Science.gov

Sample records for count rate performance

  1. Characterization of the count rate performance of modern gamma cameras

    PubMed Central

    Silosky, M.; Johnson, V.; Beasley, C.; Cheenu Kappadath, S.

    2013-01-01

    Purpose: Evaluation of count rate performance (CRP) is an integral component of gamma camera quality assurance and system deadtime (τ) may be utilized for image correction in quantitative studies. This work characterizes the CRP of three modern gamma cameras and estimates τ using two established methods (decay and dual source) under a variety of experimental conditions. Methods: For the decay method, uncollimated detectors were exposed to a Tc-99m source of relatively high activity and count rates were sampled regularly over 48 h. Input count rate at each time point was based on the lowest observed count rate data point. The input count rate was plotted against the observed count rate and fit via least-squares to the paralyzable detector model (PDM) to estimate τ (rates method). A novel expression for observed counts as a function of measurement time interval was derived, taking into account the PDM and the presence of background but making no assumption regarding input count rate. The observed counts were fit via least-squares to this novel expression to estimate τ (counts method). Correlation and Bland-Altman analyses were performed to assess agreement in estimates of τ between the rates and counts methods. The dependence of τ on energy window definition and incident energy spectrum were characterized. The dual source method was also used to estimate τ and its agreement with estimates from the decay method under identical conditions was also investigated. The dependences of τ on the total activity and the ratio of source activities were characterized. Results: The observed CRP curves for each gamma camera agreed with the PDM at low count rates but deviated substantially from it at high count rates. The estimates of τ determined from the paralyzable portion of the CPR curve using the rates method and the counts method were found to be highly correlated (r = 0.999) but with a small (∼6%) difference. No statistically significant difference was observed

  2. Count rate performance and deadtime analysis of the new 3D PETRRA PET camera

    NASA Astrophysics Data System (ADS)

    Wells, Kevin; Kakana, Christina; Ott, Robert J.; Flower, M.; Divoli, Antigoni; Meriaux, Sebastian; Bateman, J. E.; Stephenson, R.; Duxbury, D.; Spill, E. J.

    2001-12-01

    We report on the count-rate performance of the unique PETRRA positron camera at activities up to 60MBq. The camera consists of two large area detectors, each comprising a tiled array of 10mm thick BaF2 scintillation crystals interfaced to a multi-step avalanche chamber filled with 4.2mbar of pure TMAE vapor. Preliminary results demonstrate coincident count rates of over 80kcps for a cylindrical (20x20cm3) phantom with 50MBq of F-18 in the field-of-view using a 20ns coincidence time window. Each component of the readout cycle has been characterized in terms of dead-time loss. The camera's dead-time related count loss is well-described by a paralysable model with a dead-time of ~500ns. Other sources of count rate loss are also discussed.

  3. 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.}

  4. 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.

  5. Fermi gamma-ray burst monitor detector performance at very high counting rates

    NASA Astrophysics Data System (ADS)

    Bhat, P. N.; Fishman, G. J.; Briggs, M. S.; Connaughton, V.; Meegan, C. A.; Paciesas, W. S.; Wilson-Hodge, C.; Xiong, S.

    2014-11-01

    The Gamma-ray Burst Monitor consists of 12 sodium iodide and 2 bismuth germanate scintillation detectors designed to enhance the scientific returns from Fermi in the study of γ-ray bursts. It has a fixed non-paralyzing dead time of 2.604 μs for each detected event except for those in the overflow channel of the 12 bit analog to digital converter of each detector, which have a longer dead time of 10.42 μs. At very high counting rates the pulse pile-up effect in the detectors leads to spectral distortions and also to additional event losses. These effects are relevant for the spectral analysis of high-flux astrophysical events such as gamma-ray bursts, soft gamma repeaters and solar flares, as well as terrestrial gamma-ray flashes. In this paper we present the results of post-launch tests using engineering detectors and equipment on the ground, along with detailed simulations of these effects at very high counting rates. The simulations enable us to assess the qualitative and quantitative changes in spectral shapes and event losses at different count rates. The observed spectra at various count rates using high intensity radioactive sources such as Cs137 and Co60 agree well with the simulated spectra. We also re-test the analytical model developed previously to correct for the pulse pile-up effects in GBM detectors. We also study the expected spectral distortions of specific spectral models commonly used in GRB analysis, including the Band model and power-law models with and without a high-energy cutoff.

  6. 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.

  7. 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.

  8. Performance of a GM tube based environmental dose rate monitor operating in the Time-To-Count mode

    SciTech Connect

    Zickefoose, J.; Kulkarni, T.; Martinson, T.; Phillips, K.; Voelker, M.

    2015-07-01

    The events at the Fukushima Daiichi power plant in the aftermath of a natural disaster underline the importance of a large array of networked environmental monitors to cover areas around nuclear power plants. These monitors should meet a few basic criteria: have a uniform response over a wide range of gamma energies, have a uniform response over a wide range of incident angles, and have a large dynamic range. Many of these criteria are met if the probe is qualified to the international standard IEC 60532 (Radiation protection instrumentation - Installed dose rate meters, warning assemblies and monitors - X and gamma radiation of energy between 50 keV and 7 MeV), which specifically deals with energy response, angle of incidence, dynamic range, response time, and a number of environmental characteristics. EcoGamma is a dual GM tube environmental gamma radiation monitor designed specifically to meet the requirements of IEC 60532 and operate in the most extreme conditions. EcoGamma utilizes two energy compensated GM tubes operating with a Time-To-Count (TTC) collection algorithm. The TTC algorithm extends the lifetime and range of a GM tube significantly and allows the dual GM tube probe to achieve linearity over approximately 10 decades of gamma dose rate (from the Sv/hr range to 100 Sv/hr). In the TTC mode of operation, the GM tube is not maintained in a biased condition continuously. This is different from a traditional counting system where the GM tube is held at a constant bias continuously and the total number of strikes that the tube registers are counted. The traditional approach allows for good sensitivity, but does not lend itself to a long lifetime of the tube and is susceptible to linearity issues at high count rates. TTC on the other hand only biases the tube for short periods of time and in effect measures the time between events, which is statistically representative of the total strike rate. Since the tube is not continually biased, the life of the tube

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

    USGS Publications Warehouse

    Millard, H.T.

    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.

  10. 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

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

    PubMed

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

    2015-03-01

    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. 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(3) Radcal(®) 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(3) calibrated ionization chamber to measure the

  12. 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.

  13. 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.

  14. [Count rate characteristics and count loss correction of Positologica II: a whole body positron emission tomograph].

    PubMed

    Endo, M; Nohara, N; Iinuma, T A; Shinoto, H; Tanaka, E; Yoshida, K; Himi, T; Kagaya, A; Ogushi, A; Inoue, S

    1987-05-01

    This paper describes evaluation and correction of count rate characteristics of POSITOLOGICA II, a multi-slice whole body positron emission tomography system. The present study was performed using three phantoms; a 5 cm inner diameter, water-filled lucite cylinder, a 20 cm inner diameter, water-filled lucite cylinder and a chest phantom. After injection of high activity (about 1.85 GBq (50 mCi] of 13N ammonia into each phantom, rates of true coincidence, random coincidence and single photon detections were measured during decay of the isotope through more than two orders of magnitude of activity. At very high levels of activity, count rate characteristics of the system were saturated and limited to 660 kcps of total coincidence rate, which was the sum of rates in on-time and off-time windows, by the FIFO (first-in first-out) output frequency. Below those levels of activity the relationship between count loss and true coincidence rate was not unique but depended on the phantom configurations, suggesting that count loss correction using the above relationship was inadequate for quantitative study. However, the relationship between count loss and single rate was almost independent of the phantom configurations. Thus in conclusion count loss could be corrected using single rate for POSITOLOGICA II. A practical method of count loss correction was also proposed.

  15. High Count Rate Electron Probe Microanalysis.

    PubMed

    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.

  16. Gamma-gamma coincidence performance of LaBr3:Ce scintillation detectors vs HPGe detectors in high count-rate scenarios.

    PubMed

    Drescher, A; Yoho, M; Landsberger, S; Durbin, M; Biegalski, S; Meier, D; Schwantes, J

    2017-04-01

    A radiation detection system consisting of two cerium doped lanthanum bromide (LaBr3:Ce) scintillation detectors in a gamma-gamma coincidence configuration has been used to demonstrate the advantages that coincident detection provides relative to a single detector, and the advantages that LaBr3:Ce detectors provide relative to high purity germanium (HPGe) detectors. Signal to noise ratios of select photopeak pairs for these detectors have been compared to high-purity germanium (HPGe) detectors in both single and coincident detector configurations in order to quantify the performance of each detector configuration. The efficiency and energy resolution of LaBr3:Ce detectors have been determined and compared to HPGe detectors. Coincident gamma-ray pairs from the radionuclides (152)Eu and (133)Ba have been identified in a sample that is dominated by (137)Cs. Gamma-gamma coincidence successfully reduced the Compton continuum from the large (137)Cs peak, revealed several coincident gamma energies characteristic of these nuclides, and improved the signal-to-noise ratio relative to single detector measurements. LaBr3:Ce detectors performed at count rates multiple times higher than can be achieved with HPGe detectors. The standard background spectrum consisting of peaks associated with transitions within the LaBr3:Ce crystal has also been significantly reduced. It is shown that LaBr3:Ce detectors have the unique capability to perform gamma-gamma coincidence measurements in very high count rate scenarios, which can potentially benefit nuclear safeguards in situ measurements of spent nuclear fuel.

  17. Gamma-gamma coincidence performance of LaBr3:Ce scintillation detectors vs HPGe detectors in high count-rate scenarios

    DOE PAGES

    Drescher, A.; Yoho, M.; Landsberger, S.; ...

    2017-01-15

    In this study, a radiation detection system consisting of two cerium doped lanthanum bromide (LaBr3:Ce) scintillation detectors in a gamma-gamma coincidence configuration has been used to demonstrate the advantages that coincident detection provides relative to a single detector, and the advantages that LaBr3:Ce detectors provide relative to high purity germanium (HPGe) detectors. Signal to noise ratios of select photopeak pairs for these detectors have been compared to high-purity germanium (HPGe) detectors in both single and coincident detector configurations in order to quantify the performance of each detector configuration. The efficiency and energy resolution of LaBr3:Ce detectors have been determined andmore » compared to HPGe detectors. Coincident gamma-ray pairs from the radionuclides 152Eu and 133Ba have been identified in a sample that is dominated by 137Cs. Gamma-gamma coincidence successfully reduced the Compton continuum from the large 137Cs peak, revealed several coincident gamma energies characteristic of these nuclides, and improved the signal-to-noise ratio relative to single detector measurements. LaBr3:Ce detectors performed at count rates multiple times higher than can be achieved with HPGe detectors. The standard background spectrum consisting of peaks associated with transitions within the LaBr3:Ce crystal has also been significantly reduced. Finally, it is shown that LaBr3:Ce detectors have the unique capability to perform gamma-gamma coincidence measurements in very high count rate scenarios, which can potentially benefit nuclear safeguards in situ measurements of spent nuclear fuel.« less

  18. Measured count-rate performance of the Discovery STE PET/CT scanner in 2D, 3D and partial collimation acquisition modes.

    PubMed

    Macdonald, L R; Schmitz, R E; Alessio, A M; Wollenweber, S D; Stearns, C W; Ganin, A; Harrison, R L; Lewellen, T K; Kinahan, P E

    2008-07-21

    We measured count rates and scatter fraction on the Discovery STE PET/CT scanner in conventional 2D and 3D acquisition modes, and in a partial collimation mode between 2D and 3D. As part of the evaluation of using partial collimation, we estimated global count rates using a scanner model that combined computer simulations with an empirical live-time function. Our measurements followed the NEMA NU2 count rate and scatter-fraction protocol to obtain true, scattered and random coincidence events, from which noise equivalent count (NEC) rates were calculated. The effect of patient size was considered by using 27 cm and 35 cm diameter phantoms, in addition to the standard 20 cm diameter cylindrical count-rate phantom. Using the scanner model, we evaluated two partial collimation cases: removing half of the septa (2.5D) and removing two-thirds of the septa (2.7D). Based on predictions of the model, a 2.7D collimator was constructed. Count rates and scatter fractions were then measured in 2D, 2.7D and 3D. The scanner model predicted relative NEC variation with activity, as confirmed by measurements. The measured 2.7D NEC was equal or greater than 3D NEC for all activity levels in the 27 cm and 35 cm phantoms. In the 20 cm phantom, 3D NEC was somewhat higher ( approximately 15%) than 2.7D NEC at 100 MBq. For all higher activity concentrations, 2.7D NEC was greater and peaked 26% above the 3D peak NEC. The peak NEC in 2.7D mode occurred at approximately 425 MBq, and was 26-50% greater than the peak 3D NEC, depending on object size. NEC in 2D was considerably lower, except at relatively high activity concentrations. Partial collimation shows promise for improved noise equivalent count rates in clinical imaging without altering other detector parameters.

  19. 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.

  20. Bayesian analysis of energy and count rate data for detection of low count rate radioactive sources.

    PubMed

    Klumpp, John; Brandl, Alexander

    2015-03-01

    A particle counting and detection system is proposed that searches for elevated count rates in multiple energy regions simultaneously. The system analyzes time-interval data (e.g., time between counts), as this was shown to be a more sensitive technique for detecting low count rate sources compared to analyzing counts per unit interval (Luo et al. 2013). Two distinct versions of the detection system are developed. The first is intended for situations in which the sample is fixed and can be measured for an unlimited amount of time. The second version is intended to detect sources that are physically moving relative to the detector, such as a truck moving past a fixed roadside detector or a waste storage facility under an airplane. In both cases, the detection system is expected to be active indefinitely; i.e., it is an online detection system. Both versions of the multi-energy detection systems are compared to their respective gross count rate detection systems in terms of Type I and Type II error rates and sensitivity.

  1. CALCULATING ACCURATE SHUFFLER COUNT RATES WITH APPLICATIONS

    SciTech Connect

    P. M. RINARD

    2001-05-01

    Shufflers are used to assay uranium and other fissile elements in bulk and waste quantities. They normally require physical calibration standards to achieve the most-accurate results, but such standards are generally rare and expensive, so inappropriate standards are often used out of necessity. This paper reports on a new technique that has been developed to calculate accurate count rates, in effect simulating physical standards with rapid and inexpensive calculations. The technique has been benchmarked on existing oxide and metallic standards, used to study a variety of conditions for which standards do not exist, and applied to inventory items needing verification measurements even though appropriate physical standards do not exist.

  2. Count rate limitations in pulsed accelerator fields

    SciTech Connect

    Justus, Alan L

    2010-12-15

    This paper discusses various concepts involved in the counting losses of pulse-counting health physics instrumentation when used within the pulsed radiation environments of typical accelerator fields, in order to pre-establish appropriate limitations in use. Discussed are the 'narrow' pulse and the 'wide' pulse cases, the special effect of neutron moderating assemblies, and the effect of pulse microstructure on the counting losses of the pulse-counting instrumentation. Examples are provided which highlight the various concepts and limitations.

  3. Opcode counting for performance measurement

    SciTech Connect

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

    2016-10-18

    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.

  4. 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.

  5. 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.

  6. 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…

  7. High counting rate resistive-plate chamber

    NASA Astrophysics Data System (ADS)

    Peskov, V.; Anderson, D. F.; Kwan, S.

    1993-05-01

    Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast (less than 1 ns) and have very simple construction: just two parallel metallic plates or mesh electrodes. Depending on the applied voltage they may work either in spark mode or avalanche mode. The advantage of the spark mode of operation is a large signal amplitude from the chamber, the disadvantage is that there is a large dead time (msec) for the entire chamber after an event. The main advantage of the avalanche mode is high rate capability 10(exp 5) counts/mm(sup 2). A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity (greater than 10(exp 10) Omega(cm) materials. In practice RPC's are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm(sup 2), leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm's law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases.

  8. High performance universal analog and counting photodetector for LIDAR applications

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Krutov, Joseph; Godik, Edward; Seemungal, Wayne; Shushakov, Dmitry; Shubin, V. E.

    2005-08-01

    We demonstrate the feasibility of applying the emerging technology of internal discrete amplification to create an efficient, ultra low noise, universal analog and counting photodetector for LIDAR remote sensing. Photodetectors with internal discrete amplification can operate in the linear detection mode with a gain-bandwidth product of up to 1015 and in the photon counting mode with count rates of up to 109 counts/sec. Detectors based on this mechanism could have performance parameters superior to those of conventional avalanche photodiodes and photomultiplier tubes. For silicon photodetector prototypes, measured excess noise factor is as low as 1.02 at gains greater than 100,000. This gives the photodetectors and, consequently, the LIDAR systems new capabilities that could lead to important advances in LIDAR remote sensing.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  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. 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.

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

    PubMed

    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

    2009-05-01

    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.

  19. Rating Variable Performance.

    ERIC Educational Resources Information Center

    Steiner, Dirk D.; Rain, Jeffrey S.

    Many empirical studies have examined factors that influence ratings of performance. This study examined the rating variable performance of a single individual. Serial position of a single poor or good performance in a series of otherwise good or poor performances was manipulated to examine its effects on both ratings and recommended actions toward…

  20. High resolution Ge/Li/ spectrometer reduces rate-dependent distortions at high counting rates

    NASA Technical Reports Server (NTRS)

    Brenner, R.; Larsen, R. N.; Mann, H. M.; Rudnick, S. J.; Sherman, I. S.; Strauss, M. G.

    1968-01-01

    Modified spectrometer system with a low-noise preamplifier reduces rate-dependent distortions at high counting rates, 25,000 counts per second. Pole-zero cancellation minimizes pulse undershoots due to multiple time constants, baseline restoration improves resolution and prevents spectral shifts.

  1. Simulating the Counting Mechanism of PILATUS2 and PILATUS3 Detectors for Improved Count Rate Corrections

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    PILATUS systems are well established as X-ray detectors at most synchrotrons. Their single photon counting capability ensures precise measurements, but introduces a short dead time after each hit, which becomes significant for photon rates above a million per second and pixel. The resulting loss in the number of counted photons can be corrected for by applying corresponding rate correction factors. This article presents 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. For the PILATUS2 detector series the simulation shows good agreement with experimentally determined correction factors for various detector settings at different synchrotrons. The application of more accurate rate correction factors will improve the X-ray data quality at high photon fluxes. Furthermore we report on the simulation of the rate correction factors for the new PILATUS3 systems. The successor of the PILATUS2 detector avoids the paralysation of the counter, and allows for measurements up to a rate of ten million photons per second and pixel. For fast detector settings the simulation is capable of reproducing the data within one to two percent at an incoming photon rate of one million per second and pixel.

  2. Performance of the EIGER single photon counting detector

    NASA Astrophysics Data System (ADS)

    Tinti, G.; Bergamaschi, A.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Johnson, I.; Jungmann-Smith, J. H.; Mezza, D.; Mozzanica, A.; Schmitt, B.; Shi, X.

    2015-03-01

    EIGER is a single photon counting hybrid pixel detector being developed at Paul Scherrer Institute (PSI), Switzerland, for applications at synchrotron light sources in an energy range from a few to 25 keV. EIGER is characterized by a small pixel size (75 × 75 μm2), a frame rate up to 22 kHz and a small dead time between frames (4 μs). An EIGER module is a hybrid detector composed of a ≈ 8 × 4 cm2 monolithic silicon sensor bump bonded to 4 × 2 readout chips, for a total of 500 kpixels. Each pixel has a configurable depth (up to 12 bits) counter and records the number of photons impinging. Custom designed module electronics reads out the bits in the pixel counter and processes the data in the module before transferring them to a PC. A large dynamic range (32 bits) for the pixel counter can be obtained through on-board image summation. Rate corrections can be applied on-board to compensate for inefficiencies when the pixel counting rates approach pile-up levels around a million counts per second. The EIGER modules are the building blocks of large area detectors: a 1.5 and a 9 Mpixel systems are under development for the cSAXS beamline at the Swiss Light Source (SLS) at PSI. The very high frame rate capabilities are equally fast for multi-module systems due to the fully parallel data processing.The module calibration will be discussed, with emphasis on the choice of the optimal operation settings as a function of photon energy. The performance regarding threshold dispersion and minimum achievable threshold will be presented. In addition, the progress towards the production of larger multi-module systems will be discussed.

  3. 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.

  4. 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

  5. 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.

  6. 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

    2003-12-07

    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.

  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

    Hsieh, Scott S; Pelc, Norbert J

    2014-06-07

    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.

  9. 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

  10. 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

  11. High count rate γ-ray spectroscopy with LaBr3:Ce scintillation detectors

    NASA Astrophysics Data System (ADS)

    Löher, B.; Savran, D.; Fiori, E.; Miklavec, M.; Pietralla, N.; Vencelj, M.

    2012-09-01

    The applicability of LaBr3:Ce detectors for high count rate γ-ray spectroscopy is investigated. A 3 in.×3 in. LaBr3:Ce detector is used in a test setup with radioactive sources to study the dependence of energy resolution and photo peak efficiency on the overall count rate in the detector. Digitized traces were recorded using a 500 MHz FADC and analysed with digital signal processing methods. Good performance is obtained using standard techniques up to about 500 kHz counting rate. A pile-up correction method is applied to the data in order to further improve the capabilities at even higher rates with a focus on recovering the losses in efficiency due to signal pile-up. It is shown that γ-ray spectroscopy can be performed with only moderate lossen in efficiency and high resolution at count rates even above 1 MHz and that the performance can be enhanced in the region between 500 kHz and 10 MHz by using the applied pile-up correction techniques.

  12. A real-time phoneme counting algorithm and application for speech rate monitoring.

    PubMed

    Aharonson, Vered; Aharonson, Eran; Raichlin-Levi, Katia; Sotzianu, Aviv; Amir, Ofer; Ovadia-Blechman, Zehava

    2017-03-01

    Adults who stutter can learn to control and improve their speech fluency by modifying their speaking rate. Existing speech therapy technologies can assist this practice by monitoring speaking rate and providing feedback to the patient, but cannot provide an accurate, quantitative measurement of speaking rate. Moreover, most technologies are too complex and costly to be used for home practice. We developed an algorithm and a smartphone application that monitor a patient's speaking rate in real time and provide user-friendly feedback to both patient and therapist. Our speaking rate computation is performed by a phoneme counting algorithm which implements spectral transition measure extraction to estimate phoneme boundaries. The algorithm is implemented in real time in a mobile application that presents its results in a user-friendly interface. The application incorporates two modes: one provides the patient with visual feedback of his/her speech rate for self-practice and another provides the speech therapist with recordings, speech rate analysis and tools to manage the patient's practice. The algorithm's phoneme counting accuracy was validated on ten healthy subjects who read a paragraph at slow, normal and fast paces, and was compared to manual counting of speech experts. Test-retest and intra-counter reliability were assessed. Preliminary results indicate differences of -4% to 11% between automatic and human phoneme counting. Differences were largest for slow speech. The application can thus provide reliable, user-friendly, real-time feedback for speaking rate control practice.

  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. The operation of microchannel plates at high count rates

    NASA Astrophysics Data System (ADS)

    Fraser, G. W.; Pain, M. T.; Lees, J. E.; Pearson, J. F.

    1991-08-01

    The measured count rate characteristics of a large number of microchannel plate electron multipliers are compared with the predictions of a universal, paralysable-counter model. Individual plate resistances for the experimental study lie in the range 27-2450 MΩ. The gain behaviour of single channel plates is shown to differ from that of multi-stage MCP detectors. The measured dependence of multi-stage multiplier recovery time on illuminated area is interpreted in terms of inter-channel coupling and of changes in conduction current during plate operation. Our findings have significance for the calibration of particle and photon spectrometers and for the development of future channel plate detectors with extended dynamic range.

  16. A signal processor for high counting rate gamma ray spectroscopy with NaI(T1) detectors

    SciTech Connect

    Drndarevic, V.R.; Ryge, P.; Gozani, T. )

    1988-02-01

    A high counting rate signal processor for prompt gamma neutron activation analysis (PGNAA) using NaI(Tl) detectors is described. The specific application is a very low rate, high energy gamma ray in the presence of a high rate at lower energies, producing pile-up at the energy of interest. Several methods for improving high counting rate performance such as shortening of the detector signal, base line inspection, pile-up rejection and filtering, have been investigated and implemented. The processor was experimentally evaluated at high counting rates. It allows counting rates to 400,000 counts per second without significant distortion of the spectrum due to pile-up and with a minimum of resolution degradation. Through the use of an effective pulse width sensitive pile-up rejector, the already suppressed pile-up effect has been further reduced by a factor of three, while rejecting less than 10% of valid counts. High data throughput makes the processor applicable to on-line process control. Performance has been tested at total counting rates up to 400,000 counts per second, and results are presented.

  17. Statistical evaluation of photon count rate data for nanoscale particle measurement in wastewaters.

    PubMed

    Smeraldi, Josh; Ganesh, Rajagopalan; Safarik, Jana; Rosso, Diego

    2012-01-01

    The dynamic light scattering (DLS) technique can detect the concentration and size distribution of nanoscale particles in aqueous solutions by analyzing photon interactions. This study evaluated the applicability of using photon count rate data from DLS analyses for measuring levels of biogenic and manufactured nanoscale particles in wastewater. Statistical evaluations were performed using secondary wastewater effluent and a Malvern Zetasizer. Dynamic light scattering analyses were performed equally by two analysts over a period of two days using five dilutions and twelve replicates for each dilution. Linearity evaluation using the sixty sample analysis yielded a regression coefficient R(2) = 0.959. The accuracy analysis for various dilutions indicated a recovery of 100 ± 6%. Precision analyses indicated low variance coefficients for the impact of analysts, days, and within sample error. The variation by analysts was apparent only in the most diluted sample (intermediate precision ~12%), where the photon count rate was close to the instrument detection limit. The variation for different days was apparent in the two most concentrated samples, which indicated that wastewater samples must be analyzed for nanoscale particle measurement within the same day of collection. Upon addition of 10 mg l(-1) of nanosilica to wastewater effluent samples, the measured photon count rates were within 5% of the estimated values. The results indicated that photon count rate data can effectively complement various techniques currently available to detect nanoscale particles in wastewaters.

  18. Measuring PET scanner sensitivity; Relating count rates to image signal-to-noise ratios using noise equivalent counts

    SciTech Connect

    Strother, S.C. ); Casey, M.E. ); Hoffman, E.J. . Nuclear Medicine Lab.)

    1990-04-01

    Sensitivity parameters derived from a plot of a scanner's true coincidence count (TCC) rates as a function of activity in a 20 cm cylindrical phantom have no direct link to image quality. Noise equivalent count (NEC) rate curves, which incorporate the noise effects of subtracting the randoms and scatter count components provide a direct link between image signal-to-noise ratios and the scatter, randoms and trues coincidence count rates. The authors have measured TCC and NEC curves with a standardized 20 cm diameter nylon cylinder for five different PET scanners with several scanner-collimator combinations. In addition, the authors have compared TCC and NEC curves on one scanner with those from an Alderson brain phantom.

  19. Noise models for low counting rate coherent diffraction imaging.

    PubMed

    Godard, Pierre; Allain, Marc; Chamard, Virginie; Rodenburg, John

    2012-11-05

    Coherent diffraction imaging (CDI) is a lens-less microscopy method that extracts the complex-valued exit field from intensity measurements alone. It is of particular importance for microscopy imaging with diffraction set-ups where high quality lenses are not available. The inversion scheme allowing the phase retrieval is based on the use of an iterative algorithm. In this work, we address the question of the choice of the iterative process in the case of data corrupted by photon or electron shot noise. Several noise models are presented and further used within two inversion strategies, the ordered subset and the scaled gradient. Based on analytical and numerical analysis together with Monte-Carlo studies, we show that any physical interpretations drawn from a CDI iterative technique require a detailed understanding of the relationship between the noise model and the used inversion method. We observe that iterative algorithms often assume implicitly a noise model. For low counting rates, each noise model behaves differently. Moreover, the used optimization strategy introduces its own artefacts. Based on this analysis, we develop a hybrid strategy which works efficiently in the absence of an informed initial guess. Our work emphasises issues which should be considered carefully when inverting experimental data.

  20. Multipixel silicon avalanche photodiode with ultralow dark count rate at liquid nitrogen temperature.

    PubMed

    Akiba, M; Tsujino, K; Sato, K; Sasaki, M

    2009-09-14

    Multipixel silicon avalanche photodiodes (Si APDs) are novel photodetectors used as silicon photomultipliers (SiPMs), or multipixel photon counter (MPPC), because they have fast response, photon-number resolution, and a high count rate; one drawback, however, is the high dark count rate. We developed a system for cooling an MPPC to liquid nitrogen temperature and thus reduce the dark count rate. Our system achieved dark count rates of <0.2 cps. Here we present the afterpulse probability, counting capability, timing jitter, and photon-number resolution of our system at 78.5 K and 295 K.

  1. 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…

  2. Performance limits of a single photon counting pixel system

    NASA Astrophysics Data System (ADS)

    Chmeissani, M.; Mikulec, B.

    2001-03-01

    X-ray imaging using hybrid pixel detectors in single photon counting mode is a relatively recent and exciting development. The photon counting mode implies that each pixel has a threshold in energy above which a hit is recorded. Sharing of charge between adjacent pixels would therefore lead to a loss of registered hits and for medical imaging applications to a higher patient dose. This explains why the demand for high spatial resolution and consequently small pixel sizes (<100 μm) motivates the Medipix2 collaboration to study the effects of charge sharing between pixels on system performance. Two different simulation codes are used to simulate the energy loss inside the detector and the charge transport towards the pixel electrodes. The largest contribution to the lateral spreading of charge comes from diffusion and can result in a considerable loss of detection efficiency in photon counting systems for small pixel sizes. The Medipix2 collaboration consists of groups from Barcelona, Cagliari, CEA/Leti DEIN, CERN, Freiburg, Glasgow, Mitthögskolan, Napoli, NIKHEF, MRC lab Cambridge, Pisa, Prague and Sassari.

  3. 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.

  4. Counting High School Graduates when Graduates Count: Measuring Graduation Rates under the High Stakes of NCLB.

    ERIC Educational Resources Information Center

    Swanson, Christopher B.; Chaplin, Duncan

    This paper addresses the debate over high school graduation rates, examining how the No Child Left Behind Act of 2001 (NCLB) has redirected attention toward graduation rates. It introduces provisions of the NCLB pertaining to high school graduation, discussing implications from a measurement perspective, and presents strategies for developing a…

  5. Platelet counts, MPV and PDW in culture proven and probable neonatal sepsis and association of platelet counts with mortality rate.

    PubMed

    Ahmad, Mirza Sultan; Waheed, Abdul

    2014-05-01

    To determine frequency of thrombocytopenia and thrombocytosis, the MPV (mean platelet volume) and PDW (platelet distribution width) in patients with probable and culture proven neonatal sepsis and determine any association between platelet counts and mortality rate. Descriptive analytical study. NICU, Fazle Omar Hospital, from January 2011 to December 2012. Cases of culture proven and probable neonatal sepsis, admitted in Fazle Omar Hospital, Rabwah, were included in the study. Platelet counts, MPV and PDW of the cases were recorded. Mortality was documented. Frequencies of thrombocytopenia (< 150000/mm3) and thrombocytosis (> 450000/mm3) were ascertained. Mortality rates in different groups according to platelet counts were calculated and compared by chi-square test to check association. Four hundred and sixty nine patients were included; 68 (14.5%) of them died. One hundred and thirty six (29%) had culture proven sepsis, and 333 (71%) were categorized as probable sepsis. Thrombocytopenia was present in 116 (24.7%), and thrombocytosis was present in 36 (7.7%) cases. Median platelet count was 213.0/mm3. Twenty eight (27.7%) patients with thrombocytopenia, and 40 (12.1%) cases with normal or raised platelet counts died (p < 0.001). Median MPV was 9.30, and median PDW was 12.30. MPV and PDW of the patients who died and who were discharged were not significantly different from each other. Thrombocytopenia is a common complication of neonatal sepsis. Those with thrombocytopenia have higher mortality rate. No significant difference was present between PDW and MPV of the cases who survived and died.

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

    USGS Publications Warehouse

    Hatfield, J.S.; Gould, W.R.; 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.

  7. 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.

  8. 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…

  9. Quantifying freestyle kick-count and kick-rate patterns in Paralympic swimming.

    PubMed

    Fulton, Sacha K; Pyne, David B; Burkett, Brendan

    2009-11-01

    Swimming speed is a function of the propulsion generated from arm strokes and leg kicks. Kicking is partially obscured underwater, making the kinematics of the kick difficult to analyse. In this study, we quantified 100-m freestyle kick-count and kick-rate patterns for 14 Paralympic swimmers using inertial-sensor technology. Swimmers took 145 +/- 39 kicks (mean +/- s) for swimming trials and 254 +/- 74 kicks for kicking-only trials. Kick rate was 124.9 +/- 20.3 kicks . min(-1) for swimming trials and 129.6 +/- 14.0 kicks . min(-1) for kicking-only trials. There were no marked differences in kick count among 25-m segments in the swimming trials. There was a substantial increase of 10.6%[90% confidence interval (90%CI): 7.3 to 14.0%] in the number of kicks in the kicking-only trials by the fourth 25-m segment. There was a substantial decrease in kick rate by the third 25-m segment for swimming (-12.0%; 90%CI: -12.8 to -11.1%) and kicking-only (-7.3%; 90%CI: -8.6 to -5.9%) trials. The relationship between swimming and kicking-only kick rates was r = 0.67 (0.55 to 0.76; P < 0.001). The temporal patterns of the kick in kicking only differed from those in swimming; increases in kick rate can improve freestyle swimming performance.

  10. Extended Measurement Capabilities of the Electron Proton Helium INstrument aboard SOHO - Understanding single detector count rates

    NASA Astrophysics Data System (ADS)

    Kühl, P.; Banjac, S.; Heber, B.; Labrenz, J.; Müller-Mellin, R.; Terasa, C.

    Forbush (1937) was the first to observe intensity decreases lasting for a few days utilizing ionization chambers. A number of studies on Forbush decreases (FDs) have been performed since then utilizing neutron monitors and space instrumentation. The amplitude of these variations can be as low as a few permil. Therefore intensity measurements need to be of high statistical accuracy. Richardson et al. (1996) suggested therefore to utilize the single counter measurements of the guard counters of the IMP 8 and Helios E6 instruments. Like the above mentioned instruments the Electron Proton Helium INstrument (EPHIN) provides single counting rates. During the extended solar minimum in 2009 its guard detector counted about 25000~counts/minute, allowing to determine intensity variations of less than 2 permil using 30 minute averages. We performed a GEANT 4 simulation of the instrument in order to determine the energy response of all single detectors. It is shown here that their energy thresholds are much lower than the ones of neutron monitors and therefore we developed a criterion that allows to investigate FDs during quiet time periods.

  11. 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.

