Science.gov

Sample records for count rate performance

  1. Count rate performance of a silicon-strip detector for photon-counting spectral CT

    NASA Astrophysics Data System (ADS)

    Liu, X.; Grönberg, F.; Sjölin, M.; Karlsson, S.; Danielsson, M.

    2016-08-01

    A silicon-strip detector is developed for spectral computed tomography. The detector operates in photon-counting mode and allows pulse-height discrimination with 8 adjustable energy bins. In this work, we evaluate the count-rate performance of the detector in a clinical CT environment. The output counts of the detector are measured for x-ray tube currents up to 500 mA at 120 kV tube voltage, which produces a maximum photon flux of 485 Mphotons/s/mm2 for the unattenuated beam. The corresponding maximum count-rate loss of the detector is around 30% and there are no saturation effects. A near linear relationship between the input and output count rates can be observed up to 90 Mcps/mm2, at which point only 3% of the input counts are lost. This means that the loss in the diagnostically relevant count-rate region is negligible. A semi-nonparalyzable dead-time model is used to describe the count-rate performance of the detector, which shows a good agreement with the measured data. The nonparalyzable dead time τn for 150 evaluated detector elements is estimated to be 20.2±5.2 ns.

  2. Monte Carlo simulation of intrinsic count rate performance of a scintillation camera for diagnostic images.

    PubMed

    Mowlavi, Ali Asghar; de Denaro, Mario; Fornasier, Maria Rosa; Binesh, Alireza

    2006-03-01

    This paper describes Monte Carlo simulation of intrinsic count rate performance of a scintillation gamma camera. MCNP Monte Carlo code was employed to calculate pulse height spectrum and detector efficiency. A custom code written in Fortran language was then developed to simulate, by Monte Carlo method, the distortion in pulse height spectrum due to the pile-up effect for paralyzable and nonparalyzable systems. The results of the simulations, compared with the experimental measurement of count rate performance, showed a good agreement between the two different approaches. PMID:16343910

  3. Improvements in the energy resolution and high-count-rate performance of bismuth germanate

    SciTech Connect

    Koehler, P.E.; Wender, S.A.; Kapustinsky, J.S.

    1985-01-01

    Several methods for improving the energy resolution of bismuth germanate (BGO) have been investigated. It is shown that some of these methods resulted in a substantial improvement in the energy resolution. In addition, a method to improve the performance of BGO at high counting rates has been systematically studied. The results of this study are presented and discussed.

  4. Energy resolution and high count rate performance of superconducting tunnel junction x-ray spectrometers

    SciTech Connect

    Frank, M.; Hiller, L.J.; le Grand, J.B.; Mears, C.A.; Labov, S.E.; Lindeman, M.A.; Netel, H.; Chow, D.; Barfknecht, A.

    1998-01-01

    We present experimental results obtained with a cryogenically cooled, high-resolution x-ray spectrometer based on a 141{mu}m{times}141{mu}m Nb-Al-Al{sub 2}O{sub 3}-Al-Nb superconducting tunnel junction (STJ) detector in a demonstration experiment. Using monochromatized synchrotron radiation we studied the energy resolution of this energy-dispersive spectrometer for soft x rays with energies between 70 and 700 eV and investigated its performance at count rates up to nearly 60000 cps. At count rates of several 100 cps we achieved an energy resolution of 5.9 eV (FWHM) and an electronic noise of 4.5 eV for 277 eV x rays (the energy corresponding to C K). Increasing the count rate, the resolution 277 eV remained below 10 eV for count rates up to {approximately}10000cps and then degraded to 13 eV at 23000 cps and 20 eV at 50000 cps. These results were achieved using a commercially available spectroscopy amplifier with a baseline restorer. No pile-up rejection was applied in these measurements. Our results show that STJ detectors can operate at count rates approaching those of semiconductor detectors while still providing a significantly better energy resolution for soft x rays. Thus STJ detectors may prove very useful in microanalysis, synchrotron x-ray fluorescence (XRF) applications, and XRF analysis of light elements (K lines) and transition elements (L lines). {copyright} {ital 1998 American Institute of Physics.}

  5. Performance of drift-tube detectors at high counting rates for high-luminosity LHC upgrades

    NASA Astrophysics Data System (ADS)

    Bittner, Bernhard; Dubbert, Jörg; Kortner, Oliver; Kroha, Hubert; Manfredini, Alessandro; Nowak, Sebastian; Ott, Sebastian; Richter, Robert; Schwegler, Philipp; Zanzi, Daniele; Biebel, Otmar; Hertenberger, Ralf; Ruschke, Alexander; Zibell, Andre

    2013-12-01

    The performance of pressurized drift-tube detectors at very high background rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications in large-area precision muon tracking at high-luminosity upgrades of the Large Hadron Collider (LHC). The ATLAS muon drift-tube (MDT) chambers with 30 mm tube diameter have been designed to cope with γ and neutron background hit rates of up to 500 Hz/cm2. Background rates of up to 14 kHz/cm2 are expected at LHC upgrades. The test results with standard MDT readout electronics show that the reduction of the drift-tube diameter to 15 mm, while leaving the operating parameters unchanged, vastly increases the rate capability well beyond the requirements. The development of new small-diameter muon drift-tube (sMDT) chambers for LHC upgrades is completed. Further improvements of tracking efficiency and spatial resolution at high counting rates will be achieved with upgraded readout electronics employing improved signal shaping for high counting rates.

  6. Improving the count rate performance of a modular cylindrical SPECT system

    SciTech Connect

    Li, Y.J.; Hollinger, E.F.; Liu, J.; Chang, W.

    1996-12-31

    We recently proposed a design of a modular cylindrical cardiac SPECT system. one special feature of this system is an integrated provision for transmission imaging. To meet the clinical demands of obtaining transmission images, this system must be able to achieve a very high count rate (CR). To explore methods for achieving a high CR capability on a modular cylindrical detector system, we have used our existing modular cylindrical brain SPECT system to examine the feasibility of two approaches. First, we use digital-signal-processing (DSP) boards, in parallel, to execute real time position calculations. Second, we use local encoding and triggering circuits to perform analog signal processing, including identifying the detector module and digitizing the pulse signals. The results of our preliminary investigations indicate that applying the multiple-DSP parallel position calculation and local triggering techniques in a modular SPECT system can improve the CR capability significantly. Applying local triggering increased the CR capability by 15% at a CR capability of 200 kcps. Because we have used slow-speed DSP boards during this proof-of-concept testing, we have not yet met the CR requirements for transmission imaging. However, these results indicate that by using state-of-the-art DSP boards the CR capability of this modular SPECT system can be increased to over 300 kcps.

  7. A Comparison of the High Count Rate Performance of Three Commercially Available Digital Signal Processors

    SciTech Connect

    Dawn M. Scates; John K. Hartwell

    2005-10-01

    Three commercial ã-ray digital signal processors, a Canberra InSpector 2000, an ORTEC DigiDART, and an X-ray Instrumentation Associates Polaris system, coupled to a Canberra 2002C resistive-feedback preamplifier-equipped high-purity germanium detector, were performance tested to input rates of 440 kHz. The spectrometers were evaluated on their throughput, stability and peak shape performance. The accuracy of their quantitative corrections for dead time and pile-up were also tested. All three of the tested units performed well at input rates that strain most analog spectroscopy systems.

  8. Performance evaluation of the Ingenuity TF PET/CT scanner with a focus on high count-rate conditions

    PubMed Central

    Kolthammer, Jeffrey A; Su, Kuan-Hao; Grover, Anu; Narayanan, Manoj; Jordan, David W; Muzic, Raymond F

    2015-01-01

    This study evaluated the positron emission tomography (PET) imaging performance of the Ingenuity TF 128 PET/computed tomography (CT) scanner which has a PET component that was designed to support a wider radioactivity range than is possible with those of Gemini TF PET/CT and Ingenuity TF PET/MR. Spatial resolution, sensitivity, count rate characteristics and image quality were evaluated according to the NEMA NU 2–2007 standard and ACR phantom accreditation procedures; these were supplemented by additional measurements intended to characterize the system under conditions that would be encountered during quantitative cardiac imaging with 82Rb. Image quality was evaluated using a hot spheres phantom, and various contrast recovery and noise measurements were made from replicated images. Timing and energy resolution, dead time, and the linearity of the image activity concentration, were all measured over a wide range of count rates. Spatial resolution (4.8– 5.1 mm FWHM), sensitivity (7.3 cps kBq−1), peak noise-equivalent count rate (124 kcps), and peak trues rate (365 kcps)were similar to those of the Gemini TF PET/CT. Contrast recovery was higher with a 2 mm, body-detail reconstruction than with a 4 mm, body reconstruction, although the precision was reduced. The noise equivalent count rate peak was broad (within 10% of peak from 241–609 MBq). The activity measured in phantom images was within 10% of the true activity for count rates up to those observed in 82Rb cardiac PET studies. PMID:24955921

  9. LINEAR COUNT-RATE METER

    DOEpatents

    Henry, J.J.

    1961-09-01

    A linear count-rate meter is designed to provide a highly linear output while receiving counting rates from one cycle per second to 100,000 cycles per second. Input pulses enter a linear discriminator and then are fed to a trigger circuit which produces positive pulses of uniform width and amplitude. The trigger circuit is connected to a one-shot multivibrator. The multivibrator output pulses have a selected width. Feedback means are provided for preventing transistor saturation in the multivibrator which improves the rise and decay times of the output pulses. The multivibrator is connected to a diode-switched, constant current metering circuit. A selected constant current is switched to an averaging circuit for each pulse received, and for a time determined by the received pulse width. The average output meter current is proportional to the product of the counting rate, the constant current, and the multivibrator output pulse width.

  10. Automated high performance liquid chromatography and liquid scintillation counting determination of pesticide mixture octanol/water partition rates

    SciTech Connect

    Moody, R.P.; Carroll, J.M.; Kresta, A.M.

    1987-12-01

    Two novel methods are reported for measuring octanol/water partition rates of pesticides. A liquid scintillation counting (LSC) method was developed for automated monitoring of /sup 14/C-labeled pesticides partitioning in biphasic water/octanol cocktail systems with limited success. A high performance liquid chromatography (HPLC) method was developed for automated partition rate monitoring of several constituents in a pesticide mixture, simultaneously. The mean log Kow +/- SD determined from triplicate experimental runs were for: 2,4-D-DMA (2,4-dichlorophenoxyacetic acid dimethylamine), 0.65 +/- .17; Deet (N,N-diethyl-m-toluamide), 2.02 +/- .01; Guthion (O,O-dimethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), 2.43 +/- .03; Methyl-Parathion (O,O-dimethyl-O-(p-nitrophenyl) phosphorothioate), 2.68 +/- .05; and Fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate), 3.16 +/- .03. A strong positive linear correlation (r = .9979) was obtained between log Kow and log k' (log Kow = 2.35 (log k') + 0.63). The advantages that this automated procedure has in comparison with the standard manual shake-flask procedure are discussed.

  11. Compton suppression gamma-counting: The effect of count rate

    USGS Publications Warehouse

    Millard, H.T., Jr.

    1984-01-01

    Past research has shown that anti-coincidence shielded Ge(Li) spectrometers enhanced the signal-to-background ratios for gamma-photopeaks, which are situated on high Compton backgrounds. Ordinarily, an anti- or non-coincidence spectrum (A) and a coincidence spectrum (C) are collected simultaneously with these systems. To be useful in neutron activation analysis (NAA), the fractions of the photopeak counts routed to the two spectra must be constant from sample to sample to variations must be corrected quantitatively. Most Compton suppression counting has been done at low count rate, but in NAA applications, count rates may be much higher. To operate over the wider dynamic range, the effect of count rate on the ratio of the photopeak counts in the two spectra (A/C) was studied. It was found that as the count rate increases, A/C decreases for gammas not coincident with other gammas from the same decay. For gammas coincident with other gammas, A/C increases to a maximum and then decreases. These results suggest that calibration curves are required to correct photopeak areas so quantitative data can be obtained at higher count rates. ?? 1984.

  12. Characterizing energy dependence and count rate performance of a dual scintillator fiber-optic detector for computed tomography

    SciTech Connect

    Hoerner, Matthew R. Stepusin, Elliott J.; Hyer, Daniel E.; Hintenlang, David E.

    2015-03-15

    Purpose: Kilovoltage (kV) x-rays pose a significant challenge for radiation dosimetry. In the kV energy range, even small differences in material composition can result in significant variations in the absorbed energy between soft tissue and the detector. In addition, the use of electronic systems in light detection has demonstrated measurement losses at high photon fluence rates incident to the detector. This study investigated the feasibility of using a novel dual scintillator detector and whether its response to changes in beam energy from scatter and hardening is readily quantified. The detector incorporates a tissue-equivalent plastic scintillator and a gadolinium oxysulfide scintillator, which has a higher sensitivity to scatter x-rays. Methods: The detector was constructed by coupling two scintillators: (1) small cylindrical plastic scintillator, 500 μm in diameter and 2 mm in length, and (2) 100 micron sheet of gadolinium oxysulfide 500 μm in diameter, each to a 2 m long optical fiber, which acts as a light guide to transmit scintillation photons from the sensitive element to a photomultiplier tube. Count rate linearity data were obtained from a wide range of exposure rates delivered from a radiological x-ray tube by adjusting the tube current. The data were fitted to a nonparalyzable dead time model to characterize the time response. The true counting rate was related to the reference free air dose air rate measured with a 0.6 cm{sup 3} Radcal{sup ®} thimble chamber as described in AAPM Report No. 111. Secondary electron and photon spectra were evaluated using Monte Carlo techniques to analyze ionization quenching and photon energy-absorption characteristics from free-in-air and in phantom measurements. The depth/energy dependence of the detector was characterized using a computed tomography dose index QA phantom consisting of nested adult head and body segments. The phantom provided up to 32 cm of acrylic with a compatible 0.6 cm{sup 3} calibrated

  13. Pneumotachometer counts respiration rate of human subject

    NASA Technical Reports Server (NTRS)

    Graham, O.

    1964-01-01

    To monitor breaths per minute, two rate-to-analog converters are alternately used to read and count the respiratory rate from an impedance pneumograph sequentially displayed numerically on electroluminescent matrices.

  14. Dark count rates in the STIS MAMA

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2013-06-01

    The dark count rates in the STIS MAMA detectors have been monitored. This report covers the period since the Servicing Mission 4 of May 2009. We find both long-term and short-term variations which for the NUV side we express as a function of date and temperature. The NUV dark rate has declined significantly from its surprisingly high initial rate of 0.014 counts/pixel/s that was seen immediately after SM4. By October, 2012 it had dropped to an average value of about 0.002 counts/pixel/sec The behavior and characteristics of the FUV dark rate remain very similar to that seen in 2004, prior to the STIS side-2 failure and subsequent repair.

  15. Estimating mutation rate: how to count mutations?

    PubMed Central

    Fu, Yun-Xin; Huai, Haying

    2003-01-01

    Mutation rate is an essential parameter in genetic research. Counting the number of mutant individuals provides information for a direct estimate of mutation rate. However, mutant individuals in the same family can share the same mutations due to premeiotic mutation events, so that the number of mutant individuals can be significantly larger than the number of mutation events observed. Since mutation rate is more closely related to the number of mutation events, whether one should count only independent mutation events or the number of mutants remains controversial. We show in this article that counting mutant individuals is a correct approach for estimating mutation rate, while counting only mutation events will result in underestimation. We also derived the variance of the mutation-rate estimate, which allows us to examine a number of important issues about the design of such experiments. The general strategy of such an experiment should be to sample as many families as possible and not to sample much more offspring per family than the reciprocal of the pairwise correlation coefficient within each family. To obtain a reasonably accurate estimate of mutation rate, the number of sampled families needs to be in the same or higher order of magnitude as the reciprocal of the mutation rate. PMID:12807798

  16. High Count Rate Electron Probe Microanalysis

    PubMed Central

    Geller, Joseph D.; Herrington, Charles

    2002-01-01

    Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections. This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics. Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller. PMID:27446749

  17. Clinical count rate performance of an LSO PET/CT scanner utilizing a new front-end electronics architecture with sub-nanosecond intrinsic timing resolution

    NASA Astrophysics Data System (ADS)

    Carney, J. P. J.; Townsend, D. W.

    2006-12-01

    A new front-end electronics architecture with sub-nanosecond intrinsic timing resolution has recently been incorporated into a 16 slice LSO PET/CT scanner for imaging applications in oncology. The new electronics are designed to work optimally with the lutetium orthosilicate (LSO) scintillator. Clinical performance of the LSO PET/CT is examined before and after upgrading to the new PICO 3D electronics, and compared with results using the NEMA NU 2 standard for evaluating scanner performance. Improved noise-equivalent count rates are seen in clinical studies, and reduced scatter fractions are observed, consistent with the increased lower-level energy threshold used to reject scatter events in the upgraded configuration.

  18. Shuffler bias corrections using calculated count rates

    SciTech Connect

    Rinard, Phillip M.; Hurd, J. R.; Hsue, F.

    2001-04-01

    Los Alamos National Laboratory has two identical shufflers that have been calibrated with a dozen U{sub 3}O{sub 8} certified standards from 10 g {sup 235}U to 3600 g {sup 235}U. The shufflers are used to assay a wide variety of material types for their {sup 235}U contents. When the items differ greatly in chemical composition or shape from the U{sub 3}O{sub 8} standards a bias is introduced because the calibration is not appropriate. Recently a new tool has been created to calculate shuffler count rates accurately, and this has been applied to generate bias correction factors. The tool has also been used to verify the masses and count rates of some uncertified U{sub 3}O{sub 8} standards up to 8.0 kg of {sup 235}U which were used to provisionally extend the calibration beyond the 3.6 kg of {sup 235}U mass when a special need arose. Metallic uranium has significantly different neutronic properties from the U{sub 3}O{sub 8} standards and measured count rates from metals are biased low when the U{sub 3}O{sub 8} calibration is applied. The application of the calculational tool to generate bias corrrections for assorted metals will be described. The accuracy of the calculational tool was verified using highly enriched metal disk standards that could be stacked to form cylinders or put into spread arrays.

  19. Count-Rate Statistics for Drift Detectors

    PubMed Central

    Pietraski, Philip J.; Furenlid, Lars R.

    2015-01-01

    Synchrotron light sources are low-duty-cycle pulsed X-ray sources, a fact that is often neglected in estimating the count-rate capabilities of photon-counting detectors in synchrotron-based experiments. In this paper, we demonstrate the effect that this has on the pileup statistics of drift detectors. We derive expressions for the cases of continuous and pulsed X-ray sources. We consider a pulsed source with period that is either much less than the shaper support time or much less than the average drift time. We also consider a pulsed source with a period that is long or comparable to both the shaper support and the drift time. These conditions correspond to normal and reduced bunch fill patterns of synchrotrons. PMID:27103751

  20. Who's Counted? Who's Counting? Understanding High School Graduation Rates

    ERIC Educational Resources Information Center

    Pinkus, Lyndsay

    2006-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended and funded to do: enroll, engage, and educate youth to be productive members of society. Graduation rates are not just a "bottom line" for schools--they are critical predictors of individual achievement and have undeniable…

  1. Opcode counting for performance measurement

    DOEpatents

    Gara, Alan; Satterfield, David L.; Walkup, Robert E.

    2015-08-11

    Methods, systems and computer program products are disclosed for measuring a performance of a program running on a processing unit of a processing system. In one embodiment, the method comprises informing a logic unit of each instruction in the program that is executed by the processing unit, assigning a weight to each instruction, assigning the instructions to a plurality of groups, and analyzing the plurality of groups to measure one or more metrics. In one embodiment, each instruction includes an operating code portion, and the assigning includes assigning the instructions to the groups based on the operating code portions of the instructions. In an embodiment, each type of instruction is assigned to a respective one of the plurality of groups. These groups may be combined into a plurality of sets of the groups.

  2. Opcode counting for performance measurement

    DOEpatents

    Gara, Alan; Satterfield, David L; Walkup, Robert E

    2013-10-29

    Methods, systems and computer program products are disclosed for measuring a performance of a program running on a processing unit of a processing system. In one embodiment, the method comprises informing a logic unit of each instruction in the program that is executed by the processing unit, assigning a weight to each instruction, assigning the instructions to a plurality of groups, and analyzing the plurality of groups to measure one or more metrics. In one embodiment, each instruction includes an operating code portion, and the assigning includes assigning the instructions to the groups based on the operating code portions of the instructions. In an embodiment, each type of instruction is assigned to a respective one of the plurality of groups. These groups may be combined into a plurality of sets of the groups.

  3. Optimization of high count rate event counting detector with Microchannel Plates and quad Timepix readout

    NASA Astrophysics Data System (ADS)

    Tremsin, A. S.; Vallerga, J. V.; McPhate, J. B.; Siegmund, O. H. W.

    2015-07-01

    Many high resolution event counting devices process one event at a time and cannot register simultaneous events. In this article a frame-based readout event counting detector consisting of a pair of Microchannel Plates and a quad Timepix readout is described. More than 104 simultaneous events can be detected with a spatial resolution of ~55 μm, while >103 simultaneous events can be detected with <10 μm spatial resolution when event centroiding is implemented. The fast readout electronics is capable of processing >1200 frames/sec, while the global count rate of the detector can exceed 5×108 particles/s when no timing information on every particle is required. For the first generation Timepix readout, the timing resolution is limited by the Timepix clock to 10-20 ns. Optimization of the MCP gain, rear field voltage and Timepix threshold levels are crucial for the device performance and that is the main subject of this article. These devices can be very attractive for applications where the photon/electron/ion/neutron counting with high spatial and temporal resolution is required, such as energy resolved neutron imaging, Time of Flight experiments in lidar applications, experiments on photoelectron spectroscopy and many others.

  4. Can we properly model the neutron monitor count rate?

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka; Usoskin, Ilya G.; Kovaltsov, Gennady A.; Mishev, Alexander L.; Corti, Claudio; Bindi, Veronica

    2015-09-01

    Neutron monitors provide continuous measurements of secondary nucleonic particles produced in the atmosphere by the primary cosmic rays and form the main tool to study the heliospheric modulation of cosmic rays. In order to study cosmic rays using the world network of neutron monitor and needs to be able to model the neutron monitor count rate. Earlier it was difficult because of the poorly known yield function, which has been essentially revisited recently. We have presented a verification of the new yield function of the standard neutron monitor (NM) using a recently released data on the direct in situ measurements of the galactic cosmic rays energy spectrum during 2006-2009 (the period of the record high cosmic ray flux) by Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics spaceborne spectrometer, and on NM latitude surveys performed during the period of 1994-2007, including periods of high solar activity. We found a very good agreement between the measured count rates of sea level NMs and the modeled ones in very different conditions: from low to high solar activity and from polar to tropical regions. This implies that the count rate of a sea level neutron monitor can be properly modeled in all conditions, using the new yield function.

  5. High-rate counting efficiency of VLPC

    SciTech Connect

    Hogue, H.H.

    1998-11-01

    A simple model is applied to describe dependencies of Visible Light Photon Counter (VLPC) characteristics on temperature and operating voltage. Observed counting efficiency losses at high illumination, improved by operating at higher temperature, are seen to be a consequence of de-biasing within the VLPC structure. A design improvement to minimize internal de-biasing for future VLPC generations is considered. {copyright} {ital 1998 American Institute of Physics.}

  6. Performance of a four-element Si drift detector for X-ray absorption fine-structure spectroscopy: resolution, maximum count rate, and dead-time correction with incorporation into the ATHENA data analysis software

    SciTech Connect

    Woicik, J.C.; Newburgh, W.; Ravel, B.; Fischer, D.A.

    2010-03-09

    The performance of a four-element Si drift detector for energy-dispersive fluorescence-yield X-ray absorption fine-structure measurements is reported, operating at the National Institute of Standards and Technology beamline X23A2 at the National Synchrotron Light Source. The detector can acquire X-ray absorption fine-structure spectra with a throughput exceeding 4 x 10{sup 5} counts per second per detector element (>1.6 x 10{sup 6} total counts per second summed over all four channels). At this count rate the resolution at 6 keV is approximately 220 eV, which adequately resolves the Mn K{sub {alpha}} and K{sup {beta}} fluorescence lines. Accurate dead-time correction is demonstrated, and it has been incorporated into the ATHENA data analysis program. To maintain counting efficiency and high signal to background, it is suggested that the incoming count rate should not exceed {approx}70% of the maximum throughput.

  7. Clear-PEM system counting rates: a Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Rodrigues, P.; Trindade, A.; Varela, J.

    2007-01-01

    Positron Emission Mammography (PEM) with 18F-Fluorodeoxyglucose (18F-FDG) is a functional imaging technique for breast cancer detection. The development of dedicated imaging systems with high sensitivity and spatial resolution are crucial for early breast cancer diagnosis and an efficient therapy. Clear-PEM is a dual planar scanner designed for high-resolution breast cancer imaging under development by the Portuguese PET Mammography consortium within the Crystal Clear Collaboration. It brings together a favorable combination of high-density scintillator crystals coupled to compact photodetectors, arranged in a double readout scheme capable of providing depth-of-interaction information. A Monte Carlo study of the Clear-PEM system counting rates is presented in this paper. Hypothetical breast exam scenarios were simulated to estimate the single event rates, true and random coincidence rates. A realistic description of the patient and detector geometry, radiation environment, physics and instrumentation factors was adopted in this work. Special attention was given to the 18F-FDG accumulation in the patient torso organs which, for the Clear-PEM scanner, represent significant activity outside the field-of-view (FOV) contributing to an increase of singles, randoms and scattered coincidences affecting the overall system performance. The potential benefits of patient shielding to minimize the influence of the out-of-field background was explored. The influence of LYSO:Ce crystal intrinsic natural activity due to the presence of the 176Lu isotope on the counting rate performance of the proposed scanner, was also investigated.

  8. High count rate gamma camera with independent modules

    NASA Astrophysics Data System (ADS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2015-11-01

    Advances in nuclear medical imaging are based on the improvements of the detector's performance. Generally the research is focussed on the spatial resolution improvement. However, another important parameter is the acquisition time that can significantly affect performance in some clinical investigation (e.g. first-pass cardiac studies). At present, there are several clinical imaging systems which are able to solve these diagnostic requirements, such as the D-SPECT Cardiac Imaging System (Spectrum Dynamics) or the Nucline Cardiodesk Medical Imaging System (Mediso). Actually, these solutions are organ-specific dedicated systems, while it would be preferable having general purpose planar detectors with high counting rate. Our group has recently introduced the use of scintillation matrices whose size is equal to the overall area of a position sensitive photomultiplier tube (PSPMT) in order to design a modular gamma camera. This study allowed optimising the overall pixel identification by improving and controlling the light collection efficiency of each PSPMT. Although we achieved a solution for the problems about the dead area at the junction of the PSPMTs when they are set side by side. In this paper, we propose a modular gamma camera design as the basis to build large area detectors. The modular detector design allows us to achieve better counting performance. In this approach, each module that is made of one or more PSPMTs, can actually acquire data independently and simultaneously, increasing the overall detection efficiency. To verify the improvement in count rate capability we have built two detectors with a field of view of ~ 5 × 5cm2, by using four R8900-C12 PSPMTs (Hamamatsu Photonics K.K.). Each PSPMT was coupled to a dedicated discrete scintillation structure designed to obtain a good homogeneity, high imaging performance and high efficiency. One of the detectors was designed as a standard gamma camera, while the other was composed by four independent

  9. Dark count rates in the STIS FUV MAMA

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2015-09-01

    Dark count rates in the STIS FUV MAMA are regularly monitored. The observation sequence was altered from an earlier method to measure the rate as a function of time and temperature shortly after the instrument is turned on. The dark rate exhibits an approximately quadratic de-pendence on temperature. A recommendation for estimating the observation-specific dark rate is given.

  10. Compensated count-rate circuit for radiation survey meter

    DOEpatents

    Todd, Richard A.

    1981-01-01

    A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for counting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensated circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

  11. Highly stable high-rate discriminator for nuclear counting

    NASA Technical Reports Server (NTRS)

    English, J. J.; Howard, R. H.; Rudnick, S. J.

    1969-01-01

    Pulse amplitude discriminator is specially designed for nuclear counting applications. At very high rates, the threshold is stable. The output-pulse width and the dead time change negligibly. The unit incorporates a provision for automatic dead-time correction.

  12. Compensated count-rate circuit for radiation survey meter

    DOEpatents

    Todd, R.A.

    1980-05-12

    A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for couting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensation circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

  13. Multianode cylindrical proportional counter for high count rates

    DOEpatents

    Hanson, James A.; Kopp, Manfred K.

    1981-01-01

    A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (<60 keV) at count rates of greater than 10.sup.5 counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

  14. Multianode cylindrical proportional counter for high count rates

    DOEpatents

    Hanson, J.A.; Kopp, M.K.

    1980-05-23

    A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (< 60 keV) at count rates of greater than 10/sup 5/ counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

  15. Full-counting statistics of random transition-rate matrices.

    PubMed

    Mordovina, Uliana; Emary, Clive

    2013-12-01

    We study the full-counting statistics of current of large open systems through the application of random-matrix theory to transition-rate matrices. We develop a method for calculating the ensemble-averaged current-cumulant generating functions based on an expansion in terms of the inverse system size. We investigate how different symmetry properties and different counting schemes affect the results. PMID:24483426

  16. Reducing the Teen Death Rate. KIDS COUNT Indicator Brief

    ERIC Educational Resources Information Center

    Shore, Rima; Shore, Barbara

    2009-01-01

    Life continues to hold considerable risk for adolescents in the United States. In 2006, the teen death rate stood at 64 deaths per 100,000 teens (13,739 teens) (KIDS COUNT Data Center, 2009). Although it has declined by 4 percent since 2000, the rate of teen death in this country remains substantially higher than in many peer nations, based…

  17. Performance of single-photon-counting PILATUS detector modules

    PubMed Central

    Kraft, P.; Bergamaschi, A.; Broennimann, Ch.; Dinapoli, R.; Eikenberry, E. F.; Henrich, B.; Johnson, I.; Mozzanica, A.; Schlepütz, C. M.; Willmott, P. R.; Schmitt, B.

    2009-01-01

    PILATUS is a silicon hybrid pixel detector system, operating in single-photon-counting mode, that has been developed at the Paul Scherrer Institut for the needs of macromolecular crystallography at the Swiss Light Source (SLS). A calibrated PILATUS module has been characterized with monochromatic synchrotron radiation. The influence of charge sharing on the count rate and the overall energy resolution of the detector were investigated. The dead-time of the system was determined using the attenuated direct synchrotron beam. A single module detector was also tested in surface diffraction experiments at the SLS, whereby its performance regarding fluorescence suppression and saturation tolerance were evaluated, and have shown to greatly improve the sensitivity, reliability and speed of surface diffraction data acquisition. PMID:19395800

  18. Total Gamma Count Rate Analysis Method for Nondestructive Assay Characterization

    SciTech Connect

    Cecilia R. Hoffman; Yale D. Harker

    2006-03-01

    A new approach to nondestructively characterize waste for disposal, based on total gamma response, has been developed at the Idaho Cleanup Project by CH2M-WG Idaho, LLC and Idaho State University, and is called the total gamma count rate analysis method. The total gamma count rate analysis method measures gamma interactions that produce energetic electrons or positrons in a detector. Based on previous experience with waste assays, the radionuclide content of the waste container is then determined. This approach potentially can yield minimum detection limits of less than 10 nCi/g. The importance of this method is twofold. First, determination of transuranic activity can be made for waste containers that are below the traditional minimum detection limits. Second, waste above 10 nCi/g and below 100 nCi/g can be identified, and a potential path for disposal resolved.

  19. Correcting the NICMOS count-rate dependent non-linearity

    NASA Astrophysics Data System (ADS)

    de Jong, Roelof S.

    2006-03-01

    We describe a routine to correct NICMOS imaging data for the NICMOS count-rate dependent non-linearity recently discovered by Bohlin et al. (2005) and quantified by deJong et al. (2006) and Bohlin et al. (2006). The routine has been implemented in the python scripting language and is callable from the shell command line and from iraf. The routine corrects NICMOS count-rate images assuming the non-linearity follows a powerlaw behavior. The wavelength dependence of the non-linearity is interpolated between the measured points of de Jong et al. (2006) and Bohlin et al. (2006) if necessary. The count rates in the output images are modified and hence the standard NICMOS calibration zero-points are no longer valid. New calibration zero-points have been derived from standard star images corrected with the routine. The routine was tested on the lamp-on/off data used in de Jong et al. (2006) to measure the non-linearity effect. We apply the correction to the NGC1850 stellar cluster field and the Hubble Ultra Deep Field (HUDF) to show the magnitude offsets expected due to the non-linearity on objects with a range in luminosity and surface brightness.

  20. The use of noise equivalent count rate and the NEMA phantom for PET image quality evaluation.

    PubMed

    Yang, Xin; Peng, Hao

    2015-03-01

    PET image quality is directly associated with two important parameters among others: count-rate performance and image signal-to-noise ratio (SNR). The framework of noise equivalent count rate (NECR) was developed back in the 1990s and has been widely used since then to evaluate count-rate performance for PET systems. The concept of NECR is not entirely straightforward, however, and among the issues requiring clarification are its original definition, its relationship to image quality, and its consistency among different derivation methods. In particular, we try to answer whether a higher NECR measurement using a standard NEMA phantom actually corresponds to better imaging performance. The paper includes the following topics: 1) revisiting the original analytical model for NECR derivation; 2) validating three methods for NECR calculation based on the NEMA phantom/standard; and 3) studying the spatial dependence of NECR and quantitative relationship between NECR and image SNR. PMID:25622772

  1. A Calibration of NICMOS Camera 2 for Low Count Rates

    NASA Astrophysics Data System (ADS)

    Rubin, D.; Aldering, G.; Amanullah, R.; Barbary, K.; Dawson, K. S.; Deustua, S.; Faccioli, L.; Fadeyev, V.; Fakhouri, H. K.; Fruchter, A. S.; Gladders, M. D.; de Jong, R. S.; Koekemoer, A.; Krechmer, E.; Lidman, C.; Meyers, J.; Nordin, J.; Perlmutter, S.; Ripoche, P.; Schlegel, D. J.; Spadafora, A.; Suzuki, N.

    2015-05-01

    NICMOS 2 observations are crucial for constraining distances to most of the existing sample of z\\gt 1 SNe Ia. Unlike conventional calibration programs, these observations involve long exposure times and low count rates. Reciprocity failure is known to exist in HgCdTe devices and a correction for this effect has already been implemented for high and medium count rates. However, observations at faint count rates rely on extrapolations. Here instead, we provide a new zero-point calibration directly applicable to faint sources. This is obtained via inter-calibration of NIC2 F110W/F160W with the Wide Field Camera 3 (WFC3) in the low count-rate regime using z∼ 1 elliptical galaxies as tertiary calibrators. These objects have relatively simple near-IR spectral energy distributions, uniform colors, and their extended nature gives a superior signal-to-noise ratio at the same count rate than would stars. The use of extended objects also allows greater tolerances on point-spread function profiles. We find space telescope magnitude zero points (after the installation of the NICMOS cooling system, NCS) of 25.296\\+/- 0.022 for F110W and 25.803\\+/- 0.023 for F160W, both in agreement with the calibration extrapolated from count rates ≳1000 times larger (25.262 and 25.799). Before the installation of the NCS, we find 24.843\\+/- 0.025 for F110W and 25.498\\+/- 0.021 for F160W, also in agreement with the high-count-rate calibration (24.815 and 25.470). We also check the standard bandpasses of WFC3 and NICMOS 2 using a range of stars and galaxies at different colors and find mild tension for WFC3, limiting the accuracy of the zero points. To avoid human bias, our cross-calibration was “blinded” in that the fitted zero-point differences were hidden until the analysis was finalized. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555, under programs

  2. Variability analysis in low count rate sources. [in astrophysics

    NASA Technical Reports Server (NTRS)

    Collura, A.; Maggio, A.; Sciortino, S.; Serio, S.; Vaiana, G. S.

    1987-01-01

    A method, based on the chi-square statistics, is described for detecting pulselike time variability in low count rate sources observed with photon-counting instruments. This method can be used even in the presence of observational gaps, takes full advantage of the filtering effect due to binning with different bin sizes, and takes into account the arbitrariness introduced by the binning phase. The procedure developed to limit the dependence of the results on the binning phase and ensure statistically correct results is described along with the application of the proposed procedure to a model of a variable source. Monte Carlo simulations are used to show how the method can be used to derive the characteristic variability time scales and that the method is more sensitive than the nonparametric Kolmogorov-Smirnov test in detecting variability to a given confidence level.

  3. Flow rate calibration for absolute cell counting rationale and design.

    PubMed

    Walker, Clare; Barnett, David

    2006-05-01

    There is a need for absolute leukocyte enumeration in the clinical setting, and accurate, reliable (and affordable) technology to determine absolute leukocyte counts has been developed. Such technology includes single platform and dual platform approaches. Derivations of these counts commonly incorporate the addition of a known number of latex microsphere beads to a blood sample, although it has been suggested that the addition of beads to a sample may only be required to act as an internal quality control procedure for assessing the pipetting error. This unit provides the technical details for undertaking flow rate calibration that obviates the need to add reference beads to each sample. It is envisaged that this report will provide the basis for subsequent clinical evaluations of this novel approach. PMID:18770842

  4. Advanced Reference Counting Pointers for Better Performance

    NASA Technical Reports Server (NTRS)

    Reinholtz, William

    2007-01-01

    A computer program implements reference counting pointers (RCPs) that are lock-free, thread-safe, async-safe, and operational on a multiprocessor computer. RCPs are powerful and convenient means of managing heap memory in C++ software. Most prior RCP programs use locks to ensure thread safety and manage concurrency. The present program was developed in a continuing effort to explore ways of using the C++ programming language to develop safety-critical and mission- critical software. This effort includes exploration of lock-free algorithms because they offer potential to avoid some costly and difficult verification problems. Unlike previously published RCP software, the present program does not use locks (meaning that no thread can block progress on another thread): Instead, this program implements algorithms that exploit capabilities of central-processing- unit hardware so as to avoid locks. Once locks are eliminated, it becomes possible to realize the other attributes mentioned in the first sentence. In addition to the abovementioned attributes, this program offers several advantages over other RCP programs that use locks: It is smaller (and, hence, is faster and uses less memory), it is immune to priority inversion, and there is no way for it to cause a C++ exception.

  5. Use of an in-field-of-view shield to improve count rate performance of the single crystal layer high-resolution research tomograph PET scanner for small animal brain scans.

    PubMed

    Boellaard, R; de Jong, H W A M; Molthoff, C F M; Buijs, F; Lenox, M; Nutt, R; Lammertsma, A A

    2003-12-01

    The count rate performance of the single LSO crystal layer high-resolution research tomograph (HRRT-S) PET scanner is limited by the processing speed of its electronics. Therefore, the feasibility of using an in-field-of-view (in-FOV) shield to improve the noise equivalent count rates (NECR) for small animal brain studies was investigated. The in-FOV shield consists of a lead tube of 12 cm length, 6 cm inner diameter and 9 mm wall thickness. It is large enough to shield the activity in the body of a rat or mouse. First, the effect of this shield on NECR was studied. Secondly, a number of experiments were performed to assess the effects of the shield on the accuracy of transmission scan data and, next, on reconstructed activity distribution in the brain. For activities below 150 MBq NECR improved only by 5-10%. For higher activities NECR maxima of 1.2E4 cps at 200 MBq and 2.2E4 cps at 370 MBq were found without and with shield, respectively. Listmode data taken without shield, however, were corrupted for activities above 75 MBq due to data overrun problems (time tag losses) of the electronics. When the shield was used data overrun was avoided up to activities of 150 MBq. For the unshielded part of the phantom, transmission scan data were the same with and without shield. The estimated scatter contribution was approximately 8.5% without and 5.5% with shield. Reconstructed emission data showed a difference up to 5% in the unshielded part of the phantom at 5 mm or more from the edge of the shielding. Of this 5% about 3% results from the difference in the uncorrected scatter contribution. In conclusion, an in-FOV shield can be used successfully in an HRRT PET scanner to improve NECR and accuracy of small animal brain studies. The latter is especially important when high activities are required for tracers with low brain uptake or when multiple animals are scanned simultaneously. PMID:14703172

  6. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors.

    PubMed

    Hsieh, Scott S; Pelc, Norbert J

    2014-06-01

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard energy-integrating x-ray detectors, but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a 'hybrid' detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al 2011 Med. Phys. 38 1089-102). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping ('bowtie') filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of 2 to 3. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable detectors. PMID

  7. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors

    NASA Astrophysics Data System (ADS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-06-01

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard energy-integrating x-ray detectors, but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a ‘hybrid’ detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al 2011 Med. Phys. 38 1089-102 ). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping (‘bowtie’) filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of 2 to 3. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable detectors.

  8. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors

    PubMed Central

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-01-01

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard, energy-integrating x-ray detectors but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a “hybrid” detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al, Med Phys 2011). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping (“bowtie”) filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of two to three. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable detectors. PMID

  9. Separating Spike Count Correlation from Firing Rate Correlation

    PubMed Central

    Vinci, Giuseppe; Ventura, Valérie; Smith, Matthew A.; Kass, Robert E.

    2016-01-01

    Populations of cortical neurons exhibit shared fluctuations in spiking activity over time. When measured for a pair of neurons over multiple repetitions of an identical stimulus, this phenomenon emerges as correlated trial-to-trial response variability via spike count correlation (SCC). However, spike counts can be viewed as noisy versions of firing rates, which can vary from trial to trial. From this perspective, the SCC for a pair of neurons becomes a noisy version of the corresponding firing-rate correlation (FRC). Furthermore, the magnitude of the SCC is generally smaller than that of the FRC, and is likely to be less sensitive to experimental manipulation. We provide statistical methods for disambiguating time-averaged drive from within-trial noise, thereby separating FRC from SCC. We study these methods to document their reliability, and we apply them to neurons recorded in vivo from area V4, in an alert animal. We show how the various effects we describe are reflected in the data: within-trial effects are largely negligible, while attenuation due to trial-to-trial variation dominates, and frequently produces comparisons in SCC that, because of noise, do not accurately reflect those based on the underlying FRC. PMID:26942746

  10. Separating Spike Count Correlation from Firing Rate Correlation.

    PubMed

    Vinci, Giuseppe; Ventura, Valérie; Smith, Matthew A; Kass, Robert E

    2016-05-01

    Populations of cortical neurons exhibit shared fluctuations in spiking activity over time. When measured for a pair of neurons over multiple repetitions of an identical stimulus, this phenomenon emerges as correlated trial-to-trial response variability via spike count correlation (SCC). However, spike counts can be viewed as noisy versions of firing rates, which can vary from trial to trial. From this perspective, the SCC for a pair of neurons becomes a noisy version of the corresponding firing rate correlation (FRC). Furthermore, the magnitude of the SCC is generally smaller than that of the FRC and is likely to be less sensitive to experimental manipulation. We provide statistical methods for disambiguating time-averaged drive from within-trial noise, thereby separating FRC from SCC. We study these methods to document their reliability, and we apply them to neurons recorded in vivo from area V4 in an alert animal. We show how the various effects we describe are reflected in the data: within-trial effects are largely negligible, while attenuation due to trial-to-trial variation dominates and frequently produces comparisons in SCC that, because of noise, do not accurately reflect those based on the underlying FRC. PMID:26942746

  11. Count rate capability considerations and results for a positron emission tomograph

    SciTech Connect

    Yamamoto, S.; Amano, M.; Hirose, Y.; Iida, H.; Miura, S.; Kanno, I.

    1989-02-01

    Count rate capability is an important characteristic for quantitative measurements in positron emission tomography (PET), especially for fast dynamic studies. Insufficient count rate capability reduces effective sensitivity and counting statistics of images at high count rate as well as quantification. Count rate capability is affected by many factors. The factors are categorized as follows: (1) factor of object size to be scanned, (2) factor of geometrical design of PET, (3) factor on electronics of PET. The purpose of this paper is to evaluate system count rate capabilities by changing these factors, and to estimate dominant ones.

  12. Effects of Perceptually Rich Manipulatives on Preschoolers' Counting Performance: Established Knowledge Counts

    ERIC Educational Resources Information Center

    Petersen, Lori A.; McNeil, Nicole M.

    2013-01-01

    Educators often use concrete objects to help children understand mathematics concepts. However, findings on the effectiveness of concrete objects are mixed. The present study examined how two factors--perceptual richness and established knowledge of the objects--combine to influence children's counting performance. In two experiments, preschoolers…

  13. Quantum-counting CT in the regime of count-rate paralysis: introduction of the pile-up trigger method

    NASA Astrophysics Data System (ADS)

    Kappler, S.; Hölzer, S.; Kraft, E.; Stierstorfer, K.; Flohr, T.

    2011-03-01

    The application of quantum-counting detectors in clinical Computed Tomography (CT) is challenged by extreme X-ray fluxes provided by modern high-power X-ray tubes. Scanning of small objects or sub-optimal patient positioning may lead to situations where those fluxes impinge on the detector without attenuation. Even in operation modes optimized for high-rate applications, with small pixels and high bias voltage, CdTe/CdZnTe detectors deliver pulses in the range of several nanoseconds. This can result in severe pulse pile-up causing detector paralysis and ambiguous detector signals. To overcome this problem we introduce the pile-up trigger, a novel method that provides unambiguous detector signals in rate regimes where classical rising-edge counters run into count-rate paralysis. We present detailed CT image simulations assuming ideal sensor material not suffering from polarization effects at high X-ray fluxes. This way we demonstrate the general feasibility of the pile-up trigger method and quantify resulting imaging properties such as contrasts, image noise and dual-energy performance in the high-flux regime of clinical CT devices.

  14. A count rate based contamination control standard for electron accelerators

    SciTech Connect

    May, R.T.; Schwahn, S.O.

    1996-12-31

    Accelerators of sufficient energy and particle fluence can produce radioactivity as an unwanted byproduct. The radioactivity is typically imbedded in structural materials but may also be removable from surfaces. Many of these radionuclides decay by positron emission or electron capture; they often have long half lives and produce photons of low energy and yield making detection by standard devices difficult. The contamination control limit used throughout the US nuclear industry and the Department of Energy is 1,000 disintegrations per minute. This limit is based on the detection threshold of pancake type Geiger-Mueller probes for radionuclides of relatively high radiotoxicity, such as cobalt-60. Several radionuclides of concern at a high energy electron accelerator are compared in terms of radiotoxicity with radionuclides commonly found in the nuclear industry. Based on this comparison, a count-rate based contamination control limit and associated measurement strategy is proposed which provides adequate detection of contamination at accelerators without an increase in risk.

  15. A fast position sensitive microstrip-gas-chamber detector at high count rate operation

    NASA Astrophysics Data System (ADS)

    Dolbnya, I. P.; Alberda, H.; Hartjes, F. G.; Udo, F.; Bakker, R. E.; Konijnenburg, M.; Homan, E.; Cerjak, I.; Goedtkindt, P.; Bras, W.

    2002-11-01

    Testing of a newly developed position sensitive high count rate microstrip gas chamber (MSGC) detector at high count rate operation has been carried out at the Dutch-Belgian x-ray scattering beamline at the European Synchrotron Radiation Facility (Grenoble, France) with a high intensity x-ray beam. The measurements show local count rate capabilities up to approx4.5 x105 counts/s/channel. Experimental data taken with this detector are also shown. These tests show that both time resolution down to 1.5 ms/frame and a reliable operation at high counting rates can be achieved.

  16. Reducing the Child Poverty Rate. KIDS COUNT Indicator Brief

    ERIC Educational Resources Information Center

    Shore, Rima; Shore, Barbara

    2009-01-01

    In 2007, nearly one in five or 18 percent of children in the U.S. lived in poverty (KIDS COUNT Data Center, 2009). Many of these children come from minority backgrounds. African American (35 percent), American Indian (33 percent) and Latino (27 percent) children are more likely to live in poverty than their white (11 percent) and Asian (12…

  17. High event rate ROICs (HEROICs) for astronomical UV photon counting detectors

    NASA Astrophysics Data System (ADS)

    Harwit, Alex; France, Kevin; Argabright, Vic; Franka, Steve; Freymiller, Ed; Ebbets, Dennis

    2014-07-01

    The next generation of astronomical photocathode / microchannel plate based UV photon counting detectors will overcome existing count rate limitations by replacing the anode arrays and external cabled electronics with anode arrays integrated into imaging Read Out Integrated Circuits (ROICs). We have fabricated a High Event Rate ROIC (HEROIC) consisting of a 32 by 32 array of 55 μm square pixels on a 60 μm pitch. The pixel sensitivity (threshold) has been designed to be globally programmable between 1 × 103 and 1 × 106 electrons. To achieve the sensitivity of 1 × 103 electrons, parasitic capacitances had to be minimized and this was achieved by fabricating the ROIC in a 65 nm CMOS process. The ROIC has been designed to support pixel counts up to 4096 events per integration period at rates up to 1 MHz per pixel. Integration time periods can be controlled via an external signal with a time resolution of less than 1 microsecond enabling temporally resolved imaging and spectroscopy of astronomical sources. An electrical injection port is provided to verify functionality and performance of each ROIC prior to vacuum integration with a photocathode and microchannel plate amplifier. Test results on the first ROICs using the electrical injection port demonstrate sensitivities between 3 × 103 and 4 × 105 electrons are achieved. A number of fixes are identified for a re-spin of this ROIC.

  18. A burst-mode photon counting receiver with automatic channel estimation and bit rate detection

    NASA Astrophysics Data System (ADS)

    Rao, Hemonth G.; DeVoe, Catherine E.; Fletcher, Andrew S.; Gaschits, Igor D.; Hakimi, Farhad; Hamilton, Scott A.; Hardy, Nicholas D.; Ingwersen, John G.; Kaminsky, Richard D.; Moores, John D.; Scheinbart, Marvin S.; Yarnall, Timothy M.

    2016-04-01

    We demonstrate a multi-rate burst-mode photon-counting receiver for undersea communication at data rates up to 10.416 Mb/s over a 30-foot water channel. To the best of our knowledge, this is the first demonstration of burst-mode photon-counting communication. With added attenuation, the maximum link loss is 97.1 dB at λ=517 nm. In clear ocean water, this equates to link distances up to 148 meters. For λ=470 nm, the achievable link distance in clear ocean water is 450 meters. The receiver incorporates soft-decision forward error correction (FEC) based on a product code of an inner LDPC code and an outer BCH code. The FEC supports multiple code rates to achieve error-free performance. We have selected a burst-mode receiver architecture to provide robust performance with respect to unpredictable channel obstructions. The receiver is capable of on-the-fly data rate detection and adapts to changing levels of signal and background light. The receiver updates its phase alignment and channel estimates every 1.6 ms, allowing for rapid changes in water quality as well as motion between transmitter and receiver. We demonstrate on-the-fly rate detection, channel BER within 0.2 dB of theory across all data rates, and error-free performance within 1.82 dB of soft-decision capacity across all tested code rates. All signal processing is done in FPGAs and runs continuously in real time.

  19. Exploration of maximum count rate capabilities for large-area photon counting arrays based on polycrystalline silicon thin-film transistors

    NASA Astrophysics Data System (ADS)

    Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua

    2016-03-01

    Pixelated photon counting detectors with energy discrimination capabilities are of increasing clinical interest for x-ray imaging. Such detectors, presently in clinical use for mammography and under development for breast tomosynthesis and spectral CT, usually employ in-pixel circuits based on crystalline silicon - a semiconductor material that is generally not well-suited for economic manufacture of large-area devices. One interesting alternative semiconductor is polycrystalline silicon (poly-Si), a thin-film technology capable of creating very large-area, monolithic devices. Similar to crystalline silicon, poly-Si allows implementation of the type of fast, complex, in-pixel circuitry required for photon counting - operating at processing speeds that are not possible with amorphous silicon (the material currently used for large-area, active matrix, flat-panel imagers). The pixel circuits of two-dimensional photon counting arrays are generally comprised of four stages: amplifier, comparator, clock generator and counter. The analog front-end (in particular, the amplifier) strongly influences performance and is therefore of interest to study. In this paper, the relationship between incident and output count rate of the analog front-end is explored under diagnostic imaging conditions for a promising poly-Si based design. The input to the amplifier is modeled in the time domain assuming a realistic input x-ray spectrum. Simulations of circuits based on poly-Si thin-film transistors are used to determine the resulting output count rate as a function of input count rate, energy discrimination threshold and operating conditions.

  20. Detecting trends in raptor counts: power and type I error rates of various statistical tests

    USGS Publications Warehouse

    Hatfield, J.S.; Gould, W.R., IV; Hoover, B.A.; Fuller, M.R.; Lindquist, E.L.

    1996-01-01

    We conducted simulations that estimated power and type I error rates of statistical tests for detecting trends in raptor population count data collected from a single monitoring site. Results of the simulations were used to help analyze count data of bald eagles (Haliaeetus leucocephalus) from 7 national forests in Michigan, Minnesota, and Wisconsin during 1980-1989. Seven statistical tests were evaluated, including simple linear regression on the log scale and linear regression with a permutation test. Using 1,000 replications each, we simulated n = 10 and n = 50 years of count data and trends ranging from -5 to 5% change/year. We evaluated the tests at 3 critical levels (alpha = 0.01, 0.05, and 0.10) for both upper- and lower-tailed tests. Exponential count data were simulated by adding sampling error with a coefficient of variation of 40% from either a log-normal or autocorrelated log-normal distribution. Not surprisingly, tests performed with 50 years of data were much more powerful than tests with 10 years of data. Positive autocorrelation inflated alpha-levels upward from their nominal levels, making the tests less conservative and more likely to reject the null hypothesis of no trend. Of the tests studied, Cox and Stuart's test and Pollard's test clearly had lower power than the others. Surprisingly, the linear regression t-test, Collins' linear regression permutation test, and the nonparametric Lehmann's and Mann's tests all had similar power in our simulations. Analyses of the count data suggested that bald eagles had increasing trends on at least 2 of the 7 national forests during 1980-1989.

  1. Dead time and count loss determination for radiation detection systems in high count rate applications

    NASA Astrophysics Data System (ADS)

    Patil, Amol

    This research is focused on dead time and the subsequent count loss estimation in radiation detection systems. The dead time is the minimum amount of time required between two events to permit detection of those events individually by a radiation detection system. If events occur during the system dead time, they are lost. Such lost information can be important in many applications including high-precision spectroscopy, positron emission tomography (PET), and the scanning of spent nuclear fuel. Understanding of the behavior of radiation detection systems is important; thus this work included a comprehensive review of dead time and pulse pile-up models and methods. The most common way to estimate detector dead time is by one-parameter approximations known as nonparalyzable and paralyzable models. This research proposes a two parameter model that estimates the detector paralysis factor and the dead time based on a graphical method. To determine the two parameters characteristics of a detection system, this work tested a novel technique to saturate the detector using a decaying source. The modified decaying source method, unlike other methods, does not assume the idealized behavior of detection system in use and calculates the overall dead time of the detection system. The paralysis factor for high purity germanium detection system was estimated approaching 100% and the dead time was on the order of 5--10 micros which compares well with the literature.

