mortality in non-incentivized areas did not persist with incentives. We find no systematic scoring manipulation nor funding reallocation toward richer areas. PMID:25485039

  5. Migration and AIDS.

    PubMed

    Decosas, J; Kane, F; Anarfi, J K; Sodji, K D; Wagner, H U

    1995-09-23

    A successful short-term solution to transmission of AIDS in Western Africa by migrants involves provision of accessible and acceptable basic health and social services to migrants at their destination. The aim is to establish a sense of security and community, which is a health requirement. When migrants are excluded from community life or victimized as carriers of HIV infections, they will be driven by basic survival needs and dysfunctional social organization, which results in the rapid spread of HIV. Closing borders and mass deportation may not be an option. The long-term solution is population policy, environmental protection, and economic development. The focus on mapping the spread of AIDS must shift to a consideration of the migrant social conditions that make them vulnerable to AIDS. The issue of migration and AIDS will be addressed at the First European Conference on Tropical Medicine in October 1995 in Hamburg, Germany. In Uganda, HIV seroprevalence rates ranged from 5.5% among the stable population to 12.4% among internal migrants moving between villages to 16.3% among migrants from other areas. A World Bank project is operating in Western Africa, which traces seasonal male migration from the Cameroon to Liberia, Senegal to Nigeria, and from the Sahel to the coast during dry seasons. National border rules may influence the routes but not the extent of migration. A major destination place is Cote d' Ivoire, which has 25% of total population comprised of migrants from other countries and one of the highest HIV prevalence rates in Western Africa. On plantations prostitutes are brought in. Each prostitute serves about 25 workers. The pattern of sexual mixing contributes to the high HIV rates. Female migration is smaller and usually concentrated in prostitution at place of destination. Illiteracy and poverty drive women migrants into the trade. Their frequent health problems are malaria, pelvic pain, menstrual irregularity, vaginal discharge, and genital

  6. HIV/AIDS eradication.

    PubMed

    Marsden, Matthew D; Zack, Jerome A

    2013-07-15

    Antiretroviral therapy can inhibit HIV replication in patients and prevent progression to AIDS. However, it is not curative. Here we provide an overview of what antiretroviral drugs do and how the virus persists during therapy in rare reservoirs, such as latently infected CD4+ T cells. We also outline several innovative methods that are currently under development to eradicate HIV from infected individuals. These strategies include gene therapy approaches intended to create an HIV-resistant immune system, and activation/elimination approaches directed towards flushing out latent virus. This latter approach could involve the use of novel chemically synthesized analogs of natural activating agents.

  7. Epigenetic regulation of HIV, AIDS, and AIDS-related malignancies.

    PubMed

    Verma, Mukesh

    2015-01-01

    Although epigenetics is not a new field, its implications for acquired immunodeficiency syndrome (AIDS) research have not been explored fully. To develop therapeutic and preventive approaches against the human immunodeficiency virus (HIV) and AIDS, it is essential to understand the mechanisms of interaction between the virus and the host, involvement of genetic and epigenetic mechanisms, characterization of viral reservoirs, and factors influencing the latency of the virus. Both methylation of viral genes and histone modifications contribute to initiating and maintaining latency and, depending on the context, triggering viral gene repression or expression. This chapter discusses progress made at the National Institutes of Health (NIH), recommendations from the International AIDS Society Scientific Working Group on HIV Cure, and underlying epigenetic regulation. A number of epigenetic inhibitors have shown potential in treating AIDS-related malignancies. Epigenetic drugs approved by the US Food and Drug Administration and their implications for the eradication of HIV/AIDS and AIDS-related malignancies also are discussed.Past and current progress in developing treatments and understanding the molecular mechanisms of AIDS and HIV infection has greatly improved patient survival. However, increased survival has been coupled with the development of cancer at higher rates than those observed among the HIV/AIDS-negative population. During the early days of the AIDS epidemic, the most frequent AIDS-defining malignancies were Kaposi's sarcoma and non-Hodgkin lymphoma (NHL). Now, with increased survival as the result of widespread use in the developed world of highly active antiretroviral therapy (HAART), non-AIDS defining cancers (i.e., anal, skin, and lung cancers, and Hodgkin disease) are on the increase in HIV-infected populations. The current status of AIDS-related malignancies also is discussed.