  12. Expected count rate for the Self- Interrogation Neutron Resonance Densitometry measurements of spent nuclear fuel

    SciTech Connect

    Rossa, Riccardo; Labeau, Pierre-Etienne; Pauly, Nicolas

    2015-07-01

    The Self-Interrogation Neutron Resonance Densitometry (SINRD) is a passive neutron technique that aims at a direct quantification of {sup 239}Pu in the fuel assemblies by measuring the attenuation of the neutron flux in the energy region close to the 0.3 eV resonance of {sup 239}Pu. The {sup 239}Pu mass is estimated by calculating the SINRD signature, that is the ratio between the neutron flux integrated over the fast energy region and around the 0.3 eV resonance region. The SINRD measurement approach considered in this study consists in introducing a small neutron detector in the central guide tube of a PWR 17x17 fuel assembly. In order to measure the neutron flux in the energy regions defined in the SINRD signature, different detector types are used. The response of a bare {sup 238}U fission chamber is considered for the determination of the fast neutron flux, while other thermal-epithermal detectors wrapped in neutron absorbers are envisaged to measure the neutron flux around the resonance region. This paper provides an estimation of the count rate that can be achieved with the detector types proposed for the SINRD measurement. In the first section a set of detectors are evaluated in terms of count rate and sensitivity to the {sup 239}Pu content, in order to identify the optimal measurement configuration for each detector type. Then a study is performed to increase the count rate by increasing the detector size. The study shows that the highest count rate is achieved by using either {sup 3}He or {sup 10}B proportional counters because of the high neutron efficiency of these detectors. However, the calculations indicate that the biggest contribution to the measurement uncertainty is due to the measurement of the fast neutron flux. Finally, similar sensitivity to the {sup 239}Pu content is obtained by using the different detector types for the measurement of the neutron flux close to the resonance region. Therefore, the count rate associated to each detector type

  13. 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…

  14. 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…

  15. 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…

  16. Note: A high count rate real-time digital processing method for PGNAA data acquisition system.

    PubMed

    Liu, Yuzhe; Chen, Lian; Li, Feng; Liang, Futian; Jin, Ge

    2017-07-01

    The prompt gamma neutron activation analysis (PGNAA) technique is a real-time online method to analyze the composition of industrial materials. This paper presents a data acquisition system with a high count rate and real-time digital processing method for PGNAA. Limited by the decay time of the detector, the ORTEC multi-channel analyzer (MCA) can normally achieve an average count rate of 100 kcps. However, this system uses an electrical technique to increase the average count rate and reduce dead time, and guarantees good accuracy. Since the measuring time is usually limited to about 120 s, in order to accelerate the accumulation rate of spectrum and reduce the statistical error, the average count rate is expected to reach more than 500 kcps.

  17. Note: A high count rate real-time digital processing method for PGNAA data acquisition system

    NASA Astrophysics Data System (ADS)

    Liu, Yuzhe; Chen, Lian; Li, Feng; Liang, Futian; Jin, Ge

    2017-07-01

    The prompt gamma neutron activation analysis (PGNAA) technique is a real-time online method to analyze the composition of industrial materials. This paper presents a data acquisition system with a high count rate and real-time digital processing method for PGNAA. Limited by the decay time of the detector, the ORTEC multi-channel analyzer (MCA) can normally achieve an average count rate of 100 kcps. However, this system uses an electrical technique to increase the average count rate and reduce dead time, and guarantees good accuracy. Since the measuring time is usually limited to about 120 s, in order to accelerate the accumulation rate of spectrum and reduce the statistical error, the average count rate is expected to reach more than 500 kcps.

  18. Performance Ratings and Librarians Rights

    ERIC Educational Resources Information Center

    Peele, David

    1970-01-01

    Two aspects of rating personnel performance are explored: (1) the rating form and some guidelines for filling it in and (2) the right of the librarian who is being rated to discuss or appeal a rating he believes to be biased. (NH)

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

    SciTech Connect

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

    2013-05-15

    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.

  20. 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

  1. Gain reduction due to space charge at high counting rates in multiwire proportional chambers

    SciTech Connect

    Smith, G.C.; Mathieson, E.

    1986-10-01

    Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q/sub 0/)/(q/q/sub 0/), where (q/q/sub 0/) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory.

  2. Source concentration and count rate effects for a nuclear waste monitoring system

    NASA Astrophysics Data System (ADS)

    Koizumi, Carl J.

    2004-01-01

    The United States Department of Energy Grand Junction Office (DOE-GJO) recently developed and deployed a passive total-count γ-ray logging system to monitor subsurface plumes of nuclear waste at the DOE Hanford Site in the state of Washington. High count rate effects for the three thallium-activated sodium iodide (NaI(Tl)) detectors were investigated because zones of intense radiation are frequently encountered. Total count rates and "filtered" count rates were determined from γ-ray spectra collected by logging DOE-GJO natural-uranium-bearing calibration standards. Each filtered rate was calculated by dividing the counts in the part of the spectrum above 570 keV by the counting time. Filtered count rates were linear in relation to uranium concentration, even for high uranium concentrations, but total count rates for high uranium concentrations fell below the values predicted by extrapolating the count-rate-versus-uranium-concentration graphs that were nearly linear at lower concentrations. The physics of low energy photon absorption explains why the total count rate did not rise in proportion to the uranium concentration. Low energy photons contribute significantly to the total count and, within calibration standard media, the rate of creation of such photons is proportional to the uranium concentration. However, the low energy photon flux does not grow linearly with the uranium concentration because of the Z effect: An increase in the Z (average atomic number) of a medium is accompanied by a large increase in the fraction of low energy photons absorbed in the medium. Elevated Z values are obviously associated with elevated uranium concentrations because uranium has a high atomic number. Logging systems with high-purity germanium (HPGe) detectors that are also operated by DOE-GJO to assess nuclear waste at the Hanford Site are calibrated using DOE uranium-bearing standards. With spectra associated with uranium activities higher than about 2000 pCi/g, line

  3. A High Count Rate Neutron Beam Monitor for Neutron Scattering Facilities

    SciTech Connect

    Barnett, Amanda; Crow, Lowell; Diawara, Yacouba; Hayward, J P; Hayward, Jason P; Menhard, Kocsis; Sedov, Vladislav N; Funk, Loren L

    2013-01-01

    Abstract Beam monitors are an important diagnostic tool in neutron science facilities. Present beam monitors use either ionization chambers in integration mode, which are slow and have no timing information, or pulse counters which can easily be saturated by high beam intensities. At high flux neutron scattering facilities, neutron beam monitors with very low intrinsic efficiency (10-5) are presently selected to keep the counting rate within a feasible range, even when a higher efficiency would improve the counting statistics and yield a better measurement of the incident beam. In this work, we report on a high count rate neutron beam monitor. This beam monitor offers good timing with an intrinsic efficiency of 10-3 and a counting rate capability of over 1,000,000 cps without saturation.

  4. 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.

  5. 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.

  6. A New Statistics-Based Online Baseline Restorer for a High Count-Rate Fully Digital System.

    PubMed

    Li, Hongdi; Wang, Chao; Baghaei, Hossain; Zhang, Yuxuan; Ramirez, Rocio; Liu, Shitao; An, Shaohui; Wong, Wai-Hoi

    2010-04-01

    The goal of this work is to develop a novel, accurate, real-time digital baseline restorer using online statistical processing for a high count-rate digital system such as positron emission tomography (PET). In high count-rate nuclear instrumentation applications, analog signals are DC-coupled for better performance. However, the detectors, pre-amplifiers and other front-end electronics would cause a signal baseline drift in a DC-coupling system, which will degrade the performance of energy resolution and positioning accuracy. Event pileups normally exist in a high-count rate system and the baseline drift will create errors in the event pileup-correction. Hence, a baseline restorer (BLR) is required in a high count-rate system to remove the DC drift ahead of the pileup correction. Many methods have been reported for BLR from classic analog methods to digital filter solutions. However a single channel BLR with analog method can only work under 500 kcps count-rate, and normally an analog front-end application-specific integrated circuits (ASIC) is required for the application involved hundreds BLR such as a PET camera. We have developed a simple statistics-based online baseline restorer (SOBLR) for a high count-rate fully digital system. In this method, we acquire additional samples, excluding the real gamma pulses, from the existing free-running ADC in the digital system, and perform online statistical processing to generate a baseline value. This baseline value will be subtracted from the digitized waveform to retrieve its original pulse with zero-baseline drift. This method can self-track the baseline without a micro-controller involved. The circuit consists of two digital counter/timers, one comparator, one register and one subtraction unit. Simulation shows a single channel works at 30 Mcps count-rate with pileup condition. 336 baseline restorer circuits have been implemented into 12 field-programmable-gate-arrays (FPGA) for our new fully digital PET system.

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. ChromAIX2: A large area, high count-rate energy-resolving photon counting ASIC for a Spectral CT Prototype

    NASA Astrophysics Data System (ADS)

    Steadman, Roger; Herrmann, Christoph; Livne, Amir

    2017-08-01

    Spectral CT based on energy-resolving photon counting detectors is expected to deliver additional diagnostic value at a lower dose than current state-of-the-art CT [1]. The capability of simultaneously providing a number of spectrally distinct measurements not only allows distinguishing between photo-electric and Compton interactions but also discriminating contrast agents that exhibit a K-edge discontinuity in the absorption spectrum, referred to as K-edge Imaging [2]. Such detectors are based on direct converting sensors (e.g. CdTe or CdZnTe) and high-rate photon counting electronics. To support the development of Spectral CT and show the feasibility of obtaining rates exceeding 10 Mcps/pixel (Poissonian observed count-rate), the ChromAIX ASIC has been previously reported showing 13.5 Mcps/pixel (150 Mcps/mm2 incident) [3]. The ChromAIX has been improved to offer the possibility of a large area coverage detector, and increased overall performance. The new ASIC is called ChromAIX2, and delivers count-rates exceeding 15 Mcps/pixel with an rms-noise performance of approximately 260 e-. It has an isotropic pixel pitch of 500 μm in an array of 22×32 pixels and is tile-able on three of its sides. The pixel topology consists of a two stage amplifier (CSA and Shaper) and a number of test features allowing to thoroughly characterize the ASIC without a sensor. A total of 5 independent thresholds are also available within each pixel, allowing to acquire 5 spectrally distinct measurements simultaneously. The ASIC also incorporates a baseline restorer to eliminate excess currents induced by the sensor (e.g. dark current and low frequency drifts) which would otherwise cause an energy estimation error. In this paper we report on the inherent electrical performance of the ChromAXI2 as well as measurements obtained with CZT (CdZnTe)/CdTe sensors and X-rays and radioactive sources.

  12. 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.

  13. 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.

  14. Ex vivo radioactive counts and decay rates of tissues resected during radioguided parathyroidectomy.

    PubMed

    Olson, Jordan; Repplinger, Dan; Bianco, Jesus; Chen, Herbert

    2006-12-01

    Radioguided parathyroidectomy using TC-99m-sestamibi injection and the handheld gamma probe allows more precise and rapid intraoperative localization of abnormal parathyroid glands. This technique is based on the principle that hypercellular parathyroid tissues have markedly higher in vivo radiotracer counts than surrounding tissue including thyroid and lymph nodes. While in vivo radioactivity after TC-99m-sestamibi administration in various tissues has been documented, there is a lack of data regarding ex vivo radioactive properties after surgical resection. During a 6-week period in June/July 2005, 21 patients underwent radioguided parathyroidectomy by a single surgeon. Fifty-four tissue samples (39 parathyroid, 15 nonparathyroid) from these patients were collected and analyzed for ex vivo radioactive counts over a 30-min period. These data were then compared with the pathologic results. There is a significant difference in ex vivo counts between parathyroid adenomas, hyperplastic glands, and nonparathyroid tissue immediately after resection. However, radioactive decay/slope rates do not differ between the tissues. Importantly, an ex vivo count of >20% of background is 100% specific for parathyroid tissue. These differences persisted for up to 30 min. This is the first comprehensive study of ex vivo radioactive properties after TC-99m-sestamibi injection during radioguided parathyroidectomy. Parathyroids have a greater rate of uptake compared to nonparathyroid tissue, allowing ex vivo counts to predict tissue type. These tissues have similar decay rates, allowing these predictions to be made anytime up to 30 min after gland resection.

  15. Counting Rate, Naming Rate, Phonological Sensitivity, and Memory Span: Major Factors in Dyslexia.

    ERIC Educational Resources Information Center

    Ackerman, Peggy T.; And Others

    1990-01-01

    Children (N=20, age 9-12) with severe dyslexia were slower in counting from memory and naming alternating digits and letters than children with milder reading impairment. The children most disabled also had poorer phonological sensitivity, shorter digit spans, and lower verbal intelligence quotients. (Author/DB)

  16. Increasing money-counting skills with a student with brain injury: skill and performance deficits.

    PubMed

    Fienup, Daniel M; Mudgal, Dipti; Pace, Gary

    2013-01-01

    Two studies examined the effectiveness of interventions designed to increase money-counting skills of a student with brain injury. Both skill and performance hypotheses were examined. Single subject designs were used to evaluate interventions, including a multiple-baseline across counting paper and coin money (study 1) and a changing criterion design (study 2). In study 1, it was hypothesized that the student had a skill deficit; thus, the participant was taught organizational strategies for counting money. In study 2, a performance deficit was hypothesized and the effects of contingent rewards were evaluated. In study 1, organizational strategies increased organized counting of money, but did not affect counting accuracy. In study 2, contingent rewards increased accurate money counting. When dealing with multi-step behaviours, different components of behaviour can be controlled by different variables, such as skill and performance deficits. Effective academic interventions may need to consider both types of deficits.

  17. 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... OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK What Are the Provisions Addressing...

  18. 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.

  19. 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.

  20. Development of a high-performance multichannel system for time-correlated single photon counting

    NASA Astrophysics Data System (ADS)

    Peronio, P.; Cominelli, A.; Acconcia, G.; Rech, I.; Ghioni, M.

    2017-05-01

    Time-Correlated Single Photon Counting (TCSPC) is one of the most effective techniques for measuring weak and fast optical signals. It outperforms traditional "analog" techniques due to its high sensitivity along with high temporal resolution. Despite those significant advantages, a main drawback still exists, which is related to the long acquisition time needed to perform a measurement. In past years many TCSPC systems have been developed with higher and higher number of channels, aimed to dealing with that limitation. Nevertheless, modern systems suffer from a strong trade-off between parallelism level and performance: the higher the number of channels the poorer the performance. In this work we present the design of a 32x32 TCSPC system meant for overtaking the existing trade-off. To this aim different technologies has been employed, to get the best performance both from detectors and sensing circuits. The exploitation of different technologies will be enabled by Through Silicon Vias (TSVs) which will be investigated as a possible solution for connecting the detectors to the sensing circuits. When dealing with a high number of channels, the count rate is inevitably set by the affordable throughput to the external PC. We targeted a throughput of 10Gb/s, which is beyond the state of the art, and designed the number of TCSPC channels accordingly. A dynamic-routing logic will connect the detectors to the lower number of acquisition chains.

  1. 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).

  2. Statistical analysis of dark count rate in Geiger-mode APD FPAs

    NASA Astrophysics Data System (ADS)

    Itzler, Mark A.; Krishnamachari, Uppili; Chau, Quan; Jiang, Xudong; Entwistle, Mark; Owens, Mark; Slomkowski, Krystyna

    2014-10-01

    We present a temporal statistical analysis of the array-level dark count behavior of Geiger-mode avalanche photodiode (GmAPD) focal plane arrays that distinguishes between Poissonian intrinsic dark count rate and non-Poissonian crosstalk counts by considering "inter-arrival" times between successive counts from the entire array. For 32 x 32 format sensors with 100 μm pixel pitch, we show the reduction of crosstalk for smaller active area sizes within the pixel. We also compare the inter-arrival time behavior for arrays with narrow band (900 - 1100 nm) and broad band (900 - 1600 nm) spectral response. We then consider a similar analysis of larger format 128 x 32 arrays. As a complement to the temporal analysis, we describe the results of a spatial analysis of crosstalk events. Finally, we propose a simple model for the impact of crosstalk events on the Poissonian statistics of intrinsic dark counts that provides a qualitative explanation for the results of the inter-arrival time analysis for arrays with varying degrees of crosstalk.

  3. 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.

  4. 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.

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

    PubMed Central

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

    2012-01-01

    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 106 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 107 photons s−1 pixel−1. PMID:22514168

  6. 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).

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

    PubMed

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

    2013-11-04

    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.

  8. Comparisons of monthly mean cosmic ray counting rates observes from worldwide network of neutron monitors

    NASA Technical Reports Server (NTRS)

    Ryu, J. Y.; Wada, M.

    1985-01-01

    In order to examine the stability of neutron monitor observation, each of the monthly average counting rates of a neutron monitors is correlated to those of Kiel neutron monitor. The regression coefficients thus obtained are compared with the coupling coefficients of isotropic intensity radiation. The results of the comparisons for five year periods during 1963 to 1982, and for whole period are given. The variation spectrum with a single power law with an exponent of -0.75 up to 50 GV is not so unsatisfactory one. More than one half of the stations show correlations with the coefficient greater than 0.9. Some stations have shifted the level of mean counting rates by changing the instrumental characteristics which can be adjusted.

  9. 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

    2016-03-07

    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.

  10. Performance of In-Pixel Circuits for Photon Counting Arrays (PCAs) Based on Polycrystalline Silicon TFTs

    PubMed Central

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

    2017-01-01

    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% FWHM at 70 keV; and the digital components should work well even in the presence of significant 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

  11. 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)

  12. A proposal for harmonising laboratory performance assessment criteria in national asbestos fibre counting schemes.

    PubMed

    Arroyo, M C; Rojo, J M

    2001-08-01

    Four European national asbestos fibre counting proficiency testing schemes have been studied in order to compare their criteria for the assessment of laboratory performance. Performance assessment is based on each laboratory's results after counting a certain number of samples. Two methods are currently being applied. To be classified 'satisfactory' laboratories must obtain at least 75% of normalised counts lying within defined performance limits (in three schemes), or the median and coefficient of variation of normalised counts must be within performance limits (in the fourth scheme). Differences in the numbers of test samples mean that the schemes are operating with different selectivity in assessing their laboratories' performances. Differences in the percentage of laboratory results falling within performance limits indicate that the schemes do not operate the same confidence probability in correctly assessing individual counts. It means that some schemes may be more lenient than others. This paper discusses two proposals to move towards harmonisation of the asbestos fibre counting proficiency testing schemes: (i) standardisation of the number of samples used for laboratory assessment and (ii) changes to the criteria to establish the limits of satisfactory performance.

  13. Investigation of Detector Behaviour At High Count Rates for the Purple Crow Lidar

    NASA Astrophysics Data System (ADS)

    Sica, R. J.; McCullough, E. M.; Jalali, A.; Hartery, S.; Farhani, G.; Argall, P.; Argall, S.

    2013-12-01

    Temperature measurements in the middle and upper atmosphere are an important complement to similar measurements in the lower atmosphere. Even modest size Rayleigh-scatter lidars are capable of high quality measurements of temperature in the stratosphere (above 25 km) and lower mesosphere. The most commonly reported uncertainty, that due to counting statistics, is well understood and affects temperatures at the greatest heights (i.e. lowest signal rates). Counting statistics have a lesser effect on temperatures at the lower range of measurements, where the photocount rate is larger. However, if a lidar's dynamic range is increased by combining analog and digital counting profiles into a 'glued' profile, the gluing introduces a systematic uncertainty. In this presentation we will show the effect of the uncertainty due to gluing on our temperature measurements. The Purple Crow Lidar (PCL), located at the The University of Western Ontario's Echo Base Field Station near London, Canada, has undergone considerable modifications to its transmitter (now a Litron Nd:YAG laser outputting 1 J/pulse at 532 nm with a repetition rate of 30 Hz) as well as to its data acquisition system. The PCL has retained its 2.6 m diameter liquid mercury mirror, giving the system a large power-aperture product. Such a large throughput requires simultaneous analog-digital detection to obtain Rayleigh-scatter temperatures from 25 to above 100 km. The analog and digital profiles must be combined into a single continuous profile, a process called gluing. Several excellent methods for gluing profiles have been presented, but prior to now systematic uncertainties due to the procedure have not been quantified. We will present a detailed characterization of the analog and digital counting channels, using a variety of tests which will show the effect of the gluing procedure on the retrieved temperature.

  14. 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.

  15. A gamma camera count rate saturation correction method for whole-body planar imaging

    PubMed Central

    Hobbs, Robert F; Baechler, Sébastien; Senthamizhchelvan, Srinivasan; Prideaux, Andrew R; Esaias, Caroline E; Reinhardt, Melvin; Frey, Eric C; Loeb, David M; Sgouros, George

    2010-01-01

    Whole-body (WB) planar imaging has long been one of the staple methods of dosimetry, and its quantification has been formalized by the MIRD Committee in pamphlet no 16. One of the issues not specifically addressed in the formalism occurs when the count rates reaching the detector are sufficiently high to result in camera count saturation. Camera dead-time effects have been extensively studied, but all of the developed correction methods assume static acquisitions. However, during WB planar (sweep) imaging, a variable amount of imaged activity exists in the detector’s field of view as a function of time and therefore the camera saturation is time dependent. A new time-dependent algorithm was developed to correct for dead-time effects during WB planar acquisitions that accounts for relative motion between detector heads and imaged object. Static camera dead-time parameters were acquired by imaging decaying activity in a phantom and obtaining a saturation curve. Using these parameters, an iterative algorithm akin to Newton’s method was developed, which takes into account the variable count rate seen by the detector as a function of time. The algorithm was tested on simulated data as well as on a whole-body scan of high activity Samarium-153 in an ellipsoid phantom. A complete set of parameters from unsaturated phantom data necessary for count rate to activity conversion was also obtained, including build-up and attenuation coefficients, in order to convert corrected count rate values to activity. The algorithm proved successful in accounting for motion-and time-dependent saturation effects in both the simulated and measured data and converged to any desired degree of precision. The clearance half-life calculated from the ellipsoid phantom data was calculated to be 45.1 h after dead-time correction and 51.4 h with no correction; the physical decay half-life of Samarium-153 is 46.3 h. Accurate WB planar dosimetry of high activities relies on successfully

  16. Regression analysis of mixed recurrent-event and panel-count data with additive rate models.

    PubMed

    Zhu, Liang; Zhao, Hui; Sun, Jianguo; Leisenring, Wendy; Robison, Leslie L

    2015-03-01

    Event-history studies of recurrent events are often conducted in fields such as demography, epidemiology, medicine, and social sciences (Cook and Lawless, 2007, The Statistical Analysis of Recurrent Events. New York: Springer-Verlag; Zhao et al., 2011, Test 20, 1-42). For such analysis, two types of data have been extensively investigated: recurrent-event data and panel-count data. However, in practice, one may face a third type of data, mixed recurrent-event and panel-count data or mixed event-history data. Such data occur if some study subjects are monitored or observed continuously and thus provide recurrent-event data, while the others are observed only at discrete times and hence give only panel-count data. A more general situation is that each subject is observed continuously over certain time periods but only at discrete times over other time periods. There exists little literature on the analysis of such mixed data except that published by Zhu et al. (2013, Statistics in Medicine 32, 1954-1963). In this article, we consider the regression analysis of mixed data using the additive rate model and develop some estimating equation-based approaches to estimate the regression parameters of interest. Both finite sample and asymptotic properties of the resulting estimators are established, and the numerical studies suggest that the proposed methodology works well for practical situations. The approach is applied to a Childhood Cancer Survivor Study that motivated this study.

  17. Can simple mobile phone applications provide reliable counts of respiratory rates in sick infants and children? An initial evaluation of three new applications.

    PubMed

    Black, James; Gerdtz, Marie; Nicholson, Pat; Crellin, Dianne; Browning, Laura; Simpson, Julie; Bell, Lauren; Santamaria, Nick

    2015-05-01

    Respiratory rate is an important sign that is commonly either not recorded or recorded incorrectly. Mobile phone ownership is increasing even in resource-poor settings. Phone applications may improve the accuracy and ease of counting of respiratory rates. The study assessed the reliability and initial users' impressions of four mobile phone respiratory timer approaches, compared to a 60-second count by the same participants. Three mobile applications (applying four different counting approaches plus a standard 60-second count) were created using the Java Mobile Edition and tested on Nokia C1-01 phones. Apart from the 60-second timer application, the others included a counter based on the time for ten breaths, and three based on the time interval between breaths ('Once-per-Breath', in which the user presses for each breath and the application calculates the rate after 10 or 20 breaths, or after 60s). Nursing and physiotherapy students used the applications to count respiratory rates in a set of brief video recordings of children with different respiratory illnesses. Limits of agreement (compared to the same participant's standard 60-second count), intra-class correlation coefficients and standard errors of measurement were calculated to compare the reliability of the four approaches, and a usability questionnaire was completed by the participants. There was considerable variation in the counts, with large components of the variation related to the participants and the videos, as well as the methods. None of the methods was entirely reliable, with no limits of agreement better than -10 to +9 breaths/min. Some of the methods were superior to the others, with ICCs from 0.24 to 0.92. By ICC the Once-per-Breath 60-second count and the Once-per-Breath 20-breath count were the most consistent, better even than the 60-second count by the participants. The 10-breath approaches performed least well. Users' initial impressions were positive, with little difference between the

  18. 2K×2K resolution element photon counting MCP sensor with >200 kHz event rate capability

    NASA Astrophysics Data System (ADS)

    Vallerga, J. V.; Siegmund, O. H. W.

    2000-03-01

    Siegmund Scientific undertook a NASA Small Business Innovative Research (SBIR) contract to develop a versatile, high-performance photon (or particle) counting detector combining recent technical advances in all aspects of Microchannel Plate (MCP) detector development in a low cost, commercially viable package that can support a variety of applications. The detector concept consists of a set of MCPs whose output electron pulses are read out with a crossed delay line (XDL) anode and associated high-speed event encoding electronics. The delay line anode allows high-resolution photon event centroiding at very high event rates and can be scaled to large formats (>40 mm) while maintaining good linearity and high temporal stability. The optimal sensitivity wavelength range is determined by the choice of opaque photocathodes. Specific achievements included: spatial resolution of <25 μm FWHM; formats from 25 to 40 mm with digitized pixel sizes of ∼3 μm; total detector rates of >200 000 events s-1; local rates of >100 events s-1 per resolution element; event timing of <1 ns; and low background counting rates (<1 event cm-2 s-1).

  19. 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.

  20. 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.

  1. 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... MANAGEMENT Managing Senior Executive Performance § 430.308 Rating performance. (a) Initial summary rating. The supervisor must develop an initial summary rating of the senior executive's performance, in...

  2. 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.

  3. High quantum efficiency and low dark count rate in multi-layer superconducting nanowire single-photon detectors

    SciTech Connect

    Jafari Salim, A. Eftekharian, A.; Hamed Majedi, A.

    2014-02-07

    In this paper, we theoretically show that a multi-layer superconducting nanowire single-photon detector (SNSPD) is capable of approaching characteristics of an ideal SNSPD in terms of the quantum efficiency, dark count, and band-width. A multi-layer structure improves the performance in two ways. First, the potential barrier for thermally activated vortex crossing, which is the major source of dark counts and the reduction of the critical current in SNSPDs is elevated. In a multi-layer SNSPD, a vortex is made of 2D-pancake vortices that form a stack. It will be shown that the stack of pancake vortices effectively experiences a larger potential barrier compared to a vortex in a single-layer SNSPD. This leads to an increase in the experimental critical current as well as significant decrease in the dark count rate. In consequence, an increase in the quantum efficiency for photons of the same energy or an increase in the sensitivity to photons of lower energy is achieved. Second, a multi-layer structure improves the efficiency of single-photon absorption by increasing the effective optical thickness without compromising the single-photon sensitivity.

  4. 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…

  5. 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…

  6. 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…

  7. Effective Count-Rates for PET Scanners with Reduced and Extended Axial Field of View

    PubMed Central

    MacDonald, LR; Harrison, RL; Alessio, AM; Hunter, WCJ; Lewellen, TK; Kinahan, PE

    2011-01-01

    We investigated the relationship between noise equivalent counts (NEC) and axial field of view (AFOV) for PET scanners with AFOVs ranging from one-half to twice those of current clinical scanners. PET scanners with longer or shorter AFOVs could fulfill different clinical needs depending on exam volumes and site economics. Using previously validated Monte Carlo simulations, we modeled true, scattered, and random coincidence counting rates for a PET ring diameter of 88 cm with 2, 4, 6, and 8 rings of detector blocks (AFOV 7.8, 15.5, 23.3, and 31.0 cm). Fully 3D acquisition mode was compared to full collimation (2D) and partial collimation (2.5D) modes. Counting rates were estimated for a 200 cm long version of the 20 cm diameter NEMA countrate phantom and for an anthropomorphic object based on a patient scan. We estimated the live-time characteristics of the scanner from measured count-rate data and applied that estimate to the simulated results to obtain NEC as a function of object activity. We found NEC increased as a quadratic function of AFOV for 3D mode, and linearly in 2D mode. Partial collimation provided the highest overall NEC on the 2-block system and fully 3D mode provided the highest NEC on the 8-block system for clinically relevant activities. On the 4-, and 6-block systems 3D mode NEC was highest up to ~300 MBq in the anthropomorphic phantom, above which 3D NEC dropped rapidly, and 2.5D NEC was highest. Projected total scan time to achieve NEC-density that matches current clinical practice in a typical oncology exam averaged 9, 15, 24, and 61 min for the 8-, 6-, 4-, and 2-block ring systems, when using optimal collimation. Increasing the AFOV should provide a greater than proportional increase in NEC, potentially benefiting patient throughput-to-cost ratio. Conversely, by using appropriate collimation, a two-ring (7.8 cm AFOV) system could acquire whole-body scans achieving NEC-density levels comparable to current standards within long, but feasible

  8. Performance evaluation and result comparison of the automated hematology analyzers Abbott CD 3700, Sysmex XE 2100 and Coulter LH 750 for cell counts in serous fluids.

    PubMed

    Yang, Dagan; Zhou, Yunxian; Chen, Baode

    2013-04-18

    Automated hematology analyzers are used to perform cell counts in body fluids. However, little is known about how the results compare between different analyzers. A single batch of serous fluid samples was used to evaluate the cell counting performance of 3 hematology analyzers: CD 3700, XE 2100, and LH 750. Two hundred and seventy four serous fluid samples were used to evaluate the accuracy of the analyzers and to compare the results between different analyzers. The precision and linearity of the 3 analyzers were acceptable for both white blood cell counts and red blood cell counts with a low carryover rate. The limits of detection for white blood cells with the CD 3700, XE 2100, and LH 750 analyzers were 0.033×10(9)/l, 0.07×10(9)/l, and 0.20×10(9)/l, respectively. Performing background counts had no influence on cell counts for any of the analyzers. For those samples over the limit of detection, there was agreement between the automated and manual counting methods. There were also reasonably comparable cell count results between the 3 analyzers. When the serous fluid cell counts are over the limit of detection, the analyzers produce accurate test results. Additionally, the results are comparable between the 3 hematology analyzers. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. 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.

  10. 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.

  11. Linking reproduction and survival can improve model estimates of vital rates derived from limited time-series counts of pinnipeds and other species.

    PubMed

    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.

  12. 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

  13. Effects of dilution rates, animal species and instruments on the spectrophotometric determination of sperm counts.

    PubMed

    Rondeau, M; Rouleau, M

    1981-06-01

    Using semen from bull, boar and stallion as well as different spectrophotometers, we established the calibration curves relating the optical density of a sperm sample to the sperm count obtained on the hemacytometer. The results show that, for a given spectrophotometer, the calibration curve is not characteristic of the animal species we studied. The differences in size of the spermatozoa are probably too small to account for the anticipated specificity of the calibration curve. Furthermore, the fact that different dilution rates must be used, because of the vastly different concentrations of spermatozoa which is characteristic of those species, has no effect on the calibration curves since the dilution rate is shown to be artefactual. On the other hand, for a given semen, the calibration curve varies depending upon the spectrophotometry used. However, if two instruments have the same characteristic in terms of spectral bandwidth, the calibration curves are not statistically different.

  14. Automated cell counts on CSF samples: A multicenter performance evaluation of the GloCyte system.

    PubMed

    Hod, E A; Brugnara, C; Pilichowska, M; Sandhaus, L M; Luu, H S; Forest, S K; Netterwald, J C; Reynafarje, G M; Kratz, A

    2017-09-07

    Automated cell counters have replaced manual enumeration of cells in blood and most body fluids. However, due to the unreliability of automated methods at very low cell counts, most laboratories continue to perform labor-intensive manual counts on many or all cerebrospinal fluid (CSF) samples. This multicenter clinical trial investigated if the GloCyte System (Advanced Instruments, Norwood, MA), a recently FDA-approved automated cell counter, which concentrates and enumerates red blood cells (RBCs) and total nucleated cells (TNCs), is sufficiently accurate and precise at very low cell counts to replace all manual CSF counts. The GloCyte System concentrates CSF and stains RBCs with fluorochrome-labeled antibodies and TNCs with nucleic acid dyes. RBCs and TNCs are then counted by digital image analysis. Residual adult and pediatric CSF samples obtained for clinical analysis at five different medical centers were used for the study. Cell counts were performed by the manual hemocytometer method and with the GloCyte System following the same protocol at all sites. The limits of the blank, detection, and quantitation, as well as precision and accuracy of the GloCyte, were determined. The GloCyte detected as few as 1 TNC/μL and 1 RBC/μL, and reliably counted as low as 3 TNCs/μL and 2 RBCs/μL. The total coefficient of variation was less than 20%. Comparison with cell counts obtained with a hemocytometer showed good correlation (>97%) between the GloCyte and the hemocytometer, including at very low cell counts. The GloCyte instrument is a precise, accurate, and stable system to obtain red cell and nucleated cell counts in CSF samples. It allows for the automated enumeration of even very low cell numbers, which is crucial for CSF analysis. These results suggest that GloCyte is an acceptable alternative to the manual method for all CSF samples, including those with normal cell counts. © 2017 John Wiley & Sons Ltd.

  15. 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 rating...

  16. 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 rating...

  17. 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 rating...

  18. 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 rating...

  19. 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.

  20. Genetic Modifiers of White Blood Cell Count, Albuminuria and Glomerular Filtration Rate in Children with Sickle Cell Anemia

    PubMed Central

    Flanagan, Jonathan M.; Alvarez, Ofelia A.; Nelson, Stephen C.; Aygun, Banu; Nottage, Kerri A.; George, Alex; Roberts, Carla W.; Piccone, Connie M.; Howard, Thad A.; Davis, Barry R.; Ware, Russell E.

    2016-01-01

    Discovery and validation of genetic variants that influence disease severity in children with sickle cell anemia (SCA) could lead to early identification of high-risk patients, better screening strategies, and intervention with targeted and preventive therapy. We hypothesized that newly identified genetic risk factors for the general African American population could also impact laboratory biomarkers known to contribute to the clinical disease expression of SCA, including variants influencing the white blood cell count and the development of albuminuria and abnormal glomerular filtration rate. We first investigated candidate genetic polymorphisms in well-characterized SCA pediatric cohorts from three prospective NHLBI-supported clinical trials: HUSTLE, SWiTCH, and TWiTCH. We also performed whole exome sequencing to identify novel genetic variants, using both a discovery and a validation cohort. Among candidate genes, DARC rs2814778 polymorphism regulating Duffy antigen expression had a clear influence with significantly increased WBC and neutrophil counts, but did not affect the maximum tolerated dose of hydroxyurea therapy. The APOL1 G1 polymorphism, an identified risk factor for non-diabetic renal disease, was associated with albuminuria. Whole exome sequencing discovered several novel variants that maintained significance in the validation cohorts, including ZFHX4 polymorphisms affecting both the leukocyte and neutrophil counts, as well as AGGF1, CYP4B1, CUBN, TOR2A, PKD1L2, and CD163 variants affecting the glomerular filtration rate. The identification of robust, reliable, and reproducible genetic markers for disease severity in SCA remains elusive, but new genetic variants provide avenues for further validation and investigation. PMID:27711207

  1. Genetic Modifiers of White Blood Cell Count, Albuminuria and Glomerular Filtration Rate in Children with Sickle Cell Anemia.