  2. Cryogenic, high-resolution x-ray detector with high count rate capability

    DOEpatents

    Frank, Matthias; Mears, Carl A.; Labov, Simon E.; Hiller, Larry J.; Barfknecht, Andrew T.

    2003-03-04

    A cryogenic, high-resolution X-ray detector with high count rate capability has been invented. The new X-ray detector is based on superconducting tunnel junctions (STJs), and operates without thermal stabilization at or below 500 mK. The X-ray detector exhibits good resolution (.about.5-20 eV FWHM) for soft X-rays in the keV region, and is capable of counting at count rates of more than 20,000 counts per second (cps). Simple, FET-based charge amplifiers, current amplifiers, or conventional spectroscopy shaping amplifiers can provide the electronic readout of this X-ray detector.

  3. Reducing the Child Death Rate. KIDS COUNT Indicator Brief

    ERIC Educational Resources Information Center

    Shore, Rima; Shore, Barbara

    2009-01-01

    In the 20th century's final decades, advances in the prevention and treatment of infectious diseases sharply reduced the child death rate. Despite this progress, the child death rate in the U.S. remains higher than in many other wealthy nations. The under-five mortality rate in the U.S. is almost three times higher than that of Iceland and Sweden…

  4. Statistical study of muons counts rates in differents directions, observed at the Brazilian Southern Space Observatory

    NASA Astrophysics Data System (ADS)

    Grams, Guilherme; Schuch, Nelson Jorge; Braga, Carlos Roberto; Purushottam Kane, Rajaram; Echer, Ezequiel; Ronan Coelho Stekel, Tardelli

    Cosmic ray are charged particles, at the most time protons, that reach the earth's magne-tosphere from interplanetary space with velocities greater than the solar wind. When these impinge the atmosphere, they interact with atmosphere constituents and decay into sub-particles forming an atmospheric shower. The muons are the sub-particles which normally maintain the originated direction of the primary cosmic ray. A multi-directional muon detec-tor (MMD) was installed in 2001 and upgraded in 2005, through an international cooperation between Brazil, Japan and USA, and operated since then at the Southern Space Observatory -SSO/CRS/CCR/INPE -MCT, (29,4° S, 53,8° W, 480m a.s.l.), São Martinho da Serra, RS, a Brazil. The main objetive of this work is to present a statistical analysis of the intensity of muons, with energy between 50 and 170 GeV, in differents directions, measured by the SSO's multi-directional muon detector. The analysis was performed with data from 2006 and 2007 collected by the SSO's MMD. The MMD consists of two layers of 4x7 detectors with a total observation area of 28 m2 . The counting of muons in each directional channel is made by a coincidence of pulses pair, one from a detector in the upper layer and the other from a detector in the lower layer. The SSO's MMD is equipped with 119 directional channels for muon count rate measurement and is capable of detecting muons incident with zenithal angle between 0° and 75,53° . A statistical analysis was made with the MMD muon count rate for all the di-rectional channels. The average and the standard deviation of the muon count rate in each directional component were calculated. The results show lower cont rate for the channels with larger zenith, and higher cont rate with smaller zenith, as expected from the production and propagation of muons in the atmosphere. It is also possible to identify the Stormer cone. The SSO's MMD is also a detector component of the Global Muon Detector Network (GMDN

  5. Unbiased estimation of mutation rates under fluctuating final counts.

    PubMed

    Ycart, Bernard; Veziris, Nicolas

    2014-01-01

    Estimation methods for mutation rates (or probabilities) in Luria-Delbrück fluctuation analysis usually assume that the final number of cells remains constant from one culture to another. We show that this leads to systematically underestimate the mutation rate. Two levels of information on final numbers are considered: either the coefficient of variation has been independently estimated, or the final number of cells in each culture is known. In both cases, unbiased estimation methods are proposed. Their statistical properties are assessed both theoretically and through Monte-Carlo simulation. As an application, the data from two well known fluctuation analysis studies on Mycobacterium tuberculosis are reexamined. PMID:24988217

  6. Diplomas Count: An Essential Guide to Graduation Policy and Rates

    ERIC Educational Resources Information Center

    Edwards, Virginia B., Ed.

    2006-01-01

    "Education Week" provides a weekly review of state and federal K-12 education policy news. In this issue it offers detailed data on graduation rates across the 50 states and the District of Columbia, and in the nation's 50 largest school districts. The analysis is based on the Cumulative Promotion Index developed by Christopher B. Swanson, the…

  7. Reducing the High School Dropout Rate. KIDS COUNT Indicator Brief

    ERIC Educational Resources Information Center

    Shore, Rima; Shore, Barbara

    2009-01-01

    Researchers use many different methods to calculate the high school dropout rate, and depending on the approach, the numbers can look very different. But, no matter which method is used, the key finding is the same: too many students are leaving school without the knowledge and skills they need to meet the demands of twenty-first century…

  8. Waveguide integrated low noise NbTiN nanowire single-photon detectors with milli-Hz dark count rate

    PubMed Central

    Schuck, Carsten; Pernice, Wolfram H. P.; Tang, Hong X.

    2013-01-01

    Superconducting nanowire single-photon detectors are an ideal match for integrated quantum photonic circuits due to their high detection efficiency for telecom wavelength photons. Quantum optical technology also requires single-photon detection with low dark count rate and high timing accuracy. Here we present very low noise superconducting nanowire single-photon detectors based on NbTiN thin films patterned directly on top of Si3N4 waveguides. We systematically investigate a large variety of detector designs and characterize their detection noise performance. Milli-Hz dark count rates are demonstrated over the entire operating range of the nanowire detectors which also feature low timing jitter. The ultra-low dark count rate, in combination with the high detection efficiency inherent to our travelling wave detector geometry, gives rise to a measured noise equivalent power at the 10−20 W/Hz1/2 level. PMID:23714696

  9. Note: Operation of gamma-ray microcalorimeters at elevated count rates using filters with constraints.

    PubMed

    Alpert, B K; Horansky, R D; Bennett, D A; Doriese, W B; Fowler, J W; Hoover, A S; Rabin, M W; Ullom, J N

    2013-05-01

    Microcalorimeter sensors operated near 0.1 K can measure the energy of individual x- and gamma-ray photons with significantly more precision than conventional semiconductor technologies. Both microcalorimeter arrays and higher per pixel count rates are desirable to increase the total throughput of spectrometers based on these devices. The millisecond recovery time of gamma-ray microcalorimeters and the resulting pulse pileup are significant obstacles to high per pixel count rates. Here, we demonstrate operation of a microcalorimeter detector at elevated count rates by use of convolution filters designed to be orthogonal to the exponential tail of a preceding pulse. These filters allow operation at 50% higher count rates than conventional filters while largely preserving sensor energy resolution. PMID:23742605

  10. Bone and gallium scans in mastocytosis: correlation with count rates, radiography, and microscopy

    SciTech Connect

    Ensslen, R.D.; Jackson, F.I.; Reid, A.M.

    1983-07-01

    Mastocytosis (urticaria pigmentosa) was proven in a patient suffering from severe back pain. A bone scan showed diffusely increased bone activity. Count rates were also abnormally elevated over several areas of the skeleton. Radiographs were consistent with mastocytosis in bone.

  11. Every second counts: innovations to increase timely defibrillation rates.

    PubMed

    Borak, Meredith; Francisco, Mary Ann; Stokas, Mary Ann; Maroney, Mary; Bednar, Valerie; Miller, Megan E; Pakieser-Reed, Katherine

    2014-01-01

    Early defibrillation is an essential step in the "chain of survival" for patients with in-hospital cardiac arrest. To increase the rate of early defibrillation by nurse first responders in noncritical care areas, our institution employed a quality resuscitation consultant, implemented nursing education programs, and standardized equipment and practices. Automated external defibrillator application by nurse first responders prior to advanced cardiac life support team arrival has improved from 15% in 2011 to 76% in 2013 (P < .001). PMID:24810907

  12. MERLIN, a new high count rate spectrometer at ISIS

    NASA Astrophysics Data System (ADS)

    Bewley, R. I.; Eccleston, R. S.; McEwen, K. A.; Hayden, S. M.; Dove, M. T.; Bennington, S. M.; Treadgold, J. R.; Coleman, R. L. S.

    2006-11-01

    MERLIN is designed to be a high intensity, medium energy resolution spectrometer. As such, it will complement the high-resolution MAPS spectrometer at ISIS. MERLIN will utilise all the latest advances in technology with a supermirror guide to enhance flux as well as 3 m long position-sensitive detectors in a vacuum making it ideal for single-crystal users. The detector bank will cover a massive π steradians of solid angle with an angular range from -45° to +135° degrees in the horizontal plane and ±30° degrees in the vertical plane. This will allow large swathes of Q, ω space to be accessed in a single run. The instrument will be ready for commissioning in February 2006. This paper presents details of design and performance of this new instrument.

  13. Respiratory rate: measurement of variability over time and accuracy at different counting periods.

    PubMed Central

    Simoes, E A; Roark, R; Berman, S; Esler, L L; Murphy, J

    1991-01-01

    The respiratory rates/minute of 97 children were monitored every 10-15 minutes over one hour, by an observer and by pneumogram, at which times two 30 second and one 60 second counts were obtained. The children were under 5 years of age with lower respiratory tract infections (n = 20), upper respiratory tract infections (n = 34), or controls without acute respiratory infection (n = 43). The difference between respiratory rate count determined simultaneously by observation and pneumogram in relation to their mean count was analysed for the 60 second counting period, 30 plus 30 second period, and the 30 second period doubled. The mean difference for the 60 second period was 1.79, for the 30 plus 30 second period 1.42, and for the 30 second period doubled 1.72. The variability between respiratory rate counts determined by observation and pneumogram was significantly lower in counts obtained when the subject was sleeping and higher when agitated compared with obtaining a count when the subject was awake and calm or feeding. The variability was also significantly lower in subjects with lower respiratory tract infections compared with those with upper respiratory tract infections and control subjects without respiratory symptoms. In the same patient, over the one hour, 50% of the 60 second counts varied by up to 14 breaths/minute and 75% by up to 21 breaths/minute. The least variability was seen in children with a lower respiratory tract infection, who tended to maintain their rapid breathing in contrast to those with an upper respiratory tract infection and controls without respiratory symptoms. About 10% of initial 30 second counts, 12% of 60 second, and 16% of initial and repeat 30 second attempts to obtain accurate counts failed. Failures occurred more frequently in children <2 months of age and those agitated. The data from this study suggest that one minute's counting either at a stretch or in two blocks of 30 second intervals is better than counting the respiratory

  14. Computational Performance Assessment of k-mer Counting Algorithms.

    PubMed

    Pérez, Nelson; Gutierrez, Miguel; Vera, Nelson

    2016-04-01

    This article is about the assessment of several tools for k-mer counting, with the purpose to create a reference framework for bioinformatics researchers to identify computational requirements, parallelizing, advantages, disadvantages, and bottlenecks of each of the algorithms proposed in the tools. The k-mer counters evaluated in this article were BFCounter, DSK, Jellyfish, KAnalyze, KHMer, KMC2, MSPKmerCounter, Tallymer, and Turtle. Measured parameters were the following: RAM occupied space, processing time, parallelization, and read and write disk access. A dataset consisting of 36,504,800 reads was used corresponding to the 14th human chromosome. The assessment was performed for two k-mer lengths: 31 and 55. Obtained results were the following: pure Bloom filter-based tools and disk-partitioning techniques showed a lesser RAM use. The tools that took less execution time were the ones that used disk-partitioning techniques. The techniques that made the major parallelization were the ones that used disk partitioning, hash tables with lock-free approach, or multiple hash tables. PMID:26982880

  15. Nuclear photonics at ultra-high counting rates and higher multipole excitations

    NASA Astrophysics Data System (ADS)

    Thirolf, P. G.; Habs, D.; Filipescu, D.; Gernhäuser, R.; Günther, M. M.; Jentschel, M.; Marginean, N.; Pietralla, N.

    2012-07-01

    Next-generation γ beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 1013 γ/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses (˜120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a γ pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 1018 γ/s, thus introducing major challenges in view of pile-up. Novel γ optics will be applied to monochromatize the γ beam to ultimately ΔE/E˜10-6. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding γ detectors, e.g. based on advanced scintillator technology (e.g. LaBr3(Ce)) allow for measurements with count rates as high as 106-107 γ/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr3 detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.

  16. Nuclear photonics at ultra-high counting rates and higher multipole excitations

    SciTech Connect

    Thirolf, P. G.; Habs, D.; Filipescu, D.; Gernhaeuser, R.; Guenther, M. M.; Jentschel, M.; Marginean, N.; Pietralla, N.

    2012-07-09

    Next-generation {gamma} beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 10{sup 13}{gamma}/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses ({approx}120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a {gamma} pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 10{sup 18}{gamma}/s, thus introducing major challenges in view of pile-up. Novel {gamma} optics will be applied to monochromatize the {gamma} beam to ultimately {Delta}E/E{approx}10{sup -6}. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding {gamma} detectors, e.g. based on advanced scintillator technology (e.g. LaBr{sub 3}(Ce)) allow for measurements with count rates as high as 10{sup 6}-10{sup 7}{gamma}/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr{sub 3} detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.

  17. Illinois Quality Counts: QRS Profile. The Child Care Quality Rating System (QRS) Assessment

    ERIC Educational Resources Information Center

    Child Trends, 2010

    2010-01-01

    This paper presents a profile of Illinois' Quality Counts prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for Family…

  18. Gain dispersion in Visible Light Photon Counters as a function of counting rate

    SciTech Connect

    Bross, A.; Buscher, V.; Estrada, J.; Ginther, G.; Molina, J.; /Rio de Janeiro State U.

    2005-03-01

    We present measurements of light signals using Visible Light Photon Counters (VLPC), that indicate an increase in gain dispersion as the counting rate increases. We show that this dispersion can be understood on the basis of a recent observation of localized field reduction in VLPCs at high input rates.

  19. Palm Beach Quality Counts: QRS Profile. The Child Care Quality Rating System (QRS) Assessment

    ERIC Educational Resources Information Center

    Child Trends, 2010

    2010-01-01

    This paper presents a profile of Palm Beach's Quality Counts prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for…

  20. Miami-Dade Quality Counts: QRS Profile. The Child Care Quality Rating System (QRS) Assessment

    ERIC Educational Resources Information Center

    Child Trends, 2010

    2010-01-01

    This paper presents a profile of Miami-Dade's Quality Counts prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for…

  1. Performance evaluation of a photon-counting intensified CCD

    NASA Astrophysics Data System (ADS)

    Bergamini, Paolo; Bonelli, Giuseppe; D'Angelo, Sergio; Latorre, Stefano; Poletto, Luca; Sechi, Giacomo; Tanzi, Enrico G.; Tondello, Giuseppe; Uslenghi, Michela

    1997-10-01

    The performance of a prototype photon counting imaging detector, being developed for the international UV space mission spectrum-UV, is presented. The detector is based on a 4-cm diameter, Z stack, high gain microchannel plate (MCP) intensifier endowed with a RbTe photocathode. The electron cascade generated by the MCP intensifier is transduced, via a phosphor screen and a 1:3.6 fiber optics reducer, into a 5 by 5 pixel(superscript 2), quasi-Gaussian charge distribution on a 15 micrometer, 512 by 512 pixel(superscript 2) format CCD matrix read out in the frame-transfer mode at 20 MHz, corresponding to 60 frame sec(superscript -1) in the full frame mode and to 220 frame sec(superscript -1) in the window (128 by 512 pixel(superscript 2)) mode. The data flow is acquired serially as to generate a 5 by 5 pixel(superscript 2) event sash that sweeps dynamically the CCD matrix at the 50 ns place of the readout clock. Each and every event sash is searched for the presence of events whose charge distribution lie within set thresholds and satisfy given morphological rules, i.e. a peaked charge profile. The centroid coordinates of identified events are subsequently determined with sub-pixel accuracy and stored in an external, high resolution memory. The data acquisition and processing system, based on field programmable gate array technology, is well able to resolve the front MCP pore geometry (10 micrometer diameter pores at 12 micrometer pitch).

  2. ADONIS, high count-rate HP-Ge {gamma} spectrometry algorithm: Irradiated fuel assembly measurement

    SciTech Connect

    Pin, P.; Barat, E.; Dautremer, T.; Montagu, T.; Normand, S.

    2011-07-01

    ADONIS is a digital system for gamma-ray spectrometry, developed by CEA. This system achieves high count-rate gamma-ray spectrometry with correct dynamic dead-time correction, up to, at least, more than an incoming count rate of 3.10{sup 6} events per second. An application of such a system at AREVA NC's La Hague plant is the irradiated fuel scanning facility before reprocessing. The ADONIS system is presented, then the measurement set-up and, last, the measurement results with reference measurements. (authors)

  3. Apparatus and method for temperature correction and expanded count rate of inorganic scintillation detectors

    DOEpatents

    Ianakiev, Kiril D.; Hsue, Sin Tao; Browne, Michael C.; Audia, Jeffrey M.

    2006-07-25

    The present invention includes an apparatus and corresponding method for temperature correction and count rate expansion of inorganic scintillation detectors. A temperature sensor is attached to an inorganic scintillation detector. The inorganic scintillation detector, due to interaction with incident radiation, creates light pulse signals. A photoreceiver processes the light pulse signals to current signals. Temperature correction circuitry that uses a fast light component signal, a slow light component signal, and the temperature signal from the temperature sensor to corrected an inorganic scintillation detector signal output and expanded the count rate.

  4. A high count rate position decoding and energy measuring method for nuclear cameras using Anger logic detectors

    SciTech Connect

    Wong, W.H.; Li, H.; Uribe, J.

    1998-06-01

    A new method for processing signals from Anger position-sensitive detectors used in gamma cameras and PET is proposed for very high count-rate imaging where multiple-event pileups are the norm. This method is designed to sort out and recover every impinging event from multiple-event pileups while maximizing the collection of scintillation signal for every event to achieve optimal accuracy in the measurement of energy and position. For every detected event, this method cancels the remnant signals from previous events, and excludes the pileup of signals from following events. The remnant subtraction is exact even for multiple pileup events. A prototype circuit for energy recovery demonstrated that the maximum count rates can be increased by more than 10 times comparing to the pulse-shaping method, and the energy resolution is as good as pulse shaping (or fixed integration) at low count rates. At 2 {times} 10{sup 6} events/sec on NaI(Tl), the true counts acquired with this method is 3.3 times more than the delay-line clipping method (256 ns clipping) due to events recovered from pileups. Pulse-height spectra up to 3.5 {times} 10{sup 6} events/sec have been studied. Monte Carlo simulation studies have been performed for image-quality comparisons between different processing methods.

  5. Optical People Counting for Demand Controlled Ventilation: A Pilot Study of Counter Performance

    SciTech Connect

    Fisk, William J.; Sullivan, Douglas

    2009-12-26

    This pilot scale study evaluated the counting accuracy of two people counting systems that could be used in demand controlled ventilation systems to provide control signals for modulating outdoor air ventilation rates. The evaluations included controlled challenges of the people counting systems using pre-planned movements of occupants through doorways and evaluations of counting accuracies when naive occupants (i.e., occupants unaware of the counting systems) passed through the entrance doors of the building or room. The two people counting systems had high counting accuracy accuracies, with errors typically less than 10percent, for typical non-demanding counting events. However, counting errors were high in some highly challenging situations, such as multiple people passing simultaneously through a door. Counting errors, for at least one system, can be very high if people stand in the field of view of the sensor. Both counting system have limitations and would need to be used only at appropriate sites and where the demanding situations that led to counting errors were rare.

  6. Influence of electron dose rate on electron counting images recorded with the K2 camera

    PubMed Central

    Li, Xueming; Zheng, Shawn Q.; Egami, Kiyoshi; Agard, David A.; Cheng, Yifan

    2013-01-01

    A recent technological breakthrough in electron cryomicroscopy (cryoEM) is the development of direct electron detection cameras for data acquisition. By bypassing the traditional phosphor scintillator and fiber optic coupling, these cameras have greatly enhanced sensitivity and detective quantum efficiency (DQE). Of the three currently available commercial cameras, the Gatan K2 Summit was designed specifically for counting individual electron events. Counting further enhances the DQE, allows for practical doubling of detector resolution and eliminates noise arising from the variable deposition of energy by each primary electron. While counting has many advantages, undercounting of electrons happens when more than one electron strikes the same area of the detector within the analog readout period (coincidence loss), which influences image quality. In this work, we characterized the K2 Summit in electron counting mode, and studied the relationship of dose rate and coincidence loss and its influence on the quality of counted images. We found that coincidence loss reduces low frequency amplitudes but has no significant influence on the signal-to-noise ratio of the recorded image. It also has little influence on high frequency signals. Images of frozen hydrated archaeal 20S proteasome (~700 kDa, D7 symmetry) recorded at the optimal dose rate retained both high-resolution signal and low-resolution contrast and enabled calculating a 3.6 Å three-dimensional reconstruction from only 10,000 particles. PMID:23968652

  7. Linear-log counting-rate meter uses transconductance characteristics of a silicon planar transistor

    NASA Technical Reports Server (NTRS)

    Eichholz, J. J.

    1969-01-01

    Counting rate meter compresses a wide range of data values, or decades of current. Silicon planar transistor, operating in the zero collector-base voltage mode, is used as a feedback element in an operational amplifier to obtain the log response.

  8. High counting rates of x-ray photon detection using APD detectors on synchrotron machines

    SciTech Connect

    Kakuno, E. M.; Giacomolli, B. A.; Scorzato, C. R.

    2012-05-17

    In this work we show the results of 10 x 10 mm{sup 2} Si-APD detector's test with guard ring detecting x-rays. The result of mapping surface is also exhibited. We show and discuss the difficulty of single photon detection in high counting rate experiments in synchrotrons machines.

  9. 45 CFR 261.25 - Do we count Tribal families in calculating the work participation rate?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Do we count Tribal families in calculating the work participation rate? 261.25 Section 261.25 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING...

  10. 45 CFR 261.25 - Do we count Tribal families in calculating the work participation rate?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true Do we count Tribal families in calculating the work participation rate? 261.25 Section 261.25 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING...

  11. 45 CFR 286.100 - What activities count towards the work participation rate?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false What activities count towards the work participation rate? 286.100 Section 286.100 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL TANF PROVISIONS...

  12. High energy resolution x-ray spectrometer for high count rate XRF applications

    SciTech Connect

    Rossington, C.S.; Madden, N.W.; Chapman, K.

    1993-08-01

    A new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) pr- eamplifier. The spectrometer operates at high count rates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 {mu}sec and a throughput count rate of 145,000 counts sec{sup {minus}1}, the energy resolution at 5.9 key is 220 eV FWHM. Commercially available spectrometers utilizing conventional geometry Si(Li) detectors with areas equivalent to the new detector have resolutions on the order of 540 eV under the same conditions. Conventional x-ray spectrometers offering high energy resolution must employ detectors with areas one-tenth the size of the new LBL detector (20 mm{sup 2} compared with 200 mm{sup 2}). However, even with the use of the smaller area detectors, the energy resolution of a commercial system is typically limited to approximately 300 eV (again, at 1 {mu}sec and 5.9 keV) due to the noise of the commercially available JFET`S. The new large area detector is useful in high count rate applications, but is also useful in the detection of weak photon signals, in which it is desirable to subtend as large an angle of the available photon flux as possible, while still maintaining excellent energy resolution. X-ray fluorescence data from the new spectrometer is shown in comparison to a commercially available system in the analysis of a dilute multi-element material, and also in conjunction with high count rate synchrotron EXAMS applications.

  13. Statistical treatment of photon/electron counting: extending the linear dynamic range from the dark count rate to saturation.

    PubMed

    Kissick, David J; Muir, Ryan D; Simpson, Garth J

    2010-12-15

    An experimentally simple photon counting method is demonstrated providing 7 orders of magnitude in linear dynamic range (LDR) for a single photomultiplier tube (PMT) detector. In conventional photon/electron counting methods, the linear range is dictated by the agreement between the binomially distributed measurement of counted events and the underlying Poisson distribution of photons/electrons. By explicitly considering the log-normal probability distribution in voltage transients as a function of the number of photons present and the Poisson distribution of photons, observed counts for a given threshold can be related to the mean number of photons well beyond the conventional limit. Analytical expressions are derived relating counts and photons that extend the linear range to an average of ∼11 photons arriving simultaneously with a single threshold. These expressions can be evaluated numerically for multiple thresholds extending the linear range to the saturation point of the PMT. The peak voltage distributions are experimentally shown to follow a Poisson weighted sum of log-normal distributions that can all be derived from the single photoelectron voltage peak-height distribution. The LDR that results from this method is compared to conventional single photon counting (SPC) and to signal averaging by analog to digital conversion (ADC). PMID:21114249

  14. Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging

    NASA Technical Reports Server (NTRS)

    Lu, Wei; Krainak, Michael A.; Yang, Guangning; Sun, Xiaoli; Merritt, Scott

    2016-01-01

    We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies ((is) greater than 50%) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.

  15. Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging

    NASA Technical Reports Server (NTRS)

    Lu, Wei; Krainak, Michael A.; Yang, Guan; Sun, Xiaoli; Merritt, Scott

    2016-01-01

    We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies (50) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.

  16. Improved count rate corrections for highest data quality with PILATUS detectors.

    PubMed

    Trueb, P; Sobott, B A; Schnyder, R; Loeliger, T; Schneebeli, M; Kobas, M; Rassool, R P; Peake, D J; Broennimann, C

    2012-05-01

    The PILATUS detector system is widely used for X-ray experiments at third-generation synchrotrons. It is based on a hybrid technology combining a pixelated silicon sensor with a CMOS readout chip. Its single-photon-counting capability ensures precise and noise-free measurements. The counting mechanism introduces a short dead-time after each hit, which becomes significant for rates above 10(6) photons s(-1) pixel(-1). The resulting loss in the number of counted photons is corrected for by applying corresponding rate correction factors. This article presents the results of a Monte Carlo simulation which computes the correction factors taking into account the detector settings as well as the time structure of the X-ray beam at the synchrotron. The results of the simulation show good agreement with experimentally determined correction factors for various detector settings at different synchrotrons. The application of accurate rate correction factors improves the X-ray data quality acquired at high photon fluxes. Furthermore, it is shown that the use of fast detector settings in combination with an optimized time structure of the X-ray beam allows for measurements up to rates of 10(7) photons s(-1) pixel(-1). PMID:22514168

  17. Performance and capacity analysis of Poisson photon-counting based Iter-PIC OCDMA systems.

    PubMed

    Li, Lingbin; Zhou, Xiaolin; Zhang, Rong; Zhang, Dingchen; Hanzo, Lajos

    2013-11-01

    In this paper, an iterative parallel interference cancellation (Iter-PIC) technique is developed for optical code-division multiple-access (OCDMA) systems relying on shot-noise limited Poisson photon-counting reception. The novel semi-analytical tool of extrinsic information transfer (EXIT) charts is used for analysing both the bit error rate (BER) performance as well as the channel capacity of these systems and the results are verified by Monte Carlo simulations. The proposed Iter-PIC OCDMA system is capable of achieving two orders of magnitude BER improvements and a 0.1 nats of capacity improvement over the conventional chip-level OCDMA systems at a coding rate of 1/10. PMID:24216821

  18. Simulation of Rate-Related (Dead-Time) Losses In Passive Neutron Multiplicity Counting Systems

    SciTech Connect

    Evans, L.G.; Norman, P.I.; Leadbeater, T.W.; Croft, S.; Philips, S.

    2008-07-01

    Passive Neutron Multiplicity Counting (PNMC) based on Multiplicity Shift Register (MSR) electronics (a form of time correlation analysis) is a widely used non-destructive assay technique for quantifying spontaneously fissile materials such as Pu. At high event rates, dead-time losses perturb the count rates with the Singles, Doubles and Triples being increasingly affected. Without correction these perturbations are a major source of inaccuracy in the measured count rates and assay values derived from them. This paper presents the simulation of dead-time losses and investigates the effect of applying different dead-time models on the observed MSR data. Monte Carlo methods have been used to simulate neutron pulse trains for a variety of source intensities and with ideal detection geometry, providing an event by event record of the time distribution of neutron captures within the detection system. The action of the MSR electronics was modelled in software to analyse these pulse trains. Stored pulse trains were perturbed in software to apply the effects of dead-time according to the chosen physical process; for example, the ideal paralysable (extending) and non-paralysable models with an arbitrary dead-time parameter. Results of the simulations demonstrate the change in the observed MSR data when the system dead-time parameter is varied. In addition, the paralysable and non-paralysable models of deadtime are compared. These results form part of a larger study to evaluate existing dead-time corrections and to extend their application to correlated sources. (authors)

  19. Effects of high count rate and gain shift on isotope identification algorithms

    SciTech Connect

    Robinson, Sean M.; Kiff, Scott D.; Ashbaker, Eric D.; Flumerfelt, Eric L.; Salvitti, Matthew

    2009-11-01

    Spectroscopic gamma-ray detectors are used for many research, industrial, and homeland- security applications. Thallium-doped sodium iodide, (NaI(Tl)), scintillation crystals coupled to photomultiplier tubes provide medium-resolution spectral data about the surrounding environment. NaI(Tl)-based detectors, paired with spectral identification algorithms, are often effective for identifying gamma-ray sources by isotope. However, intrinsic limitations for NaI(Tl) systems exist, including gain shifts and spectral marring (e.g., loss of resolution and count-rate saturation) at high count rates. These effects are hardware dependent and have strong effects on the radioisotopic identification capability of NaI(Tl)-based systems. In this work, the effects of high count rate on the response of isotope-identification algorithms are explored. It is shown that a small gain shift of a few tens of keV is sufficient to disturb identification. The onset of this and other spectral effects is estimated for NaI(Tl) crystals, and a mechanism for mitigating these effects by estimating and correcting for them is implemented and evaluated.

  20. Effects of High Count Rate and Gain Shift on Isotope Identification Algorithms

    SciTech Connect

    Robinson, Sean M.; Kiff, Scott D.; Ashbaker, Eric D.; Bender, Sarah E.; Flumerfelt, Eric L.; Salvitti, Matthew; Borgardt, James D.; Woodring, Mitchell L.

    2007-12-31

    Spectroscopic gamma-ray detectors are used for many research applications, as well as Homeland Security screening applications. Sodium iodide (NaI) scintillator crystals coupled with photomultiplier tubes (PMTs) provide medium-resolution spectral data about the surrounding environment. NaI based detectors, paired with spectral identification algorithms, are often effective in identifying sources of interest by isotope. However, intrinsic limitations exist for NaI systems because of gain shifts and spectral marring (e.g., loss of resolution and count-rate saturation) at high count rates. These effects are hardware dependent, and have strong effects on the radioisotopic identification capability of these systems. In this work, the effects of high count rate on the capability of isotope identification algorithms are explored. It is shown that a small gain shift of a few tens of keV is sufficient to disturb identification. The onset of this and other spectral effects are estimated for several systems., and a mechanism for mitigating these effects by estimating and correcting for them is implemented and evaluated.

  1. Performance of in-pixel circuits for photon counting arrays (PCAs) based on polycrystalline silicon TFTs.

    PubMed

    Liang, Albert K; Koniczek, Martin; Antonuk, Larry E; El-Mohri, Youcef; Zhao, Qihua; Street, Robert A; Lu, Jeng Ping

    2016-03-01

    Photon counting arrays (PCAs), defined as pixelated imagers which measure the absorbed energy of x-ray photons individually and record this information digitally, are of increasing clinical interest. A number of PCA prototypes with a 1 mm pixel-to-pixel pitch have recently been fabricated with polycrystalline silicon (poly-Si)-a thin-film technology capable of creating monolithic imagers of a size commensurate with human anatomy. In this study, analog and digital simulation frameworks were developed to provide insight into the influence of individual poly-Si transistors on pixel circuit performance-information that is not readily available through empirical means. The simulation frameworks were used to characterize the circuit designs employed in the prototypes. The analog framework, which determines the noise produced by individual transistors, was used to estimate energy resolution, as well as to identify which transistors contribute the most noise. The digital framework, which analyzes how well circuits function in the presence of significant variations in transistor properties, was used to estimate how fast a circuit can produce an output (referred to as output count rate). In addition, an algorithm was developed and used to estimate the minimum pixel pitch that could be achieved for the pixel circuits of the current prototypes. The simulation frameworks predict that the analog component of the PCA prototypes could have energy resolution as low as 8.9% full width at half maximum (FWHM) at 70 keV; and the digital components should work well even in the presence of significant thin-film transistor (TFT) variations, with the fastest component having output count rates as high as 3 MHz. Finally, based on conceivable improvements in the underlying fabrication process, the algorithm predicts that the 1 mm pitch of the current PCA prototypes could be reduced significantly, potentially to between ~240 and 290 μm. PMID:26878107

  2. Extraction of correlated count rates using various gate generation techniques: Part I theory

    NASA Astrophysics Data System (ADS)

    Croft, S.; Henzlova, D.; Hauck, D. K.

    2012-11-01

    This paper presents an overview of different gate generation techniques that can be used to extract correlated counting rates from neutron pulse trains in the context of Passive Neutron Multiplicity Counting (PNMC). PNMC based on shift register pulse train time autocorrelation analyzers is an important Non-Destructive Assay (NDA) method used in the quantification of plutonium and other spontaneously fissile materials across the nuclear fuel cycle. Traditionally PNMC employs signal-triggered gate generation followed by a random gate, separated from the trigger pulse by a long delay, to extract the totals rate (gross or singles), the pairs (coincidences or doubles) rate, and the triplets (or triples) rate of correlated neutron pulse trains. In this paper we provide expressions for singles, doubles and triples rates using the information available in both, the random and signal-triggered gates (traditional shift register analysis), in the randomly triggered gates only, and introduce a third approach to extract the correlated rates using signal-triggered gates only. In addition, we expand the formalism for randomly triggered gate generation to include Fast Accidental Sampling (FAS) and consecutive gate generation.

  3. Performance analysis of two high actuator count MEMS deformable mirrors

    NASA Astrophysics Data System (ADS)

    Ryan, Peter J.; Cornelissen, Steven A.; Lam, Charlie V.; Bierden, Paul A.

    2013-03-01

    Two new MEMS deformable mirrors have been designed and fabricated, one having a continuous facesheet with an active aperture of 20mm and 2040 actuators and the other, a similarly sized segmented tip tilt piston DM containing 1021 elements and 3063 actuators. The surface figures, electro mechanical performances, and actuator yield of these devices, with statistical information, are reported here. The statistical distributions of these measurements directly illustrate the surface variance of Boston Micromachines deformable mirrors. Measurements of the surface figure were also performed with the elements at different actuation states. Also presented here are deviations of the surface figure under actuation versus at its rest state, the electromechanical distribution, and a dynamic analysis.

  4. A physics investigation of deadtime losses in neutron counting at low rates with Cf252

    SciTech Connect

    Evans, Louise G; Croft, Stephen

    2009-01-01

    {sup 252}Cf spontaneous fission sources are used for the characterization of neutron counters and the determination of calibration parameters; including both neutron coincidence counting (NCC) and neutron multiplicity deadtime (DT) parameters. Even at low event rates, temporally-correlated neutron counting using {sup 252}Cf suffers a deadtime effect. Meaning that in contrast to counting a random neutron source (e.g. AmLi to a close approximation), DT losses do not vanish in the low rate limit. This is because neutrons are emitted from spontaneous fission events in time-correlated 'bursts', and are detected over a short period commensurate with their lifetime in the detector (characterized by the system die-away time, {tau}). Thus, even when detected neutron events from different spontaneous fissions are unlikely to overlap in time, neutron events within the detected 'burst' are subject to intrinsic DT losses. Intrinsic DT losses for dilute Pu will be lower since the multiplicity distribution is softer, but real items also experience self-multiplication which can increase the 'size' of the bursts. Traditional NCC DT correction methods do not include the intrinsic (within burst) losses. We have proposed new forms of the traditional NCC Singles and Doubles DT correction factors. In this work, we apply Monte Carlo neutron pulse train analysis to investigate the functional form of the deadtime correction factors for an updating deadtime. Modeling is based on a high efficiency {sup 3}He neutron counter with short die-away time, representing an ideal {sup 3}He based detection system. The physics of dead time losses at low rates is explored and presented. It is observed that new forms are applicable and offer more accurate correction than the traditional forms.

  5. Extraction of correlated count rates using various gate generation techniques: Part II Experiment

    NASA Astrophysics Data System (ADS)

    Henzlova, D.; Croft, S.; Menlove, H. O.; Swinhoe, M. T.

    2012-11-01

    This paper presents an experimental comparison of different neutron pulse train analysis methods developed to extract correlated count rates from the detected neutron arrival times. This work comprises a sequel to the previous paper (Part I Theory) [1], where the complete formalism of different analysis methods was presented. In the current paper, the signal triggered inspection (STI), randomly triggered inspection (RTI) and MIXED techniques (implemented in current shift register hardware) are compared using list mode data acquired from series of 252Cf sources. In addition, three techniques of randomly triggered inspection are investigated: gates generated at fixed clock frequency, i.e., consecutive (non-overlapping) gates and overlapping gates (known as fast accidentals sampling (FAS)), as well as gates generated after a long delay following each trigger pulse (delayed-signal gates). The average correlated count rates (singles (S), doubles (D) and triples (T)) are extracted using the STI, RTI and MIXED analysis techniques and compared to demonstrate their equivalence. In addition, an influence of different gate generation and pulse train analysis techniques on the precision of the measured S, D and T rates is investigated.

  6. Effects, determination, and correction of count rate nonlinearity in multi-channel analog electron detectors

    SciTech Connect

    Reber, T. J.; Plumb, N. C.; Waugh, J. A.; Dessau, D. S.

    2014-04-15

    Detector counting rate nonlinearity, though a known problem, is commonly ignored in the analysis of angle resolved photoemission spectroscopy where modern multichannel electron detection schemes using analog intensity scales are used. We focus on a nearly ubiquitous “inverse saturation” nonlinearity that makes the spectra falsely sharp and beautiful. These artificially enhanced spectra limit accurate quantitative analysis of the data, leading to mistaken spectral weights, Fermi energies, and peak widths. We present a method to rapidly detect and correct for this nonlinearity. This algorithm could be applicable for a wide range of nonlinear systems, beyond photoemission spectroscopy.

  7. Study of the counting rate capability of MRPC detectors built with soda lime glass

    NASA Astrophysics Data System (ADS)

    Forster, R.; Margoto Rodríguez, O.; Park, W.; Rodríguez Rodríguez, A.; Williams, M. C. S.; Zichichi, A.; Zuyeuski, R.

    2016-09-01

    We report the results of three MRPC detectors built with soda lime glass and tested in the T10 beam line at CERN. The detectors consist of a stack of 280 μm thick glass sheets with 6 gaps of 220 μm . We built two identical MRPCs, except one had the edges of glass treated with resistive paint. A third detector was built with one HV electrode painted as strips. The detectors' efficiency and time resolution were studied at different particle flux in a pulsed beam environment. The results do not show any improvement with the painted edge technique at higher particle flux. We heated the MRPCs up to 40 °C to evaluate the influence of temperature in the rate capability. Results from this warming has indicated an improvement on the rate capability. The dark count rates show a significant dependence with the temperature.

  8. Knowledge Workers' Perceptions of Performance Ratings

    ERIC Educational Resources Information Center

    Smith, Alan D.; Rupp, William T.

    2004-01-01

    One major purpose of performance appraisals is to determine individual merit, especially where pay for performance systems are employed. Based upon expectancy theory, high performance ratings should entail high merit increases while low performance ratings result in low merit increases. However, it appears that decoupling performance ratings and…

  9. [Usefulness of Determining Acquisition Time by True Count Rate Measurement Method for Delivery 18F-FDG PET/CT].

    PubMed

    Miura, Shota; Odashima, Satoshi

    2016-03-01

    A stable quality of delivery 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) requires suitable acquisition time, which can be obtained from an accurate true count of 18F-FDG. However, the true count is influenced by body mass index (BMI) and attenuation of 18F-FDG. In order to remove these influences, we have developed a new method (actual measurement method) to measure the actual true count rate based on sub-pubic thigh, which allows us to calculate a suitable acquisition time. In this study, we aimed to verify the acquisition count through our new method in terms of two categories: (1) the accuracy of acquisition count and (2) evaluation of clinical images using physical index. Our actual measurement method was designed to obtain suitable acquisition time through the following procedure. A true count rate of sub-pubic thigh was measured through detector of PET, and used as a standard true count rate. Finally, the obtained standard count rate was processed to acquisition time. This method was retrospectively applied to 150 patients, receiving 18F-FDG administration from 109.7 to 336.8 MBq, and whose body weight ranged from 37 to 95.4 kg. The accuracy of true count was evaluated by comparing relationships of true count, relative to BMI or to administered dose of 18F-FDG. The PET/CT images obtained by our actual measurement method were assessed using physical index. Our new method resulted in accurate true count, which was not influenced by either BMI or administered dose of 18F-FDG, as well as satisfied PET/CT images with recommended criteria of physical index in all patients. PMID:27000670

  10. Linking Reproduction and Survival Can Improve Model Estimates of Vital Rates Derived from Limited Time-Series Counts of Pinnipeds and Other Species

    PubMed Central

    Battaile, Brian C.; Trites, Andrew W.

    2013-01-01

    We propose a method to model the physiological link between somatic survival and reproductive output that reduces the number of parameters that need to be estimated by models designed to determine combinations of birth and death rates that produce historic counts of animal populations. We applied our Reproduction and Somatic Survival Linked (RSSL) method to the population counts of three species of North Pacific pinnipeds (harbor seals, Phoca vitulina richardii (Gray, 1864); northern fur seals, Callorhinus ursinus (L., 1758); and Steller sea lions, Eumetopias jubatus (Schreber, 1776))—and found our model outperformed traditional models when fitting vital rates to common types of limited datasets, such as those from counts of pups and adults. However, our model did not perform as well when these basic counts of animals were augmented with additional observations of ratios of juveniles to total non-pups. In this case, the failure of the ratios to improve model performance may indicate that the relationship between survival and reproduction is redefined or disassociated as populations change over time or that the ratio of juveniles to total non-pups is not a meaningful index of vital rates. Overall, our RSSL models show advantages to linking survival and reproduction within models to estimate the vital rates of pinnipeds and other species that have limited time-series of counts. PMID:24324541

  11. Keeping Count of All and Losing Count of a Few: The Construction of the High School Dropout Rate

    ERIC Educational Resources Information Center

    Henry, Shana Elizabeth

    2012-01-01

    The quality of the construction of the high school dropout rate is the policy issue investigated in this dissertation. This qualitative dissertation explores the constructs necessary to create a high school dropout rate and seeks to unearth complexities in the construction of the high school dropout rate. Every single year, approximately 1.2…

  12. Low noise, free running, high rate photon counting for space communication and ranging

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Krainak, Michael A.; Yang, Guangning; Sun, Xiaoli; Merritt, Scott

    2016-05-01

    communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies (>50%) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their space communication and ranging performances using both the 2 detected photon threshold and coincidence methods.

  13. The performance of photon counting imaging with a Geiger mode silicon avalanche photodiode

    NASA Astrophysics Data System (ADS)

    Qu, Hui-Ming; Zhang, Yi-Fan; Ji, Zhong-Jie; Chen, Qian

    2013-10-01

    In principle, photon counting imaging can detect a photon. With the development of low-level-light image intensifier techniques and low-level-light detection devices, photon counting imaging can now detect photon images under extremely low illumination. Based on a Geiger mode silicon avalanche photodiode single photon counter, an experimental system for photon counting imaging was built through two-dimensional scanning of a SPAD (single photon avalanche diode) detector. The feasibility of the imaging platform was validated experimentally. Two images with different characteristics, namely, the USAF 1951 resolution test panel and the image of Lena, were chosen to evaluate the imaging performance of the experimental system. The results were compared and analysed. The imaging properties under various illumination and scanning steps were studied. The lowest illumination limit of the SPAD photon counting imaging was determined.

  14. High Broadband Spectral Resolving Transition-Edge Sensors for High Count-Rate Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Smith, Stephen

    2011-01-01

    We are developing arrays of transition-edge sensor (TES) X-ray detectors optimized for high count-rate solar astronomy applications where characterizing the high velocity motions of X-ray jets in solar flares is of particular interest. These devices are fabricated on thick Si substrates and consist of 35x35micron^2 TESs with 4.5micron thick, 60micron pitch, electroplated absorbers. We have tested devices fabricated with different geometric stem contact areas with the TES and surrounding substrate area, which allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between the stem contact area and a non-Gaussian broadening in the spectral line shape consistent with athermal phonon loss. When the contact area is minimized we have obtained remarkable board-band spectral resolving capabilities of 1.3 plus or minus 0.leV at an energy of 1.5 keV, 1.6 plus or minus 0.1 eV at 5.9 keV and 2.0 plus or minus 0.1 eV at 8 keV. This, coupled with a capability of accommodating 100's of counts per second per pixel makes these devices an exciting prospect of future x-ray astronomy applications.

  15. Low-dose performance of a whole-body research photon-counting CT scanner

    NASA Astrophysics Data System (ADS)

    Yu, Zhicong; Leng, Shuai; Kappler, Steffen; Hahn, Katharina; Li, Zhoubo; Halaweish, Ahmed F.; Henning, Andre; Ritman, Erik L.; McCollough, Cynthia H.

    2016-04-01

    Photon-counting CT (PCCT) is an emerging technique that may bring new possibilities to clinical practice. Compared to conventional CT, PCCT is able to exclude electronic noise that may severely impair image quality at low photon counts. This work focused on assessing the low-dose performance of a whole-body research PCCT scanner consisting of two subsystems, one equipped with an energy-integrating detector, and the other with a photon-counting detector. Evaluation of the low-dose performance of the research PCCT scanner was achieved by comparing the noise performance of the two subsystems, with an emphasis on examining the impact of electronic noise on image quality in low-dose situations.

  16. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Rating performance. 430.208 Section 430... Rating performance. (a) As soon as practicable after the end of the appraisal period, a written, or otherwise recorded, rating of record shall be given to each employee. (1) A rating of record shall be...

  17. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Rating performance. 430.208 Section 430... Rating performance. (a) As soon as practicable after the end of the appraisal period, a written, or otherwise recorded, rating of record shall be given to each employee. (1) A rating of record shall be...

  18. In Orbit Performance of Si Avalanche Photodiode Single Photon Counting Modules in the Geoscience Laser Altimeter System on ICESat

    NASA Technical Reports Server (NTRS)

    Sun, X.; Jester, P. L.; Palm, S. P.; Abshire, J. B.; Spinhime, J. D.; Krainak, M. A.

    2006-01-01

    Si avalanche photodiode (APD) single photon counting modules (SPCMs) are used in the Geoscience Laser Altimeter System (GLAS) on Ice, Cloud, anti land Elevation Satellite (ICESat), currently in orbit measuring Earth surface elevation and atmosphere backscattering. These SPCMs are used to measure cloud and aerosol backscatterings to the GLAS laser light at 532-nm wavelength with 60-70% quantum efficiencies and up to 15 millions/s maximum count rates. The performance of the SPCMs has been closely monitored since ICESat launch on January 12, 2003. There has been no measurable change in the quantum efficiency, as indicated by the average photon count rates in response to the background light from the sunlit earth. The linearity and the afterpulsing seen from the cloud and surface backscatterings profiles have been the same as those during ground testing. The detector dark count rates monitored while the spacecraft was in the dark side of the globe have increased almost linearly at about 60 counts/s per day due to space radiation damage. The radiation damage appeared to be independent of the device temperature and power states. There was also an abrupt increase in radiation damage during the solar storm in 28-30 October 2003. The observed radiation damage is a factor of two to three lower than the expected and sufficiently low to provide useful atmosphere backscattering measurements through the end of the ICESat mission. To date, these SPCMs have been in orbit for more than three years. The accumulated operating time to date has reached 290 days (7000 hours). These SPCMs have provided unprecedented receiver sensitivity and dynamic range in ICESat atmosphere backscattering measurements.

  19. Development of a high-count-rate neutron detector with position sensitivity and high efficiency

    SciTech Connect

    Nelson, R.; Sandoval, J.

    1996-10-01

    While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled {sup 3}He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source.

  20. 5 CFR 430.308 - Rating performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Rating performance. 430.308 Section 430.308 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary...

  1. 5 CFR 430.308 - Rating performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Rating performance. 430.308 Section 430.308 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary...

  2. 5 CFR 430.308 - Rating performance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Rating performance. 430.308 Section 430.308 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary...

  3. 5 CFR 430.308 - Rating performance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Rating performance. 430.308 Section 430.308 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary...

  4. 5 CFR 430.308 - Rating performance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Rating performance. 430.308 Section 430.308 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary...

  5. Every Student Counts: The Role of Federal Policy in Improving Graduation Rate Accountability. Policy Brief

    ERIC Educational Resources Information Center

    Richmond, Eric

    2009-01-01

    As the poor performance of U.S. high schools has been acknowledged and come to the forefront of education policy debates over the past several years, so too has a recognition of the need to improve graduation rate calculations and accountability for increasing those rates. A range of state, national, and federal efforts have been launched toward…

  6. Cell counting.

    PubMed

    Phelan, M C; Lawler, G

    2001-05-01

    This unit presents protocols for counting cells using either a hemacytometer or electronically using a Coulter counter. Cell counting with a hemacytometer permits effective discrimination of live from dead cells using trypan blue exclusion. In addition, the procedure is less subject to errors arising from cell clumping or size heterogeneity. Counting cells is more quickly and easily performed using an electronic counter, but live-dead discrimination is unreliable. Cell populations containing large numbers of dead cells and/or cell clumps are difficult to count accurately. In addition, electronic counting requires resetting of the instrument for cell populations of different sizes; heterogeneous populations can give rise to inaccurate counts, and resting and activated cells may require counting at separate settings. In general, electronic cell counting is best performed on fresh peripheral blood cells. PMID:18770655

  7. Monitoring dry period intramammary infection incidence and elimination rates using somatic cell count measurements.

    PubMed

    Dufour, S; Dohoo, I R

    2012-12-01

    The objective of the study was to evaluate the predictive ability of the herd dry period (DP) intramammary infection (IMI) incidence and elimination rates derived from predry and postcalving somatic cell count (SCC) measurements [quarter-level SCC and dairy herd improvement (DHI) composite-level SCC] for monitoring the herd DP IMI incidence and elimination rates. A cohort of 91 Canadian dairy herds was followed from 2007 to 2008. In each herd, a sample of 15 cows was selected each year, and a series of 2 predry and 2 postcalving quarter milk samples were collected. Routine milk bacteriological culture was conducted to identify IMI, SCC was measured on the quarter milk samples, and composite SCC of the last predry and first postcalving DHI tests were obtained. Mastitis pathogens were grouped into 3 categories: major pathogens, minor pathogens, and any pathogens. For each herd, DP bacteriological culture-derived IMI incidence and elimination rates were computed using quarter milk culture data. Similarly, SCC-derived herd incidence and elimination rates were computed using quarter and DHI composite-level SCC measurements and using various SCC thresholds to define new and eliminated IMI. Linear regression was used to compare herd quarter-level and composite-level SCC-derived herd incidence and elimination with DP bacteriological culture-derived IMI incidence and elimination. Herd DP incidences computed by using quarter-level SCC, and with most of the SCC thresholds tested, were significant predictors of the DP major, minor, and any IMI incidences (F-test; P≤0.05). The highest coefficients of determination (R(2)) were obtained with thresholds of 200,000 (R(2): 12%) and 50,000 cells/mL (R(2): 25%) for predicting major and minor IMI, respectively. When using composite DHI SCC measurements, however, substantial losses of predictive power were seen for minor and any IMI incidences compared with quarter-level SCC. For DP major IMI incidence, composite SCC yielded similar

  8. Optimization of statistical methods for HpGe gamma-ray spectrometer used in wide count rate ranges

    NASA Astrophysics Data System (ADS)

    Gervino, G.; Mana, G.; Palmisano, C.

    2016-07-01

    The need to perform γ-ray measurements with HpGe detectors is a common technique in many fields such as nuclear physics, radiochemistry, nuclear medicine and neutron activation analysis. The use of HpGe detectors is chosen in situations where isotope identification is needed because of their excellent resolution. Our challenge is to obtain the "best" spectroscopy data possible in every measurement situation. "Best" is a combination of statistical (number of counts) and spectral quality (peak, width and position) over a wide range of counting rates. In this framework, we applied Bayesian methods and the Ellipsoidal Nested Sampling (a multidimensional integration technique) to study the most likely distribution for the shape of HpGe spectra. In treating these experiments, the prior information suggests to model the likelihood function with a product of Poisson distributions. We present the efforts that have been done in order to optimize the statistical methods to HpGe detector outputs with the aim to evaluate to a better order of precision the detector efficiency, the absolute measured activity and the spectra background. Reaching a more precise knowledge of statistical and systematic uncertainties for the measured physical observables is the final goal of this research project.

  9. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....208 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Performance Appraisal for General Schedule, Prevailing Rate, and Certain Other Employees § 430.208... reviewed and approved by a higher level management official. (f) The rating of record or performance...

  10. Field Assessment of Enclosed Cab Filtration System Performance Using Particle Counting Measurements

    PubMed Central

    Organiscak, John A.; Cecala, Andrew B.; Noll, James D.

    2015-01-01

    Enclosed cab filtration systems are typically used on mobile mining equipment to reduce miners’ exposure to airborne dust generated during mining operations. The National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently worked with a mining equipment manufacturer to examine a new cab filtration system design for underground industrial minerals equipment. This cab filtration system uses a combination of three particulate filters to reduce equipment operators’ exposure to dust and diesel particulates present in underground industrial mineral mines. NIOSH initially examined this cab filtration system using a two-instrument particle counting method at the equipment company’s manufacturing shop facility to assess several alternative filters. This cab filtration system design was further studied on several pieces of equipment during a two- to seven-month period at two underground limestone mines. The two-instrument particle counting method was used outside the underground mine at the end of the production shifts to regularly test the cabs’ long-term protection factor performance with particulates present in the ambient air. This particle counting method showed that three of the four cabs achieved protection factors greater than 1,000 during the field studies. The fourth cab did not perform at this level because it had a damaged filter in the system. The particle counting measurements of submicron particles present in the ambient air were shown to be a timely and useful quantification method in assessing cab performance during these field studies. PMID:23915268

  11. Modeling the performance of a photon counting x-ray detector for CT: Energy response and pulse pileup effects

    SciTech Connect

    Taguchi, Katsuyuki; Zhang, Mengxi; Frey, Eric C.; Wang Xiaolan; Iwanczyk, Jan S.; Nygard, Einar; Hartsough, Neal E.; Tsui, Benjamin M. W.; Barber, William C.