  8. Study of laser output power stabilization for a deuterium cyanide laser interferometer on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Shi, N.; Gao, X.; Jie, Y. X.; Wang, E. H.

    2011-02-01

    A control system which can improve stabilization of laser power in long-term operation automatically is designed for a deuterium cyanide (DCN) far-infrared laser interferometer on the Experimental Advanced Superconducting Tokamak. It stabilizes the output power of the laser by a closed-loop control system aided by a programmable logic controller. The system has been applied to the DCN laser and it has been proven that it is effective in stabilizing the laser near the highest scope of the output power.

  9. Combining Multiple Gyroscope Outputs for Increased Accuracy

    NASA Technical Reports Server (NTRS)

    Bayard, David S.

    2003-01-01

    A proposed method of processing the outputs of multiple gyroscopes to increase the accuracy of rate (that is, angular-velocity) readings has been developed theoretically and demonstrated by computer simulation. Although the method is applicable, in principle, to any gyroscopes, it is intended especially for application to gyroscopes that are parts of microelectromechanical systems (MEMS). The method is based on the concept that the collective performance of multiple, relatively inexpensive, nominally identical devices can be better than that of one of the devices considered by itself. The method would make it possible to synthesize the readings of a single, more accurate gyroscope (a virtual gyroscope) from the outputs of a large number of microscopic gyroscopes fabricated together on a single MEMS chip. The big advantage would be that the combination of the MEMS gyroscope array and the processing circuitry needed to implement the method would be smaller, lighter in weight, and less power-hungry, relative to a conventional gyroscope of equal accuracy. The method (see figure) is one of combining and filtering the digitized outputs of multiple gyroscopes to obtain minimum-variance estimates of rate. In the combining-and-filtering operations, measurement data from the gyroscopes would be weighted and smoothed with respect to each other according to the gain matrix of a minimum- variance filter. According to Kalman-filter theory, the gain matrix of the minimum-variance filter is uniquely specified by the filter covariance, which propagates according to a matrix Riccati equation. The present method incorporates an exact analytical solution of this equation.

  10. Input and output constraints affecting irrigation development

    NASA Astrophysics Data System (ADS)

    Schramm, G.

    1981-05-01

    In many of the developing countries the expansion of irrigated agriculture is used as a major development tool for bringing about increases in agricultural output, rural economic growth and income distribution. Apart from constraints imposed by water availability, the major limitations considered to any acceleration of such programs are usually thought to be those of costs and financial resources. However, as is shown on the basis of empirical data drawn from Mexico, in reality the feasibility and effectiveness of such development programs is even more constrained by the lack of specialized physical and human factors on the input and market limitations on the output side. On the input side, the limited availability of complementary factors such as, for example, truly functioning credit systems for small-scale farmers or effective agricultural extension services impose long-term constraints on development. On the output side the limited availability, high risk, and relatively slow growth of markets for high-value crops sharply reduce the usually hoped-for and projected profitable crop mix that would warrant the frequently high costs of irrigation investments. Three conclusions are drawn: (1) Factors in limited supply have to be shadow-priced to reflect their high opportunity costs in alternative uses. (2) Re-allocation of financial resources from immediate construction of projects to longer-term increase in the supply of scarce, highly-trained manpower resources are necessary in order to optimize development over time. (3) Inclusion of high-value, high-income producing crops in the benefit-cost analysis of new projects is inappropriate if these crops could potentially be grown in already existing projects.

  11. Fuel dispenser aid

    SciTech Connect

    Bobst, J.M.

    1993-08-31

    A fuel dispenser aid is described for holding a trigger-like valve operating lever relative to a pistol grip-like handle portion of a valving device for dispensing gasoline or other fuels through a nozzle of the valving device, said fuel dispenser aid comprising: a mounting member formed of a material having a resilient, shape retaining character and configured for mounting over the pistol grip-like handle portion of the valving device, a flexible strap secured at a first end thereof to the mounting member and extending freely therefrom such that when the mounting member is mounted over the pistol grip-like handle portion of the valving device the free portion of the strap can he looped under the trigger-like valve operating lever and up to the mounting member, and fastening means for releasably and adjustably fastening the free portion of the strap to the mounting member after the free portion of the strap has been looped under the valve operating lever and up to the mounting member whereby the valve operating lever can be held in a desired set position relative to the handle portion of the valving device for dispensing fuel without requiring that the operating lever of the valving device continuously be manually held in said set position.