    PubMed

    Schaefer, Beverly A; Flanagan, Jonathan M; Alvarez, Ofelia A; Nelson, Stephen C; Aygun, Banu; Nottage, Kerri A; George, Alex; Roberts, Carla W; Piccone, Connie M; Howard, Thad A; Davis, Barry R; Ware, Russell E

    2016-01-01

    Discovery and validation of genetic variants that influence disease severity in children with sickle cell anemia (SCA) could lead to early identification of high-risk patients, better screening strategies, and intervention with targeted and preventive therapy. We hypothesized that newly identified genetic risk factors for the general African American population could also impact laboratory biomarkers known to contribute to the clinical disease expression of SCA, including variants influencing the white blood cell count and the development of albuminuria and abnormal glomerular filtration rate. We first investigated candidate genetic polymorphisms in well-characterized SCA pediatric cohorts from three prospective NHLBI-supported clinical trials: HUSTLE, SWiTCH, and TWiTCH. We also performed whole exome sequencing to identify novel genetic variants, using both a discovery and a validation cohort. Among candidate genes, DARC rs2814778 polymorphism regulating Duffy antigen expression had a clear influence with significantly increased WBC and neutrophil counts, but did not affect the maximum tolerated dose of hydroxyurea therapy. The APOL1 G1 polymorphism, an identified risk factor for non-diabetic renal disease, was associated with albuminuria. Whole exome sequencing discovered several novel variants that maintained significance in the validation cohorts, including ZFHX4 polymorphisms affecting both the leukocyte and neutrophil counts, as well as AGGF1, CYP4B1, CUBN, TOR2A, PKD1L2, and CD163 variants affecting the glomerular filtration rate. The identification of robust, reliable, and reproducible genetic markers for disease severity in SCA remains elusive, but new genetic variants provide avenues for further validation and investigation.

  2. 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.

  3. CLARO: an ASIC for high rate single photon counting with multi-anode photomultipliers

    NASA Astrophysics Data System (ADS)

    Baszczyk, M.; Carniti, P.; Cassina, L.; Cotta Ramusino, A.; Dorosz, P.; Fiorini, M.; Gotti, C.; Kucewicz, W.; Malaguti, R.; Pessina, G.

    2017-08-01

    The CLARO is a radiation-hard 8-channel ASIC designed for single photon counting with multi-anode photomultiplier tubes. Each channel outputs a digital pulse when the input signal from the photomultiplier crosses a configurable threshold. The fast return to baseline, typically within 25 ns, and below 50 ns in all conditions, allows to count up to 107 hits/s on each channel, with a power consumption of about 1 mW per channel. The ASIC presented here is a much improved version of the first 4-channel prototype. The threshold can be precisely set in a wide range, between 30 ke- (5 fC) and 16 Me- (2.6 pC). The noise of the amplifier with a 10 pF input capacitance is 3.5 ke- (0.6 fC) RMS. All settings are stored in a 128-bit configuration and status register, protected against soft errors with triple modular redundancy. The paper describes the design of the ASIC at transistor-level, and demonstrates its performance on the test bench.

  4. Assessment of a protocol for routine simultaneous myocardial blood flow measurement and standard myocardial perfusion imaging with rubidium-82 on a high count rate positron emission tomography system.

    PubMed

    Tout, Deborah; Tonge, Christine M; Muthu, Sivakumar; Arumugam, Parthiban

    2012-11-01

    High count rate positron emission tomography (PET) systems offer the potential for accurate myocardial blood flow (MBF) quantification during first-pass dynamic imaging in conjunction with standard rubidium-82 (Rb-82) PET myocardial perfusion imaging (MPI). We investigate the feasibility of this using a Siemens Biograph mCT. Current routine clinical PET MPI is performed with 1480 MBq (40 mCi) Rb-82. Dynamic first-pass images from 217 consecutive patients were reviewed for evidence of detector saturation, indicating that count rate limits had been exceeded. Phantom acquisitions in the presence of high count rates were performed to assess the effect of detector saturation on quantitative accuracy. Accurate MBF quantification and perfusion imaging using current protocols was successful in 85% of clinical cases. Detector block saturation was observed in 15% of cases, and phantom acquisitions indicate that saturation may have an adverse effect on quantitative accuracy. Visualization of transit or pooling of Rb-82 in the vessels in the axilla was the most consistent feature when saturation occurred. Reduction of administered activity to 1110 MBq (30 mCi) and subsequent evaluation of 159 patients ensured successful MBF quantification while maintaining good diagnostic quality perfusion imaging in 99% of cases. MBF quantification and good-quality standard perfusion imaging can be performed on a high count rate PET system using a single-acquisition protocol. The administered activity requires optimization and we recommend 1110 MBq for PET MPI with a Biograph mCT.

  5. 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.

  6. High count-rate study of two TES x-ray microcalorimeters with different transition temperatures

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Jun; Adams, Joseph S.; Bandler, Simon R.; Betancourt-Martinez, Gabriele L.; Chervenak, James A.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, Frederick S.; Sadleir, John E.; Smith, Stephen J.; Wassell, Edward J.

    2017-10-01

    We have developed transition-edge sensor (TES) microcalorimeter arrays with high count-rate capability and high energy resolution to carry out x-ray imaging spectroscopy observations of various astronomical sources and the Sun. We have studied the dependence of the energy resolution and throughput (fraction of processed pulses) on the count rate for such microcalorimeters with two different transition temperatures (T c). Devices with both transition temperatures were fabricated within a single microcalorimeter array directly on top of a solid substrate where the thermal conductance of the microcalorimeter is dependent upon the thermal boundary resistance between the TES sensor and the dielectric substrate beneath. Because the thermal boundary resistance is highly temperature dependent, the two types of device with different T cs had very different thermal decay times, approximately one order of magnitude different. In our earlier report, we achieved energy resolutions of 1.6 and 2.3 eV at 6 keV from lower and higher T c devices, respectively, using a standard analysis method based on optimal filtering in the low flux limit. We have now measured the same devices at elevated x-ray fluxes ranging from 50 Hz to 1000 Hz per pixel. In the high flux limit, however, the standard optimal filtering scheme nearly breaks down because of x-ray pile-up. To achieve the highest possible energy resolution for a fixed throughput, we have developed an analysis scheme based on the so-called event grade method. Using the new analysis scheme, we achieved 5.0 eV FWHM with 96% throughput for 6 keV x-rays of 1025 Hz per pixel with the higher T c (faster) device, and 5.8 eV FWHM with 97% throughput with the lower T c (slower) device at 722 Hz.

  7. Transforming GSC-II Magnitudes into JWST/FGS Count Rates

    NASA Astrophysics Data System (ADS)

    Holfeltz, Sherie T.; Chayer, P.; Nelan, E. P.

    2010-01-01

    The JWST Fine Guidance Sensor (FGS) will provide the positions of guide stars to the spacecraft attitude control system to facilitate the fine pointing of the Observatory. The FGS is an infrared camera operating in an unfiltered passband from 0.6 to 5.3 microns. The ground system will select guide stars from the Guide Star Catalog II (GSC-II), which is an all-sky catalog with three optical passbands (BJ, RF, IN) derived from photographic plates, and from 2MASS. We present a method for predicting a guide star's FGS photon count rate, which is needed to operate the FGS. The method consists of first deriving equations for transforming the GSC-II optical passbands into J, H, and K for stars that are below the 2MASS faint limiting magnitude, based upon fitting the distribution of brighter stars in color-color diagrams using GSC-II and 2MASS photometry. Next, we convolve the BJ, RF, IN and predicted J, H, and K magnitudes (or 2MASS magnitudes if available) for a given star with the wavelength dependent throughput and sensitivity of the telescope and FGS. To estimate the accuracy of this method for stars that are too faint for 2MASS, we compare the predicted J, H, and K magnitudes for a large sample of stars to data from the United Kingdom Infrared Telescope (UKIRT) Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Using synthetic magnitudes computed from Kurucz models for stars of different spectral types, we show that the method should provide reliable FGS count rates.

  8. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Rating performance. 430.208 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 based...

  9. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....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 rating...

  10. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....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 rating...

  11. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....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 rating...

  12. 5 CFR 430.208 - Rating performance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ....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 rating...

  13. The relationship between compost bedded pack performance, management, and bacterial counts.

    PubMed

    Black, R A; Taraba, J L; Day, G B; Damasceno, F A; Newman, M C; Akers, K A; Wood, C L; McQuerry, K J; Bewley, J M

    2014-05-01

    The objective of this study was to assess the relationships among temperature, moisture, carbon-to-nitrogen (C:N) ratio, space per cow, and bacterial counts from bedding material collected from compost bedded pack (CBP) barns. A field survey of 42 routinely aerated CBP barns was conducted in Kentucky between October 2010 and March 2011. Two bedding material samples of 1,064.7 cm(3) each were collected during a single site visit from 9 evenly distributed locations throughout each barn and thoroughly mixed to create a composite sample representative of the entire CBP. Bacterial counts were determined for coliforms, Escherichia coli, streptococci, staphylococci, and Bacillus spp. University of Kentucky Regulatory Services (Lexington) laboratory personnel performed nutrient analyses to determine moisture, carbon, and nitrogen contents. Surface and 10.2-cm pack depth temperatures were collected for each of the 9 evenly distributed locations and the mean calculated to produce a composite temperature. Space per cow was calculated as the total CBP area divided by number of cows housed on the CBP. The GLM procedure of SAS (SAS Institute Inc., Cary, NC) generated models to describe factors affecting bacterial counts. Bacterial counts were 6.3 ± 0.6, 6.0 ± 0.6, 7.2 ± 0.7, 7.9 ± 0.5, and 7.6 ± 0.5 log 10 cfu/g of dry matter for coliform, Escherichia coli, streptococci, staphylococci, and Bacillus spp., respectively. Composite temperature, CBP moisture, C:N ratio, and space per cow had no effect on coliform counts. Escherichia coli reached a peak concentration when the C:N ratio was between 30:1 and 35:1. Staphylococci counts increased as ambient temperature increased. Streptococci counts decreased with increased space per cow and composite temperature and increased with increasing ambient temperature and moisture. Streptococci counts peaked at a C:N ratio ranging from 16:1 to 18:1. Bacillus spp. counts were reduced with increasing moisture, C:N ratio, and ambient

  14. Pulse shape discrimination of Cs2LiYCl6:Ce3+ detectors at high count rate based on triangular and trapezoidal filters

    NASA Astrophysics Data System (ADS)

    Wen, Xianfei; Enqvist, Andreas

    2017-09-01

    Cs2LiYCl6:Ce3+ (CLYC) detectors have demonstrated the capability to simultaneously detect γ-rays and thermal and fast neutrons with medium energy resolution, reasonable detection efficiency, and substantially high pulse shape discrimination performance. A disadvantage of CLYC detectors is the long scintillation decay times, which causes pulse pile-up at moderate input count rate. Pulse processing algorithms were developed based on triangular and trapezoidal filters to discriminate between neutrons and γ-rays at high count rate. The algorithms were first tested using low-rate data. They exhibit a pulse-shape discrimination performance comparable to that of the charge comparison method, at low rate. Then, they were evaluated at high count rate. Neutrons and γ-rays were adequately identified with high throughput at rates of up to 375 kcps. The algorithm developed using the triangular filter exhibits discrimination capability marginally higher than that of the trapezoidal filter based algorithm irrespective of low or high rate. The algorithms exhibit low computational complexity and are executable on an FPGA in real-time. They are also suitable for application to other radiation detectors whose pulses are piled-up at high rate owing to long scintillation decay times.

  15. 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

  16. 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.

  17. Specific absorption rate evaluation for passengers using wireless communication devices inside vehicles with different handedness, passenger counts, and seating locations.

    PubMed

    Leung, Sai-Wing; Diao, Yinliang; Chan, Kwok-Hung; Siu, Yun-Ming; Wu, Yongle

    2012-10-01

    Radiation from mobile phones inside vehicles, which are semiopen metallic enclosures with irregular shapes and apertures, has been a major concern and has warranted investigation in past years. In this paper, the specific absorption rate (SAR) induced in mobile phone users inside a vehicle was evaluated using different scenarios, including handedness, passenger counts, and seating locations. A computer simulation for SAR distributions in a human body was performed based on the finite-difference time-domain method. The SAR values in mobile phone users in free space were also compared to those inside a vehicle; results illustrated that the maximum SAR induced for mobile phone users in a vehicle is 5% higher than those in free space, but the SAR results showed no significant difference for the handedness. By comparing the SAR values between mobile phone users and nonusers inside a vehicle with a passenger count and seating locations, it was observed that the SAR values around the nonusers' body varied much in different situations, and were higher than those in free space, in some circumstances.

  18. Note: Fully integrated active quenching circuit achieving 100 MHz count rate with custom technology single photon avalanche diodes

    NASA Astrophysics Data System (ADS)

    Acconcia, G.; Labanca, I.; Rech, I.; Gulinatti, A.; Ghioni, M.

    2017-02-01

    The minimization of Single Photon Avalanche Diodes (SPADs) dead time is a key factor to speed up photon counting and timing measurements. We present a fully integrated Active Quenching Circuit (AQC) able to provide a count rate as high as 100 MHz with custom technology SPAD detectors. The AQC can also operate the new red enhanced SPAD and provide the timing information with a timing jitter Full Width at Half Maximum (FWHM) as low as 160 ps.

  19. Note: Fully integrated active quenching circuit achieving 100 MHz count rate with custom technology single photon avalanche diodes.

    PubMed

    Acconcia, G; Labanca, I; Rech, I; Gulinatti, A; Ghioni, M

    2017-02-01

    The minimization of Single Photon Avalanche Diodes (SPADs) dead time is a key factor to speed up photon counting and timing measurements. We present a fully integrated Active Quenching Circuit (AQC) able to provide a count rate as high as 100 MHz with custom technology SPAD detectors. The AQC can also operate the new red enhanced SPAD and provide the timing information with a timing jitter Full Width at Half Maximum (FWHM) as low as 160 ps.

  20. Assessing base rates of sexual behavior using the unmatched count technique

    PubMed Central

    Starosta, Amy J.; Earleywine, Mitch

    2014-01-01

    Estimating the prevalence of sexual behaviors is difficult because of self-report biases. This is particularly relevant in assessing high-risk sexual behaviors for the purpose of reducing the transmission and acquisition of sexually transmitted infections (STIs) and HIV/AIDS. The present study employed the unmatched count technique (UCT), which provides estimates of the prevalence of risky sexual behaviors without requiring participants to confess to socially undesirable or stigmatized behaviors. Compared to a standard, anonymous self-report questionnaire, the UCT protocol revealed that people were less likely to notify their partners about STIs or discuss their history of sexual experiences. Effects were particularly large in women suggesting that women may be more likely to misrepresent their sexual behaviors. The findings suggest that conventional, anonymous self-report questionnaire data of base rates of risky sexual behavior and sexual communication are consistently inaccurate. These discrepant base rates suggest that the UCT might provide a better estimate of the frequency of these behaviors. Results suggest that inconsistent sexual behavior is more rampant than anonymous questionnaires suggest. They also underscore the need for improvements in the anonymity of assessment of sexual behaviors, which could in turn improve the targeting of prevention efforts. Results have important public health implications because accurate assessment of sexual behaviors is crucial for developing effective STI prevention interventions among target populations. PMID:25750777

  1. Acute leukemia detection rate by automated blood count parameters and peripheral smear review.

    PubMed

    Rabizadeh, E; Pickholtz, I; Barak, M; Isakov, E; Zimra, Y; Froom, P

    2015-02-01

    It is unclear what minimal criteria will identify all new cases of acute leukemia in adults in various settings. To determine the adult acute leukemia detection rate of the various criteria, we recorded complete blood count (CBC) test results from consecutive patients with leukemia (130 hospitalized patients and 96 outpatients) and from consecutive patients without leukemia (34,827 hospitalized and 33,695 outpatients). Basic criteria for a reflex review (hemoglobin, platelets, and a five-part differential) detected 91% of new hospital leukemia patients (118 of 130) compared to 75% (72 of 96) outpatients. No cases were missed if we did reflex testing when there was either one of the basic criteria or an increased proportion of large unstained cells (LUC), but five cases were missed using the blast flag instead of the LUC. Adding the LUC to basic criteria resulted in the detection of all cases of acute leukemia. The cost of detection of one case of acute leukemia was 1029 and 425 peripheral smear reviews in hospital and outpatients, respectively. We conclude that basic criteria available on most hematology analyzers along with the LUC identify all adult patients with acute leukemia in both hospital and outpatient settings with minimal peripheral smear review rates. © 2014 John Wiley & Sons Ltd.

  2. Assessing base rates of sexual behavior using the unmatched count technique.

    PubMed

    Starosta, Amy J; Earleywine, Mitch

    2014-01-01

    Estimating the prevalence of sexual behaviors is difficult because of self-report biases. This is particularly relevant in assessing high-risk sexual behaviors for the purpose of reducing the transmission and acquisition of sexually transmitted infections (STIs) and HIV/AIDS. The present study employed the unmatched count technique (UCT), which provides estimates of the prevalence of risky sexual behaviors without requiring participants to confess to socially undesirable or stigmatized behaviors. Compared to a standard, anonymous self-report questionnaire, the UCT protocol revealed that people were less likely to notify their partners about STIs or discuss their history of sexual experiences. Effects were particularly large in women suggesting that women may be more likely to misrepresent their sexual behaviors. The findings suggest that conventional, anonymous self-report questionnaire data of base rates of risky sexual behavior and sexual communication are consistently inaccurate. These discrepant base rates suggest that the UCT might provide a better estimate of the frequency of these behaviors. Results suggest that inconsistent sexual behavior is more rampant than anonymous questionnaires suggest. They also underscore the need for improvements in the anonymity of assessment of sexual behaviors, which could in turn improve the targeting of prevention efforts. Results have important public health implications because accurate assessment of sexual behaviors is crucial for developing effective STI prevention interventions among target populations.

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

    PubMed Central

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

    2011-01-01

    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 99mTc (140 keV), 57Co (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 μA 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 τ, a coefficient k that relates the x-ray tube current I to an incident count rate a by a=k×I, and the incident spectrum. The mean pulse shape of all comparators was acquired in a separate study and was used in the model to estimate the

  4. 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

  5. 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

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

    PubMed

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

    2014-09-01

    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. 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. 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 measured with the 22 keV photons

  7. Optimizing Transition-Edge Sensor Design for High Count-Rate Applications

    SciTech Connect

    Smith, Stephen J.; Adams, Joe S.; Bandler, Simon R.; Brekosky, Regis P.; Brown, Ari-D.; Chervenak, James A.; Eckart, Megan E.; Kelley, Richard L.; Kilbourne, Caroline A.; Scott Porter, F.; Finkbeiner, Fred M.; Sadleir, John E.

    2009-12-16

    We are developing transition-edge sensor (TES) X-ray detectors optimized for high count-rate applications. These devices are fabricated on thick (300 {mu}m) Si substrates, resulting in a 20 times increase in thermal conductance to the heat sink compared to our conventional membrane isolated TES's. Operating a TES with higher heat sink conductance requires 4.5 times more bias current. This results in a 2.7 times increase in {beta}, the logarithmic derivative of resistance with respect to current. Noise measurements show a lower limit on the TES excess noise scales as (2{beta}){sup 1/2}, consistent with the near-equilibrium, non-linear expansion of the Ohmic Johnson noise. This is consistent with our membrane devices though the increased {beta} means the theoretical best attainable resolution is degraded by 25-35%. We have tested devices with different contact geometries between the absorber, and the TES and substrate. This allows us to investigate the loss of athermal phonons to the substrate, which can degrade the resolution. Results show a correlation between the stem contact area and a low-energy tail in the spectral response at 5.9 keV due to the athermal phonon loss. In several devices tested we demonstrate a resolution of 4.1-5.6 eV, coupled with detector time constants as fast as 44 {mu}s, representing an increase in detector response by 7 times compared to the membrane devices.

  8. Guidance for storing blood samples in laboratories performing complete blood count with differential.

    PubMed

    Cornet, E; Behier, C; Troussard, X

    2012-12-01

    The complete blood count (CBC) with differential leukocyte count (DIFF) is an important part of clinical laboratory analyses and provides crucial data for clinicians. Delivery time after blood collection and conditions of storage is known to affect the reliability of results of some hematologic parameters. The aim of this study was to assess the variations of hematologic parameters over time and the influence of storage temperature. Blood samples were randomly selected from hospitalized patients and stored at room temperature and at 4 °C. CBC and DIFF were performed on an automated hematology analyzer and the results between the two groups were compared. Samples stored at room temperature showed an important increase in mean corpuscular volume and hematocrit and a decrease in mean corpuscular hemoglobin concentration. Neutrophil counts tended to increase, whereas monocyte counts tended to decrease. Storing samples at 4 °C improved reproducibility over time of all quantitative and qualitative parameters. We also observed that NEUT-X, a routine parameter useful in detecting myelodysplastic syndrome, became unreliable when analyzed 24 h after sample collection. Our results led us to recommend that samples should be analyzed within 6 h, particularly if samples are transported at room temperature. We also recommend storing samples at 4 °C in case of remote CBC analysis, especially in the context of clinical trials. © 2012 Blackwell Publishing Ltd.

  9. Survey material choices in haematology EQA: a confounding factor in automated counting performance assessment

    PubMed Central

    De la Salle, Barbara

    2017-01-01

    The complete blood count (CBC) is one of the most frequently requested tests in laboratory medicine, performed in a range of healthcare situations. The provision of an ideal assay material for external quality assessment is confounded by the fragility of the cellular components of blood, the lack of commutability of stabilised whole blood material and the lack of certified reference materials and methods to which CBC results can be traced. The choice of assay material between fresh blood, extended life assay material and fully stabilised, commercially prepared, whole blood material depends upon the scope and objectives of the EQA scheme. The introduction of new technologies in blood counting and the wider clinical application of parameters from the extended CBC will bring additional challenges for the EQA provider. PMID:28392727

  10. Comparison of pregnancy rates in pre-treatment male infertility and low total motile sperm count at insemination.

    PubMed

    Xiao, Cheng Wei; Agbo, Chioma; Dahan, Michael H

    2016-01-01

    In intrauterine insemination (IUI), total motile sperm count (TMSC) is an important predictor of pregnancy. However, the clinical significance of a poor TMSC on the day of IUI in a patient with prior normal semen analysis (SA) is unclear. We performed this study to determine if these patients perform as poorly as those who had male factor infertility diagnosed prior to commencing treatment. 147 males with two abnormal SA based on the 2010 World Health Organization criteria underwent 356 IUI with controlled ovarian hyper-stimulation (COH). Their pregnancy rates were compared to 120 males who had abnormal TMSC at the time of 265 IUI with COH, in a retrospective university-based study. The two groups were comparable in female age (p = 0.11), duration of infertility (p = 0.17), previous pregnancies (p = 0.13), female basal serum FSH level (p = 0.54) and number of mature follicles on the day of ovulation trigger (p = 0.27). Despite better semen parameters on the day of IUI in the pre-treatment male factor infertility group (TMSC mean ± SD: 61 ± 30 million vs. 3.5 ± 2 million, p < 0.001), pregnancy rates were much higher in the group with low TMSC on the day of IUI (5 % vs. 17 %, p < 0.001). A patient with a recent (within 6 months) normal pre-treatment SA but low TMSC on the day of IUI likely has a reasonable chance to achieve pregnancy, and does not perform as poorly as subjects previously diagnosed with male factor infertility. More studies should be performed to confirm these findings.

  11. 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

  12. Experience with local lymph node assay performance standards using standard radioactivity and nonradioactive cell count measurements.

    PubMed

    Basketter, David; Kolle, Susanne N; Schrage, Arnhild; Honarvar, Naveed; Gamer, Armin O; van Ravenzwaay, Bennard; Landsiedel, Robert

    2012-08-01

    The local lymph node assay (LLNA) is the preferred test for identification of skin-sensitizing substances by measuring radioactive thymidine incorporation into the lymph node. To facilitate acceptance of nonradioactive variants, validation authorities have published harmonized minimum performance standards (PS) that the alternative endpoint assay must meet. In the present work, these standards were applied to a variant of the LLNA based on lymph node cell counts (LNCC) run in parallel as a control with the standard LLNA with radioactivity measurements, with threshold concentrations (EC3) being determined for the sensitizers. Of the 22 PS chemicals tested in this study, 21 yielded the same results from standard radioactivity and cell count measurements; only 2-mercaptobenzothiazole was positive by LLNA but negative by LNCC. Of the 16 PS positives, 15 were positive by LLNA and 14 by LNCC; methylmethacrylate was not identified as sensitizer by either of the measurements. Two of the six PS negatives tested negative in our study by both LLNA and LNCC. Of the four PS negatives which were positive in our study, chlorobenzene and methyl salicylate were tested at higher concentrations than the published PS, whereas the corresponding concentrations resulted in consistent negative results. Methylmethacrylate and nickel chloride tested positive within the concentration range used for the published PS. The results indicate cell counts and radioactive measurements are in good accordance within the same LLNA using the 22 PS test substances. Comparisons with the published PS results may, however, require balanced analysis rather than a simple checklist approach.

  13. Influence of Point Count Length and Repeated Visits on Habitat Model Performance

    Treesearch

    Randy Dettmers; David A. Buehler; John G. Bartlett; Nathan A. Klaus

    1999-01-01

    Point counts are commonly used to monitor bird populations, and a substantial amount of research has investigated how conducting counts for different lengths of time affects the accuracy of these counts and the subsequent ability to monitor changes in population trends. However, little work has been done io assess how changes in count duration affect bird-habitat...

  14. Performance of 3DOSEM and MAP algorithms for reconstructing low count SPECT acquisitions.

    PubMed

    Grootjans, Willem; Meeuwis, Antoi P W; Slump, Cornelis H; de Geus-Oei, Lioe-Fee; Gotthardt, Martin; Visser, Eric P

    2016-12-01

    Low count single photon emission computed tomography (SPECT) is becoming more important in view of whole body SPECT and reduction of radiation dose. In this study, we investigated the performance of several 3D ordered subset expectation maximization (3DOSEM) and maximum a posteriori (MAP) algorithms for reconstructing low count SPECT images. Phantom experiments were conducted using the National Electrical Manufacturers Association (NEMA) NU2 image quality (IQ) phantom. The background compartment of the phantom was filled with varying concentrations of pertechnetate and indiumchloride, simulating various clinical imaging conditions. Images were acquired using a hybrid SPECT/CT scanner and reconstructed with 3DOSEM and MAP reconstruction algorithms implemented in Siemens Syngo MI.SPECT (Flash3D) and Hermes Hybrid Recon Oncology (Hyrid Recon 3DOSEM and MAP). Image analysis was performed by calculating the contrast recovery coefficient (CRC),percentage background variability (N%), and contrast-to-noise ratio (CNR), defined as the ratio between CRC and N%. Furthermore, image distortion is characterized by calculating the aspect ratio (AR) of ellipses fitted to the hot spheres. Additionally, the performance of these algorithms to reconstruct clinical images was investigated. Images reconstructed with 3DOSEM algorithms demonstrated superior image quality in terms of contrast and resolution recovery when compared to images reconstructed with filtered-back-projection (FBP), OSEM and 2DOSEM. However, occurrence of correlated noise patterns and image distortions significantly deteriorated the quality of 3DOSEM reconstructed images. The mean AR for the 37, 28, 22, and 17mm spheres was 1.3, 1.3, 1.6, and 1.7 respectively. The mean N% increase in high and low count Flash3D and Hybrid Recon 3DOSEM from 5.9% and 4.0% to 11.1% and 9.0%, respectively. Similarly, the mean CNR decreased in high and low count Flash3D and Hybrid Recon 3DOSEM from 8.7 and 8.8 to 3.6 and 4.2, respectively

  15. Effects of Rater-Ratee Similarity on Performance Ratings.

    ERIC Educational Resources Information Center

    Zalesny, Mary D.; Kirsch, Michael P.

    Social psychological research on attitude/belief similarity points to perceived similarity between people as leading to greater attraction and more favorable evaluations. When applied to the area of performance evaluations, organizational research on raters and ratees has focused primarily on the characteristics of the participants of the…

  16. 45 CFR 2522.540 - Do the costs of performance measurement or evaluation count towards the statutory cap on...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Do the costs of performance measurement or evaluation count towards the statutory cap on administrative costs? 2522.540 Section 2522.540 Public Welfare... measurement or evaluation count towards the statutory cap on administrative costs? No, the costs...

  17. 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.

  18. 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;…

  19. Time and position resolution of high granularity, high counting rate MRPC for the inner zone of the CBM-TOF wall

    NASA Astrophysics Data System (ADS)

    Petriş, M.; Bartoş, D.; Caragheorgheopol, G.; Deppner, I.; Frühauf, J.; Herrmann, N.; Kiš, M.; Loizeau, P.-A.; Petrovici, M.; Rădulescu, L.; Simion, V.; Simon, C.

    2016-09-01

    Multi-gap RPC prototypes with a multi-strip-electrode readout were developed for the small polar angle region of the CBM-TOF subdetector, the most demanding zone in terms of granularity and counting rate. The prototypes are based on using low resistivity (~ 1010 Ω·cm) glass electrodes for performing in high counting rate environment. The strip width/pitch size was chosen such to fulfill the impedance matching with the front-end electronics and the granularity requirements of the innermost zone of the CBM-TOF wall. The in-beam tests using secondary particles produced in heavy ion collisions on a Pb target at SIS18—GSI Darmstadt and SPS—CERN were focused on the performance of the prototypes in conditions similar to the ones expected at SIS100/FAIR. An efficiency larger than 98% and a system time resolution in the order of 70-80 ps were obtained in high counting rate and high multiplicity environment.

  20. Implementing a Multiplexed System of Detectors for Higher Photon Counting Rates

    DTIC Science & Technology

    2007-01-01

    Schettini, Sergey V. Polyakov, Ivo Pietro Degiovanni, Giorgio Brida , Stefania Castelletto, and Alan Migdall Abstract—Photon counting applications are...addition to the absolute limits imposed by these effects, in practice Giorgio Brida , Stefania Castelletto, Ivo Pietro Degiovanni, and Valentina...secure quantum communication) and foundations of quantum mechanics. Giorgio Brida Giorgio Brida was born in Aosta, Italy, in 1965. He received the

  1. Performance Invalidity Base Rates Among Healthy Undergraduate Research Participants.

    PubMed

    Ross, Thomas P; Poston, Ashley M; Rein, Patricia A; Salvatore, Andrew N; Wills, Nathan L; York, Taylor M

    2016-02-01

    Few studies have examined base rates of suboptimal effort among healthy, undergraduate students recruited for neuropsychological research. An and colleagues (2012, Conducting research with non-clinical healthy undergraduates: Does effort play a role in neuropsychological test performance? Archives of Clinical Neuropsychology, 27, 849-857) reported high rates of performance invalidity (30.8%-55.6%), calling into question the validity of findings generated from samples of college students. In contrast, subsequent studies have reported much lower base rates ranging from 2.6% to 12%. The present study replicated and extended previous work by examining the performance of 108 healthy undergraduates on the Dot Counting Test, Victoria Symptom Validity Test, Word Memory Test, and a brief battery of neuropsychological measures. During initial testing, 8.3% of the sample scored below cutoffs on at least one Performance Validity Test, while 3.7% were classified as invalid at Time 2 (M interval = 34.4 days). The present findings add to a growing number of studies that suggest performance invalidity base rates in samples of non-clinical, healthy college students are much lower than An and colleagues initial findings. Although suboptimal effort is much less problematic than suggested by An and colleagues, recent reports as high as 12% indicate including measures of effort may be of value when using college students as participants. Methodological issues and recommendations for future research are presented.

  2. 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.

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

    PubMed

    Surti, S; Karp, J S

    2005-12-07

    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).

  4. 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.; hide

    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.

  5. 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.

  6. 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.

  7. Prognostic value of resident clinical performance ratings.

    PubMed

    Williams, Reed G; Dunnington, Gary L

    2004-10-01

    This study investigated the concurrent and predictive validity of end-of-rotation (EOR) clinical performance ratings. Surgeon EOR ratings of residents were collected and compared with end-of-year (EOY) progress decisions and to EOR and EOY confidential judgments of resident ability to provide patient care without direct supervision. Eighty percent to 85% of EOR ratings were Excellent or Very Good. Five percent or fewer were Fair or Poor. Almost all residents receiving Excellent or Very Good EOR ratings also received positive EOR judgments about ability to provide patient care without direct supervision. Residents rated Fair or Poor received negative EOR judgments about ability to provide patient care without direct supervision. As the cumulative percent of Good, Fair, and Poor EOR ratings increased, the number of residents promoted without stipulations at the end of the year decreased and the percentage of faculty members who judged the residents capable of providing effective patient care without direct supervision at the end of the year declined. All residents receiving 40% or more EOR ratings below Very Good had stipulations associated with their promotion. Despite use of descriptive anchors on the scale, clinical performance ratings have no direct meaning. Their meaning needs to be established in the same manner as is done in setting normal values for diagnostic tests, ie, by establishing the relationship between EOR ratings and practice outcomes.

  8. Comparing human observer performance in detecting microcalcifications with energy weighting and photon counting breast CT

    NASA Astrophysics Data System (ADS)

    Kalluri, Kesava; Mahd, Mufeed; Glick, Stephen J.

    2012-03-01

    Breast CT (BCT) using a photon counting detector (PCD) has a number of advantages that can potentially improve clinical performance. Previous computer simulation studies showed that the signal to noise ratio (SNR) for microcalcifications is higher with energy weighted photon counting BCT as compared to cesium iodide energy integrating detector (CsI-EID) based BCT. CsI-EID inherently weighs the incident x-ray photons in direct proportion to the energy (contradicting the information content) which is not an optimal approach. PCD do not inherently weigh the incident photons. By choosing optimal energy weights, higher SNR can be achieved for microcalcifications and hence better detectability. In this simulation study, forward projection data of a numerical breast phantom with microcalcifications inserted were acquired using CsI-EID and PCD. The PCD projections were optimally weighed, and reconstructed using filtered back-projection. We compared observer performance in identifying microcalcifications in the reconstructed images using ROC analysis. ROC based results show that the average area(s) under curve(s) (AUC) for AUCPCD based methods are higher than the average AUCCsI-EID method.

  9. 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

  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. 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…

  12. Performance report cards increase adenoma detection rate.

    PubMed

    Sey, Michael Sai Lai; Liu, Andy; Asfaha, Samuel; Siebring, Victoria; Jairath, Vipul; Yan, Brian

    2017-07-01

    Adenoma detection rate (ADR) is an important measure of colonoscopy quality, as are polyp, advanced ADR, and adenocarcinoma detection rates. We investigated whether performance report cards improved these outcome measures. Endoscopists were given report cards comparing their detection rates to the institutional mean on an annual basis. Detection rates were evaluated at baseline, 1 year after report cards (Year 1), and 2 years after report cards (Year 2). Endoscopists were unaware of the study and received no other interventions. The primary outcome was ADR and secondary outcomes were polyp detection rate (PDR), advanced ADR, and adenocarcinoma detection rate. Multivariate regression was performed to adjust for temporal trends in patient, endoscopists, and procedural factors.  Seventeen physicians performed 3,118 screening colonoscopies in patients with positive FOBT or family history of colon cancer. The ADR increased from 34.5 % (baseline) to 39.4 % (Year 1) and 41.2 % (Year 2) ( P  = 0.0037). The PDR increased from 45 % (baseline) to 48.8 % (Year 1) and 51.8 % (Year 2) ( P  = 0.011). There was no significant improvement in advanced ADR or adenocarcinoma detection rates. On multivariate analysis, the ADR increased by 22 % in Year 1 ( P  = 0.03) and 30 % in Year 2 ( P  = 0.008). Among physicians with a baseline ADR < 25 %, improvement in ADR was even greater, increasing 2.2 times by the end of the study ( P  = 0.004). Improvements in ADR were not correlated with specialty although gastroenterologists were 52 % more likely to find an adenoma than general surgeons.  Annual performance report cards increased adenoma detection rates, especially among physicians with low ADR < 25 %.

  13. Controlling Rater Stringency Error in Clinical Performance Rating: Further Validation of a Performance Rating Theory.