    2011-02-15

    Purpose: Recently, photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed for potential use in clinical computed tomography (CT) scanners. These PCXDs have great potential to improve the quality of CT images due to the absence of electronic noise and weights applied to the counts and the additional spectral information. With high count rates encountered in clinical CT, however, coincident photons are recorded as one event with a higher or lower energy due to the finite speed of the PCXD. This phenomenon is called a ''pulse pileup event'' and results in both a loss of counts (called ''deadtime losses'') and distortion of the recorded energy spectrum. Even though the performance of PCXDs is being improved, it is essential to develop algorithmic methods based on accurate models of the properties of detectors to compensate for these effects. To date, only one PCXD (model DXMCT-1, DxRay, Inc., Northridge, CA) has been used for clinical CT studies. The aim of that study was to evaluate the agreement between data measured by DXMCT-1 and those predicted by analytical models for the energy response, the deadtime losses, and the distorted recorded spectrum caused by pulse pileup effects. Methods: An energy calibration was performed using {sup 99m}Tc (140 keV), {sup 57}Co (122 keV), and an x-ray beam obtained with four x-ray tube voltages (35, 50, 65, and 80 kVp). The DXMCT-1 was placed 150 mm from the x-ray focal spot; the count rates and the spectra were recorded at various tube current values from 10 to 500 {mu}A for a tube voltage of 80 kVp. Using these measurements, for each pulse height comparator we estimated three parameters describing the photon energy-pulse height curve, the detector deadtime {tau}, a coefficient k that relates the x-ray tube current I to an incident count rate a by a=kxI, and the incident spectrum. The mean pulse shape of all comparators was acquired in a separate study and was used in the model to

  12. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    PubMed Central

    Cho, Hyo-Min; Barber, William C.; Ding, Huanjun; Iwanczyk, Jan S.; Molloi, Sabee

    2014-01-01

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A109Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm2) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The energy resolution

  13. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    SciTech Connect

    Cho, Hyo-Min; Ding, Huanjun; Molloi, Sabee; Barber, William C.; Iwanczyk, Jan S.

    2014-09-15

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A{sup 109}Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm{sup 2}) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The energy

  14. Modeling the Relationship Between Neutron Counting Rates and Sunspot Numbers Using the Hysteresis Effect

    NASA Astrophysics Data System (ADS)

    Inceoglu, F.; Knudsen, M. F.; Karoff, C.; Olsen, J.

    2014-04-01

    Several studies show that temporal variations in the Galactic cosmic ray (GCR) intensity display a distinct 11-year periodicity due to solar modulation of the galactic cosmic rays in the heliosphere. The 11-year periodicity of GCRs is inversely proportional to, but out of phase with, the 11-year solar cycle, implying that there is a time lag between actual solar cycle and the GCR intensity, which is known as the hysteresis effect. In this study, we use the hysteresis effect to model the relationship between neutron counting rates (NCRs), an indicator of the GCR intensity, and sunspot numbers (SSNs) over the period that covers the last four solar cycles (20, 21, 22, and 23). Both linear and ellipse models were applied to SSNs during odd and even cycles in order to calculate temporal variations of NCRs. We find that ellipse modeling provides higher correlation coefficients for odd cycles compared to linear models, e.g. 0.97, 0.97, 0.92, and 0.97 compared to 0.69, 0.72, 0.53, and 0.68 for data from McMurdo, Swarthmore, South Pole, and Thule neutron monitors, respectively, during solar cycle 21 with overall improvement of 31 % for odd cycles. When combined to a continuous model, the better correlation observed for the odd cycles increases the overall correlation between observed and modeled NCRs. The new empirical model therefore provides a better representation of the relationship between NCRs and SSNs. A major goal of the ongoing research is to use the new non-linear empirical model to reconstruct SSNs on annual time scales prior to 1610, where we do not have observational records of SSNs, based on changes in NCRs reconstructed from 10Be in ice cores.

  15. Performance of analytical methods for overdispersed counts in cluster randomized trials: sample size, degree of clustering and imbalance.

    PubMed

    Durán Pacheco, Gonzalo; Hattendorf, Jan; Colford, John M; Mäusezahl, Daniel; Smith, Thomas

    2009-10-30

    Many different methods have been proposed for the analysis of cluster randomized trials (CRTs) over the last 30 years. However, the evaluation of methods on overdispersed count data has been based mostly on the comparison of results using empiric data; i.e. when the true model parameters are not known. In this study, we assess via simulation the performance of five methods for the analysis of counts in situations similar to real community-intervention trials. We used the negative binomial distribution to simulate overdispersed counts of CRTs with two study arms, allowing the period of time under observation to vary among individuals. We assessed different sample sizes, degrees of clustering and degrees of cluster-size imbalance. The compared methods are: (i) the two-sample t-test of cluster-level rates, (ii) generalized estimating equations (GEE) with empirical covariance estimators, (iii) GEE with model-based covariance estimators, (iv) generalized linear mixed models (GLMM) and (v) Bayesian hierarchical models (Bayes-HM). Variation in sample size and clustering led to differences between the methods in terms of coverage, significance, power and random-effects estimation. GLMM and Bayes-HM performed better in general with Bayes-HM producing less dispersed results for random-effects estimates although upward biased when clustering was low. GEE showed higher power but anticonservative coverage and elevated type I error rates. Imbalance affected the overall performance of the cluster-level t-test and the GEE's coverage in small samples. Important effects arising from accounting for overdispersion are illustrated through the analysis of a community-intervention trial on Solar Water Disinfection in rural Bolivia. PMID:19672840

  16. High Count-Rate Studies of Small-Pitch Transition-Edge Sensor X-ray Microcalorimeters

    NASA Astrophysics Data System (ADS)

    Lee, S. J.; Bandler, S. R.; Busch, S. E.; Adams, J. S.; Chervenak, J. A.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porst, J.-P.; Porter, F. S.; Sadleir, J. E.; Smith, S. J.; Wassel, E. J.

    2014-08-01

    We are developing kilo-pixel arrays of small-pitch transition-edge sensors for high spectral-resolving, high count-rate applications in astrophysics and solar physics measurements. We have fabricated and tested pixels that are m in size on a silicon substrate with an X-ray flux of counts per second (cps) per pixel. The X-ray pulses were recorded and analyzed in various ways to obtain high throughput with good energy resolution. We have demonstrated 2.3 eV FWHM resolution with 99.6 % throughput for a 6-keV X-ray flux of 100 cps.

  17. Persistent Ratee Contaminants in Performance Appraisal.

    ERIC Educational Resources Information Center

    Van Fleet, David D.; Chamberlain, Howard

    The hypothesis that conventional approaches to evaluating contaminants in performance appraisal overlook important individual ratee effects was examined. A rating form was developed that consisted of the following dimensions and behaviors: warmth; guided discourse or indirect teaching methods; control of subject matter; enthusiasm and reinforcing;…

  18. Performance Evaluation of Whole Body Counting Facilities in the Marshall Islands (2002-2005)

    SciTech Connect

    Kehl, S R; Hamilton, T; Jue, T; Hickman, D

    2007-04-03

    The United States Department of Energy (U.S. DOE) has recently implemented a series of strategic initiatives to address long-term radiological surveillance needs at former U.S. nuclear test sites in the Marshall Islands (https://eed.llnl.gov/mi/). Local atoll governments have been actively engaged in developing shared responsibilities for protecting the health and safety of resettled and resettling population at risk from exposure to elevated levels of residual fallout contamination in the environment. Under the program, whole body counting facilities have been established at three locations in the Marshall Islands. These facilities are operated and maintained by Marshallese technicians with scientists from the Lawrence Livermore National Laboratory (LLNL) providing technical support services including data quality assurance and performance testing. We have also established a mirror whole body counting facility at the Lawrence Livermore National Laboratory as a technician training center. The LLNL facility also allows program managers to develop quality assurance and operational procedures, and test equipment and corrective actions prior to deployment at remote stations in the Marshall Islands. This document summarizes the results of external performance evaluation exercises conducted at each of the facilities (2002-2005) under the umbrella of the Oak Ridge National Laboratory Intercomparison Studies Program (ISP). The ISP was specifically designed to meet intercomparison requirements of the United States (U.S.) Department of Energy Laboratory Accreditation Program (DOELAP). In this way, the Marshall Islands Radiological Surveillance Program has attempted to establish quality assurance measures in whole body counting that are consistent with standard requirements used to monitor DOE workers in the United States. Based on ANSI N13.30, the acceptable performance criteria for relative measurement bias and precision for radiobioassay service laboratory quality control

  19. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators

    NASA Astrophysics Data System (ADS)

    Surti, S.; Karp, J. S.

    2005-12-01

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr3), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been used to study the effect on scanner deadtime and pulse pileup at high activity levels due to the scintillator stopping power (μ), decay time (τ) and energy resolution. Simulations were performed for a uniform 20 cm diameter × 70 cm long cylinder (NEMA NU2-2001 standard) in a whole-body scanner with an 85 cm ring diameter and a 25 cm axial field-of-view. Our results for these whole-body scanners demonstrate the potential of a pixelated Anger-logic detector and the relationship of its performance with the scanner NEC rate. Faster signal decay and short coincidence timing window lead to a reduction in deadtime and randoms fraction in the LaBr3 and LSO scanners compared to GSO. The excellent energy resolution of LaBr3 leads to the lowest scatter fraction for all scanners and helps compensate for reduced sensitivity compared to the GSO and LSO scanners, leading to the highest NEC values at high activity concentrations. The LSO scanner has the highest sensitivity of all the scanner designs investigated here, therefore leading to the highest peak NEC value but at a lower activity concentration than that of LaBr3.

  20. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators.

    PubMed

    Surti, S; Karp, J S

    2005-12-01

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr(3)), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been used to study the effect on scanner deadtime and pulse pileup at high activity levels due to the scintillator stopping power (mu), decay time (tau) and energy resolution. Simulations were performed for a uniform 20 cm diameter x 70 cm long cylinder (NEMA NU2-2001 standard) in a whole-body scanner with an 85 cm ring diameter and a 25 cm axial field-of-view. Our results for these whole-body scanners demonstrate the potential of a pixelated Anger-logic detector and the relationship of its performance with the scanner NEC rate. Faster signal decay and short coincidence timing window lead to a reduction in deadtime and randoms fraction in the LaBr(3) and LSO scanners compared to GSO. The excellent energy resolution of LaBr(3) leads to the lowest scatter fraction for all scanners and helps compensate for reduced sensitivity compared to the GSO and LSO scanners, leading to the highest NEC values at high activity concentrations. The LSO scanner has the highest sensitivity of all the scanner designs investigated here, therefore leading to the highest peak NEC value but at a lower activity concentration than that of LaBr(3). PMID:16306662

  1. Performance of in-pixel circuits for photon counting arrays (PCAs) based on polycrystalline silicon TFTs

    NASA Astrophysics Data System (ADS)

    Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua; Street, Robert A.; Lu, Jeng Ping

    2016-03-01

    Photon counting arrays (PCAs), defined as pixelated imagers which measure the absorbed energy of x-ray photons individually and record this information digitally, are of increasing clinical interest. A number of PCA prototypes with a 1 mm pixel-to-pixel pitch have recently been fabricated with polycrystalline silicon (poly-Si)—a thin-film technology capable of creating monolithic imagers of a size commensurate with human anatomy. In this study, analog and digital simulation frameworks were developed to provide insight into the influence of individual poly-Si transistors on pixel circuit performance—information that is not readily available through empirical means. The simulation frameworks were used to characterize the circuit designs employed in the prototypes. The analog framework, which determines the noise produced by individual transistors, was used to estimate energy resolution, as well as to identify which transistors contribute the most noise. The digital framework, which analyzes how well circuits function in the presence of significant variations in transistor properties, was used to estimate how fast a circuit can produce an output (referred to as output count rate). In addition, an algorithm was developed and used to estimate the minimum pixel pitch that could be achieved for the pixel circuits of the current prototypes. The simulation frameworks predict that the analog component of the PCA prototypes could have energy resolution as low as 8.9% full width at half maximum (FWHM) at 70 keV; and the digital components should work well even in the presence of significant thin-film transistor (TFT) variations, with the fastest component having output count rates as high as 3 MHz. Finally, based on conceivable improvements in the underlying fabrication process, the algorithm predicts that the 1 mm pitch of the current PCA prototypes could be reduced significantly, potentially to between ~240 and 290 μm.

  2. Alternative Optimizations of X-ray TES Arrays: Soft X-rays, High Count Rates, and Mixed-Pixel Arrays

    NASA Technical Reports Server (NTRS)

    Kilbourne, C. A.; Bandler, S. R.; Brown, A.-D.; Chervenak, J. A.; Figueroa-Feliciano, E.; Finkbeiner, F. M.; Iyomoto, N.; Kelley, R. L.; Porter, F. S.; Smith, S. J.

    2007-01-01

    We are developing arrays of superconducting transition-edge sensors (TES) for imaging spectroscopy telescopes such as the XMS on Constellation-X. While our primary focus has been on arrays that meet the XMS requirements (of which, foremost, is an energy resolution of 2.5 eV at 6 keV and a bandpass from approx. 0.3 keV to 12 keV), we have also investigated other optimizations that might be used to extend the XMS capabilities. In one of these optimizations, improved resolution below 1 keV is achieved by reducing the heat capacity. Such pixels can be based on our XMS-style TES's with the separate absorbers omitted. These pixels can added to an array with broadband response either as a separate array or interspersed, depending on other factors that include telescope design and science requirements. In one version of this approach, we have designed and fabricated a composite array of low-energy and broad-band pixels to provide high spectral resolving power over a broader energy bandpass than could be obtained with a single TES design. The array consists of alternating pixels with and without overhanging absorbers. To explore optimizations for higher count rates, we are also optimizing the design and operating temperature of pixels that are coupled to a solid substrate. We will present the performance of these variations and discuss other optimizations that could be used to enhance the XMS or enable other astrophysics experiments.

  3. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-01

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the ‘ring’ artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset.

  4. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events.

    PubMed

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-01

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the 'ring' artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset. PMID:26086713

  5. A compact 7-cell Si-drift detector module for high-count rate X-ray spectroscopy

    PubMed Central

    Hansen, K.; Reckleben, C.; Diehl, I.; Klär, H.

    2015-01-01

    A new Si-drift detector module for fast X-ray spectroscopy experiments was developed and realized. The Peltier-cooled module comprises a sensor with 7 × 7-mm2 active area, an integrated circuit for amplification, shaping and detection, storage, and derandomized readout of signal pulses in parallel, and amplifiers for line driving. The compactness and hexagonal shape of the module with a wrench size of 16mm allow very short distances to the specimen and multi-module arrangements. The power dissipation is 186mW. At a shaper peaking time of 190 ns and an integration time of 450 ns an electronic rms noise of ~11 electrons was achieved. When operated at 7 °C, FWHM line widths around 260 and 460 eV (Cu-Kα) were obtained at low rates and at sum-count rates of 1.7 MHz, respectively. The peak shift is below 1% for a broad range of count rates. At 1.7-MHz sum-count rate the throughput loss amounts to 30%. PMID:26366028

  6. Mu-Spec - A High Performance Ultra-Compact Photon Counting spectrometer for Space Submillimeter Astronomy

    NASA Technical Reports Server (NTRS)

    Moseley, H.; Hsieh, W.-T.; Stevenson, T.; Wollack, E.; Brown, A.; Benford, D.; Sadleir; U-Yen, I.; Ehsan, N.; Zmuidzinas, J.; Bradford, M.

    2011-01-01

    We have designed and are testing elements of a fully integrated submillimeter spectrometer based on superconducting microstrip technology. The instrument can offer resolving power R approximately 1500, and its high frequency cutoff is set by the gap of available high performance superconductors. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using planar filter, and detected using photon counting MKID detector. This spectrometer promises to revolutionize submillimeter spectroscopy from space. It replaces instruments with the scale of 1m with a spectrometer on a 10 cm Si wafer. The reduction in mass and volume promises a much higher performance system within available resource in a space mission. We will describe the system and the performance of the components that have been fabricated and tested.

  7. High-voltage integrated active quenching circuit for single photon count rate up to 80 Mcounts/s.

    PubMed

    Acconcia, Giulia; Rech, Ivan; Gulinatti, Angelo; Ghioni, Massimo

    2016-08-01

    Single photon avalanche diodes (SPADs) have been subject to a fast improvement in recent years. In particular, custom technologies specifically developed to fabricate SPAD devices give the designer the freedom to pursue the best detector performance required by applications. A significant breakthrough in this field is represented by the recent introduction of a red enhanced SPAD (RE-SPAD) technology, capable of attaining a good photon detection efficiency in the near infrared range (e.g. 40% at a wavelength of 800 nm) while maintaining a remarkable timing resolution of about 100ps full width at half maximum. Being planar, the RE-SPAD custom technology opened the way to the development of SPAD arrays particularly suited for demanding applications in the field of life sciences. However, to achieve such excellent performance custom SPAD detectors must be operated with an external active quenching circuit (AQC) designed on purpose. Next steps toward the development of compact and practical multichannel systems will require a new generation of monolithically integrated AQC arrays. In this paper we present a new, fully integrated AQC fabricated in a high-voltage 0.18 µm CMOS technology able to provide quenching pulses up to 50 Volts with fast leading and trailing edges. Although specifically designed for optimal operation of RE-SPAD devices, the new AQC is quite versatile: it can be used with any SPAD detector, regardless its fabrication technology, reaching remarkable count rates up to 80 Mcounts/s and generating a photon detection pulse with a timing jitter as low as 119 ps full width at half maximum. The compact design of our circuit has been specifically laid out to make this IC a suitable building block for monolithically integrated AQC arrays. PMID:27505749

  8. [Cognitive dimensions used in rating work performance].

    PubMed

    Yanagizawa, Saori

    2008-12-01

    This study explored the cognitive dimensions used by individuals in judging work performance based on the individual scale methodology of Hayashi, Ohashi, & Hirooka (1983). The participants were fifteen undergraduate students and nine workers. First, the participants described the characteristics of eight high performers and eight low performers whom they had worked with. Second, from these characteristics, they selected twenty characteristics that they considered as determinants in judging whether performers are superior or inferior. Third, using an individual scale consisting of the selected characteristics, they rated sixteen high performers and sixteen low performers. Factor analyses were conducted for each participant's ratings on the individual scale. The results suggested that three or four dimensions were generally used in judging performers, although there were individual differences in the number of dimensions used. Undergraduate students judged performers using more cognitive dimensions than workers did. The contents of the cognitive dimensions were relevant to technical skill, work attitude, cognitive ability, motivation, interpersonal competence, leadership, and personality. Undergraduate students used fewer cognitive ability dimensions and more personality dimensions than workers used. PMID:19172909

  9. A Six-Year Study on the Changes in Airborne Pollen Counts and Skin Positivity Rates in Korea: 2008–2013

    PubMed Central

    Park, Hye Jung; Lee, Jae-Hyun; Park, Kyung Hee; Kim, Kyu Rang; Han, Mae Ja; Choe, Hosoeng

    2016-01-01

    Purpose The occurrence of pollen allergy is subject to exposure to pollen, which shows regional and temporal variations. We evaluated the changes in pollen counts and skin positivity rates for 6 years, and explored the correlation between their annual rates of change. Materials and Methods We assessed the number of pollen grains collected in Seoul, and retrospectively reviewed the results of 4442 skin-prick tests conducted at the Severance Hospital Allergy-Asthma Clinic from January 1, 2008 to December 31, 2013. Results For 6 years, the mean monthly total pollen count showed two peaks, one in May and the other in September. Pollen count for grasses also showed the same trend. The pollen counts for trees, grasses, and weeds changed annually, but the changes were not significant. The annual skin positivity rates in response to pollen from grasses and weeds increased significantly over the 6 years. Among trees, the skin positivity rates in response to pollen from walnut, popular, elm, and alder significantly increased over the 6 years. Further, there was a significant correlation between the annual rate of change in pollen count and the rate of change in skin positivity rate for oak and hop Japanese. Conclusion The pollen counts and skin positivity rates should be monitored, as they have changed annually. Oak and hop Japanese, which showed a significant correlation with the annual rate of change in pollen count and the rate of change in skin positivity rate over the 6 years may be considered the major allergens in Korea. PMID:26996572

  10. Counting-On, Trading and Partitioning: Effects of Training and Prior Knowledge on Performance on Base-10 Tasks

    ERIC Educational Resources Information Center

    Saxton, Matthew; Cakir, Kadir

    2006-01-01

    Factors affecting performance on base-10 tasks were investigated in a series of four studies with a total of 453 children aged 5-7 years. Training in counting-on was found to enhance child performance on base-10 tasks (Studies 2, 3, and 4), while prior knowledge of counting-on (Study 1), trading (Studies 1 and 3), and partitioning (Studies 1 and…

  11. Rating the energy performance of buildings

    SciTech Connect

    Olofsson, Thomas; Meier, Alan; Lamberts, Roberto

    2004-12-01

    In order to succeed in developing a more sustainable society, buildings will need to be continuously improved. This paper discusses how to rate the energy performance of buildings. A brief review of recent approaches to energy rating is presented. It illustrates that there is no single correct or wrong concept, but one needs to be aware of the relative impact of the strategies. Different strategies of setting energy efficiency standards are discussed and the advantages of the minimum life cycle cost are shown. Indicators for building energy rating based on simulations, aggregated statistics and expert knowledge are discussed and illustrated in order to demonstrate strengths and weaknesses of each approach. In addition, the importance of considering the level of amenities offered is presented. Attributes of a rating procedure based on three elements, flexible enough for recognizing different strategies to achieve energy conservation, is proposed.

  12. The Slope Imaging Multi-Polarization Photon-Counting Lidar: Development and Performance Results

    NASA Technical Reports Server (NTRS)

    Dabney, Phillip

    2010-01-01

    The Slope Imaging Multi-polarization Photon-counting Lidar is an airborne instrument developed to demonstrate laser altimetry measurement methods that will enable more efficient observations of topography and surface properties from space. The instrument was developed through the NASA Earth Science Technology Office Instrument Incubator Program with a focus on cryosphere remote sensing. The SIMPL transmitter is an 11 KHz, 1064 nm, plane-polarized micropulse laser transmitter that is frequency doubled to 532 nm and split into four push-broom beams. The receiver employs single-photon, polarimetric ranging at 532 and 1064 nm using Single Photon Counting Modules in order to achieve simultaneous sampling of surface elevation, slope, roughness and depolarizing scattering properties, the latter used to differentiate surface types. Data acquired over ice-covered Lake Erie in February, 2009 are documenting SIMPL s measurement performance and capabilities, demonstrating differentiation of open water and several ice cover types. ICESat-2 will employ several of the technologies advanced by SIMPL, including micropulse, single photon ranging in a multi-beam, push-broom configuration operating at 532 nm.

  13. Performances of photodiode detectors for top and bottom counting detectors of ISS-CREAM experiment

    NASA Astrophysics Data System (ADS)

    Hyun, H. J.; Anderson, T.; Angelaszek, D.; Baek, S. J.; Copley, M.; Coutu, S.; Han, J. H.; Huh, H. G.; Hwang, Y. S.; Im, S.; Jeon, H. B.; Kah, D. H.; Kang, K. H.; Kim, H. J.; Kim, K. C.; Kwashnak, K.; Lee, J.; Lee, M. H.; Link, J. T.; Lutz, L.; Mitchell, J. W.; Nutter, S.; Ofoha, O.; Park, H.; Park, I. H.; Park, J. M.; Patterson, P.; Seo, E. S.; Wu, J.; Yoon, Y. S.

    2015-07-01

    The Cosmic Ray Energetics and Mass (CREAM) experiment at the International Space Station (ISS) aims to elucidate the source and acceleration mechanisms of high-energy cosmic rays by measuring the energy spectra from protons to iron. The instrument is planned for launch in 2015 at the ISS, and it comprises a silicon charge detector, a carbon target, top and bottom counting detectors, a calorimeter, and a boronated scintillator detector. The top and bottom counting detectors are developed for separating the electrons from the protons, and each of them comprises a plastic scintillator and a 20×20 silicon photodiode array. Each photodiode is 2.3 cm×2.3 cm in size and exhibits good electrical characteristics. The leakage current is measured to be less than 20 nA/cm2 at an operating voltage. The signal-to-noise ratio is measured to be better than 70 using commercial electronics, and the radiation hardness is tested using a proton beam. A signal from the photodiode is amplified by VLSI (very-large-scale integration) charge amp/hold circuits, the VA-TA viking chip. Environmental tests are performed using whole assembled photodiode detectors of a flight version. Herein, we present the characteristics of the developed photodiode along with the results of the environmental tests.

  14. High-performance reconfigurable coincidence counting unit based on a field programmable gate array.

    PubMed

    Park, Byung Kwon; Kim, Yong-Su; Kwon, Osung; Han, Sang-Wook; Moon, Sung

    2015-05-20

    We present a high-performance reconfigurable coincidence counting unit (CCU) using a low-end field programmable gate array (FPGA) and peripheral circuits. Because of the flexibility guaranteed by the FPGA program, we can easily change system parameters, such as internal input delays, coincidence configurations, and the coincidence time window. In spite of a low-cost implementation, the proposed CCU architecture outperforms previous ones in many aspects: it has 8 logic inputs and 4 coincidence outputs that can measure up to eight-fold coincidences. The minimum coincidence time window and the maximum input frequency are 0.47 ns and 163 MHz, respectively. The CCU will be useful in various experimental research areas, including the field of quantum optics and quantum information. PMID:26192507

  15. SWAD: inherent photon counting performance of amorphous selenium multi-well avalanche detector

    NASA Astrophysics Data System (ADS)

    Stavro, Jann; Goldan, Amir H.; Zhao, Wei

    2016-03-01

    Photon counting detectors (PCDs) have the potential to improve x-ray imaging, however they are still hindered by several performance limitations and high production cost. By using amorphous Selenium (a-Se) the cost of PCDs can be significantly reduced compared to crystalline materials and enable large area detector fabrication. To overcome the problem of low carrier mobility and low charge conversion gain in a-Se, we are developing a novel direct conversion a- Se field-Shaping multi-Well Avalanche Detector (SWAD). SWAD circumvents the charge transport limitation by using a Frisch grid built within the readout circuit, reducing charge collection time to ~200 ns. Field shaping permits depth independent avalanche gain in wells, resulting in total conversion gain that is comparable to Si and CdTe. In the present work we investigate the effects of charge sharing and energy loss to understand the inherent photon counting performance for SWAD at x-ray energies used in breast imaging applications (20-50keV). The energy deposition profile for each interacting x-ray was determined with Monte Carlo simulation. For the energy ranges we are interested in, photoelectric interaction dominates, with a k-fluorescence yield of approximately 60%. Using a monoenergetic 45 keV beam incident on a target pixel in 400um of a-Se, our results show that only 20.42 % and 22.4 % of primary interacting photons have kfluorescence emissions which escape the target pixel for 100um and 85um pixel sizes respectively, demonstrating SWAD's potential for high spatial resolution applications.

  16. Performance demonstration of 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme.

    PubMed

    Kulkarni, D B; Anuradha, R; Joseph, Leena; Kulkarni, M S; Tomar, B S

    2016-02-01

    A standardization of (134)Cs and (131)I was carried out in order to demonstrate the performance and applicability of the 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme. The coincidence analyzer, capable of analyzing coincidence between beta and two gamma windows simultaneously, was developed and used for the standardization. The use of this dual coincidence analyzer has reduced the total experimental time by half. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, a 4πβ(PC)-γ coincidence counting system, and the CIEMAT/NIST method are in excellent agreement with each other within uncertainty limits and hence demonstrates its performance for standardization of radionuclides decaying with complex decay scheme. Hence use of this 4πβ(LS)-γ coincidence counting system can be an alternative method suitable to standardize radionuclides with complex decay scheme with acceptable precision. PMID:26678524

  17. Design and performance of a fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system

    NASA Astrophysics Data System (ADS)

    Huang, Genghua; Shu, Rong; Hou, Libing; Li, Ming

    2014-06-01

    Photon counting lidar has an ultra-high sensitivity which can be hundreds even thousands of times higher than the linear detection lidar. It can significantly increase the system's capability of detection rang and imaging density, saving size and power consumings in airborne or space-borne applications. Based on Geiger-mode Si avalanche photodiodes (Si-APD), a prototype photon counting lidar which used 8 APDs coupled with a 1×8-pixel fiber array has been made in June, 2011. The experiments with static objects showed that the photon counting lidar could operate in strong solar background with 0.04 receiving photoelectrons on average. Limited by less counting times in moving platforms, the probability of detection and the 3D imaging density would be lower than that in static platforms. In this paper, a latest fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system is introduced. The correlation range receiver algorithm of photon counting 3D imaging is improved for airborne signal photon events extraction and noise filter. The 3D imaging experiments in the helicopter shows that the false alarm rate is less than 6×10-7, and the correct rate is better than 99.9% with 4 received photoelectrons and 0.7MHz system noise on average.

  18. A Count for Quality: Child Care Center Directors on Rating and Improvement Systems

    ERIC Educational Resources Information Center

    Schulman, Karen; Matthews, Hannah; Blank, Helen; Ewen, Danielle

    2012-01-01

    Quality Rating and Improvement Systems (QRIS)--a strategy to improve families' access to high-quality child care--assess the quality of child care programs, offer incentives and assistance to programs to improve their ratings, and give information to parents about the quality of child care. These systems are operating in a growing number of…

  19. Quality Counts 2005: No Small Change--Targeting Money toward Student Performance

    ERIC Educational Resources Information Center

    Education Week, 2005

    2005-01-01

    "Quality Counts 2005" focuses on the burgeoning efforts to link funding to educational outcomes. This special issue of "Education Week" includes the following articles: (1) Financial Evolution (Lynn Olson); (2) Making Every Dollar Count (Robert C. Johnston); (3) Weighty Decisions (Jeff Archer); (4) Salary Adjustments (Melissa McCabe); (5)…

  20. A New High Channel-Count, High Scan-Rate, Data Acquisition System for the NASA Langley Transonic Dynamics Tunnel

    NASA Technical Reports Server (NTRS)

    Ivanco, Thomas G.; Sekula, Martin K.; Piatak, David J.; Simmons, Scott A.; Babel, Walter C.; Collins, Jesse G.; Ramey, James M.; Heald, Dean M.

    2016-01-01

    A data acquisition system upgrade project, known as AB-DAS, is underway at the NASA Langley Transonic Dynamics Tunnel. AB-DAS will soon serve as the primary data system and will substantially increase the scan-rate capabilities and analog channel count while maintaining other unique aeroelastic and dynamic test capabilities required of the facility. AB-DAS is configurable, adaptable, and enables buffet and aeroacoustic tests by synchronously scanning all analog channels and recording the high scan-rate time history values for each data quantity. AB-DAS is currently available for use as a stand-alone data system with limited capabilities while development continues. This paper describes AB-DAS, the design methodology, and the current features and capabilities. It also outlines the future work and projected capabilities following completion of the data system upgrade project.

  1. Associations between Counting Ability in Preschool and Mathematic Performance in First Grade among a Sample of Ethnically Diverse, Low-Income Children

    ERIC Educational Resources Information Center

    Manfra, Louis; Dinehart, Laura H. B.; Sembiante, Sabrina F.

    2014-01-01

    This study explores the effects of counting objects and reciting numbers in preschool on 1st-grade math performance. Data on 3,125 low-income preschoolers' (4-to 5-year-olds) counting abilities (orally reciting numerals in chronological order and counting blocks) were collected during a fall session (between September 15 and December 15) and…

  2. When rumination counts: Perceived social support and heart rate variability in daily life.

    PubMed

    Gerteis, Ann Kathrin S; Schwerdtfeger, Andreas R

    2016-07-01

    Rumination and social support could modulate cardiac activity. Although both variables are somehow interrelated, they are often studied independently, and their interplay is seldom considered. We aimed to analyze the interaction of rumination and perceived social support on vagally mediated heart rate variability (HRV) in daily life. The sample consisted of 117 healthy participants (57% female, mean age = 27.9, SD = 5.5 years). Ambulatory HRV (root mean squared successive differences), respiration, body position, and body movements were recorded continuously on three consecutive weekdays. Momentary social, situational, and cognitive-affective variables (affect, ruminative thoughts, perceived social support) were assessed using a computerized diary. There was a significant interaction between momentary rumination and perceived social support on ambulatory HRV: When participants were involved in social interactions with low social support, concurrent rumination was associated with attenuated HRV. However, when rumination was accompanied by a strong sense of support, HRV significantly increased. The quality of social interactions and rumination seem to interact in daily life to predict cardiac autonomic control. The results stress the necessity to consider the interplay of psychological and social factors in order to evaluate beneficial or adverse effects on cardiac health. PMID:27137911

  3. Leukocyte count and erythrocyte sedimentation rate as diagnostic factors in febrile convulsion.

    PubMed

    Rahbarimanesh, Ali Akbar; Salamati, Peyman; Ashrafi, Mohammadreza; Sadeghi, Manelie; Tavakoli, Javad

    2011-01-01

    Febrile convulsion (FC) is the most common seizure disorder in childhood. white blood cell (WBC) and erythrocyte sedimentation rate (ESR) are commonly measured in FC. Trauma, vomiting and bleeding can also lead to WBC and ESR so the blood tests must carefully be interpreted by the clinician. In this cross sectional study 410 children(163 with FC), aged 6 months to 5 years, admitted to Bahrami Children hospital in the first 48 hours of their febrile disease, either with or without seizure, were evaluated over an 18 months period. Age, sex, temperature; history of vomiting, bleeding or trauma; WBC, ESR and hemoglobin were recorded in all children. There was a significant increase of WBC (P<0.001) in children with FC so we can deduct that leukocytosis encountered in children with FC can be due to convulsion in itself. There was no significant difference regarding ESR (P=0.113) between the two groups. In fact, elevated ESR is a result of underlying pathology. In stable patients who don't have any indication of lumbar puncture, there's no need to assess WBC and ESR as an indicator of underlying infection. If the patient is transferred to pediatric ward and still there's no reason to suspect a bacterial infection, there is no need for WBC test. PMID:21960077

  4. Two-photon fluorescence correlation spectroscopy with high count rates and low background using dielectric microspheres

    PubMed Central

    Aouani, Heykel; Schön, Peter; Brasselet, Sophie; Rigneault, Hervé; Wenger, Jérôme

    2010-01-01

    Two-photon excitation fluorescence is a powerful technique commonly used for biological imaging. However, the low absorption cross section of this non-linear process is a critical issue for performing biomolecular spectroscopy at the single molecule level. Enhancing the two-photon fluorescence signal would greatly improve the effectiveness of this technique, yet current methods struggle with medium enhancement factors and/or high background noise. Here, we show that the two-photon fluorescence signal from single Alexa Fluor 488 molecules can be enhanced up to 10 times by using a 3 µm diameter latex sphere while adding almost no photoluminescence background. We report a full characterization of the two-photon fluorescence enhancement by a single microsphere using fluorescence correlation spectroscopy. This opens new routes to enhance non-linear optical signals and extend biophotonic applications. PMID:21258531

  5. A placebo-controlled study examining the effect of allopurinol on heart rate variability and dysrhythmia counts in chronic heart failure

    PubMed Central

    Shehab, Abdullah M A; Butler, Robert; MacFadyen, Robert J; Struthers, Allan D

    2001-01-01

    Aims Allopurinol improves endothelial function in chronic heart failure by reducing oxidative stress. We wished to explore if such an effect would attenuate autonomic dysfunction in CHF in line with many other effective therapies in CHF. Methods We performed a prospective, randomized, double-blind cross-over study in 16 patients with NYHA Class II-IV chronic heart failure (mean age 67 ± 10 years, 13 male, comparing allopurinol (2 months) at a daily dose of 300 mg (if creatinine < 150 µmol l−1) or 100 mg (if creatinine > 150 µmol l−1) with matched placebo. Mean heart rate and dysrhythmia counts were recorded from 24 h Holter tapes at monthly intervals for 6 months. We assessed autonomic function using standard time domain heart rate variability parameters (HRV): SDNN, SDANN, SDNN index, rMSSD and TI. Results Allopurinol had no significant effect on heart rate variability compared with placebo; the results are expressed as a difference in means ± s.d. with 95% confidence interval (CI) between allopurinol and placebo: SDNN mean=6.5 ± 4.8 ms, P = 0.18 and 95% CI (−3.7, 17); TI mean=−2.1 ± 1.4, P = 0.16 and 95% CI (−5.2, 0.8); SDANN mean=−2.8 ± 7 ms, P = 0.68 and 95% CI (−18, 12); SDNNi mean=2 ± 6.6, P = 0.7 and 95% CI (−12, 16); RMSSD mean=−0.9 ± 2, P = 0.68 and 95% CI (−5.6, 3.7). For mean heart rate the corresponding results were 0.9 ± 1.4, P = 0.5 and 95% CI (−2, 3.8). Log 24 h ventricular ectopic counts (VEC) were 0.032 ± 0.37, P = 0.7 and 95% CI (−0.1, 0.2). Patient compliance with study medication was good since allopurinol showed its expected effect of reducing plasma uric acid (P < 0.001). Conclusions Allopurinol at doses, which are known to reduce oxidative stress appear to have no significant effect on resting autonomic tone, as indicated by time domain heart rate variability or on dysrhythmia count in stable heart failure patients. PMID:11318768

  6. Single Photon Counting Performance and Noise Analysis of CMOS SPAD-Based Image Sensors.

    PubMed

    Dutton, Neale A W; Gyongy, Istvan; Parmesan, Luca; Henderson, Robert K

    2016-01-01

    SPAD-based solid state CMOS image sensors utilising analogue integrators have attained deep sub-electron read noise (DSERN) permitting single photon counting (SPC) imaging. A new method is proposed to determine the read noise in DSERN image sensors by evaluating the peak separation and width (PSW) of single photon peaks in a photon counting histogram (PCH). The technique is used to identify and analyse cumulative noise in analogue integrating SPC SPAD-based pixels. The DSERN of our SPAD image sensor is exploited to confirm recent multi-photon threshold quanta image sensor (QIS) theory. Finally, various single and multiple photon spatio-temporal oversampling techniques are reviewed. PMID:27447643

  7. Single Photon Counting Performance and Noise Analysis of CMOS SPAD-Based Image Sensors

    PubMed Central

    Dutton, Neale A. W.; Gyongy, Istvan; Parmesan, Luca; Henderson, Robert K.

    2016-01-01

    SPAD-based solid state CMOS image sensors utilising analogue integrators have attained deep sub-electron read noise (DSERN) permitting single photon counting (SPC) imaging. A new method is proposed to determine the read noise in DSERN image sensors by evaluating the peak separation and width (PSW) of single photon peaks in a photon counting histogram (PCH). The technique is used to identify and analyse cumulative noise in analogue integrating SPC SPAD-based pixels. The DSERN of our SPAD image sensor is exploited to confirm recent multi-photon threshold quanta image sensor (QIS) theory. Finally, various single and multiple photon spatio-temporal oversampling techniques are reviewed. PMID:27447643

  8. Count rate studies of a box-shaped PET breast imaging system comprised of position sensitive avalanche photodiodes utilizing monte carlo simulation.

    PubMed

    Foudray, Angela M K; Habte, Frezghi; Chinn, Garry; Zhang, Jin; Levin, Craig S

    2006-01-01

    We are investigating a high-sensitivity, high-resolution positron emission tomography (PET) system for clinical use in the detection, diagnosis and staging of breast cancer. Using conventional figures of merit, design parameters were evaluated for count rate performance, module dead time, and construction complexity. The detector system modeled comprises extremely thin position-sensitive avalanche photodiodes coupled to lutetium oxy-orthosilicate scintillation crystals. Previous investigations of detector geometries with Monte Carlo indicated that one of the largest impacts on sensitivity is local scintillation crystal density when considering systems having the same average scintillation crystal densities (same crystal packing fraction and system solid-angle coverage). Our results show the system has very good scatter and randoms rejection at clinical activity ranges ( approximately 200 muCi). PMID:17645997

  9. Children's Performance on the "Give X" Task: A Microgenetic Analysis of "Counting" and "Grabbing" Behaviour

    ERIC Educational Resources Information Center

    Chetland, Elizabeth; Fluck, Michael

    2007-01-01

    Children's understanding of the cardinal significance of counting is often assessed by the "give x" task, in which they are categorized as "counters" or "grabbers". Previous research indicates a sudden stage-like shift, implying insight into a principle. Employing a microgenetic approach, the present study was designed to explore whether this…

  10. Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency-Fusion Neutronics Source

    SciTech Connect

    Shinohara, K. Ochiai, K.; Sukegawa, A.; Ishii, K.; Kitajima, S.; Baba, M.; Sasao, M.

    2014-11-15

    In order to increase the count rate capability of a neutron detection system as a whole, we propose a multi-stage neutron detection system. Experiments to test the effectiveness of this concept were carried out on Fusion Neutronics Source. Comparing four configurations of alignment, it was found that the influence of an anterior stage on a posterior stage was negligible for the pulse height distribution. The two-stage system using 25 mm thickness scintillator was about 1.65 times the count rate capability of a single detector system for d-D neutrons and was about 1.8 times the count rate capability for d-T neutrons. The results suggested that the concept of a multi-stage detection system will work in practice.

  11. Multiple-factor influences upon feeding flight rates at wading bird colonies (Alias: Are flight-line counts useful?)

    USGS Publications Warehouse

    Erwin, R.M.; Ogden, J.C.

    1979-01-01

    The temporal patterns of feeding, resting, and reproductive behavior in colonial wading birds have been studied by a number of investigators, both on a short-term (daily) and long-term (annual) basis. In coastal marine environments, activities at colonies are influenced by tides, time of day and phase of the nesting cycle. The purpose of this paper is twofold: (1) to examine the effects of tide, time of day (physical factors), nesting phase, colony site, and species identity (biological factors) on feeding flight rates at breeding colonies and, as a result of this, (2) to evaluate the usefulness of feeding flight counts as an index of the number of nests in the colony. Earlier work suggests that the relationship between the number of individuals flying to and from the nesting colony may be quite consistent with nest numbers. Thus, by monitoring flights from remote locations, observers might obtain relatively accurate census data while minimizing time and disturbance at colonies. Recent concern for the deleterious impact of humans at waterbird colonies underscores the need to investigate alternative census methods.

  12. Performance of a Discrete Wavelet Transform for Compressing Plasma Count Data and its Application to the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission

    NASA Technical Reports Server (NTRS)

    Barrie, Alexander C.; Yeh, Penshu; Dorelli, John C.; Clark, George B.; Paterson, William R.; Adrian, Mark L.; Holland, Matthew P.; Lobell, James V.; Simpson, David G.; Pollock, Craig J.; Moore, Thomas E.

    2015-01-01

    Plasma measurements in space are becoming increasingly faster, higher resolution, and distributed over multiple instruments. As raw data generation rates can exceed available data transfer bandwidth, data compression is becoming a critical design component. Data compression has been a staple of imaging instruments for years, but only recently have plasma measurement designers become interested in high performance data compression. Missions will often use a simple lossless compression technique yielding compression ratios of approximately 2:1, however future missions may require compression ratios upwards of 10:1. This study aims to explore how a Discrete Wavelet Transform combined with a Bit Plane Encoder (DWT/BPE), implemented via a CCSDS standard, can be used effectively to compress count information common to plasma measurements to high compression ratios while maintaining little or no compression error. The compression ASIC used for the Fast Plasma Investigation (FPI) on board the Magnetospheric Multiscale mission (MMS) is used for this study. Plasma count data from multiple sources is examined: resampled data from previous missions, randomly generated data from distribution functions, and simulations of expected regimes. These are run through the compression routines with various parameters to yield the greatest possible compression ratio while maintaining little or no error, the latter indicates that fully lossless compression is obtained. Finally, recommendations are made for future missions as to what can be achieved when compressing plasma count data and how best to do so.

  13. Note: Simple calibration of the counting-rate dependence of the timing shift of single photon avalanche diodes by photon interval analysis

    SciTech Connect

    Otosu, Takuhiro; Ishii, Kunihiko; Tahara, Tahei

    2013-03-15

    The counting-rate dependence of the temporal response of single photon avalanche diodes (SPADs) is a critical issue for the accurate determination of the fluorescence lifetime. In this study, the response of SPADs was examined with analyzing the time interval of the detected photons. The results clearly show that the shift of the detection timing causes the counting-rate dependence of the temporal response, and this timing shift is solely determined by the time interval from the preceding photon. We demonstrate that this timing instability is readily calibrated by utilizing the macrotime data taken with the time-tag mode that is implemented in the time-correlated single photon counting modules.

  14. Scheduling and performance evaluation of high line-rate space-wavelength routed switch for datacenter

    NASA Astrophysics Data System (ADS)

    Huang, Qirui; Cheng, Xiaofei; Zhou, Luying

    In this paper, we investigate the performance of a high line-rate space-wavelength routed switch to assess its potential for use in large-scale datacenters. A scheduling technique is introduced for the switch to address challenges in packet arbitration taking into account a high line rate and large port-count. The traffic performance in terms of packet loss rate and latency of the switch is evaluated by simulations under various traffic patterns. The results show that even under burst traffic conditions, the packet loss rate and latency of the switch are almost independent of the switch size, which indicates that the switch could support a large number of nodes for switching without significant performance deterioration for both fixed and variable packet sizes. It is also found that a slight increase in the number of tunable transmitters in each node could lead to a great reduction in packet loss and latency for the switch.

  15. Performance of focal plane arrays for the photon counting arrays (PCAR) program

    NASA Astrophysics Data System (ADS)

    Blessinger, Michael A.; Enriquez, Marlon; Groppe, Joseph V.; Flynn, Kevin; Sudol, Thomas M.; Onat, Bora M.; Kleinhans, William E.

    2007-04-01

    The DARPA PCAR program is sponsoring the development of low noise, near infrared (1.5 μm wavelength) focal plane arrays (FPAs) for night vision applications. The first phase of this work has produced a collection of 640 x 512 pixel, 20 μm pitch FPAs with low noise. The approach was to design four different read out integrated circuits (ROICs), all compatible with the same bump-bonded InGaAs photodiode detector array. Two of the designs have capacitive transimpedance amplifier (CTIA) pixels, each with a somewhat different amplifier design and with two different sizes of small integration capacitors. The third design is a source follower per detector (SFD) pixel, integrating on the detector capacitance. The fourth design also integrates on the detector capacitance, but uses a moderate gain, in-pixel amplifier to boost the signal level, and also has a differential pixel output. All four designs require off-chip correlated sampling to achieve the desired noise level. The correlated sampling is performed digitally in the data acquisition software. Each design is capable of 30 frames per second read out rate, and has a dynamic range of 1000:1 using a rolling, non-snapshot integration. The designs were fabricated in a standard CMOS foundry process, and were bump-bonded to InGaAs detector arrays. All four designs are working without any significant design errors, and are producing low noise imaging, with less than 50 electrons rms noise per pixel after correlated double sampling.

  16. Neutron monitors and muon detectors for solar modulation studies: Interstellar flux, yield function, and assessment of critical parameters in count rate calculations

    NASA Astrophysics Data System (ADS)

    Maurin, D.; Cheminet, A.; Derome, L.; Ghelfi, A.; Hubert, G.

    2015-01-01

    Particles count rates at given Earth location and altitude result from the convolution of (i) the interstellar (IS) cosmic-ray fluxes outside the solar cavity, (ii) the time-dependent modulation of IS into Top-of-Atmosphere (TOA) fluxes, (iii) the rigidity cut-off (or geomagnetic transmission function) and grammage at the counter location, (iv) the atmosphere response to incoming TOA cosmic rays (shower development), and (v) the counter response to the various particles/energies in the shower. Count rates from neutron monitors or muon counters are therefore a proxy to solar activity. In this paper, we review all ingredients, discuss how their uncertainties impact count rate calculations, and how they translate into variation/uncertainties on the level of solar modulation ϕ (in the simple Force-Field approximation). The main uncertainty for neutron monitors is related to the yield function. However, many other effects have a significant impact, at the 5-10% level on ϕ values. We find no clear ranking of the dominant effects, as some depend on the station position and/or the weather and/or the season. An abacus to translate any variation of count rates (for neutron and μ detectors) to a variation of the solar modulation ϕ is provided.

  17. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22

    NASA Astrophysics Data System (ADS)

    Silva, H. G.; Lopes, I.

    2016-07-01

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  18. Performance of TSI 3760 condensation nuclei counter at reduced pressures and flow rates

    SciTech Connect

    Zhiqun Zhang; Liu, B.Y.H. )

    1991-01-01

    This article describes an experimental study of the performance of the TSI model 3760 clean room condensation nuclei counter (CNC) at various pressures and flow rates. Studies were made to determine the counting efficiency of the instrument in the pressure range of 0.1-1 atom and flow rate range of 0.15-1.4 L/min. The counting efficiency curves were found to be shifted to larger particle sizes as the pressure or flow rate was reduced. The low pressure and low flow rate limits of the instrument were also determined. The numerical model developed in a previous study was used to predict the performance of the CNC. The numerical results were compared with the experimental data and found to agree well in the pressure range of 0.2-1.0 atm and flow rate range of 0.3-1.4 L/min. Discrepancies were found to be more significant at the lower pressures and flow rates.

  19. On performance of parametric and distribution-free models for zero-inflated and over-dispersed count responses.

    PubMed

    Tang, Wan; Lu, Naiji; Chen, Tian; Wang, Wenjuan; Gunzler, Douglas David; Han, Yu; Tu, Xin M

    2015-10-30

    Zero-inflated Poisson (ZIP) and negative binomial (ZINB) models are widely used to model zero-inflated count responses. These models extend the Poisson and negative binomial (NB) to address excessive zeros in the count response. By adding a degenerate distribution centered at 0 and interpreting it as describing a non-risk group in the population, the ZIP (ZINB) models a two-component population mixture. As in applications of Poisson and NB, the key difference between ZIP and ZINB is the allowance for overdispersion by the ZINB in its NB component in modeling the count response for the at-risk group. Overdispersion arising in practice too often does not follow the NB, and applications of ZINB to such data yield invalid inference. If sources of overdispersion are known, other parametric models may be used to directly model the overdispersion. Such models too are subject to assumed distributions. Further, this approach may not be applicable if information about the sources of overdispersion is unavailable. In this paper, we propose a distribution-free alternative and compare its performance with these popular parametric models as well as a moment-based approach proposed by Yu et al. [Statistics in Medicine 2013; 32: 2390-2405]. Like the generalized estimating equations, the proposed approach requires no elaborate distribution assumptions. Compared with the approach of Yu et al., it is more robust to overdispersed zero-inflated responses. We illustrate our approach with both simulated and real study data. PMID:26078035

  20. Performance Funding of Public Higher Education: Results Should Count. Rockefeller Reports.

    ERIC Educational Resources Information Center

    Burke, Joseph C.; Serban, Andreea M.

    This report examines performance funding and performance budgeting in public higher education, based on studies conducted by the Nelson A. Rockefeller Institute of Government (New York). A recent survey indicated that 10 states currently have performance funding for public colleges and universities, that 8 states currently use performance…

  1. Diagnostic Accuracy of the Quantitative C-Reactive Protein, Erythrocyte Sedimentation Rate and White Blood Cell Count in Urinary Tract Infections among Infants and Children

    PubMed Central

    AYAZI, Parviz; MAHYAR, Abolfazl; DANESHI, Mohammad Mahdi; JAHANI HASHEMI, Hassan; PIROUZI, Mahdieh; ESMAILZADEHHA, Neda

    2013-01-01

    Objectives: The aim of this study was to evaluate the diagnostic accuracy of the quantitative C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and white blood cell (WBC) count in urinary tract infections (UTI) among hospitalised infants and children in Qazvin, Iran. Methods: This cross-sectional study was conducted on 127 hospitalised children ranging in age from 2 months to 12 years old 31.79 months (SD 30.73) who were suspected of having a UTI and who did not receive antibiotics prior to being seen at a Qazvin teaching children’s hospital between 2005 and 2006. A urine analysis (U/A) and urine culture (U/C) were performed. The blood was taken for CRP, ESR and WBC analyses. U/C has been considered the gold standard test for a UTI and dimercaptosuccinic acid renal scintigraphy (DMSA) as the gold standard for an upper UTI (pyelonephritis). These tests were used to determine the diagnostic accuracy, which is represented as the percent of correct results. Results: Within the study population, 72 patients (56.7%) were younger than two years old 9.86 months (SD 4.56) and 55 (43.3%) were older than two years old 63.58 months (SD 30.96). One hundred and two patients (80.3%) were female. There were 100 cases that had a positive U/C. Of the patients with a positive U/C, 81 had pyuria (WBC more than 5/hpf), 71 had a peripheral WBC count of more than 10 000 /mL, 95 had a CRP of more than 10 mg/L and 82 had an ESR > 10 mm/h. The sensitivity and specificity as well as the positive and negative predictive values and the accuracy of CRP when using U/C as the gold standard were, respectively, 96%, 11.1%, 80.2%, 50%, and 78%; when using ESR as the gold standard were, respectively, 55%, 40%, 77.6%, 17.2%, and 52%; and when using WBC counts as the gold standard were, respectively, 69%, 52%, 86.6%, 35.6%, and 65%. The accuracy of CRP, ESR and WBC counts when considering the DMSA as the gold standard were 58.3%, 62.8%, and 64.5%, respectively. Conclusion: Although acute

  2. Photon counting modules using RCA silicon avalanche photodiodes

    NASA Technical Reports Server (NTRS)

    Lightstone, Alexander W.; Macgregor, Andrew D.; Macsween, Darlene E.; Mcintyre, Robert J.; Trottier, Claude; Webb, Paul P.

    1989-01-01

    Avalanche photodiodes (APD) are excellent small area, solid state detectors for photon counting. Performance possibilities include: photon detection efficiency in excess of 50 percent; wavelength response from 400 to 1000 nm; count rate to 10 (exp 7) counts per sec; afterpulsing at negligible levels; timing resolution better than 1 ns. Unfortunately, these performance levels are not simultaneously available in a single detector amplifier configuration. By considering theoretical performance predictions and previous and new measurements of APD performance, the anticipated performance of a range of proposed APD-based photon counting modules is derived.