  12. Migration and AIDS.

    PubMed

    1998-01-01

    This article presents the perspectives of UNAIDS and the International Organization for Migration (IOM) on migration and HIV/AIDS. It identifies research and action priorities and policy issues, and describes the current situation in major regions of the world. Migration is a process. Movement is enhanced by air transport, rising international trade, deregulation of trade practices, and opening of borders. Movements are restricted by laws and statutes. Denial to freely circulate and obtain asylum is associated with vulnerability to HIV infections. A UNAIDS policy paper in 1997 and IOM policy guidelines in 1988 affirm that refugees and asylum seekers should not be targeted for special measures due to HIV/AIDS. There is an urgent need to provide primary health services for migrants, voluntary counseling and testing, and more favorable conditions. Research is needed on the role of migration in the spread of HIV, the extent of migration, availability of health services, and options for HIV prevention. Research must be action-oriented and focused on vulnerability to HIV and risk taking behavior. There is substantial mobility in West and Central Africa, economic migration in South Africa, and nonvoluntary migration in Angola. Sex workers in southeast Asia contribute to the spread. The breakup of the USSR led to population shifts. Migrants in Central America and Mexico move north to the US where HIV prevalence is higher.

  13. Nano-JASMINE: Simulation of Data Outputs

    NASA Astrophysics Data System (ADS)

    Kobayashi, Y.; Yano, T.; Hatsutori, Y.; Gouda, N.; Murooka, J.; Niwa, Y.; Yamada, Y.

    2011-02-01

    We simulated the data outputs of the first Japanese astrometry satellite Nano-JASMINE, which is scheduled to be launched by the Cyclone-4 rocket in August 2011. The simulations were carried out using existing stellar catalogues such as the Hipparcos catalogue, the Tycho catalogue, and the Guide Star catalogue version 2.3. Several statics are shown such as the number of stars those will be measured distances using annual aberration observations. The method for determining the initial direction of the satellite's spin axis has also been discussed. In this case, the frequency of bright stars observed by the satellite is an important factor.

  14. Inductive Output Tubes -- Status and Future Direction

    NASA Astrophysics Data System (ADS)

    Bohlen, Heinz

    2002-08-01

    Invented in 1938, at the same time as the klystron, it took the Inductive Output Tube (IOT) more than 40 years to surface as a useful device. Its progress after that event was rapid. Though plagued by teething problems in the beginning, it has since replaced the klystron as a TV amplifier in UHF, and it holds its own against the solid-state competition in that application. The IOT also shows much promise as a high-power amplifier, but early developments in this direction have remained solitary events so far. The paper discusses the causes and the potential of the device for future high-power applications.

  15. Output tube emission characteristics of operational radars

    NASA Astrophysics Data System (ADS)

    Matheson, R. J.; Smilley, J. D.; Falcon, G. D.; Lawrence, V. S.

    1982-01-01

    Measurement of the emission spectra and other characteristics of many radars operating in the government frequency bands is described. The emission spectra of 19 different types of radars, selected to show the different emission spectrum characteristics produced by a variety of radar output tube technologies are presented. The radars include examples of ground based search, airport surveillance, weather, and height finding radars operating in L band, S band, or C band. The RSMS, contained within a mobile van, is described, along with the measurement techniques used for obtaining radar emission characteristics. The emission limits imposed by the Radar Spectrum Engineering Criteria (RSEC) are displayed with each emission spectrum.

  16. Off-set stabilizer for comparator output

    DOEpatents

    Lunsford, James S.

    1991-01-01

    A stabilized off-set voltage is input as the reference voltage to a comparator. In application to a time-interval meter, the comparator output generates a timing interval which is independent of drift in the initial voltage across the timing capacitor. A precision resistor and operational amplifier charge a capacitor to a voltage which is precisely offset from the initial voltage. The capacitance of the reference capacitor is selected so that substantially no voltage drop is obtained in the reference voltage applied to the comparator during the interval to be measured.