    ERIC Educational Resources Information Center

    Cason, Gerald J.; And Others

    Prior research in a single clinical training setting has shown Cason and Cason's (1981) simplified model of their performance rating theory can improve rating reliability and validity through statistical control of rater stringency error. Here, the model was applied to clinical performance ratings of 14 cohorts (about 250 students and 200 raters)…

  14. Re-Visiting the Competence/Performance Debate in the Acquisition of the Counting Principles

    ERIC Educational Resources Information Center

    Le Corre, Mathieu; Van de Walle, Gretchen; Brannon, Elizabeth M.; Carey, Susan.

    2006-01-01

    Advocates of the ''continuity hypothesis'' have argued that innate non-verbal counting principles guide the acquisition of the verbal count list (Gelman & Gallistel, 1978). Some studies have supported this hypothesis, but others have suggested that the counting principles must be constructed anew by each child. Defenders of the continuity…

  15. Historical data decrease complete blood count reflex blood smear review rates without missing patients with acute leukaemia.

    PubMed

    Rabizadeh, Esther; Pickholtz, Itay; Barak, Mira; Froom, Paul

    2013-08-01

    The availability of historical data decreases the rate of blood smear review rates in outpatients, but we are unaware of studies done at referral centres. In the following study, we determined the effect of historical data on the rates of peripheral blood smears over a 3-month period and then the detection rate of patients with acute leukaemia. All results of complete blood counts (CBCs) tested on three ADVIA 120 analyzers at the regional Rabin Medical Centre, Beilinson Campus over a 3-month period were accessed on a computerised laboratory information system. Over a 3-month period, we determined the proportion of total CBC and patients with criteria for a manual differential count and the actual number of peripheral blood smears done. Finally, we determined the proportion of 100 consecutive patients with acute leukaemia detected using our criteria that included limiting reflex testing according to historical data. Over the 3-month period, there were 34,827 tests done in 12,785 patients. Without historical data, our smear rate would have been 24.5%, but with the availability of historical data, the blood smear review rate was 5.6%. The detection rate for cases of acute leukaemia was 100%. We conclude that the availability of previous test results significantly reduces the need for blood smear review without missing any patients with acute leukaemia.

  16. Analysis and correction of count rate reduction during simultaneous MR-PET measurements with the BrainPET scanner.

    PubMed

    Weirich, Christoph; Brenner, Daniel; Scheins, Jürgen; Besancon, Etienne; Tellmann, Lutz; Herzog, Hans; Shah, N Jon

    2012-07-01

    In hybrid magnetic resonance-positron emission tomography (MR-PET) studies with the Siemens 3T MR-BrainPET scanner an instantaneous reduction of the PET sensitivity was observed during execution of certain MR sequences. This interference was investigated in detail with custom-made as well as standard clinical MR sequences. The radio-frequency pulses, the switched gradient fields and the constant magnetic field were examined as the relevant parameters of the magnetic resonance imaging (MRI) system as well as the air temperature within the PET detectors. Our investigation comprised the analysis of the analog PET signals, the total count rates, the geometric distribution of the count rate reduction within the BrainPET detector as well as reconstructed images. The fast switching magnetic field gradients were identified to distort the analog PET detector signals. The measured count rate reduction was found to be less than 3%, but only up to 2% in the case of echo planar imaging sequences, as applied in functional MRI. For clinical sequences routinely used in hybrid MR-BrainPET measurements, a correction method has been designed, implemented, and evaluated .

  17. 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.

  18. 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.

  19. 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.

  20. 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

    2016-08-08

    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.

  1. ChromAIX: a high-rate energy-resolving photon-counting ASIC for spectal computed tomography

    NASA Astrophysics Data System (ADS)

    Steadman, Roger; Herrmann, Christoph; Mülhens, Oliver; Maeding, Dale G.; Colley, James; Firlit, Ted; Luhta, Randy; Chappo, Marc; Harwood, Brian; Kosty, Doug

    2010-04-01

    In Computed Tomography applications a major opportunity has been identified in the exploitation of the spectral information inherently available due to the polychromatic emission of the X-ray tube. Current CT technology based on indirect-conversion and integrating-mode detection can be used to some extent to distinguish the two predominant physical causes of energy-dependent attenuation (photo-electric effect and Compton effect) by using dual-energy techniques, e.g. kVp switching, dual-source or detector stacking. Further improvements can be achieved by transitioning to direct-conversion technologies and counting-mode detection, which inherently exhibits a better signal-to-noise ratio. Further including energy discrimination, enables new applications, which are not feasible with dual-energy techniques, e.g. the possibility to discriminate K-edge features (contrast agents, e.g. Gadolinium) from the other contributions to the x-ray attenuation of a human body. The capability of providing energy-resolved information with more than two different measurements is referred to as Spectral CT. To study the feasibility of Spectral CT, an energy-resolving proprietary photon counting ASIC (ChromAIX) has been designed to provide high count-rate capabilities while offering energy discrimination. The ChromAIX ASIC consists of an arrangement of 4 by 16 pixels with an isotropic pitch of 300 μm. Each pixel contains a number of independent energy discriminators with their corresponding 12-bit counters with continuous read-out capability. Observed Poissonian count-rates exceeding 10 Mcps (corresponding to approximately 27 Mcps incident mean Poisson rate) have been experimentally validated through electrical characterization. The measured noise of 2.6 mVRMS (4 keV FWHM) adheres to specifications. The ChromAIX ASIC has been specifically designed to support direct-converting materials CdZnTe and CdTe.

  2. 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

  3. In ADHD patients performing the Counting Stroop task: a social neuroscience approach.

    PubMed

    Mercadillo, Roberto E; Trujillo, Celia; Sánchez-Cortazar, Julián; Barrios, Fernando A

    2012-10-01

    Attention Deficit/Hyperactivity Disorder (ADHD) symptoms are manifested in social dynamics. In this study, the brain activity of eight child and adolescent patients diagnosed with ADHD was examined while they performed the Counting Stroop task and results were interpreted using social neuroscience premises. Brain activity was identified in frontal, parietal, and temporal regions related to the orienting system of attention and with linguistic, facial recognition, and mnemonic processes. Consistent with previous reports, these patients showed no activation in prefrontal and anterior cingulate cortices related to the executive system of attention. Also, they manifested activation in the insular cortex involving interoceptive processes that may be associated with impulsiveness. Global brain activity involves a network formed during early development and includes experiential components such as learning of rules, reward systems, empathy, and decision making. An integrative assessment of ADHD should consider psychosocial and neurobiological causes integrated into an individual's own experiences assembled throughout life.

  4. Photon counting multienergy x-ray imaging: effect of the characteristic x rays on detector performance.

    PubMed

    Shikhaliev, Polad M; Fritz, Shannon G; Chapman, John W

    2009-11-01

    The purpose of this work was to investigate the effect of characteristic x rays on the performance of photon counting detectors for multienergy x-ray imaging. X-ray and CT systems with photon counting detectors have compelling advantages compared to energy integrating detectors, and cadmium zinc telluride (CZT) detector is the detector of choice. However, current CZT detectors exhibit several limitations that hamper their practical applications. These limitations include hole trapping, high leakage current, and charge sharing between detector pixels. Charge sharing occurs due to the diffusion of charge when it drifts toward the pixel electrodes. It also occurs due to nonlocal reabsorption of characteristic and scattered x rays created in the detector volume. Hole trapping, leakage current, and charge diffusion may potentially have technical solutions. Characteristic x-ray escape and scatter, however, are fundamental in nature and cannot be easily addressed. The x-ray scatter in the CZT material is small at photon energies used in x-ray imaging. Therefore, the remaining major factor is characteristic x ray. Monte Carlo simulations were used for this study. An experimental photon counting multienergy x-ray imaging system was used to compare simulations to experimental results. An x-ray spectrum at 120 kVp tube voltage was used. The x-ray energy range was split into five subregions (energy bins) and Monte Carlo simulations were performed at average x-ray energies corresponding to these energy bins. The detector pixel size was changed within the 0.1-1 mm range, which covered all possible applications including radiography and CT imaging. The pixel shapes included square and strip pixels. For strip pixels, tilted angle irradiation of the CZT detector was also investigated. The characteristic x rays escaped the pixels in approximately 70% of all x-ray interactions for the smallest pixel size of 0.1 mm. The escape fraction decreased to 20% for the largest pixel size of 1

  5. 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.

  6. Correction of dead-time and pile-up in a detector array for constant and rapidly varying counting rates

    NASA Astrophysics Data System (ADS)

    Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Wright, T.

    2015-03-01

    The effect of dead-time and pile-up in counting experiments may become a significant source of uncertainty if not properly taken into account. Although analytical solutions to this problem have been proposed for simple set-ups with one or two detectors, these are limited when it comes to arrays where time correlation between the detector modules is used, and also in situations of variable counting rates. In this paper we describe the dead-time and pile-up corrections applied to the n_TOF Total Absorption Calorimeter (TAC), a 4π γ-ray detector made of 40 BaF2 modules operating at the CERN n_TOF facility. Our method is based on the simulation of the complete signal detection and event reconstruction processes and can be applied as well in the case of rapidly varying counting rates. The method is discussed in detail and then we present its successful application to the particular case of the measurement of 238U(n, γ) reactions with the TAC detector.

  7. Performance of the latest MPPCs with reduced dark counts and improved photon detection efficiency

    NASA Astrophysics Data System (ADS)

    Tsujikawa, T.; Funamoto, H.; Kataoka, J.; Fujita, T.; Nishiyama, T.; Kurei, Y.; Sato, K.; Yamamura, K.; Nakamura, S.

    2014-11-01

    We have tested the performance of two types of the latest Multi-Pixel Photon Counters (MPPCs; measuring 3×3 mm2 in size) developed by Hamamatsu Photonics K.K. The new S12572-050C is a successor to the S10362-33-050C (i.e., conventional 3×3-mm2 pixel MPPC of 50 μm pitch), comprises 3600 Geiger mode avalanche photodiodes (APDs), and also features high gain (up to 1.25×106), a low dark count (up to 106 cps), and improved photon detection efficiency (PDE) by up to 30%. The S12572-015C is a new type of fine-pitch (15 μm) MPPC featuring a wide dynamic range and fast timing response. This paper first presents the detailed performance of these latest MPPCs as photon counting devices. It then describes our fabrication of a prototype detector consisting of a MPPC optically coupled with a Ce:GAGG scintillator. We obtained average FWHM energy resolutions of 7.3% (15 μm) and 6.7% (new-50 μm), as compared to 6.9% (old-50 μm) for 662-keV gamma rays from the 137Cs source, as measured at 20 °C. Moreover, the number of fired pixels for 662-keV gamma rays increased by 30% for the new-50 μm (as compared to the old-50 μm). We confirmed that the low energy threshold improved from 10 keV to 4 keV, when using the latest MPPC device (new-50 μm). We also confirmed that the timing resolution of the new MPPC is 50 ps or even better, as compared to 89 ps of the old MPPC. The results thus confirm that these new types of MPPCs are promising for various applications as scintillation detectors.

  8. 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.

  9. HEPS-BPIX, a single photon counting pixel detector with a high frame rate for the HEPS project

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Zhang, Jie; Ning, Zhe; Lu, Yunpeng; Fan, Lei; Li, Huaishen; Jiang, Xiaoshan; Lan, Allan K.; Ouyang, Qun; Wang, Zheng; Zhu, Kejun; Chen, Yuanbo; Liu, Peng

    2016-11-01

    China's next generation light source, named the High Energy Photon Source (HEPS), is currently under construction. HEPS-BPIX (HEPS-Beijing PIXel) is a dedicated pixel readout chip that operates in single photon counting mode for X-ray applications in HEPS. Designed using CMOS 0.13 μm technology, the chip contains a matrix of 104×72 pixels. Each pixel measures 150 μm×150 μm and has a counting depth of 20 bits. A bump-bonded prototyping detector module with a 300-μm thick silicon sensor was tested in the beamline of Beijing Synchrotron Radiation Facility. A fast stream of X-ray images was demonstrated, and a frame rate of 1.2 kHz was proven, with a negligible dead time. The test results showed an equivalent noise charge of 115 e- rms after bump bonding and a threshold dispersion of 55 e- rms after calibration.

  10. Statistical Properties of SEE Rate Calculation in the Limits of Large and Small Event Counts

    NASA Technical Reports Server (NTRS)

    Ladbury, Ray

    2007-01-01

    This viewgraph presentation reviews the Statistical properties of Single Event Effects (SEE) rate calculations. The goal of SEE rate calculation is to bound the SEE rate, though the question is by how much. The presentation covers: (1) Understanding errors on SEE cross sections, (2) Methodology: Maximum Likelihood and confidence Contours, (3) Tests with Simulated data and (4) Applications.

  11. Supplier Performance Evaluation and Rating System (SPEARS)

    SciTech Connect

    Oged, M.; Warner, D.; Gurbuz, E.

    1993-03-01

    The SSCL Magnet Quality Assurance Department has implemented a Supplier Performance Evaluation and Rating System (SPEARS) to assess supplier performance throughout the development and production stages of the SSCL program. The main objectives of SPEARS are to promote teamwork and recognize performance. This paper examines the current implementation of SPEARS. MSD QA supports the development and production of SSCsuperconducting magnets while implementing the requirements of DOE Order 5700.6C. The MSD QA program is based on the concept of continuous improvement in quality and productivity. The QA program requires that procurement of items and services be controlled to assure conformance to specification. SPEARS has been implemented to meet DOE requirements and to enhance overall confidence in supplier performance. Key elements of SPEARS include supplier evaluation and selection as well as evaluation of furnished quality through source inspection, audit, and receipt inspection. These elements are described in this paper.

  12. 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.

  13. Respirator Performance Rating Tables for Mask Design

    DTIC Science & Technology

    1990-12-01

    minimum exhalation time can be sustained for long periods of time by exercising healthy individuals (Johnson and Curtis, 1978). Another simple...categories. Deno et al. (1981) have shown that independent individual factors determining exercise performance are related by multiplication: FTOT = FIF 2...only a 1% reduction in work rate due to the same resistances for subjects exercising for 1 hour. Wilson et al. I I (19b9A) and van Huss and Heusner

  14. 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…

  15. Performance of coincidence-based PSD on LiF/ZnS Detectors for Multiplicity Counting

    SciTech Connect

    Robinson, Sean M.; Stave, Sean C.; Lintereur, Azaree; Siciliano, Edward R.; Cowles, Christian C.; Kouzes, Richard T.; Behling, Richard S.

    2016-10-06

    Abstract: Mass accountancy measurement is a nuclear nonproliferation application which utilizes coincidence and multiplicity counters to verify special nuclear material declarations. With a well-designed and efficient detector system, several relevant parameters of the material can be verified simultaneously. 6LiF/ZnS scintillating sheets may be used for this purpose due to a combination of high efficiency and short die-away times in systems designed with this material, but involve choices of detector geometry and exact material composition (e.g., the addition of Ni-quenching in the material) that must be optimized for the application. Multiplicity counting for verification of declared nuclear fuel mass involves neutron detection in conditions where several neutrons arrive in a short time window, with confounding gamma rays. This paper considers coincidence-based Pulse-Shape Discrimination (PSD) techniques developed to work under conditions of high pileup, and the performance of these algorithms with different detection materials. Simulated and real data from modern LiF/ZnS scintillator systems are evaluated with these techniques and the relationship between the performance under pileup and material characteristics (e.g., neutron peak width and total light collection efficiency) are determined, to allow for an optimal choice of detector and material.

  16. 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…

  17. 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…

  18. A Comparison of Bird Detection Rates Derived from On-Road vs. Off-Road Point Counts in Northern Montana

    Treesearch

    Richard L. Hutto; Sallie J. Hejl; Jeffrey F. Kelly; Sandra M. Pletschet

    1995-01-01

    We conducted a series of 275 paired (on- and off-road) point counts within 4 distinct vegetation cover types in northwestern Montana. Roadside counts generated a bird list that was essentially the same as the list generated from off-road counts within the same vegetation cover type. Species that were restricted to either on- or off-road counts were rare, suggesting...

  19. TMF ultra-high rate discharge performance

    SciTech Connect

    Nelson, B.

    1997-12-01

    BOLDER Technologies Corporation has developed a valve-regulated lead-acid product line termed Thin Metal Film (TMF{trademark}) technology. It is characterized by extremely thin plates and close plate spacing that facilitate high rates of charge and discharge with minimal temperature increases, at levels unachievable with other commercially-available battery technologies. This ultra-high rate performance makes TMF technology ideal for such applications as various types of engine start, high drain rate portable devices and high-current pulsing. Data are presented on very high current continuous and pulse discharges. Power and energy relationships at various discharge rates are explored and the fast-response characteristics of the BOLDER{reg_sign} cell are qualitatively defined. Short-duration recharge experiments will show that devices powered by BOLDER batteries can be in operation for more than 90% of an extended usage period with multiple fast recharges. The BOLDER cell is ideal for applications such as engine-start, a wide range of portable devices including power tools, hybrid electric vehicles and pulse-power devices. Applications such as this are very attractive, and are well served by TMF technology, but an area of great interest and excitement is ultrahigh power delivery in excess of 1 kW/kg.

  20. Noise performance of low-dose CT: comparison between an energy integrating detector and a photon counting detector using a whole-body research photon counting CT scanner.

    PubMed

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

    2016-10-01

    Photon counting detector (PCD)-based computed tomography (CT) is an emerging imaging technique. Compared to conventional energy integrating detector (EID)-based CT, PCD-CT is able to exclude electronic noise that may severely impair image quality at low photon counts. This work focused on comparing the noise performance at low doses between the PCD and EID subsystems of a whole-body research PCD-CT scanner, both qualitatively and quantitatively. An anthropomorphic thorax phantom was scanned, and images of the shoulder portion were reconstructed. The images were visually and quantitatively compared between the two subsystems in terms of streak artifacts, an indicator of the impact of electronic noise. Furthermore, a torso-shaped water phantom was scanned using a range of tube currents. The product of the noise and the square root of the tube current was calculated, normalized, and compared between the EID and PCD subsystems. Visual assessment of the thorax phantom showed that electronic noise had a noticeably stronger degrading impact in the EID images than in the PCD images. The quantitative results indicated that in low-dose situations, electronic noise had a noticeable impact (up to a 5.8% increase in magnitude relative to quantum noise) on the EID images, but negligible impact on the PCD images.

  1. Tower counts

    USGS Publications Warehouse

    Woody, Carol Ann; Johnson, D.H.; Shrier, Brianna M.; O'Neal, Jennifer S.; Knutzen, John A.; Augerot, Xanthippe; O'Neal, Thomas A.; Pearsons, Todd N.

    2007-01-01

    Counting towers provide an accurate, low-cost, low-maintenance, low-technology, and easily mobilized escapement estimation program compared to other methods (e.g., weirs, hydroacoustics, mark-recapture, and aerial surveys) (Thompson 1962; Siebel 1967; Cousens et al. 1982; Symons and Waldichuk 1984; Anderson 2000; Alaska Department of Fish and Game 2003). Counting tower data has been found to be consistent with that of digital video counts (Edwards 2005). Counting towers do not interfere with natural fish migration patterns, nor are fish handled or stressed; however, their use is generally limited to clear rivers that meet specific site selection criteria. The data provided by counting tower sampling allow fishery managers to determine reproductive population size, estimate total return (escapement + catch) and its uncertainty, evaluate population productivity and trends, set harvest rates, determine spawning escapement goals, and forecast future returns (Alaska Department of Fish and Game 1974-2000 and 1975-2004). The number of spawning fish is determined by subtracting subsistence, sport-caught fish, and prespawn mortality from the total estimated escapement. The methods outlined in this protocol for tower counts can be used to provide reasonable estimates ( plus or minus 6%-10%) of reproductive salmon population size and run timing in clear rivers. 

  2. Relationship between visual counts and call detection rates of gray whales (Eschrichtius robustus) in Laguna San Ignacio, Mexico.

    PubMed

    Ponce, Diana; Thode, Aaron M; Guerra, Melania; Urbán R, Jorge; Swartz, Steven

    2012-04-01

    Daily acoustic calling rates of Eastern North Pacific (ENP) gray whales were measured on 6 days during 1 mo of their 2008 breeding season in the sheltered coastal lagoon of Laguna San Ignacio in Baja California, Mexico. Visual counts of whales determined that the numbers of single animals in the lower lagoon more than tripled over the observation period. All call types showed production peaks in the early morning and evening with minimum rates generally detected in the early afternoon. For four of the five observation days, the daily number of "S1"-type calls increased roughly as the square of the number of the animals in the lower lagoon during both daytime and nighttime. This relationship persisted when raw call counts were adjusted for variations in background noise level, using a simple propagation law derived from empirical measurements. The one observation day that did not fit the square-law relationship occurred during a week when the group size in the lagoon increased rapidly. These results suggest that passive acoustic monitoring does not measure gray whale group size directly but monitors the number of connections in the social network, which rises as roughly M(2)/2 for a group size M.

  3. Dependence of the neutron monitor count rate and time delay distribution on the rigidity spectrum of primary cosmic rays

    NASA Astrophysics Data System (ADS)

    Mangeard, P.-S.; Ruffolo, D.; Sáiz, A.; Nuntiyakul, W.; Bieber, J. W.; Clem, J.; Evenson, P.; Pyle, R.; Duldig, M. L.; Humble, J. E.

    2016-12-01

    Neutron monitors are the premier instruments for precisely tracking time variations in the Galactic cosmic ray flux at GeV-range energies above the geomagnetic cutoff at the location of measurement. Recently, a new capability has been developed to record and analyze the neutron time delay distribution (related to neutron multiplicity) to infer variations in the cosmic ray spectrum as well. In particular, from time delay histograms we can determine the leader fraction L, defined as the fraction of neutrons that did not follow a previous neutron detection in the same tube from the same atmospheric secondary particle. Using data taken during 2000-2007 by a shipborne neutron monitor latitude survey, we observe a strong dependence of the count rate and L on the geomagnetic cutoff. We have modeled this dependence using Monte Carlo simulations of cosmic ray interactions in the atmosphere and in the neutron monitor. We present new yield functions for the count rate of a neutron monitor at sea level. The simulation results show a variation of L with geomagnetic cutoff as observed by the latitude survey, confirming that these changes in L can be attributed to changes in the cosmic ray spectrum arriving at Earth's atmosphere. We also observe a variation in L with time at a fixed cutoff, which reflects the evolution of the cosmic ray spectrum with the sunspot cycle, known as solar modulation.

  4. Improving the assessment of activity in samples with non-uniform distribution using the sum peak count rate.

    PubMed

    Suvaila, Rares; Osvath, Iolanda; Sima, Octavian

    2013-11-01

    In this work a method for the evaluation of the activity when a point source containing (60)Co is located in an unknown position within a sample is developed. The method can be applied if the count rate in the 2,505 keV sum peak has an acceptable uncertainty. It is based on the correlation between the apparent efficiency for the 1,173 keV peak and the ratio of the count rate in the sum peak of 2,505 keV and in the 1,332 keV peak. The correlation was observed in the measurements of a (60)Co point source located in various positions in a soil sample. The measurements were done with a 47% efficiency n-type HPGe detector. The correlation is also observed in the measurements and simulations done with a Compton-suppressed spectrometer having a 100% n-type HPGe detector. The results obtained with the proposed method are less affected by the uncertainty of the position of the point source than the results obtained using the standard methods of activity evaluation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Stimulus generation, ratings, phoneme counts, and group classifications for 696 famous people by British adults over 40 years of age.

    PubMed

    Smith-Spark, James H; Moore, Viv; Valentine, Tim; Sherman, Susan M

    2006-11-01

    Matching stimuli across a range of influencing variables is no less important for studies of face recognition than it is for those of word processing. Whereas a number of corpora exist to allow experimenters to select a carefully controlled set of word stimuli, similar databases for famous faces do not exist. This article, therefore, provides researchers in the area of face recognition with a useful resource on which to base their stimulus selection. In the first phase of the investigation, British adults over 40 years of age were requested to generate the names of famous people (or celebrities) that they thought they would recognize and to write these down. The most frequently named celebrities were then rated by adults from the same age population for familiarity, distinctiveness, and age of acquisition. The result is a database of 696 famous people, with an indication of their relative eminence in the public consciousness and rated for these important variables. Phoneme counts are also provided for each famous person, together with family name frequency counts in the general population, where available. Materials and links may be accessed at www.psychonomic.org/archive.

  6. 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.

  7. Effect of high somatic cell counts on reproductive performance of Chilean dairy cattle.

    PubMed

    Pinedo, P J; Melendez, P; Villagomez-Cortes, J A; Risco, C A

    2009-04-01

    The objectives were to evaluate the effect of high linear somatic cell counts (LNSCC > or =4.5) during early lactation on reproductive performance and to estimate their association with the risk of abortion in a population of central-southern Chilean dairy cattle. The analysis included records from a population of 157 farms and considered 1,127,405 test-day records including 101,944 lactations that began between 1997 and 2006. After data edits, the analyses of calving to first service and calving to conception intervals consisted of 88,633 and 70,877 lactations, respectively. Once controlling for significant variables, time to first breeding was 21.8 d longer in cows with at least 1 high LNSCC before the first breeding compared with controls. Cows with at least 1 high LNSCC before the fertile breeding had an increment in time to conception of 48.7 d and required, on average, 0.49 more services to conceive. The odds of conception at first service in cows with a high LNSCC within 30 d before [after] breeding were 0.85 (0.81 to 0.89; 95% confidence interval ) [0.82 (0.78 to 0.87; 95% confidence interval)] times the odds of conception for cows without a high LNSCC during that period. The Cox proportional hazard model indicated that after correction by calving year, lactation number, and milk yield standardized to 305 d, the risk of pregnancy decreased by 44% if a high LNSCC occurred before breeding. Cows registering a high LNSCC during the first 90 d of gestation had an increased risk of abortion, being 1.22 (1.07 to 1.35; 95% confidence interval) times more likely to abort than nonaffected cows. It is concluded that subclinical mastitis, measured as LNSCC >/=4.5, had a significant effect on reproductive performance in Chilean dairy cattle.

  8. Counting Rate Characteristics and Image Distortion in Preclinical PET Imaging During Radiopharmaceutical Therapy.

    PubMed

    Mellhammar, Emma; Dahlbom, Magnus; Axelsson, Johan; Strand, Sven-Erik

    2016-12-01

    PET may provide important information on the response during radiopharmaceutical therapy (RPT). Emission of radiation from the RPT radionuclide may disturb coincidence detection and impair image resolution. In this study, we tested the feasibility of performing intratherapeutic PET on 3 preclinical PET systems.

  9. 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 were…

  10. 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

  11. 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. © 2016 Society for Psychophysiological Research.

  12. Investigation of quad-energy high-rate photon counting for X-ray computed tomography using a cadmium telluride detector.

    PubMed

    Matsukiyo, Hiroshi; Sato, Eiichi; Oda, Yasuyuki; Yamaguchi, Satoshi; Sato, Yuichi; Hagiwara, Osahiko; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya

    2017-09-10

    To obtain four kinds of tomograms at four different X-ray energy ranges simultaneously, we have constructed a quad-energy (QE) X-ray photon counter with a cadmium telluride (CdTe) detector and four sets of comparators and microcomputers (MCs). X-ray photons are detected using the CdTe detector, and the event pulses produced using amplifiers are sent to four comparators simultaneously to regulate four threshold energies of 20, 33, 50 and 65keV. Using this counter, the energy ranges are 20-33, 33-50, 50-65 and 65-100keV; the maximum energy corresponds to the tube voltage. We performed QE computed tomography (QE-CT) at a tube voltage of 100kV. Using a 0.5-mm-diam lead pinhole, four tomograms were obtained simultaneously at four energy ranges. K-edge CT using iodine and gadolinium media was carried out utilizing two energy ranges of 33-50 and 50-65keV, respectively. At a tube voltage of 100kV and a current of 60 μA, the count rate was 15.2 kilocounts per second (kcps), and the minimum count rates after penetrating objects in QE-CT were regulated to approximately 2 kcps by the tube current. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 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

    2016-07-20

    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.

  14. 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

  15. Performance of a compact position-sensitive photon counting detector with image charge coupling to an air-side anode

    NASA Astrophysics Data System (ADS)

    Jagutzki, O.; Czasch, A.; Schössler, S.

    2013-05-01

    We discuss a novel micro-channel plate (MCP) photomultiplier with resistive screen (RS-PMT) as a detection device for space- and time-correlated single photon counting, illustrated by several applications. The photomultiplier tube resembles a standard image intensifier device. However, the rear phosphor screen is replaced by a ceramic "window" with resistive coating. The MCP output is transferred through the ceramic plate to the read-out electrode (on the air side) via capacity-coupling of the image charge. This design allows for an easy reconfiguration of the read-out electrode (e.g. pixel, charge-sharing, cross-strip, delay-line) without breaking the vacuum for optimizing the detector performance towards a certain task. It also eases the design and manufacturing process of such a multi-purpose photomultiplier tube. Temporal and spatial resolutions well below 100 ps and 100 microns, respectively, have been reported at event rates as high as 1 MHz, for up to 40 mm effective detection diameter. In this paper we will discuss several applications like wide-field fluorescence microscopy and dual γ/fast-neutron radiography for air cargo screening and conclude with an outlook on large-area detectors for thermal neutrons based on MCPs.

  16. When Rating Systems Do Not Rate: Evaluating ERA's Performance

    ERIC Educational Resources Information Center

    Henman, Paul; Brown, Scott D.; Dennis, Simon

    2017-01-01

    In 2015, the Australian Government's Excellence in Research for Australia (ERA) assessment of research quality declined to rate 1.5 per cent of submissions from universities. The public debate focused on practices of gaming or "coding errors" within university submissions as the reason for this outcome. The issue was about the…

  17. 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…

  18. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Estimation of DMFT, Salivary Streptococcus Mutans Count, Flow Rate, Ph, and Salivary Total Calcium Content in Pregnant and Non-Pregnant Women: A Prospective Study.

    PubMed

    Kamate, Wasim Ismail; Vibhute, Nupura Aniket; Baad, Rajendra Krishna

    2017-04-01

    Pregnancy, a period from conception till birth, causes changes in the functioning of the human body as a whole and specifically in the oral cavity that may favour the emergence of dental caries. Many studies have shown pregnant women at increased risk for dental caries, however, specific salivary caries risk factors and the particular period of pregnancy at heightened risk for dental caries are yet to be explored and give a scope of further research in this area. The aim of the present study was to assess the severity of dental caries in pregnant women compared to non-pregnant women by evaluating parameters like Decayed, Missing, Filled Teeth (DMFT) index, salivary Streptococcus mutans count, flow rate, pH and total calcium content. A total of 50 first time pregnant women in the first trimester were followed during their second trimester, third trimester and postpartum period for the evaluation of DMFT by World Health Organization (WHO) scoring criteria, salivary flow rate by drooling method, salivary pH by pH meter, salivary total calcium content by bioassay test kit and salivary Streptococcus mutans count by semiautomatic counting of colonies grown on Mitis Salivarius (MS) agar supplemented by 0.2U/ml of bacitracin and 10% sucrose. The observations of pregnant women were then compared with same parameters evaluated in the 50 non-pregnant women. Paired t-test and Wilcoxon sign rank test were performed to assess the association between the study parameters. Evaluation of different caries risk factors between pregnant and non-pregnant women clearly showed that pregnant women were at a higher risk for dental caries. Comparison of caries risk parameters during the three trimesters and postpartum period showed that the salivary Streptococcus mutans count had significantly increased in the second trimester, third trimester and postpartum period while the mean pH and mean salivary total calcium content decreased in the third trimester and postpartum period. These changes

  20. 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).

  1. Identification and validation of a factor of commutability between platelet counts performed on EDTA and citrate.

    PubMed

    Dumont, Pierre; Goussot, Vincent; David, Alice; Lizard, Sarab; Riedinger, Jean-Marc

    2017-02-01

    The anticoagulant mostly employed for platelet count is EDTA. The Francophone Group of Cellular Hematology recommends checking of blood smear stained with May-Grünwald Giemsa any thrombocytopenia less than 100 G/L without medical history or whether an alarm is generated by the cell counter. The pseudo-thrombocytopenia (PTP) with EDTA is the best known artifact in platelet count. A sample of blood on citrated tube is necessary to get rid of the interference. The objective of this study was to compare the platelet counts obtained on EDTA (numEDTA) and citrate (numCTAD) tubes and to define, then validate a factor of conversion between both methods. The prevalence of PTP EDTA is 0.26%. The PTP was transient in 80% of the patients. The numEDTA and numCTAD+10% (numCTAD increased by 10% to take dilution into account) are correlated but are not equivalent. The numCTAD+10% underestimate numEDTA significantly. The systematic bias is removed if we increase by 17% numCTAD. The factor of correction is stable over a period of 3 hours.

  2. Performance evaluation of platelet counting by novel fluorescent dye staining in the XN-series automated hematology analyzers.

    PubMed

    Tanaka, Yuzo; Tanaka, Yumiko; Gondo, Kazumi; Maruki, Yoshiko; Kondo, Tamiaki; Asai, Satomi; Matsushita, Hiromichi; Miyachi, Hayato

    2014-09-01

    Conventional automated hematology analyzers have limitations in platelet measurements such as poor accuracy and precision in the low count range and interference by nonplatelet particles. In order to improve it, the newly developed XN-Series automated hematology analyzers (Sysmex Corporation, Kobe, Japan) have been installed with a new dedicated channel for platelet analysis (PLT-F), which is based on a fluorescence flow cytometry method with uses of a novel fluorescent dye specifically staining platelets. We evaluated the basic performance of this new PLT-F channel. Basic performance of the PLT-F channel in within-run reproducibility and assay linearity was studied using standard methods. Correlation was studied between PLT-F and a conventional automated hematology analyzer (XE-2100) and immunoplatelet analysis using anti-CD61 monoclonal antibody (Cell-Dyn Sapphire; Abbott Laboratories). The assay interference by nonplatelet particles such as fragmented red and white blood cells was evaluated by using clinical samples, respectively, from burn injury and acute leukemia. Basic performance of the PLT-F platelet counting was satisfactory in within-run reproducibility, linearity and correlation with the conventional analyzer. The correlation was satisfactory also with the immunoplatelet analysis, even for samples from a patient with burn injury, and those with white blood cell fragments displayed, platelet abnormal flag and low platelet counts (<50 × 10(9)/l). The platelet counting performance of the PLT-F channel of the XN Series had improved accuracy and precision in the low range and in abnormal samples, avoiding the interference by nonplatelet particles. © 2014 Wiley Periodicals, Inc.

  3. Evaluation of super-resolution performance of the K2 electron-counting camera using 2D crystals of aquaporin-0.

    PubMed

    Chiu, Po-Lin; Li, Xueming; Li, Zongli; Beckett, Brian; Brilot, Axel F; Grigorieff, Nikolaus; Agard, David A; Cheng, Yifan; Walz, Thomas

    2015-11-01

    The K2 Summit camera was initially the only commercially available direct electron detection camera that was optimized for high-speed counting of primary electrons and was also the only one that implemented centroiding so that the resolution of the camera can be extended beyond the Nyquist limit set by the physical pixel size. In this study, we used well-characterized two-dimensional crystals of the membrane protein aquaporin-0 to characterize the performance of the camera below and beyond the physical Nyquist limit and to measure the influence of electron dose rate on image amplitudes and phases.

  4. Evaluation of super-resolution performance of the K2 electron-counting camera using 2D crystals of aquaporin-0

    PubMed Central

    Chiu, Po-Lin; Li, Xueming; Li, Zongli; Beckett, Brian; Brilot, Axel F.; Grigorieff, Nikolaus; Agard, David A.; Cheng, Yifan; Walz, Thomas

    2015-01-01

    The K2 Summit camera was initially the only commercially available direct electron detection camera that was optimized for high-speed counting of primary electrons and was also the only one that implemented centroiding so that the resolution of the camera can be extended beyond the Nyquist limit set by the physical pixel size. In this study, we used well-characterized two-dimensional crystals of the membrane protein aquaporin-0 to characterize the performance of the camera below and beyond the physical Nyquist limit and to measure the influence of electron dose rate on image amplitudes and phases. PMID:26318383

  5. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Performance Management § 9701.409 Rating and rewarding... management system must establish a single summary rating level of unacceptable performance, a summary rating... successful performance. (2) For employees in an Entry/Developmental band, the DHS performance management...