  3. Rater Effects in Clinical Performance Ratings of Surgery Residents

    ERIC Educational Resources Information Center

    Iramaneerat, Cherdsak; Myford, Carol M.

    2006-01-01

    A multi-faceted Rasch measurement (MFRM) approach was used to analyze clinical performance ratings of 24 first-year residents in one surgery residency program in Thailand to investigate three types of rater effects: leniency, rater inconsistency, and restriction of range. Faculty from 14 surgical services rated the clinical performance of…

  4. Evaluation of conventional imaging performance in a research whole-body CT system with a photon-counting detector array

    NASA Astrophysics Data System (ADS)

    Yu, Zhicong; Leng, Shuai; Jorgensen, Steven M.; Li, Zhoubo; Gutjahr, Ralf; Chen, Baiyu; Halaweish, Ahmed F.; Kappler, Steffen; Yu, Lifeng; Ritman, Erik L.; McCollough, Cynthia H.

    2016-02-01

    This study evaluated the conventional imaging performance of a research whole-body photon-counting CT system and investigated its feasibility for imaging using clinically realistic levels of x-ray photon flux. This research system was built on the platform of a 2nd generation dual-source CT system: one source coupled to an energy integrating detector (EID) and the other coupled to a photon-counting detector (PCD). Phantom studies were conducted to measure CT number accuracy and uniformity for water, CT number energy dependency for high-Z materials, spatial resolution, noise, and contrast-to-noise ratio. The results from the EID and PCD subsystems were compared. The impact of high photon flux, such as pulse pile-up, was assessed by studying the noise-to-tube-current relationship using a neonate water phantom and high x-ray photon flux. Finally, clinical feasibility of the PCD subsystem was investigated using anthropomorphic phantoms, a cadaveric head, and a whole-body cadaver, which were scanned at dose levels equivalent to or higher than those used clinically. Phantom measurements demonstrated that the PCD subsystem provided comparable image quality to the EID subsystem, except that the PCD subsystem provided slightly better longitudinal spatial resolution and about 25% improvement in contrast-to-noise ratio for iodine. The impact of high photon flux was found to be negligible for the PCD subsystem: only subtle high-flux effects were noticed for tube currents higher than 300 mA in images of the neonate water phantom. Results of the anthropomorphic phantom and cadaver scans demonstrated comparable image quality between the EID and PCD subsystems. There were no noticeable ring, streaking, or cupping/capping artifacts in the PCD images. In addition, the PCD subsystem provided spectral information. Our experiments demonstrated that the research whole-body photon-counting CT system is capable of providing clinical image quality at clinically realistic levels of x

  5. Evaluation of conventional imaging performance in a research whole-body CT system with a photon-counting detector array

    PubMed Central

    Yu, Zhicong; Leng, Shuai; Jorgensen, Steven M; Li, Zhoubo; Gutjahr, Ralf; Chen, Baiyu; Halaweish, Ahmed F; Kappler, Steffen; Yu, Lifeng; Ritman, Erik L; McCollough, Cynthia H

    2016-01-01

    This study evaluated the conventional imaging performance of a research whole-body photon-counting CT system and investigated its feasibility for imaging using clinically realistic levels of x-ray photon flux. This research system was built on the platform of a 2nd generation dual-source CT system: one source coupled to an energy integrating detector (EID) and the other coupled to a photon-counting detector (PCD). Phantom studies were conducted to measure CT number accuracy and uniformity for water, CT number energy dependency for high-Z materials, spatial resolution, noise, and contrast-to-noise ratio. The results from the EID and PCD subsystems were compared. The impact of high photon flux, such as pulse pile-up, was assessed by studying the noise-to-tube-current relationship using a neonate water phantom and high x-ray photon flux. Finally, clinical feasibility of the PCD subsystem was investigated using anthropomorphic phantoms, a cadaveric head, and a whole-body cadaver, which were scanned at dose levels equivalent to or higher than those used clinically. Phantom measurements demonstrated that the PCD subsystem provided comparable image quality to the EID subsystem, except that the PCD subsystem provided slightly better longitudinal spatial resolution and about 25% improvement in contrast-to-noise ratio for iodine. The impact of high photon flux was found to be negligible for the PCD subsystem: only subtle high-flux effects were noticed for tube currents higher than 300 mA in images of the neonate water phantom. Results of the anthropomorphic phantom and cadaver scans demonstrated comparable image quality between the EID and PCD subsystems. There were no noticeable ring, streaking, or cupping/capping artifacts in the PCD images. In addition, the PCD subsystem provided spectral information. Our experiments demonstrated that the research whole-body photon-counting CT system is capable of providing clinical image quality at clinically realistic levels of x

  6. A parametric study of rate of advance and area coverage rate performance of synthetic aperture radar.

    SciTech Connect

    Raynal, Ann Marie; Hensley, William Heydon,; Burns, Bryan L.; Doerry, Armin Walter

    2014-11-01

    The linear ground distance per unit time and ground area covered per unit time of producing synthetic aperture radar (SAR) imagery, termed rate of advance (ROA) and area coverage rate (ACR), are important metrics for platform and radar performance in surveillance applications. These metrics depend on many parameters of a SAR system such as wavelength, aircraft velocity, resolution, antenna beamwidth, imaging mode, and geometry. Often the effects of these parameters on rate of advance and area coverage rate are non-linear. This report addresses the impact of different parameter spaces as they relate to rate of advance and area coverage rate performance.

  7. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

    PubMed Central

    Zhu, Yazhong; Luo, Yimeng; Ma, Hongye; Wang, Yan

    2016-01-01

    A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m3. The maximum elimination capacity of 36.0 g/(m3 h) occurred at an inlet loading rate of 45.9 g/(m3 h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs. PMID:27231662

  8. Competencies That Count: Strategies for Assessing High-Performance Skills. LAB Working Paper No. 2.

    ERIC Educational Resources Information Center

    Allen, Lili

    This guide provides a "road map" to the various ways that schools and employers assess high-performance competencies, such as problem solving, information management, and communication and negotiation skills. The guide begins with a brief analysis of why it is important to assess these skills in light of the current standards environment in…

  9. The New X-ray Mapping: X-ray Spectrum Imaging above 100 kHz Output Count Rate with the Silicon Drift Detector

    NASA Astrophysics Data System (ADS)

    Newbury, Dale E.

    2006-02-01

    Electron-excited X-ray mapping is a key operational mode of the scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometry (EDS). The popularity of X-ray mapping persists despite the significant time penalty due to the relatively low output count rates, typically less than 25 kHz, that can be processed with the conventional EDS. The silicon drift detector (SDD) uses the same measurement physics, but modifications to the detector structure permit operation at a factor of 5 10 times higher than conventional EDS for the same resolution. Output count rates as high as 500 kHz can be achieved with 217 eV energy resolution (at MnK[alpha]). Such extraordinarily high count rates make possible X-ray mapping through the method of X-ray spectrum imaging, in which a complete spectrum is captured at each pixel of the scan. Useful compositional data can be captured in less than 200 s with a pixel density of 160 × 120. Applications to alloy and rock microstructures, ultrapure materials with rare inclusions, and aggregate particles with complex chemistry illustrate new approaches to characterization made practical by high-speed X-ray mapping with the SDD. a b

  10. Low-energy (<1.6MeV) particle counting rates and solar magnetic activity: A study of the 1980 anomaly

    NASA Astrophysics Data System (ADS)

    Rodríguez-Pacheco, J.; Sequeiros, J.; del Peral, L.; Medina, J.; Wenzel, K.-P.

    1997-05-01

    We present a study of the relation between the solar magnetic activity (centered in sunspots, flares types N and B, and long-duration X class flares) and the counting rates of particles in interplanetary space with energies below 1.6 MeV obtained from the Low-Energy Proton Experiment (DFH-EPAS) onboard International Sun-Earth Explorer spacecraft, during the period 1978-1982. Our study shows that the particle counting rates are neither correlated with sunspots number nor with flares type N, but they are correlated with flares type B and mainly with long-duration X class flares. The origin of the low counting rates of particles detected during the years 1979-1980 is investigated as well. The disappearance of the strongest interplanetary shocks during that period can explain this phenomenon, at least within the energy range studied. The absence of any anomalous behavior in the flares type B and in the long-duration X class flares during this period suggests that this shock behavior can be produced by anomalous conditions of the interplanetary magnetic field during the Sun's polar magnetic field reversal.

  11. Background Count Rates and the Anti-Coincidence Detector on the Instrument on Astro-E2

    NASA Technical Reports Server (NTRS)

    Kilbourne, C. A.

    2004-01-01

    Minimum ionizing particles incident on the XRS microcalorimeter array will deposit energy in the pixels on the same scale as an x-ray photon and would be confused with x-rays without an anti-coincidence detector. The XRS anti-coincidence detector is a silicon ionization detector placed directly behind the calorimeter array. Given an isotropic particle flux, 98% of those particles that pass through a calorimeter pixel will also deposit energy in the anti-coincidence detector. Particle events that are not rejected by coincidence are those that pass through at small angles relative to the plane of the array, and thus deposit more energy. Modeling with GEANT4 showed that only 0.1% of all protons incident on the array miss the anti-coincidence detector yet deposit less than 10 keV in a pixel. The unrejected background will thus be dominated by secondary events; we will provide an estimate of this rate. Protons incident on the thick silicon frame around the active area of the array deposit enough energy t o heat the whole chip slightly. This results in small simultaneous pulses on multiple pixels. These can be easily rejected by pixel-to-pixel coincidence. We will discuss the impact of these events on the instrument dead time and will present the expected rate. We will present laboratory background data demonstrating the performance of the anti-coincidence detector and the effectiveness of coincidence analysis in the laboratory environment.

  12. Inflight performance of a second-generation photon-counting 3D imaging lidar

    NASA Astrophysics Data System (ADS)

    Degnan, John; Machan, Roman; Leventhal, Ed; Lawrence, David; Jodor, Gabriel; Field, Christopher

    2008-04-01

    Sigma Space Corporation has recently developed a compact 3D imaging and polarimetric lidar suitable for use in a small aircraft or mini-UAV. A frequency-doubled Nd:YAG microchip laser generates 6 microjoule, subnanosecond pulses at fire rates up to 22 kHz. A Diffractive Optical Element (DOE) breaks the 532 nm beam into a 10x10 array of Gaussian beamlets, each containing about 1 mW of laser power (50 nJ @ 20 kHz). The reflected radiation in each beamlet is imaged by the receive optics onto individual pixels of a high efficiency, 10x10 pixel, multistop detector. Each pixel is then input to one channel of a 100 channel, multistop timer demonstrated to have a 93 picosecond timing (1.4 cm range) resolution and an event recovery time of only 1.6 nsec. Thus, each green laser pulse produces a 100 pixel volumetric 3D image. The residual infrared energy at 1064 nm is used for polarimetry. The scan pattern and frequency of a dual wedge optical scanner, synchronized to the laser fire rate, are tailored to provide contiguous coverage of a ground scene in a single overflight. In both rooftop and preliminary flight tests, the lidar has produced high spatial resolution 3D images of terrain, buildings, tree structures, power lines, and bridges with a data acquisition rate up to 2.2 million multistop 3D pixels per second. Current tests are aimed at defining the lidar's ability to image through water columns and tree canopies.

  13. An investigation of factors influencing accountability and performance ratings.

    PubMed

    Roch, Sylvia G; McNall, Laurel A

    2007-09-01

    The authors explored whether accountability has implications for performance ratings and investigated factors that may influence both accountability and performance ratings. Specifically, they investigated (a) whether feelings of accountability are directly related to performance ratings, (b) whether experimental manipulations that have been proposed to manipulate accountability in fact do so, and (c) the role of motivation-related constructs. They developed and tested a model of factors proposed to influence accountability and performance ratings. Results from 334 raters in an upward feedback situation in a classroom context provide empirical support that feelings of accountability influence rating level, as do perceptions of anonymity and the importance raters place on their jobs. However, neither anonymity nor importance perceptions were related to feelings of accountability. PMID:17933404

  14. The impact of pitch counts and days of rest on performance among major-league baseball pitchers.

    PubMed

    Bradbury, John C; Forman, Sean L

    2012-05-01

    Although the belief that overuse can harm pitchers is widespread, there exists little evidence to show that the number of pitches thrown and the days of rest affect future performance and injury among adults. The purpose of this study is to quantify the effects of pitches thrown and the days of rest on pitcher performance. We examined performances of major-league baseball starting pitchers from 1988 to 2009 using fractional polynomial multiple regression to estimate the immediate and cumulative impact of pitches thrown and the days of rest on performance, while controlling for other factors that likely affect pitcher effectiveness. Estimates indicate each pitch thrown in the preceding game increased earned run average (ERA) by 0.007 in the following game. Each pitch averaged in the preceding 5 and 10 games increased the ERA by 0.014 and 0.022, respectively. Older pitchers were more sensitive to cumulative pitching loads than younger pitchers were, but they were less affected by pitches thrown in the preceding game. Rest days were weakly associated with performance. In summary, we found that there is a negative relationship between past pitches thrown and future performance that is virtually linear. The impact of the cumulative pitching load is larger than the impact of a single game. Rest days do not appear to have a large impact on performance. This study supports the popular notion that high pitching loads can dampen future performance; however, because the effect is small, pitch-count benchmarks have limited use for maintaining performance and possibly preventing injury. PMID:22344048

  15. A multivariate rate equation for variable-interval performance

    PubMed Central

    McDowell, J. J; Kessei, Robert

    1979-01-01

    A value-like parameter is introduced into a rate equation for describing variable-interval performance. The equation, derived solely from formal considerations, expresses rate of responding as a joint function of rate of reinforcement and “reinforcer power.” Preliminary tests of the rate equation show that it handles univariate data as well as Herrnstein's hyperbola. In addition, a form of Herrnstein's hyperbola can be derived from the equation, and it predicts forms of matching in concurrent situations. For the multivariate case, reinforcer values scaled in concurrent situations where matching is assumed to hold are taken as determinations of reinforcer power. The multivariate rate equation is fitted to an appropriate set of data and found to provide a good description of variable-interval performance when both rate and power of reinforcement are varied. Rate and power measures completely describe reinforcement. The effects of their joint variation are not predicted and cannot be described by Herrnstein's equation. PMID:16812130

  16. Laser transmitter design and performance for the slope imaging multi-polarization photon-counting lidar (SIMPL) instrument

    NASA Astrophysics Data System (ADS)

    Yu, Anthony W.; Harding, David J.; Dabney, Philip W.

    2016-03-01

    The Slope Imaging Multi-polarization Photon-counting Lidar (SIMPL) is a polarimetric, two-color, multi-beam push broom laser altimeter developed through the NASA Earth Science Technology Office Instrument Incubator Program. It has flown successfully on multiple airborne platforms beginning in 2008.1 It was developed to demonstrate new altimetry capabilities that combine height measurements and information about surface composition and properties. In this talk we will discuss the laser transmitter design and performance and present recent science data collected over the Greenland ice sheet and arctic sea ice in support of the second NASA Ice Cloud and land Elevation Satellite (ICESat-2) mission to be launched in 2017.2

  17. Predicting Supervisor, Peer, and Self Ratings of Intern Performance

    ERIC Educational Resources Information Center

    Kegel-Flom, Penelope

    1975-01-01

    Relationships between the ratings of interns by their supervisors, their peers, and the interns themselves on four dimensions are compared and analyzed in relationship to earlier measures of aptitude, achievement, and personality. Findings reported show supervisor ratings to be highest and admission variables to be unrelated to intern performance.…

  18. Effects of the presentation of false heart-rate feedback on the performance of two common heartbeat-detection tasks.

    PubMed

    Phillips, G C; Jones, G E; Rieger, E J; Snell, J B

    1999-07-01

    Research has indicated that performance on heartbeat counting tasks may be influenced by beliefs about heart rate. Sixty male subjects were administered the Schandry heartbeat counting task after viewing fast, slow, or no heart rate feedback. Subjects were also administered the Whitehead signal-detection type task. Results indicated that subjects who received fast or no heartbeat feedback performed better on the Schandry task than subjects who received slow feedback. Feedback presentation did not affect performance on the Whitehead task. These results suggest that the Schandry task is influenced by external variables (expectations, beliefs) beyond pure awareness of "discrete" visceral sensations and, thus, may not be as powerful a method for determining awareness of individual heartbeats as some other paradigms. PMID:10432800

  19. Theory research on performance of high-speed random bitstream ranging system based on single-photon counting

    NASA Astrophysics Data System (ADS)

    Shen, Shanshan; Chen, Qian; He, Weiji; Dai, Huidong

    2014-11-01

    This paper investigates the random bitstream ranging model and proposes a new output SNR model based on statistical optics theory. We study the relationship of SNR and the fraction of 1 in bitstream with different dead time by Monte Carlo simulation. Theory model is almost consistent with Monte Carlo simulation. The results show that with the fraction of randomly distributed 1-bits in transmitted pattern increased, the system SNR gets better first and then gets worse. Best pattern of transmitted bit stream according to different dead time leads to the best SNR. According to new output SNR model, low dead time brings better SNR. The system SNR increases firstly then gets down with the growing signal photon counts. At last, Gaussian distribution timing jitter of 440ps FWHM is introduced to reconstruct received bitstream pattern formed from the arrival times of returning single photon. We find that higher rate of bitstream brings higher possibility error of single time value. Suitable bits rate is restricted to 1 GHz according to jitter of 440ps FWHM to reduce the probability of ranging error.

  20. Fighter pilots' heart rate, heart rate variation and performance during an instrument flight rules proficiency test.

    PubMed

    Mansikka, Heikki; Virtanen, Kai; Harris, Don; Simola, Petteri

    2016-09-01

    Increased task demand will increase the pilot mental workload (PMWL). When PMWL is increased, mental overload may occur resulting in degraded performance. During pilots' instrument flight rules (IFR) proficiency test, PMWL is typically not measured. Therefore, little is known about workload during the proficiency test and pilots' potential to cope with higher task demands than those experienced during the test. In this study, fighter pilots' performance and PMWL was measured during a real IFR proficiency test in an F/A-18 simulator. PMWL was measured using heart rate (HR) and heart rate variation (HRV). Performance was rated using Finnish Air Force's official rating scales. Results indicated that HR and HRV differentiate varying task demands in situations where variations in performance are insignificant. It was concluded that during a proficiency test, PMWL should be measured together with the task performance measurement. PMID:27109324

  1. Total internal reflection fluorescence correlation spectroscopy (TIR-FCS) with low background and high count-rate per molecule

    NASA Astrophysics Data System (ADS)

    Hassler, Kai; Leutenegger, Marcel; Rigler, Per; Rao, Ramachandra; Rigler, Rudolf; Gösch, Michael; Lasser, Theo

    2005-09-01

    We designed a fluorescence correlation spectroscopy (FCS) system for measurements on surfaces. The system consists of an objective-type total internal reflection fluorescence (TIRF) microscopy setup, adapted to measure FCS. Here, the fluorescence exciting evanescent wave is generated by epi-illumination through the periphery of a high NA oil-immersion objective. The main advantages with respect to conventional FCS systems are an improvement in terms of counts per molecule (cpm) and a high signal to background ratio. This is demonstrated by investigating diffusion as well as binding and release of single molecules on a glass surface. Furthermore, the size and shape of the molecule detection efficiency (MDE) function was calculated, using a wave-vectorial approach and taking into account the influence of the dielectric interface on the emission properties of fluorophores.

  2. Improving Performance Appraisals: Confronting Subjective Factors That Influence Ratings.

    ERIC Educational Resources Information Center

    Kruger, Michael J.

    1986-01-01

    Explores implications of subjective factors that influence rating processes upon which formal performance appraisal systems are based and presents a strategy for addressing this problem which utilizes the critical incident method to focus objectively on employee behavior. A performance feedback worksheet to be utilized with this appraisal method…

  3. Impact of Performance-Funding on Retention and Graduation Rates

    ERIC Educational Resources Information Center

    Sanford, Thomas; Hunter, James M.

    2011-01-01

    As the architect of the oldest and most stable performance-funding program, Tennessee provides a unique opportunity to analyze the impact of changes in performance-funding policies on changes in institutional retention and six-year graduation rates over time. Utilizing spline linear mixed models, this study examines the impact of changes in…

  4. Ratings of Job Performance of Georgia Correctional Officers.

    ERIC Educational Resources Information Center

    Nosin, Jerome Alan

    Expansion and modification of a 27-item Delphi derived form for assessing campus police performance resulted in a 43-item form to measure job performance of correctional officers in the Georgia Department of Corrections. The self-rating scale, with a reliability coefficient of .995 (n=120) was subjected to factor analysis and varimax rotation and…

  5. Performance characterization of the Hubble Space Telescope Rate Gyro Assembly

    NASA Technical Reports Server (NTRS)

    Dougherty, H.; Rodden, J.; Reschke, L. F.; Tompetrini, K.; Weinstein, S. P.

    1986-01-01

    An account is given of the design features and performance characteristics of the Rate Gyro Assembly employed by the Hubble Space Telescope's Pointing Control System to effect accurate spacecraft maneuvers and support fine pointing telescope operation, in conjunction with the fine guidance sensors. The rate sensor attitude quantization is 0.00025 arcsec. Fine-pointing stability is the driver for gyro noise performance, while spacecraft-pointing accuracy requirements at the end of maneuvers has driven the gyro scale factor and mechanical alignment stability performance.

  6. 1-year retention rates and performance ratings: comparing associate degree, baccalaureate, and accelerated baccalaureate degree nurses.

    PubMed

    Weathers, Suzanne M; Raleigh, Edith D Hunt

    2013-09-01

    The purpose of this study was to examine 1-year retention and managerial performance ratings of newly licensed RNs (NLRNs) according to nursing education program types (associate degree, traditional baccalaureate, and accelerated 2nd degree baccalaureate). Findings revealed retention and performance differences, suggesting the possibility of tradeoffs related to educational program type when selecting NLRNs for open positions. PMID:23958525

  7. Multiplicity Counting

    SciTech Connect

    Geist, William H.

    2015-12-01

    This set of slides begins by giving background and a review of neutron counting; three attributes of a verification item are discussed: 240Pueff mass; α, the ratio of (α,n) neutrons to spontaneous fission neutrons; and leakage multiplication. It then takes up neutron detector systems – theory & concepts (coincidence counting, moderation, die-away time); detector systems – some important details (deadtime, corrections); introduction to multiplicity counting; multiplicity electronics and example distributions; singles, doubles, and triples from measured multiplicity distributions; and the point model: multiplicity mathematics.

  8. 5 CFR 9901.412 - Rating and rewarding performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Rating and rewarding performance. 9901.412 Section 9901.412 Administrative Personnel DEPARTMENT OF DEFENSE HUMAN RESOURCES MANAGEMENT AND LABOR RELATIONS SYSTEMS (DEPARTMENT OF DEFENSE-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF...

  9. School Performance Indicators, Accountability Ratings, and Student Achievement

    ERIC Educational Resources Information Center

    Jackson, Shirley A.; Lunenburg, Fred C.

    2010-01-01

    Researchers have been challenged to find school-level characteristics that make a difference in student achievement. This study focused on a diverse sample of 24 middle schools to examine differences between schools rated Exemplary, Recognized, Academically Acceptable, and Academically Unacceptable on four performance indicator dimensions:…

  10. Effective Rating Scale Development for Speaking Tests: Performance Decision Trees

    ERIC Educational Resources Information Center

    Fulcher, Glenn; Davidson, Fred; Kemp, Jenny

    2011-01-01

    Rating scale design and development for testing speaking is generally conducted using one of two approaches: the measurement-driven approach or the performance data-driven approach. The measurement-driven approach prioritizes the ordering of descriptors onto a single scale. Meaning is derived from the scaling methodology and the agreement of…

  11. Performance of high flow rate samplers for respirable particle collection.

    PubMed

    Lee, Taekhee; Kim, Seung Won; Chisholm, William P; Slaven, James; Harper, Martin

    2010-08-01

    The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m(-3) in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins-Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size ((50)d(ae)) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 microm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2-11 times based on gravimetric analysis. Dust loading inside the

  12. Performance of High Flow Rate Samplers for Respirable Particle Collection

    PubMed Central

    Lee, Taekhee; Kim, Seung Won; Chisholm, William P.; Slaven, James; Harper, Martin

    2010-01-01

    The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m−3 in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins–Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size (50dae) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 μm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2–11 times based on gravimetric analysis. Dust loading inside the high

  13. A yearly spraying of olive mill wastewater on agricultural soil over six successive years: impact of different application rates on olive production, phenolic compounds, phytotoxicity and microbial counts.

    PubMed

    Magdich, Salwa; Jarboui, Raja; Rouina, Béchir Ben; Boukhris, Makki; Ammar, Emna

    2012-07-15

    Olive mill wastewater (OMW) spraying effects onto olive-tree fields were investigated. Three OMW levels (50, 100 and 200 m(3)ha(-1)year(-1)) were applied over six successive years. Olive-crop yields, phenolic compounds progress, phytotoxicity and microbial counts were studied at different soil depths. Olive yield showed improvements with OMW level applied. Soil polyphenolic content increased progressively in relation to OMW levels in all the investigated layers. However, no significant difference was noted in lowest treatment rate compared to the control field. In the soil upper-layers (0-40 cm), five phenolic compounds were identified over six consecutive years of OMW-spraying. In all the soil-layers, the radish germination index exceeded 85%. However, tomato germination test values decreased with the applied OMW amount. For all treatments, microbial counts increased with OMW quantities and spraying frequency. Matrix correlation showed a strong relationship between soil polyphenol content and microorganisms, and a negative one to tomato germination index. PMID:22647243

  14. Counting missing values in a metabolite-intensity data set for measuring the analytical performance of a metabolomics platform.

    PubMed

    Huan, Tao; Li, Liang

    2015-01-20

    Metabolomics requires quantitative comparison of individual metabolites present in an entire sample set. Unfortunately, missing intensity values in one or more samples are very common. Because missing values can have a profound influence on metabolomic results, the extent of missing values found in a metabolomic data set should be treated as an important parameter for measuring the analytical performance of a technique. In this work, we report a study on the scope of missing values and a robust method of filling the missing values in a chemical isotope labeling (CIL) LC-MS metabolomics platform. Unlike conventional LC-MS, CIL LC-MS quantifies the concentration differences of individual metabolites in two comparative samples based on the mass spectral peak intensity ratio of a peak pair from a mixture of differentially labeled samples. We show that this peak-pair feature can be explored as a unique means of extracting metabolite intensity information from raw mass spectra. In our approach, a peak-pair peaking algorithm, IsoMS, is initially used to process the LC-MS data set to generate a CSV file or table that contains metabolite ID and peak ratio information (i.e., metabolite-intensity table). A zero-fill program, freely available from MyCompoundID.org , is developed to automatically find a missing value in the CSV file and go back to the raw LC-MS data to find the peak pair and, then, calculate the intensity ratio and enter the ratio value into the table. Most of the missing values are found to be low abundance peak pairs. We demonstrate the performance of this method in analyzing an experimental and technical replicate data set of human urine metabolome. Furthermore, we propose a standardized approach of counting missing values in a replicate data set as a way of gauging the extent of missing values in a metabolomics platform. Finally, we illustrate that applying the zero-fill program, in conjunction with dansylation CIL LC-MS, can lead to a marked improvement in

  15. Investigating the limits of PET/CT imaging at very low true count rates and high random fractions in ion-beam therapy monitoring

    SciTech Connect

    Kurz, Christopher Bauer, Julia; Conti, Maurizio; Guérin, Laura; Eriksson, Lars; Parodi, Katia

    2015-07-15

    Purpose: External beam radiotherapy with protons and heavier ions enables a tighter conformation of the applied dose to arbitrarily shaped tumor volumes with respect to photons, but is more sensitive to uncertainties in the radiotherapeutic treatment chain. Consequently, an independent verification of the applied treatment is highly desirable. For this purpose, the irradiation-induced β{sup +}-emitter distribution within the patient is detected shortly after irradiation by a commercial full-ring positron emission tomography/x-ray computed tomography (PET/CT) scanner installed next to the treatment rooms at the Heidelberg Ion-Beam Therapy Center (HIT). A major challenge to this approach is posed by the small number of detected coincidences. This contribution aims at characterizing the performance of the used PET/CT device and identifying the best-performing reconstruction algorithm under the particular statistical conditions of PET-based treatment monitoring. Moreover, this study addresses the impact of radiation background from the intrinsically radioactive lutetium-oxyorthosilicate (LSO)-based detectors at low counts. Methods: The authors have acquired 30 subsequent PET scans of a cylindrical phantom emulating a patientlike activity pattern and spanning the entire patient counting regime in terms of true coincidences and random fractions (RFs). Accuracy and precision of activity quantification, image noise, and geometrical fidelity of the scanner have been investigated for various reconstruction algorithms and settings in order to identify a practical, well-suited reconstruction scheme for PET-based treatment verification. Truncated listmode data have been utilized for separating the effects of small true count numbers and high RFs on the reconstructed images. A corresponding simulation study enabled extending the results to an even wider range of counting statistics and to additionally investigate the impact of scatter coincidences. Eventually, the recommended

  16. Determination of total Pu content in a Spent Fuel Assembly by Measuring Passive Neutron Count rate and Multiplication with the Differential Die-Away Instrument

    SciTech Connect

    Henzl, Vladimir; Croft, Stephen; Swinhoe, Martyn T.; Tobin, Stephen J.

    2012-07-18

    A key objective of the Next Generation Safeguards Initiative (NGSI) is to evaluate and develop non-destructive assay (NDA) techniques to determine the elemental plutonium content in a commercial-grade nuclear spent fuel assembly (SFA) [1]. Within this framework, we investigate by simulation a novel analytical approach based on combined information from passive measurement of the total neutron count rate of a SFA and its multiplication determined by the active interrogation using an instrument based on a Differential Die-Away technique (DDA). We use detailed MCNPX simulations across an extensive set of SFA characteristics to establish the approach and demonstrate its robustness. It is predicted that Pu content can be determined by the proposed method to a few %.

  17. Cultural values and performance appraisal: assessing the effects of rater self-construal on performance ratings.

    PubMed

    Mishra, Vipanchi; Roch, Sylvia G

    2013-01-01

    Much of the prior research investigating the influence of cultural values on performance ratings has focused either on conducting cross-national comparisons among raters or using cultural level individualism/collectivism scales to measure the effects of cultural values on performance ratings. Recent research has shown that there is considerable within country variation in cultural values, i.e. people in one country can be more individualistic or collectivistic in nature. Taking the latter perspective, the present study used Markus and Kitayama's (1991) conceptualization of independent and interdependent self-construals as measures of individual variations in cultural values to investigate within culture variations in performance ratings. Results suggest that rater self-construal has a significant influence on overall performance evaluations; specifically, raters with a highly interdependent self-construal tend to show a preference for interdependent ratees, whereas raters high on independent self-construal do not show a preference for specific type of ratees when making overall performance evaluations. Although rater self-construal significantly influenced overall performance evaluations, no such effects were observed for specific dimension ratings. Implications of these results for performance appraisal research and practice are discussed. PMID:23885636

  18. Counting Penguins.

    ERIC Educational Resources Information Center

    Perry, Mike; Kader, Gary

    1998-01-01

    Presents an activity on the simplification of penguin counting by employing the basic ideas and principles of sampling to teach students to understand and recognize its role in statistical claims. Emphasizes estimation, data analysis and interpretation, and central limit theorem. Includes a list of items for classroom discussion. (ASK)

  19. RBC count

    MedlinePlus

    ... Drugs that can increase the RBC count include: Gentamicin Methyldopa Lower-than-normal numbers of RBCs may be due to: Anemia Bleeding Bone marrow failure (for example, from radiation, toxins, or tumor) Deficiency of a hormone called erythropoietin (caused by ...

  20. Counting Populations

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    Scientists use sampling to get an estimate of things they cannot easily count. A population is made up of all the organisms of one species living together in one place at the same time. All of the people living together in one town are considered a population. All of the grasshoppers living in a field are a population. Scientists keep track of the…

  1. Death rates in HIV-positive antiretroviral-naive patients with CD4 count greater than 350 cells per microL in Europe and North America: a pooled cohort observational study

    PubMed Central

    2011-01-01

    Background It is unclear whether antiretroviral (ART) naive HIV-positive individuals with high CD4 counts have a raised mortality risk compared with the general population, but this is relevant for considering earlier initiation of antiretroviral therapy. Methods Pooling data from 23 European and North American cohorts, we calculated country-, age-, sex-, and year-standardised mortality ratios (SMRs), stratifying by risk group. Included patients had at least one pre-ART CD4 count above 350 cells/mm3. The association between CD4 count and death rate was evaluated using Poisson regression methods. Findings Of 40,830 patients contributing 80,682 person-years of follow up with CD4 count above 350 cells/mm3, 419 (1.0%) died. The SMRs (95% confidence interval) were 1.30 (1.06-1.58) in homosexual men, and 2.94 (2.28-3.73) and 9.37 (8.13-10.75) in the heterosexual and IDU risk groups respectively. CD4 count above 500 cells/mm3 was associated with a lower death rate than 350-499 cells/mm3: adjusted rate ratios (95% confidence intervals) for 500-699 cells/mm3 and above 700 cells/mm3 were 0.77 (0.61-0.95) and 0.66 (0.52-0.85) respectively. Interpretation In HIV-infected ART-naive patients with high CD4 counts, death rates were raised compared with the general population. In homosexual men this was modest, suggesting that a proportion of the increased risk in other groups is due to confounding by other factors. Even in this high CD4 count range, lower CD4 count was associated with raised mortality. PMID:20638118

  2. A Study of the Associations between Conditions of Performance and Characteristics of Performers and New York State Solo Performance Ratings

    ERIC Educational Resources Information Center

    vonWurmb, Elizabeth C.

    2013-01-01

    This dissertation undertakes an analysis of 1,044 performance evaluations from New York State School Music Association (NYSSMA) Spring Festival solo adjudication ratings of student performers from a large suburban school district. It relies on results of evaluations of observed performances, and takes these evaluations as assessments of what the…

  3. The effect of relative update rates on tracking performance

    NASA Astrophysics Data System (ADS)

    Rea, Charles; Silbert, Mark

    2011-06-01

    In multi-sensor fusion applications, various sources of data are combined to create a coherent situational picture. The ability to track multiple targets using multiple sensors is an important problem. The data provided by these sensors can be of varying quality, such as data from RADAR and AIS. Does this varied quality of data negatively impact the tracking performance when compared to using the best data source alone? From an information-theoretic standpoint, the answer would be no. However, this paper investigates this issue and exposes a few caveats. In particular, this study addresses how the relative update rate of varying quality sensors affects tracking performance and answers the question 'Is more data always better?'

  4. Correlation between heart rate and performance during Olympic windsurfing competition.

    PubMed

    Chamari, Karim; Moussa-Chamari, Imen; Galy, Olivier; Chaouachi, Mustapha; Koubaa, Donia; Hassen, Chokri Ben; Hue, Olivier

    2003-05-01

    The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (.VO(2max)) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HR(max) (maximal treadmill HR) and (2) HR(reserve) (HR(max)-HR(rest)). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW-RC=-0.12(%HR(reserve))+13.03; r=-0.71, r(2)=0.50, p<0.001, and medium wind (MW): MW-RC=-0.11(%HR(reserve))+10.99; r=-0.66, r(2)=0.43, p<0.001. The results showed similar correlations between performance and %HR(max). Post racing lactate concentration was higher in LW compared to MW [7.14 (0.21) and 5.18 (2.02) mmol.l(-1), respectively]. There was a negative correlation between the highest racing HR (%HR(reserve)) of each athlete and the second ventilatory threshold expressed as a percentage of .VO(2max) ( r=-0.71, p<0.05). To summarize, this study showed that light and medium wind Olympic windsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables. PMID:12682836

  5. Impact performance of FRC slabs under various strain rates

    NASA Astrophysics Data System (ADS)

    Horska, Alena; Jiricek, Pavel; Foglar, Marek

    2015-09-01

    Impact resistance of plain concrete and FRC composites gains high importance in the present days. This paper presents outcomes of the experiments focused on performance of FRC slabs subjected to impact loading of various strain rates. The FRC slabs, thickness 30, 60 and 120 mm were subjected to various drop-weight impacts. The different drop-hammer weights provided different loading speeds and strain rates. The performance of the slabs was recorded with the use of high speed cameras. The cameras were used for impact speed control and specimen deflection measurement. With the use of the recordings, the force-time response of the slabs could be plotted. The plots correspond to the mechanical behaviour obtained by static load tests (loading speed 0.2 mm/min) but several differences can be found. Several types of FRC (varying fiber material, fiber content, etc.) were tested and evaluated. The experimental program is supplemented by numerical modelling which provides good agreement with the experimental results.

  6. High-performance micromachined vibratory rate- and rate-integrating gyroscopes

    NASA Astrophysics Data System (ADS)

    Cho, Jae Yoong

    The performance of vibratory micromachined gyroscopes has been continuously improving for the past two decades. However, to further improve performance of the MEMS gyroscope in harsh environment, it is necessary for gyros to reduce the sensitivity to environmental parameters, including vibration and temperature change. In addition, conventional rate-mode MEMS gyroscopes have limitation in performance due to tradeoff between resolution, bandwidth, and full-scale range. In this research, we aim to reduce vibration sensitivity by developing gyros that operate in the balanced mode. The balanced mode creates zero net momentum and reduces energy loss through an anchor. The gyro can differentially cancel measurement errors from external vibration along both sensor axes. The vibration sensitivity of the balanced-mode gyroscope including structural imbalance from microfabrication reduces as the absolute difference between in-phase parasitic mode and operating mode frequencies increases. The parasitic sensing mode frequency is designed larger than the operating mode frequency to achieve both improved vibration insensitivity and shock resistivity. A single anchor is used in order to minimize thermoresidual stress change. We developed two gyroscope based on these design principles. The Balanced Oscillating Gyro (BOG) is a quad-mass tuning-fork rate gyroscope. The relationship between gyro design and modal characteristics is studied extensively using finite element method (FEM). The gyro is fabricated using the planar Si-on-glass (SOG) process with a device thickness of 100microm. The BOG is evaluated using the first-generation analog interface circuitry. Under a frequency mismatch of 5Hz between driving and sense modes, the angle random walk (ARW) is measured to be 0.44°/sec/✓Hz. The performance is limited by quadrature error and low-frequency noise in the circuit. The Cylindrical Rate-Integrating Gyroscope (CING) operates in whole-angle mode. The gyro is completely

  7. Reticulocyte Count Test

    MedlinePlus

    ... Reticulocyte Count Related tests: Red Blood Cell Count ; Hemoglobin ; Hematocrit ; Complete Blood Count ; Blood Smear ; Erythropoietin ; Vitamin ... on a complete blood count (CBC) , RBC count , hemoglobin or hematocrit , to help determine the cause To ...

  8. White Blood Cell Count

    MedlinePlus

    ... Home Visit Global Sites Search Help? White Blood Cell Count Share this page: Was this page helpful? Also ... Leukocyte Count; White Count Formal name: White Blood Cell Count Related tests: Complete Blood Count , Blood Smear , White ...

  9. Dietary β-glucan improved growth performance, Vibrio counts, haematological parameters and stress resistance of pompano fish, Trachinotus ovatus Linnaeus, 1758.

    PubMed

    Do Huu, Hoang; Sang, Huynh Minh; Thanh Thuy, Nguyen Thi

    2016-07-01

    This study evaluated effects of graded levels of dietary β-glucan (0, 0.5, 1, 2 and 4 g kg(-1)) on growth performance, haematological parameters, intestinal Vibrio counts, dose requirement and salinity stress resistance in pompano fish Trachinotus ovatus (6.45 g ± 0.06 (SEM)). After 8-weeks of diet feeding, growth was significantly higher in fish fed diets with 0.10% β-glucan compared to fish fed control diet (no β-glucan). Survival increased significantly in fish fed 0.05 and 0.10% β-glucan compared to control diet. There were significant increases in red blood cells (in 0.20% β-glucan diet), in total leukocytes (in 0.05-0.20% β-glucan diet), in both lymphocyte and monocyte count in fish fed 0.10%-0.40% β-glucan diet. However, dietary β-glucan did not affect neutrophil, eosinophil and basophil counts. Intestinal Vibrio counts were reduced in fish fed any level of β-glucan compared to control. In addition, dietary β-glucan levels highly correlated with growth, survival, intestinal Vibrio counts and haematological index. Optimal β-glucan levels for maximal growth of fish were predicted to be 0.122% at day 21 (R(2) = 98.53%), 0.120% at day 28 (R(2) = 78.55%), 0.115% at day 42 (R(2) = 62.21%) and 0.090% at day 56 (R(2) = 75.18%), showing a decreasing β-glucan requirement with increasing fish size. Furthermore, optimal β-glucan levels for maximal haematological parameters based on lymphocyte count, was estimated to be 0.120% (R(2) = 98.53%) at day 56. Also, fish fed 0.05%-0.20% β-glucan showed better resistance against salinity stress. In conclusion, β-glucan supplementation is effective for improving growth, intestinal Vibrio counts and boosted stress resistance of the pompano fish, T. ovatus. PMID:27036404

  10. Pseudo-random single photon counting: a high-speed implementation

    PubMed Central

    Zhang, Qiang; Chen, Ling; Chen, Nanguang

    2010-01-01

    Pseudo-random single photon counting (PRSPC) is a new time-resolved optical measurement method which combines the spread spectrum time-resolved method with single photon counting. A pseudo-random bit sequence is used to modulate a continuous wave laser diode, while single photon counting is used to build up the optical signal in response to the modulated excitation. Periodic cross-correlation is performed to obtain the temporal profile of the subject of interest. Compared with conventional time-correlated single photon counting (TCSPC), PRSPC enjoys many advantages such as low cost and high count rate without compromising the sensitivity and time-resolution. In this paper, we report a PRSPC system that can be used for high-speed acquisition of the temporal point spread function of diffuse photons. It can reach a photon count rate as high as 3 Mcps (counts per second). Phantom experiments have been conducted to demonstrate the system performance. PMID:21258444

  11. Photon counting digital holography

    NASA Astrophysics Data System (ADS)

    Demoli, Nazif; Skenderović, Hrvoje; Stipčević, Mario; Pavičić, Mladen

    2016-05-01

    Digital holography uses electronic sensors for hologram recording and numerical method for hologram reconstruction enabling thus the development of advanced holography applications. However, in some cases, the useful information is concealed in a very wide dynamic range of illumination intensities and successful recording requires an appropriate dynamic range of the sensor. An effective solution to this problem is the use of a photon-counting detector. Such detectors possess counting rates of the order of tens to hundreds of millions counts per second, but conditions of recording holograms have to be investigated in greater detail. Here, we summarize our main findings on this problem. First, conditions for optimum recording of digital holograms for detecting a signal significantly below detector's noise are analyzed in terms of the most important holographic measures. Second, for time-averaged digital holograms, optimum recordings were investigated for exposures shorter than the vibration cycle. In both cases, these conditions are studied by simulations and experiments.

  12. Accounting for What Counts

    ERIC Educational Resources Information Center

    Milner, Joseph O.; Ferran, Joan E.; Martin, Katharine Y.

    2003-01-01

    No Child Left Behind legislation makes it clear that outside evaluators determine what gets taught in the classroom. It is important to ensure they measure what truly counts in school. This fact is poignantly and sadly true for the under funded, poorly resourced, "low performing" schools that may be hammered by administration accountants in the…

  13. Carica papaya Leaves Juice Significantly Accelerates the Rate of Increase in Platelet Count among Patients with Dengue Fever and Dengue Haemorrhagic Fever.

    PubMed

    Subenthiran, Soobitha; Choon, Tan Chwee; Cheong, Kee Chee; Thayan, Ravindran; Teck, Mok Boon; Muniandy, Prem Kumar; Afzan, Adlin; Abdullah, Noor Rain; Ismail, Zakiah

    2013-01-01

    The study was conducted to investigate the platelet increasing property of Carica papaya leaves juice (CPLJ) in patients with dengue fever (DF). An open labeled randomized controlled trial was carried out on 228 patients with DF and dengue haemorrhagic fever (DHF). Approximately half the patients received the juice, for 3 consecutive days while the others remained as controls and received the standard management. Their full blood count was monitored 8 hours for 48 hours. Gene expression studies were conducted on the ALOX 12 and PTAFR genes. The mean increase in platelet counts were compared in both groups using repeated measure ANCOVA. There was a significant increase in mean platelet count observed in the intervention group (P < 0.001) but not in the control group 40 hours since the first dose of CPLJ. Comparison of mean platelet count between intervention and control group showed that mean platelet count in intervention group was significantly higher than control group after 40 and 48 hours of admission (P < 0.01). The ALOX 12 (FC  =  15.00) and PTAFR (FC  =  13.42) genes were highly expressed among those on the juice. It was concluded that CPLJ does significantly increase the platelet count in patients with DF and DHF. PMID:23662145

  14. Counting every quantum

    PubMed Central

    Sakitt, B.

    1972-01-01

    1. Human subjects were asked to rate both blanks and very dim flashes of light under conditions of complete dark adaptation at 7° in the periphery. The ratings used were 0, 1, 2, 3, 4, 5, and 6. 2. For one subject (B.S.) the distributions of ratings were approximately Poisson distributions. The data were consistent with each rating being the actual number of effective quantal absorptions plus the number of noise events. This subject was presumably able to count every rod signal (effective absorptions plus noise). 3. For two other subjects, the data were consistent with the ratings being one less (L.F.) and two less (K.D.) than the number of effective absorptions plus noise. They were able to count every rod signal beginning with 2 and 3 respectively. A fourth subject's erratic data could not be fitted. 4. The fraction of quanta incident at the cornea that resulted in a rod signal was estimated to be about 0·03 which is consistent with physical estimates of effective absorption for that retinal region. 5. A simulated forced choice experiment leads to an absolute threshold about 0·40 log units below the normal yes-no absolute threshold. This and other results indicate that subjects can use the sensory information they receive even when only 1, 2 or 3 quanta are effectively absorbed, depending on the individual. Humans may be able to count every action potential or every discrete burst of action potentials in some critical neurone. PMID:5046137

  15. Effects of task performance, helping, voice, and organizational loyalty on performance appraisal ratings.

    PubMed

    Whiting, Steven W; Podsakoff, Philip M; Pierce, Jason R

    2008-01-01

    Despite the fact that several studies have investigated the relationship between organizational citizenship behavior and performance appraisal ratings, the vast majority of these studies have been cross-sectional, correlational investigations conducted in organizational settings that do not allow researchers to establish the causal nature of this relationship. To address this lack of knowledge regarding causality, the authors conducted 2 studies designed to investigate the effects of task performance, helping behavior, voice, and organizational loyalty on performance appraisal evaluations. Findings demonstrated that each of these forms of behavior has significant effects on performance evaluation decisions and suggest that additional attention should be directed at both voice and organizational loyalty as important forms of citizenship behavior aimed at the organization. PMID:18211140

  16. Transfer Rates and Academic Performance of Delta College Students.

    ERIC Educational Resources Information Center

    Evans, John W.

    In an effort to define and test a practical methodology to measure community college transfer rates, the California College Chief Executive Officers commissioned the California Transfer Rate Study (CTRS). The CTRS calculated transfer rates for 65 participating community colleges by measuring the number of exiting students (i.e., not returning for…

  17. Attentional Focus and Performance Anxiety: Effects on Simulated Race-Driving Performance and Heart Rate Variability

    PubMed Central

    Mullen, Richard; Faull, Andrea; Jones, Eleri S.; Kingston, Kieran

    2012-01-01

    Previous studies have demonstrated that an external focus can enhance motor learning compared to an internal focus. The benefits of adopting an external focus are attributed to the use of less effortful automatic control processes, while an internal focus relies upon more effort-intensive consciously controlled processes. The aim of this study was to compare the effectiveness of a distal external focus with an internal focus in the acquisition of a simulated driving task and subsequent performance in a competitive condition designed to increase state anxiety. To provide further evidence for the automatic nature of externally controlled movements, the study included heart rate variability (HRV) as an index of mental effort. Sixteen participants completed eight blocks of four laps in either a distal external or internal focus condition, followed by two blocks of four laps in the competitive condition. During acquisition, the performance of both groups improved; however, the distal external focus group outperformed the internal focus group. The poorer performance of the internal focus group was accompanied by a larger reduction in HRV, indicating a greater investment of mental effort. In the competition condition, state anxiety increased, and for both groups, performance improved as a function of the increased anxiety. Increased heart rate and self-reported mental effort accompanied the performance improvement. The distal external focus group also outperformed the internal focus group across both neutral and competitive conditions and this more effective performance was again associated with lower levels of HRV. Overall, the results offer support for the suggestion that an external focus promotes a more automatic mode of functioning. In the competitive condition, both foci enhanced performance and while the improved performance may have been achieved at the expense of greater compensatory mental effort, this was not reflected in HRV scores. PMID:23133431

  18. Evaluation of a semi-automated platelet-counting system.

    PubMed

    Rowan, R M; Fraser, C; Gray, J H; McDonald, G A

    1977-04-01

    Coulter Electronics Ltd have produced a semi-automated platelet-counting system. Platelet-rich plasma may be obtained either by tube sedimentation or by means of the Thrombo-fuge, the latter being an instrument designed to produce accelerated sedimentation. The instrument is linear over the entire range of platelet counts, and machine reproducibility is good. Comparison of machine-rated with visual counts satisfied statistical evaluation. The technique can be handled by one operator and platelet counts can be achieved at the rate of 30 per hour by both methods although individual counts on the Thrombo-fuge may be obtained in approximately one-quarter of the time required for tube sedimentation. The throughput using the Thrombo-fuge could certainly be doubled were two sample plates supplied. Few problems were encountered during the evaluation and most could be avoided by meticulous technique. Visual counts must be performed when the sample haematocrit is greater than 50%-Discrepant counts have been obtained in patients with white cell counts exceeding 50 X 10(9)/1 and in patients with giant platelets. ESR elevation for any reason does not lead to serious discrepancy in results. The incidence of platelet clumping due to the presence of platelet agglutinins and of microclot formation due to inadequate mixing is probably much higher than is commonly thought, and certainly peripheral blood film scrutiny should never be omitted in patients with low counts. Careful examination of peripheral blood films must be combined with instrument counting for some time lest further causes of discrepant counting emerge. PMID:856881

  19. Background Factors Predicting Teacher Ratings of Children's School Performance.

    ERIC Educational Resources Information Center

    Kerr, M. Kaye

    This study examined background factors in children that influence teachers' ratings on the Classroom Adjustment Rating Scale (CARS). Sixteen classrooms in five schools were selected to include a range of socio-economic and cultural groupings from Inner London, England Primary Schools. Teachers used the CARS and an additional short scale of overall…

  20. Performance evaluation of a center pivot variable rate irrigation system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variable Rate Irrigation (VRI) for center pivots offers potential to match specific application rates to non-uniform soil conditions along the length of the lateral. The benefit of such systems is influenced by the areal extent of these variations and the smallest scale to which the irrigation syste...

  1. Sensitivity of School-Performance Ratings to Scaling Decisions

    ERIC Educational Resources Information Center

    Ng, Hui Leng; Koretz, Daniel

    2015-01-01

    Policymakers usually leave decisions about scaling the scores used for accountability to their appointed technical advisory committees and the testing contractors. However, scaling decisions can have an appreciable impact on school ratings. Using middle-school data from New York State, we examined the consistency of school ratings based on two…

  2. Effect of processing rate on seed cotton cleaning equipment performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The processing rate per unit width of seed cotton cleaning equipment– cylinder cleaners and stick machines– recommended by manufacturers is 4.8-8.2 bales hr-1 m-1 (1.5-2.5 bales hr-1 ft-1). Survey data has indicated that many gins exceed this processing rate. Previous research with picker-harvested ...

  3. Imaging performance comparison between a LaBr3: Ce scintillator based and a CdTe semiconductor based photon counting compact gamma camera.

    PubMed

    Russo, P; Mettivier, G; Pani, R; Pellegrini, R; Cinti, M N; Bennati, P

    2009-04-01

    The authors report on the performance of two small field of view, compact gamma cameras working in single photon counting in planar imaging tests at 122 and 140 keV. The first camera is based on a LaBr3: Ce scintillator continuous crystal (49 x 49 x 5 mm3) assembled with a flat panel multianode photomultiplier tube with parallel readout. The second one belongs to the class of semiconductor hybrid pixel detectors, specifically, a CdTe pixel detector (14 x 14 x 1 mm3) with 256 x 256 square pixels and a pitch of 55 microm, read out by a CMOS single photon counting integrated circuit of the Medipix2 series. The scintillation camera was operated with selectable energy window while the CdTe camera was operated with a single low-energy detection threshold of about 20 keV, i.e., without energy discrimination. The detectors were coupled to pinhole or parallel-hole high-resolution collimators. The evaluation of their overall performance in basic imaging tasks is presented through measurements of their detection efficiency, intrinsic spatial resolution, noise, image SNR, and contrast recovery. The scintillation and CdTe cameras showed, respectively, detection efficiencies at 122 keV of 83% and 45%, intrinsic spatial resolutions of 0.9 mm and 75 microm, and total background noises of 40.5 and 1.6 cps. Imaging tests with high-resolution parallel-hole and pinhole collimators are also reported. PMID:19472638

  4. Analysis of calibration data for the uranium active neutron coincidence counting collar with attention to errors in the measured neutron coincidence rate

    NASA Astrophysics Data System (ADS)

    Croft, Stephen; Burr, Tom; Favalli, Andrea; Nicholson, Andrew

    2016-03-01

    The declared linear density of 238U and 235U in fresh low enriched uranium light water reactor fuel assemblies can be verified for nuclear safeguards purposes using a neutron coincidence counter collar in passive and active mode, respectively. The active mode calibration of the Uranium Neutron Collar - Light water reactor fuel (UNCL) instrument is normally performed using a non-linear fitting technique. The fitting technique relates the measured neutron coincidence rate (the predictor) to the linear density of 235U (the response) in order to estimate model parameters of the nonlinear Padé equation, which traditionally is used to model the calibration data. Alternatively, following a simple data transformation, the fitting can also be performed using standard linear fitting methods. This paper compares performance of the nonlinear technique to the linear technique, using a range of possible error variance magnitudes in the measured neutron coincidence rate. We develop the required formalism and then apply the traditional (nonlinear) and alternative approaches (linear) to the same experimental and corresponding simulated representative datasets. We find that, in this context, because of the magnitude of the errors in the predictor, it is preferable not to transform to a linear model, and it is preferable not to adjust for the errors in the predictor when inferring the model parameters.