  17. HCN laser with an adaptive output mirror

    SciTech Connect

    Kamenev, Yu E; Masalov, S A; Filimonova, A A

    2006-09-30

    A device for optimal coupling between a laser resonator and the external medium, having the form of one-dimensional wire grating conjugated with a plane mirror with an aperture, is proposed, developed and tested experimentally. The dependences of the output laser power on the separation between the grating and the mirror, diameter of the aperture in the plane mirror, and the grating period, are studied. The obtained results not only confirm the possibility of using such a coupling device, but also point towards the ways and principles of its application. (lasers)

  18. Uncertainties in predicting solar panel power output

    NASA Technical Reports Server (NTRS)

    Anspaugh, B.

    1974-01-01

    The problem of calculating solar panel power output at launch and during a space mission is considered. The major sources of uncertainty and error in predicting the post launch electrical performance of the panel are considered. A general discussion of error analysis is given. Examples of uncertainty calculations are included. A general method of calculating the effect on the panel of various degrading environments is presented, with references supplied for specific methods. A technique for sizing a solar panel for a required mission power profile is developed.

  19. Depression and HIV/AIDS.

    PubMed

    Benton, Tami D

    2008-06-01

    HIV/AIDS continues to be a significant public health problem. Millions of people worldwide are infected with this virus daily, and thousands die yearly of AIDS-related illnesses. Despite rapid advances in our knowledge about HIV and its mode of transmission, we have been unable to find a cure or prevent new infections. Psychiatric comorbidity is associated with HIV/AIDS: as a risk factor for HIV infection, a comorbidity of HIV infection, sequelae of HIV/AIDS, and a potential mediator for progression to AIDS. In this article, we focus on depression, which is prevalent in HIV/AIDS. We review the evidence associating depression with HIV, the challenges in recognizing depression in HIV-positive individuals, and the psychopharmacologic strategies known to be effective in the treatment of HIV-positive individuals with depression.

  20. Frequency-Shift Hearing Aid

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.

    1994-01-01

    Proposed hearing aid maps spectrum of speech into band of lower frequencies at which ear remains sensitive. By redirecting normal speech frequencies into frequency band from 100 to 1,500 Hz, hearing aid allows people to understand normal conversation, including telephone calls. Principle operation of hearing aid adapted to other uses such as, clearing up noisy telephone or radio communication. In addition, loud-speakers more easily understood in presence of high background noise.

  1. 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.

  2. World crude output overcomes Persian Gulf disruption

    SciTech Connect

    Not Available

    1992-02-01

    Several OPEC producers made good on their promises to replace 2.7 MMbpd of oil exports that vanished from the world market after Iraq took over Kuwait. Even more incredibly, they accomplished this while a breathtaking 1.2- MMbopd reduction in Soviet output took place during the course of 1991. After Abu Dhabi, Indonesia, Iran, Libya, Nigeria, Saudi Arabia and Venezuela turned the taps wide open, their combined output rose 2.95 MMbopd. Put together with a 282,000-bopd increase by Norway and contributions from smaller producers, this enabled world oil production to remain within 400,000 bopd of its 1990 level. The 60.5-MMbopd average was off by just 0.7%. This paper reports that improvement took place in five of eight regions. Largest increases were in Western Europe and Africa. Greatest reductions occurred in Eastern Europe and the Middle East. Fifteen nations produced 1 MMbopd or more last year, compared with 17 during 1990.

  3. Public knowledge about AIDS increasing.

    PubMed

    Campbell, M J; Waters, W E

    1987-04-04

    In response to concern over the perceived limited effectiveness of Department of Health and Social Security (UK) advertising campaigns to inform the public of the basic facts of Acquired Immunodeficiency Syndrome (AIDS), a prospective questionnaire study was undertaken in Southampton, England to test the effectiveness of government education prior to a January, 1987 government television/leaflet advertising campaign. 300 questionnaires about AIDS were mailed in December of 1986 to a sample drawn from electoral rolls. The response rate was 61%. Most of the questions were drawn from material covered in the campaign. The results seemed to indicate a small overall increase in knowledge about AIDS. Some changes from a June survey were noted, e.g.: more people were aware that AIDS is a virus for which there is no cure and that it is not readily transmitted by sharing washing, eating or drinking utensils; more people believed that the statement that women are at greater risk for catching AIDS is false. Respondents were generally favorable to the government's continued use of television, even with explicit language, and to its use of the schools, for AIDS education. Many were not aware of the dangers to intravenous drug users or of the symptoms of AIDS. Other surveys have shown an increasing knowledge of AIDS dangers. It is possible that television coverage of the problem will continue to be necessary, in order that less literate populations be reached. Further AIDS health education in general is needed.