  6. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... management system must establish a single summary rating level of unacceptable performance, a summary rating level of fully successful performance (or equivalent), and at least one summary rating level above fully successful performance. (2) For employees in an Entry/Developmental band, the DHS performance...

  7. The utility of erythrocyte sedimentation rate values and white blood cell counts after spinal deformity surgery in the early (≤3 months) post-operative period.

    PubMed

    Kuhn, Margaret G; Lenke, Lawrence G; Bridwell, Keith H; O'Donnell, June C; Luhmann, Scott J

    2012-03-01

    The erythrocyte sedimentation rate (ESR) and white blood cell (WBC) count are frequently obtained in the work-up of post-operative fever. However, their diagnostic utility depends upon comparison with normative peri-operative trends which have not yet been described. The purpose of this study is to define a range of erythrocyte sedimentation rates and white blood cell counts following spinal instrumentation and fusion in non-infected patients. Seventy-five patients underwent spinal instrumentation and fusion. The erythrocyte sedimentation rate and white blood cell count were recorded pre-operatively, at 3 and 7 days post-operatively, and at 1 and 3 months post-operatively. Both erythrocyte sedimentation rate and white blood cell count trends demonstrated an early peak, followed by a gradual return to normal. Peak erythrocyte sedimentation rates occurred within the first week post-operatively in 98% of patients. Peak white blood cell counts occurred with the first week in 85% of patients. In the absence of infection, the erythrocyte sedimentation rate was abnormally elevated in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively. The white blood cell count was abnormally elevated in only 6% of patients at 1 month post-operatively. Longer surgical time was associated with elevated white cell count at 1 week post-operatively. The fusion of more vertebral levels had a negative relationship with elevated erythrocyte sedimentation rate at 1 week post-operatively. The anterior surgical approach was associated with significantly lower erythrocyte sedimentation rate at 1 month post-operatively and with lower white cell count at 1 week post-operatively. In non-infected spinal fusion surgeries, erythrocyte sedimentation rates are in the abnormal range in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively, suggesting that the erythrocyte sedimentation rate is of limited diagnostic value in the early post

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

    PubMed

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

    2014-11-01

    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.

  9. 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.

  10. 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.

  11. Clinical features and outcome of T-lineage acute lymphoblastic leukemia in adults: a low initial white blood cell count, as well as a high count predict decreased survival rates.

    PubMed

    Yanada, Masamitsu; Jinnai, Itsuro; Takeuchi, Jin; Ueda, Takanori; Miyawaki, Shuichi; Tsuzuki, Motohiro; Hatta, Yoshihiro; Usui, Noriko; Wada, Hideho; Morii, Takeshi; Matsuda, Mitsuhiro; Kiyoi, Hitoshi; Okada, Masaya; Honda, Sumihisa; Miyazaki, Yasushi; Ohno, Ryuzo; Naoe, Tomoki

    2007-07-01

    Although biological and clinical features differ between B-lineage acute lymphoblastic leukemia (ALL) and T-lineage ALL (T-ALL), there have been few reports that focused on the prognosis for T-ALL in adults, primarily due to its rarity. Here, we studied the long-term outcomes and prognostic factors specific for adult T-ALL by combining patient data from the three prospective trials conducted by the Japan Adult Leukemia Study Group (JALSG). Among 559 patients whose immunophenotypes could be evaluated, 87 (15.6%) were identified as T-ALL. Of them, 66 patients (75.8%) achieved complete remission, and relapse occurred in 41 patients. With a median follow-up for surviving patients of 7.5 years, the probability of overall survival was 35.0% at 5 years. Risk factor analysis revealed that serum albumin levels, initial white blood cell (WBC) counts, and age had independent values for predicting survival. For WBC, not only the high-count group (50 x 10(9)l(-1) or higher), but also the low-count group (less than 3 x 10(9)l(-1)) showed a significantly lower survival rates than the intermediate-count group (p=0.0055 and 0.0037, respectively). Although our findings need confirmation, these results will be helpful in the identification of prognostically distinct subgroups within adult T-ALL.

  12. Analytic performance of the iQ200 automated urine microscopy analyzer and comparison with manual counts using Fuchs-Rosenthal cell chambers.

    PubMed

    Wah, David T; Wises, Porntip K; Butch, Anthony W

    2005-02-01

    Automated instruments that can examine urine for cells and particles have reduced the need for labor-intensive manual microscopy. We evaluated the performance of the Iris iQ200 Automated Urine Microscopy Analyzer (Iris Diagnostics, Chatsworth, CA) and compared results with manual cell and particle counts using Fuchs-Rosenthal counting chambers. Within-run imprecision (coefficient of variation) of the iQ200 for urine samples ranged from 3.0% to 45% for RBC counts between 1,029 and 3 x 10(6) cells/L, 3.4% to 40% for WBC counts between 1,006 and 4 x 10(6) cells/L, and 8.9% to 35% for epithelial cell counts between 93 and 4 x 10(6) cells/L. Between-run imprecision was 3.3% at 1,017 x 10(6) cells/L and 19.2% at 28 x 10(6) cells/L. There was good agreement between the iQ200 and manual cell counts (r > or = 0.94); however; the iQ200 produced lower results based on slopes of 0.92 (RBC count), 0.81 (WBC count), and 0.94 (epithelial cell counts). The iQ200 has satisfactory performance and correlates well with manual cell counts. Most urine samples containing RBCs, WBCs, and epithelial cells can be reported without review of captured images.

  13. 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.; hide

    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.

  14. WE-FG-207A-04: Performance Characteristics of Photon-Counting Breast CT.

    PubMed

    Kalender, W

    2016-06-01

    Mammography-based screening has been a valuable imaging tool for the early detection of non-palpable lesions and has contributed to significant reduction in breast cancer associated mortality. However, the breast imaging community recognizes that mammography is not ideal, and in particular is inferior for women with dense breasts. Also, the 2-D projection of a 3-D organ results in tissue superposition contributing to false-positives. The sensitivity of mammography is breast-density dependent. Its sensitivity, especially in dense breasts, is low due to overlapping tissue and the fact that normal breast tissue, benign lesions and breast cancers all have similar "densities", making lesion detection more difficult. We ideally need 3-D imaging for imaging the 3-D breast. MRI is 3-D, whole breast ultrasound is 3-D, digital breast tomosynthesis is called 3-D but is really "pseudo 3-D" due to poor resolution along the depth-direction. Also, and importantly, we need to be able to administer intravenous contrast agents for optimal imaging, similar to other organ systems in the body. Dedicated breast CT allows for 3-D imaging of the uncompressed breast. In current designs, the patient is positioned prone on the table and the breast is pendant through an aperture and the scan takes approximately 10 seconds [O'Connell et al., AJR 195: 496-509, 2010]. Almost on the heels of the invention of CT itself, work began on the development of dedicated breast CT. These early breast CT systems were used in clinical trials and the results from comparative performance evaluation of breast CT and mammography for 1625 subjects were reported in 1980 [Chang et al., Cancer 46: 939-46, 1980]. However, the technological limitations at that time stymied clinical translation for decades. Subsequent to the landmark article in 2001 [Boone et al., Radiology 221: 657-67, 2001] that demonstrated the potential feasibility in terms of radiation dose, multiple research groups are actively investigating

  15. 5 CFR 9901.412 - Rating and rewarding performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Rating and rewarding performance. 9901... NATIONAL SECURITY PERSONNEL SYSTEM (NSPS) Performance Management § 9901.412 Rating and rewarding performance. (a) Forced distribution of ratings (setting pre-established limits for the percentage or number...

  16. 5 CFR 930.206 - Performance rating and awards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Performance rating and awards. 930.206 Section 930.206 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... Judge Program § 930.206 Performance rating and awards. (a) An agency may not rate the job performance of...

  17. 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.

  18. Spectral performance of a whole-body research photon counting detector CT: quantitative accuracy in derived image sets

    NASA Astrophysics Data System (ADS)

    Leng, Shuai; Zhou, Wei; Yu, Zhicong; Halaweish, Ahmed; Krauss, Bernhard; Schmidt, Bernhard; Yu, Lifeng; Kappler, Steffen; McCollough, Cynthia

    2017-09-01

    Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI). Vials containing iodine with five known concentrations were scanned on the PCCT scanner after being placed in phantoms representing the attenuation of different size patients. For comparison, the same vials and phantoms were also scanned on 2nd and 3rd generation dual-source, dual-energy scanners. After material decomposition, iodine maps were generated, from which iodine concentration was measured for each vial and phantom size and compared with the known concentration. Additionally, VMIs were generated and CT number accuracy was compared to the reference standard, which was calculated based on known iodine concentration and attenuation coefficients at each keV obtained from the U.S. National Institute of Standards and Technology (NIST). Results showed accurate iodine quantification (root mean square error of 0.5 mgI/cc) and accurate CT number of VMIs (percentage error of 8.9%) using the PCCT scanner. The overall performance of the PCCT scanner, in terms of iodine quantification and VMI CT number accuracy, was comparable to that of EID-based dual-source, dual-energy scanners.

  19. Spectral Performance of a Whole-Body Research Photon Counting Detector CT: Quantitative Accuracy in Derived Image Sets

    PubMed Central

    Leng, Shuai; Zhou, Wei; Yu, Zhicong; Halaweish, Ahmed; Krauss, Bernhard; Schmidt, Bernhard; Yu, Lifeng; Kappler, Steffen; McCollough, Cynthia

    2017-01-01

    Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI). Vials containing iodine with 5 known concentrations were scanned on the PCCT scanner after being placed in phantoms representing the attenuation of different size patients. For comparison, the same vials and phantoms were also scanned on 2nd and 3rd generation dual-source, dual-energy (DSDE) scanners. After material decomposition, iodine maps were generated, from which iodine concentration was measured for each vial and phantom size and compared with the known concentration. Additionally, VMIs were generated and CT number accuracy was compared to the reference standard, which was calculated based on known iodine concentration and attenuation coefficients at each keV obtained from the U.S. National Institute of Standards and Technology. Results showed accurate iodine quantification (root mean square error of 0.5 mgI/cc) and accurate CT number of VMIs (percentage error of 8.9%) using the PCCT scanner. The overall performance of the PCCT scanner, in terms of iodine quantification and VMI CT number accuracy, was comparable to that of EID-based dual-source, dual-energy scanners. PMID:28726669

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

    PubMed

    Silva, H G; Lopes, I

    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.

  1. 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.

  2. WBC count

    MedlinePlus

    Leukocyte count; White blood cell count ... blood is 4,500 to 11,000 white blood cells per microliter (mcL) or 4.5 to 11. ... LOW WHITE BLOOD CELL (WBC) COUNT A low number of WBCs is called leukopenia. A WBC count below 4500 is below normal ...

  3. Photon counting performance measurements of transfer electron InGaAsP photocathode hybrid photomultiplier tubes at 1064 nm wavelength

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoli; Krainak, Michael A.; Hasselbrack, William B.; La Rue, Ross A.

    2007-05-01

    We report the test results of a hybrid photomultiplier tube (HPMT) with a transfer electron (TE) InGaAsP photocathode and GaAs Schottky avalanche photodiode (APD) anode. Unlike Geiger mode InGaAsP APDs, these HPMTs (also known as intensified photodiode (IPD), vacuum APD, or hybrid photodetector) operate in linear mode without the need for quenching and gating. Their greatest advantages are wide dynamic range, high speed, large photosensitive area, and potential for photon counting and analog detection dual mode operation. The photon detection efficiency we measured was 25% at 1064 nm wavelength with a dark count rate of 60,000/s at -22 degrees Celsius. The output pulse width in response to a single photon detection is about 0.9 ns. The maximum count rate was 90 Mcts/s and was limited solely by the speed of the discriminator used in the measurement (10 ns dead time). The spectral response of these devices extended from 900 to 1300 nm. We also measured the HPMT response to 60 ps laser pulses. The average output pulse amplitude increased monotonically with the input pulse energy, which suggested that we can resolve photon number in an incident pulse. The jitter of the HPMT output was found to be about 0.5 ns standard deviation and depended on bias voltage applied to the TE photocathode. To our knowledge, these HPMTs are the most sensitive non gating photon detectors at 1064 nm wavelength, and they will have many applications in laser altimeters, atmospheric lidars, and free space laser communication systems.

  4. Spectral Performance of Photon Counting Pixel Detector Using Attenuation Spectra for Test Samples

    SciTech Connect

    Esebamen, Omeime Xerviar Ohi; Norlin, Boerje; Thungstroem, Goeran

    2010-01-05

    When a material is placed along the path of an X-ray beam using a broad range of energy X-ray source, the energy dependence of the attenuation for the X-ray photons will be substantially dissimilar for different materials. The process at which X-ray radiation loses its penetrating strength as it travels through a material will be significantly larger for photons with energy above k-edge energy of that material than for those with slightly lower energy. Hence energy resolved X-ray imaging can be used to achieve colour images revealing the material content of the test sample. The attenuation of the spectrum done by scanning an energy window through the spectrum was measured for a number of samples of different materials. The test samples include Sn, Gd and I with K-edge energy at 29 keV, 50 keV and 33 keV, respectively, using a Feinfocus microfocus X-ray source (FTP-105.02) with Medipix2 photon counting chip.

  5. Mindray BC-6800 body fluid mode, performance of nucleated cells, and differential count in ascitic and pleural fluids.

    PubMed

    Buoro, S; Mecca, T; Azzarà, G; Seghezzi, M; Candiago, E; Gianatti, A; Crippa, A; La Gioia, A

    2016-02-01

    An accurate and rapid analysis of cells in body fluids (BFs) is important for diagnosis and follow-up in many pathological conditions. We evaluated the analytical performance of the module BF Mindray BC-6800 (BC-6800-BF) for cytometric analysis of ascitic and pleural fluids. A total of 99 ascitic and 45 pleural samples were collected and assessed with BC-6800-BF and optical microscopy. This study also includes the evaluation of limit blank (LoB), limit detection (LoD), limit quantitation, (LoQ), carryover, linearity, and diagnostic concordance between the two methods. For TC-BF, LoB was 1 × 10(6) cells/L, LoD was 3 × 10(6) cells/L, and LoQ was 4 × 10(6) cells/L. Linearity was excellent (r(2) = 0.99) and carryover was negligible. TC-BF performed with the two methods showed Pearson's correlation of 0.99 (P < 0.0001), Passing-Bablok regression y = 1.04x - 1.17, and bias 33.7 cells. In ascitic fluids, polymorphonuclear cells (PMN) showed an area under curve (AUC) of 0.98 (P < 0.0001). In pleural fluids, mononuclear cells (MN) and PMN % displayed an AUC of 0.79 (P < 0.0001) and 0.93 (P < 0.0001), respectively. BC-6800-BF in ascitic and pleural fluids offers rapid and accurate cell and differential counts in clinically relevant concentration ranges. The use of BC-6800-BF may allow to replace routine optical counting, except for samples displaying abnormal cell counts or abnormal DIFF scattergram. © 2015 John Wiley & Sons Ltd.

  6. 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.

  7. 5 CFR 9901.412 - Rating and rewarding performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and sustained change in the employee's performance since the last rating of record. (c) The... prepare a performance assessment (e.g., close-out assessment) for the purpose of providing input on an employee's performance to a new supervisor. Such an assessment is not a rating of record (recommended...

  8. Development of liquid scintillation based 4πβ(LS)-γ coincidence counting system and demonstration of its performance by standardization of ⁶⁰Co.

    PubMed

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

    2013-02-01

    A single-vial, single-PMT 4πβ(LS)-γ coincidence counting system has been developed at the Radiation Safety Systems Division, BARC. It has advantages of simple sample preparation, higher counting efficiency and the absence of self absorption over the conventional proportional counter based 4πβ(PC)-γ coincidence counting system. The performance of the system is demonstrated by standardizing a (60)Co solution using the 4πβ(LS)-γ coincidence counting system, 4πβ(PC)-γ coincidence counting system and CIEMAT/NIST method and comparing the results obtained by each method. The detection efficiency of liquid scintillation counter of the 4πβ(LS)-γ coincidence counting system was varied by color quenching, by chemical quenching and by varying the bias voltage applied to the LSC PMT. For the proportional counter based 4πβ(PC)-γ coincidence counting system the detection efficiency was varied by source self absorption. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, the 4πβ(PC)-γ coincidence counting system and the CIEMAT/NIST method are comparable within the uncertainty limits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Performance of single photon-counting X-ray charge coupled devices

    NASA Technical Reports Server (NTRS)

    Riegler, G. R.; Stern, R. A.; Liewer, K.; Vescelus, F.; Nousek, J. A.; Garmire, G. P.

    1981-01-01

    Results of intial performance tests on X-ray sensing properties of charge-coupled devices (CCDs) are presented. CCDs have demonstrated excellent spatial resolution and good spectral resolution, superior to that of non-imaging proportional counters.

  10. The relationship between NHS performance indicators and suicide rates.

    PubMed

    Zhinchin, Galina; Shah, Ajit

    2013-10-01

    As mental health services have an important role in prevention of suicides, the relationship between Care Quality Commission performance ratings of mental health trusts and the local suicide rates were examined with the null hypothesis that there will be no relationship between them. Data on suicide rates for men and women aged 16-65 for each district covered by a mental health trust were ascertained from the Office of National Statistics for the year 2009. Data on performance ratings of mental health trusts for the same year were obtained from the Care Quality Commission Report. There was no significant relationship between suicide rates in the districts covered by 60 mental health trusts in England and Wales and their performance ratings. The negative findings suggest that the performance rating of mental health trusts do not influence local suicide rates.

  11. The Effects of Slow Frame Rates on Human Performance

    DTIC Science & Technology

    2006-06-01

    The Effects of Slow Frame Rates on Human Performance by Jennifer E. Thropp and Jessie Y.C. Chen ARL-TR-3813 June 2006...21005-5425 ARL-TR-3813 June 2006 The Effects of Slow Frame Rates on Human Performance Jennifer E. Thropp University of Central Florida...AND SUBTITLE The Effects of Slow Frame Rates on Human Performance 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 62716AH70 5e. TASK

  12. The evaluation methods of sampling rate performance in GNSS receiver

    NASA Astrophysics Data System (ADS)

    Ke, Ting; Hu, Xiulin; Liu, Yuqi; Ran, Yihang

    2009-12-01

    This paper investigates into the performance of sampling rate on time discrimination of PRN code in GNSS, proposes an innovative performance evaluation criterion for actual time discrimination of noncommensurate sampling technique, and then develops an algorithm to quickly obtain this criterion. Computer simulation verification guarantees the correctness of the proposed fast algorithm. The proposed algorithm can be adopted in all PRN code ranging based applications to choose the "better" sampling rate, which could achieve better time discrimination performance with lower sampling rate.

  13. Improving the performance of ultrafast microchannel-plate photomultipliers in time-correlated photon counting by pulse pre-shaping

    SciTech Connect

    Cova, S.; Ripamonti, G. )

    1990-03-01

    With ultrafast microchannel-plate (MCP) photomultipliers that produce subnanosecond pulses, the commercially available circuit modules do not provide a correct constant-fraction trigger (CFT) operation. This has a detrimental effect on the resolution obtained in time-correlated photon counting experiments. In order to circumvent this CFT limitation and better exploit the ultrafast MCP performance, a simple pulse-shaping filter has been devised and experimented with. The filter can be interposed between the MCP output and the input of any commercial CFT module, without modifying the latter. The benefit of the filter is confirmed by the experimental results. With MCP samples that produced awkward resolution curves with satellite peaks and other irregular features, the introduction of the filter regularized and narrowed the curve. Also with a setup having fairly good performance, the introduction of the filter was advantageous: the full width at half maximum (FWHM) resolution improved from 75 to 55 ps.

  14. 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

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

    PubMed

    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

    2016-02-21

    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

  16. 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

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

    PubMed

    Zhu, Yazhong; Li, Shunyi; 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/m(3). The maximum elimination capacity of 36.0 g/(m(3) h) occurred at an inlet loading rate of 45.9 g/(m(3) 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. A Longitudinal Examination of Rater and Ratee Effects in Performance Ratings.

    ERIC Educational Resources Information Center

    Vance, Robert J.; And Others

    1983-01-01

    Investigated the consistency and loci of leniency, halo, and range restriction effects in performance ratings in a longitudinal study. Policy supervisors (N=90) rated 350 subordinates on five occasions. Concluded that reliable variance in mean ratings is partly attributable to ratees, but mainly introduced by raters. (JAC)

  3. Conductor and Ensemble Performance Expressivity and State Festival Ratings

    ERIC Educational Resources Information Center

    Price, Harry E.; Chang, E. Christina

    2005-01-01

    This study is the second in a series examining the relationship between conducting and ensemble performance. The purpose was to further examine the associations among conductor, ensemble performance expressivity, and festival ratings. Participants were asked to rate the expressivity of video-only conducting and parallel audio-only excerpts from a…

  4. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Rating and rewarding performance. 9701.409 Section 9701.409 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES... SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Performance Management § 9701.409 Rating and...

  5. 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.

  6. Emilio Segre' Observatory and expected time-variations in neutron monitor total and multiplicities counting rates caused by cosmic ray particle energy change in the periods of thunderstorms

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.

    In the first part of paper we give short description of the Israelo-Italian Emilio Segre' Observatory (33°18.3‧N, 35°47.2‧E, 2025 m above sea level, Rc=10.8 GV), established in June 1998. In the second part, on the basis of theoretical model (Dorman & Dorman 1995, 1999; Dorman et al. 1995) of atmospheric electric field effect in the neutron monitor total counting rate and counting rates of different neutron multiplicities, we calculate the expected cosmic ray time variations in the different channels of 6NM-64 neutron monitor of Emilio Segre' Observatory in the periods before and during thunderstorms. Our calculations show that one-minute data of 6NM-64 neutron monitor of Emilio Segre' Observatory and one minute data of EFS-1000 sensor of atmospheric electric field can be used for obtaining important information on atmospheric electric field space-time distribution.

  7. Race, Sex, and Performance Ratings in the Federal Service.

    ERIC Educational Resources Information Center

    Lewis, Gregory B.

    1997-01-01

    Analysis of a 1% sample of performance appraisals of federal employees of comparable education and experience (1990-95) found that women, especially whites, received higher ratings than white men at the same level. Minorities were more likely to receive a "fully successful" rating and less likely to receive an "outstanding" rating. (SK)

  8. 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.

  9. 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

  10. Performance of the PointCare NOW System for CD4 Counting in HIV Patients Based on Five Independent Evaluations

    PubMed Central

    Ding, Tao; Sitoe, Nadia E.; Westerman, Larry E.; Stokx, Jocelijn; Jani, Ilesh V.; Coetzee, Lindi M.; Scott, Lesley; De Weggheleire, Anja; Boel, Luc; Stevens, Wendy S.; Glencross, Deborah K.; Peter, Trevor F.

    2012-01-01

    Introduction Point-of-care (POC) CD4 testing can improve access to treatment by enabling decentralization and reducing patient loss-to-follow-up. As new POC CD4 technologies become available, their performance should be assessed before widespread deployment. This study reports the findings of five independent evaluations of the PointCare NOW CD4 system. Materials/Methods Evaluations were conducted in Southern Africa (Mozambique, South Africa) and North America (Canada, USA). 492 blood samples (55 from HIV-negative blood donors and 437 from HIV-infected patients, including 20 children aged between 12 and 59 months) were tested with both the PointCare NOW and reference flow cytometry instruments. Assessment of bias, precision and levels of clinical misclassification for absolute and percent CD4 count was conducted. Results PointCare NOW significantly overestimated CD4 absolute counts with a mean relative bias of +35.0%. Bias was greater in samples with CD4 counts below ≤350cells/µl (+51.3%) than in the CD4 >350cells/µl stratum (15.1%). Bias in CD4% had a similar trend with an overall relative mean bias of +25.6% and a larger bias for low CD4 stratum (+40.2%) than the higher CD4 stratum (+5.8%). Relative bias for CD4% in children was −6.8%. In terms of repeatability, PointCare NOW had a coefficient of variation of 11%. Using a threshold of 350cells/µl, only 47% of patients who qualified for antiretroviral therapy with reference CD4 testing, would have been eligible for treatment with PointCare NOW test results. This was 39% using a 200cells/µl threshold. Agreement with infant samples was higher, with 90% qualifying at a 25% eligibility threshold. Conclusion The performance of the PointCare NOW instrument for absolute and percent CD4 enumeration was inadequate for HIV clinical management in adults. In children, the small sample size was not large enough to draw a conclusion. This study also highlights the importance of independent evaluation of new diagnostic

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

    SciTech Connect

    Raynal, Ann Marie; William H. Hensley, Jr.; 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.

  12. Anarthria impairs subvocal counting.

    PubMed

    Cubelli, R; Nichelli, P; Pentore, R

    1993-12-01

    We studied subvocal counting in two pure anarthric patients. Analysis showed that they performed definitively worse than normal subjects free to articulate subvocally and their scores were in the lower bounds of the performances of subjects suppressing articulation. These results suggest that subvocal counting is impaired after anarthria.

  13. Analysis of low level radioactive metabolites in biological fluids using high-performance liquid chromatography with microplate scintillation counting: method validation and application.

    PubMed

    Zhu, Mingshe; Zhao, Weiping; Vazquez, Natasha; Mitroka, James G

    2005-09-01

    TopCount, a microplate scintillation counter (MSC), has been recently employed as an off-line liquid radiochromatographic detector for radioactive metabolite profile analysis. The present study was undertaken to validate TopCount for metabolite profiling with respect to sensitivity, accuracy, precision and radioactivity recovery. Matrix effects of various human samples on TopCount performance and capability of MSC for volatile metabolite analysis were also investigated. TopCount had a limit of detection (LOD) of 5 DPM and a limit of quantification (LOQ) of 15 DPM for [(14)C]-labeled compounds at a 10min counting time. It was two-fold more sensitive than a liquid scintillation counter (LSC), and 50-100-fold more sensitive than a radioactivity flow detector (RFD). TopCount had comparable accuracy and precision to RFD, and comparable precision to LSC for determining relative abundance of metabolites. Human liver microsome incubation (up to 1 mL), plasma (up to 1 mL), urine (up to 2 mL) and feces (up to 50mg) had no significant quenching effects on TopCount performance. Benzoic acid, a volatile metabolite, was detected by TopCount, but not by Microbeta counter after microplates were dried under vacuum. Radioactivity recovery in HPLC-MSC analysis was reliably determined using an LSC-based method. Examples of using HPLC-MSC for analysis of low levels of radioactive metabolites are presented, including determination of plasma metabolite profile, in vitro reactive metabolites trapped by [(3)H]glutathione, and metabolite concentrations in an enzyme kinetic experiment. The data from this study strongly suggest that HPLC in combination with TopCount is a viable alternative analytical tool for detection and quantification of low levels of radioactive metabolites in biological fluids.

  14. Association between Resting Heart Rate and Inflammatory Markers (White Blood Cell Count and High-Sensitivity C-Reactive Protein) in Healthy Korean People.

    PubMed

    Park, Woo-Chul; Seo, Inho; Kim, Shin-Hye; Lee, Yong-Jae; Ahn, Song Vogue

    2017-01-01

    Inflammation is an important underlying mechanism in the pathogenesis of atherosclerosis, and an elevated resting heart rate underlies the process of atherosclerotic plaque formation. We hypothesized an association between resting heart rate and subclinical inflammation. Resting heart rate was recorded at baseline in the KoGES-ARIRANG (Korean Genome and Epidemiology Study on Atherosclerosis Risk of Rural Areas in the Korean General Population) cohort study, and was then divided into quartiles. Subclinical inflammation was measured by white blood cell count and high-sensitivity C-reactive protein. We used progressively adjusted regression models with terms for muscle mass, body fat proportion, and adiponectin in the fully adjusted models. We examined inflammatory markers as both continuous and categorical variables, using the clinical cut point of the highest quartile of white blood cell count (≥7,900/mm(3)) and ≥3 mg/dL for high-sensitivity C-reactive protein. Participants had a mean age of 56.3±8.1 years and a mean resting heart rate of 71.4±10.7 beats/min; 39.1% were men. In a fully adjusted model, an increased resting heart rate was significantly associated with a higher white blood cell count and higher levels of high-sensitivity C-reactive protein in both continuous (P for trend <0.001) and categorical (P for trend <0.001) models. An increased resting heart rate is associated with a higher level of subclinical inflammation among healthy Korean people.

  15. Hospital performance measures and 30-day readmission rates.

    PubMed

    Stefan, Mihaela S; Pekow, Penelope S; Nsa, Wato; Priya, Aruna; Miller, Lauren E; Bratzler, Dale W; Rothberg, Michael B; Goldberg, Robert J; Baus, Kristie; Lindenauer, Peter K

    2013-03-01

    Lowering hospital readmission rates has become a primary target for the Centers for Medicare & Medicaid Services, but studies of the relationship between adherence to the recommended hospital care processes and readmission rates have provided inconsistent and inconclusive results. To examine the association between hospital performance on Medicare's Hospital Compare process quality measures and 30-day readmission rates for patients with acute myocardial infarction (AMI), heart failure and pneumonia, and for those undergoing major surgery. We assessed hospital performance on process measures using the 2007 Hospital Inpatient Quality Reporting Program. The process measures for each condition were aggregated in two separate measures: Overall Measure (OM) and Appropriate Care Measure (ACM) scores. Readmission rates were calculated using Medicare claims. Risk-standardized 30-day all-cause readmission rate was calculated as the ratio of predicted to expected rate standardized by the overall mean readmission rate. We calculated predicted readmission rate using hierarchical generalized linear models and adjusting for patient-level factors. Among patients aged ≥ 66 years, the median OM score ranged from 79.4 % for abdominal surgery to 95.7 % for AMI, and the median ACM scores ranged from 45.8 % for abdominal surgery to 87.9 % for AMI. We observed a statistically significant, but weak, correlation between performance scores and readmission rates for pneumonia (correlation coefficient R = 0.07), AMI (R = 0.10), and orthopedic surgery (R = 0.06). The difference in the mean readmission rate between hospitals in the 1st and 4th quartiles of process measure performance was statistically significant only for AMI (0.25 percentage points) and pneumonia (0.31 percentage points). Performance on process measures explained less than 1 % of hospital-level variation in readmission rates. Hospitals with greater adherence to recommended care processes did not achieve

  16. High-performance integrated pick-up circuit for SPAD arrays in time-correlated single photon counting

    NASA Astrophysics Data System (ADS)

    Acconcia, Giulia; Cominelli, Alessandro; Peronio, Pietro; Rech, Ivan; Ghioni, Massimo

    2017-05-01

    The analysis of optical signals by means of Single Photon Avalanche Diodes (SPADs) has been subject to a widespread interest in recent years. The development of multichannel high-performance Time Correlated Single Photon Counting (TCSPC) acquisition systems has undergone a fast trend. Concerning the detector performance, best in class results have been obtained resorting to custom technologies leading also to a strong dependence of the detector timing jitter from the threshold used to determine the onset of the photogenerated current flow. In this scenario, the avalanche current pick-up circuit plays a key role in determining the timing performance of the TCSPC acquisition system, especially with a large array of SPAD detectors because of electrical crosstalk issues. We developed a new current pick-up circuit based on a transimpedance amplifier structure able to extract the timing information from a 50-μm-diameter custom technology SPAD with a state-of-art timing jitter as low as 32ps and suitable to be exploited with SPAD arrays. In this paper we discuss the key features of this structure and we present a new version of the pick-up circuit that also provides quenching capabilities in order to minimize the number of interconnections required, an aspect that becomes more and more crucial in densely integrated systems.

  17. Effects of Rating Purpose and Rater Self-Esteem on Performance Ratings.

    DTIC Science & Technology

    1983-03-01

    MUlIGUR 83-3 Z 11l 4. TITLE (and Subtitle) a. TYPE Or REPORT A PVfOO COVERED Effects of Rating Purpose and Rater Self - Esteem Interim I on...rnmbee) U..N1’ MiAY 27 093 Performance Ratings, Rating Purpose, Self - Esteem 26, ASTRACT (Continueo an revere* side of necessay aid Identify by block gmN...The influences of intended rating purpose (administrative vs. employee counseling) and rater self - esteem on ratings of employee performance were

  18. Emotions, heart rate and performance in archery. A case study.

    PubMed

    Robazza, C; Bortoli, L; Nougier, V

    1999-06-01

    A case study of an elite female archer was conducted to gain insight into individual psychophysical reactions accompanying an athletic event, and to test predictions of pre-performance emotions effects upon performance. Good performance was expected when the actual pre-performance emotions resembled the recalled optimal emotion pattern. Conversely, poor performance was expected when the actual pre-performance emotions paralleled the recalled ineffective emotion pattern. the investigation comprised individual emotion profiling, emotions and heart rate monitoring, final interview and performance evaluation. The research was accomplished during the 1996 European Archery Championships, one of the most important international archery competitions. An 18-year-old female athlete of the Italian archery national team. Because of the exploratory nature of the study, no intervention was implemented. Emotion profiling was carried out using an idiographic approach based on recalled optimal and poor performances, according to the Individual Zones of Optimal Functioning (IZOF) model. Emotions, heart rate, and performance were monitored across the five days of practice and competition. Individual pre-performance optimal emotion pattern, heart rate deceleration during shooting, consistent shooting scores were revealed throughout practice and competition. The good performance predicted on the basis of pre-performance emotion assessments was met and was confirmed by the archer's interpretation.

  19. Combined prognostic utility of white blood cell count, plasma glucose, and glomerular filtration rate in patients undergoing primary stent placement for acute myocardial infarction.

    PubMed

    Kosuge, Masami; Kimura, Kazuo; Morita, Satoshi; Kojima, Sunao; Sakamoto, Tomohiro; Ishihara, Masaharu; Asada, Yujiro; Tei, Chuwa; Miyazaki, Shunichi; Sonoda, Masahiro; Tsuchihashi, Kazufumi; Yamagishi, Masakazu; Shirai, Mutsunori; Hiraoka, Hisatoyo; Honda, Takashi; Ogata, Yasuhiro; Ogawa, Hisao

    2009-02-01

    Although high white blood cell (WBC) count and plasma glucose (PG) and low glomerular filtration rate (GFR) on admission have been associated with poor outcomes after acute myocardial infarction (AMI), the combined prognostic utility of these 3 variables was unclear. The association of WBC count, PG, and GFR on admission to in-hospital outcomes was examined in 2,633 patients who underwent primary stent placement for ST-segment elevation AMI within 48 hours after symptom onset. In-hospital mortality progressively increased as the number of the variables of high WBC count (> or =11,120/microl; upper tertile), high PG (> or =10.4 mmol/L; upper tertile), and low GFR (< or =60 ml/min/1.73 m(2); lower tertile) increased. Patients with all 3 variables had a strikingly higher in-hospital mortality rate (25.9%). After adjusting for baseline characteristics, multivariate analysis showed that compared with patients who had none of these variables, odds ratios for in-hospital mortality were 1.63 (95% confidence interval [CI] 0.88 to 3.03, p = 0.12) in patients with only 1 variable, 2.33 (95% CI 1.28 to 3.96, p = 0.047) in those with 2 variables, and 6.16 (95% CI 2.98 to 12.6, p <0.001) in those with all 3 variables. In conclusion, combined evaluation of WBC count, PG, and GFR on admission was a simple and useful method for the early prediction of risk of in-hospital death in patients undergoing primary stent placement for ST-segment elevation AMI.