  5. Ratings of Residents' Clinical Competence and Performance on Certification Examination.

    ERIC Educational Resources Information Center

    Norcinin, John J.; And Others

    1987-01-01

    A study of the correlation between certification test results and ratings of clinical competence for graduate medical students in internal medicine during a six-year period found strong correlations on both individual and general indicators of competence. (MSE)

  6. Conversation Counts.

    PubMed

    Sorrel, Amy Lynn

    2016-03-01

    Informed consent is a hallmark of good old-fashioned patient care. But some Texas physicians and hospitals are finding ways to use the process as an opportunity to improve patient safety and patient-centered care. The Texas Medical Disclosure Panel - the state regulatory body overseeing informed consent for medical treatments - is taking steps to make state forms even more understandable for patients at a time when health literacy rates are low. PMID:26928817

  7. Student Assessment and Performance. Measuring Up: The State of Texas Education. A Special Report of the Texas Kids Count Project.

    ERIC Educational Resources Information Center

    Texas Kids Count Project, Austin.

    This report focuses on the standards and test schools used to measure student and school performance in Texas. The primary method for evaluating the academic achievement of Texas public school students is a standardized test called the Texas Assessment of Academic Skills (TAAS). A review of TAAS scores and their uses suggests that the TAAS test…

  8. Modeling the Effects of Transmission Type, Gear Count and Ratio Spread on Fuel Economy and Performance Using ALPHA

    EPA Science Inventory

    This paper presents an analysis of the effects of varying the absolute and relative gear ratios of a given transmission on fuel economy and performance, considers alternative methods of selecting absolute gear ratios, examines the effect of alternative engines on the selections o...

  9. 12 CFR 563e.21 - Performance tests, standards, and ratings, in general.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Performance tests, standards, and ratings, in... TREASURY COMMUNITY REINVESTMENT Standards for Assessing Performance § 563e.21 Performance tests, standards, and ratings, in general. (a) Performance tests and standards. The OTS assesses the CRA performance...

  10. Lung counting: Comparison of a four detector array that has either metal or carbon fiber end caps, and the effect on array performance characteristics

    NASA Astrophysics Data System (ADS)

    Sabbir Ahmed, Asm; H. Kramer, Gary

    2011-12-01

    This study described the performance of an array of HPGe detectors, made by ORTEC. In the existing system, a metal end cap was used in the detector construction. In general, the natural metal contains some radioactive materials, create high background noises and signals during in vivo counting. ORTEC proposed a novel carbon fiber to be used in end cap, without any radio active content. This paper described the methodology of developing a model of the given HPGe array-detectors, comparing the detection efficiency and cross talk among the detectors using two end cap materials: either metal or carbon fiber and to provide a recommendation about the end cap material. The detector's counting efficiency were studied using point and plane sources. The cross talk among the array detectors were studied using a homogeneous attenuating medium made of tissue equivalent material. The cross talk was significant when single or multiple point sources (simulated to heterogeneous hot spots) were embedded inside the attenuating medium. With carbon fiber, the cross talk increased about 100% for photon energy at about 100 keV. For a uniform distribution of radioactive material, the cross talk increased about 5-10% when the end cap was made of carbon instead of steel. Metal end cap was recommended for the array of HPGe detectors.

  11. Dual-energy performance of dual kVp in comparison to dual-layer and quantum-counting CT system concepts

    NASA Astrophysics Data System (ADS)

    Kappler, S.; Grasruck, M.; Niederlöhner, D.; Strassburg, M.; Wirth, S.

    2009-02-01

    Recent publications in the field of Computed Tomography (CT) demonstrate the rising interest in applying dual-energy methods for material classification during clinical routine examinations. Based on today's standard of technology, dual-energy CT can be realized by either scanning with different X-ray spectra or by deployment of energy selective detector technologies. The list of so-called dual-kVp methods contains sequential scans, fast kVp-switching and dual-source CT. Examples of energy selective detectors are scintillator-based energyintegrating dual-layer devices or direct converter with quantum counting electronics. The general difference of the approaches lies in the shape of the effectively detected X-ray energy spectra and in the presence of crossscatter radiation in the case of dual-source devices. This leads to different material classification capabilities for the various techniques. In this work, we present detector response simulations of realistic CT scans with subsequent CT image reconstruction. Analysis of the image data allows direct and objective comparison of the dual-kVp, dual-layer, and quantum counting CT system concepts. The dual-energy performance is benchmarked in terms of image noise and Iodine-bone separation power at given image sharpness and dose exposure. For the case of dual-source devices the effect of cross-scatter radiation, as well as the benefit of additional filtering are taken into account.

  12. Kids Count Data Sheet, 2000.

    ERIC Educational Resources Information Center

    Annie E. Casey Foundation, Baltimore, MD.

    Data from the 50 United States are listed for 1997 from Kids Count in an effort to track state-by-state the status of children in the United States and to secure better futures for all children. Data include percent low birth weight babies; infant mortality rate; child death rate; rate of teen deaths by accident, homicide, and suicide; teen birth…

  13. Temporal Coordination and Adaptation to Rate Change in Music Performance

    ERIC Educational Resources Information Center

    Loehr, Janeen D.; Large, Edward W.; Palmer, Caroline

    2011-01-01

    People often coordinate their actions with sequences that exhibit temporal variability and unfold at multiple periodicities. We compared oscillator- and timekeeper-based accounts of temporal coordination by examining musicians' coordination of rhythmic musical sequences with a metronome that gradually changed rate at the end of a musical phrase…

  14. Building Fluent Performance: Measuring Response Rate and Multiplying Response Opportunities

    ERIC Educational Resources Information Center

    Binder, Carl

    2010-01-01

    Precision teaching emerged from O.R. Lindsley's pristine application of Skinner's natural science of behavior, with a focus on response rate measurement and free operant procedures. When applied with human learners in instructional settings, these first principles led to a series of developments framed in this paper as four kinds of ceilings that…

  15. Effects of Professorial Tenure on Undergraduate Ratings of Teaching Performance

    ERIC Educational Resources Information Center

    Cheng, Dorothy A.

    2015-01-01

    This study estimates the effect of professorial tenure on undergraduate ratings of learning, instructor quality, and course quality at the University of California, San Diego from Summer 2004 to Spring 2012. During this eight-year period, 120 assistant professors received tenure and 83 associate professors attained full rank. A…

  16. Machiavellianism scores and self-rated performance of automobile salespersons.

    PubMed

    Aziz, Abdul

    2004-04-01

    Machiavellianism (Mach-B) was positively correlated with self-reported number of vehicles sold and income in two samples of 80 car salespersons. The Mach-B scale showed higher internal consistency and significant relationship with sales performance. The Mach IV scale, used for one of two samples, showed low internal consistency and a nonsignificant relationship with performance. The results provided partial support for earlier findings. Research designed to clarify this finding is required. PMID:15154173

  17. 29 CFR 778.311 - Flat rate for special job performed in overtime hours.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Flat rate for special job performed in overtime hours. 778... COMPENSATION Special Problems Lump Sum Attributed to Overtime § 778.311 Flat rate for special job performed in... paid a flat rate for a special job performed during overtime hours, without regard to the time...

  18. 29 CFR 778.311 - Flat rate for special job performed in overtime hours.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Flat rate for special job performed in overtime hours. 778... COMPENSATION Special Problems Lump Sum Attributed to Overtime § 778.311 Flat rate for special job performed in... paid a flat rate for a special job performed during overtime hours, without regard to the time...

  19. 29 CFR 778.311 - Flat rate for special job performed in overtime hours.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Flat rate for special job performed in overtime hours. 778... COMPENSATION Special Problems Lump Sum Attributed to Overtime § 778.311 Flat rate for special job performed in... paid a flat rate for a special job performed during overtime hours, without regard to the time...

  20. 29 CFR 778.311 - Flat rate for special job performed in overtime hours.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Flat rate for special job performed in overtime hours. 778... COMPENSATION Special Problems Lump Sum Attributed to Overtime § 778.311 Flat rate for special job performed in... paid a flat rate for a special job performed during overtime hours, without regard to the time...

  1. 29 CFR 778.311 - Flat rate for special job performed in overtime hours.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Flat rate for special job performed in overtime hours. 778... COMPENSATION Special Problems Lump Sum Attributed to Overtime § 778.311 Flat rate for special job performed in... paid a flat rate for a special job performed during overtime hours, without regard to the time...

  2. Improving Student Performance Outcomes and Graduation Rates through Institutional Partnerships

    ERIC Educational Resources Information Center

    Roggow, Michael J.

    2014-01-01

    This chapter explores a grant-sponsored program and examines the role of departmental and institutional collaborations in advancing student performance outcomes. It provides a theoretical framework and a description of best practices for ensuring the success of first-generation urban community college students.

  3. On-Line Performance Assessment Using Rating Scales.

    ERIC Educational Resources Information Center

    Stahl, John; Shumway, Rebecca; Bergstrom, Betty; Fisher, Anne

    1997-01-01

    The development of an online performance assessment instrument, the Assessment of Motor and Process Skills, is reported. Issues addressed include development, implementation, and validation of the scoring rubric in an extended Rasch model, rater training, and implementation of the assessment in a computerized program. (SLD)

  4. Teacher Performance Assessment Instruments: Plans for Practice Rating.

    ERIC Educational Resources Information Center

    Capie, William; And Others

    This manual consists of lesson plans developed to train data collectors in the use of the Teacher Performance Assessment Instruments (TPAI). Each set of plans was designed for one of three purposes. Lesson plans developed for the Teaching Plans and Materials Instrument (TPM) simulate a portfolio prepared by the teacher. One-day plans developed for…

  5. Rating Written Performance: What Do Raters Do and Why?

    ERIC Educational Resources Information Center

    Kuiken, Folkert; Vedder, Ineke

    2014-01-01

    This study investigates the relationship in L2 writing between raters' judgments of communicative adequacy and linguistic complexity by means of six-point Likert scales, and general measures of linguistic performance. The participants were 39 learners of Italian and 32 of Dutch, who wrote two short argumentative essays. The same writing tasks…

  6. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... § 9701.342(a); (4) A within-grade increase determination under 5 CFR 531.404, prior to conversion to the... applicable pay rules; (6) Awards under any legal authority, including 5 U.S.C. chapter 45, 5 CFR part 451... performance. Such policies must comply with 5 U.S.C. chapter 35 and 5 CFR 351.504....

  7. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... § 9701.342(a); (4) A within-grade increase determination under 5 CFR 531.404, prior to conversion to the... applicable pay rules; (6) Awards under any legal authority, including 5 U.S.C. chapter 45, 5 CFR part 451... performance. Such policies must comply with 5 U.S.C. chapter 35 and 5 CFR 351.504....

  8. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... § 9701.342(a); (4) A within-grade increase determination under 5 CFR 531.404, prior to conversion to the... applicable pay rules; (6) Awards under any legal authority, including 5 U.S.C. chapter 45, 5 CFR part 451... performance. Such policies must comply with 5 U.S.C. chapter 35 and 5 CFR 351.504....

  9. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... § 9701.342(a); (4) A within-grade increase determination under 5 CFR 531.404, prior to conversion to the... applicable pay rules; (6) Awards under any legal authority, including 5 U.S.C. chapter 45, 5 CFR part 451... performance. Such policies must comply with 5 U.S.C. chapter 35 and 5 CFR 351.504....

  10. Imaging performance comparison between a LaBr{sub 3}:Ce scintillator based and a CdTe semiconductor based photon counting compact gamma camera

    SciTech Connect

    Russo, P.; Mettivier, G.; Pani, R.; Pellegrini, R.; Cinti, M. N.; Bennati, P.

    2009-04-15

    The authors report on the performance of two small field of view, compact gamma cameras working in single photon counting in planar imaging tests at 122 and 140 keV. The first camera is based on a LaBr{sub 3}:Ce scintillator continuous crystal (49x49x5 mm{sup 3}) assembled with a flat panel multianode photomultiplier tube with parallel readout. The second one belongs to the class of semiconductor hybrid pixel detectors, specifically, a CdTe pixel detector (14x14x1 mm{sup 3}) with 256x256 square pixels and a pitch of 55 {mu}m, read out by a CMOS single photon counting integrated circuit of the Medipix2 series. The scintillation camera was operated with selectable energy window while the CdTe camera was operated with a single low-energy detection threshold of about 20 keV, i.e., without energy discrimination. The detectors were coupled to pinhole or parallel-hole high-resolution collimators. The evaluation of their overall performance in basic imaging tasks is presented through measurements of their detection efficiency, intrinsic spatial resolution, noise, image SNR, and contrast recovery. The scintillation and CdTe cameras showed, respectively, detection efficiencies at 122 keV of 83% and 45%, intrinsic spatial resolutions of 0.9 mm and 75 {mu}m, and total background noises of 40.5 and 1.6 cps. Imaging tests with high-resolution parallel-hole and pinhole collimators are also reported.

  11. The role of the Internet in doctor performance rating.

    PubMed

    Segal, Jeffrey

    2009-01-01

    Historically, if a patient was dissatisfied with care, he or she could tell his or her friends and family. The criticism was limited to a small circle of people. If the patient was injured negligently, he or she could hire an attorney to prosecute a lawsuit. The threshold for finding an attorney and prevailing posed a significant barrier for the patient achieving redress. With the Internet, if a patient is unhappy he or she needs do little more than access a growing number of Internet physician rating sites. Such criticism can be rendered anonymously. The posts are disseminated worldwide, and once posted, the criticism rarely comes down. While transparency is a laudable goal, such sites often lack accountability. More formal sites run by authoritative bodies, such as medical licensing boards, also provide data about physicians, but such data is often unfiltered, making it difficult for the public to properly interpret. Given how important reputation is to physicians, the traditional remedy of suing for defamation because of libelous posts is ordinarily ineffective. First, many patients who post libelous comments, do so anonymously. Next, the Internet Service Providers (ISPs) hosting such sites are generally immune from liability for defamation. Finally, the law has a very formal definition for libel, and a negative rating does not necessarily equate to "defamation." A novel method of addressing un-policed physician rating sites in the Internet age is described. The system embraces the use of mutual privacy contracts to provide physicians a viable remedy to anonymous posts. In exchange, patients receive additional privacy protections above and beyond that mandated by law. PMID:19461833

  12. Eosinophil count - absolute

    MedlinePlus

    Eosinophils; Absolute eosinophil count ... the white blood cell count to give the absolute eosinophil count. ... than 500 cells per microliter (cells/mcL). Normal value ranges may vary slightly among different laboratories. Talk ...

  13. 12 CFR 195.21 - Performance tests, standards, and ratings, in general.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Performance tests, standards, and ratings, in general. 195.21 Section 195.21 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY COMMUNITY REINVESTMENT Standards for Assessing Performance § 195.21 Performance tests, standards, and ratings, in general. (a) Performance...

  14. Effects of different floor types and levels of washing of waterers on broiler performance and bacteria count of drinking water.

    PubMed

    Andrews, L D; Stamps, L K; Moore, R W; Newberry, L A

    1993-07-01

    The objective of the present experiment was to determine the effect of different flooring materials and washing of waterers on broiler performance. The floor treatments were 1) black, plastic-coated expanded metal, relatively rigid (B); 2) white plastic, semi-rigid, with rectangular openings (WR); 3) white plastic, semi-rigid, with square openings (WS); and 4) 3 cm of rice hull litter (C). One hanging waterer was placed in each pen. Wash treatments were 1) trough and bell washed every Monday, Wednesday, and Friday (AW); 2) wash trough only on Monday, Wednesday, and Friday (TW); and 3) the waterers were never washed after the 2nd wk (NW). Broilers reared on C has significantly lower BW than those broilers on B floors. Broilers reared on the B and WS floors had significantly higher breast blister scores and percentage of birds with blisters than broilers reared on C floors. Broilers reared on C had lower enlarged feather follicle scores than those reared on all raised floors and a lower percentage of enlarged feather follicles than those broilers reared on WS or WR floors. Broilers reared on WS+TW had significantly better feed conversion than WS+AW, B+TW, and B+AW treatments. Broilers reared on WR+TW treatment were significantly higher in breast blister score than broilers reared on WR+AW, C+TW, and C+AW treatments. Broilers reared on C+TW and C+AW treatments were significantly lower in breast blister score except for broilers reared on C+NW, WR+AW, and WS+AW treatments. Broilers reared on C+NW treatment were significantly lower in enlarged feather follicle score than those broilers reared on B+TW, WR+AW, and WS+NW treatments.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8346148

  15. Kids Count in Indiana: 1996 Data Book.

    ERIC Educational Resources Information Center

    Erickson, Judith B.

    This Kids Count report is the third in a series examining statewide trends in the well-being of Indiana's children. The report combines statistics of special concern in Indiana with 10 national Kids Count well-being indicators: (1) percent low birthweight; (2) infant mortality rate; (3) child death rate; (4) birth rate to unmarried teens ages 15…

  16. Mice can count and optimize count-based decisions.

    PubMed

    Çavdaroğlu, Bilgehan; Balcı, Fuat

    2016-06-01

    Previous studies showed that rats and pigeons can count their responses, and the resultant count-based judgments exhibit the scalar property (also known as Weber's Law), a psychophysical property that also characterizes interval-timing behavior. Animals were found to take a nearly normative account of these well-established endogenous uncertainty characteristics in their time-based decision-making. On the other hand, no study has yet tested the implications of scalar property of numerosity representations for reward-rate maximization in count-based decision-making. The current study tested mice on a task that required them to press one lever for a minimum number of times before pressing the second lever to collect the armed reward (fixed consecutive number schedule, FCN). Fewer than necessary number of responses reset the response count without reinforcement, whereas emitting responses at least for the minimum number of times reset the response counter with reinforcement. Each mouse was tested with three different FCN schedules (FCN10, FCN20, FCN40). The number of responses emitted on the first lever before pressing the second lever constituted the main unit of analysis. Our findings for the first time showed that mice count their responses with scalar property. We then defined the reward-rate maximizing numerical decision strategies in this task based on the subject-based estimates of the endogenous counting uncertainty. Our results showed that mice learn to maximize the reward-rate by incorporating the uncertainty in their numerosity judgments into their count-based decisions. Our findings extend the scope of optimal temporal risk-assessment to the domain of count-based decision-making. PMID:26463617

  17. High performance interconnection between high data rate networks

    NASA Technical Reports Server (NTRS)

    Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

    1992-01-01

    The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

  18. 48 CFR 1609.7101-2 - Community-rated carrier performance factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Community-rated carrier... CONTRACTOR QUALIFICATIONS Performance Evaluation 1609.7101-2 Community-rated carrier performance factors. OPM... specified by the contracting officer when a community-rated carrier does not provide the...

  19. 48 CFR 1609.7101-2 - Community-rated carrier performance factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Community-rated carrier... CONTRACTOR QUALIFICATIONS Performance Evaluation 1609.7101-2 Community-rated carrier performance factors. OPM... specified by the contracting officer when a community-rated carrier does not provide the...

  20. 48 CFR 1609.7101-2 - Community-rated carrier performance factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Community-rated carrier... CONTRACTOR QUALIFICATIONS Performance Evaluation 1609.7101-2 Community-rated carrier performance factors. OPM... specified by the contracting officer when a community-rated carrier does not provide the...

  1. 48 CFR 1609.7101-2 - Community-rated carrier performance factors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Community-rated carrier... CONTRACTOR QUALIFICATIONS Performance Evaluation 1609.7101-2 Community-rated carrier performance factors. OPM... specified by the contracting officer when a community-rated carrier does not provide the...

  2. 48 CFR 1609.7101-2 - Community-rated carrier performance factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Community-rated carrier... CONTRACTOR QUALIFICATIONS Performance Evaluation 1609.7101-2 Community-rated carrier performance factors. OPM... specified by the contracting officer when a community-rated carrier does not provide the...

  3. Effects of Excerpt Tempo and Duration on Musicians' Ratings of High-Level Piano Performances

    ERIC Educational Resources Information Center

    Wapnick, Joel; Ryan, Charlene; Campbell, Louise; Deek, Patricia; Lemire, Renata; Darrow, Alice-Ann

    2005-01-01

    The purpose of this study was to determine how judgments of solo performances recorded at an international piano competition might be affected by excerpt duration (20 versus 60 seconds) and tempo (slow versus fast). Musicians rated performances on six test items. Results indicated that piano majors rated slow excerpts higher than they rated fast…

  4. Ratings of Violin and Viola Vibrato Performance in Audio-Only and Audiovisual Presentations.

    ERIC Educational Resources Information Center

    Gillespie, Robert

    1997-01-01

    Compares the ratings assigned to audio and videotaped vibrato performances of inexperienced and experienced violinists and violists. Rated the performances on five vibrato factors: width, speed, evenness, pitch stability, and overall sound. Although the experienced players were consistently rated higher, the results suggested that visual cues may…

  5. Comparison of On-Orbit Performance of Rate Sensing Gyroscopes

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph; Hashmall, Joseph; Airapetian, Vladimir

    2000-01-01

    This work presents results from the study of a large volume of spacecraft flight data pertaining to gyroscope performance. We have examined long and short term trends of gyroscope biase of first, an exact solution for the time-dependence of the attitude part of the state error covariance, averaged over the three spacecraft axes, is given. This solution is more complete than the usual cubic polynomial for the variance in that it includes coupling among the three gyroscope axes and includes an important term arising from the initial correlations. Second, several continuous 24-hour spans of gyroscope data are examined to verify the short-term statistical model. This analysis demonstrates that in-flight data can be used to determine the strength of the white noise driving the random walk of the gyroscope bias. This may be useful for postlaunch improvement to the noise model and for diagnosing the health of the gyroscope. Third, the long-term trends in gyroscope biases show a nearly linear systematic variation over time scales of years. This has been found on three different missions. While the random walk model is adequate as a basis for onboard Kalman filters or for state estimation using relatively short time spans, these trends indicate that some applications could benefit by accounting for the secular changes in the biases. One example is a new gyroscope calibration method that is under development that allows for multi-epoch bias solutions.

  6. Capacity approaching codes for photon counting receivers

    NASA Astrophysics Data System (ADS)

    Mondin, Marina; Daneshgaran, Fred; Bari, Inam; Delgado, Maria Teresa

    2012-10-01

    [1] a low-complexity photon-counting receiver has been presented, which may be employed for weak-energy optical communications and which is typically modeled through its equivalent Binary Symmetric Channel (BSC) model. In this paper we consider the scheme described in [1], we model it as a time varying Binary Input-Multiple Output (BIMO) channel and analyze its performance in presence of soft-metric based capacity approaching iteratively decoded error correcting codes, and in particular using soft-metric based Low Density Parity Check (LDPC) codes. To take full advantage of such detector, soft information is generated in the form of Log-Likelihood Ratios (LLRs), achieving reduction in Bit Error Rate (BER) and Frame Error Rate (FER) with respect to classical BSC and Additive White Gaussian Noise (AWGN) channel models. Furthermore, we explore the limits of the achievable performance gains when using photon counting detectors as compared to the case when such detectors are not available. To this end, we find the classical capacity of the considered BIMO channel, clearly showing the potential gains that photon counting detectors can provide in the context of a realistic cost-effective scheme from an implementation point of view. Furthermore, we show that from a channel modeling point of view, we can observe that the BIMO channel can be approximated with an AWGN channel for high values of mean photon count Nc, while the AWGN model offers an unreliable result with a low mean photon number Nc, (i.e. with low raw BER). This effect is more evident with lower coding rates.

  7. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras.

    PubMed

    Kristoffersen, Miklas S; Dueholm, Jacob V; Gade, Rikke; Moeslund, Thomas B

    2016-01-01

    The number of pedestrians walking the streets or gathered in public spaces is a valuable piece of information for shop owners, city governments, event organizers and many others. However, automatic counting that takes place day and night is challenging due to changing lighting conditions and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows success rates of 95.4% and 99.1% for the two sequences. PMID:26742047

  8. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras

    PubMed Central

    Kristoffersen, Miklas S.; Dueholm, Jacob V.; Gade, Rikke; Moeslund, Thomas B.

    2016-01-01

    The number of pedestrians walking the streets or gathered in public spaces is a valuable piece of information for shop owners, city governments, event organizers and many others. However, automatic counting that takes place day and night is challenging due to changing lighting conditions and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows success rates of 95.4% and 99.1% for the two sequences. PMID:26742047

  9. 12 CFR 563e.21 - Performance tests, standards, and ratings, in general.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Performance tests, standards, and ratings, in general. 563e.21 Section 563e.21 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY COMMUNITY REINVESTMENT Standards for Assessing Performance § 563e.21 Performance tests, standards, and ratings, in general. (a)...

  10. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... administrative fee reserve for other housing purposes (see 24 CFR 982.155(b)). (f) Upgrading poor performance... troubled performance rating. 985.107 Section 985.107 Housing and Urban Development Regulations Relating to... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1)...

  11. A Pixel Readout Chip in 40 nm CMOS Process for High Count Rate Imaging Systems with Minimization of Charge Sharing Effects

    SciTech Connect

    Maj, Piotr; Grybos, P.; Szczgiel, R.; Kmon, P.; Drozd, A.; Deptuch, G.

    2013-11-07

    We present a prototype chip in 40 nm CMOS technology for readout of hybrid pixel detector. The prototype chip has a matrix of 18x24 pixels with a pixel pitch of 100 m. It can operate both in single photon counting (SPC) mode and in C8P1 mode. In SPC the measured ENC is 84 e rms (for the peaking time of 48 ns), while the effective offset spread is below 2 mV rms. In the C8P1 mode the chip reconstructs full charge deposited in the detector, even in the case of charge sharing, and it identifies a pixel with the largest charge deposition. The chip architecture and preliminary measurements are reported.

  12. An examination of raters' and ratees' preferences in process and feedback in performance appraisal.

    PubMed

    Manshor, A T; Kamalanabhan, T J

    2000-02-01

    This paper examined the raters' and the ratees' preferences in Malaysia regarding the performance appraisal process and feedback. A total of 52 managers (raters) and 122 subordinates (ratees) participated. Analysis by t test and correlation showed significant differences between raters and the ratees on most factors. Ratees preferred to have more frequent appraisals than once a year and preferred to have more frequent feedback from the managers about their performance. Ratees' preference for the purpose of information on performance was towards salary increase, promotion, training, and career development whereas the raters gave more importance to training and career development. PMID:10778271

  13. Recommendations for the performance rating of flat plate terrestrial photovoltaic solar panels

    NASA Technical Reports Server (NTRS)

    Treble, F. C.

    1976-01-01

    A review of recommendations for standardizing the performance rating of flat plate terrestrial solar panels is given to develop an international standard code of practice for performance rating. Required data to characterize the performance of a solar panel are listed. Other items discussed are: (1) basic measurement procedures; (2) performance measurement in natural sunlight and simulated sunlight; (3) standard solar cells; (4) the normal incidence method; (5) global method and (6) definition of peak power.

  14. Enabling photon counting detectors with dynamic attenuators

    NASA Astrophysics Data System (ADS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-03-01

    Photon-counting x-ray detectors (PCXDs) are being investigated as a replacement for conventional x-ray detectors because they promise several advantages, including better dose efficiency, higher resolution and spectral imaging. However, many of these advantages disappear when the x-ray flux incident on the detector is too high. We recently proposed a dynamic, piecewise-linear attenuator (or beam shaping filter) that can control the flux incident on the detector. This can restrict the operating range of the PCXD to keep the incident count rate below a given limit. We simulated a system with the piecewise-linear attenuator and a PCXD using raw data generated from forward projected DICOM files. We investigated the classic paralyzable and nonparalyzable PCXD as well as a weighted average of the two, with the weights chosen to mimic an existing PCXD (Taguchi et al, Med Phys 2011). The dynamic attenuator has small synergistic benefits with the nonparalyzable detector and large synergistic benefits with the paralyzable detector. Real PCXDs operate somewhere between these models, and the weighted average model still shows large benefits from the dynamic attenuator. We conclude that dynamic attenuators can reduce the count rate performance necessary for adopting PCXDs.

  15. Compensatory and Noncompensatory Information Integration and Halo Error in Performance Rating Judgments.

    ERIC Educational Resources Information Center

    Kishor, Nand

    1992-01-01

    The relationship between compensatory and noncompensatory information integration and the intensity of the halo effect in performance rating was studied. Seventy University of British Columbia (Canada) students rated 27 teacher profiles. That the way performance information is mentally integrated affects the intensity of halo error was supported.…

  16. What Are Error Rates for Classifying Teacher and School Performance Using Value-Added Models?

    ERIC Educational Resources Information Center

    Schochet, Peter Z.; Chiang, Hanley S.

    2013-01-01

    This article addresses likely error rates for measuring teacher and school performance in the upper elementary grades using value-added models applied to student test score gain data. Using a realistic performance measurement system scheme based on hypothesis testing, the authors develop error rate formulas based on ordinary least squares and…

  17. The Effect of Selected Nonmusical Factors on Adjudicators' Ratings of High School Solo Vocal Performances

    ERIC Educational Resources Information Center

    Howard, Sandra A.

    2012-01-01

    The purpose of this study was to examine the effect of differentiated performance attire and stage deportment on adjudicators' ratings of high school solo vocal performances. High school choral students (n = 153) and undergraduate (n = 97) and graduate music majors (n = 32) served as adjudicators (N = 282). Adjudicators rated recorded solo vocal…

  18. Relationships among Conducting Quality, Ensemble Performance Quality, and State Festival Ratings

    ERIC Educational Resources Information Center

    Price, Harry E.

    2006-01-01

    This study was the third in a series examining the relationships among conductors, ensembles' performances, and festival ratings. Participants (N = 51) were asked to score the quality of video-only conducting and parallel audio-only excerpts of performances at a state-level concert festival of nine bands, three each that had received ratings of…

  19. A Comparison of Three Modes of Student Ratings of Teacher Performance

    ERIC Educational Resources Information Center

    Rice, Larry S.; Van Duzer, Eric V.

    2005-01-01

    One of the primary means of evaluating teaching effectiveness in higher education is through the use of end-of-term student ratings of teacher performance. A number of universities have begun experimenting with replacing the traditional paper and pencil rating forms with on-line forms. Because student ratings often play a key role in personnel…

  20. Preliminary results from the evaluation of Cockpit Resource Management training - Performance ratings of flightcrews

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.; Wilhelm, John A.; Gregorich, Steven E.; Chidester, Thomas R.

    1990-01-01

    The first data from the NASA/University of Texas Crew Performance project on the behavior of flightcrews with and without formal training in Cockpit Resource Management (CRM) is reported. Expert observers made detailed ratings of 15 components of crew behavior in both line operations and in full mission simulations. The results indicate that such training in crew coordination concepts increases the percentage of crews rated as above average in performance and decreases the percentage rated as below average. The data also show high and unexpected degrees of variations in rated performance among crews flying different aircraft within the same organization. It was also found that the specific behaviors that triggered observer ratings of above or below average performance differed markedly between organizations. Characteristics of experts' ratings and future research needs are also discussed.

  1. Loss-Free Counting with Digital Signal Processors

    SciTech Connect

    Markku Koskelo; Dave Hall; Martin Moslinger

    2000-11-12

    Loss-free-counting (LFC) techniques have frequently been used with traditional analog pulse processing systems to compensate for the time or pulses lost when a spectroscopy system is unavailable (busy) for processing an accepted pulse. With the availability of second-generation digital signal processing (DSP) electronics that offer a significantly improved performance for both high and low count rate applications, the LFC technique has been revisited. Specific attention was given to the high and ultra-high count rate behavior, using high-purity germanium (HPGe) detectors with both transistor reset preamplifiers (TRP) and conventional RC preamplifiers. The experiments conducted for this work show that the known LFC techniques further benefit when combined with modern DSP pulse shaping.

  2. The five-factor model of personality and managerial performance: validity gains through the use of 360 degree performance ratings.

    PubMed

    Oh, In-Sue; Berry, Christopher M

    2009-11-01

    This study investigated the usefulness of the five-factor model (FFM) of personality in predicting two aspects of managerial performance (task vs. contextual) assessed by utilizing the 360 degree performance rating system. The authors speculated that one reason for the low validity of the FFM might be the failure of single-source (e.g., supervisor) ratings to comprehensively capture the construct of managerial performance. The operational validity of personality was found to increase substantially (50%-74%) across all of the FFM personality traits when both peer and subordinate ratings were added to supervisor ratings according to the multitrait-multimethod approach. Furthermore, the authors responded to the recent calls to validate tests via a multivariate (e.g., multitrait-multimethod) approach by decomposing overall managerial performance into task and contextual performance criteria and by using multiple rating perspectives (sources). Overall, this study contributes to the evidence that personality may be even more useful in predicting managerial performance if the performance criteria are less deficient. PMID:19916658

  3. The Rating of High-Performing Principals' Performance on Their Leadership Dimensions by Senior Administrators, Middle Managers and Classroom Teachers

    ERIC Educational Resources Information Center

    Hutton, Disraeli Montgomery

    2016-01-01

    The purpose of the study was to determine if there was a difference in the ratings among senior administrators/managers, middle managers and classroom teachers of the four dimensions of leadership performance related to high-performing principals in the Jamaican public school system. The study showed that there were differences in how senior…

  4. The Big Pumpkin Count.

    ERIC Educational Resources Information Center

    Coplestone-Loomis, Lenny

    1981-01-01

    Pumpkin seeds are counted after students convert pumpkins to jack-o-lanterns. Among the activities involved, pupils learn to count by 10s, make estimates, and to construct a visual representation of 1,000. (MP)

  5. Comparative diagnostic and prognostic performances of the hematoxylin-eosin and phospho-histone H3 mitotic count and Ki-67 index in adrenocortical carcinoma.

    PubMed

    Duregon, Eleonora; Molinaro, Luca; Volante, Marco; Ventura, Laura; Righi, Luisella; Bolla, Stefania; Terzolo, Massimo; Sapino, Anna; Papotti, Mauro G

    2014-09-01

    Mitotic count on hematoxylin and eosin slides is a fundamental morphological criterion in the diagnosis and grading of adrenocortical carcinoma in any scoring system employed. Moreover, it is the unique term strongly associated with patient's prognosis. Phospho-histone H3 is a mitosis-specific antibody, which was already proven to facilitate mitotic count in melanoma and other tumors. Therefore, a study was designed to assess the diagnostic and prognostic role of phospho-histone H3 in 52 adrenocortical carcinomas, comparing manual and computerized count to standard manual hematoxylin- and eosin-based method and Ki-67 index. Manual hematoxylin and eosin and phospho-histone H3 mitotic counts were highly correlated (r=0.9077, P<0.0001), better than computer-assisted phospho-histone H3 evaluations, and had an excellent inter-observer reproducibility at Bland-Altman analysis. Three of 15 cases having <5 mitotic figures per 50 high-power fields by standard count on hematoxylin and eosin gained the mitotic figure point of Weiss Score after a manual count on phospho-histone H3 slides. Traditional mitotic count confirmed to be a strong predictor of overall survival (P=0.0043), better than phospho-histone H3-based evaluation (P=0.051), but not as strong as the Ki-67 index (P<0.0001). The latter further segregated adrenocortical carcinomas into three prognostic groups, stratifying cases by low (<20%), intermediate (20-50%), and high (>50%) Ki-67 values. We conclude that (a) phospho-histone H3 staining is a useful diagnostic complementary tool to standard hematoxylin and eosin mitotic count, enabling optimal mitotic figure evaluation (including atypical mitotic figures) even in adrenocortical carcinomas with a low mitotic index and with a very high reproducibility; (b) Ki-67 proved to be the best prognostic indicator of overall survival, being superior to the mitotic index, irrespective of the method (standard on hematoxylin and eosin or phospho-histone H3-based) used to count

  6. 12 CFR 25.21 - Performance tests, standards, and ratings, in general.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Performance tests, standards, and ratings, in general. 25.21 Section 25.21 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY COMMUNITY REINVESTMENT ACT AND INTERSTATE DEPOSIT PRODUCTION REGULATIONS Regulations Standards for Assessing Performance § 25.21 Performance...

  7. 12 CFR 228.21 - Performance tests, standards, and ratings, in general.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 3 2011-01-01 2011-01-01 false Performance tests, standards, and ratings, in general. 228.21 Section 228.21 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM COMMUNITY REINVESTMENT (REGULATION BB) Standards for Assessing Performance § 228.21 Performance tests, standards,...

  8. Avian leucocyte counting using the hemocytometer

    USGS Publications Warehouse

    Dein, F.J.; Wilson, A.; Fischer, D.; Langenberg, P.

    1994-01-01

    Automated methods for counting leucocytes in avian blood are not available because of the presence of nucleated erythrocytes and thrombocytes. Therefore, total white blood cell counts are performed by hand using a hemocytometer. The Natt and Herrick and the Unopette methods are the most common stain and diluent preparations for this procedure. Replicate hemocytometer counts using these two methods were performed on blood from four birds of different species. Cells present in each square of the hemocytometer were counted. Counting cells in the corner, side, or center hemocytometer squares produced statistically equivalent results; counting four squares per chamber provided a result similar to that obtained by counting nine squares; and the Unopette method was more precise for hemocytometer counting than was the Natt and Herrick method. The Unopette method is easier to learn and perform but is an indirect process, utilizing the differential count from a stained smear. The Natt and Herrick method is a direct total count, but cell identification is more difficult.

  9. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.

    PubMed

    von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

    2013-08-01

    Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses. PMID:23380228

  10. How Many Cases of Spine Surgery Are Performed in Germany? Method of Counting the Number of Cases of Spine Surgery in Germany.

    PubMed

    Wieser, Lea-Marie; Sauermann, Sven; Weber, Friedrich

    2016-09-01

    Objective The number of cases of spinal DRGs (German Diagnosis-Related Groups) is calculated on the basis of the data released by the German DRG-Institute. The data thus obtained were subsequently compared with the previously publicly debated data of cases, which were based on the counting of OPS (German Procedure Classification) codes. Methods Specific and Nonspecific Spinal DRGs are identified according to the German Coding Guidelines and the OPS catalogs. Those are verified in a multistage process, including the formation of test cases, to ensure that those DRGs consistently contain spinal cases. The verified DRGs are filtered out of the G-DRG § 21 KHEntgG Browser, including the years from 2005 to 2012 to calculate the respective number of cases. For a better overview, the DRGs are divided into groups according to Specific and Nonspecific Spinal DRGs. Both groups are summarized under the title Surgical Spine DRGs to be able to compare the results with the data already published. Two datasets are used for comparison: one from a publication in the German Ärzteblatt, which is based on the data collected by the German insurance company AOK, and the other from data published by the German Federal Office of Statistics. Results As a result, the number of cases which is presented here shows a significant variance compared with the figures that have been published. The Specific Spinal DRGs show a growth of 75% from 2005 to 2011. The case numbers of the Nonspecific Spinal DRGs show an increased rate of 51% between 2005 and 2006. In addition, the Surgical Spine DRGs rose by 69% between 2005 and 2011. This contrasts with the German government-proposed increase of 125% in the area of spinal surgery over the same period. Conclusion To summarize, the significant gap between the case numbers presented here and the existing ones gives reason to question the benefit of using OPS codes to calculate the actual number of cases in the field of spinal surgery, and it

  11. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

    PubMed Central

    Arslan, Erşan; Aras, Dicle

    2016-01-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  12. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... high performer may receive national recognition by the Department and may be given competitive advantage under notices of fund availability. (b) Standard rating. PHAs with SEMAP scores of 60 to...

  13. Inventive Performance Improvement of Integrated Optical Rate Sensor Using TIPS/TRIZ

    NASA Technical Reports Server (NTRS)

    Blosiu, Julian O.; Youmans, Bruce R.; Kowalick, Jim

    1996-01-01

    The Theory of Inventive Problem Solving (TIPS or also known as TRIZ) is a new scientific approach to innovative improvements of products and processes. This methodology was applied to inventively improve performance of an Integrated Optic Rate Sensor (IORS).

  14. Morning employees are perceived as better employees: employees' start times influence supervisor performance ratings.

    PubMed

    Yam, Kai Chi; Fehr, Ryan; Barnes, Christopher M

    2014-11-01

    In this research, we draw from the stereotyping literature to suggest that supervisor ratings of job performance are affected by employees' start times-the time of day they first arrive at work. Even when accounting for total work hours, objective job performance, and employees' self-ratings of conscientiousness, we find that a later start time leads supervisors to perceive employees as less conscientious. These perceptions in turn cause supervisors to rate employees as lower performers. In addition, we show that supervisor chronotype acts as a boundary condition of the mediated model. Supervisors who prefer eveningness (i.e., owls) are less likely to hold negative stereotypes of employees with late start times than supervisors who prefer morningness (i.e., larks). Taken together, our results suggest that supervisor ratings of job performance are susceptible to stereotypic beliefs based on employees' start times. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24911178

  15. South Carolina Kids Count, 2000.

    ERIC Educational Resources Information Center

    Holmes, A. Baron

    This Kids Count report examines statewide trends in the well-being of South Carolina's children. The statistical portrait is based on 41 indicators in the areas of demographics, family, economic status, health, readiness and early school performance, scholastic achievement, and adolescent risk behaviors. The indicators are: (1) population; (2)…

  16. South Carolina Kids Count, 2001.

    ERIC Educational Resources Information Center

    Holmes, A. Baron

    This Kids Count report examines statewide trends in the well-being of South Carolina's children. The statistical portrait is based on 42 indicators in the areas of demographics, family, economic status, health, readiness and early school performance, scholastic achievement, and adolescent risk behaviors. The indicators are: (1) population; (2)…

  17. The Effects of Total Motile Sperm Count on Spontaneous Pregnancy Rate and Pregnancy After IUI Treatment in Couples with Male Factor and Unexplained Infertility

    PubMed Central

    Hajder, Mithad; Hajder, Elmira; Husic, Amela

    2016-01-01

    Introduction: Male infertility factor is defined if the total number of motile spermatozoa (TMSC) < 20 × 106/ejaculated, and unexplained infertility if spermiogram is normal with normal female factor. The aim: of this study was to determine the predictive value of TMSC for spontaneous pregnancy (ST) and pregnancy after treatment with intrauterine insemination (IUI) in couples with male factor and unexplained infertility. What is known already: According to the WHO qualification system abnormal spermiogram can be diagnosed as oligozoospermia (O), asthenozoospermia (A), teratozoospermia (T) or combination (O+A+T) and azoospermia (A). Although this classification indicates the accuracy of findings its relevance for prognosis in infertile couple and the choice of treatment is questionable. Materials and Methods: The study included 98 couples with male infertility factor (bad spermiogram) and couples with normospermia and normal female factor (unexplained infertility). Testing group is randomized at: group (A) with TMSC> 3,106 / ejaculate and a spontaneous pregnancy, group (B) with TMSCl <3 x 106 / ejaculate and pregnancy after IUI, plus couples who have not achieved SP with TMSC> 3 x 106 / ejaculate and couples who have not achieved pregnancy. Main results: From a total of 98 pairs of men’s and unexplained infertility, 42 of them (42.8%) achieved spontaneous pregnancy, while 56 (57.2%) pairs did not achieve spontaneous pregnancy. TMSC was significantly higher (42.4 ± 28.4 vs. 26.2 ± 24, p <0.05) in the group A compared to group B. Couples with TMSC 1-5 × 106 ejaculate had significantly lower (9.8% vs. 22.2%, p <0.0001) rate of spontaneous pregnancy in comparison to couples after IUI treatment. Couples with unexplained infertility had significantly higher (56.8% vs. 29.9%, p <0.01) spontaneous pregnancy rate compared to couples after IUI treatment. Infertile couples had significant pregnancy rate with TMSC 5-10 x 106 / ejaculate (OR = 1.45, 95% CI:1.26-1.78, <0

  18. Photon Counting Using Edge-Detection Algorithm

    NASA Technical Reports Server (NTRS)

    Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

    2010-01-01

    New applications such as high-datarate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with subnanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to overcount the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA). Systems have been developed and implemented to both characterize gigahertz bandwidth single-photon detectors, as well as process photon count signals at rates into gigaphotons per second in order to implement communications links at SCPPM (serial concatenated pulse position modulation) encoded data rates exceeding 100 megabits per second with efficiencies greater than two bits per detected photon. A hardware edge-detection algorithm and corresponding signal combining and deserialization hardware were developed to meet these requirements at sample rates up to 10 GHz. The photon discriminator deserializer hardware board accepts four inputs, which allows for the ability to take inputs from a quadphoton counting detector, to support requirements for optical tracking with a reduced number of hardware components. The four inputs are hardware leading-edge detected independently. After leading-edge detection, the resultant samples are ORed together prior to deserialization. The deserialization is performed to reduce the rate at which data is passed to a digital signal processor, perhaps residing within an FPGA. The hardware implements four separate analog inputs that are connected through RF connectors. Each analog input is fed to a high-speed 1

  19. Preschool Children's Spontaneous Focusing on Numerosity, Subitizing, and Counting Skills as Predictors of Their Mathematical Performance Seven Years Later at School

    ERIC Educational Resources Information Center

    Hannula-Sormunen, Minna M.; Lehtinen, Erno; Räsänen, Pekka

    2015-01-01

    This seven-year longitudinal study examined how children's spontaneous focusing on numerosity (SFON), subitizing based enumeration, and counting skills assessed at five or six years predict their school mathematics achievement at 12 years. The participants were 36 Finnish children without diagnosed neurological disorders. The results, based on…

  20. Guidance on the Use of Hand-Held Survey Meters for Radiological Triage: Time-Dependent Detector Count Rates Corresponding to 50, 250, and 500 mSv Effective Dose for Adult Males and Adult Females

    PubMed Central

    Bolch, Wesley E.; Hurtado, Jorge L.; Lee, Choonsik; Manger, Ryan; Hertel, Nolan; Dickerson, William

    2013-01-01

    In June of 2006, the Radiation Studies Branch of the Centers for Disease Control and Prevention held a workshop to explore rapid methods of facilitating radiological triage of large numbers of potentially contaminated individuals following detonation of a radiological dispersal device. Two options were discussed. The first was the use of traditional gamma-cameras in nuclear medicine departments operated as make-shift whole-body counters. Guidance on this approach is currently available from the CDC. This approach is feasible if a manageable number of individuals were involved, transportation to the relevant hospitals was quickly provided, and the medical staff at each facility had been previously trained in this non-traditional use of their radiopharmaceutical imaging devices. If, however, substantially large numbers of individuals (100s to 1000s) needed radiological screening, other options must be given to first responders, first receivers, and health physicists providing medical management. In this study, the second option of the workshop was investigated – the use of commercially available portable survey meters (either NaI or GM based) for assessing potential ranges of effective dose (<50, 50–250, 250–500, and >500 mSv). Two hybrid computational phantoms were used to model an adult male and an adult female subject internally contaminated with either 241Am, 60Cs, 137Cs, 131I, and 192Ir following an acute inhalation or ingestion intake. As a function of time following the exposure, the net count rates corresponding to committed effective doses of 50, 250, and 500 mSv were estimated via Monte Carlo radiation transport simulation for each of four different detectors types, positions, and screening distances. Measured count rates can be compared to these values and an assignment of one of four possible effective dose ranges could be made. The method implicitly assumes that all external contamination has been removed prior to screening, and that the

  1. Guidance on the Use of Hand-Held Survey Meters for radiological Triage: Time-Dependent Detector Count Rates Corresponding to 50, 250, and 500 mSv Effective Dose for Adult Males and Adult Females

    SciTech Connect

    Bolch, W.E.; Hurtado, J.L.; Lee, C.; Manger, Ryan P; Hertel, Nolan; Burgett, E.; Dickerson, W.

    2012-01-01

    In June 2006, the Radiation Studies Branch of the Centers for Disease Control and Prevention held a workshop to explore rapid methods of facilitating radiological triage of large numbers of potentially contaminated individuals following detonation of a radiological dispersal device. Two options were discussed. The first was the use of traditional gamma cameras in nuclear medicine departments operated as makeshift wholebody counters. Guidance on this approach is currently available from the CDC. This approach would be feasible if a manageable number of individuals were involved, transportation to the relevant hospitals was quickly provided, and the medical staff at each facility had been previously trained in this non-traditional use of their radiopharmaceutical imaging devices. If, however, substantially larger numbers of individuals (100 s to 1,000 s) needed radiological screening, other options must be given to first responders, first receivers, and health physicists providing medical management. In this study, the second option of the workshop was investigated by the use of commercially available portable survey meters (either NaI or GM based) for assessing potential ranges of effective dose (G50, 50Y250, 250Y500, and 9500 mSv). Two hybrid computational phantoms were used to model an adult male and an adult female subject internally contaminated with 241Am, 60Cs, 137Cs, 131I, or 192Ir following an acute inhalation or ingestion intake. As a function of time following the exposure, the net count rates corresponding to committed effective doses of 50, 250, and 500 mSv were estimated via Monte Carlo radiation transport simulation for each of four different detector types, positions, and screening distances. Measured net count rates can be compared to these values, and an assignment of one of four possible effective dose ranges could be made. The method implicitly assumes that all external contamination has been removed prior to screening and that the measurements be

  2. The Effects of Score Use on Musicians' Ratings of Choral Performances

    ERIC Educational Resources Information Center

    Napoles, Jessica

    2009-01-01

    The purpose of this study was to determine whether viewing a musical score while listening (as opposed to not viewing the score) would affect musicians' ratings of choral performance excerpts. University musicians (N = 240) listened to four excerpts of choral music (from Vivaldi's "Gloria") and rated them on a 10-point Likert-type scale for…

  3. A Study of Perkins 2P1 Graduation Performance Rates at Virginia Western Community College

    ERIC Educational Resources Information Center

    Archer, J. Andrew.

    2006-01-01

    "2P1" is the Carl Perkins label for an institution's graduation performance rate. Systems receiving Perkins funds, like Virginia's 23 community colleges, are expected to meet a federally approved 2P1 target rate. For the 3-year period 1999-2001 Virginia Western Community College (VWCC) was one of seven community colleges in the VCCS (Virginia…

  4. Effects of winter stocker growth rate and finishing system on: I. Animal performance and carcass characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Angus-crossbred steers (n = 216) were used in a three-year study to assess the effects of winter stocker growth rate and finishing system on finishing performance and carcass characteristics. During winter months (December to April) steers were randomly allotted to three stocker growth rates: low (...

  5. Rating Performance Assessments of Students with Disabilities: A Study of Reliability and Bias

    ERIC Educational Resources Information Center

    Mastergeorge, Ann M.; Martinez, Jose Felipe

    2010-01-01

    Inclusion of students with disabilities in district-wide and state assessments is mandated by federal regulations, and teachers sometimes play an important role in rating these students' work. In this study, trained teachers rated student proficiency in performance assessments in language arts and mathematics in third, fifth, and ninth grades. The…

  6. A Finite Rate Chemical Analysis of Nitric Oxide Flow Contamination Effects on Scramjet Performance

    NASA Technical Reports Server (NTRS)

    Cabell, Karen F.; Rock, Kenneth E.

    2003-01-01

    The level of nitric oxide contamination in the test gas of the Langley Research Center Arc-Heated Scramjet Test Facility and the effect of the contamination on scramjet test engine performance were investigated analytically. A finite rate chemical analysis was performed to determine the levels of nitric oxide produced in the facility at conditions corresponding to Mach 6 to 8 flight simulations. Results indicate that nitric oxide levels range from one to three mole percent, corroborating previously obtained measurements. A three-stream combustor code with finite rate chemistry was used to investigate the effects of nitric oxide on scramjet performance. Results indicate that nitric oxide in the test gas causes a small increase in heat release and thrust performance for the test conditions investigated. However, a rate constant uncertainty analysis suggests that the effect of nitric oxide ranges from no net effect, to an increase of about 10 percent in thrust performance.

  7. Ovarian Response and Cumulative Live Birth Rate of Women Undergoing In-Vitro Fertilisation Who Had Discordant Anti-Mullerian Hormone and Antral Follicle Count Measurements: A Retrospective Study

    PubMed Central

    Li, Hang Wun Raymond; Lee, Vivian Chi Yan; Lau, Estella Yee Lan; Yeung, William Shu Biu; Ho, Pak Chung; Ng, Ernest Hung Yu

    2014-01-01

    Objective To evaluate ovarian response and cumulative live birth rate of women undergoing in-vitro fertilization (IVF) treatment who had discordant baseline serum anti-Mullerian hormone (AMH) level and antral follicle count (AFC). Methods This is a retrospective cohort study on 1,046 women undergoing the first IVF cycle in Queen Mary Hospital, Hong Kong. Subjects receiving standard IVF treatment with the GnRH agonist long protocol were classified according to their quartiles of baseline AMH and AFC measurements after GnRH agonist down-regulation and before commencing ovarian stimulation. The number of retrieved oocytes, ovarian sensitivity index (OSI) and cumulative live-birth rate for each classification category were compared. Results Among our studied subjects, 32.2% were discordant in their AMH and AFC quartiles. Among them, those having higher AMH within the same AFC quartile had higher number of retrieved oocytes and cumulative live-birth rate. Subjects discordant in AMH and AFC had intermediate OSI which differed significantly compared to those concordant in AMH and AFC on either end. OSI of those discordant in AMH and AFC did not differ significantly whether either AMH or AFC quartile was higher than the other. Conclusions When AMH and AFC are discordant, the ovarian responsiveness is intermediate between that when both are concordant on either end. Women having higher AMH within the same AFC quartile had higher number of retrieved oocytes and cumulative live-birth rate. PMID:25313856

  8. Photon Counting - One More Time

    NASA Astrophysics Data System (ADS)

    Stanton, Richard H.

    2012-05-01

    Photon counting has been around for more than 60 years, and has been available to amateurs for most of that time. In most cases single photons are detected using photomultiplier tubes, "old technology" that became available after the Second World War. But over the last couple of decades the perfection of CCD devices has given amateurs the ability to perform accurate photometry with modest telescopes. Is there any reason to still count photons? This paper discusses some of the strengths of current photon counting technology, particularly relating to the search for fast optical transients. Technology advances in counters and photomultiplier modules are briefly mentioned. Illustrative data are presented including FFT analysis of bright star photometry and a technique for finding optical pulses in a large file of noisy data. This latter technique is shown to enable the discovery of a possible optical flare on the polar variable AM Her.

  9. Hanford whole body counting manual

    SciTech Connect

    Palmer, H.E.; Rieksts, G.A.; Lynch, T.P.

    1990-06-01

    This document describes the Hanford Whole Body Counting Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy--Richland Operations Office (DOE-RL) and its Hanford contractors. Program services include providing in vivo measurements of internally deposited radioactivity in Hanford employees (or visitors). Specific chapters of this manual deal with the following subjects: program operational charter, authority, administration, and practices, including interpreting applicable DOE Orders, regulations, and guidance into criteria for in vivo measurement frequency, etc., for the plant-wide whole body counting services; state-of-the-art facilities and equipment used to provide the best in vivo measurement results possible for the approximately 11,000 measurements made annually; procedures for performing the various in vivo measurements at the Whole Body Counter (WBC) and related facilities including whole body counts; operation and maintenance of counting equipment, quality assurance provisions of the program, WBC data processing functions, statistical aspects of in vivo measurements, and whole body counting records and associated guidance documents. 16 refs., 48 figs., 22 tabs.