  4. A code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check codes

    NASA Astrophysics Data System (ADS)

    Bai, Cheng-lin; Cheng, Zhi-hui

    2016-09-01

    In order to further improve the carrier synchronization estimation range and accuracy at low signal-to-noise ratio ( SNR), this paper proposes a code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check (NB-LDPC) codes to study the polarization-division-multiplexing coherent optical orthogonal frequency division multiplexing (PDM-CO-OFDM) system performance in the cases of quadrature phase shift keying (QPSK) and 16 quadrature amplitude modulation (16-QAM) modes. The simulation results indicate that this algorithm can enlarge frequency and phase offset estimation ranges and enhance accuracy of the system greatly, and the bit error rate ( BER) performance of the system is improved effectively compared with that of the system employing traditional NB-LDPC code-aided carrier synchronization algorithm.

  5. Electronic filters, signal conversion apparatus, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

    1994-01-01

    An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

  6. Aids and Infectious Diseases (aid) Pmp 2013 Report

    NASA Astrophysics Data System (ADS)

    Buonaguro, Franco M.

    2014-07-01

    The AIDS and Infectious Diseases (AID) PMP of the WFS contributed this year with a session on August 22nd to the Plenary Sessions of the International Seminars on Planetary Emergencies and Associated Meetings--46th Session: The Role of Science in the Third Millennium (Erice, 19-24 August 2013). Furthermore a workshop on August 24th was organized...

  7. Psychological First Aid

    PubMed Central

    Shultz, James M; Forbes, David

    2014-01-01

    Psychological first aid (PFA) has become the flagship early intervention for disaster survivors, with recent adaptations for disaster responders, in the post-9/11 era. PFA is broadly endorsed by expert consensus and integrated into guidelines for mental health and psychosocial support in disasters and extreme events. PFA frameworks are proliferating, with increasing numbers of models developed for delivery by a range of providers for use with an expanding array of target populations. Despite popularity and promotion there remains a dearth of evidence for effectiveness and recent independent reviews of PFA have highlighted this important gap. This commentary juxtaposes the current propagation of PFA against the compelling need to produce evidence for effectiveness and suggests a series of actions to prioritize and expedite real-time, real-event field evaluation of PFA.

  8. AIDS and sex tourism.

    PubMed

    Herold, E S; Van Kerkwijk, C

    1992-01-01

    Tourists traveling internationally lower their inhibitions and take greater risks than they would typically in their home cultures. Loneliness, boredom, and a sense of freedom contribute to this behavioral change. Some tourists travel internationally in search of sexual gratification. This motivation may be actively conscious or subconscious to the traveler. Billed as romantic with great natural beauty, Thailand, the Philippines, Brazil, the Dominican Republic, and Kenya are popular destinations of tourists seeking sex. The Netherlands and countries in eastern Europe are also popular. With most initial cases of HIV infection in Europe having histories of international travel, mass tourism is a major factor in the international transmission of AIDS. While abroad, tourists have sex with casual partners, sex workers, and/or other tourists. Far from all tourists, however, carry and consistently use condoms with these partners. One study found female and non white travelers to be less likely than Whites and males to carry condoms. The risk of HIV infection increases in circumstances where condoms are not readily available in the host country and/or are of poor quality. Regarding actual condom use, a study found only 34% of sex tourists from Switzerland to consistently use condoms while abroad. 28% of men in an STD clinic in Melbourne, Australia, reported consistent condom use in sexual relations while traveling in Asia; STDs were identified in 73% of men examined. The few studies of tourists suggest that a significant proportion engage in risky behavior while traveling. HIV prevalence is rapidly increasing in countries known as destinations for sex tourism. High infection rates are especially evident among teenage sex workers in Thailand. Simply documenting the prevalence of risky behavior among sex tourists will not suffice. More research is needed on travelers and AIDS with particular attention upon the motivating factors supporting persistent high-risk behavior.

  9. On source radiation. [power output computation

    NASA Technical Reports Server (NTRS)

    Levine, H.