  20. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....409 Section 9701.409 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Performance Management § 9701.409 Rating and...

  1. Enhancing the performance of a point-of-care CD4+ T-cell counting microchip through monocyte depletion for HIV/AIDS diagnostics.

    PubMed

    Cheng, Xuanhong; Gupta, Amit; Chen, Chihchen; Tompkins, Ronald G; Rodriguez, William; Toner, Mehmet

    2009-05-21

    CD4+ T cell counts are important tests used to stage HIV-positive patients, enabling clinicians to make informed antiretroviral treatment decisions and to monitor the therapeutic outcomes. However, state-of-the-art CD4 counting methods based on flow cytometry are not applicable in resource-limited settings, due to their high cost and technical requirements. In previous work, we reported the development of a cell isolation microchip that can be used at the point of care for CD4 counts. In that microfluidic chip, CD4+ T cells were separated from 10 microL of whole blood, and enumerated via either light microscopy or impedance sensing. The microchip counts matched flow cytometry results in the intermediate CD4 count range, between 200-800 cells/microL, but displayed a positive bias at absolute CD4 counts below 200 cells/microL, due largely to monocyte contamination. To enhance the performance in the low CD4 count range, we report here an improved design of a two-stage microfluidic device to deplete monocytes from whole blood, followed by CD4+ T cell capture. Using the double-stage device combined with a high viscosity rinsing solution, we obtained microchip CD4 counts comparable to flow cytometry results in the full clinically relevant range. In addition to CD4 counting, the strategy of contaminant depletion prior to target cell isolation can be easily adapted to immunoaffinity capture of other cell types that lack a unique surface marker from a complex biological fluid.

  2. 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.…

  3. [Relationship between white blood cell count, neutrophils ratio and erythrocyte sedimentation rate and short clinical outcomes among patients with acute ischemic stroke at hospital admission].

    PubMed

    Ye, Jia-kai; Zhang, Jin-tao; Kong, Yan; Xu, Tan; Zou, Ting-ting; Zhang, Yong-hong; Zhang, Shao-yan

    2012-09-01

    To investigate the relationship between white blood cell count, neutrophils ratio and erythrocyte sedimentation rate and short outcomes among patients with acute ischemic stroke at admission to the hospital. A total of 2675 acute ischemic stroke patients were included in this study. Data on demographic characteristics, life style, history of disease, white blood cell count (WBC), neutrophils ratio (NEUR), erythrocyte sedimentation rate (ESR) and clinical outcomes were collected for all the participants. Poor clinical outcome was defined as neurologic deficiency (NIHSS ≥ 5) at discharge or death during hospitalization. White blood cell count, neutrophils ratio and erythrocyte sedimentation rate were higher in patients with poor outcome than in those without clinical outcome. According to the quartile range, WBC, NEUR and ESR were divided into four levels at admission. After adjustment for multivariate, compared with WBC ≤ 5.6× 10(9)/L, the odds ratio (95% confidence intervals) of poor outcome with ≥ 8.7×10(9)/L was 1.883 (1.306 - 2.716). When compared with NEUR ≤ 0.56, the odds ratio (95% confidence intervals) of poor outcome with 0.57 - 0.64 and with ≥ 0.74 were 1.572 (1.002 - 2.466) and 2.577 (1.698 - 3.910), respectively. When compared with ESR ≤ 4 mm/h, the odds ratio (95% confidence intervals) of poor outcome with ≥ 17 mm/h was 2.426 (1.233 - 4.776). Elevated WBC count and NEUR at admission were significantly and positively associated with poor clinical outcomes among patients with acute ischemic stroke (trend test P < 0.05). Elevated ESR was not significantly or positively associated with poor clinical outcomes among patients with acute ischemic stroke (trend test P > 0.05). There appeared associations between WBC, NEUR, ESR and poor outcome among patients with acute ischemic stroke at admission to the hospital. Both elevated WBC count and NEUR showed significantly positive association with poor clinical outcomes among patients with acute

  4. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    NASA Astrophysics Data System (ADS)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  6. 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…

  7. A problem-oriented approach to resident performance ratings.

    PubMed

    Williams, Reed G; Mellinger, John D; Dunnington, Gary L

    2016-10-01

    Global, end-of-rotation evaluations are often difficult to interpret due to their high level of abstraction (eg, excellent, good, poor) and the bias toward high ratings. This study documents the utility of and measurement characteristics of serious problem items, an alternative item format. This report is based on 4,234 faculty performance ratings for 105 general surgery residents. Faculty members reported whether each resident had a serious problem for each of 8 areas of clinical performance and 6 areas of professional behavior. A total of 263 serious problems were reported. The performance category with the most total serious problems noted was knowledge and that with the least problems noted was relations with patients and family members. Seven residents accounted for 86.9% of all serious problem reports. Each resident had serious problems in multiple performance areas. Problems were reported most frequently in knowledge, management, technical/procedural skills, ability to assume responsibility within level of competence, and problem identification. Citations of these serious problems were most common in year 3. Traditional ratings of global performance were not an adequate means for identifying residents with serious performance problems. Serious problem ratings can communicate faculty concerns about residents more directly and can be used as a complement to conventional global rating scales without substantially increasing faculty workload. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. The new X-ray mapping: X-ray spectrum imaging above 100 kHz output count rate with the silicon drift detector.

    PubMed

    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 MnKalpha). 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 x 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.Note: The Siegbahn notation for characteristic X-rays is commonly used in the field of electron beam X-ray spectrometry and will be used in this article. The equivalent IUPAC notation is indicated in parentheses at the first use. In this article, the following arbitrary definitions will be used when referring to concentration (C) ranges: major: C > 0.1 (10 wt%), minor: 0.01

  9. CD4 cell count and viral load-specific rates of AIDS, non-AIDS and deaths according to current antiretroviral use.

    PubMed

    Mocroft, Amanda; Phillips, Andrew N; Gatell, Jose; Horban, Andrej; Ledergerber, Bruno; Zilmer, Kai; Jevtovic, Djordje; Maltez, Fernando; Podlekareva, Daria; Lundgren, Jens D

    2013-03-27

    CD4 cell count and viral loads are used in clinical trials as surrogate endpoints for assessing efficacy of newly available antiretrovirals. If antiretrovirals act through other pathways or increase the risk of disease this would not be identified prior to licensing. The aim of this study was to investigate the CD4 cell count and viral load-specific rates of fatal and nonfatal AIDS and non-AIDS events according to current antiretrovirals. Poisson regression was used to compare overall events (fatal or nonfatal AIDS, non-AIDS or death), AIDS events (fatal and nonfatal) or non-AIDS events (fatal or nonfatal) for specific nucleoside pairs and third drugs used with more than 1000 person-years of follow-up (PYFU) after 1 January 2001. Nine thousand, eight hundred and one patients contributed 42372.5 PYFU, during which 1203 (437 AIDS and 766 non-AIDS) events occurred. After adjustment, there was weak evidence of a difference in the overall events rates between nucleoside pairs (global P-value = 0.084), and third drugs (global P-value = 0.031). As compared to zidovudine/lamivudine, patients taking abacavir/lamivudine [adjusted incidence rate ratio (aIRR) 1.22; 95% CI 0.99-1.49] and abacavir and one other nucleoside [aIRR 1.51; 95% CI 1.14-2.02] had an increased incidence of overall events. Comparing the third drugs, those taking unboosted atazanavir had an increased incidence of overall events compared with those taking efavirenz (aIRR 1.46; 95% CI 1.09-1.95). There was little evidence of substantial differences between antiretrovirals in the incidence of clinical disease for a given CD4 cell count or viral load, suggesting there are unlikely to be major unidentified adverse effects of specific antiretrovirals.

  10. Pulse pileup statistics for energy discriminating photon counting x-ray detectors.

    PubMed

    Wang, Adam S; Harrison, Daniel; Lobastov, Vladimir; Tkaczyk, J Eric

    2011-07-01

    Energy discriminating photon counting x-ray detectors can be subject to a wide range of flux rates if applied in clinical settings. Even when the incident rate is a small fraction of the detector's maximum periodic rate No, pulse pileup leads to count rate losses and spectral distortion. Although the deterministic effects can be corrected, the detrimental effect of pileup on image noise is not well understood and may limit the performance of photon counting systems. Therefore, the authors devise a method to determine the detector count statistics and imaging performance. The detector count statistics are derived analytically for an idealized pileup model with delta pulses of a nonparalyzable detector. These statistics are then used to compute the performance (e.g., contrast-to-noise ratio) for both single material and material decomposition contrast detection tasks via the Cramdr-Rao lower bound (CRLB) as a function of the detector input count rate. With more realistic unipolar and bipolar pulse pileup models of a nonparalyzable detector, the imaging task performance is determined by Monte Carlo simulations and also approximated by a multinomial method based solely on the mean detected output spectrum. Photon counting performance at different count rates is compared with ideal energy integration, which is unaffected by count rate. The authors found that an ideal photon counting detector with perfect energy resolution outperforms energy integration for our contrast detection tasks, but when the input count rate exceeds 20% N0, many of these benefits disappear. The benefit with iodine contrast falls rapidly with increased count rate while water contrast is not as sensitive to count rates. The performance with a delta pulse model is overoptimistic when compared to the more realistic bipolar pulse model. The multinomial approximation predicts imaging performance very close to the prediction from Monte Carlo simulations. The monoenergetic image with maximum contrast

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

    SciTech Connect

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

    2012-07-13

    Inspired by approach of Bignan and Martin-Didier (ESARDA 1991) we introduce novel (instrument independent) approach based on multiplication and passive neutron. Based on simulations of SFL-1 the accuracy of determination of {sup tot}Pu content with new approach is {approx}1.3-1.5%. Method applicable for DDA instrument, since it can measure both multiplication and passive neutron count rate. Comparison of pro's & con's of measuring/determining of {sup 239}Pu{sub eff} and {sup tot}Pu suggests a potential for enhanced diversion detection sensitivity.

  12. 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.

  13. Effects of dietary inclusion of silymarin on performance, intestinal morphology and ileal bacterial count in aflatoxin-challenged broiler chicks.

    PubMed

    Jahanian, E; Mahdavi, A H; Asgary, S; Jahanian, R

    2017-01-04

    This study was conducted to investigate the effect of dietary supplementation of silymarin on performance, jejunal morphology and ileal bacterial population in broiler chicks intoxicated with a mix of aflatoxins. A total of three hundred thirty six 7-day-old Ross broiler chicks were randomly distributed between seven experimental groups with four replicates of 12 birds each. Experimental treatments consisted of a control group (unchallenged), and a 2 × 3 factorial arrangement, including two aflatoxin levels (0.5 and 2 ppm) and three levels of silymarin (0, 500 and 1000 ppm). Birds were challenged with a mix of aflatoxins from 7 to 28 days of age. Results showed that increasing aflatoxin level resulted in decreased average daily feed intake (ADFI) and weight gain (ADWG), consequently impaired feed conversion ratio (FCR) throughout the trial period. Dietary supplementation of silymarin resulted in the marked increases in ADFI and ADWG, and improved FCR values in aflatoxin-challenged chicks. Ileal bacterial populations at days 28 and 42 of age were increased by incremental levels of aflatoxins. On the other hand, dietary silymarin supplementation suppressed ileal populations of Escherichia coli, Salmonella, Klebsiella and total negative bacteria in aflatoxicated birds. Increase in dietary aflatoxin level resulted in the decreased villi height, villi height-to-crypt depth ratio (VH:CD), villi surface area and apparent villi absorptive area, while it increased crypt depth, goblet cell count and lymphoid follicular diameter. Feeding silymarin at the level of 1000 ppm increased villi height and VH:CD in aflatoxicated birds. Present results indicate that dietary inclusion of silymarin could improve performance by suppressing ileal bacteria and enhancing absorptive surface area in aflatoxin-challenged broiler chicks.

  14. 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.

  15. Reticulocyte count

    MedlinePlus

    Anemia - reticulocyte ... A higher than normal reticulocytes count may indicate: Anemia due to red blood cells being destroyed earlier than normal ( hemolytic anemia ) Bleeding Blood disorder in a fetus or newborn ( ...

  16. How do I analyze thee? Let me count the ways: considering empathy in couple relationships using self and partner ratings.

    PubMed

    Busby, Dean M; Gardner, Brandt C

    2008-06-01

    In this article we describe some of the benefits and challenges of using self ratings and ratings of the partner to measure empathy and similar terms in couple research. If both members of the dyad are assessed, there will be four measures of the same variable. How to use these 4 measures in research and clinical work is a central question in this paper. We demonstrate 3 different latent models that can be used to analyze these ratings based on different theoretical premises. Using empathy as the independent variable with a longitudinal sample of 275 couples, structural equation models are used to evaluate the strength of these models in predicting relationship satisfaction. The findings indicate that the model that is consistent with the social constructionist perspective that focuses on the perceptions within the same person is a good fit to the data. Other models that compare ratings between members of the dyad do not fit the data well. The results demonstrate that perceptions of empathy do have a significant influence on relationship satisfaction across time, especially for females. However, it is largely males' perceptions of empathy of the self and the partner that influence relationship satisfaction for females.

  17. Performance and qualification of a multi-rate DPSK modem

    NASA Astrophysics Data System (ADS)

    Wang, Jade P.; Browne, C. A.; Burton, C. D.; Caplan, D. O.; Carney, J. J.; Chavez, M. L.; Fitzgerald, J. J.; Gaschits, I.; Geisler, D. J.; Hamilton, S. A.; Henion, S. R.; Lund, G.; Magliocco, R. J.; Mikulina, O. V.; Murphy, R. J.; Rao, H. G.; Seaver, M. M.; Spellmeyer, N. W.

    2014-03-01

    Recently, we demonstrated a multi-rate DPSK modem with high-sensitivity over a wide dynamic range, which can significantly benefit performance and cost of NASA's Laser Communication Relay Demonstration. This increased flexibility, combined with the need to verify robust operation under challenging free-space environmental conditions, results in a large number of operational states which must be accurately and thoroughly tested. To support this, we developed test and diagnostic capabilities that can be easily reconfigured to assess modem performance across a wide range of data rates and operational modes. These capabilities include internal self-test modes in which test waveforms can be directed from the transmitter into the receiver to determine modem communications performance. We used these self-test capabilities to demonstrate robust performance in realistic environments during thermal-vacuum, shock/vibration, and EMI/EMC testing.

  18. Communication satellite ground station receiver performance at low data rates

    NASA Astrophysics Data System (ADS)

    Riddle, L. P.

    Performance of satellite ground station receivers at low data rates is analyzed for power-limited satellites, when various amounts of frequency dynamics are present. Specifically, the lowest data rates for which the receiver can successfully demodulate suppressed-carrier BPSK data under a wide variety of conditions are determined. Minimum data rates on the order of 100 to 1400 bits per second are achievable with a bit error probability less than 0.00001 and with a mean time to cycle slip on the order of 1/2 hour or more, when Costas loops are employed for carrier extraction.

  19. Communication satellite ground station receiver performance at low data rates

    NASA Technical Reports Server (NTRS)

    Riddle, L. P.

    1982-01-01

    Performance of satellite ground station receivers at low data rates is analyzed for power-limited satellites, when various amounts of frequency dynamics are present. Specifically, the lowest data rates for which the receiver can successfully demodulate suppressed-carrier BPSK data under a wide variety of conditions are determined. Minimum data rates on the order of 100 to 1400 bits per second are achievable with a bit error probability less than 0.00001 and with a mean time to cycle slip on the order of 1/2 hour or more, when Costas loops are employed for carrier extraction.

  20. Mars sedimentary rock erosion rates constrained using crater counts, with applications to organic-matter preservation and to the global dust cycle

    NASA Astrophysics Data System (ADS)

    Kite, Edwin S.; Mayer, David P.

    2017-04-01

    Small-crater counts on Mars light-toned sedimentary rock are often inconsistent with any isochron; these data are usually plotted then ignored. We show (using an 18-HiRISE-image, > 104-crater dataset) that these non-isochron crater counts are often well-fit by a model where crater production is balanced by crater obliteration via steady exhumation. For these regions, we fit erosion rates. We infer that Mars light-toned sedimentary rocks typically erode at ∼102 nm/yr, when averaged over 10 km2 scales and 107-108 yr timescales. Crater-based erosion-rate determination is consistent with independent techniques, but can be applied to nearly all light-toned sedimentary rocks on Mars. Erosion is swift enough that radiolysis cannot destroy complex organic matter at some locations (e.g. paleolake deposits at SW Melas), but radiolysis is a severe problem at other locations (e.g. Oxia Planum). The data suggest that the relief of the Valles Marineris mounds is currently being reduced by wind erosion, and that dust production on Mars < 3 Gya greatly exceeds the modern reservoir of mobile dust.

  1. Performance and design of InGaAs /InP photodiodes for single-photon counting at 1.55 microm.

    PubMed

    Hiskett, P A; Buller, G S; Loudon, A Y; Smith, J M; Gontijo, I; Walker, A C; Townsend, P D; Robertson, M J

    2000-12-20

    The performance of selected, commercially available InGaAs/InP avalanche photodiodes operating in a photon-counting mode at an incident wavelength of 1.55 microm is described. A discussion on the optimum operating conditions and their relationship to the electric field distribution within the device is presented.

  2. Performance of absolute CD4+ count in predicting co-infection with human T-lymphotropic virus type 1 in antiretroviral-naive HIV-infected patients.

    PubMed

    Gudo, E S; Bhatt, N B; Augusto, O; Semá, C; Savino, W; Ferreira, O C; Jani, I V

    2012-10-01

    Early identification of patients co-infected with HIV and human T-lymphotropic virus type 1 (HTLV-1) is essential to improve care, as CD4+ T-cell counts have been revealed to be an unreliable laboratory parameter to monitor HIV infection in co-infection. Unfortunately, HTLV-1 testing is not currently available in sub-Saharan Africa. We conducted this study to determine the performance of absolute CD4+ T-cell count estimation in guiding the clinical suspicion of co-infection. A cross-sectional survey was conducted in antiretroviral-naïve HIV (AN-HIV) patients attending an HIV outpatient clinic in Maputo city, Mozambique. Seven hundred and one AN-HIV patients were enrolled in the study. The prevalence of HTLV-1 co-infection was 4.5% (95% confidence interval [CI] 3.0-6.0%). Logistic regression analysis showed that CD4+ T-cell count was an independent predictor of co-infection (P value: 0.000). The performance of absolute CD4+ T-cell counts in predicting co-infection was higher in symptomatic HIV patients when compared with asymptomatic HIV patients. The best performance was achieved with the cut-off of CD4+ count of 500 cells/mm(3), which gave sensitivity, specificity, positive and negative predictive values of 54.2%, 87.2%, 24.0% and 96.2%, respectively. In conclusion, our data provide evidence that the absolute CD4+ T-cell count is of moderate accuracy in guiding the clinical suspicion of co-infection in AN-HIV and its implementation could improve the care provided to a significant number of HIV patients in Mozambique.

  3. Performance of a space-based wavelet compressor for plasma count data on the MMS Fast Plasma Investigation

    NASA Astrophysics Data System (ADS)

    Barrie, A. C.; Smith, S. E.; Dorelli, J. C.; Gershman, D. J.; Yeh, P.; Schiff, C.; Avanov, L. A.

    2017-01-01

    Data compression has been a staple of imaging instruments for years. Recently, plasma measurements have utilized compression with relatively low compression ratios. The Fast Plasma Investigation (FPI) on board the Magnetospheric Multiscale (MMS) mission generates data roughly 100 times faster than previous plasma instruments, requiring a higher compression ratio to fit within the telemetry allocation. This study investigates the performance of a space-based compression standard employing a Discrete Wavelet Transform and a Bit Plane Encoder (DWT/BPE) in compressing FPI plasma count data. Data from the first 6 months of FPI operation are analyzed to explore the error modes evident in the data and how to adapt to them. While approximately half of the Dual Electron Spectrometer (DES) maps had some level of loss, it was found that there is little effect on the plasma moments and that errors present in individual sky maps are typically minor. The majority of Dual Ion Spectrometer burst sky maps compressed in a lossless fashion, with no error introduced during compression. Because of induced compression error, the size limit for DES burst images has been increased for Phase 1B. Additionally, it was found that the floating point compression mode yielded better results when images have significant compression error, leading to floating point mode being used for the fast survey mode of operation for Phase 1B. Despite the suggested tweaks, it was found that wavelet-based compression, and a DWT/BPE algorithm in particular, is highly suitable to data compression for plasma measurement instruments and can be recommended for future missions.

  4. Social motivation in prospective memory: higher importance ratings and reported performance rates for social tasks.

    PubMed

    Penningroth, Suzanna L; Scott, Walter D; Freuen, Margaret

    2011-03-01

    Few studies have addressed social motivation in prospective memory (PM). In a pilot study and two main studies, we examined whether social PM tasks possess a motivational advantage over nonsocial PM tasks. In the pilot study and Study 1, participants listed their real-life important and less important PM tasks. Independent raters categorized the PM tasks as social or nonsocial. Results from both studies showed a higher proportion of tasks rated as social when important tasks were requested than when less important tasks were requested. In Study 1, participants also reported whether they had remembered to perform each PM task. Reported performance rates were higher for tasks rated as social than for those rated as nonsocial. Finally, in Study 2, participants rated the importance of two hypothetical PM tasks, one social and one nonsocial. The social PM task was rated higher in importance. Overall, these findings suggest that social PM tasks are viewed as more important than nonsocial PM tasks and they are more likely to be performed. We propose that consideration of the social relevance of PM will lead to a more complete and ecologically valid theoretical description of PM performance. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

  5. 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…

  6. 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…

  7. 5 CFR 9701.409 - Rating and rewarding performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....409 Section 9701.409 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Performance Management § 9701.409 Rating and rewarding...

  8. Using the unmatched count technique to improve base rate estimates of risky driving behaviours among veterans of the wars in Iraq and Afghanistan.

    PubMed

    Sheppard, Sean C; Earleywine, Mitch

    2013-12-01

    Few studies have investigated base rate estimates of risky driving behaviours among veterans of the wars in Afghanistan and Iraq despite evidence suggesting such behaviours result in increased death rates. In addition, published estimates of driving behaviours may be subject to a significant response bias via the impact of perceived mental health stigma on honest self-reporting. The present study compared the unmatched count technique, a form of randomised response technique used to mitigate biased responding, with traditional anonymous self-report to gain information about base rates of risky driving behaviours among combat veterans. Cross-sectional data gathered as part of a study of attitudes and behaviours related to military service provided estimates of target activities. Six facets of risky driving (horn honking, carrying firearms in the vehicle, drinking and driving, screaming at other drivers, following other drivers to complain, and tailgating) were assessed. In our sample of 1351 combat veterans, the unmatched count technique revealed significantly higher rates relative to traditional anonymous assessment specifically for horn honking in anger (22.1% vs 13.6%), carrying firearms (51.1% vs 32.2%), and drinking and driving (77.8% vs 54.0%). There were no significant differences for the remaining three items. The high level of morbidity associated with risky driving and motor vehicle crashes is a significant concern in the combat veteran population. These data suggest the presence of a strong response bias associated with endorsing certain risky driving behaviours, potentially leading to serious underestimation of these problem behaviours in standard anonymous questionnaires.

  9. Base rates, multiple indicators, and comprehensive forensic evaluations: why sexualized behavior still counts in assessments of child sexual abuse allegations.

    PubMed

    Everson, Mark D; Faller, Kathleen Coulborn

    2012-01-01

    Developmentally inappropriate sexual behavior has long been viewed as a possible indicator of child sexual abuse. In recent years, however, the utility of sexualized behavior in forensic assessments of alleged child sexual abuse has been seriously challenged. This article addresses a number of the concerns that have been raised about the diagnostic value of sexualized behavior, including the claim that when population base rates for abuse are properly taken into account, the diagnostic value of sexualized behavior is insignificant. This article also identifies a best practice comprehensive evaluation model with a methodology that is effective in mitigating such concerns.

  10. 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

  11. 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

  12. AUTOMATIC COUNTING APPARATUS

    DOEpatents

    Howell, W.D.

    1957-08-20

    An apparatus for automatically recording the results of counting operations on trains of electrical pulses is described. The disadvantages of prior devices utilizing the two common methods of obtaining the count rate are overcome by this apparatus; in the case of time controlled operation, the disclosed system automatically records amy information stored by the scaler but not transferred to the printer at the end of the predetermined time controlled operations and, in the case of count controlled operation, provision is made to prevent a weak sample from occupying the apparatus for an excessively long period of time.

  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.

  14. Method for Performing Aerobic Plate Counts of Anhydrous Cosmetics Utilizing Tween 60 and Arlacel 80 as Dispersing Agents

    PubMed Central

    McConville, John F.; Anger, Claude B.; Anderson, David W.

    1974-01-01

    An aqueous diluent containing Tween 60 and Arlacel 80 gave greater recovery of microorganisms when compared with two common diluents as determined by aerobic plate count of inoculated anhydrous cosmetics. The greater recovery was caused by better dispersion of the anhydrous cosmetics in the diluents. Images PMID:4203790

  15. Neutron counting with cameras

    SciTech Connect

    Van Esch, Patrick; Crisanti, Marta; Mutti, Paolo

    2015-07-01

    A research project is presented in which we aim at counting individual neutrons with CCD-like cameras. We explore theoretically a technique that allows us to use imaging detectors as counting detectors at lower counting rates, and transits smoothly to continuous imaging at higher counting rates. As such, the hope is to combine the good background rejection properties of standard neutron counting detectors with the absence of dead time of integrating neutron imaging cameras as well as their very good spatial resolution. Compared to Xray detection, the essence of thermal neutron detection is the nuclear conversion reaction. The released energies involved are of the order of a few MeV, while X-ray detection releases energies of the order of the photon energy, which is in the 10 KeV range. Thanks to advances in camera technology which have resulted in increased quantum efficiency, lower noise, as well as increased frame rate up to 100 fps for CMOS-type cameras, this more than 100-fold higher available detection energy implies that the individual neutron detection light signal can be significantly above the noise level, as such allowing for discrimination and individual counting, which is hard to achieve with X-rays. The time scale of CMOS-type cameras doesn't allow one to consider time-of-flight measurements, but kinetic experiments in the 10 ms range are possible. The theory is next confronted to the first experimental results. (authors)

  16. White Blood Cell Count

    MedlinePlus

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

  17. Measuring target detection performance in paradigms with high event rates.

    PubMed

    Bendixen, Alexandra; Andersen, Søren K

    2013-05-01

    Combining behavioral and neurophysiological measurements inevitably implies mutual constraints, such as when the neurophysiological measurement requires fast-paced stimulus presentation and hence the attribution of a behavioral response to a particular preceding stimulus becomes ambiguous. We develop and test a method for validly assessing behavioral detection performance in spite of this ambiguity. We examine four approaches taken in the literature to treat such situations. We analytically derive a new variant of computing the classical parameters of signal detection theory, hit and false alarm rates, adapted to fast-paced paradigms. Each of the previous approaches shows specific shortcomings (susceptibility towards response window choice, biased estimates of behavioral detection performance). Superior performance of our new approach is demonstrated for both simulated and empirical behavioral data. Further evidence is provided by reliable correspondence between behavioral performance and the N2b component as an electrophysiological indicator of target detection. The appropriateness of our approach is substantiated by both theoretical and empirical arguments. We demonstrate an easy-to-implement solution for measuring target detection performance independent of the rate of event presentation. Thus overcoming the measurement bias of previous approaches, our method will help to clarify the behavioral relevance of different measures of cortical activation. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  18. 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

  19. Low-Cost Disposable Cartridge for Performing a White Blood Cell Count and Partial Differential at the Point-of-Care*

    PubMed Central

    Majors, Catherine E.; Pawlowski, Michal E.; Tkaczyk, Tomasz; Richards-Kortum, Rebecca R.

    2015-01-01

    Being able to perform a white blood cell (WBC) count and differential is a crucial laboratory test for basic diagnostic practices. In this paper, we demonstrate proof of concept results for a disposable cartridge that could be used to perform a WBC count and 3-part differential at the point-of-care. The cartridge is composed of a glass slide, a layer of transfer tape, and a glass cover slip and incorporates acridine orange for cell staining and sub-type differentiation; the stained blood is then imaged, and image analysis techniques return a WBC count and 3-part differential. The cartridge was tested on a laboratory microscope with 3 normal samples, and had promising results with 85.7% of images resulting in a WBC count with ±15% of the true value. Further, the 3-part differential concentrations determined using the disposable cartridge had strong correlations with the true concentrations (R2 values of 0.9986, 0.9421, and 0.6942 for granulocytes, lymphocytes, and monocytes, respectively). Preliminary designs for a low-cost, portable microscope have been created and are currently being prototyped. PMID:25918749

  20. Performance evaluation of the Sysmex XN-1000 hematology analyzer in assessment of the white blood cell count differential in pediatric specimens.

    PubMed

    Becker, P-H; Fenneteau, O; Da Costa, L

    2016-02-01

    The automated XN-1000 hematology analyzer enables to perform a blood cell count and a leukocyte differential. When abnormal cells were detected, a flag was generated by the analyzer and a manual microscopic examination of the corresponding blood film was performed. We compared the white blood cell differentials provided by the automated hematology analyzer XN-1000 in a pediatric population (n = 765) with those obtained through microscopic examination by cytologists and those obtained using a previous version of this analyzer, the XE-2100. Leukocytes count as well as flags sensitivity and specificity was analyzed. The leukocytes count provided by the analyzer is in good accordance with the differential obtained by manual count in children older than 3 months. The sensitivity for blast detection is 99% and the detection of reactive cells is 63%. The flag specificity remains low (<35%) for blood samples collected from infants between 8 days and 2 years of age, but increases up to 67% thereafter. The results obtained with the XN-1000 analyzer show an improvement in comparison with those obtained with the XE-2100 analyzer. The automated WBC differential provided by the XN-1000 analyzer in the pediatric setting is accurate, but a meticulous microscopic examination of blood smears remains necessary for infants up to 3 months of age to validate the analyzer flags. © 2015 John Wiley & Sons Ltd.

  1. Low-Cost Disposable Cartridge for Performing a White Blood Cell Count and Partial Differential at the Point-of-Care.

    PubMed

    Majors, Catherine E; Pawlowski, Michal E; Tkaczyk, Tomasz; Richards-Kortum, Rebecca R

    2014-10-01

    Being able to perform a white blood cell (WBC) count and differential is a crucial laboratory test for basic diagnostic practices. In this paper, we demonstrate proof of concept results for a disposable cartridge that could be used to perform a WBC count and 3-part differential at the point-of-care. The cartridge is composed of a glass slide, a layer of transfer tape, and a glass cover slip and incorporates acridine orange for cell staining and sub-type differentiation; the stained blood is then imaged, and image analysis techniques return a WBC count and 3-part differential. The cartridge was tested on a laboratory microscope with 3 normal samples, and had promising results with 85.7% of images resulting in a WBC count with ±15% of the true value. Further, the 3-part differential concentrations determined using the disposable cartridge had strong correlations with the true concentrations (R(2) values of 0.9986, 0.9421, and 0.6942 for granulocytes, lymphocytes, and monocytes, respectively). Preliminary designs for a low-cost, portable microscope have been created and are currently being prototyped.

  2. [Performance based regulation: a strategy to increase breastfeeding rates].

    PubMed

    Cobo-Armijo, Fernanda; Charvel, Sofía; Hernández-Ávila, Mauricio

    2017-01-01

    The decreasing breastfeeding rate in México is of public health concern. In this paper we discus an innovative regulatory approach -Performance Based Regulation- and its application to improve breastfeeding rates. This approach, forces industry to take responsibility for the lack of breastfeeding and its consequences. Failure to comply with this targets results in financial penalties. Applying performance based regulation as a strategy to improve breastfeeding is feasible because: the breastmilk substitutes market is an oligopoly, hence it is easy to identify the contribution of each market participant; the regulation's target population is clearly defined; it has a clear regulatory standard which can be easily evaluated, and sanctions to infringement can be defined under objective parameters. modify public policy, celebrate concertation agreements with the industry, create persuasive sanctions, strengthen enforcement activities and coordinate every action with the International Code of Marketing of Breast-milk Substitutes.

  3. 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)

  4. 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…

  5. 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)

  6. 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…

  7. The Effects of Ratee Characteristics on Rater Performance Appraisal Behavior.

    DTIC Science & Technology

    1983-11-01

    should spend more time observing Kate and less time working on the 9.,e , e{e,,,,. ; c e’. ’,..... : ;..: ..-.- . . . . . . ... % Page-17 Favero & Ilg...observing, the more accurate were the performance ratings. Page-23 Favero & Ilgen Henneman & Wexley (in press) found a similar relationship between...Page-27 Favero & Ilgen Footnotes 1. We wish to thank Patricia C . Smith for providing us with this scale. 2. Other manipulations and measures included

  8. Determinants of Performance Rating Accuracy: A Field Study

    DTIC Science & Technology

    1993-04-01

    observe relevant job behaviors and make more accurate ratings. Although some studies have found no relationship (Klores, 1966; Schwab & Heneman , 1978) or...Schwab, D. P., & Heneman , H. G. (1978). Age stereotyping in performance appraisal. Journal of Psvcholoav, §1, 573-578. 59 Smithers, J. W., & Reilly, R. R...Equipment: T.O. l-iA-14; RG 58 RF Cable, Connector (crimp type) Solder, Flux, Soldering Iron, Knife, Scissors, Cable Cutter, Eye Protection, Scribe

  9. 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 %.

  10. Gamma-ray spectroscopy at MHz counting rates with a compact LaBr3 detector and silicon photomultipliers for fusion plasma applications.

    PubMed

    Nocente, M; Rigamonti, D; Perseo, V; Tardocchi, M; Boltruczyk, G; Broslawski, A; Cremona, A; Croci, G; Gosk, M; Kiptily, V; Korolczuk, S; Mazzocco, M; Muraro, A; Strano, E; Zychor, I; Gorini, G

    2016-11-01

    Gamma-ray spectroscopy measurements at MHz counting rates have been carried out, for the first time, with a compact spectrometer based on a LaBr3 scintillator and silicon photomultipliers. The instrument, which is also insensitive to magnetic fields, has been developed in view of the upgrade of the gamma-ray camera diagnostic for α particle measurements in deuterium-tritium plasmas of the Joint European Torus. Spectra were measured up to 2.9 MHz with a projected energy resolution of 3%-4% in the 3-5 MeV range, of interest for fast ion physics studies in fusion plasmas. The results reported here pave the way to first time measurements of the confined α particle profile in high power plasmas of the next deuterium-tritium campaign at the Joint European Torus.

  11. Gamma-ray spectroscopy at MHz counting rates with a compact LaBr{sub 3} detector and silicon photomultipliers for fusion plasma applications

    SciTech Connect

    Nocente, M.; Rigamonti, D.; Croci, G.; Gorini, G.; Perseo, V.; Tardocchi, M.; Cremona, A.; Muraro, A.; Boltruczyk, G.; Broslawski, A.; Gosk, M.; Korolczuk, S.; Zychor, I.; Kiptily, V.; Mazzocco, M.; Strano, E.; Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon

    2016-11-15

    Gamma-ray spectroscopy measurements at MHz counting rates have been carried out, for the first time, with a compact spectrometer based on a LaBr{sub 3} scintillator and silicon photomultipliers. The instrument, which is also insensitive to magnetic fields, has been developed in view of the upgrade of the gamma-ray camera diagnostic for α particle measurements in deuterium-tritium plasmas of the Joint European Torus. Spectra were measured up to 2.9 MHz with a projected energy resolution of 3%-4% in the 3-5 MeV range, of interest for fast ion physics studies in fusion plasmas. The results reported here pave the way to first time measurements of the confined α particle profile in high power plasmas of the next deuterium-tritium campaign at the Joint European Torus.