  10. Deep UV photon-counting detectors and applications

    NASA Astrophysics Data System (ADS)

    Shaw, Gary A.; Siegel, Andrew M.; Model, Joshua; Geboff, Adam; Soloviev, Stanislav; Vert, Alexey; Sandvik, Peter

    2009-05-01

    Photon counting detectors are used in many diverse applications and are well-suited to situations in which a weak signal is present in a relatively benign background. Examples of successful system applications of photon-counting detectors include ladar, bio-aerosol detection, communication, and low-light imaging. A variety of practical photon-counting detectors have been developed employing materials and technologies that cover the waveband from deep ultraviolet (UV) to the near-infrared. However, until recently, photoemissive detectors (photomultiplier tubes (PMTs) and their variants) were the only viable technology for photon-counting in the deep UV region of the spectrum. While PMTs exhibit extremely low dark count rates and large active area, they have other characteristics which make them unsuitable for certain applications. The characteristics and performance limitations of PMTs that prevent their use in some applications include bandwidth limitations, high bias voltages, sensitivity to magnetic fields, low quantum efficiency, large volume and high cost. Recently, DARPA has initiated a program called Deep UV Avalanche Photodiode (DUVAP) to develop semiconductor alternatives to PMTs for use in the deep UV. The higher quantum efficiency of Geiger-mode avalanche photodiode (GM-APD) detectors and the ability to fabricate arrays of individually-addressable detectors will open up new applications in the deep UV. In this paper, we discuss the system design trades that must be considered in order to successfully replace low-dark count, large-area PMTs with high-dark count, small-area GM-APD detectors. We also discuss applications that will be enabled by the successful development of deep UV GM-APD arrays, and we present preliminary performance data for recently fabricated silicon carbide GM-APD arrays.

  11. USING AN ADAPTER TO PERFORM THE CHALFANT-STYLE CONTAINMENT VESSEL PERIODIC MAINTENANCE LEAK RATE TEST

    SciTech Connect

    Loftin, B.; Abramczyk, G.; Trapp, D.

    2011-06-03

    Recently the Packaging Technology and Pressurized Systems (PT&PS) organization at the Savannah River National Laboratory was asked to develop an adapter for performing the leak-rate test of a Chalfant-style containment vessel. The PT&PS organization collaborated with designers at the Department of Energy's Pantex Plant to develop the adapter currently in use for performing the leak-rate testing on the containment vessels. This paper will give the history of leak-rate testing of the Chalfant-style containment vessels, discuss the design concept for the adapter, give an overview of the design, and will present results of the testing done using the adapter.

  12. A comparison of the performance of rating scales used in the diagnosis of postnatal depression.

    PubMed

    Thompson, W M; Harris, B; Lazarus, J; Richards, C

    1998-09-01

    The results of a study looking into the association between thyroid status and depression in the postpartum period were reanalysed to explore the psychometric properties of the rating scales employed. The performance of the Edinburgh Postnatal Depression Scale was found to be superior to that of the Hospital Anxiety and Depression Scale in identifying RDC-defined depression, and on a par with the observer-rated Hamilton Rating Scale for Depression, which it also matched for sensitivity to change in mood state over time. The anxiety subscale of the Hospital Anxiety and Depression Scale performed well, reflecting the fact that anxiety represents a prominent symptom in postnatal depression. PMID:9761410

  13. Impact of Verbal Scale Labels on the Elevation and Spread of Performance Ratings

    ERIC Educational Resources Information Center

    Kuhlemeier, Hans; Hemker, Bas; van den Bergh, Huub

    2013-01-01

    In recent years many countries have introduced authentic performance-based assessments in their national exam systems. Teachers' ratings of their own candidates' performances may suffer from errors of leniency and range restriction. The goal of this study was to examine the impact of manipulating the descriptiveness, balancedness, and polarity of…

  14. Language Arts Performance Assignments: Generalizability Studies of Local and Central Ratings

    ERIC Educational Resources Information Center

    Martinez, Jose Felipe; Goldschmidt, Pete; Niemi, David; Baker, Eva L.; Sylvester, Roxanne M.

    2007-01-01

    We conducted generalizability studies to examine the extent to which ratings of language arts performance assignments, administered in a large, diverse, urban district to students in second through ninth grades, result in reliable and precise estimates of true student performance. The results highlight three important points when considering the…

  15. Effects of Selected Variables on Musicians' Ratings of High-Level Piano Performances

    ERIC Educational Resources Information Center

    Wapnick, Joel; Ryan, Charlene; Lacaille, Nathalie; Darrow, Alice-Ann

    2004-01-01

    The purpose of this study was to ascertain whether judgments of solo performances recorded at a well-known international piano competition would be affected by musical characteristics such as style (classic period versus early 20th-century Russian) and tempo (slow versus fast). Evaluators rated performances on six test items: tone quality, note…

  16. Academic Performance and Pass Rates: Comparison of Three First-Year Life Science Courses

    ERIC Educational Resources Information Center

    Downs, C. T.

    2009-01-01

    First year students' academic performance in three Life Science courses (Botany, Zoology and Bioscience) was compared. Pass rates, as well as the means and distributions of final marks were analysed. Of the three components (coursework, practical and theory examinations) contributing to the final mark of each course, students performed best in the…

  17. Participation rate or informed choice? Rethinking the European key performance indicators for mammography screening.

    PubMed

    Strech, Daniel

    2014-03-01

    Despite the intensive controversies about the likelihood of benefits and harms of mammography screening almost all experts conclude that the choice to screen or not to screen needs to be made by the individual patient who is adequately informed. However, the "European guideline for quality assurance in breast cancer screening and diagnosis" specifies a participation rate of 70% as the key performance indicator for mammography screening. This paper argues that neither the existing evidence on benefits and harms, nor survey research with women, nor compliance rates in clinical trials, nor cost-effectiveness ratios justify participation rates as a reasonable performance indicator for preference-sensitive condition such as mammography screening. In contrast, an informed choice rate would be more reasonable. Further research needs to address the practical challenges in assessing informed choice rates. PMID:24332817

  18. An alternative calibration method for counting P-32 reactor monitors

    SciTech Connect

    Quirk, T.J.; Vehar, D.W.

    2011-07-01

    Radioactivation of sulfur is a common technique used to measure fast neutron fluences in test and research reactors. Elemental sulfur can be pressed into pellets and used as monitors. The {sup 32}S(n, p) {sup 32}P reaction has a practical threshold of about 3 MeV and its cross section and associated uncertainties are well characterized [1]. The product {sup 32P} emits a beta particle with a maximum energy of 1710 keV [2]. This energetic beta particle allows pellets to be counted intact. ASTM Standard Test Method for Measuring Reaction Rates and Fast-Neutron Fluences by Radioactivation of Sulfur-32 (E265) [3] details a method of calibration for counting systems and subsequent analysis of results. This method requires irradiation of sulfur monitors in a fast-neutron field whose spectrum and intensity are well known. The resultant decay-corrected count rate is then correlated to the known fast neutron fluence. The Radiation Metrology Laboratory (RML) at Sandia has traditionally performed calibration irradiations of sulfur pellets using the {sup 252}Cf spontaneous fission neutron source at the National Inst. of Standards and Technology (NIST) [4] as a transfer standard. However, decay has reduced the intensity of NIST's source; thus lowering the practical upper limits of available fluence. As of May 2010, neutron emission rates have decayed to approximately 3 e8 n/s. In practice, this degradation of capabilities precludes calibrations at the highest fluence levels produced at test reactors and limits the useful range of count rates that can be measured. Furthermore, the reduced availability of replacement {sup 252}Cf threatens the long-term viability of the NIST {sup 252}Cf facility for sulfur pellet calibrations. In lieu of correlating count rate to neutron fluence in a reference field the total quantity of {sup 32}P produced in a pellet can be determined by absolute counting methods. This offers an attractive alternative to extended {sup 252}Cf exposures because it

  19. Performance of a Micro-Strip Gas Chamber for event wise, high rate thermal neutron detection with accurate 2D position determination

    NASA Astrophysics Data System (ADS)

    Mindur, B.; Alimov, S.; Fiutowski, T.; Schulz, C.; Wilpert, T.

    2014-12-01

    A two-dimensional (2D) position sensitive detector for neutron scattering applications based on low-pressure gas amplification and micro-strip technology was built and tested with an innovative readout electronics and data acquisition system. This detector contains a thin solid neutron converter and was developed for time- and thus wavelength-resolved neutron detection in single-event counting mode, which improves the image contrast in comparison with integrating detectors. The prototype detector of a Micro-Strip Gas Chamber (MSGC) was built with a solid natGd/CsI thermal neutron converter for spatial resolutions of about 100 μm and counting rates up to 107 neutrons/s. For attaining very high spatial resolutions and counting rates via micro-strip readout with centre-of-gravity evaluation of the signal amplitude distributions, a fast, channel-wise, self-triggering ASIC was developed. The front-end chips (MSGCROCs), which are very first signal processing components, are read out into powerful ADC-FPGA boards for on-line data processing and thereafter via Gigabit Ethernet link into the data receiving PC. The workstation PC is controlled by a modular, high performance dedicated software suite. Such a fast and accurate system is crucial for efficient radiography/tomography, diffraction or imaging applications based on high flux thermal neutron beam. In this paper a brief description of the detector concept with its operation principles, readout electronics requirements and design together with the signals processing stages performed in hardware and software are presented. In more detail the neutron test beam conditions and measurement results are reported. The focus of this paper is on the system integration, two dimensional spatial resolution, the time resolution of the readout system and the imaging capabilities of the overall setup. The detection efficiency of the detector prototype is estimated as well.

  20. The association of culling and death rate within 30 days after calving with productivity or reproductive performance in dairy herds in Fukuoka, Southern Japan

    PubMed Central

    GOTO, Akira; NAKADA, Ken; KATAMOTO, Hiromu

    2015-01-01

    The incidence of peripartum disorders in dairy herds negatively influences productivity and reproductive performance. Concrete data from local areas are helpful for explaining the importance of peripartum management to dairy farmers. This study was conducted to clarify the association of culling and death rate within 30 days after calving with productivity or reproductive performance in 179 dairy herds in Fukuoka, Southern Japan. A database was compiled from the records of the Livestock Improvement Association of Japan, the Dairy Cooperative Association and the Federation of Agricultural Mutual Relief Association. In this study, we created a comprehensive database of dairy farm production data for epidemiological analysis and used a general linear mixed model to analyze the association of culling and death rate within 30 days after calving with milk production or reproductive performance. The database can be used to describe, analyze and predict the risk of production. A cross-sectional analysis with contrasts was applied to investigate the association of cows served by AI/all cows, pregnant cows/cows served by AI, days open, milk yield and somatic cell counts with culling and death rate within 30 days after calving. The days open value significantly increased with increasing rate of culling and death within 30 days after calving (P for trend <0.001). No significant differences were found for the other comparisons. Our data suggest that proper feeding and management in the dry period may lead to improved postpartum reproductive performance in this dairy cow cohort. PMID:26666177

  1. The association of culling and death rate within 30 days after calving with productivity or reproductive performance in dairy herds in Fukuoka, Southern Japan.

    PubMed

    Goto, Akira; Nakada, Ken; Katamoto, Hiromu

    2016-05-01

    The incidence of peripartum disorders in dairy herds negatively influences productivity and reproductive performance. Concrete data from local areas are helpful for explaining the importance of peripartum management to dairy farmers. This study was conducted to clarify the association of culling and death rate within 30 days after calving with productivity or reproductive performance in 179 dairy herds in Fukuoka, Southern Japan. A database was compiled from the records of the Livestock Improvement Association of Japan, the Dairy Cooperative Association and the Federation of Agricultural Mutual Relief Association. In this study, we created a comprehensive database of dairy farm production data for epidemiological analysis and used a general linear mixed model to analyze the association of culling and death rate within 30 days after calving with milk production or reproductive performance. The database can be used to describe, analyze and predict the risk of production. A cross-sectional analysis with contrasts was applied to investigate the association of cows served by AI/all cows, pregnant cows/cows served by AI, days open, milk yield and somatic cell counts with culling and death rate within 30 days after calving. The days open value significantly increased with increasing rate of culling and death within 30 days after calving (P for trend <0.001). No significant differences were found for the other comparisons. Our data suggest that proper feeding and management in the dry period may lead to improved postpartum reproductive performance in this dairy cow cohort. PMID:26666177

  2. Identification of CSF fistulas by radionuclide counting

    SciTech Connect

    Yamamoto, Y.; Kunishio, K.; Sunami, N.; Yamamoto, Y.; Satoh, T.; Suga, M.; Asari, S. )

    1990-07-01

    A radionuclide counting method, performed with the patient prone and the neck flexed, was used successfully to diagnose CSF rhinorrhea in two patients. A normal radionuclide ratio (radionuclide counts in pledget/radionuclide counts in 1-ml blood sample) was obtained in 11 normal control subjects. Significance was determined to be a ratio greater than 0.37. Use of radionuclide counting method of determining CSF rhinorrhea is recommended when other methods have failed to locate a site of leakage or when posttraumatic meningitis suggests subclinical CSF rhinorrhea.

  3. Internal Homogeneity, Descriptiveness, and Halo: Resurrecting Some Answers and Questions About the Structure of Job Performance Rating Categories.

    ERIC Educational Resources Information Center

    Cooper, William H.

    1983-01-01

    Assessed the effects of two rating category attributes on halo in job performance ratings. Results suggested reducing halo by using rating categories that do not force raters to rely on their overall evaluation of the ratee, or use the same salient observations for rating job performance on multiple categories. (JAC)

  4. New stimulation pattern design to improve P300-based matrix speller performance at high flash rate

    NASA Astrophysics Data System (ADS)

    Polprasert, Chantri; Kukieattikool, Pratana; Demeechai, Tanee; Ritcey, James A.; Siwamogsatham, Siwaruk

    2013-06-01

    Objective. We propose a new stimulation pattern design for the P300-based matrix speller aimed at increasing the minimum target-to-target interval (TTI). Approach. Inspired by the simplicity and strong performance of the conventional row-column (RC) stimulation, the proposed stimulation is obtained by modifying the RC stimulation through alternating row and column flashes which are selected based on the proposed design rules. The second flash of the double-flash components is then delayed for a number of flashing instants to increase the minimum TTI. The trade-off inherited in this approach is the reduced randomness within the stimulation pattern. Main results. We test the proposed stimulation pattern and compare its performance in terms of selection accuracy, raw and practical bit rates with the conventional RC flashing paradigm over several flash rates. By increasing the minimum TTI within the stimulation sequence, the proposed stimulation has more event-related potentials that can be identified compared to that of the conventional RC stimulations, as the flash rate increases. This leads to significant performance improvement in terms of the letter selection accuracy, the raw and practical bit rates over the conventional RC stimulation. Significance. These studies demonstrate that significant performance improvement over the RC stimulation is obtained without additional testing or training samples to compensate for low P300 amplitude at high flash rate. We show that our proposed stimulation is more robust to reduced signal strength due to the increased flash rate than the RC stimulation.

  5. A priori precision estimation for neutron triples counting

    SciTech Connect

    Croft, S.; Swinhoe, M. T.; Henzl, V.

    2011-07-01

    The nondestructive assay of Plutonium bearing items for criticality, safety, security, safeguards, inventory balance, process control, waste management and compliance is often undertaken using correlated neutron counting. In particular Multiplicity Shift Register analysis allows one to extract autocorrelation parameters from the pulse train which can, within the framework of a simple interpretational model, be related to the effective {sup 240}Pu spontaneous fission mass present. The effective {sup 240}Pu mass is a weighted sum of the {sup 238}Pu, {sup 240}Pu and {sup 242}Pu masses so if the relative isotopic composition of the Pu can be established from the measured {sup 240}Pu effective mass one can estimate the total Pu mass and also the masses of the individual isotopes, example the fissile species {sup 239}Pu and {sup 241}Pu. In multiplicity counting three counting rates are obtained. These are the Singles, Doubles and Triples rates. The Singles rate is just the gross, totals or trigger rate. The Doubles and Triples rates are calculated from factorial moments of the observed signal triggered neutron multiplicity distributions following spontaneous fission in the item and can be thought of as the rate of observed coincident pairs and coincident triplets on the pulse train. Coincident events come about because the spontaneous fission and induced fission chains taking place in the item result in bursts of neutrons. These remain time correlated during the detection process and so retain information, through the burst size distribution, about the Pu content. In designing and assessing the performance of a detector system to meet a given goal it is necessary to make a priori estimates of the counting precision for all three kinds of rates. This is non-trivial because the counting does not obey the familiar rules of a Poissonian counting experiment because the pulse train has time correlated events on it and the train is sampled by event triggered gates that may

  6. Systematic effects in neutron coincidence and multiplicity counting

    SciTech Connect

    Evans, Louise G; Favorite, Jeffrey A; Swinhoe, Martyn T

    2010-01-01

    Correlated neutron counting, including neutron coincidence and multiplicity counting, is an important tool in nuclear material accountancy verification. The accuracy of such measurements is of interest to the safeguards community because as the accuracy of NDA improves, the number of samples that are required to undergo destructive analysis (DA) decreases. The accuracy of a neutron mUltiplicity measurement can be affected by a number of variables. Monte Carlo neutron transport simulations with MCNPX have been performed to understand how the properties of the sample affect the count rate. These resultant count rates have been analyzed with the 'point model' in order to determine the effect on the deduced plutonium mass. The sample properties that have been investigated are density, sample position within the detector cavity, moisture content, isotopic composition, plutonium to total actinide ratio and heavy metal fraction. These parameters affect the Singles, Doubles and Triples count rates in different ways. In addition, different analysis methods use these measured quantities in different combinations, so that the final sensitivity of the {sup 240}Pu mass to each parameter also depends on the analysis method used. For example, the passive calibration curve method only used the Doubles rate to produce the {sup 240}Pu mass and so is not sensitive to changes in the Singles rate (to first order). The analysis methods considered here were passive calibration curve (non-multiplication corrected), known alpha (multiplication corrected) and multiplicity with known efficiency. The effects were studied on both a small mass MOX sample (1 g Pu) and a large MOX sample (6000 g Pu) both measured in high efficiency neutron multiplicity counters. In order to determine the final effect of each parameter it is necessary to know not only the sensitivity of the plutonium mass to that parameter, but also the range over which the parameter can realistically vary. Some estimates are

  7. Counting Sheep in Basque

    ERIC Educational Resources Information Center

    Araujo, Frank P.

    1975-01-01

    Demonstrates the interplay of a cognitive system, the Basque numerative system, and a behavioral one, counting sheep. The significant features of the Basque numerative system are analyzed; then it is shown how use of these features facilitates the counting of sheep on open ranges by Basque sheep farmers in California. (Author/RM)

  8. The Makah Counting Workbook.

    ERIC Educational Resources Information Center

    Flinn, Arlington A., Jr.

    The first edition of the counting workbook centers around the numbers from 1 to 100 and focuses on number and set concepts. The workbook introduces the Makah spelling of each number and reinforces the spelling with exercises such as matching words to numbers, writing the words, counting symbols, and circling the correct number. Spaced throughout…

  9. Complexities of Counting.

    ERIC Educational Resources Information Center

    Stake, Bernadine Evans

    This document focuses on one child's skip counting methods. The pupil, a second grade student at Steuben School, in Kankakee, Illinois, was interviewed as she made several attempts at counting twenty-five poker chips on a circular piece of paper. The interview was part of a larger study of "Children's Conceptions of Number and Numeral," funded by…

  10. Investigation of linear-mode photon-counting HgCdTe APDs for astronomical observations

    NASA Astrophysics Data System (ADS)

    Bryan, Marta L.; Chapman, George; Hall, Donald N. B.; Jack, Michael D.; Jacobson, Shane M.; Wehner, Justin

    2012-07-01

    The unique linear avalanche properties of HgCdTe preserve the Poisson statistics of the incoming photons, opening up new opportunities for GHz bandwidth LADAR and space communications applications. Raytheon has developed and previously reported (1) unique linear mode photon counting arrays based on combining advanced HgCdTe linear mode APDs with their high gain SB415B readout. Their use of HgCdTe APDs preserves the Poisson statistics of the incoming photons, enabling (noiseless) photon counting. This technology is of great potential interest to infrared astronomy but requires extension of noiseless linear HgCdTe avalanching down to much lower bandwidths (100 to 0.001 Hz) with corresponding reductions in dark count rate. We have hybridized the SB415B readout to SWIR HgCdTe APDs optimized for low dark count rate and have characterized their photon counting properties at bandwidths down to 1 KHz. As bandwidth is reduced, the performance becomes limited by the intrinsic properties of the SB415B readout, particularly readout glow, stability and 1/f noise. We report the results of these measurements and the status of hybrid arrays utilizing a newly developed readout which draws on Raytheon’s astronomical readout heritage, specifically the Virgo charge integrating source follower, as a path to much lower dark count rate photon counting operation.

  11. A complete database of international chess players and chess performance ratings for varied longitudinal studies.

    PubMed

    Howard, Robert W

    2006-11-01

    Chess is an oft-used study domain in psychology and artificial intelligence because it is well defined, its performance rating systems allow ea sy identification o f experts and their development, andchess playing is a complex intellectual task However, usable computerized chess data have been very limited. The present article has two aims. The first is to highlight the methodological value of chess data and how researchers can use them to address questions in quite different areas. The second is to present a computerized database of all international chess players and official performance ratings beginning from the inaugural 1970 international rating list. The database has millions of records and gives complete longitudinal official performance data for over 60,000 players from 1970 to the present. Like a time series of population censuses, these data can be used for many different research and teaching purposes. Three quite different studies, conducted by the author using the database, are described. PMID:17393842

  12. Effects of contingency contracting on study rate and test performance1

    PubMed Central

    Bristol, Marie M.; Sloane, Howard N.

    1974-01-01

    A contingency contracting program designed to increase study rate and subsequent test performance was implemented with a group of undergraduate psychology students. The function of the contingency contracting program in producing increased study rate was evaluated by individual experiments with each student in an experimental contracting group. The overall effect of the program on test performance was assessed by comparing the final scores for the course earned by the experimental group with those earned by two matched control groups. A reversal procedure established that contingency contracting did significantly increase the study rate of students of a wide range of ability. However, it was selectively effective in improving the test performance of below-average students only. Study rate gains in contracted courses did not generalize to noncontracted courses. Self-recording of study time in the absence of scheduled differential consequences did not improve test performance. Study rate under no-consequence conditions varied with test schedule. For both consequence and no-consequence groups, the correlation between study time and final score for the course was only moderate. PMID:4436175

  13. Medicare program; physician performance standard rates of increase for federal fiscal year 1991--HCFA. Notice.

    PubMed

    1990-12-28

    This notice announces the Federal fiscal year (FY) 1991 physician performance standard rates of increase for expenditures and volume of physician services under the Medicare Supplementary Medical Insurance (part B) Program as required by section 1848(f)(2)(C) of the Social Security Act as added by section 4105(d) of the Omnibus Budget Reconciliation Act of 1990. The physician performance standard rates of increase for FY 1991 are the following: 7.3 percent for all physician services, 3.3 percent for surgical services, and 8.6 percent for nonsurgical services. PMID:10108587

  14. Is the caesarean section rate a performance indicator of an obstetric unit?

    PubMed

    Singh, Ruchi; Nath Trivedi, Amarendra

    2011-02-01

    The indications of caesarean section are increasing. The need to respect maternal desire in the decision making has been supported by law and ethics. Some of the other contributors to the increasing caesarean section rate are breech with failed external cephalic version, decreasing rate of trial of scar, increasing induction rate and electronic fetal heart rate monitoring and changing demography. Despite the adverse effects of caesarean section, the incidence of severe morbidity and mortality is low. The strategies put forward to reduce the caesarean section rate (CSR) have not been effective and in no country or province, the CSR has come down. CSR should not be looked at in isolation or as high or low. It is the product of changing obstetric practice and societal norms and demographics. CSR not reflect the performance of a maternity unit. PMID:20608796

  15. Performance evaluation and effect of biogas circulation rate of a bubble column for biological desulfurization.

    PubMed

    Kobayashi, Takuro; Xu, Kai-Qin; Li, Yu-You; Inamori, Yuhei

    2012-01-01

    Biological desulfurization using a bubble column reactor was investigated in a continuous biogas treatment. Rapid biogas circulation between the digester and the bubble column for biological desulfurization was used to stimulate the gas-liquid mass transfer of H(2)S. A positive correlation between the biogas circulation rate and H(2)S removal rate was observed. Moreover, the increase in the circulation rate stimulated the O(2) mass transfer, eventually translating into an increase in sulfate production from the oxidation of H(2)S. Throughout the continuous experiment, the reactor retained sufficient levels of sulfide-oxidizing bacteria. A comparison of the results of the continuous biogas treatment and batch tests suggests that the gas-liquid mass transfer rate of H(2)S was the rate-limiting step in the biological desulfurization in the reactor, indicating that the mass transfer efficiency of H(2)S needs to be improved to enhance the desulfurization performance. PMID:22925864

  16. Sublattice counting and orbifolds

    NASA Astrophysics Data System (ADS)

    Hanany, Amihay; Orlando, Domenico; Reffert, Susanne

    2010-06-01

    Abelian orbifolds of mathbb{C}3 are known to be encoded by hexagonal brane tilings. To date it is not known how to count all such orbifolds. We fill this gap by employing number theoretic techniques from crystallography, and by making use of Polya's Enumeration Theorem. The results turn out to be beautifully encoded in terms of partition functions and Dirichlet series. The same methods apply to counting orbifolds of any toric non-compact Calabi-Yau singularity. As additional examples, we count the orbifolds of the conifold, of the L aba theories, and of mathbb{C}4.

  17. Bayesian Kernel Mixtures for Counts

    PubMed Central

    Canale, Antonio; Dunson, David B.

    2011-01-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviations from the Poisson. As a broad class of alternative models, we propose to use nonparametric mixtures of rounded continuous kernels. An efficient Gibbs sampler is developed for posterior computation, and a simulation study is performed to assess performance. Focusing on the rounded Gaussian case, we generalize the modeling framework to account for multivariate count data, joint modeling with continuous and categorical variables, and other complications. The methods are illustrated through applications to a developmental toxicity study and marketing data. This article has supplementary material online. PMID:22523437

  18. Bayesian Kernel Mixtures for Counts.

    PubMed

    Canale, Antonio; Dunson, David B

    2011-12-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviations from the Poisson. As a broad class of alternative models, we propose to use nonparametric mixtures of rounded continuous kernels. An efficient Gibbs sampler is developed for posterior computation, and a simulation study is performed to assess performance. Focusing on the rounded Gaussian case, we generalize the modeling framework to account for multivariate count data, joint modeling with continuous and categorical variables, and other complications. The methods are illustrated through applications to a developmental toxicity study and marketing data. This article has supplementary material online. PMID:22523437

  19. Weight loss and weight cycling in amateur wrestlers: implications for performance and resting metabolic rate.

    PubMed

    Horswill, C A

    1993-09-01

    Amateur wrestlers practice weight loss for ergogenic reasons. The effects of rapid weight loss on aerobic performance are adverse and profound, but the effects of anaerobic performance are equivocal. Anaerobic performance--strength and power--may be the most relevant type of performance to the wrestler. Maintenance of or even small decrements in anaerobic performance may translate into improvements in performance relative to the weight class, the factor by which wrestlers are matched for competition. During the recovery period between the official weigh-in and competition, wrestlers achieve at least partial nutritional recovery, which appears to benefit performance. Successive bouts of (a) weight loss to make weight and (b) recovery for performance lead to weight cycling. There is speculation that weight cycling may contribute to chronic glycogen depletion, reductions in fat-free weight, a decrease in resting metabolic rate, and an increase in body fat. The latter two would augment the difficulty of losing weight for subsequent weigh-ins. Most research indicates that the suppressed resting metabolic rate with weight loss in wrestlers appears to be transient, but subsequent research is needed for confirmation. PMID:8220391

  20. The average culling rate of Dutch dairy herds over the years 2007 to 2010 and its association with herd reproduction, performance and health.

    PubMed

    Nor, Norhariani Mohd; Steeneveld, Wilma; Hogeveen, Henk

    2014-02-01

    Optimising the number of replacement heifers needed will have positive economic and environmental consequences on herds that rear their own young stock. The number of heifers needed to be kept is closely related with the number of culled dairy cows in the herd. This study therefore looked at the variation that exists in culling rate and herd level factors associated with it. A dataset from 1903 dairy herds available included information at animal level (dates of culling, slaughter/death) and herd level (characteristics of reproduction, performance, health) over the years 2007 to 2010. The average culling rate for slaughter/death was used and was defined for each year as percentage of the herd size that died within 30 d after they were culled. The analysis of the association between average culling rate for slaughter/death and the characteristics of the herd was performed using a mixed model. The results showed that the average culling rate for slaughter/death was 25·4% and varied between 23% (2007) and 28% (2010). More than 70% of the herds have an average culling rate for slaughter/death of less than 30%, showing that there is room for lowering the average culling rate for slaughter/death. A higher average culling rate for slaughter/death is associated with a longer average calving interval, a higher average 305-d protein production, a higher average somatic cell count (SCC), a higher percentage of new high SCC, a more than 5% decrease in herd size, and herds that bought more than 1% of animals per year. A lower average culling rate for slaughter/death is associated with a longer average age, herds that bought less than 1% of animals per year and a more than 5% increase in herd size. In conclusion, the average culling rate for slaughter/death is associated with fertility, udder health and openness of the herd. PMID:24107585

  1. An Experimental Investigation of Leak Rate Performance of a Subscale Candidate Elastomer Docking Space Seal

    NASA Technical Reports Server (NTRS)

    Garafolo, Nicholas G.; Daniels, Christopher C.

    2011-01-01

    A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly called Engineering Development Unit (EDU58) was characterized and evaluated against the Constellation Project leak rate requirement. The EDU58 candidate seal assembly was manufactured from silicone elastomer S0383-70 vacuum molded in a metal retainer ring. Four seal designs were considered with unique characteristic heights. The leak rate performance was characterized through a mass point leak rate method by monitoring gas properties within an internal control volume. The leakage performance of the seals were described herein at representative docking temperatures of -50, +23, and +50 C for all four seal designs. Leak performance was also characterized at 100, 74, and 48 percent of full closure. For all conditions considered, the candidate seal assemblies met the Constellation Project leak rate requirement.

  2. Cognitive Performance and Heart Rate Variability: The Influence of Fitness Level

    PubMed Central

    Luque-Casado, Antonio; Zabala, Mikel; Morales, Esther; Mateo-March, Manuel; Sanabria, Daniel

    2013-01-01

    In the present study, we investigated the relation between cognitive performance and heart rate variability as a function of fitness level. We measured the effect of three cognitive tasks (the psychomotor vigilance task, a temporal orienting task, and a duration discrimination task) on the heart rate variability of two groups of participants: a high-fit group and a low-fit group. Two major novel findings emerged from this study. First, the lowest values of heart rate variability were found during performance of the duration discrimination task, compared to the other two tasks. Second, the results showed a decrement in heart rate variability as a function of the time on task, although only in the low-fit group. Moreover, the high-fit group showed overall faster reaction times than the low-fit group in the psychomotor vigilance task, while there were not significant differences in performance between the two groups of participants in the other two cognitive tasks. In sum, our results highlighted the influence of cognitive processing on heart rate variability. Importantly, both behavioral and physiological results suggested that the main benefit obtained as a result of fitness level appeared to be associated with processes involving sustained attention. PMID:23437276

  3. A Prediction Model for Community Colleges Using Graduation Rate as the Performance Indicator

    ERIC Educational Resources Information Center

    Moosai, Susan

    2010-01-01

    In this thesis a prediction model using graduation rate as the performance indicator is obtained for community colleges for three cohort years, 2003, 2004, and 2005 in the states of California, Florida, and Michigan. Multiple Regression analysis, using an aggregate of seven predictor variables, was employed in determining this prediction model.…

  4. The Relationship between Assessor/Assessee Gender and Performance Observation Ratings.

    ERIC Educational Resources Information Center

    Schuyten, Shana; Tashakkori, Abbas

    The effects of the genders of the assessor and the assessee on performance observation ratings of beginning teachers were studied in public schools in Louisiana. Data was collected in the pilot phase of the Louisiana Teacher Assessment Program for Interns, which included both teacher observation and structured interview. Of the assessees who…

  5. Psychometric Equivalence of Ratings for Repeat Examinees on a Performance Assessment for Physician Licensure

    ERIC Educational Resources Information Center

    Raymond, Mark R.; Swygert, Kimberly A.; Kahraman, Nilufer

    2012-01-01

    Although a few studies report sizable score gains for examinees who repeat performance-based assessments, research has not yet addressed the reliability and validity of inferences based on ratings of repeat examinees on such tests. This study analyzed scores for 8,457 single-take examinees and 4,030 repeat examinees who completed a 6-hour clinical…

  6. Development and Validation of a Rating Scale for Wind Jazz Improvisation Performance

    ERIC Educational Resources Information Center

    Smith, Derek T.

    2009-01-01

    The purpose of this study was to construct and validate a rating scale for collegiate wind jazz improvisation performance. The 14-item Wind Jazz Improvisation Evaluation Scale (WJIES) was constructed and refined through a facet-rational approach to scale development. Five wind jazz students and one professional jazz educator were asked to record…

  7. Impact of stocking rate and rainfall on sheep performance in a desert steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock performance is a critical indicator of grassland production systems and is influenced strongly by precipitation and stocking rates. However, these relationships require further investigation in the arid Desert Steppe region of northeastern China. We employed a randomized complete block des...

  8. Students' Grades and Ratings of Perceived Effectiveness of Behaviors Influencing Academic Performance

    ERIC Educational Resources Information Center

    Perlman, Baron; McCann, Lee I.; Prust, Adam

    2007-01-01

    We studied undergraduate psychology students' grades and their ratings of the helpfulness of behaviors related to good academic performance. On average students desired an AB (3.5 on a 4-point scale) and would have been satisfied with a B; 31% of students expressed satisfaction with a BC or lower. Overall, students averaged a BC final grade, a B…

  9. The Impact of Statistically Adjusting for Rater Effects on Conditional Standard Errors of Performance Ratings

    ERIC Educational Resources Information Center

    Raymond, Mark R.; Harik, Polina; Clauser, Brian E.

    2011-01-01

    Prior research indicates that the overall reliability of performance ratings can be improved by using ordinary least squares (OLS) regression to adjust for rater effects. The present investigation extends previous work by evaluating the impact of OLS adjustment on standard errors of measurement ("SEM") at specific score levels. In addition, a…

  10. Relationships among Student Ability, School Performance, and Fleet Supervisor Ratings for Navy "A" School Graduates.

    ERIC Educational Resources Information Center

    Freda, Jon S.; And Others

    This report evaluates the effectiveness and efficiency of individualized instruction compared to conventional instruction. The report provides information concerning relationships among student ability, school performance, and fleet supervisory ratings for 5,811 graduates of 19 Navy "A" schools and three pre-"A" school basic courses. The graduates…

  11. A Meta-Analysis of Adult-Rated Child Personality and Academic Performance in Primary Education

    ERIC Educational Resources Information Center

    Poropat, Arthur E.

    2014-01-01

    Background: Personality is reliably associated with academic performance, but personality measurement in primary education can be problematic. Young children find it difficult to accurately self-rate personality, and dominant models of adult personality may be inappropriate for children. Aims: This meta-analysis was conducted to determine the…

  12. Acute Effect of Decaffeinated Coffee on Heart Rate, Blood Pressure, and Exercise Performance in Healthy Subjects

    PubMed Central

    Prakash, Ravi; Kaushik, Vidya S.

    1988-01-01

    The effect of decaffeinated coffee on the cardiovascular exercise performance in nine healthy volunteers was evaluated in a double-blind randomized fashion. The heart rate, blood pressure, and duration of exercise were unchanged, and no arrhythmias or ischemic changes were seen on the electrocardiogram after drinking decaffeinated coffee. It was concluded that decaffeinated coffee has no discernible, acute, adverse cardiovascular effects. PMID:3339645

  13. Effects of Frustration on the Response Rate of Skid Row Alcoholics on a Performance Task

    ERIC Educational Resources Information Center

    Scorzelli, James F.; Reinke-Scorzelli, Mary

    1976-01-01

    Determines the changes that may occur in the response rates of 14 skid row alcoholics on a performance task after the introduction of a frustration operation. Results suggest a possible relationship between low frustration tolerance and the method by which these individuals tend to motivate themselves. (Author)

  14. Factor-Based Student Rating in Academic Performance in Southern Province of Rwanda

    ERIC Educational Resources Information Center

    Rulinda, Ephrard; Role, Elizabeth; Makewa, Lazarus Ndiku

    2013-01-01

    This study examined students' perception on academic performance using five-factor ratings namely, principal's instructional leadership, school climate, school facilities, teachers' effectiveness and family support. Data for this study were collected from selected Parent's Private Seventh-Day Adventist Secondary Schools (PPSDASS) in Southern…

  15. Analysis of Graduation Rates for Four-Year Colleges: A Model of Institutional Performance Using IPEDS

    ERIC Educational Resources Information Center

    Fung, Terence Yip-hung

    2010-01-01

    Under the George W. Bush U.S. presidential administration, the federal government pushed for greater accountability among institutions of higher education for educational outcomes. Graduation rate is a key performance indicator of institutional accountability. Previous researchers of student attrition focused primarily on the effects of student…

  16. Basing Performance Assessment on Behaviorally Anchored Rating Scales in Collegiate Organizations.

    ERIC Educational Resources Information Center

    Lyons, Paul R.

    The use of behaviorally anchored rating scales (BARS) as the basis of an assessment system that was designed to improve academic department chairpersons in a college of arts and sciences is described. Twenty-eight faculty members, two from each department, were asked to identify evaluative dimensions for assessing chairperson performance and to…

  17. Supervisor-Subordinate Age Dissimilarity and Performance Ratings: The Buffering Effects of Supervisory Relationship and Practice

    ERIC Educational Resources Information Center

    Van der Heijden, Beatrice I. J. M.; Scholarios, Dora; Van der Schoot, Esther; Jedrzejowicz, Piotr; Bozionelos, Nikos; Epitropaki, Olga; Knauth, Peter; Marzec, Izabela; Mikkelsen, Aslaug; Van der Heijde, Claudia

    2010-01-01

    Using 394 pairs of employees and their immediate supervisors working in the Information and Communication Technology (ICT) sector in three northern European countries, this study examined the effect of workplace moderators on the link between relational demography and supervisor ratings of performance. Directional age differences between superior…

  18. Medical audit data: counting is not enough.

    PubMed Central

    Lyons, C; Gumpert, R

    1990-01-01

    OBJECTIVE--To assess the meaningfulness of a year's worth of audit data relating to all the inpatients of one consultant general surgeon and to question the usefulness of certain outcome measures. DESIGN--Analysis of records entered on to audit computer (Dunnfile) and relating to inpatient episodes for one consultant general surgeon over one year. Data obtained were compared with ward records and the patient administration system to check their accuracy. SETTING--The three hospitals and 12 wards in Brighton health district where the surgeon admitted patients. SUBJECTS--859 Records relating to inpatient episodes from 1 January to 31 December 1988. These covered 655 main procedures and 79 secondary procedures performed at the same time. MAIN OUTCOME MEASURES--Procedures were analysed by complexity of operation (BUPA code) and grade of surgeon; complications were counted and rates constructed by surgeon and by BUPA code: returns to theatre were analysed. RESULTS--Simple counts revealed some data, such as the fact that one registrar performed more major operations (32) than the senior registrars (22 and 14), and an analysis of complications showed that he had a lower complication rate (11.4% v 20.0% and 19.4%). But the simple complication rate disclosed nothing about whether the complication was avoidable. Likewise, the number of returns to theatre needed further qualification. Analysis of data collection for February to April 1988 showed a 30% deficit of information on the audit system compared with ward records and prompted a re-examination of everyone's role in collecting data. After the year's audit there was still a 17% shortfall compared with the district's patient administration system, though some of this was accounted for by a backlog of work. CONCLUSIONS--It is difficult to ensure adequate data collection and entails everyone in an unfamiliar discipline. Connecting the audit system to the patient administration system would help. Despite the limitations of

  19. High rate response of ultra-high-performance fiber-reinforced concretes under direct tension

    SciTech Connect

    Tran, Ngoc Thanh; Tran, Tuan Kiet; Kim, Dong Joo

    2015-03-15

    The tensile response of ultra-high-performance fiber-reinforced concretes (UHPFRCs) at high strain rates (5–24 s{sup −} {sup 1}) was investigated. Three types of steel fibers, including twisted, long and short smooth steel fibers, were added by 1.5% volume content in an ultra high performance concrete (UHPC) with a compressive strength of 180 MPa. Two different cross sections, 25 × 25 and 25 × 50 mm{sup 2}, of tensile specimens were used to investigate the effect of the cross section area on the measured tensile response of UHPFRCs. Although all the three fibers generated strain hardening behavior even at high strain rates, long smooth fibers produced the highest tensile resistance at high rates whereas twisted fiber did at static rate. The breakages of twisted fibers were observed from the specimens tested at high strain rates unlike smooth steel fibers. The tensile behavior of UHPFRCs at high strain rates was clearly influenced by the specimen size, especially in post-cracking strength.

  20. The Study of an Integrated Rating System for Supplier Quality Performance in the Semiconductor Industry

    NASA Astrophysics Data System (ADS)

    Lee, Yu-Cheng; Yen, Tieh-Min; Tsai, Chih-Hung

    This study provides an integrated model of Supplier Quality Performance Assesment (SQPA) activity for the semiconductor industry through introducing the ISO 9001 management framework, Importance-Performance Analysis (IPA) Supplier Quality Performance Assesment and Taguchi`s Signal-to-Noise Ratio (S/N) techniques. This integrated model provides a SQPA methodology to create value for all members under mutual cooperation and trust in the supply chain. This method helps organizations build a complete SQPA framework, linking organizational objectives and SQPA activities to optimize rating techniques to promote supplier quality improvement. The techniques used in SQPA activities are easily understood. A case involving a design house is illustrated to show our model.

  1. Heart rate, anxiety and performance of residents during a simulated critical clinical encounter: a pilot study

    PubMed Central

    2014-01-01

    Background High-fidelity patient simulation has been praised for its ability to recreate lifelike training conditions. The degree to which high fidelity simulation elicits acute emotional and physiologic stress among participants – and the influence of acute stress on clinical performance in the simulation setting – remain areas of active exploration. We examined the relationship between residents’ self-reported anxiety and a proxy of physiologic stress (heart rate) as well as their clinical performance in a simulation exam using a validated assessment of non-technical skills, the Ottawa Crisis Resource Management Global Rating Scale (Ottawa GRS). Methods This was a prospective observational cohort study of emergency medicine residents at a single academic center. Participants managed a simulated clinical encounter. Anxiety was assessed using a pre- and post-simulation survey, and continuous cardiac monitoring was performed on each participant during the scenario. Performance in the simulation scenario was graded by faculty raters using a critical actions checklist and the Ottawa GRS instrument. Results Data collection occurred during the 2011 academic year. Of 40 eligible residents, 34 were included in the analysis. The median baseline heart rate for participants was 70 beats per minute (IQR: 62 – 78). During the simulation, the median maximum heart rate was 140 beats per minute (IQR: 137 – 151). The median minimum heart rate during simulation was 81 beats per minute (IQR: 72 – 92), and mean heart rate was 117 beats per minute (95% CI: 111 – 123). Pre- and post-simulation anxiety scores were equal (mean 3.3, IQR: 3 to 4). The minimum and maximum Overall Ottawa GRS scores were 2.33 and 6.67, respectively. The median Overall score was 5.63 (IQR: 5.0 to 6.0). Of the candidate predictors of Overall performance in a multivariate logistic regression model, only PGY status showed statistical significance (P = 0.02). Conclusions Simulation is associated

  2. Inventory count strategies.

    PubMed

    Springer, W H

    1996-02-01

    An important principle of accounting is that asset inventory needs to be correctly valued to ensure that the financial statements of the institution are accurate. Errors is recording the value of ending inventory in one fiscal year result in errors to published financial statements for that year as well as the subsequent fiscal year. Therefore, it is important that accurate physical counts be periodically taken. It is equally important that any system being used to generate inventory valuation, reordering or management reports be based on consistently accurate on-hand balances. At the foundation of conducting an accurate physical count of an inventory is a comprehensive understanding of the process coupled with a written plan. This article presents a guideline of the physical count processes involved in a traditional double-count approach. PMID:10165241

  3. Calorie count - Alcoholic beverages

    MedlinePlus

    ... want to watch how much you drink. Cocktails mixed with soda, cream, or ice cream can have especially high calorie counts. If you find you are having trouble cutting back on alcohol , talk with your doctor. Here is a list ...

  4. Blood Count Tests

    MedlinePlus

    Your blood contains red blood cells (RBC), white blood cells (WBC), and platelets. Blood count tests measure the number and types of cells in your blood. This helps doctors check on your overall health. ...

  5. Blood Count Tests

    MedlinePlus

    ... white blood cells (WBC), and platelets. Blood count tests measure the number and types of cells in ... helps doctors check on your overall health. The tests can also help to diagnose diseases and conditions ...

  6. Counting Knights and Knaves

    ERIC Educational Resources Information Center

    Levin,Oscar; Roberts, Gerri M.

    2013-01-01

    To understand better some of the classic knights and knaves puzzles, we count them. Doing so reveals a surprising connection between puzzles and solutions, and highlights some beautiful combinatorial identities.

  7. The impact of a specific blend of essential oil components and sodium butyrate in feed on growth performance and Salmonella counts in experimentally challenged broilers.

    PubMed

    Cerisuelo, A; Marín, C; Sánchez-Vizcaíno, F; Gómez, E A; de la Fuente, J M; Durán, R; Fernández, C

    2014-03-01

    Essential oils (EO) and short-chain fatty acids have potential antimicrobial activity in broilers. This study aimed to investigate the effect of a specific blend of EO and a combination of this blend of EO with sodium-butyrate on growth performance and Salmonella colonization in broilers. A total of 480 one-day-old male broilers were distributed into 5 treatments (8 pens per treatment and 12 birds per pen) and reared during 42 d in experimental conditions. Dietary treatments consisted of the addition of different doses of EO (0 mg/kg, control; 50 mg/kg, EO50 and 100 mg/kg, EO100) or a combination of EO with 1 g/kg of sodium-butyrate (B; EO50 + B, EOB50 and EO100 + B, EOB100) to a basal diet. All birds were orally infected with 10(8) cfu of Salmonella Enteritidis on d 7 of study. Individual BW and feed intake per pen were measured at arrival and on a weekly basis. The prevalence and enumeration of Salmonella in feces was determined per treatment at 72 h postinfection and on d 23 and 37 of study. At slaughter, cecal content and liver samples from 16 birds per treatment were cultured for Salmonella and cecal pH was measured. No differences were observed on growth performance among treatments. All fecal samples analyzed were positive for Salmonella from d 10 to the end of the rearing period. At slaughter, Salmonella contamination (positive samples) in cecum was lower in birds fed EOB50 compared with the other treatments (P < 0.05), whereas birds fed the control diet showed the highest colonization rates. The pH of the cecal content was not different among treatments. Thus, EO or its combination with sodium-butyrate did not affect growth performance. However, a clear effectiveness of these products was observed in Salmonella control, especially when low doses of EO were combined with sodium-butyrate (EOB50). PMID:24604853

  8. Energy dispersive photon counting detectors for breast imaging

    NASA Astrophysics Data System (ADS)

    Barber, William C.; Wessel, Jan C.; Malakhov, Nail; Wawrzyniak, Gregor; Hartsough, Neal E.; Gandhi, Thulasidharan; Nygard, Einar; Iwanczyk, Jan S.

    2013-09-01

    We report on our efforts toward the development of silicon (Si) strip detectors for energy-resolved clinical breast imaging. Typically, x-ray integrating detectors based on scintillating cesium iodide CsI(Tl) or amorphous selenium (a- Se) are used in most commercial systems. Recently, mammography instrumentation has been introduced based on photon counting silicon Si strip detectors. Mammography requires high flux from the x-ray generator, therefore, in order to achieve energy resolved single photon counting, a high output count rate (OCR) for the detector must be achieved at the required spatial resolution and across the required dynamic range for the application. The required performance in terms of the OCR, spatial resolution, and dynamic range must be obtained with sufficient field of view (FOV) for the application thus requiring the tiling of pixel arrays and scanning techniques. Room temperature semiconductors, operating as direct conversion x-ray sensors, can provide the required speed when connected to application specific integrated circuits (ASICs) operating at fast peaking times with multiple fixed thresholds per pixel, provided that the sensors are designed for rapid signal formation across the x-ray energy ranges of the application at the required energy and spatial resolutions. We present our methods and results from the optimization of prototype detectors based on Si strip structures. We describe the detector optimization and the development of ASIC readout electronics that provide the required spatial resolution, low noise, high count rate capabilities and minimal power consumption.

  9. The effects of scene content parameters, compression, and frame rate on the performance of analytics systems

    NASA Astrophysics Data System (ADS)

    Tsifouti, A.; Triantaphillidou, S.; Larabi, M. C.; Doré, G.; Bilissi, E.; Psarrou, A.

    2015-01-01

    In this investigation we study the effects of compression and frame rate reduction on the performance of four video analytics (VA) systems utilizing a low complexity scenario, such as the Sterile Zone (SZ). Additionally, we identify the most influential scene parameters affecting the performance of these systems. The SZ scenario is a scene consisting of a fence, not to be trespassed, and an area with grass. The VA system needs to alarm when there is an intruder (attack) entering the scene. The work includes testing of the systems with uncompressed and compressed (using H.264/MPEG-4 AVC at 25 and 5 frames per second) footage, consisting of quantified scene parameters. The scene parameters include descriptions of scene contrast, camera to subject distance, and attack portrayal. Additional footage, including only distractions (no attacks) is also investigated. Results have shown that every system has performed differently for each compression/frame rate level, whilst overall, compression has not adversely affected the performance of the systems. Frame rate reduction has decreased performance and scene parameters have influenced the behavior of the systems differently. Most false alarms were triggered with a distraction clip, including abrupt shadows through the fence. Findings could contribute to the improvement of VA systems.

  10. Review of recycling performance indicators: a study on collection rate in Taiwan.

    PubMed

    Wen, Lihchyi; Lin, Chun-Hsu; Lee, Soo-Cheol

    2009-08-01

    The Taiwan Environmental Protection Administration (Taiwan EPA) launched a national Extended Producer Responsibility (EPR) system after integrating eight private recycling organizations in 1998. After that, the environmental performance of the EPR system brought a lot of attention to policy makers. Many studies show positive environmental effects of the EPR system in Taiwan. However, there are controversial questions remained, such as whether the performance indicators used are the right choice to estimate the environmental effects of the recycling policy? Can those estimated results really reflect the performance of the system? This paper would therefore like to more accurately evaluate the performance indicators of the EPR system based on data observed over the past decade in Taiwan. In the process of evaluating the performance indicators, we have found that the collection rates for durable goods are often ignored in countries that pursue a zero waste policy. This may affect the actual recycling outcome and resource direction targeted by producers. However, in order for the collection rate to be adopted as a policy indicator, how to estimate the amounts of retired or waste products during a period is critical. In this paper, we estimate the collection rate for electrical and electronic waste by using the survival analysis and ownership data analysis approaches. We also provide a comparison of both approaches and put forward suggestions for directions in the future in solid waste management. PMID:19398319

  11. Self-rated right-left confusability and performance on the Money Road-Map Test.

    PubMed

    Yamashita, Hikari

    2013-09-01

    This study assessed the relationship between self-rated right-left confusability and performance on the Money Road-Map Test (MRMT). Eighty-six undergraduate university students (44 women and 42 men) rated right-left subjective confusability using a questionnaire, and then completed the MRMT. Low- and high-confusability groups were determined using self-rated confusability scores. The high-confusability participants were less accurate and slower than the low-confusability participants in completing the MRMT. Self-confusability ratings significantly correlated with both accuracy scores and completion times on the MRMT. Although, women showed a significantly greater inclination than men to judge themselves as being more prone to confusion in right-left discrimination, the male advantage was not observed in terms of accuracy of response: there was a significant difference only in the completion time on the MRMT. PMID:22965921

  12. High rate Li/SOCl(2) cells. 2. Effect of catalyst on cell performance

    NASA Astrophysics Data System (ADS)

    Kilroy, W. P.; Pitts, L.; Abraham, K. M.

    1985-04-01

    As part of the ongoing High Energy Batteries for Weapons Programs at NSWC, various cell parameters were investigated to examine their effect on the performance, safety, and chemistry of Li/SOCl2 cells. This report summarizes the influence of cobalt dibenzo-tetraazaannulene (Co-TAA) cataylsis on the discharge and overdischarge chemistry and performance of spirally wound commercial C-size cells. Co-TAA catalyst improved the performance and safety of C-size Li/SOCl2 cells. The catalyst was most effective at high rate or low temperature operation. The presence of water increased the risk of hazards at high rates of discharge. The generation of gases such as COS, CS2, HCl, etc. was dependent on the internal temperature.

  13. Power plant performance monitoring and improvement. Volume 2. Incremental heat rate sensitivity analysis

    SciTech Connect

    Crim, H.G.

    1986-02-01

    This report describes the interim findings of the Incremental Heat Rate Sensitivity Analysis task of EPRI Project RP1681-1/2153-1, Power Plant Performance Instrumentation System. Objectives of this task were to develop the models and methods for evaluation of unit performance uncertainty, and to determine the effects of modeling, input/output, and fuel cost uncertainty on production cost and dispatch. Analyses and simulations were made to determine the sensitivity of cost and economic dispatch to modeling errors and measurement errors within realistic system constraints. The results obtained are sufficient to provide the measures necessary to evaluate on-line updates of unit performance to develop incremental heat rate information for economic dispatch.

  14. HgCdTe APD-based linear-mode photon counting components and ladar receivers

    NASA Astrophysics Data System (ADS)

    Jack, Michael; Wehner, Justin; Edwards, John; Chapman, George; Hall, Donald N. B.; Jacobson, Shane M.

    2011-05-01

    Linear mode photon counting (LMPC) provides significant advantages in comparison with Geiger Mode (GM) Photon Counting including absence of after-pulsing, nanosecond pulse to pulse temporal resolution and robust operation in the present of high density obscurants or variable reflectivity objects. For this reason Raytheon has developed and previously reported on unique linear mode photon counting components and modules based on combining advanced APDs and advanced high gain circuits. By using HgCdTe APDs we enable Poisson number preserving photon counting. A metric of photon counting technology is dark count rate and detection probability. In this paper we report on a performance breakthrough resulting from improvement in design, process and readout operation enabling >10x reduction in dark counts rate to ~10,000 cps and >104x reduction in surface dark current enabling long 10 ms integration times. Our analysis of key dark current contributors suggest that substantial further reduction in DCR to ~ 1/sec or less can be achieved by optimizing wavelength, operating voltage and temperature.