    1980-01-01

    The power output from given sources is usually ascertained via an energy flux integral over the normal directions to a remote (farfield) surface; an alternative procedure, which utilizes an integral that specifies the direct rate of working by the source on the resultant field, is described and illustrated for both point and continuous source distributions. A comparison between the respective procedures is made in the analysis of sound radiated from a periodic dipole source whose axis rotates in a plane, on a full or partial angular range, with prescribed frequency. Thus, adopting a conventional approach, Sretenskii (1956) characterizes the rotating dipole in terms of an infinite number of stationary ones along a pair of orthogonal directions in the plane and, through the farfield representation of the latter, arrives at a series development for the instantaneous radiated power, whereas the local manner of power calculation dispenses with the equivalent infinite aggregate of sources and yields a compact analytical result.

  10. Visualizing output for a data learning algorithm

    NASA Astrophysics Data System (ADS)

    Carson, Daniel; Graham, James; Ternovskiy, Igor

    2016-05-01

    This paper details the process we went through to visualize the output for our data learning algorithm. We have been developing a hierarchical self-structuring learning algorithm based around the general principles of the LaRue model. One example of a proposed application of this algorithm would be traffic analysis, chosen because it is conceptually easy to follow and there is a significant amount of already existing data and related research material with which to work with. While we choose the tracking of vehicles for our initial approach, it is by no means the only target of our algorithm. Flexibility is the end goal, however, we still need somewhere to start. To that end, this paper details our creation of the visualization GUI for our algorithm, the features we included and the initial results we obtained from our algorithm running a few of the traffic based scenarios we designed.

  11. Developing Tsunami Warnings Based on Model Output

    NASA Astrophysics Data System (ADS)

    Allen, Stewart; Greenslade, Diana

    2010-05-01

    The Joint Australian Tsunami Warning Centre is responsible for issuing tsunami warnings for the Australian mainland and offshore territories. Warnings are currently based on model output from the T2 scenario database. When a tsunami event occurs, the closest scenario is selected from the T2 scenario database according to the seismic parameters. The values of the maximum amplitude for the scenario are assessed within coastal regions to determine the threat level. Tsunami warnings are issued according to whether the maximum amplitudes exceed pre-determined threshold values. The threshold values have been derived empirically by consideration of past events and observed coastal impacts. This presentation will describe recent developments that have been made to improve this technique, such as consideration of percentile values of the maximum amplitude.

  12. [High output stoma: detection and approach].

    PubMed

    Arenas Villafranca, Jose Javier; Abilés, Jimena; Moreno, Gloria; Tortajada Goitia, Begoña; Utrilla Navarro, Pilar; Gándara Adán, Norberto

    2014-12-01

    High output stoma is a frequent complication in patients with ileostomies that is not well identified and is not often properly addressed by clinicians. It has not been described properly, and can vary between debits of 2.000ml in 24 h to 1.500 ml in 3-5 days, according to different authors. Frequently presents both short-term and long-term negative implications for patients and is associated with readmissions. We present a review of published literature focusing in surgical resection-related factors that influence a later appearance of this complication, causes involved in its development, the need to establish a clear and objective concept of high ouput as well as the negative implications it presents. Also we develop how should we the management of these patients regarding treatment and nutritional approach.

  13. Turbulent Output-Based Anisotropic Adaptation

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Carlson, Jan-Renee

    2010-01-01

    Controlling discretization error is a remaining challenge for computational fluid dynamics simulation. Grid adaptation is applied to reduce estimated discretization error in drag or pressure integral output functions. To enable application to high O(10(exp 7)) Reynolds number turbulent flows, a hybrid approach is utilized that freezes the near-wall boundary layer grids and adapts the grid away from the no slip boundaries. The hybrid approach is not applicable to problems with under resolved initial boundary layer grids, but is a powerful technique for problems with important off-body anisotropic features. Supersonic nozzle plume, turbulent flat plate, and shock-boundary layer interaction examples are presented with comparisons to experimental measurements of pressure and velocity. Adapted grids are produced that resolve off-body features in locations that are not known a priori.

  14. Output testing of small-arms primers

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Doris, Thomas A.; Schimmel, Morry L.