  12. Gamma-ray spectroscopy at MHz counting rates with a compact LaBr3 detector and silicon photomultipliers for fusion plasma applications

    NASA Astrophysics Data System (ADS)

    Nocente, M.; Rigamonti, D.; Perseo, V.; Tardocchi, M.; Boltruczyk, G.; Broslawski, A.; Cremona, A.; Croci, G.; Gosk, M.; Kiptily, V.; Korolczuk, S.; Mazzocco, M.; Muraro, A.; Strano, E.; Zychor, I.; Gorini, G.

    2016-11-01

    Gamma-ray spectroscopy measurements at MHz counting rates have been carried out, for the first time, with a compact spectrometer based on a LaBr3 scintillator and silicon photomultipliers. The instrument, which is also insensitive to magnetic fields, has been developed in view of the upgrade of the gamma-ray camera diagnostic for α particle measurements in deuterium-tritium plasmas of the Joint European Torus. Spectra were measured up to 2.9 MHz with a projected energy resolution of 3%-4% in the 3-5 MeV range, of interest for fast ion physics studies in fusion plasmas. The results reported here pave the way to first time measurements of the confined α particle profile in high power plasmas of the next deuterium-tritium campaign at the Joint European Torus.

  13. Asian-American Patient Ratings of Physician Primary Care Performance

    PubMed Central

    Taira, Deborah A; Safran, Dana Gelb; Seto, Todd B; Rogers, William H; Kosinski, Mark; Ware, John E; Lieberman, Naomi; Tarlov, Alvin R

    1997-01-01

    OBJECTIVE To examine how Asian-American patients’ ratings of primary care performance differ from those of whites, Latinos, and African-Americans. DESIGN Retrospective analyses of data collected in a cross-sectional study using patient questionnaires. SETTING University hospital primary care group practice. PARTICIPANTS In phase 1, successive patients who visited the study site for appointments were asked to complete the survey. In phase 2, successive patients were selected who had most recently visited each physician, going back as far as necessary to obtain 20 patients for each physician. In total, 502 patients were surveyed, 5% of whom were Asian-American. MAIN RESULTS After adjusting for potential confounders, Asian-Americans rated overall satisfaction and 10 of 11 scales assessing primary care significantly lower than whites did. Dimensions of primary care that were assessed include access, comprehensiveness of care, integration, continuity, clinical quality, interpersonal treatment, and trust. There were no differences for the scale of longitudinal continuity. On average, the rating scale scores of Asian-Americans were 12 points lower than those of whites (on 100-point scales). CONCLUSIONS We conclude that Asian-American patients rate physician primary care performance lower than do whites, African-Americans, and Latinos. Future research needs to focus on Asian-Americans to determine the generalizability of these findings and the extent to which they reflect differences in survey response tendencies or actual quality differences. PMID:9127228

  14. 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.

  15. Pasture forages, supplementation rate, and stocking rate effects on dairy cow performance.

    PubMed

    Fike, J H; Staples, C R; Sollenberger, L E; Macoon, B; Moore, J E

    2003-04-01

    Objectives were to evaluate effects of forage species, stocking rate, and supplementation rate on performance and physiology of grazing lactating Holstein cows under intensive rotational stocking management during summer. Eight treatments were arranged in a 2 x 2 x 2 factorial design. Animals (n = 62) grazed pastures of Tifton 85 bermudagrass or Florigraze rhizoma peanut, a tropical legume. Low and high stocking rates were 7.5 and 10.0 cows/ha for bermudagrass and 5.0 and 7.5 cows/ha for rhizoma peanut. Within each forage-stocking rate combination, cows were fed supplement at 0.33 or 0.5 kg of supplement (as-fed basis)/kg daily milk production. Cows grazing rhizoma peanut pastures produced more milk (16.9 vs. 15.4 kg/d) but had higher rectal temperatures (39.4 vs. 39.1 degrees C). Milk production per cow was improved at the higher stocking rate for bermudagrass but was reduced at the higher stocking rate for peanuts. Increasing supplementation rate boosted plasma glucose, milk production, and milk protein percent. Increased supplementation rate had a greater positive impact on milk production of cows grazing bermudagrass compared to rhizoma peanut (21.9 vs. 10.6% increase) due to a lower substitution of grain for forage intake. Organic matter intakes of forage, supplement, and total diet were greatest by cows grazing rhizoma peanut pastures and averaged 12.4, 6.1, and 18.5 kg/d compared to 9.2, 5.4, and 14.6 kg/d for cows grazing bermudagrass. Despite lower individual feed intake and performance, production per unit land area was 29% greater (112 vs. 90 kg of milk/ha per d) for cows grazing bermudagrass due to the greater stocking rate possible with that forage. Only cows supplemented at the high rate and kept at the high stocking rate on bermudagrass maintained body weight. Cows on other treatments lost body weight. Tifton 85 bermudagrass appears to be an excellent summer forage for dairy cows grazing in the southeastern U.S. given its nutritive value

  16. Evaluating the performance of equations for estimating glomerular filtration rate.

    PubMed

    Stevens, Lesley A; Zhang, Yaping; Schmid, Christopher H

    2008-01-01

    Glomerular filtration rate (GFR) is an important indicator of kidney function, critical for detection, evaluation and management of chronic kidney disease (CKD). GFR cannot be practically measured in most clinical or research settings; therefore, estimating equations are used as a primary measure of kidney function. A considerable body of literature now evaluates the performance of GFR estimating equations. The results of these studies are often not comparable, because of variation in GFR measurement methods, endogenous filtration marker assays and tools by which the equations were evaluated. In this article, methods for the evaluation of GFR estimating equations are discussed. Topics addressed include statistical methods used in development and validation of equations; explanation of measures of performance used for evaluation, with focus on distinction between bias, precision and accuracy, and with reference to examples of published evaluations of creatinine- and cystatin C-based equations; explanation of errors in GFR estimates; and challenges and questions in reporting performance of GFR estimating equations.

  17. Suppression of emission rates improves sonar performance by flying bats.

    PubMed

    Adams, Amanda M; Davis, Kaylee; Smotherman, Michael

    2017-01-31

    Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat's calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference.

  18. Suppression of emission rates improves sonar performance by flying bats

    PubMed Central

    Adams, Amanda M.; Davis, Kaylee; Smotherman, Michael

    2017-01-01

    Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat’s calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference. PMID:28139707

  19. Fighter pilots' heart rate, heart rate variation and performance during instrument approaches.

    PubMed

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

    2016-10-01

    Fighter pilots' heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV's ability to differentiate the sub-standard performance approaches from the high-performance approaches. Practitioner Summary: This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot's performance.

  20. Field performance of a low-cost and fully-automated blood counting system operated by trained and untrained users (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Xie, Dengling; Xie, Yanjun; Liu, Peng; Tong, Lieshu; Chu, Kaiqin; Smith, Zachary J.

    2017-02-01

    Current flow-based blood counting devices require expensive and centralized medical infrastructure and are not appropriate for field use. In this paper we report a method to count red blood cells, white blood cells as well as platelets through a low-cost and fully-automated blood counting system. The approach consists of using a compact, custom-built microscope with large field-of-view to record bright-field and fluorescence images of samples that are diluted with a single, stable reagent mixture and counted using automatic algorithms. Sample collection is performed manually using a spring loaded lancet, and volume-metering capillary tubes. The capillaries are then dropped into a tube of pre-measured reagents and gently shaken for 10-30 seconds. The sample is loaded into a measurement chamber and placed on a custom 3D printed platform. Sample translation and focusing is fully automated, and a user has only to press a button for the measurement and analysis to commence. Cost of the system is minimized through the use of custom-designed motorized components. We performed a series of comparative experiments by trained and untrained users on blood from adults and children. We compare the performance of our system, as operated by trained and untrained users, to the clinical gold standard using a Bland-Altman analysis, demonstrating good agreement of our system to the clinical standard. The system's low cost, complete automation, and good field performance indicate that it can be successfully translated for use in low-resource settings where central hematology laboratories are not accessible.

  1. 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…

  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. Environmental performance rating and disclosure: China's Green Watch program.

    PubMed

    Wang, Hua; Bi, Jun; Wheeler, David; Wang, Jinnan; Cao, Dong; Lu, Genfa; Wang, Yuan

    2004-06-01

    In this paper we describe a new incentive-based pollution control program in China, in which the environmental performance of firms is rated from best to worst using five colors--green, blue, yellow, red and black--and the ratings are disseminated to the public through the media. We focus on the first two municipal disclosure programs, which have been implemented at very different levels of economic and institutional development. In both cases, the increases in compliance with pollution regulations have been similar to increases produced by public disclosure programs in Indonesia, the Philippines, and Vietnam. The results suggest that incentives created by public disclosure may significantly reduce pollution in China, even though environmental NGO's play little role and there is no formal channel for public participation in environmental regulation.

  4. [Platelet count in the cat].

    PubMed

    Moritz, A; Hoffmann, C

    1997-11-01

    The technique of collecting blood samples is primarily responsible for the appearance of platelet-agglomeration in cats. Blood obtained by the conventional way ("one syringe technology", drips of blood) caused in 52% of the cases an activation of the large and therefore active thrombocytes however. Rejection of the first 2-5 ml blood for the platelet count ("two syringe technology") reduced the rate of platelet-agglomeration significantly. No big differences in platelet-agglomeration were found with regard to the place used for collecting blood (V. cephalica antebrachii/V. jugularis). Platelet-agglutination was observed with Li-Heparin, K-EDTA, Na-Citrat or ACD anticoagulated blood samples. Citrat (Na-Citrat, ACD) seemed to have a stabilizing effect on feline thrombocytes as has been described for human thrombocytes. The platelet count in cats should be performed within 30 minutes.

  5. 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

  6. The Impact of HIV Infection and CD4 Cell Count on the Performance of an Interferon Gamma Release Assay in Patients with Pulmonary Tuberculosis

    PubMed Central

    Aabye, Martine G.; Ravn, Pernille; PrayGod, George; Jeremiah, Kidola; Mugomela, Apolinary; Jepsen, Maria; Faurholt, Daniel; Range, Nyagosya; Friis, Henrik; Changalucha, John; Andersen, Aase B.

    2009-01-01

    Background The performance of the tuberculosis specific Interferon Gamma Release Assays (IGRAs) has not been sufficiently documented in tuberculosis- and HIV-endemic settings. This study evaluated the sensitivity of the QuantiFERON TB-Gold In-Tube (QFT-IT) in patients with culture confirmed pulmonary tuberculosis (PTB) in a TB- and HIV-endemic population and the effect of HIV-infection and CD4 cell count on test performance. Methodology/Principal Findings 161 patients with sputum culture confirmed PTB were subjected to HIV- and QFT-IT testing and measurement of CD4 cell count. The QFT-IT was positive in 74% (119/161; 95% CI: 67–81%). Sensitivity was higher in HIV-negative (75/93) than in HIV-positive (44/68) patients (81% vs. 65%, p = 0.02) and increased with CD4 cell count in HIV-positive patients (test for trend p = 0.03). 23 patients (14%) had an indeterminate result and this proportion decreased with increasing CD4 cell count in HIV-positive patients (test for trend p = 0.03). Low CD4 cell count (<300 cells/µl) did not account for all QFT-IT indeterminate nor all negative results. Sensitivity when excluding indeterminate results was 86% (95% CI: 81–92%) and did not differ between HIV-negative and HIV–positive patients (88 vs. 83%, p = 0.39). Conclusions/Significance Sensitivity of the QFT-IT for diagnosing active PTB infection was reasonable when excluding indeterminate results and in HIV-negative patients. However, since the test missed more than 10% of patients, its potential as a rule-out test for active TB disease is limited. Furthermore, test performance is impaired by low CD4 cell count in HIV-positive patients and possibly by other factors as well in both HIV-positive and HIV-negative patients. This might limit the potential of the test in populations where HIV-infection is prevalent. PMID:19156218

  7. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The performance of BD FACSPresto™ for CD4 T-cell count, CD4% and hemoglobin concentration test in Ethiopia.

    PubMed

    Gebremicael, Gebremedhin; Belay, Yohanes; Girma, Fitsum; Abreha, Yemane; Gebreegziabxier, Atsbeha; Tesfaye, Simret; Messele, Zelalem; Assefa, Yibeltal; Bellete, Bahrie; Kassa, Desta; Vojnov, Lara

    2017-01-01

    In Ethiopia, CD4+ T-cell counting is still required for all patients at baseline before antiretroviral therapy (ART) and to determine eligibility and follow-up of opportunistic infection prophylaxis. However, access to CD4+ T cell count in rural health facilities remains a major challenge in Ethiopia like other resource-limited settings. Both capillary and venous blood was drawn from each of 325 study participant recruited in Addis Ababa and surroundings. The CD4+ T-cell count, CD4%, and hemoglobin (Hgb) were tested at one of the four study health facilities using capillary blood and BD FACSPresto™ device. These tests were also done at the national HIV reference laboratory, using venous blood with BD FACSCalibur™, Sysmex XT-1800i™, and BD FACSPresto™. BD FACSPresto™ had an absolute mean bias of -13.3 cells/ul (-2.99%) and 28.3 cells/μl (6.4%) using venous and capillary blood, respectively, compared with BD FACSCalibur™. The absolute CD4 assay on the BD FACSPresto™ had a regression coefficient (R2) of 0.87 and 0.92 using capillary blood and venous blood samples, respectively, compared with BD FACSCalibur™. The percentage similarity of the BD FACSPresto™ using capillary and venous blood was 105.2% and 99.3%, respectively. The sensitivity of the FACSPresto™ using threshold of 500 cells/μl for ART eligibility using capillary and venous blood was 87.9 and 94.3%, while the specificity was 91.4 and 83.8%, respectively. Furthermore, the BD FACSPresto™ had an absolute mean bias of -0.2 dl/μl (0.0%) (95% LOA: -1.7, 1.3) and -0.59 dl/μl (0.1%) (95% LOA: -1.49, 0.31) for Hgb using capillary and venous blood compared with the Sysmex XT-1800i™, respectively. Our results showed acceptable agreement between the BD FACSPresto™ and BD FACSCalibur™ for CD4+ T-cell counting and CD4%; and between the BD FACSPresto™ and Sysmex XT-1800i™for measuring Hgb concentration.

  9. The MIC photon counting detector

    NASA Astrophysics Data System (ADS)

    Fordham, J. L. A.; Bone, D. A.; Oldfield, M. K.; Bellis, J. G.; Norton, T. J.

    1992-12-01

    The MIC (Microchannel plate Intensified CCD (Charge Coupled Device)) detector is an advanced performance Micro Channel Plate (MCP) intensified CCD photon counting detector developed for high resolution, high dynamic range, astronomical applications. The heart of the detector is an MCP intensifier developed specifically for photon counting applications. The maximum detector format is 3072 by 2304 pixels. The measured resolution of the detector system is 18 micrometers FWHM at 490 nm. The detector is linear to approximately 1,000,000 events/detector area/sec on a flat field and linear to count rates up to 200 events/object/s on star images. Two versions of the system have been developed. The first for ground based astronomical applications based around a 40 mm diameter intensifier, was proven in trials at a number of large optical telescopes. The second, specifically for the ESA X-Ray Multi Mirror Mission (XMM), where the MIC has been accepted as the blue detector for the incorporated Optical Monitor (OM). For the XMM-OM, the system is based around a 25 mm diameter intensifier. At present, under development, is a 75 mm diameter version of the detector which will have a maximum format of 6144 by 4608 pixels. Details of the MIC detector and its performance are presented.

  10. 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

  11. Reduction effect of bacterial counts by preoperative saline lavage of the stomach in performing laparoscopic and endoscopic cooperative surgery.

    PubMed

    Mori, Hirohito; Kobara, Hideki; Tsushimi, Takaaki; Fujihara, Shintaro; Nishiyama, Noriko; Matsunaga, Tae; Ayaki, Maki; Yachida, Tatsuo; Tani, Joji; Miyoshi, Hisaaki; Morishita, Asahiro; Masaki, Tsutomu

    2014-11-14

    To investigate the effects of gastric lavage with 2000 mL of saline in laparoscopic and endoscopic cooperative surgery. Twenty two patients who were diagnosed with a gastric gastrointestinal stromal tumor were enrolled. In former term, irrigations of the stomach were conducted whenever it was necessary, not systematically (Non systemic lavage group). In latter term, the stomach was thoroughly cleaned with 2000 mL of saline using an endoscope with a water jet, and Duodenal balloon occlusion was conducted to prevent refluxed bile and pancreatic juice (Systemic lavage+balloon occlusion group). The gastric wall was sprayed with 20 mL of distilled water, and 20 mL of gastric juice was collected in a sterile tube and submitted for culture. 20 mL of ascites was also collected from the laparoscopic ports and submitted for culture. We compared WBC, CRP, BT between two groups, and verify the reduction effect of bacterial counts in Systemic lavage+balloon occlusion group. WBC count before, 1 d after, and 3 d after laparoscopic and endoscopic cooperative surgery (LECS) were 5060 (95%CI: 4250-9640), 12140 (6050-14110), and 6910 (5320-12520) in Non systemic lavage group, 4400 (3660-7620), 8910 (6480-10980), and 5950 (4840-7860) in Systemic lavage+balloon occlusion group. Significant differences between two groups at the day after LECS (P = 0.029) and the 3 d after LECS (P = 0.042). CRP levels in Non systemic lavage group and in Systemic lavage+balloon occlusion group were significantly different at the day after LECS (P = 0.005) and the 3 d after LECS (P = 0.028). BTs (°C) in Non systemic lavage group and in Systemic lavage+balloon occlusion group were also significantly different at the day after LECS (P = 0.004) and the 3 d after LECS (P = 0.006). In a logarithmic comparison, bacterial load before gastric lavage, after lavage, and ascites culture were 6.08 (95%CI: 4.04-6.97), 0.48 (0-0.85), and 0.21 (0-0.56). The bacterial counts before and after gastric lavage were

  12. Concurrent performances: rate constancies without changeover delays1

    PubMed Central

    Catania, A. Charles

    1976-01-01

    Pigeons' pecks on two keys were maintained, without changeover delays, by independent variable-interval schedules of food reinforcement. Four regularly cycling 2-min components scheduled reinforcement respectively for both keys, left key only, both keys, and right key only. Initially, reinforcement scheduled for one key alone produced more responding on that key than reinforcement scheduled concurrently for both keys. Continued sessions reduced this difference; response rate on a given key approached constancy, or invariance with respect to the performance on and schedule for the other key. When extinction replaced the reinforcement schedule on either key, responding on that key decreased more during components that scheduled reinforcement for the other key than during those that did not. This demonstration that responses on one key were not supported by reinforcers on the other key suggested that the alternation of concurrent responding and either-key-alone responding prevented concurrent superstitions from developing. PMID:16811922

  13. 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

  14. Predictive Model Assessment for Count Data

    DTIC Science & Technology

    2007-09-05

    critique count regression models for patent data, and assess the predictive performance of Bayesian age-period-cohort models for larynx cancer counts...the predictive performance of Bayesian age-period-cohort models for larynx cancer counts in Germany. We consider a recent suggestion by Baker and...Figure 5. Boxplots for various scores for patent data count regressions. 11 Table 1 Four predictive models for larynx cancer counts in Germany, 1998–2002

  15. Single-photon counting for the 1300-1600-nm range by use of peltier-cooled and passively quenched InGaAs avalanche photodiodes.

    PubMed

    Rarity, J G; Wall, T E; Ridley, K D; Owens, P C; Tapster, P R

    2000-12-20

    We evaluate the performance of various commercially available InGaAs/InP avalanche photodiodes for photon counting in the infrared at temperatures that can be reached by Peltier cooling. We find that dark count rates are high, and this can partially saturate devices before optimum performance is achieved. At low temperatures the dark count rate rises because of a strong contribution from correlated afterpulses. We discuss ways of suppressing these afterpulses for different photon-counting applications.

  16. 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…

  17. Comparison of membrane filtration rates and hydrophobic grid membrane filter coliform and Escherichia coli counts in food suspensions using paddle-type and pulsifier sample preparation procedures.

    PubMed

    Sharpe, A N; Hearn, E M; Kovacs-Nolan, J

    2000-01-01

    Food suspensions prepared by Pulsifier contained less debris and filtered 1.3x to 12x faster through hydrophobic grid membrane filters (HGMFs) than those prepared by Stomacher 400. Coliform and Escherichia coli counts made by an HGMF method yielded 84 and 36 paired samples, respectively, positive by both suspending methods. Overall counts of pulsificates and stomachates did not differ significantly for either analysis, though coliform counts by Pulsifier were significantly higher in mushrooms and significantly lower in ground pork (P = 0.05). Regression equations for log10 counts of coliform and E. coli by Pulsifier and Stomacher were: Pulsifier = 0.12 + 0.97 x Stomacher, and Pulsifier = 0.01 + 1.01 x Stomacher, respectively.

  18. 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.

  19. 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.

  20. Analytical performance issues: comparison of ATP bioluminescence and aerobic bacterial count for evaluating surface cleanliness in an Italian hospital.

    PubMed

    Amodio, Emanuele; Cannova, Lucia; Villafrate, Maria Rosaria; Merendino, Anna Maria; Aprea, Luigi; Calamusa, Giuseppe

    2014-01-01

    Contaminated hospital surfaces have been demonstrated to be an important environmental reservoir of microorganisms that can increase the risk of nosocomial infection in exposed patients. As a consequence, cleaning and disinfecting hospital environments play an important role among strategies for preventing healthcare-associated colonization and infections. The aim of the present study was to evaluate whether adenosine triphosphate (ATP) presence, measured by bioluminescence methods, can predict microbiological contamination of hospital surfaces. The study was carried out between September and December 2012 at the University Hospital "P. Giaccone" of Palermo. A total of 193 randomly selected surfaces (tables, lockers, furnishings) were sampled and analyzed in order to assess ATP levels (expressed as relative light units or RLU) and aerobic colony count (ACC) or presence of S. aureus. ACC had median values of 1.85 cfu/cm(2)(interquartile range = 4.16) whereas ATP median was 44.6 RLU/cm(2)(interquartile range = 92.3). Overall, 85 (44.0%) surfaces exceeded the established microbial benchmark: 73 (37.8%) exceeded the 2.5 cfu/cm(2)ACC standard, 5 (2.6%) surfaces were positive for S. aureus and 7 (3.6%) showed both the presence of S. aureus and an ACC of more than 2.5 cfu/cm(2). ACC and bioluminescence showed significant differences in the different surface sites (p < 0.001). A significant correlation was found between ACC and RLU values (p-value < 0.001; R(2)= 0.29) and increasing RLU values were significantly associated with a higher risk of failing the benchmark (p < 0.001). Our data suggest that bioluminescence could help in measuring hygienic quality of hospital surfaces using a quick and sensitive test that can be an useful proxy of microbial contamination; however, further analysis will be necessary to assess the cost-efficacy of this methodology before requiring incorporation in hospital procedures.

  1. Has the Rate of CD4 Cell Count Decline before Initiation of Antiretroviral Therapy Changed over the Course of the Dutch HIV Epidemic among MSM?

    PubMed Central

    Gras, Luuk; Geskus, Ronald B.; Jurriaans, Suzanne; Bakker, Margreet; van Sighem, Ard; Bezemer, Daniela; Fraser, Christophe; Prins, Jan M.; Berkhout, Ben

    2013-01-01

    Introduction Studies suggest that the HIV-1 epidemic in the Netherlands may have become more virulent, leading to faster disease progression if untreated. Analysis of CD4 cell count decline before antiretroviral therapy (ART) initiation, a surrogate marker for disease progression, may be hampered by informative censoring as ART initiation is more likely with a steeper CD4 cell count decline. Methods Development of CD4 cell count from 9 to 48 months after seroconversion was analyzed using a mixed-effects model and 2 models that jointly modeled CD4 cell counts and time to censoring event (start ART, <100 CD4 cells/mm3, or AIDS) among therapy-naïve MSM HIV-1 seroconverters in the Netherlands. These models make different assumptions about the censoring process. Results All 3 models estimated lower median CD4 cell counts 9 months after seroconversion in later calendar years (623, 582, and 541 cells/mm3 for 1984–1995 [n = 111], 1996–2002 [n = 139], and 2003–2007 seroconverters [n = 356], respectively, shared-parameter model). Only the 2 joint-models found a trend for a steeper decline of CD4 cell counts with seroconversion in later calendar years (overall p-values 0.002 and 0.06 for the pattern-mixture and the shared-parameter model, respectively). In the shared-parameter model the median decline from 9 to 48 months was 276 cellsmm3 for 1984–1995 seroconverters and 308 cells/mm3 for 2003–2007 seroconverters (difference in slope, p = 0.045). Conclusion Mixed-effects models underestimate the CD4 cell decline prior to starting ART. Joint-models suggest that CD4 cell count declines more rapidly in patients infected between 2003 and 2007 compared to patients infected before 1996. PMID:23724048

  2. 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.

  3. The role of driver age in performance and attention allocation effects of roadway sign count, format and familiarity.

    PubMed

    Zahabi, Maryam; Machado, Patricia; Pankok, Carl; Lau, Mei Ying; Liao, Yi-Fan; Hummer, Joseph; Rasdorf, William; Kaber, David B

    2017-09-01

    White-on-blue logo signs are used to inform drivers of food, gas, lodging, and attraction businesses at highway interchanges. In this study, 60 drivers were asked to look for food and attraction targets on logo signs while driving in a realistic freeway simulation. The objective of the study was to quantify effects of the number of sign panels (six vs. nine), logo familiarity (familiar vs. unfamiliar), logo format (text vs. pictorial), and driver age (young, middle, and elderly) on performance, attention allocation and target identification accuracy. Results revealed elderly drivers to exhibit worse performance in comparison to middle-age and young groups even though they adopted a more conservative driving strategy. There was no significant effect of the number of panels, logo familiarity, and logo format on driver performance or attention allocation. In target identification, drivers were more accurate with familiar or text-based panels appearing in six-panel signs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. On-line Performance Assessment Using Rating Scales.

    ERIC Educational Resources Information Center

    Stahl, John; And Others

    On-line performance assessment was developed to maximize the usefulness of performance assessment and to minimize the time and labor costs incurred. This paper reports on the development of an on-line performance assessment instrument, focusing on the establishment and validation of the scoring rubric and its implementation in the Rasch model, the…

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  7. 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…

  8. 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…

  9. Leniency Bias in Performance Ratings: The Big-Five Correlates

    PubMed Central

    Cheng, Kevin H. C.; Hui, C. Harry; Cascio, Wayne F.

    2017-01-01

    Some researchers assume that employees' personality characteristics affect leniency in rating others and themselves. However, little research has investigated these two tendencies at the same time. In the present study we developed one index for other-rating leniency and another one for self-rating leniency. Based on a review of the literature, we hypothesized that a generous assessment of peers would more likely be made by those who are extroverted and agreeable than by those who are not. Furthermore, a generous assessment of oneself would more likely be made by people who are conscientious and emotionally stable, than by people who are not. We also investigated if the leniency in rating others and the leniency in rating oneself are part of a more general leniency tendency. Data collected from a sample of real estate dealers provided support for the above hypotheses. Limitations and implications for future research are discussed. PMID:28443043

  10. Counting and Comparing School Performance: An Analysis of Media Coverage of PISA in Australia, 2000-2014

    ERIC Educational Resources Information Center

    Baroutsis, Aspa; Lingard, Bob

    2017-01-01

    This paper empirically documents media portrayals of Australia's performance on the Program for the International Student Assessment (PISA), 2000-2014. We analyse newspaper articles from two national and eight metropolitan newspapers. This analysis demonstrates increased media coverage of PISA over the period in question. Our research data were…

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

    PubMed Central

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

    1977-01-01

    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

  12. 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.

  13. 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.

  14. Association of conception rate with pattern and level of somatic cell count elevation relative to time of insemination in dairy cows.

    PubMed

    Lavon, Y; Ezra, E; Leitner, G; Wolfenson, D

    2011-09-01

    The aim was to evaluate the effects of mastitis, determined by the pattern and level of somatic cell count (SCC) around first artificial insemination (AI), on conception rate (CR). Data from 287,192 first AI and milk records covering a 7-yr period were obtained from the Israeli Herd Book. Analyses examined the association of probability of conception with SCC elevation relative to timing of AI, using generalized linear mixed models. A SCC threshold of 150,000 cells/mL of milk was set to distinguish between uninfected cows and cows with mastitis. Accordingly, cows with high SCC before and low SCC after AI were designated cured, those with low SCC before and high SCC after AI were designated newly infected, and cows with high SCC before and after AI were designated chronic (likely subclinical) mastitic cows. Compared with uninfected cows, the cured, newly infected, and chronic subgroups showed reduced CR (39.4±0.1, 36.6±0.2, 32.9±0.3, and 31.5±0.2, respectively). In the chronic, subclinical group, probability of conception was lowered by 14.5% in the mild and moderately elevated SCC subgroups and by 20.5% in cows with high SCC elevation compared with the uninfected group (CR of 29.7 vs. 39.4%, respectively). A single high elevation of SCC (>10(6) cells/mL on only 1 milk test day) lowered the probability of conception by 23.6% when it occurred during the 10 d immediately before AI, but not when it occurred earlier. For 30 d after AI, probability of conception was lowered by about 23%, as reflected in a CR of about 27% compared with the uninfected group. Probability of conception was lowered in cows with uterine and foot health problems (33.9%), in multiparous cows (34.1%), and in cows in the summer (29.1%), but no interactions with mastitis were detected. Results indicate that SCC elevation around AI, typical for subclinical mastitis, was associated with a significant reduction in probability of conception, and that even mild SCC elevation reduced CR. Severe

  15. RBC count

    MedlinePlus

    ... RBCs contain hemoglobin , which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work. Watch this video about: Red blood cell production How the Test is Performed A blood sample ...

  16. Interpersonal Factors That Influence Principals' Rating of Teacher Performance.

    ERIC Educational Resources Information Center

    Bullock, William, Jr.; Davis, Joseph

    1985-01-01

    A study to determine whether principals are influenced by attraction factors in teacher evaluations found that principals are affected by nonperformance factors when they evaluate teacher performance. (MD)

  17. A Flexible System for Processing Clinical Performance Ratings: Illustrative Applications in a Residency and Four Clerkships.

    ERIC Educational Resources Information Center

    Cason, Gerald J.; And Others

    The Performance Rating portion of the University of Arkansas for Medical Sciences (UAMS) Objective Test Scoring and Performance Rating (OTS-PR) system is designed to help the clinical teacher evaluate students' clinical performance. The system collects, processes, and reports ratings of learners' performances in clinical settings. The system's 160…

  18. National Unmanned Aerial System Standardized Performance Testing and Rating (NUSTAR)

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal

    2016-01-01

    The overall objective of the NUSTAR Capability is to offer standardized tests and scenario conditions to assess performance of the UAS. The following are goals of the NU-STAR: 1. Create a prototype standardized tests and scenarios that vehicles can be tested against. 2. Identify key performance parameters of all UAS and their standardized measurement strategy. 3. Develop standardized performance reporting method (e.g., consumer report style) to assist prospective buyers. 4. Identify key performance metrics that could be used by judged towards overall safety of the UAS and operations. 5. If vehicle certification standard is made by a regulatory agency, the performance of individual UAS could be compared against the minimum requirement (e.g., sense and avoid detection time, stopping distance, kinetic energy, etc.).

  19. Carbohydrate counting of food.

    PubMed

    Hegar, Karin; Heiber, Stefanie; Brändle, Michael; Christ, Emanuel; Keller, Ulrich

    2011-07-07

    Carbohydrate counting is a principal strategy in nutritional management of type 1 diabetes. The Nutri-Learn buffet (NLB) is a new computer-based tool for patient instruction in carbohydrate counting. It is based on food dummies made of plastic equipped with a microchip containing relevant food content data. The tool enables the dietician to assess the patient's food counting abilities and the patient to learn in a hands-on interactive manner to estimate food contents such as carbohydrate content. Multicentre randomised controlled trial in 134 patients with type 1 diabetes comparing the use of the Nutri-Learn buffet in determining and improving ability to estimate the carbohydrate content of food with the use of conventional counselling tools (i.e. pictures and tables). The NLB group showed significantly better carbohydrate estimation values than the control group. In particular, there was a significant improvement in estimation of starches, fruits and sweets. The NLB was preferred by patients and dieticians in that rating of carbohydrate was closer to reality than the use of conventional tools, and since the tool has a play element, is interactive and adjustable, and can be used with only minimal knowledge of a specific language. Adjustment of preprandial insulin doses to the amounts of dietary carbohydrates ingested during the subsequent meal resulted in improved metabolic control in previous studies. The present study demonstrated that the new tool (Nutri-Learn buffet) improved teaching and learning of carbohydrate counting. In addition, it allowed an objective assessment of the carbohydrate counting skills of patients by the dietician. The findings therefore suggest that the tool is helpful in nutritional counselling of patients with diabetes mellitus.

  20. Lung counting: comparison of detector performance with a four detector array that has either metal or carbon fibre end caps, and the effect on mda calculation.

    PubMed

    Ahmed, Asm Sabbir; Hauck, Barry; Kramer, Gary H

    2012-08-01

    This study described the performance of an array of high-purity Germanium detectors, designed with two different end cap materials-steel and carbon fibre. The advantages and disadvantages of using this detector type in the estimation of the minimum detectable activity (MDA) for different energy peaks of isotope (152)Eu were illustrated. A Monte Carlo model was developed to study the detection efficiency for the detector array. A voxelised Lawrence Livermore torso phantom, equipped with lung, chest plates and overlay plates, was used to mimic a typical lung counting protocol with the array of detectors. The lung of the phantom simulated the volumetric source organ. A significantly low MDA was estimated for energy peaks at 40 keV and at a chest wall thickness of 6.64 cm.

  1. Rating Delay and Rating Outcomes in Laboratory-Based Performance Evaluations.

    DTIC Science & Technology

    1988-01-01

    accuracy over periods of 4" one week ( Heneman & Wexley, 1983; using the overall D-squared measure of accuracy) and no clear effect of rating delay for a...ratings of personality descriptors: The beholder’s eye . Personnel Psychology , 27, 409-421. Ilgen, D., & Favero, J. (1983). Methodological contributions

  2. 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…

  3. 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…

  4. 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…

  5. Performance Evaluation of High-Rate GPS Seismometers

    NASA Astrophysics Data System (ADS)

    Kato, T.; Ebinuma, T.

    2011-12-01

    High-rate GPS observations with higher than once-per-second sampling are getting increasingly important for seismology. Unlike a traditional seismometer which measures short period vibration using accelerometers, the GPS receiver can measure its antenna position directly and record long period seismic wave and permanent displacements as well. The high-rate GPS observations are expected to provide new insights in understanding the whole aspects of earthquake process. In this study, we investigated dynamic characteristics of the high-rate GPS receivers capable of outputting the observations at up to 50Hz. This higher output rate, however, doesn't mean higher dynamics range of the GPS observations. Since many GPS receivers are designed for low dynamics applications, such as static survey, personal and car navigation, the bandwidth of the loop filters tend to be narrower in order to reduce the noise level of the observations. The signal tracking loop works like a low-pass filter. Thus the narrower the bandwidth, the lower the dynamics range. In order to extend this dynamical limit, high-rate GPS receivers might use wider loop bandwidth for phase tracking. In this case, the GPS observations are degraded by higher noise level in return. In addition to the limitation of the loop bandwidth, higher acceleration due to earthquake may cause the steady state error in the signal tracking loop. As a result, kinematic solutions experience undesirable position offsets, or the receiver may lose the GPS signals in an extreme case. In order to examine those effects for the high-rate GPS observations, we made an experiment using a GPS signal simulator and several geodetic GPS receivers, including Trimble Net-R8, NovAtel OEMV, Topcon Net-G3A, and Javad SIGMA-G2T. We set up the zero-baseline simulation scenario in which the rover receiver was vibrating in a periodic motion with the frequency from 1Hz to 10Hz around the reference station. The amplitude of the motion was chosen to provide

  6. 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…

  7. 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.