  15. Base Rates of Social Skills Acquisition/Performance Deficits, Strengths, and Problem Behaviors: An Analysis of the Social Skills Improvement System-Rating Scales

    ERIC Educational Resources Information Center

    Gresham, Frank M.; Elliott, Stephen N.; Kettler, Ryan J.

    2010-01-01

    Base rate information is important in clinical assessment because one cannot know how unusual or typical a phenomenon is without first knowing its base rate in the population. This study empirically determined the base rates of social skills acquisition and performance deficits, social skills strengths, and problem behaviors using a nationally…

  16. MEASUREMENT OF DRUG-PROTEIN DISSOCIATION RATES BY HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY AND PEAK PROFILING

    PubMed Central

    Schiel, John E.; Ohnmacht, Corey M.; Hage, David S.

    2012-01-01

    The rate at which a drug or other small solute interacts with a protein is important in understanding the biological and pharmacokinetic behavior of these agents. One approach that has been developed for examining these rates involves the use of high-performance affinity chromatography (HPAC) and estimates of band-broadening through peak profiling. Previous work with this method has been based on a comparison of the statistical moments for a retained analyte versus non-retained species at a single, high flow rate to obtain information on stationary phase mass transfer. In this study an alternative approach was created that allows a broad range of flow rates to be used for examining solute-protein dissociation rates. Chromatographic theory was employed to derive equations that could be used with this approach on a single column, as well as with multiple columns to evaluate and correct for the impact of stagnant mobile phase mass transfer. The interaction of L-tryptophan with human serum albumin was used as a model system to test this method. A dissociation rate constant of 2.7 (± 0.2) s−1 was obtained by this approach at pH 7.4 and 37°C, which was in good agreement with previous values determined by other methods. The techniques described in this report can be applied to other biomolecular systems and should be valuable for the determination of drug-protein dissociation rates. PMID:19422253

  17. Supervisor-subordinate age dissimilarity and performance ratings: the buffering effects of supervisory relationship and practice.

    PubMed

    Van der Heijden, Beatrice I J M; Scholarios, Dora; Van der Schoot, Esther; Jedrzejowicz, Piotr; Bozionelos, Nikos; Epitropaki, Olga; Knauth, Peter; Marzec, Izabela; Mikkelsen, Aslaug; Van der Heijde, Claudia

    2010-01-01

    Using 394 pairs of employees and their immediate supervisors working in the Information and Communication Technology (ICT) sector in three northern European countries, this study examined the effect of workplace moderators on the link between relational demography and supervisor ratings of performance. Directional age differences between superior and subordinate (i.e., status incongruence caused when the supervisor is older or younger than his/her subordinate) and non-directional age differences were used as predictors of supervisor ratings of occupational expertise. The quality of the supervisor-subordinate relationship and the existence of positive age-related supervisory practices were examined as moderators of this relationship. The results provide no support for a relationship between directional age differences and age-related stereotyping by supervisors in ratings of performance, neither for the effects of age-related supervisory practices. However, high quality supervisor-subordinate relationships did moderate the effects of age dissimilarity on supervisory ratings. The implications of these findings for performance appraisal methodologies and recommendations for further research are discussed. PMID:21174640

  18. Heart failure performance measures: do they have an impact on 30-day readmission rates?

    PubMed

    Mazimba, Sula; Grant, Nakash; Parikh, Analkumar; Mwandia, George; Makola, Diklar; Chilomo, Christine; Redko, Cristina; Hahn, Harvey S

    2013-01-01

    Congestive heart failure (CHF) accounts for more health care costs than any other diagnosis. Readmissions contribute to this expenditure. The authors evaluated the relationship between adherence to performance metrics and 30-day readmissions. This was a retrospective study of 6063 patients with CHF between 2001 and 2008. Data were collected for 30-day readmissions and compliance with CHF performance measures at discharge. Rates of readmission for CHF increased from 16.8% in 2002 to 24.8% in 2008. Adherence to performance measures increased concurrently from 95.8% to 99.9%. Except for left ventricular function (LVF) assessment, the 30-day readmission rate was not associated with adherence to performance measures. Readmitted patients had twice the odds of not having their LVF assessed (odds ratio = 2.0; P < .00005; 95% confidence interval = 1.45-2.63). CHF performance measures, except for the LVF assessment, have little relationship to 30-day readmissions. Further studies are needed to identify performance measures that correlate with quality of care. PMID:23110998

  19. Rates of surgical site infection as a performance measure: Are we ready?

    PubMed

    Biscione, Fernando Martín

    2009-11-30

    With the introduction of quality assurance in health care delivery, there has been a proliferation of research studies that compare patient outcomes for similar conditions among many health care delivery facilities. Since the 1990s, increasing interest has been placed in the incorporation of clinical adverse events as quality indicators in hospital quality assurance programs. Adverse post-operative events, and very especially surgical site infection (SSI) rates after specific procedures, gained popularity as hospital quality indicators in the 1980s. For a SSI rate to be considered a valid indicator of the quality of care, it is essential that a proper adjustment for patient case mix be performed, so that meaningful comparisons of SSI rates can be made among surgeons, institutions, or over time. So far, a significant impediment to developing meaningful hospital-acquired infection rates that can be used for intra- and inter-hospital comparisons has been the lack of an adequate means of adjusting for case mix. This paper discusses what we have learned in the last years regarding risk adjustment of SSI rates for provider performance assessment, and identifies areas in which significant improvement is still needed. PMID:21160789

  20. Novel Photon-Counting Detectors for Free-Space Communication

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Yang, Guan; Sun, Xiaoli; Lu, Wei; Merritt, Scott; Beck, Jeff

    2016-01-01

    We present performance data for novel photon counting detectors for free space optical communication. NASA GSFC is testing the performance of three novel photon counting detectors 1) a 2x8 mercury cadmium telluride avalanche array made by DRS Inc. 2) a commercial 2880 silicon avalanche photodiode array and 3) a prototype resonant cavity silicon avalanche photodiode array. We will present and compare dark count, photon detection efficiency, wavelength response and communication performance data for these detectors. We discuss system wavelength trades and architectures for optimizing overall communication link sensitivity, data rate and cost performance. The HgCdTe APD array has photon detection efficiencies of greater than 50 were routinely demonstrated across 5 arrays, with one array reaching a maximum PDE of 70. High resolution pixel-surface spot scans were performed and the junction diameters of the diodes were measured. The junction diameter was decreased from 31 m to 25 m resulting in a 2x increase in e-APD gain from 470 on the 2010 array to 1100 on the array delivered to NASA GSFC. Mean single photon SNRs of over 12 were demonstrated at excess noise factors of 1.2-1.3.The commercial silicon APD array has a fast output with rise times of 300ps and pulse widths of 600ps. Received and filtered signals from the entire array are multiplexed onto this single fast output. The prototype resonant cavity silicon APD array is being developed for use at 1 micron wavelength.

  1. Novel photon-counting detectors for free-space communication

    NASA Astrophysics Data System (ADS)

    Krainak, M. A.; Yang, G.; Sun, X.; Lu, W.; Merritt, S.; Beck, J.

    2016-03-01

    We present performance data for novel photon-counting detectors for free space optical communication. NASA GSFC is testing the performance of three types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We present and compare dark count, photon-detection efficiency, wavelength response and communication performance data for these detectors. We discuss system wavelength trades and architectures for optimizing overall communication link sensitivity, data rate and cost performance. The HgCdTe APD array routinely demonstrated photon detection efficiencies of greater than 50% across 5 arrays, with one array reaching a maximum PDE of 70%. We performed high-resolution pixel-surface spot scans and measured the junction diameters of its diodes. We found that decreasing the junction diameter from 31 μm to 25 μm doubled the e- APD gain from 470 for an array produced in the year 2010 to a gain of 1100 on an array delivered to NASA GSFC recently. The mean single-photon SNR was over 12 and the excess noise factors measurements were 1.2-1.3. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output.

  2. False-positive rates associated with the use of multiple performance and symptom validity tests.

    PubMed

    Larrabee, Glenn J

    2014-06-01

    Performance validity test (PVT) error rates using Monte Carlo simulation reported by Berthelson and colleagues (in False positive diagnosis of malingering due to the use of multiple effort tests. Brain Injury, 27, 909-916, 2013) were compared with PVT and symptom validity test (SVT) failure rates in two nonmalingering clinical samples. At a per-test false-positive rate of 10%, Monte Carlo simulation overestimated error rates for: (i) failure of ≥2 out of 5 PVTs/SVT for Larrabee (in Detection of malingering using atypical performance patterns on standard neuropsychological tests. The Clinical Neuropsychologist, 17, 410-425, 2003) and ACS (Pearson, Advanced clinical solutions for use with WAIS-IV and WMS-IV. San Antonio: Pearson Education, 2009) and (ii) failure of ≥2 out of 7 PVTs/SVT for Larrabee (Detection of malingering using atypical performance patterns on standard neuropsychological tests. The Clinical Neuropsychologist, 17, 410-425, 2003; Malingering scales for the Continuous Recognition Memory Test and Continuous Visual Memory Test. The Clinical Neuropsychologist, 23, 167-180, 2009 combined). Monte Carlo overestimation is likely because PVT performances are atypical in pattern or degree for what occurs in actual neurologic, psychiatric, or developmental disorders. Consequently, PVT scores form skewed distributions with performance at ceiling and restricted range, rather than forming a standard normal distribution with mean of 0 and standard deviation of 1.0. These results support the practice of using ≥2 PVT/SVT failures as representing probable invalid clinical presentation. PMID:24769887

  3. Point count length and detection of forest neotropical migrant birds

    USGS Publications Warehouse

    Dawson, D.K.; Smith, D.R.; Robbins, C.S.

    1995-01-01

    Comparisons of bird abundances among years or among habitats assume that the rates at which birds are detected and counted are constant within species. We use point count data collected in forests of the Mid-Atlantic states to estimate detection probabilities for Neotropical migrant bird species as a function of count length. For some species, significant differences existed among years or observers in both the probability of detecting the species and in the rate at which individuals are counted. We demonstrate the consequence that variability in species' detection probabilities can have on estimates of population change, and discuss ways for reducing this source of bias in point count studies.

  4. Conflicting Readmission Rate Trends in a High-Risk Population: Implications for Performance Measurement

    PubMed Central

    Vann, Julie C. Jacobson; Jackson, Carlos T.

    2015-01-01

    Abstract The 30-day readmission rate is a common performance indicator for hospitals and accountable care entities. There is reason to question whether measuring readmissions as a function of hospital discharges is an appropriate measure of performance for initiatives that aim to improve overall cost and quality outcomes in a population. The objectives of this study were to compare trends in 30-day readmission rates per discharge to population-based measures of hospital admission and readmission frequency in a high-risk statewide Medicaid population over a 5-year period of quality improvement and care management intervention. Further, this study aimed to examine case-mix changes among hospitalized beneficiaries over time. This was a retrospective analysis of North Carolina Medicaid paid claims 2008 through 2012 for beneficiaries with multiple chronic or catastrophic conditions. Thirty-day readmission rates per discharge trended upward from 18.3% in 2008 to 18.7% in 2012. However, the rate of 30-day readmissions per 1000 beneficiaries declined from 123.3 to 110.7. Overall inpatient admissions per 1000 beneficiaries decreased from 579.4 to 518.5. The clinical complexity of hospitalized patients increased over the 5-year period. Although rates of hospital admissions and readmissions fell substantially in this high-risk population over 5 years, the 30-day readmission rate trend appeared unfavorable when measured as a percent of hospital discharges. This may be explained by more complex patients requiring hospitalization over time. The choice of metrics significantly affects the perceived effectiveness of improvement initiatives. Emphasis on readmission rates per discharge may be misguided for entities with a population health management focus. (Population Health Management 2015;18:351–357) PMID:25607449

  5. Particle Energy Spectrum, Revisited from a Counting Statistics Perspective

    SciTech Connect

    2012-07-28

    In nuclear science, gamma and neutron spectra are counted energy by energy, and then particle by particle. Until recently, few studies have been performed on how exactly those energy spectra are counted, or how those counts are correlated. Because of lack of investigation, cross section covariance and correlation matrices are usually estimated using perturbation method. We will discuss a statistical counting scheme that shall mimic the gamma and neutron counting process used in nuclear science. From this counting scheme, the cross section covariance and correlation can be statistically derived.

  6. TVFMCATS. Time Variant Floating Mean Counting Algorithm

    SciTech Connect

    Huffman, R.K.

    1999-05-01

    This software was written to test a time variant floating mean counting algorithm. The algorithm was developed by Westinghouse Savannah River Company and a provisional patent has been filed on the algorithm. The test software was developed to work with the Val Tech model IVB prototype version II count rate meter hardware. The test software was used to verify the algorithm developed by WSRC could be correctly implemented with the vendor`s hardware.

  7. Time Variant Floating Mean Counting Algorithm

    Energy Science and Technology Software Center (ESTSC)

    1999-06-03

    This software was written to test a time variant floating mean counting algorithm. The algorithm was developed by Westinghouse Savannah River Company and a provisional patent has been filed on the algorithm. The test software was developed to work with the Val Tech model IVB prototype version II count rate meter hardware. The test software was used to verify the algorithm developed by WSRC could be correctly implemented with the vendor''s hardware.

  8. Characterizing (rating) the performance of large photovoltaic arrays for all operating conditions

    SciTech Connect

    King, D.L.; Eckert, P.E.

    1996-06-01

    A new method has been developed for characterizing the electrical performance of photovoltaic arrays. The method provides both a ``rating`` at standard reporting conditions and a rigorous yet straightforward model for predicting array performance at all operating conditions. For the first time, the performance model handles the influences of irradiance, module temperature, solar spectrum, solar angle-of-incidence, and temperature coefficients, in a practical way. Validity of the procedure was confirmed during field testing of a 25-kW array recently installed by Arizona Public Service Co. on Carol Spring Mountain (which powers microwave, ceullular phone, and TV communictions equipment). This paper describes the characterization procedure, measured array performance, and the predictive model.

  9. Testing for trend with count data.

    PubMed

    Weller, E A; Ryan, L M

    1998-06-01

    Among the tests that can be used to detect dose-related trends in count data from toxicological studies are nonparametric tests such as the Jonckheere-Terpstra and likelihood-based tests, for example, based on a Poisson model. This paper was motivated by a data set of tumor counts in which conflicting conclusions were obtained using these two tests. To define situations where one test may be preferable, we compared the small and large sample performance of these two tests as well as a robust and conditional version of the likelihood-based test in the absence and presence of a dose-related trend for both Poisson and overdispersed Poisson data. Based on our results, we suggest using the Poisson test when little overdispersion is present in the data. For more overdispersed data, we recommend using the robust Poisson test for highly discrete data (response rate lower than 2-3) and the robust Poisson test or the Jonckheere-Terpstra test for moderately discrete or continuous data (average responses larger than 2 or 3). We also studied the effects of dose metameter misspecification. A clear effect on efficiency was seen when the 'wrong' dose metameter was used to compute the test statistic. In general, unless there is strong reason to do otherwise, we recommend the use of equally spaced dose levels when applying the Poisson or robust Poisson test for trend. PMID:9629655

  10. The effect of heart rate variability biofeedback on performance psychology of basketball players.

    PubMed

    Paul, Maman; Garg, Kanupriya

    2012-06-01

    Coping with pressure and anxiety is an ineluctable demand of sports performance. Heart rate variability (HRV) Biofeedback (BFB) shall be used as a tool for self regulating physiological responses resulting in improved psycho physiological interactions. For further analysis, the present study has been designed to examine the relationship between anxiety and performance and also effectiveness of biofeedback protocol to create stress-eliciting situation in basketball players. Thirty basketball players of university level and above (both male and female) aged 18-28 years, who scored a minimum of 20 in state trait anxiety inventory, were randomly divided into three equal groups- Experimental (Biofeedback) group, Placebo group and Control (No Treatment) group. The BFB group received HRV BFB training for 10 consecutive days for 20 min that included breathing at individual's resonant frequency through a pacing stimulus; Placebo group was shown motivational video clips for 10 consecutive days for 10 min, whereas No Treatment Control group was not given any intervention. Two way repeated measure ANOVA was applied to analyze the differences within and between the groups. Anxiety, coping self-efficacy, heart rate variability, respiration rate, and performance (dribbling, passing and shooting) at session 1, 10 and 1 month follow up were statistically significant in each group along with interaction of group and time (p < 0.001). Also, all the measures showed statistically significant inter group difference (p < 0.05). The findings are harmonious with existing data on HRV BFB as a strategy for dealing with anxiety. The Placebo group showed improvement in self efficacy and performance post training. The Control group showed no change in any variable except performance. The results of the study support the idea that HRV BFB lowers the anxiety and thus there seems to be a potential association between HRV BFB and performance optimization. PMID:22402913

  11. A preliminary study on the association between ventilation rates in classrooms and student performance.

    PubMed

    Shaughnessy, R J; Haverinen-Shaughnessy, U; Nevalainen, A; Moschandreas, D

    2006-12-01

    Poor conditions leading to substandard indoor air quality (IAQ) in classrooms have been frequently cited in the literature over the past two decades. However, there is limited data linking poor IAQ in the classrooms to student performance. Whereas, it is assumed that poor IAQ results in reduced attendance and learning potential, and subsequent poor student performance, validating this hypothesis presents a challenge in today's school environment. This study explores the association between student performance on standardized aptitude tests that are administered to students on a yearly basis, to classroom carbon dioxide (CO2) concentrations, which provide a surrogate of ventilation being provided to each room. Data on classroom CO2 concentrations (over a 4-5 h time span within a typical school day) were recorded in fifth grade classrooms in 54 elementary schools within a school district in the USA. Results from this preliminary study yield a significant (P < 0.10) association between classroom-level ventilation rate and test results in math. They also indicate that non-linear effects may need to be considered for better representation of the association. A larger sample size is required in order to draw more definitive conclusions. Practical Implications Future studies could focus on (1) gathering more evidence on the possible association between classroom ventilation rates and students' academic performance; (2) the linear/non-linear nature of the association; and (3) whether it is possible to detect 'no observed adverse effect level' for adequate ventilation with respect to academic performance in schools. All of this information could be used to improve guidance and take regulatory actions to ensure adequate ventilation in schools. The high prevalence of low ventilation rates, combined with the growing evidence of the positive impact that sufficient ventilation has on human performance, suggests an opportunity for improving design and management of school

  12. Influence of frame rate and image delay on virtual driving performance.

    PubMed

    Sudarsan, S P; Du, L Q; Cobb, P N; Yager, E S; Jacobus, C J

    1997-01-01

    The control and navigation of unmanned ground vehicles (UGVs) by humans requires a thorough understanding of the limitations in human perception and performance. Images of the external world recorded by cameras mounted on the UGV are presented as a video display to the operator, who then remotely manipulates the vehicle using a standard control. Operator performance is directly proportional to the computational complexity associated with the processing of video data. This work studies the effects of frame rate and image delay (lag) on remote driving performance. Experiments were conducted with five subjects using a driving simulator with a 1 dof force feedback steering wheel control. After sufficient training on the simulator, subjects drove a virtual car on a standard track under varying settings of frame rate and lag. Performance was measured by the duration to complete the course. Comparison of performance both within and between subjects showed characteristic driving patterns at different settings. Implications of the findings are discussed in relation to video data presentation for remote driving applications. PMID:9731360

  13. Metals processing control by counting molten metal droplets

    DOEpatents

    Schlienger, Eric; Robertson, Joanna M.; Melgaard, David; Shelmidine, Gregory J.; Van Den Avyle, James A.

    2000-01-01

    Apparatus and method for controlling metals processing (e.g., ESR) by melting a metal ingot and counting molten metal droplets during melting. An approximate amount of metal in each droplet is determined, and a melt rate is computed therefrom. Impedance of the melting circuit is monitored, such as by calculating by root mean square a voltage and current of the circuit and dividing the calculated current into the calculated voltage. Analysis of the impedance signal is performed to look for a trace characteristic of formation of a molten metal droplet, such as by examining skew rate, curvature, or a higher moment.

  14. Failure rate analysis of Goddard Space Flight Center spacecraft performance during orbital life

    NASA Technical Reports Server (NTRS)

    Norris, H. P.; Timmins, A. R.

    1976-01-01

    Space life performance data on 57 Goddard Space Flight Center spacecraft are analyzed from the standpoint of determining an appropriate reliability model and the associated reliability parameters. Data from published NASA reports, which cover the space performance of GSFC spacecraft launched in the 1960-1970 decade, form the basis of the analyses. The results of the analyses show that the time distribution of 449 malfunctions, of which 248 were classified as failures (not necessarily catastrophic), follow a reliability growth pattern that can be described with either the Duane model or a Weibull distribution. The advantages of both mathematical models are used in order to: identify space failure rates, observe chronological trends, and compare failure rates with those experienced during the prelaunch environmental tests of the flight model spacecraft.

  15. Fast counting electronics for neutron coincidence counting

    DOEpatents

    Swansen, James E.

    1987-01-01

    An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a .sup.3 He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output ) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

  16. Fast counting electronics for neutron coincidence counting

    DOEpatents

    Swansen, J.E.

    1985-03-05

    An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a /sup 3/He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

  17. Calculating inspector probability of detection using performance demonstration program pass rates

    NASA Astrophysics Data System (ADS)

    Cumblidge, Stephen; D'Agostino, Amy

    2016-02-01

    The United States Nuclear Regulatory Commission (NRC) staff has been working since the 1970's to ensure that nondestructive testing performed on nuclear power plants in the United States will provide reasonable assurance of structural integrity of the nuclear power plant components. One tool used by the NRC has been the development and implementation of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI Appendix VIII[1] (Appendix VIII) blind testing requirements for ultrasonic procedures, equipment, and personnel. Some concerns have been raised, over the years, by the relatively low pass rates for the Appendix VIII qualification testing. The NRC staff has applied statistical tools and simulations to determine the expected probability of detection (POD) for ultrasonic examinations under ideal conditions based on the pass rates for the Appendix VIII qualification tests for the ultrasonic testing personnel. This work was primarily performed to answer three questions. First, given a test design and pass rate, what is the expected overall POD for inspectors? Second, can we calculate the probability of detection for flaws of different sizes using this information? Finally, if a previously qualified inspector fails a requalification test, does this call their earlier inspections into question? The calculations have shown that one can expect good performance from inspectors who have passed appendix VIII testing in a laboratory-like environment, and the requalification pass rates show that the inspectors have maintained their skills between tests. While these calculations showed that the PODs for the ultrasonic inspections are very good under laboratory conditions, the field inspections are conducted in a very different environment. The NRC staff has initiated a project to systematically analyze the human factors differences between qualification testing and field examinations. This work will be used to evaluate and prioritize

  18. Autonomic response to tactical pistol performance measured by heart rate variability.

    PubMed

    Thompson, Andrew G; Swain, David P; Branch, J David; Spina, Robert J; Grieco, Carmine R

    2015-04-01

    This study evaluated changes in autonomic tone during a tactical pistol competition. At rest and during a match, heart rate variability (HRV) was examined in 28 healthy subjects. Heart rate variability time-domain variables (including interbeat interval [IBI]) and frequency-domain variables (low frequency [LF], high frequency [HF], total power [TP]) measured during shooting were subtracted from those measured during rest to produce Δs. The shooting task involved several, rapid tactical maneuvers. Raw time to completion and inaccurate shots (points down [PDs]) were recorded and combined to form a match score where lower values indicated superior shooting performance. Mean (±SD) raw time was 135.9 ± 34.1 seconds, PDs were 78 ± 34, and match score was 175.3 ± 39.8. Shooting decreased IBI (i.e., increased heart rate) and LF. ΔLF, ΔHF, and ΔTP were independent of ΔIBI. Raw time was significantly (p ≤ 0.05) correlated to shooting IBI (r = 0.404) and ΔIBI (r = -0.426). Points down were significantly correlated to ΔTP (r = 0.416) and ΔLF (r = 0.376). Match score was significantly correlated to ΔIBI (r = -0.458), ΔHF (r = 0.467), ΔLF (r = 0.377), and ΔTP (r = 0.451). In conclusion, individuals with a greater decrease in IBI (and thus heart rate) performed better by accomplishing the match faster. Individuals with less change in stress-related HRV measures (LF, HF, and TP) performed better through improved accuracy. Thus, HRV-derived sympathetic response is significantly related to shooting performance and should be used to assess marksmanship effectiveness under duress. PMID:25029000

  19. Reproductive performance of high growth rate gilts inseminated at an early age.

    PubMed

    Kummer, Rafael; Bernardi, Mari Lourdes; Wentz, Ivo; Bortolozzo, Fernando Pandolfo

    2006-11-01

    The aim of this work was to determine if gilts, which have a high growth rate (GR) could be mated earlier without reducing the reproductive performance or increasing the culling rate up to the third parity. Gilts of Camborough 22 (C22, n=568) breeding were mated and allocated into three groups according to weight and age on the insemination day. G1 (n=164)-gilts with a GR>or=700 g/d and inseminated at <210 d. G2 (n=165)-gilts with a GR>or=700 g/d and inseminated at >or=210 d. G3 (n=239)-gilts with a GR<700 g/d and inseminated at >or=210 d. All females were fed ad libitum from 150 d on and were inseminated at their second estrus or later. The minimum weight at mating was 127 kg. Three parities were studied, with farrowing rate, litter size and culling rate being compared. At the first parity, G2 gilts produced, on average, one more piglet than the other groups (P<0.05). However, when analyzing three parities, there were no differences in total born (11.6 x 12.3 x 11.7), farrowing rate (87.1% x 88.7% x 89.8%) and culling rate (30.2% x 25.3% x 28.2%) among G1-G3 groups, respectively (P>0.05). In conclusion, gilts, which had a minimum weight of 127 kg can be inseminated at their second or greater estrus, between 185 and <210 d of age, without impairing their productive performance over three parities. PMID:16431043

  20. Swimming performance, metabolic rates, and their correlates in the Iceland scallop Chlamys islandica.

    PubMed

    Tremblay, Isabelle; Guderley, Helga E; Frechette, Marcel

    2006-01-01

    The dramatic escape response of some scallops is modified by reproductive investment and by acclimation temperature. Despite considerable knowledge of the physiology of the escape response, functional links between escape response performance, organismal rates of oxygen uptake, and tissue metabolic capacities are little known. We measured oxygen consumption rates (standard, maximal, and aerobic scope), escape behavior (initial and repeat performance), tissue mass, condition index, protein content, and tissue metabolic capacities in the Iceland scallop Chlamys islandica to examine links between these parameters. Postexercise oxygen consumption rates were positively linked to contraction rate (repeat test) and to pyruvate kinase activity in the adductor muscle but negatively linked to digestive gland wet mass. Swimming behavior was mainly related to activity of glycolytic enzymes, and enzymatic activities were related to anatomic parameters. Scallop behavior and physiology change with size, both within our samples and on a larger scale. Small scallops showed more intense swimming activity and had higher arginine kinase activities but lower glycolytic enzyme activities in their adductor muscle than larger scallops. This corresponds to the ontogenetic change in susceptibility to predation and in habitat use observed in C. islandica. PMID:17041870

  1. The Effects of a Ninth Grade Academy on Dropout Rates, Attendance Rates, and Academic Performance of Ninth-Grade Students

    ERIC Educational Resources Information Center

    Cole, Partricka L.

    2013-01-01

    This study investigated data from 5 high schools in West Tennessee. The study examined whether a ninth-grade transition program (i.e., the Ninth-grade Academy) had an effect on student achievement and engagement, which was measured by English I End-of-Course Test Scores, attendance rates, and dropout rates. All of the schools were treatment…

  2. Whose interests count?

    PubMed

    Brudney, Daniel; Lantos, John D

    2014-10-01

    Whose interests should count and how should various interests be balanced at the pediatric patient's bedside? The interests of the child patient clearly count. Recently, however, many authors have argued that the family's interests also count. But how should we think about the interests of others? What does it mean to talk about "the family" in this context? Does it really just mean the interests of each individual family member? Or is the family itself a moral entity that has interests of its own independent of the interests of each of its members? Are such interests important only as they affect the patient's interest or also for their own sake? In this special supplement to Pediatrics, a group of pediatricians, philosophers, and lawyers grapple with these questions. They examine these issues from different angles and reach different conclusions. Jointly, they demonstrate the ethical importance and, above all, the ethical complexity of the family's role at the bedside. PMID:25274878

  3. Effect of Firing Rate on the Performance of Shock Wave Lithotriptors

    PubMed Central

    Pishchalnikov, Yuri A.; McAteer, James A.; Williams, James C.

    2008-01-01

    Objective To determine the mechanism that underlies the effect of shock wave (SW) rate on the performance of clinical lithotripters. Materials and Methods The effect of firing rate on the pressure characteristics of SWs was assessed using a fiber-optic probe hydrophone (FOPH 500, RP Acoustics, Leutenbach, Germany). Shock waves were fired at slow (5−27 SW/min) and fast (100−120 SW/min) rates using a conventional high-pressure lithotriptor (DoLi-50, Dornier MedTech America, Inc., Kennesaw, GA, USA), and a new low-pressure lithotriptor (XX-ES, Xi Xin Medical Instruments Co. Ltd, Suzhou, PRC). A digital camcorder (HDR-HC3, Sony, Japan) was used to record cavitation fields, and an ultrafast multiframe high-speed camera (Imacon 200, DRS Data & Imaging Systems, Inc., Oakland, NJ, USA) was used to follow the evolution of bubbles throughout the cavitation cycle. Results Firing rate had little effect on the leading positive-pressure phase of the SWs with the DoLi lithotriptor. A slight reduction (∼7%) of peak positive pressure (P +) was detected only in the very dense cavitation fields (∼1000 bubbles/cm3) generated at the fastest firing rate (120 SW/min) in nondegassed water. The negative pressure of the SWs, on the other hand, was dramatically affected by firing rate. At 120 SW/min the peak negative pressure was reduced by ∼84%, the duration and area of the negative pressure component was reduced by ∼80% and ∼98%, respectively, and the energy density of negative pressure was reduced by > 99%. Whereas cavitation bubbles proliferated at fast firing rates, HS-camera images showed the bubbles that persisted between SWs were very small (< 10 μm). Similar results were obtained with the XX-ES lithotriptor but only after recognizing a rate-dependent charging artefact with that machine. Conclusion Increasing the firing rate of a lithotriptor can dramatically reduce the negative pressure component of the SWs, while the positive pressure remains virtually unaffected

  4. Performance monitoring following total sleep deprivation: effects of task type and error rate.

    PubMed

    Renn, Ryan P; Cote, Kimberly A

    2013-04-01

    There is a need to understand the neural basis of performance deficits that result from sleep deprivation. Performance monitoring tasks generate response-locked event-related potentials (ERPs), generated from the anterior cingulate cortex (ACC) located in the medial surface of the frontal lobe that reflect error processing. The outcome of previous research on performance monitoring during sleepiness has been mixed. The purpose of this study was to evaluate performance monitoring in a controlled study of experimental sleep deprivation using a traditional Flanker task, and to broaden this examination using a response inhibition task. Forty-nine young adults (24 male) were randomly assigned to a total sleep deprivation or rested control group. The sleep deprivation group was slower on the Flanker task and less accurate on a Go/NoGo task compared to controls. General attentional impairments were evident in stimulus-locked ERPs for the sleep deprived group: P300 was delayed on Flanker trials and smaller to Go-stimuli. Further, N2 was smaller to NoGo stimuli, and the response-locked ERN was smaller on both tasks, reflecting neurocognitive impairment during performance monitoring. In the Flanker task, higher error rate was associated with smaller ERN amplitudes for both groups. Examination of ERN amplitude over time showed that it attenuated in the rested control group as error rate increased, but such habituation was not apparent in the sleep deprived group. Poor performing sleep deprived individuals had a larger Pe response than controls, possibly indicating perseveration of errors. These data provide insight into the neural underpinnings of performance failure during sleepiness and have implications for workplace and driving safety. PMID:23384887

  5. Exploring individual quality: Basal metabolic rate and reproductive performance in storm-petrels

    USGS Publications Warehouse

    Blackmer, A.L.; Mauck, R.A.; Ackerman, J.T.; Huntington, C.E.; Nevitt, G.A.; Williams, J.B.

    2005-01-01

    Despite evidence that some individuals achieve both superior reproductive performance and high survivorship, the factors underlying variation in individual quality are not well understood. The compensation and increased-intake hypotheses predict that basal metabolic rate (BMR) influences reproductive performance; if so, variation in BMR may be related to differences in individual quality. We evaluated whether BMR measured during the incubation period provides a proximate explanation for variation in individual quality by measuring the BMRs and reproductive performance of Leach's storm-petrels (Oceanodroma leucorhoa) breeding on Kent Island, New Brunswick, Canada, during 2000 and 2001. We statistically controlled for internal (body mass, breeding age, sex) and external (year, date, time of day) effects on BMR. We found that males with relatively low BMRs hatched their eggs earlier in the season and that their chicks' wing growth rates were faster compared to males with relatively high BMRs. Conversely, BMR was not related to egg volume, hatching date, or chick growth rate for females or to lifetime (???23 years) hatching success for either sex. Thus, for males but not for females, our results support the compensation hypothesis. This hypothesis predicts that animals with low BMRs will achieve better reproductive performance than animals with high BMRs because they have lower self-maintenance costs and therefore can apportion more energy to reproduction. These results provide evidence that intraspecific variation in reproductive performance is related to BMR and suggest that BMR may influence individual quality in males. ?? The Author 2005. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

  6. Photon Counting Detectors for the 1.0 - 2.0 Micron Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.

    2004-01-01

    We describe results on the development of greater than 200 micron diameter, single-element photon-counting detectors for the 1-2 micron wavelength range. The technical goals include quantum efficiency in the range 10-70%; detector diameter greater than 200 microns; dark count rate below 100 kilo counts-per-second (cps), and maximum count rate above 10 Mcps.

  7. Single Photon Counting Detectors for Low Light Level Imaging Applications

    NASA Astrophysics Data System (ADS)

    Kolb, Kimberly

    2015-10-01

    This dissertation presents the current state-of-the-art of semiconductor-based photon counting detector technologies. HgCdTe linear-mode avalanche photodiodes (LM-APDs), silicon Geiger-mode avalanche photodiodes (GM-APDs), and electron-multiplying CCDs (EMCCDs) are compared via their present and future performance in various astronomy applications. LM-APDs are studied in theory, based on work done at the University of Hawaii. EMCCDs are studied in theory and experimentally, with a device at NASA's Jet Propulsion Lab. The emphasis of the research is on GM-APD imaging arrays, developed at MIT Lincoln Laboratory and tested at the RIT Center for Detectors. The GM-APD research includes a theoretical analysis of SNR and various performance metrics, including dark count rate, afterpulsing, photon detection efficiency, and intrapixel sensitivity. The effects of radiation damage on the GM-APD were also characterized by introducing a cumulative dose of 50 krad(Si) via 60 MeV protons. Extensive development of Monte Carlo simulations and practical observation simulations was completed, including simulated astronomical imaging and adaptive optics wavefront sensing. Based on theoretical models and experimental testing, both the current state-of-the-art performance and projected future performance of each detector are compared for various applications. LM-APD performance is currently not competitive with other photon counting technologies, and are left out of the application-based comparisons. In the current state-of-the-art, EMCCDs in photon counting mode out-perform GM-APDs for long exposure scenarios, though GM-APDs are better for short exposure scenarios (fast readout) due to clock-induced-charge (CIC) in EMCCDs. In the long term, small improvements in GM-APD dark current will make them superior in both long and short exposure scenarios for extremely low flux. The efficiency of GM-APDs will likely always be less than EMCCDs, however, which is particularly disadvantageous for

  8. Muscle Energy Stores and Stroke Rates of Emperor Penguins: Implications for Muscle Metabolism and Dive Performance

    PubMed Central

    Williams, Cassondra L.; Sato, Katsufumi; Shiomi, Kozue; Ponganis, Paul J.

    2016-01-01

    In diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. During complete ischemia, ATP production is dependent on the size of the myoglobin oxygen (O2) store and the concentrations of phosphocreatine (PCr) and glycogen (Gly). Therefore, we measured PCr and Gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle O2 and those energy stores under conditions of complete ischemia and a previously determined muscle metabolic rate. We also analyzed stroke rate to assess muscle workload variation during dives and evaluate potential limitations on the model. Measured PCr and Gly concentrations, 20.8 and 54.6 mmol kg−1, respectively, were similar to published values for non-diving animals. The model demonstrated that PCr and Gly provide a large anaerobic energy store, even for dives longer than 20 min. Stroke rate varied throughout the dive profile indicating muscle workload was not constant during dives as was assumed in the model. The stroke rate during the first 30 seconds of dives increased with increased dive depth. In extremely long dives, lower overall stroke rates were observed. Although O2 consumption and energy store depletion may vary during dives, the model demonstrated that PCr and Gly, even at concentrations typical of terrestrial birds and mammals, are a significant anaerobic energy store and can play an important role in the emperor penguin’s ability to perform long dives. PMID:22418705

  9. Effects of flicker rate, complexity, and color combinations of Chinese characters and backgrounds on visual search performance with varying flicker types.

    PubMed

    Huang, Kuo-Chen; Lin, Rung-Tai; Wu, Chih-Fu

    2011-08-01

    This study investigated the effects of number of strokes in Chinese characters, flicker rate, flicker type, and character/background color combination on search performance. 37 participants ages 14 to 18 years were randomly assigned to each flicker-type condition. The search field contained 36 characters arranged in a 6 x 6 matrix. Participants were asked to search for the target characters among the surrounding distractors and count how many target characters were displayed in the search array. Analysis indicated that the character/background color combination significantly affected search times. The color combinations of white/purple and white/green yielded search times greater than those for black/white and black/yellow combinations. A significant effect for flicker type on search time was also identified. Rotating characters facilitated search time, compared with twinkling ones. The number of strokes and the flicker rates also had positive effects on search performances. For flicker rate, the search accuracy for 0.5 Hz was greater than that for 1.0 Hz, and the latter was also greater than that for 2.0 Hz. Results are applicable to web advertisement designs containing dynamic characters, in terms of how to best capture readers' attention by various means of dynamic character presentation. PMID:21987920

  10. Methodological Study of a Single Photon Counting Pixel Detector at SPring-8

    SciTech Connect

    Toyokawa, H.; Suzuki, M.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Huelsen, G.; Kraft, P.

    2007-01-19

    PILATUS (Pixel Apparatus for the SLS) is a challenging project to develop a large area single photon counting pixel detector for synchrotron radiation experiments. SPring-8 examined the PLATUS single module detectors in collaboration with the Paul Scherrer Institute. The PILATUS-II single module detector has a desired performance with almost zero defective pixels and a fast frame rate up to 100 Hz using a newly developed PCI readout system on a Linux-PC. The maximum counting rate achieves more than 2 x 106 X-rays/s/pixel.

  11. Performance assessments for radioactive waste repositories; the rate of movement of faults

    USGS Publications Warehouse

    Trask, Newell J.

    1982-01-01

    Performance assessments of mined repositories for radioactive waste require estimates of the likelihood of fault movements and earthquakes that may affect the repository and its surrounding ground water flow system. Some previous assessments have attempted to estimate the rate of formation of new faults; some have relied heavily on historic seismicity or the time of latest movement on faults. More appropriate emphasis is on the identification of faults that have been active or may have been active under the present teconic regime in a broad region and on estimates of the long-term rate of movement of such faults. Faults that have moved under the current stress field, even at low rates, are likely to move again during the time the wastes will remain toxic. A continuum exists for the present rate of movement of faults which ranges from 10 mm per year for obviously active faults along the western margin of the North American plate to as low as 10 -4 mm per year for recently documented faults in the Atlantic Coast province. On the basis of regional consistency in movement rates and constraints imposed by geomorphology, I derive upper bounds for the rates of occurrence of fault offsets for various crustal stress provinces in the conterminous United States. These upper bounds are not meant to substitute for detailed studies of specific faults and seismicity at specific sites. They can help to reduce the considerable uncertainty that attaches to all estimates of future tectonic activity. The principal uncertainty in their estimation is the manner in which total slip across faults is distributed among discrete events especially in regions in which the rate of movement is very low.

  12. High rate capacitive performance of single-walled carbon nanotube aerogels

    SciTech Connect

    Van Aken, Katherine L.; Pérez, Carlos R.; Oh, Youngseok; Beidaghi, Majid; Joo Jeong, Yeon; Islam, Mohammad F.; Gogotsi, Yury

    2015-05-30

    Single-walled carbon nanotube (SWCNT) aerogels produced by critical-point-drying of wet-gel precursors exhibit unique properties, such as high surface-area-to-volume and strength-to-weight ratios. They are free-standing, are binder-free, and can be scaled to thicknesses of more than 1 mm. In this paper, we examine the electric double layer capacitive behavior of these materials using a common room temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI). Electrochemical performance is assessed through galvanostatic cycling, cyclic voltammetry and impedance spectroscopy. Results indicate stable capacitive performance over 10,000 cycles as well as an impressive performance at high charge and discharge rates, due to accessible pore networks and enhanced electronic and ionic conductivities of SWCNT aerogels. Finally, these materials can find applications in mechanically compressible and flexible supercapacitor devices with high power requirements.

  13. High rate capacitive performance of single-walled carbon nanotube aerogels

    DOE PAGESBeta

    Van Aken, Katherine L.; Pérez, Carlos R.; Oh, Youngseok; Beidaghi, Majid; Joo Jeong, Yeon; Islam, Mohammad F.; Gogotsi, Yury

    2015-05-30

    Single-walled carbon nanotube (SWCNT) aerogels produced by critical-point-drying of wet-gel precursors exhibit unique properties, such as high surface-area-to-volume and strength-to-weight ratios. They are free-standing, are binder-free, and can be scaled to thicknesses of more than 1 mm. In this paper, we examine the electric double layer capacitive behavior of these materials using a common room temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI). Electrochemical performance is assessed through galvanostatic cycling, cyclic voltammetry and impedance spectroscopy. Results indicate stable capacitive performance over 10,000 cycles as well as an impressive performance at high charge and discharge rates, due to accessible pore networks andmore » enhanced electronic and ionic conductivities of SWCNT aerogels. Finally, these materials can find applications in mechanically compressible and flexible supercapacitor devices with high power requirements.« less

  14. Magnetically aligned graphite electrodes for high-rate performance Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Billaud, Juliette; Bouville, Florian; Magrini, Tommaso; Villevieille, Claire; Studart, André R.

    2016-08-01

    As lithium-ion batteries become ubiquitous, the energy storage market is striving for better performance, longer lifetime and better safety of the devices. This race for performance is often focused on the search for new materials, whereas less effort has been dedicated to the electrode engineering. Enhancing the power density by increasing the amount of active material remains impractical since it impinges the transport of ions across the electrode during the charging and discharging processes. Here, we show that the electrochemical performance of a battery containing a thick (about 200 μm), highly loaded (about 10 mg cm‑2) graphite electrode can be remarkably enhanced by fabricating anodes with an out-of-plane aligned architecture using a low external magnetic field. The lower tortuosity resulting from such a simple and scalable magnetic alignment approach leads to a specific charge up to three times higher than that of non-architectured electrodes at a rate of 1C.

  15. Rats' performance on variable-interval schedules with a linear feedback loop between response rate and reinforcement rate.

    PubMed Central

    Reed, Phil; Hildebrandt, Tom; DeJongh, Julie; Soh, Mariane

    2003-01-01

    Three experiments investigated whether rats are sensitive to the molar properties of a variable-interval (VI) schedule with a positive relation between response rate and reinforcement rate (i.e., a VI+ schedule). In Experiment 1, rats responded faster on a variable ratio (VR) schedule than on a VI+ schedule with an equivalent feedback function. Reinforced interresponse times (IRTs) were shorter on the VR as compared to the VI+ schedule. In Experiments 2 and 3, there was no systematic difference in response rates maintained by a VI+ schedule and a VI schedule yoked in terms of reinforcement rate. This was found both when the yoking procedure was between-subject (Experiment 2) and within-subject (Experiment 3). Mean reinforced IRTs were similar on both the VI+ and yoked VI schedules, but these values were more variable on the VI+ schedule. These results provided no evidence that rats are sensitive to the feedback function relating response rate to reinforcement rate on a VI+ schedule. PMID:12822684

  16. Making Research Count

    ERIC Educational Resources Information Center

    Appleby, Yvon; Kerwin, Marie; McCulloch, Sue

    2008-01-01

    Making research count in the education sector is often difficult to achieve as people, quite properly, question its relevance, purpose and impact. One of the significant barriers to research supporting practice in the lifelong learning sector is that funded research carried out in higher education institutions is frequently privileged above…

  17. LOW ENERGY COUNTING CHAMBERS

    DOEpatents

    Hayes, P.M.

    1960-02-16

    A beta particle counter adapted to use an end window made of polyethylene terephthalate was designed. The extreme thinness of the film results in a correspondingly high transmission of incident low-energy beta particles by the window. As a consequence, the counting efficiency of the present counter is over 40% greater than counters using conventional mica end windows.

  18. Counting digital filters

    NASA Technical Reports Server (NTRS)

    Zohar, S. (Inventor)

    1973-01-01

    Several embodiments of a counting digital filter of the non-recursive type are disclosed. In each embodiment two registers, at least one of which is a shift register, are included. The shift register received j sub x-bit data input words bit by bit. The kth data word is represented by the integer.

  19. What Counts as Evidence?

    ERIC Educational Resources Information Center

    Dougherty Stahl, Katherine A.

    2014-01-01

    Each disciplinary community has its own criteria for determining what counts as evidence of knowledge in their academic field. The criteria influence the ways that a community's knowledge is created, communicated, and evaluated. Situating reading, writing, and language instruction within the content areas enables teachers to explicitly…

  20. Designing high-performance electrochemical energy-storage nanoarchitectures to balance rate and capacity.

    PubMed

    Sassin, Megan B; Hoag, Cheyne P; Willis, Bradley T; Kucko, Nathan W; Rolison, Debra R; Long, Jeffrey W

    2013-02-21

    The impressive specific capacitance and high-rate performance reported for many nanometric charge-storing films on planar substrates cannot impact a technology space beyond microdevices unless such performance translates into a macroscale form factor. In this report, we explore how the nanoscale-to-macroscale properties of the electrode architecture (pore size/distribution, void volume, thickness) define energy and power performance when scaled to technologically relevant dimensions. Our test bed is a device-ready electrode architecture in which scalable, manufacturable carbon nanofoam papers with tunable pore sizes (5-200 nm) and thickness (100-300 μm) are painted with ~10 nm coatings of manganese oxide (MnOx). The quantity of capacitance and the rate at which it is delivered for four different MnOx-C variants was assessed by fabricating symmetric electrochemical capacitors using a concentrated aqueous electrolyte. Carbon nanofoam papers containing primarily 10-20 nm mesopores support high MnOx loadings (60 wt%) and device-level capacitance (30 F g(-1)), but the small mesoporous network hinders electrolyte transport and the low void volume restricts the quantity of charge-compensating ions within the electrode, making the full capacitance only accessible at slow rates (5 mV s(-1)). Carbon nanofoam papers with macropores (100-200 nm) facilitate high rate operation (50 mV s(-1)), but deliver significantly lower device capacitance (13 F g(-1)) as a result of lower MnOx loadings (41 wt%). Devices comprising MnOx-carbon nanofoams with interconnecting networks of meso- and macropores balance capacitance and rate performance, delivering 33 F g(-1) at 5 mV s(-1) and 23 F g(-1) at 50 mV s(-1). The use of carbon nanofoam papers with size-tunable pore structures and thickness provides the opportunity to engineer the electrode architecture to deliver scalable quantities of capacitance (F cm(-2)) in tens of seconds with a single device. PMID:23334529

  1. Blink rate during tests of executive performance after nocturnal traffic noise.

    PubMed

    Breimhorst, Markus; Marks, Anke; Robens, Sibylle; Griefahn, Barbara

    2009-01-01

    This analysis is on the hypothesis that nocturnal traffic noise affects sleep quality whereas performance decrement is avoided by increased effort expressed by a decrease in blink rates (BRs) during a visual task. Twenty-four persons (12 women, 12 men; 19-28 years, 23.56+/-2.49 years) slept during three consecutive weeks in the laboratory while exposed to road, rail, or aircraft noise with weekly permuted changes. Each week consisted of a random sequence of a quiet night (32 dBA) and three nights with equivalent noise levels of 39, 44 and 50 dBA respectively. The polysomnogram was recorded during all nights. Every morning the participants rated their sleep quality and then completed two executive tasks (Go/Nogo-, Switch-task). Neither of the two performance tests was affected by nocturnal noise. Sleep efficiency and subjective sleep quality decreased with increasing noise levels but were not associated with the type of noise. In contrast, BRs were associated with the type of noise, not with noise levels. The results do not support the hypothesis concerning the BR. The possible reasons are discussed. However, the results do not exclude that other physiological parameters such as heart rate or brain potentials measured during the tests might have revealed alterations associated with nocturnal noise exposure. PMID:19805931

  2. Rate Effects on Timing, Key Velocity, and Finger Kinematics in Piano Performance

    PubMed Central

    Dalla Bella, Simone; Palmer, Caroline

    2011-01-01

    We examined the effect of rate on finger kinematics in goal-directed actions of pianists. In addition, we evaluated whether movement kinematics can be treated as an indicator of personal identity. Pianists' finger movements were recorded with a motion capture system while they performed melodies from memory at different rates. Pianists' peak finger heights above the keys preceding keystrokes increased as tempo increased, and were attained about one tone before keypress. These rate effects were not simply due to a strategy to increase key velocity (associated with tone intensity) of the corresponding keystroke. Greater finger heights may compensate via greater tactile feedback for a speed-accuracy tradeoff that underlies the tendency toward larger temporal variability at faster tempi. This would allow pianists to maintain high temporal accuracy when playing at fast rates. In addition, finger velocity and accelerations as pianists' fingers approached keys were sufficiently unique to allow pianists' identification with a neural-network classifier. Classification success was higher in pianists with more extensive musical training. Pianists' movement “signatures” may reflect unique goal-directed movement kinematic patterns, leading to individualistic sound. PMID:21731615

  3. Graphene/carbon black hybrid film for flexible and high rate performance supercapacitor

    NASA Astrophysics Data System (ADS)

    Wang, Yaming; Chen, Junchen; Cao, Jianyun; Liu, Yan; Zhou, Yu; Ouyang, Jia-Hu; Jia, Dechang

    2014-12-01

    Reduced graphene oxide/carbon black (rGO/CB) hybrid films with different carbon black (CB) contents are prepared by a simple vacuum filtration method. The CB particles evenly distribute between the graphene layers, not only preventing the compact restack of rGO sheets but also providing electrical contact between the base planes of rGO sheets. As expected, the as-prepared rGO/CB hybrid film shows enhanced rate capability when compared with rGO film. Furthermore, a solid-state flexible supercapacitor has been constructed with the optimized rGO/CB hybrid film by using polyvinyl alcohol (PVA)/H2SO4 gel as electrolyte and Au coated PET film as current collector and mechanical support. The solid-state flexible supercapacitor shows a specific capacitance of 112 F g-1 at a scan rate of 5 mV s-1, and excellent rate performance with a specific capacitance of 79.6 F g-1 at a high scan rate of 1 V s-1. Moreover, the flexible solid-state supercapacitor exhibits good cycling stability with capacitance retention of 94% after 3000 cycles in normal state plus 2000 cycles in bent state.

  4. Rational Design of Cathode Structure for High Rate Performance Lithium-Sulfur Batteries.

    PubMed

    Chen, Hongwei; Wang, Changhong; Dai, Yafei; Qiu, Shengqiang; Yang, Jinlong; Lu, Wei; Chen, Liwei

    2015-08-12

    Practical applications of Li-S batteries require not only high specific capacities and long cycle lifetimes but also high rate performance. We report a rationally designed Li-S cathode, which consists of a freestanding composite thin film assembled from S nanoparticles, reduced graphene oxide (rGO), and a multifunctional additive poly(anthraquinonyl sulfide) (PAQS). The S nanoparticles provide a high initial specific capacity, and the layered and porous rGO structure provides electron and ion transport paths and restricts polysulfide shuttling. PAQS is not only a highly efficient sulfide trapping agent but also an excellent Li(+) conductor, which benefits the battery reaction kinetics at a high rate. The resulting cathode exhibits an initial specific capacity of 1255 mAh g(-1) with a decay rate as low as 0.046% per cycles over 1200 cycles. Importantly, it displays a reversible capacity of 615 mAh g(-1) when discharged at a high rate of 8 C (13.744 A g(-1)). PMID:26148126

  5. Rate effects on timing, key velocity, and finger kinematics in piano performance.

    PubMed

    Bella, Simone Dalla; Palmer, Caroline

    2011-01-01

    We examined the effect of rate on finger kinematics in goal-directed actions of pianists. In addition, we evaluated whether movement kinematics can be treated as an indicator of personal identity. Pianists' finger movements were recorded with a motion capture system while they performed melodies from memory at different rates. Pianists' peak finger heights above the keys preceding keystrokes increased as tempo increased, and were attained about one tone before keypress. These rate effects were not simply due to a strategy to increase key velocity (associated with tone intensity) of the corresponding keystroke. Greater finger heights may compensate via greater tactile feedback for a speed-accuracy tradeoff that underlies the tendency toward larger temporal variability at faster tempi. This would allow pianists to maintain high temporal accuracy when playing at fast rates. In addition, finger velocity and accelerations as pianists' fingers approached keys were sufficiently unique to allow pianists' identification with a neural-network classifier. Classification success was higher in pianists with more extensive musical training. Pianists' movement "signatures" may reflect unique goal-directed movement kinematic patterns, leading to individualistic sound. PMID:21731615

  6. Monitoring performance of the cameras under the high dose-rate gamma ray environments.

    PubMed

    Cho, Jai Wan; Choi, Young Soo; Jeong, Kyung Min

    2014-05-01

    CCD/CMOS cameras, loaded on a robot system, are generally used as the eye of the robot and monitoring unit. A major problem that arises when dealing with images provided by CCD/CMOS cameras under severe accident situations of a nuclear power plant is the presence of speckles owing to the high dose-rate gamma irradiation fields. To use a CCD/CMOS camera as a monitoring unit in a high radiation area, the legibility of the camera image in such intense gamma-radiation fields should therefore be defined. In this paper, the authors describe the monitoring index as a figure of merit of the camera's legibleness under a high dose-rate gamma ray irradiation environment. From a low dose-rate (10 Gy h) to a high dose-rate (200 Gy h) level, the legible performances of the cameras owing to the speckles are evaluated. The numbers of speckles generated by gamma ray irradiation in the camera image are calculated by an image processing technique. The legibility of the sensor indicator (thermo/hygrometer) owing to the number of speckles is also presented. PMID:24667385

  7. Failure to uncover the effects of unconscious symbiotic fantasies on heart rate and fine motor performance.

    PubMed

    Malik, R; Apel, S; Nelham, C; Rutkowski, C; Ladd, H

    1997-12-01

    18 men and 18 women were tachistoscopically shown the stimuli MOMMY AND I ARE ONE, DADDY AND I ARE ONE, and MYMMO NAD I REA ENO, at subjective thresholds (subliminal condition) and at 500 msec. (supraliminal condition). Following exposure to each stimulus, subjects performed a fine motor line-tracing task. Heart rate was monitored continuously during stimulus presentation and the fine motor task. Analysis showed subjects did not respond more positively with decreased heart rate or fewer errors on the fine motor task following the MOMMY message than the anagram phrase, thereby providing no support for the hypotheses. No correlation was found between responsiveness to the MOMMY message and scores on measures of self-perception and kinship. In the light of mounting negative evidence, the validity of the method of subliminal psychodynamic activation is questioned. PMID:9450275

  8. Design and Performance of the Acts Gigabit Satellite Network High Data-Rate Ground Station

    NASA Technical Reports Server (NTRS)

    Hoder, Doug; Kearney, Brian

    1995-01-01

    The ACTS High Data-Rate Ground stations were built to support the ACTS Gigabit Satellite Network (GSN). The ACTS GSN was designed to provide fiber-compatible SONET service to remote nodes and networks through a wideband satellite system. The ACTS satellite is unique in its extremely wide bandwidth, and electronically controlled spot beam antennas. This paper discusses the requirements, design and performance of the RF section of the ACTS High Data-Rate Ground Stations and constituent hardware. The ACTS transponder systems incorporate highly nonlinear hard limiting. This introduced a major complexity in to the design and subsequent modification of the ground stations. A discussion of the peculiarities of the A CTS spacecraft transponder system and their impact is included.