    1991-01-01

    The performance of two standard primers for initiating small-caliber ammunition are compared to that of a primer for initiating aircraft escape-system components. Three testing methods are employed including: (1) firing the primer to measure total energy delivered; (2) monitoring output in terms of gaseous product-mass flow rate and pressure as a function of time; and (3) firing the primer onto ignition material to study gas pressure produced during ignition and burning as a function of time. The results of the test demonstrate differences in the ignitability factors of the standard primers and time peak pressures of less than 100 microseconds. One unexpected result is that two percussion primers (the FA-41 and the M42C1) developed for different applications have the same ignitability. The ignitability test method is shown to yield the most useful data and can be used to specify percussion primers and optimize their performance.

  15. Handling Input and Output for COAMPS

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Patrick; Tran, Nam; Li, Yongzuo; Anantharaj, Valentine

    2007-01-01

    Two suites of software have been developed to handle the input and output of the Coupled Ocean Atmosphere Prediction System (COAMPS), which is a regional atmospheric model developed by the Navy for simulating and predicting weather. Typically, the initial and boundary conditions for COAMPS are provided by a flat-file representation of the Navy s global model. Additional algorithms are needed for running the COAMPS software using global models. One of the present suites satisfies this need for running COAMPS using the Global Forecast System (GFS) model of the National Oceanic and Atmospheric Administration. The first step in running COAMPS downloading of GFS data from an Internet file-transfer-protocol (FTP) server computer of the National Centers for Environmental Prediction (NCEP) is performed by one of the programs (SSC-00273) in this suite. The GFS data, which are in gridded binary (GRIB) format, are then changed to a COAMPS-compatible format by another program in the suite (SSC-00278). Once a forecast is complete, still another program in the suite (SSC-00274) sends the output data to a different server computer. The second suite of software (SSC- 00275) addresses the need to ingest up-to-date land-use-and-land-cover (LULC) data into COAMPS for use in specifying typical climatological values of such surface parameters as albedo, aerodynamic roughness, and ground wetness. This suite includes (1) a program to process LULC data derived from observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard NASA s Terra and Aqua satellites, (2) programs to derive new climatological parameters for the 17-land-use-category MODIS data; and (3) a modified version of a FORTRAN subroutine to be used by COAMPS. The MODIS data files are processed to reformat them into a compressed American Standard Code for Information Interchange (ASCII) format used by COAMPS for efficient processing.

  16. Translation: Aids, Robots, and Automation.

    ERIC Educational Resources Information Center

    Andreyewsky, Alexander

    1981-01-01

    Examines electronic aids to translation both as ways to automate it and as an approach to solve problems resulting from shortage of qualified translators. Describes the limitations of robotic MT (Machine Translation) systems, viewing MAT (Machine-Aided Translation) as the only practical solution and the best vehicle for further automation. (MES)

  17. Revisiting the Archival Finding Aid

    ERIC Educational Resources Information Center

    Cox, Richard J.

    2007-01-01

    Archivists have been creating finding aids for generations, and in the last three decades they have done this work via a succession of standardized formats. However, like many other disciplines, they have carried out such work in violation of systems analysis. Although purporting to have the users of finding aids systems first and foremost in…

  18. Aids and the nervous system

    SciTech Connect

    Rosenblum, M.L. ); Levy, R.M. ); Bredesen, D.E. )

    1988-01-01

    This book contains 19 chapters. Some of the titles are: Neuroradiology of acquired immunodeficiency syndrome; The AIDS dementia complex; primary infection with human immunodeficiency virus; The biology of the human immunodeficiency virus and its role in neurological disease; and Algorithms for the treatment of AIDS patients with neurological disease.

  19. Certification of Financial Aid Administrators

    ERIC Educational Resources Information Center

    Peterson, Stacey A.

    2011-01-01

    The certification of financial aid administrators has been debated for over 37 years. A job satisfaction survey conducted by the National Association of Student Financial Aid Administrators (NASFAA, 2008a) revealed that college and university administrators' perceptions of the efficiency, effectiveness, and quality of the services provided by the…

  20. Nursing Aides, Orderlies, and Attendants

    MedlinePlus

    ... therapists. See How to Become One $54,520 Personal Care Aides Personal care aides help clients with self-care and everyday tasks. They also provide social supports and assistance that enable clients to participate in ... tab describes the typical duties and responsibilities of workers in the occupation, including what tools ...