  9. The role of reactant unmixedness, strain rate, and length scale on premixed combustor performance

    SciTech Connect

    Samuelsen, S.; LaRue, J.; Vilayanur, S.; Guillaume, D.

    1995-12-31

    Lean premixed combustion provides a means to reduce pollutant formation and increase combustion efficiency. However, fuel-air mixing is rarely uniform in space and time. This nonuniformity in concentration will lead to relative increases in pollutant formation and decreases in combustion efficiency. The nonuniformity of the concentration at the exit of the premixer has been defined by Lyons (1981) as the ``unmixedness.`` Although turbulence properties such as length scales and strain rate are known to effect unmixedness, the exact relationship is unknown. Evaluating this relationship and the effect of unmixedness in premixed combustion on pollutant formation and combustion efficiency are an important part of the overall goal of US Department of Energy`s Advanced Turbine System (ATS) program and are among the goals of the program described herein. The information obtained from ATS is intended to help to develop and commercialize gas turbines. The contributions to the program which the University of California (Irvine) Combustion Lab (UCICL) will provide are: (1) establish the relationship of inlet unmixedness, length scales, and mean strain rate to performance, (2) determine the optimal levels of inlet unmixedness, length scales, and mean strain rates to maximize combustor performance, and (3) identify efficient premixing methods for achieving the necessary inlet conditions. The program during this reporting period is focused on developing a means to measure and qualify different degrees of temporal and spatial unmixedness. Laser diagnostic methods for planer unmixedness measurements are being developed and preliminary results are presented herein. These results will be used to (1), aid in the design of experimental premixers, and (2), determine the unmixedness which will be correlated with the emissions of the combustor. This measure of unmixedness coupled with length scale, strain rate and intensity information is required to attain the UCI goals.

  10. Winter-time CO2 addition in high rate algal mesocosms for enhanced microalgal performance.

    PubMed

    Sutherland, Donna L; Montemezzani, Valerio; Mehrabadi, Abbas; Craggs, Rupert J

    2016-02-01

    Carbon limitation in domestic wastewater high rate algal ponds is thought to constrain microalgal photo-physiology and productivity and CO2 augmentation is often used to overcome this limitation in summer. However, the implications of carbon limitation during winter are poorly understood. This paper investigates the effects of 0.5%, 2%, 5% and 10% CO2 addition on the winter-time performance of wastewater microalgae in high rate algal mesocosms. Performance was measured in terms of light absorption, photosynthetic efficiency, biomass production and nutrient removal rates, along with community composition. Varying percentage CO2 addition and associated change in culture pH resulted in 3 distinct microalgal communities. Light absorption by the microalgae increased by up to 144% with CO2 addition, while a reduction in the package effect meant that there was less internal self-shading thereby increasing the efficiency of light absorption. Carbon augmentation increased the maximum rate of photosynthesis by up to 172%, which led to increased microalgal biovolume by up to 181% and an increase in total organic biomass for all treatments except 10% CO2. While 10% CO2 improved light absorption and photosynthesis this did not translate to enhanced microalgal productivity. Increased microalgal productivity with CO2 addition did not result in increased dissolved nutrient (nitrogen and phosphorus) removal. This experiment demonstrated that winter-time carbon augmentation up to 5% CO2 improved microalgal light absorption and utilisation, which ultimately increased microalgal biomass and is likely to enhance total annual microalgal areal productivity in HRAPs. PMID:26707731

  11. Three-Dimensional Tubular MoS2/PANI Hybrid Electrode for High Rate Performance Supercapacitor.

    PubMed

    Ren, Lijun; Zhang, Gaini; Yan, Zhe; Kang, Liping; Xu, Hua; Shi, Feng; Lei, Zhibin; Liu, Zong-Huai

    2015-12-30

    By using three-dimensional (3D) tubular molybdenum disulfide (MoS2) as both an active material in electrochemical reaction and a framework to provide more paths for insertion and extraction of ions, PANI nanowire arrays with a diameter of 10-20 nm can be controllably grown on both the external and internal surface of 3D tubular MoS2 by in situ oxidative polymerization of aniline monomers and 3D tubular MoS2/PANI hybrid materials with different amounts of PANI are prepared. A controllable growth of PANI nanowire arrays on the tubular MoS2 surface provides an opportunity to optimize the capacitive performance of the obtained electrodes. When the loading amount of PANI is 60%, the obtained MoS2/PANI-60 hybrid electrode not only shows a high specific capacitance of 552 F/g at a current density of 0.5 A/g, but also gives excellent rate capability of 82% from 0.5 to 30 A/g. The remarkable rate performance can be mainly attributed to the architecture with synergistic effect between 3D tubular MoS2 and PANI nanowire arrays. Moreover, the MoS2/PANI-60 based symmetric supercapacitor also exhibits the excellent rate performance and good cycling stability. The specific capacitance based on the total mass of the two electrodes is 124 F/g at a current density of 1 A/g and 79% of its initial capacitance is remained after 6000 cycles. The 3D tubular structure provides a good and favorable method for improving the capacitance retention of PANI electrode. PMID:26645314

  12. Monitoring changes in physical performance with heart rate measures in young soccer players.

    PubMed

    Buchheit, M; Simpson, M B; Al Haddad, H; Bourdon, P C; Mendez-Villanueva, A

    2012-02-01

    The aim of the present study was to verify the validity of using exercise heart rate (HRex), HR recovery (HRR) and post-exercise HR variability (HRV) during and after a submaximal running test to predict changes in physical performance over an entire competitive season in highly trained young soccer players. Sixty-five complete data sets were analyzed comparing two consecutive testing sessions (3-4 months apart) collected on 46 players (age 15.1 ± 1.5 years). Physical performance tests included a 5-min run at 9 km h(-1) followed by a seated 5-min recovery period to measure HRex, HRR and HRV, a counter movement jump, acceleration and maximal sprinting speed obtained during a 40-m sprint with 10-m splits, repeated-sprint performance and an incremental running test to estimate maximal cardiorespiratory function (end test velocity V (Vam-Eval)). Possible changes in physical performance were examined for the players presenting a substantial change in HR measures over two consecutive testing sessions (greater than 3, 13 and 10% for HRex, HRR and HRV, respectively). A decrease in HRex or increase in HRV was associated with likely improvements in V (Vam-Eval); opposite changes led to unclear changes in V (Vam-Eval). Moderate relationships were also found between individual changes in HRR and sprint [r = 0.39, 90% CL (0.07;0.64)] and repeated-sprint performance [r = -0.38 (-0.05;-0.64)]. To conclude, while monitoring HRex and HRV was effective in tracking improvements in V (Vam-Eval), changes in HRR were moderately associated with changes in (repeated-)sprint performance. The present data also question the use of HRex and HRV as systematic markers of physical performance decrements in youth soccer players. PMID:21656232

  13. Success rates and prognosis of heart valvuloplasty and valve replacement performed for elderly patients

    PubMed Central

    Liu, Weichao; He, Fei; Shi, Gongning

    2015-01-01

    Objective: To analyze the success rates and prognosis of heart valvuloplasty and valve replacement for elderly patients, and to provide clinical evidence. Methods: A total of 1240 patients who received heart valve surgeries in our hospital from June 2004 to October 2014 were selected and retrospectively analyzed. They were divided into two groups based on age (60), and those older than 60 (Group B) suffered from rheumatic valvular heart disease and nonrheumatic valvular heart disease including degenerative valve disease. Mitral valve replacement (MVR), tricuspid valve replacement (TVR), aortic valve replacement (AVR), double valve replacement (DVR), mitral valvuloplasty (MVP) and tricuspid valvuloplasty (TVP) were performed by using bioprosthetic and mechanical valves. Before surgery, coronary angiography, coronary artery bypass grafting (CABG), left atrial thrombectomy, left atrial wall folding and radiofrequency ablation were conducted. For the patients younger than 60 (Group A) who had congenital heart disease, rheumatic valvular heart disease and valvular heart disease, MVR, AVR, DVR, MVP, TVP and closed cuspid commissurotomy were performed with bioprosthetic and mechanical valves. The two groups were then monitored. Results: The mortality rates of Group A and Group B were 2.7% (16 cases) and 3.1% (20 cases) respectively. They died mainly of malignant ventricular arrhythmias, multiple organ failure, left ventricular rupture, low cardiac output syndrome, acute renal failure, respiratory failure, upper gastrointestinal bleeding, mechanical valve failure and cerebrovascular accident. The two groups had significantly different application rates of bioprosthetic valve, times of auxiliary ventilation and hospitalization stay lengths (P<0.05), but left ventricular ejection fractions, left ventricular end-diastolic diameters (LVEDDs), mortality rates as well as times of aortic cross-clamping and cardiopulmonary bypass were similar (P>0.05). LVEDD, complicated coronary

  14. Relationships between metabolic rate, muscle electromyograms, and swim performance of adult chinook salmon

    SciTech Connect

    Geist, David R. ); Brown, Richard S. ); Cullinan, Valerie I. ); Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A. )

    2003-10-01

    We measured oxygen consumption rates of adult spring Chinook salmon and compared these values to other species of Pacific salmon. Our results indicated that adult salmon achieve their maximum level of oxygen consumption at about their upper critical swim speed. It is also at this speed that the majority of the energy supplied to the swimming fish switches from red muscle (powered by aerobic metabolism) to white muscle (powered by anaerobic metabolism). Determining the swimming performance of adult salmon will assist managers in developing fishways and other means to safely pass fish over hydroelectric dams and other man-made structures.

  15. Performance and Abuse Testing of 5 Year Old Low Rate and Medium Rate Lithium Thionyl Chloride Cells

    NASA Technical Reports Server (NTRS)

    Frerker, Rick; Zhang, Wenlin; Jeevarajan, Judith; Bragg, Bobby J.

    2001-01-01

    Most cells survived the 3 amp (A) over-discharge at room temperature for 2 hours. The cell that failed was the LTC-114 after high rate discharge of 500 mA similar to the results of the 1 A over-discharge test. Most cells opened during 0.05 Ohm short circuit test without incident but three LTC-111 cells exploded apparently due to a lack of a thermal cutoff switch. The LTC-114 cells exposed to a hard short of 0.05 Ohms recovered but the LTC-114 cells exposed to a soft short of 1 Ohm did not. This is probably due to the activation of a resetable fuse during a hard short. Fresh cells tend to survive exposure to higher temperatures than cells previously discharged at high rate (1 Amp). LTC-111 cells tend to vent at lower temperatures than the all LTC-114 cells and the LTC-115 cells that were previously discharged at rates exceeding 1 Amp.

  16. Feasibility of Amorphous Selenium Based Photon Counting Detectors for Digital Breast Tomosynthesis

    SciTech Connect

    Chen, J.; O'Connor, P.; Lehnert, J., De Geronimo, G., Dolazza, E., Tousignant, O., Laperriere, L., Greenspan, J., Zhao, W.

    2009-02-27

    Amorphous selenium (a-Se) has been incorporated successfully in direct conversion flat panel x-ray detectors, and has demonstrated superior image quality in screening mammography and digital breast tomosynthesis (DBT) under energy integration mode. The present work explores the potential of a-Se for photon counting detectors in DBT. We investigated major factors contributing to the variation in the charge collected by a pixel upon absorption of each x-ray photon. These factors included x-ray photon interaction, detector geometry, charge transport, and the pulse shaping and noise properties of the photon counting readout circuit. Experimental measurements were performed on a linear array test structure constructed by evaporating an a-Se layer onto an array of 100 {mu}m pitch strip electrodes, which are connected to a 32 channel low noise photon counting integrated circuit. The measured pulse height spectrum (PHS) under polychromatic xray exposure was interpreted quantitatively using the factors identified. Based on the understanding of a-Se photon counting performance, design parameters were proposed for a 2D detector with high quantum efficiency and count rate that could meet the requirements of photon counting detector for DBT.

  17. Supplemental selenium source in Holstein steers challenged with intranasal bovine infectious rhinotracheitis virus and in newly received beef heifers: Performance, morbidity, antibody titers, and blood cell counts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Viral infection in newly received feedlot cattle can lead to oxidative stress. As a constituent of glutathione peroxidase (GSH-Px), Se plays a vital antioxidant role. Our objective was to evaluate effects of Se source on performance and health of calves challenged with infectious bovine rhinotrachei...

  18. Characterizing shallow secondary clarifier performance where conventional flux theory over-estimates allowable solids loading rate.

    PubMed

    Daigger, Glen T; Siczka, John S; Smith, Thomas F; Frank, David A; McCorquodale, J A

    2016-01-01

    The performance characteristics of relatively shallow (3.3 and 3.7 m sidewater depth in 30.5 m diameter) activated sludge secondary clarifiers were extensively evaluated during a 2-year testing program at the City of Akron Water Reclamation Facility (WRF), Ohio, USA. Testing included hydraulic and solids loading stress tests, and measurement of sludge characteristics (zone settling velocity (ZSV), dispersed and flocculated total suspended solids), and the results were used to calibrate computational fluid dynamic (CFD) models of the various clarifiers tested. The results demonstrated that good performance could be sustained at surface overflow rates in excess of 3 m/h, as long as the clarifier influent mixed liquor suspended solids (MLSS) concentration was controlled to below critical values. The limiting solids loading rate (SLR) was significantly lower than the value predicted by conventional solids flux analysis based on the measured ZSV/MLSS relationship. CFD analysis suggested that this resulted because mixed liquor entering the clarifier was being directed into the settled sludge blanket, diluting it and also creating a 'thin' concentration sludge blanket that overlays the thicker concentration sludge blanket typically expected. These results indicate the need to determine the allowable SLR for shallow clarifiers using approaches other than traditional solids flux analysis. A combination of actual testing and CFD analyses are demonstrated here to be effective in doing so. PMID:27438236

  19. Augmenting data rate performance for higher order modulation in triangular index profile multicore fiber interconnect

    NASA Astrophysics Data System (ADS)

    Mishra, Jitendra K.; Priye, Vishnu; Rahman, B. M. A.

    2016-07-01

    A triangular profile multicore fiber (MCF) optical interconnect (OI) is investigated to augment performance that typically degrades at high data rates for higher order modulation in a short reach transmission system. Firstly, probability density functions (PDFs) variation with inter-core crosstalk is calculated for 8-core MCF OI with different index profile in the core and it was observed that the triangular profile MCF OI is the most crosstalk tolerant. Next, symbol error probability (SEP) for higher order quadrature phase shift keying (QPSK) modulated signal due to inter-core crosstalk is analytically obtained and their dependence on typical characteristic parameters are examined. Further, numerical simulations are carried out to compare the error performance of QPSK for step index and triangular index MCF OI by generating eye diagram at 40 Gbps per channel. Finally, it is shown that MCF OI with triangular index profile supporting QPSK has double spectral efficiency with tolerable trade off in SEP as compared with those of binary phase shift keying (BPSK) at high data rates which is scalable up to 5 Tbps.

  20. Microporous organic polymer-based lithium ion batteries with improved rate performance and energy density

    NASA Astrophysics Data System (ADS)

    Zhang, Chong; Yang, Xiao; Ren, Wenfeng; Wang, Yanhong; Su, Fabing; Jiang, Jia-Xing

    2016-06-01

    Microporous organic polymers with triphenylamine segments were employed as cathode materials for lithium ion batteries. YPTPA with the highest surface area exhibits a discharge plateau at ∼3.6 V vs. Li/Li+, an initial Coulombic efficiency of 96.8% at 50 mA g-1 and a discharge capacity of 105.7 mAh g-1 at 200 mA g-1. Compared to the homo-coupled polymer of OPTPA with relatively low surface area (66 m2 g-1), SPTPA and YPTPA with higher surface area (544 and 1557 m2 g-1, respectively) show enhanced rate performances and energy densities. YPTPA can deliver 97.6 mAh g-1 within less than 3 min at high rate of 2000 mA g-1 and the energy density of 334 Wh kg-1 under an ultrahigh power density of 6816 W kg-1, while OPTPA only presents 48.2 mAh g-1 at 2000 mA g-1 with an energy density of 155 Wh kg-1 under 6414 W kg-1. The great improvement in electrochemical properties of SPTPA and YPTPA demonstrates that increasing surface area of polymer cathodes by interweaving the redox-active units into microporous polymer skeleton is an efficient way to develop advanced polymer cathode materials with outstanding electrochemical performance.

  1. Reducing job insecurity and increasing performance ratings: does impression management matter?

    PubMed

    Huang, Guo-hua; Zhao, Helen Hailin; Niu, Xiong-ying; Ashford, Susan J; Lee, Cynthia

    2013-09-01

    Prior research on job insecurity has demonstrated its detrimental effects on both employees and the organization, yet no research has detailed how people actively deal with it. Drawing from proactivity research, this article argues that job insecurity prompts a proactive use of impression management tactics in the workplace. The effectiveness of these tactics depends on the level of supervisory liking for the employee and the attributions supervisors make regarding the employee's motives for the impression management behaviors (i.e., for the good of the organization or for self-interest). A 3-wave survey study of 271 Chinese employees and their supervisors showed that employees experiencing job insecurity in Time 1 reported using a variety of tactics to impress their supervisors at Time 2 and that these tactics curbed the affect associated with job insecurity and enhanced supervisor rated performance, through supervisor's liking and attributed motives. The relationship between impression management and increased supervisor-rated performance was moderated by supervisor attributions; the relationship between impression management and reduced affective job insecurity depended on supervisor liking. PMID:23731028

  2. Performance of two-stage vegetable waste anaerobic digestion depending on varying recirculation rates.

    PubMed

    Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

    2014-06-01

    Vegetable waste, which characterized by high moisture content, was evaluated as a substrate for biogas production. The effects of recirculation rate (RR) on the performance of two-stage anaerobic digestion were investigated. The system was operated at an organic loading rate of 1.7 g VS/L/d with varying RRs (0, 0.6, 1, and 1.4). Results demonstrated that volumetric biogas production rates in acidogenic reactor increased from approximately 0.2 7 L/L/d to 0.97 L/L/d, when pH is increased from approximately 5.1 to 6.7. These indicate that recirculation of alkaline effluent from the methanogenic reactor helps create a favorable condition for biogas production in the acidogenic reactor. The decrease in chemical oxygen demand (COD) concentrations from approximately 21,000 mg/L to 6800 mg/L was also observed in the acidogenic reactor. This condition may be attributed to dilution under recirculation. The dynamics between hydrolysis and methanogenesis under recirculation indicated that mass transfer capacity between two-stage reactors improved. PMID:24759642

  3. High-performance, high-chip-count optical code division multiple access encoders-decoders based on a reconstruction equivalent-chirp technique.

    PubMed

    Dai, Yitang; Chen, Xiangfei; Sun, Jie; Yao, Yu; Xie, Shizhong

    2006-06-01

    Fiber Bragg grating-based, 511 chip, 500 Gchip/s encoders-decoders are experimentally demonstrated by the reconstruction equivalent-chirp (REC) method. Encoding-decoding efficiency close to the theoretical value is achieved. Without any real phase shifts, the encoders-decoders are fabricated by use of the traditional setup. Highly precise phase control requires only submicrometer precision. The encoding-decoding performance can be further improved by REC-based correction. PMID:16688239

  4. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise

    PubMed Central

    Killen, Shaun S.; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise

  5. High-Intensity Intermittent Exercise and its Effects on Heart Rate Variability and Subsequent Strength Performance

    PubMed Central

    Panissa, Valéria L. G.; Cal Abad, Cesar C.; Julio, Ursula F.; Andreato, Leonardo V.; Franchini, Emerson

    2016-01-01

    Prupose: To investigate the effects of a 5-km high-intensity interval exercise (HIIE) on heart rate variability (HRV) and subsequent strength performance. Methods: Nine trained males performed a control session composed of a half-squat strength exercise (4 × 80% of one repetition maximum—1 RM) in isolation and 30-min, 1-, 4-, 8-, and 24-h after an HIIE (1-min at the velocity peak:1-min passive recovery). All experimental sessions were performed on different days. The maximum number of repetitions (MNR) and total weight lifted (TWL) during the strength exercise were registered in all conditions; in addition, prior to each session, HRV were assessed [beat-to-beat intervals (RR) and log-transformed of root means square of successive differences in the normal-to-normal intervals (lnRMSSD)]. Results: Performance in the strength exercise dropped at 30-min (31%) and 1-h (19%) post-HIIE concomitantly with lower values of RR (781 ± 79 ms; 799 ± 134 ms, respectively) in the same recovery intervals compared to the control (1015 ± 197 ms). Inferential analysis did not detect any effect of condition on lnRMSSD, however, values were lower after 30-min (3.5 ± 0.4 ms) and 1-h (3.3 ± 0.5 ms) with moderate and large effect sizes (0.9 and 1.2, respectively) compared with the control condition (3.9 ± 0.4 ms). Conclusion: Both RR and lnRMSSD seem to be associated with deleterious effects on strength performance, although further studies should be conducted to clarify this association. PMID:26973543

  6. Factors affecting leukocyte count in healthy adults.

    PubMed

    Carel, R S; Eviatar, J

    1985-09-01

    The relationships between white blood cell (WBC) count, smoking, and other health variables were determined among 35,000 apparently healthy men and women. The effect of smoking on the WBC count was greater than that of all other variables. The leukocyte level and the variance in WBC count values increased with increased smoking intensity. The relationship between smoking intensity and leukocyte level is expressed quantitatively by the following regression equation: WBC (10(3)/mm3) = 7.1 + 0.05(SM), where SM has seven values according to the smoking level. Multiple regression analysis with additional variables other than smoking did not much improve the predictive value of the equation. The effect of smoking on WBC count could be only partially explained by an inflammatory process, e.g., chronic bronchitis. Relationships of statistical significance (but mostly with r values of less than 0.10) were found between WBC count and the following variables: hemoglobin, heart rate, weight (or Quetelet index), cholesterol, uric acid, creatinine, sex, ethnic origin, systolic blood pressure, height, blood sugar, and diastolic blood pressure. The normal WBC count range for smokers differs from that of nonsmokers and is shifted to the right according to the smoking level. This may have both a diagnostic and prognostic significance in different clinical settings. PMID:4070192

  7. Using Student and Institutional Characteristics to Predict Graduation Rates at Community Colleges: New Developments in Performance Measures and Institutional Effectiveness

    ERIC Educational Resources Information Center

    Moosai, Susan; Walker, David A.; Floyd, Deborah L.

    2011-01-01

    Prediction models using graduation rate as the performance indicator were obtained for community colleges in California, Florida, and Michigan. The results of this study indicated that institutional graduation rate could be predicted effectively from an aggregate of student and institutional characteristics. A performance measure was computed, the…

  8. Error Rates in Measuring Teacher and School Performance Based on Student Test Score Gains. NCEE 2010-4004

    ERIC Educational Resources Information Center

    Schochet, Peter Z.; Chiang, Hanley S.

    2010-01-01

    This paper addresses likely error rates for measuring teacher and school performance in the upper elementary grades using value-added models applied to student test score gain data. Using realistic performance measurement system schemes based on hypothesis testing, we develop error rate formulas based on OLS and Empirical Bayes estimators.…

  9. Design Study of an Incinerator Ash Conveyor Counting System - 13323

    SciTech Connect

    Jaederstroem, Henrik; Bronson, Frazier

    2013-07-01

    A design study has been performed for a system that should measure the Cs-137 activity in ash from an incinerator. Radioactive ash, expected to consist of both Cs-134 and Cs-137, will be transported on a conveyor belt at 0.1 m/s. The objective of the counting system is to determine the Cs-137 activity and direct the ash to the correct stream after a diverter. The decision levels are ranging from 8000 to 400000 Bq/kg and the decision error should be as low as possible. The decision error depends on the total measurement uncertainty which depends on the counting statistics and the uncertainty in the efficiency of the geometry. For the low activity decision it is necessary to know the efficiency to be able to determine if the signal from the Cs-137 is above the minimum detectable activity and that it generates enough counts to reach the desired precision. For the higher activity decision the uncertainty of the efficiency needs to be understood to minimize decision errors. The total efficiency of the detector is needed to be able to determine if the detector will be able operate at the count rate at the highest expected activity. The design study that is presented in this paper describes how the objectives of the monitoring systems were obtained, the choice of detector was made and how ISOCS (In Situ Object Counting System) mathematical modeling was used to calculate the efficiency. The ISOCS uncertainty estimator (IUE) was used to determine which parameters of the ash was important to know accurately in order to minimize the uncertainty of the efficiency. The examined parameters include the height of the ash on the conveyor belt, the matrix composition and density and relative efficiency of the detector. (authors)

  10. Evaluation of the Performance of the PVUSA Rating Methodology Applied to Dual Junction PV Technology: Preprint (Revised)

    SciTech Connect

    Myers, D. R.

    2009-07-01

    The PVUSA (Photovoltaics for Utility Scale Applications) project in the 1990's developed a rating methodology for PV performance evaluation which has become popular, and even incorporated into concentrating PV rating standards This report apply that method to rack-mounted dual-junction PV system, and produces a system rating.

  11. Dose rate dependence of the current noise performance of an ultra-low noise precision bipolar operational amplifier

    SciTech Connect

    Hiemstra, D.M.

    1999-12-01

    The dose rate dependence of the current noise of a bipolar operational amplifier is presented. Total current noise performance degrades linearly with increasing dose rate. Generation-recombination, white and 1/f spectral components contribute to the degradation. The generation-recombination component is the most significant contributor to dose rate dependent current noise degradation.

  12. The Effects of Guided Imagery on Heart Rate Variability in Simulated Spaceflight Emergency Tasks Performers

    PubMed Central

    Yijing, Zhang; Xiaoping, Du; Fang, Liu; Xiaolu, Jing; Bin, Wu

    2015-01-01

    Objectives. The present study aimed to investigate the effects of guided imagery training on heart rate variability in individuals while performing spaceflight emergency tasks. Materials and Methods. Twenty-one student subjects were recruited for the experiment and randomly divided into two groups: imagery group (n = 11) and control group (n = 10). The imagery group received instructor-guided imagery (session 1) and self-guided imagery training (session 2) consecutively, while the control group only received conventional training. Electrocardiograms of the subjects were recorded during their performance of nine spaceflight emergency tasks after imagery training. Results. In both of the sessions, the root mean square of successive differences (RMSSD), the standard deviation of all normal NN (SDNN), the proportion of NN50 divided by the total number of NNs (PNN50), the very low frequency (VLF), the low frequency (LF), the high frequency (HF), and the total power (TP) in the imagery group were significantly higher than those in the control group. Moreover, LF/HF of the subjects after instructor-guided imagery training was lower than that after self-guided imagery training. Conclusions. Guided imagery was an effective regulator for HRV indices and could be a potential stress countermeasure in performing spaceflight tasks. PMID:26137491

  13. Effects of sampling strategy, detection probability, and independence of counts on the use of point counts

    USGS Publications Warehouse

    Pendleton, G.W.

    1995-01-01

    Many factors affect the use of point counts for monitoring bird populations, including sampling strategies, variation in detection rates, and independence of sample points. The most commonly used sampling plans are stratified sampling, cluster sampling, and systematic sampling. Each of these might be most useful for different objectives or field situations. Variation in detection probabilities and lack of independence among sample points can bias estimates and measures of precision. All of these factors should be con-sidered when using point count methods.

  14. Effects of Time-Release Caffeine Containing Supplement on Metabolic Rate, Glycerol Concentration and Performance

    PubMed Central

    Gonzalez, Adam M.; Hoffman, Jay R.; Wells, Adam J.; Mangine, Gerald T.; Townsend, Jeremy R.; Jajtner, Adam R.; Wang, Ran; Miramonti, Amelia A.; Pruna, Gabriel J.; LaMonica, Michael B.; Bohner, Jonathan D.; Hoffman, Mattan W.; Oliveira, Leonardo P.; Fukuda, David H.; Fragala, Maren S.; Stout, Jeffrey R.

    2015-01-01

    This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF) versus a regular caffeine capsule (CAF) and a placebo (PL). Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y) who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05) in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042) in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86) or metabolic measures (p = 0.17-0.91). Physical reaction time was significantly improved for CAF at hour 5 (p=0.01) compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively) and over the 8-hour period (p = 0.04 and p = 0.001, respectively) compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004). TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures. Key points Time-release caffeine and regular caffeine showed distinct pharmacokinetics over an 8-hour period following ingestion. Time-release caffeine and regular caffeine yielded modest effects on reaction time over an 8-hour period following ingestion. Time-release caffeine and regular caffeine did not alter glycerol concentration, metabolic measures, or other performance measures over an 8-hour period following ingestion. PMID:25983581

  15. Evaluation of Pulse Counting for the Mars Organic Mass Analyzer (MOMA) Ion Trap Detection Scheme

    NASA Technical Reports Server (NTRS)

    Van Amerom, Friso H.; Short, Tim; Brinckerhoff, William; Mahaffy, Paul; Kleyner, Igor; Cotter, Robert J.; Pinnick, Veronica; Hoffman, Lars; Danell, Ryan M.; Lyness, Eric I.

    2011-01-01

    The Mars Organic Mass Analyzer is being developed at Goddard Space Flight Center to identify organics and possible biological compounds on Mars. In the process of characterizing mass spectrometer size, weight, and power consumption, the use of pulse counting was considered for ion detection. Pulse counting has advantages over analog-mode amplification of the electron multiplier signal. Some advantages are reduced size of electronic components, low power consumption, ability to remotely characterize detector performance, and avoidance of analog circuit noise. The use of pulse counting as a detection method with ion trap instruments is relatively rare. However, with the recent development of high performance electrical components, this detection method is quite suitable and can demonstrate significant advantages over analog methods. Methods A prototype quadrupole ion trap mass spectrometer with an internal electron ionization source was used as a test setup to develop and evaluate the pulse-counting method. The anode signal from the electron multiplier was preamplified. The an1plified signal was fed into a fast comparator for pulse-level discrimination. The output of the comparator was fed directly into a Xilinx FPGA development board. Verilog HDL software was written to bin the counts at user-selectable intervals. This system was able to count pulses at rates in the GHz range. The stored ion count nun1ber per bin was transferred to custom ion trap control software. Pulse-counting mass spectra were compared with mass spectra obtained using the standard analog-mode ion detection. Prelin1inary Data Preliminary mass spectra have been obtained for both analog mode and pulse-counting mode under several sets of instrument operating conditions. Comparison of the spectra revealed better peak shapes for pulse-counting mode. Noise levels are as good as, or better than, analog-mode detection noise levels. To artificially force ion pile-up conditions, the ion trap was overfilled

  16. Optimal gate-width setting for passive neutrons multiplicity counting

    SciTech Connect

    Croft, Stephen; Evans, Louise G; Schear, Melissa A

    2010-01-01

    When setting up a passive neutron coincidence counter it is natural to ask what coincidence gate settings should be used to optimize the counting precision. If the gate width is too short then signal is lost and the precision is compromised because in a given period only a few coincidence events will be observed. On the other hand if the gate is too large the signal will be maximized but it will also be compromised by the high level of random pile-up or Accidental coincidence events which must be subtracted. In the case of shift register electronics connected to an assay chamber with an exponential dieaway profile operating in the regime where the Accidentals rate dominates the Reals coincidence rate but where dead-time is not a concern, simple arguments allow one to show that the relative precision on the net Reals rate is minimized when the coincidence gate is set to about 1.2 times the lie dieaway time of the system. In this work we show that making the same assumptions it is easy to show that the relative precision on the Triples rates is also at a minimum when the relative precision of the Doubles (or Reals) is at a minimum. Although the analysis is straightforward to our knowledge such a discussion has not been documented in the literature before. Actual measurement systems do not always behave in the ideal we choose to model them. Fortunately however the variation in the relative precision as a function of gate width is rather flat for traditional safeguards counters and so the performance is somewhat forgiving of the exact choice. The derivation further serves to delineate the important parameters which determine the relative counting precision of the Doubles and Triples rates under the regime considered. To illustrate the similarities and differences we consider the relative standard deviation that might be anticipated for a passive correlation count of an axial section of a spent nuclear fuel assembly under practically achievable conditions.

  17. Critical transport rates that limit the performance of microbial electrochemistry technologies.

    PubMed

    Popat, Sudeep C; Torres, César I

    2016-09-01

    Microbial electrochemistry technologies (METs) take advantage of the connection of microorganisms with electrodes. In the classic case of a microbial anode, the maximization of current density produced is often the goal. But, current production is dependent on many transport processes occurring, which can be rate-limiting. These include the fluxes of electron donor and acceptor, the ionic flux, the acidity and alkalinity fluxes at anode and cathode respectively, the electron transport flux at the biofilm, and the reactant/product crossover flux. Associated with these fluxes are inherent concentration gradients that can affect performance. This critical review provides an analysis on how these transport processes have hindered the development of METs, and how MET designs have evolved as more knowledge of these transport limitations is gained. Finally, suggestions are provided on how to design MET systems taking into consideration critical transport processes that are intimately linked to the current produced. PMID:27211921

  18. The effect of Be and Cr electrode deposition rate on the performance of MIS solar cells

    NASA Astrophysics Data System (ADS)

    Moharram, A. H.; Panayotatos, P.; Yeh, J. L.; Lalevic, B.

    1985-07-01

    An experimental study has been performed on MIS solar cells with Be, Cr and layered Cr-Be electrodes on single crystal Si, Wacker and Monsanto poly-Si substrates. Electrical characterization in the dark and under illumination was correlated to X-ray and Auger spectroscopy results. It was found that the electrode deposition rate directly affects the oxygen content of the electrodes for all metal-substrate configurations. This oxygen is believed to originate from the deposition ambient as well as from the SiO2 layer. In the case of cells with Cr and layered Cr-Be electrodes oxygen acts to reduce the electrode work function (thus increasing the open-circuit voltage) in direct proportion to the relative content of oxygen to chromium.

  19. The performance and reliability of wavelet denoising for Doppler ultrasound fetal heart rate signal preprocessing.

    PubMed

    Papadimitriou, S; Papadopoulos, V; Gatzounas, D; Tzigounis, V; Bezerianos, A

    1997-01-01

    The present paper deals with the performance and the reliability of a Wavelet Denoising method for Doppler ultrasound Fetal Heart Rate (FHR) recordings. It displays strong evidence that the denoising process extracts the actual noise components. The analysis is approached with three methods. First, the power spectrum of the denoised FHR displays more clearly an 1/fa scaling law, i.e. the characteristic of fractal time series. Second, the rescaled scale analysis technique reveals a Hurst exponent at the range of 0.7-0.8 that corresponds to a long memory persistent process. Moreover, the variance of the Hurst exponent across time scales is smaller at the denoised signal. Third, a chaotic attractor reconstructed with the embedding dimension technique becomes evident at the denoised signals, while it is completely obscured at the unfiltered ones. PMID:10179728

  20. Growth Curve Models for Zero-Inflated Count Data: An Application to Smoking Behavior

    ERIC Educational Resources Information Center

    Liu, Hui; Powers, Daniel A.

    2007-01-01

    This article applies growth curve models to longitudinal count data characterized by an excess of zero counts. We discuss a zero-inflated Poisson regression model for longitudinal data in which the impact of covariates on the initial counts and the rate of change in counts over time is the focus of inference. Basic growth curve models using a…

  1. Stability of prepared iodine counting standards

    SciTech Connect

    McLain, M.E.; Yoon, S.C. )

    1987-05-01

    This paper reports that the uses for iodine-125 in the medical sciences are increasing. I-125 is often used to label organic molecules in the performance of radioimmunoassay (RIA) procedures, and it has recently been used in the form of 800-mCi sealed sources employed by bone mineral (density) analyzers in the diagnosis of osteoporosis. These applications of the 59.9-day half-life I-125 incur the need to perform contamination surveys. In the case of the use of I-125 labeled compounds, laboratory benches and floors must be regularly checked for the presence of contamination by counting smear or wipe samples. Where multimillicurie sealed I-125 sources are employed, leak tests must be performed, again by counting smear or wipe samples. The most sensitive method readily available for the measurement of I-125 on these smear samples is scintillation counting with a thin NaI(Tl) detector. The counting system used must be calibrated for I-125 counting efficiency.

  2. Contribution of hand motor circuits to counting.

    PubMed

    Andres, Michael; Seron, Xavier; Olivier, Etienne

    2007-04-01

    The finding that number processing activates a cortical network partly overlapping that recruited for hand movements has renewed interest in the relationship between number and finger representations. Further evidence about a possible link between fingers and numbers comes from developmental studies showing that finger movements play a crucial role in learning counting. However, increased activity in hand motor circuits during counting may unveil unspecific processes, such as shifting attention, reciting number names, or matching items with a number name. To address this issue, we used transcranial magnetic stimulation to measure changes in corticospinal (CS) excitability during a counting task performed silently and using either numbers or letters of the alphabet to enumerate items. We found an increased CS excitability of hand muscles during the counting task, irrespective of the use of numbers or letters, whereas it was unchanged in arm and foot muscles. Control tasks allowed us to rule out a possible influence of attention allocation or covert speech on CS excitability increase of hand muscles during counting. The present results support a specific involvement of hand motor circuits in counting because no CS changes were found in arm and foot muscles during the same task. However, the contribution of hand motor areas is not exclusively related to number processing because an increase in CS excitability was also found when letters were used to enumerate items. This finding suggests that hand motor circuits are involved whenever items have to be put in correspondence with the elements of any ordered series. PMID:17381248

  3. High rep rate high performance plasma focus as a powerful radiation source

    SciTech Connect

    Lee, S.; Lee, P.; Zhang, G.; Feng, X.; Liu, M.; Serban, A.; Wong, T.K.S.; Gribkov, V.A.

    1998-08-01

    Basic operational characteristics of the plasma focus are considered from design perspectives to develop powerful radiation sources. Using these ideas the authors have developed two compact plasma focus (CPF) devices operating in neon with high performance and high repetition rate capacity for use as an intense soft X-ray (SXR) source for microelectronics lithography. The NX1 is a four-module system with a peak current of 320 kA when the capacitor bank (7.8 {micro}F {times} 4) is charged to 14 kV. It produces 100 J of SXR per shot (4% wall plug efficiency) giving at 3 Hz, 300 W of average SXR power into 4{pi}. The NX2 is also a four-module system. Each module uses a rail gap switching 12 capacitors each with a capacity of 0.6 {micro}F. The NX2 operates with peak currents of 400 kA at 11.5 kV into water-cooled electrodes at repetition rates up to 16 Hz to produce 300 W SXR in burst durations of several minutes. SXR lithographs are taken from both machines to demonstrate that sufficient SXR lithographs are taken from both machines to demonstrate that sufficient SXR flux is generated for an exposure with only 300 shots. In addition, flash electron lithographs are also obtained requiring only ten shots per exposure. Such high performance compact machines may be improved to yield over 1 kW of SXR, enabling sufficient exposure throughput to be of interest to the wafer industry. In deuterium the neutron yield could be over 10{sup 10} neutrons per second over prolonged bursts of minutes.

  4. Dispersion and treatment performance analysis of an UASB reactor under different hydraulic loading rates.

    PubMed

    Peña, M R; Mara, D D; Avella, G P

    2006-02-01

    Mixing and transport phenomena affect the efficiency of all bioreactor configurations. An even mixing pattern at the macro-level is desirable to provide good conditions for substrate transport to, and from, the microbial aggregates. The state of segregation of particulate material in the reactor is also important. The production of biogas in anaerobic reactors is another factor that affects mixing intensity and hence the interactions between the liquid, solid and gaseous phases. The CSTR model with some degree of short-circuiting, dead zones and bypassing flows seems to describe the overall hydrodynamics of UASBs. However, few data are available in the literature for full-scale reactors that relate process performance to mixing characteristics. Dispersion studies using LiCl were done for four hydraulic loading rates on a full-scale UASB treating domestic wastewater in Ginebra, Valle del Cauca, southwest Colombia. COD, TSS, and Settleable Solids were used to evaluate the performance of organic matter removal. The UASB showed a complete mixing pattern for hydraulic loading rates close to the design value (i.e. Q = 10-13l s(-1) and HRT=8-6 h). Gross mixing distortions and localised stagnant zones, short-circuiting and bypass flows were found in the sludge bed and blanket zones for both extreme conditions (underloading and overloading). The liquid volume contained below the gas-liquid-solid separator was found to contribute to the overall stagnant volume, particularly when the reactor was underloaded. The removal of organic matter showed a log-linear correlation with the dispersion number. PMID:16405944

  5. Pack hike test finishing time for Australian firefighters: pass rates and correlates of performance.

    PubMed

    Phillips, M; Petersen, A; Abbiss, C R; Netto, K; Payne, W; Nichols, D; Aisbett, B

    2011-03-01

    The pack hike test (PHT, 4.83 km hike wearing a 20.4-kg load) was devised to determine the job readiness of USA wildland firefighters. This study measured PHT performance in a sample of Australian firefighters who currently perform the PHT (career land management firefighters, LMFF) and those who do not (suburban/regional volunteer firefighters, VFF). The study also investigated the relationships between firefighters' PHT performance and their performance across a range of fitness tests for both groups. Twenty LMFF and eighteen age-, body mass-, and height-matched VFF attempted the PHT, and a series of muscular endurance, power, strength and cardiorespiratory fitness tests. Bivariate correlations between the participants' PHT finishing time and their performance in a suite of different fitness tests were determined using Pearson's product moment correlation coefficient. The mean PHT finishing time for LMFF (42.2 ± 2.8 min) was 9 ± 14% faster (p = 0.001) than for VFF (46.1 ± 3.6 min). The pass rate (the percentage of participants who completed the PHT in under 45 min) for LMFF (90%) was greater than that of VFF (39%, p = 0.001). For LMFF, VO(2peak) in L min(-1)(r = -0.66, p = 0.001) and the duration they could sustain a grip 'force' of 25 kg (r = -0.69, p = 0.001) were strongly correlated with PHT finishing time. For VFF, VO(2peak) in mL kg(-1) min(-1)(r = -0.75, p = 0.002) and the duration they could hold a 1.2-m bar attached to 45.5 kg in a 'hose spray position' (r = -0.69, p = 0.004) were strongly correlated with PHT finishing time. This study shows that PHT fitness-screening could severely limit the number of VFF eligible for duty, compromising workforce numbers and highlights the need for specific and valid firefighter fitness standards. The results also demonstrate the strong relationships between PHT performance and firefighters' cardiorespiratory fitness and local muscular endurance. Those preparing for the PHT should focus their training on these fitness

  6. Seasonal changes in physical performance and heart rate variability in high level futsal players.

    PubMed

    Oliveira, R S; Leicht, A S; Bishop, D; Barbero-Álvarez, J C; Nakamura, F Y

    2013-05-01

    The aim of this study was to determine the changes in physical performance and resting heart rate variability (HRV) in professional futsal players during the pre-season and in-season training periods. 11 athletes took part in the study (age=24.3±2.9 years; height=176.3±5.2 cm; weight=76.1±6.3 kg), and performed a repeated-sprint ability (RSA) test [6×40 m (20+20 m with a 180° change of direction) sprints separated by 20 s of passive recovery] and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) at 3 different moments (M1=beginning of pre-season; M2=end of pre-season; M3=mid in-season). The HRV indices were assessed at the same moments. After the short pre-season (3-week), mean RSA time (RSAmean) (M1=7.43±0.2 s; M2=7.24±0.2 s; P=0.003), decrement in RSA performance (RSAdecrement) (M1=6.7±0.3%; M2=5.0±0.9%; P=0.001), and Yo-Yo IR1 distance (M1=1.244±298 m; M2=1.491±396 m; P=0.002) were significantly improved (P<0.05). During the in-season (i. e., M3), performance in Yo-Yo IR1 and RSAmean were maintained. In contrast, RSAbest (M2=6.89±0.2 to M3=6.69±0.3; P=0.001) was improved and RSAdecrement (M2=5.0±0.9% to M3=6.6±0.9%; P=0.001) was impaired. At M2, there was an increase in HRV vagal-related indices compared with M1 that was maintained at M3. In conclusion, after a short pre-season, futsal players improved their RSA and Yo-Yo IR1 performance with concomitant improvements in HRV. These indices were maintained during the in-season period while RSAbest was improved and RSAdecrement impaired. Frequent monitoring of these performances and HRV indices may assist with identification of individual training adaptations and/or early signs of maladaption. PMID:23143705

  7. Relationships Between Metabolic Rate, Muscle Electromyograms and Swim Performance of Adult Chinook Salmon

    SciTech Connect

    Geist, David R.; Brown, Richard S.; Cullinan, Valerie I.; Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A.

    2003-10-01

    In 2000 Pacific Northwest National Laboratory initiated a two-year study to investigate the metabolic rate and swimming performance and to estimate the total energy used (i.e., aerobic and anaerobic) by adult spring Chinook salmon migrating upstream through a large hydropower dam on the Columbia River. The investigation involved one year of laboratory study and one year of field study at Bonneville Dam. The objectives of the laboratory study, reported here, were to (1) measure active rates of oxygen consumption of adult spring chinook salmon at three water temperatures over a range of swimming speeds; (2) estimate the Ucrit of adult spring chinook salmon; and (3) monitor EMGs of red and white muscle in the salmon over a range of swimming speeds. Future papers will report on the results of the field study. Our results indicated that the rate of oxygen consumption and red and white muscle activity in adult spring chinook salmon were strongly correlated with swimming speed over a range of fish sizes and at three different temperatures. Active oxygen consumption increased linearly with swim speed before leveling off at speeds at or above Ucrit. This pattern was similar at each water temperature and indicated that fish were approaching their maximal aerobic oxygen consumption at higher swim speeds. Modeling showed that temperature, but not size or sex, influenced the relation between V02 and swim speed, thus a V02-swim speed model based on temperature (but independent of sex and size) should be a biologically relevant way of estimating the energy use of fish in the wild.

  8. Engine Performance and Knock Rating of Fuels for High-output Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Rothbrock, A M; Biermann, Arnold E

    1938-01-01

    Data are presented to show the effects of inlet-air pressure, inlet-air temperature, and compression ratio on the maximum permissible performance obtained on a single-cylinder test engine with aircraft-engine fuels varying from a fuel of 87 octane number to one 100 octane number plus 1 ml of tetraethyl lead per gallon. The data were obtained on a 5-inch by 5.75-inch liquid-cooled engine operating at 2,500 r.p.m. The compression ratio was varied from 6.50 to 8.75. The inlet-air temperature was varied from 120 to 280 F. and the inlet-air pressure from 30 inches of mercury absolute to the highest permissible. The limiting factors for the increase in compression ratio and in inlet-air pressure was the occurrence of either audible or incipient knock. The data are correlated to show that, for any one fuel,there is a definite relationship between the limiting conditions of inlet-air temperature and density at any compression ratio. This relationship is dependent on the combustion-gas temperature and density relationship that causes knock. The report presents a suggested method of rating aircraft-engine fuels based on this relationship. It is concluded that aircraft-engine fuels cannot be satisfactorily rated by any single factor, such as octane number, highest useful compression ratio, or allowable boost pressure. The fuels should be rated by a curve that expresses the limitations of the fuel over a variety of engine conditions.

  9. Kids Count Report in Nebraska, 2002.

    ERIC Educational Resources Information Center

    Johnston, Janet M.

    This Kids Count report examines statewide trend data on the well-being of Nebraska's children. Section 1 of the report presents U.S. Census data on population trends in Nebraska as well as child poverty rates, and urges Nebraskans to work together to ensure that its youngest citizens have the best start possible. Section 2, the bulk of this…

  10. Technology Counts 2007: A Digital Decade

    ERIC Educational Resources Information Center

    Education Week, 2007

    2007-01-01

    "Technology Counts 2007" looks back, and ahead, after a decade of enormous upheaval in the educational technology landscape. This special issue of "Education Week" includes the following articles: (1) A Digital Decade; (2) Getting Up to Speed (Andrew Trotter); (3) E-Rate's Imprint Seen in Schools (Andrew Trotter); (4) Teaching Assistants (Rhea R.…

  11. Alabama Kids Count 2001 Data Book.

    ERIC Educational Resources Information Center

    Curtis, Apreill; Bogie, Don

    This Kids Count data book examines statewide trends in well-being for Alabama's children. The statistical portrait is based on 17 indicators in the areas of health, education, safety, and security. The indicators are: (1) infant mortality rate; (2) low weight births; (3) child health index; (4) births to unmarried teens; (5) first grade retention;…

  12. Implementing Graduation Counts: State Progress to Date

    ERIC Educational Resources Information Center

    National Governors Association, 2006

    2006-01-01

    This report provides information on states' progress in implementing the graduation rate all 50 governors agreed by signing the Graduation Counts Compact in 2005 to adopt. The governors undertook this commitment because they understand the imperative to gather more accurate, comparable data on how many of their students graduate from high school…

  13. South Dakota KIDS COUNT Factbook, 1999.

    ERIC Educational Resources Information Center

    Cochran, Carole, Ed.

    This Kids Count fact book examines statewide trends in well-being for South Dakota's children. The statistical portrait is based on 25 indicators in the areas of demographics, health, education, economic status, and safety. The indicators are: (1) population; (2) family profile; (3) poverty thresholds; (4) infant mortality rate; (5) low birth…

  14. KIDS COUNT in Virginia: 1999 Data Book.

    ERIC Educational Resources Information Center

    Action Alliance for Virginia's Children and Youth, Richmond.

    This Kids Count data book examines statewide trends in the well-being of Virginia's children. The statistical portrait is based on five general areas of children's well being: health, safety, education, families, and economic factors. Key indicators in these five areas include: (1) prenatal care rates; (2) low birthweight; (3) child deaths; (4)…

  15. Alabama Kids Count 2002 Data Book.

    ERIC Educational Resources Information Center

    Curtis, Apreill; Bogie, Don

    This Kids Count data book examines statewide trends in well-being of Alabamas children. The statistical portrait is based on 18 indicators in the areas of child health, education, safety, and security: (1) infant mortality rate; (2) low weight births; (3) child health index; (4) births to unmarried teens; (5) first grade retention; (6) school…

  16. County Data Book 1997: Kentucky Kids Count.

    ERIC Educational Resources Information Center

    Kentucky Kids Count Consortium.

    This Kids Count data book examines trends in the well-being of Kentucky's children on a statewide and county basis. An introduction summarizes some of the trends for Kentucky's children in the 1990s. The bulk of the report presents statewide and county data grouped into five categories: (1) poverty rates and programs (persons in poverty; median…

  17. Universal roles of hydrogen in electrochemical performance of graphene: high rate capacity and atomistic origins

    NASA Astrophysics Data System (ADS)

    Ye, Jianchao; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue; Shin, Swanee J.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R. I.; Wood, Brandon C.; Wang, Y. Morris

    2015-11-01

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.

  18. Investigation of factors affecting terrestrial passive sampling device performance and uptake rates in laboratory chambers

    SciTech Connect

    Johnson, K.A.; Weisskopf, C.P.

    1995-12-31

    A rapid sampling method using passive sampling devices (PSDS) for soil contaminant characterization shows extreme promise. The use of PSDs increases ease and speed of analysis, decreases solvent usage and cost, and minimizes the transport of contaminated soils. Time and cost savings allow a high sampling frequency, providing a more thorough site characterization than traditional methods. The authors have conducted both laboratory and field studies with terrestrial PSDS. Laboratory studies demonstrated the concentration and moisture dependence of sampler uptake and provided an estimate of the optimal field sampling time for soils contaminated with polychlorinated biphenyls (PCBs). These PSDs were also used to accurately estimate PCB concentrations at hazardous waste site where concentrations ranged from 0.01 to 200 ug PCB/g soil. However, PSDs in the field had sampling rates approximately three times greater than in the laboratory. As a result several factors affecting PSD sampling rates and/or performance in laboratory chambers were evaluated. The parameters investigated were soil bulk density or compactness, chamber size and air flow. The chemicals used in these studies included two PCB congeners (52 and 153), three organochlorine pesticides (DDT, dieldrin and methoxychlor), three organophosphate pesticides (chlorpyrifos, diazinon and terbufos) and three herbicides (alachlor, atrazine and metolachlor).

  19. Universal roles of hydrogen in electrochemical performance of graphene: high rate capacity and atomistic origins

    PubMed Central

    Ye, Jianchao; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue; Shin, Swanee J.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R.I.; Wood, Brandon C.; Wang, Y. Morris

    2015-01-01

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes. PMID:26536830

  20. Paradoxical roles of hydrogen in electrochemical performance of graphene: High rate capacity and atomistic origins

    SciTech Connect

    Ye, Jianchao C.; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue Y.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R. I.; Wood, Brandon C.; Wang, Y. Morris; Shin, Swanee J.

    2015-11-05

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. Furthermore, these findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.