  8. 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)

  9. Effects of Standard Extremity on Mixed Standard Scale Performance Ratings.

    DTIC Science & Technology

    1983-03-01

    affect the nature of performance ratins 1ei-ived from MSS responses and decisions based on M’S rat ings. 14Ieu h, ext rmit V 0 * standards was...experimental ly iani pulated , it was found thlat standard .extremity affects both tile level of performance rat inuis and the i)rolpor t i o • of logical ly...SIECURITY CLASSIFICATION OF THIS PAGE (When De4 &beter.f, SECURITY CLASSIFICATION OF THIS PAGE (w Daen V EnIreO0 extremity appears to affect the rankings on

  10. Performing ICSI with commercial microinjection pipettes enhanced pregnancy rates.

    PubMed

    Khalili, Mohammad Ali; Halvaei, Iman; Ghazali, Shahin; Razi, Mohammad Hossein

    2017-06-12

    Many technical factors can affect intracytoplasmic sperm injection (ICSI) outcomes. The role of the injection micropipette could be of vital importance in ICSI programs. The main goal was to compare ICSI pregnancy outcomes between commercial and home-made injection micropipettes in a large population with male factor infertility. Five-hundred and eleven ICSI cycles with severe male factor were included in this retrospective study. ICSI cycles were divided into two groups: A (home-made micropipettes, n = 267) and B (commercial micropipettes, n = 244). Rates of fertilization, embryo formation, and chemical and clinical pregnancies were compared between the groups. The independent samples t-test, chi-square test, and Fisher's exact test were used, whenever appropriate, for statistical analysis. A total of 3621 MII oocytes were retrieved, of which 2003 were fertilized. The rate of normal fertilization was significantly higher in group A (57.9%) compared to group B (52.5%). However, the rate of embryo formation showed an increase in group B compared to group A (90.4% and 85.9%, respectively, P = 0.002). In addition, the clinical pregnancy outcomes improved in group B. Our findings indicate that clinical pregnancy improves when commercial injection micropipettes are used in ICSI programs.

  11. 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…

  12. 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…

  13. Male and Female Performance in Ten Traditionally Male Navy Ratings.

    DTIC Science & Technology

    1982-02-01

    were doing work usually thought of as masculine even before World War 1, no data were collected on their performance. During World War 11, " Rosie the... Riveter " symbolized the thousands of women working in jobs that were then considered male occupations: aircraft assembler, sheet metal worker, truck

  14. 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.

  15. Trends in CD4 Count Testing, Retention in Pre-ART Care, and ART Initiation Rates over the First Decade of Expansion of HIV Services in Haiti

    PubMed Central

    Koenig, Serena P.; Bernard, Daphne; Dévieux, Jessy G.; Atwood, Sidney; McNairy, Margaret L.; Severe, Patrice; Marcelin, Adias; Julma, Pierrot; Apollon, Alexandra; Pape, Jean W.

    2016-01-01

    Background High attrition during the period from HIV testing to antiretroviral therapy (ART) initiation is widely reported. Though treatment guidelines have changed to broaden ART eligibility and services have been widely expanded over the past decade, data on the temporal trends in pre-ART outcomes are limited; such data would be useful to guide future policy decisions. Methods We evaluated temporal trends and predictors of retention for each step from HIV testing to ART initiation over the past decade at the GHESKIO clinic in Port-au-Prince Haiti. The 24,925 patients >17 years of age who received a positive HIV test at GHESKIO from March 1, 2003 to February 28, 2013 were included. Patients were followed until they remained in pre-ART care for one year or initiated ART. Results 24,925 patients (61% female, median age 35 years) were included, and 15,008 (60%) had blood drawn for CD4 count within 12 months of HIV testing; the trend increased over time from 36% in Year 1 to 78% in Year 10 (p<0.0001). Excluding transfers, the proportion of patients who were retained in pre-ART care or initiated ART within the first year after HIV testing was 84%, 82%, 64%, and 64%, for CD4 count strata ≤200, 201 to 350, 351 to 500, and >500 cells/mm3, respectively. The trend increased over time for each CD4 strata, and in Year 10, 94%, 95%, 79%, and 74% were retained in pre-ART care or initiated ART for each CD4 strata. Predictors of pre-ART attrition included male gender, low income, and low educational status. Older age and tuberculosis (TB) at HIV testing were associated with retention in care. Conclusions The proportion of patients completing assessments for ART eligibility, remaining in pre-ART care, and initiating ART have increased over the last decade across all CD4 count strata, particularly among patients with CD4 count ≤350 cells/mm3. However, additional retention efforts are needed for patients with higher CD4 counts. PMID:26901795

  16. 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 actually...

  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 actually...

  18. 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 actually...

  19. 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.

  20. The Watt Count System

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Watt Count System combines aerospace and computer technology, an engineering systems design approach and the environmental control expertise of a group of engineers who worked on Apollo. First step of the system is a computerized energy consumption analysis based on plans for a new home. Company calculates heating and cooling loads and customizes the most energy efficient system for the particular structure analyzed. A quality control engineer assures that insulation and ducting are installed to specifications. Analysis and design techniques are so accurate that company is able to give homeowner a two-year guarantee that the home's energy consumption will not exceed the kilowatt hour level determined by the computer in step one. In an annual energy performance comparison, a Watt Count home used 45 percent less energy than a conventionally equipped home.

  1. The Impact of Accelerated Promotion Rates on Drill Sergeant Performance

    DTIC Science & Technology

    2011-01-01

    wide range of behaviors and outcomes: student grade point averages, pharmacists ‘ job performance, Soldiers deployed on a peacekeeping mission... Training Doctrine Command, ―Sergeants as Drill Sergeants.‖ McCrae, R. R., & Costa, P. C., Jr. (1987). Validation of the five- factor model across...distribution: BARBARA A. BLACK, Ph.D. MICHELLE SAMS, Ph.D. Research Program Manager Director Training and Leader

  2. Pulse pileup statistics for energy discriminating photon counting x-ray detectors

    SciTech Connect

    Wang, Adam S.; Harrison, Daniel; Lobastov, Vladimir; Tkaczyk, J. Eric

    2011-07-15

    Purpose: Energy discriminating photon counting x-ray detectors can be subject to a wide range of flux rates if applied in clinical settings. Even when the incident rate is a small fraction of the detector's maximum periodic rate N{sub 0}, pulse pileup leads to count rate losses and spectral distortion. Although the deterministic effects can be corrected, the detrimental effect of pileup on image noise is not well understood and may limit the performance of photon counting systems. Therefore, the authors devise a method to determine the detector count statistics and imaging performance. Methods: The detector count statistics are derived analytically for an idealized pileup model with delta pulses of a nonparalyzable detector. These statistics are then used to compute the performance (e.g., contrast-to-noise ratio) for both single material and material decomposition contrast detection tasks via the Cramer-Rao lower bound (CRLB) as a function of the detector input count rate. With more realistic unipolar and bipolar pulse pileup models of a nonparalyzable detector, the imaging task performance is determined by Monte Carlo simulations and also approximated by a multinomial method based solely on the mean detected output spectrum. Photon counting performance at different count rates is compared with ideal energy integration, which is unaffected by count rate. Results: The authors found that an ideal photon counting detector with perfect energy resolution outperforms energy integration for our contrast detection tasks, but when the input count rate exceeds 20%N{sub 0}, many of these benefits disappear. The benefit with iodine contrast falls rapidly with increased count rate while water contrast is not as sensitive to count rates. The performance with a delta pulse model is overoptimistic when compared to the more realistic bipolar pulse model. The multinomial approximation predicts imaging performance very close to the prediction from Monte Carlo simulations. The

  3. Modeling and Simulation of Count Data

    PubMed Central

    Plan, E L

    2014-01-01

    Count data, or number of events per time interval, are discrete data arising from repeated time to event observations. Their mean count, or piecewise constant event rate, can be evaluated by discrete probability distributions from the Poisson model family. Clinical trial data characterization often involves population count analysis. This tutorial presents the basics and diagnostics of count modeling and simulation in the context of pharmacometrics. Consideration is given to overdispersion, underdispersion, autocorrelation, and inhomogeneity. PMID:25116273

  4. 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.

  5. 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.

  6. Monte Carlo Simulation of Counting Experiments.

    ERIC Educational Resources Information Center

    Ogden, Philip M.

    A computer program to perform a Monte Carlo simulation of counting experiments was written. The program was based on a mathematical derivation which started with counts in a time interval. The time interval was subdivided to form a binomial distribution with no two counts in the same subinterval. Then the number of subintervals was extended to…

  7. 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.

  8. Imaging performance of phase-contrast breast computed tomography with synchrotron radiation and a CdTe photon-counting detector.

    PubMed

    Sarno, A; Mettivier, G; Golosio, B; Oliva, P; Spandre, G; Di Lillo, F; Fedon, C; Longo, R; Russo, P

    2016-05-01

    Within the SYRMA-CT collaboration based at the ELETTRA synchrotron radiation (SR) facility the authors investigated the imaging performance of the phase-contrast computed tomography (CT) system dedicated to monochromatic in vivo 3D imaging of the female breast, for breast cancer diagnosis. Test objects were imaged at 38keV using monochromatic SR and a high-resolution CdTe photon-counting detector. Signal and noise performance were evaluated using modulation transfer function (MTF) and noise power spectrum. The analysis was performed on the images obtained with the application of a phase retrieval algorithm as well as on those obtained without phase retrieval. The contrast to noise ratio (CNR) and the capability of detecting test microcalcification clusters and soft masses were investigated. For a voxel size of (60μm)(3), images without phase retrieval showed higher spatial resolution (6.7mm(-1) at 10% MTF) than corresponding images with phase retrieval (2.5mm(-1)). Phase retrieval produced a reduction of the noise level and an increase of the CNR by more than one order of magnitude, compared to raw phase-contrast images. Microcalcifications with a diameter down to 130μm could be detected in both types of images. The investigation on test objects indicates that breast CT with a monochromatic SR source is technically feasible in terms of spatial resolution, image noise and contrast, for in vivo 3D imaging with a dose comparable to that of two-view mammography. Images obtained with the phase retrieval algorithm showed the best performance in the trade-off between spatial resolution and image noise. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  9. All about Carbohydrate Counting

    MedlinePlus

    Toolkit No. 14 All About Carbohydrate Counting What is carbohydrate counting? Carbohydrate counting is a way to plan your meals. It can help ... Diabetes Association, Inc. 2/14 Toolkit No. 14: All About Carbohydrate Counting continued The chart at the ...

  10. Can Ratio of Neutrophil-to-Lymphocyte Count and Erythrocyte Sedimentation Rate in Diabetic Foot Infecti on Predict Osteomyelitis and/or Amputation?

    PubMed Central

    Yapıcı, Oktay; Berk, Hande; Öztoprak, Nefise; Seyman, Derya; Tahmaz, Alper; Merdin, Alparslan

    2017-01-01

    The aim of this study was to search for any relations between the neutrophil-to-lymphocyte ratio (NLR) and the development of osteomyelitis and the need for amputation in patients with diabetic foot infection (DFI). All data included DFI patients who were hospitalized in our Infectious Diseases Clinic between 2012 and 2015 and who were classified according to International Classification Disease Code System. 75 patients were analyzed in the study. The DFI patients were stratified into 3 groups of whom had amputation procedure, whom had only debridement/drainage procedure and whom had any surgery procedure. Sidac post hoc analysis was used to perform the effects of NLR, C-reactive protein, erythrocyte sedimentation rate and glycosylated hemoglobin on the surgery procedure status. The DFI patients were also stratified into two another separate group for another analysis to search for the effect of NLR values on the development of osteomyelitis. The mean value of NLR in the amputated patients’ group (15.7±10.3 was significantly higher than those with debridement procedure (9.9±5.6) and those without any surgery (6.0±2.8) (P=0.001). NLR values were also found significantly higher in patients with osteomyelitis in the second analysis (P=0.004). In this study, the NLR was found to have a predictive value on the development of osteomyelitis and on the progression to amputation in patients with DFI. PMID:28286632

  11. Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

    NASA Astrophysics Data System (ADS)

    Gamboa, E. J.; Bachmann, B.; Kraus, D.; MacDonald, M. J.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Emig, J.; Ferguson, K. R.; Fletcher, L. B.; Glenzer, S. H.; Gorkhover, T.; Hau-Riege, S. P.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K.-H.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-08-01

    With the recent development of high-repetition rate x-ray free electron lasers (FEL), it is now possible to perform x-ray scattering and emission spectroscopy measurements from thin foils or gasses heated to high-energy density conditions by integrating over many experimental shots. Since the expected signal may be weaker than the typical CCD readout noise over the region-of-interest, it is critical to the success of this approach to use a detector with high-energy resolution so that single x-ray photons may be isolated. Here we describe a dual channel x-ray spectrometer developed for the Atomic and Molecular Optics endstation at the Linac Coherent Light Source (LCLS) for x-ray spectroscopy near the K-edge of aluminum. The spectrometer is based on a pair of curved PET (002) crystals coupled to a single pnCCD detector which simultaneously measures x-ray scattering and emission in the forward and backward directions. The signals from single x-ray photons are accumulated permitting continuous single-shot acquisition at 120 Hz.

  12. Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

    SciTech Connect

    Gamboa, E. J.; Bachmann, B.; Kraus, D.; MacDonald, M. J.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Emig, J.; Ferguson, K. R.; Fletcher, L. B.; Glenzer, S. H.; Gorkhover, T.; Hau-Riege, S. P.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K. -H.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-08-01

    The recent development of high-repetition rate x-ray free electron lasers (FEL), makes it possible to perform x-ray scattering and emission spectroscopy measurements from thin foils or gasses heated to high-energy density conditions by integrating over many experimental shots. Since the expected signal may be weaker than the typical CCD readout noise over the region-of-interest, it is critical to the success of this approach to use a detector with high-energy resolution so that single x-ray photons may be isolated. We describe a dual channel x-ray spectrometer developed for the Atomic and Molecular Optics endstation at the Linac Coherent Light Source (LCLS) for x-ray spectroscopy near the K-edge of aluminum. The spectrometer is based on a pair of curved PET (002) crystals coupled to a single pnCCD detector which simultaneously measures x-ray scattering and emission in the forward and backward directions. Furthermore, the signals from single x-ray photons are accumulated permitting continuous single-shot acquisition at 120 Hz.

  13. Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

    DOE PAGES

    Gamboa, E. J.; Bachmann, B.; Kraus, D.; ...

    2016-08-01

    The recent development of high-repetition rate x-ray free electron lasers (FEL), makes it possible to perform x-ray scattering and emission spectroscopy measurements from thin foils or gasses heated to high-energy density conditions by integrating over many experimental shots. Since the expected signal may be weaker than the typical CCD readout noise over the region-of-interest, it is critical to the success of this approach to use a detector with high-energy resolution so that single x-ray photons may be isolated. We describe a dual channel x-ray spectrometer developed for the Atomic and Molecular Optics endstation at the Linac Coherent Light Source (LCLS)more » for x-ray spectroscopy near the K-edge of aluminum. The spectrometer is based on a pair of curved PET (002) crystals coupled to a single pnCCD detector which simultaneously measures x-ray scattering and emission in the forward and backward directions. Furthermore, the signals from single x-ray photons are accumulated permitting continuous single-shot acquisition at 120 Hz.« less

  14. Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

    SciTech Connect

    Gamboa, E. J.; Bachmann, B.; Kraus, D.; MacDonald, M. J.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Emig, J.; Ferguson, K. R.; Fletcher, L. B.; Glenzer, S. H.; Gorkhover, T.; Hau-Riege, S. P.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K. -H.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-08-01

    The recent development of high-repetition rate x-ray free electron lasers (FEL), makes it possible to perform x-ray scattering and emission spectroscopy measurements from thin foils or gasses heated to high-energy density conditions by integrating over many experimental shots. Since the expected signal may be weaker than the typical CCD readout noise over the region-of-interest, it is critical to the success of this approach to use a detector with high-energy resolution so that single x-ray photons may be isolated. We describe a dual channel x-ray spectrometer developed for the Atomic and Molecular Optics endstation at the Linac Coherent Light Source (LCLS) for x-ray spectroscopy near the K-edge of aluminum. The spectrometer is based on a pair of curved PET (002) crystals coupled to a single pnCCD detector which simultaneously measures x-ray scattering and emission in the forward and backward directions. Furthermore, the signals from single x-ray photons are accumulated permitting continuous single-shot acquisition at 120 Hz.

  15. 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…

  16. 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 μm. It can operate both in single photon counting (SPC) mode and in C8P1 mode. In SPC the measured ENC is 84 erms (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.

  17. 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

  18. Exposure reduces negative bias in self-rated performance in public speaking fearful participants.

    PubMed

    Cheng, Joyce; Niles, Andrea N; Craske, Michelle G

    2017-03-01

    Individuals with public speaking anxiety (PSA) under-rate their performance compared to objective observers. The present study examined whether exposure reduces the discrepancy between self and observer performance ratings and improved observer-rated performance in individuals with PSA. PSA participants gave a speech in front of a small audience and rated their performance using a questionnaire before and after completing repeated exposures to public speaking. Non-anxious control participants gave a speech and completed the questionnaire one time only. Objective observers watched videos of the speeches and rated performance using the same questionnaire. PSA participants underrated their performance to a greater degree than did controls prior to exposure, but also performed significantly more poorly than did controls when rated objectively. Bias significantly decreased and objective-rated performance significantly increased following completion of exposure in PSA participants, and on one performance measure, anxious participants no longer showed a greater discrepancy between self and observer performance ratings compared to controls. The study employed non-clinical student sample, but the results should be replicated in clinical anxiety samples. These findings indicate that exposure alone significantly reduces negative performance bias among PSA individuals, but additional exposure or additional interventions may be necessary to fully correct bias and performance deficits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Diagnostic test performance of somatic cell count, lactate dehydrogenase, and N-acetyl-β-D-glucosaminidase for detecting dairy cows with intramammary infection.

    PubMed

    Nyman, A-K; Emanuelson, U; Waller, K Persson

    2016-02-01

    The main objective of this study was to investigate the diagnostic test performance of somatic cell count (SCC), lactate dehydrogenase (LDH), and N-acetyl-β-D-glucosaminidase (NAGase), analyzed in composite test milking samples, for detecting dairy cows with or without intramammary infection (IMI). A second objective was to investigate whether an adjustment of these udder health indicators according to their associations with different influential factors (i.e., parity, days in milk, and season) improved their test performance. Moreover, we wanted to investigate whether test performance of SCC improved if SCC results from previous adjacent test milkings were included in the model. Such test milking data were not available for LDH or NAGase. In this cross-sectional study, quarter milk samples for bacteriological examination were taken from almost 1,000 cows from 25 dairy herds during 3 consecutive days: the day before test milking, the day of test milking, and the day after test milking. From each cow, a composite test milking sample was analyzed for milk composition, SCC, LDH, and NAGase. Among the cows sampled, 485 were IMI negative and 256 were IMI positive in one or more udder quarters according to the definitions used. The remaining cows had inconclusive IMI status. To assess the test performance of SCC, LDH, and NAGase to identify IMI-negative and IMI-positive cows, univariable generalized estimating equation models were used with the udder health indicator of interest as outcome and IMI status as explanatory variable. From these models, receiver-operator characteristic curves were created and the area under cure (AUC) was calculated. From each model, a cut-off was chosen for calculations of the sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) for each udder health indicator. The AUC was similar for the adjusted SCC (0.84), nonadjusted SCC (0.83) and geometric mean SCC (0.80-0.81), but

  20. Relationships between chewing rate, occlusion, cephalometric anatomy, muscle activity, and masticatory performance.

    PubMed

    Fulks, Brent A; Callaghan, Kathryn X; Tewksbury, Claire D; Gerstner, Geoffrey E

    2017-11-01

    Mastication consists of rhythmic jaw openings and closings. Recent studies suggest that muscle mechanical properties determine the rhythmic rate; however, speed-accuracy tradeoffs may also play a role. This study evaluated how variation in chewing rate affected chewing performance, how masticatory muscle activity varied with chewing rate, and whether morphology and demographics contributed to performance. Chewing performance and muscle activity were sampled in 23 healthy, fully-dentate adults, who chewed a standardized test food to a metronome set at 0.5, 0.75, 1, 2 and 3 times their 'natural' chewing rates. Subjects produced ten chews per trial, and five trials for each of the five rates. Surface electromyographic (EMG) activity was sampled from masseter and temporalis muscles bilaterally. Demographic, occlusal, and cephalometric data were also obtained. Chewing performance, defined by median particle size, was inversely related to chewing rate; however, performance was not remarkably improved at rates slower than the natural chewing rate. Above the natural chewing rate, variability in EMG bursts diminished, suggesting a reduction in muscle activity modulation at fast rates. Occlusal contacts and most morphological features appeared to play a limited or no role in performance. Results support the hypothesis that the 'natural' chewing rate is selected to be as fast as possible while providing sufficient time to allow EMG modulation for improved performance. The interplay between EMG modulation and individual variation in skeletal morphology is likely critical for optimal chewing performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... be rated troubled. (d) Modified rating on an indicator. A rating on any of the indicators at §§ 985.3... information that the PHA's SEMAP certification concerning an indicator is not accurate. (e) Modified or... overall performance rating when warranted by circumstances which have bearing on the SEMAP indicators such...

  2. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... be rated troubled. (d) Modified rating on an indicator. A rating on any of the indicators at §§ 985.3... information that the PHA's SEMAP certification concerning an indicator is not accurate. (e) Modified or... overall performance rating when warranted by circumstances which have bearing on the SEMAP indicators such...

  3. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... be rated troubled. (d) Modified rating on an indicator. A rating on any of the indicators at §§ 985.3... information that the PHA's SEMAP certification concerning an indicator is not accurate. (e) Modified or... overall performance rating when warranted by circumstances which have bearing on the SEMAP indicators such...

  4. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... be rated troubled. (d) Modified rating on an indicator. A rating on any of the indicators at §§ 985.3... information that the PHA's SEMAP certification concerning an indicator is not accurate. (e) Modified or... overall performance rating when warranted by circumstances which have bearing on the SEMAP indicators such...

  5. 24 CFR 985.103 - SEMAP score and overall performance rating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... be rated troubled. (d) Modified rating on an indicator. A rating on any of the indicators at §§ 985.3... information that the PHA's SEMAP certification concerning an indicator is not accurate. (e) Modified or... overall performance rating when warranted by circumstances which have bearing on the SEMAP indicators such...

  6. Current performance of planter technology to support variable-rate seeding in the Southern US

    USDA-ARS?s Scientific Manuscript database

    Advances in planting technology are expanding opportunities to vary seeding rates on–the-go. Variable-rate seeding can help maximize overall profits by matching optimal planting rates to field production variability. An important aspect of variable-rate seeding is ensuring peak performance of the pl...

  7. 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.

  8. 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.

  9. Forbush effects in total neutron monitor counting rate and neutron multiplicities recorded by the 6NM-64 of the E. Segre' Observatory at 2025 m and by the Rome 17NM-64

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.

    We show some Forbush-decrease events by using 5-minute and 1-hourly data of total neutron monitor counting rate and of detected neutron multiplicities according to observations by the Emilio Segre' Observatory 6NM-64 at the height of 2025 m (Rc=10.8 GV) and by the Rome 17NM-64 neutron monitor (Rc=6.2 GV). By these data it is possible in principle to evaluate approximately the cosmic ray primary variations for each Forbush-decrease (by using the method of coupling functions); also the detected neutron multiplicities can provide additional important information.

  10. 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.

  11. 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)

  12. 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)

  13. Fermentative and growth performances of Dekkera bruxellensis in different batch systems and the effect of initial low cell counts in co-cultures with Saccharomyces cerevisiae.

    PubMed

    Meneghin, Maria Cristina; Bassi, Ana Paula Guarnieri; Codato, Carolina Brito; Reis, Vanda Renata; Ceccato-Antonini, Sandra Regina

    2013-08-01

    Dekkera bruxellensis is a multifaceted yeast present in the fermentative processes used for alcoholic beverage and fuel alcohol production - in the latter, normally regarded as a contaminant. We evaluated the fermentation and growth performance of a strain isolated from water in an alcohol-producing unit, in batch systems with/without cell recycling in pure and co-cultures with Saccharomyces cerevisiae. The ethanol resistance and aeration dependence for ethanol/acid production were verified. Ethanol had an effect on the growth of D. bruxellensis in that it lowered or inhibited growth depending on the concentration. Acid production was verified in agitated cultures either with glucose or sucrose, but more ethanol was produced with glucose in agitated cultures. Regardless of the batch system, low sugar consumption and alcohol production and expressive growth were found with D. bruxellensis. Despite a similar ethanol yield compared to S. cerevisiae in the batch system without cell recycling, ethanol productivity was approximately four times lower. However, with cell recycling, ethanol yield was almost half that of S. cerevisiae. At initial low cell counts of D. bruxellensis (10 and 1000 cells/ml) in co-cultures with S. cerevisiae, a decrease in fermentative efficiency and a substantial growth throughout the fermentative cycles were displayed by D. bruxellensis. Due to the peculiarity of cell repitching in Brazilian fermentation processes, D. bruxellensis is able to establish itself in the process, even when present in low numbers initially, substantially impairing bioethanol production due to the low ethanol productivity, in spite of comparable ethanol yields. Copyright © 2013 John Wiley & Sons, Ltd.

  14. 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.

  15. 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

  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. 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.…

  19. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Required actions for PHA with... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1) Required...-site review of PHA program management for any PHA assigned an overall performance rating of troubled to...

  20. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Required actions for PHA with... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1) Required...-site review of PHA program management for any PHA assigned an overall performance rating of troubled to...

  1. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Required actions for PHA with... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1) Required...-site review of PHA program management for any PHA assigned an overall performance rating of troubled to...

  2. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Required actions for PHA with... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1) Required...-site review of PHA program management for any PHA assigned an overall performance rating of troubled to...

  3. 24 CFR 985.107 - Required actions for PHA with troubled performance rating.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Required actions for PHA with... § 985.107 Required actions for PHA with troubled performance rating. (a) On-site reviews—(1) Required...-site review of PHA program management for any PHA assigned an overall performance rating of troubled to...

  4. 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.…

  5. 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…

  6. 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…

  7. 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…

  8. 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.

  9. 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.

  10. 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…

  11. 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…

  12. Grad Rates Don't Tell Full Story of Community College Performance

    ERIC Educational Resources Information Center

    Sbrega, John J.

    2012-01-01

    Anyone who fixates on graduation rates has little understanding not only of the rich mission and value of community colleges, but also how deeply flawed and inadequate those rates are as a principal assessment tool for the performance of community colleges. In this article, the author discusses what is wrong with the use of graduation rates as the…

  13. 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.

  14. Rewarded remembering: dissociations between self-rated motivation and memory performance.

    PubMed

    Ngaosuvan, Leonard; Mäntylä, Timo

    2005-08-01

    People often claim that they perform better in memory performance tasks when they are more motivated. However, past research has shown minimal effects of motivation on memory performance when factors contributing to item-specific biases during encoding and retrieval are taken into account. The purpose of the present study was to examine the generality of this apparent dissociation by using more sensitive measures of experienced motivation and memory performance. Extrinsic motivation was manipulated through competition instructions, and subjective ratings of intrinsic and extrinsic motivation were obtained before and after study instructions. Participants studied a series of words, and memory performance was assessed by content recall (Experiment 1) and source recall (Experiment 2). Both experiments showed dissociation between subjective ratings of extrinsic motivation and actual memory performance, so that competition increased self-rated extrinsic motivation but had no effects on memory performance, including source recall. Inconsistent with most people's expectations, the findings suggest that extrinsic motivation has minimal effects on memory performance.

  15. Maryland Kids Count Factbook, 2001.

    ERIC Educational Resources Information Center

    Advocates for Children and Youth, Baltimore, MD.

    This 7th annual Kids Count Factbook provides information on trends in the well-being of children in Maryland and its 24 jurisdictions. The statistical portrait is based on 18 indicators of well-being: (1) low birth-weight infants; (2) infant mortality; (3) early prenatal care; (4) binge drinking; (5) child deaths; (6) child injury rate; (7) grade…

  16. Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

    PubMed

    Zeh, Clement; Rose, Charles E; Inzaule, Seth; Desai, Mitesh A; Otieno, Fredrick; Humwa, Felix; Akoth, Benta; Omolo, Paul; Chen, Robert T; Kebede, Yenew; Samandari, Taraz

    2017-09-01

    CD4+ T-lymphocyte count testing at the point-of-care (POC) may improve linkage to care of persons diagnosed with HIV-1 infection, but the accuracy of POC devices when operated by lay-counselors in the era of task-shifting is unknown. We examined the accuracy of Alere's Pima™ POC device on both capillary and venous blood when performed by lay-counselors and laboratory technicians. In Phase I, we compared the perfomance of POC against FACSCalibur™ for 280 venous specimens by laboratory technicians. In Phase II we compared POC performance by lay-counselors versus laboratory technicians using 147 paired capillary and venous specimens, and compared these to FACSCalibur™. Statistical analyses included Bland-Altman analyses, concordance correlation coefficient, sensitivity, and specificity at treatment eligibility thresholds of 200, 350, and 500cells/μl. Phase I: POC sensitivity and specificity were 93.0% and 84.1% at 500cells/μl, respectively. Phase II: Good agreement was observed for venous POC results from both lay-counselors (concordance correlation coefficient (CCC)=0.873, bias -86.4cells/μl) and laboratory technicians (CCC=0.920, bias -65.7cells/μl). Capillary POC had good correlation: lay-counselors (CCC=0.902, bias -71.2cells/μl), laboratory technicians (CCC=0.918, bias -63.0cells/μl). Misclassification at the 500 cells/μl threshold for venous blood was 13.6% and 10.2% for lay-counselors and laboratory technicians and 12.2% for capillary blood in both groups. POC tended to under-classify the CD4 values with increasingly negative bias at higher CD4 values. Pima™ results were comparable to FACSCalibur™ for both venous and capillary specimens when operated by lay-counselors. POC CD4 testing has the potential to improve linkage to HIV care without burdening laboratory technicians in resource-limited settings. Published by Elsevier B.V.

  17. Effects of Rating Delay and True Halo in Laboratory-Based Performance Evaluations,

    DTIC Science & Technology

    1987-01-01

    true halo (i.e., the median intercorrelations among criterion scores on the performance dimensions ) were examined for effects on rater errors, rater...evaluated by multiple ’ sets of raters, true intercorrelation among the rating dimensions (i.e., true halo) becomes a variable and its effects on rating...based ratings such that correlations between rated dimensions occur in the direction of the implicit covariance theory (IMT) of the rater (Borman, 1983

  18. 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.

  19. Reliability of the total lymphocyte count as a parameter of nutrition.

    PubMed

    Forse, R A; Rompre, C; Crosilla, P; O-Tuitt, D; Rhode, B; Shizgal, H M

    1985-05-01

    To evaluate the total lymphocyte count as a means of nutritional assessment, body composition studies (a proven method of nutritional assessment) and total lymphocyte determinations were performed simultaneously in 153 patients. The total lymphocyte count correlated poorly with both the body cell mass and the nutritional state measured by the Nae to Ke ratio. For diagnosing malnutrition, the total lymphocyte count had a false-positive rate of 34% and a false-negative rate of 50%. In a group of 78 patients who received total parenteral nutrition for 2 weeks, the total lymphocyte count did not accurately reflect the nutritional changes. Due to its poor sensitivity and specificity, the total lymphocyte count is of no value as a measure of the nutritional state.

  20. Material screening with HPGe counting station for PandaX experiment

    NASA Astrophysics Data System (ADS)

    Wang, X.; Chen, X.; Fu, C.; Ji, X.; Liu, X.; Mao, Y.; Wang, H.; Wang, S.; Xie, P.; Zhang, T.

    2016-12-01

    A gamma counting station based on high-purity germanium (HPGe) detector was set up for the material screening of the PandaX dark matter experiments in the China Jinping Underground Laboratory. Low background gamma rate of 2.6 counts/min within the energy range of 20 to 2700 keV is achieved due to the well-designed passive shield. The sentivities of the HPGe detetector reach mBq/kg level for isotopes like K, U, Th, and even better for Co and Cs, resulted from the low-background rate and the high relative detection efficiency of 175%. The structure and performance of the counting station are described in this article. Detailed counting results for the radioactivity in materials used by the PandaX dark-matter experiment are presented. The upgrading plan of the counting station is also discussed.

  1. Self-Ratings of Past, Present, and Future Cognitive Performance across Adulthood.

    ERIC Educational Resources Information Center

    Fingerman, Karen L.; Perlmutter, Marion

    1994-01-01

    Examined age differences in self-ratings of present and projected past and future cognitive performance across cognitive domains. Findings from 151 adults in their 20s, 40s, 60s, and 80s revealed that performance on fluid/speeded intelligence, memory, and reasoning tasks followed progression of poorer performance with age. Found age differences in…

  2. 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…

  3. 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…

  4. Photon counting computed tomography: concept and initial results.

    PubMed

    Shikhaliev, Polad M; Xu, Tong; Molloi, Sabee

    2005-02-01

    A concept of a photon counting cone beam CT is proposed. The system uses a new Multi Slit Multi Slice (MSMS) cone beam acquisition geometry utilizing a linear array photon counting detectors. The MSMS cone beam acquisition is a direct analogy of the scanning multislit acquisition used in projection x-ray imaging. This geometry provides a CT imaging with dose efficient scatter rejection and allows for using available photon counting detectors. The microchannel plate (MCP) detector is proposed as a linear array photon counting detector for MSMS cone beam CT system. Initial testing of the MCP detector for CT application was performed. The field of view of the prototype MCP detector is 60 mm. A delay line position encoding electronics was used. The electronics has a single channel input for evaluation of events from the entire detector field of view. This limits the system count rate at 2 x 10(5) count/s. The spatial resolution of this detector is 80 microm FWHM at 40 kVp and 200 microm FWHM at 90 kVp tube voltages. The detector noise in CT projections is less than 1 count/pixel for the 80 microm pixel size. The CT projections contain quantum-limited and scatter free signal. Images of a contrast phantom and a small animal were acquired at 50 kVp and 80 kVp tube voltages. The CT numbers for different contrast elements were calculated for a given x-ray spectrum and compared with experimental values. The quantum efficiency of the current detector is 56% at 90 kVp, which is suboptimal because of the large channel diameter (25 microm) of these MCPs. The MCPs with smaller channels and higher efficiencies are being tested. The quantum efficiency was measured to be 70% for a new MCP with 5 microm channel diameter. Design parameters of a clinically applicable photon counting MSMS cone beam CT for breast imaging was evaluated. System uses 20 cm field of view MCP detectors based on 5 microm channel MCPs and high count rate ASIC electronics. It was concluded that the MSMS cone

  5. 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)…

  6. 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)…

  7. Adaptive rate selection scheme for video transmission to resolve IEEE 802.11 performance anomaly

    NASA Astrophysics Data System (ADS)

    Tang, Guijin; Zhu, Xiuchang

    2011-10-01

    Multi-rate transmission may lead to performance anomaly in an IEEE 802.11 network. It will decrease the throughputs of all the higher rate stations. This paper proposes an adaptive rate selection scheme for video service when performance anomaly occurs. Considering that video has the characteristic of tolerance to packet loss, we actively drop several packets so as to select the rates as high as possible for transmitting packets. Experiment shows our algorithm can decrease the delay and jitter of video, and improve the system throughput as well.

  8. Recurrence rates and clinical outcome for dogs with grade II mast cell tumours with a low AgNOR count and Ki67 index treated with surgery alone.

    PubMed

    Smith, J; Kiupel, M; Farrelly, J; Cohen, R; Olmsted, G; Kirpensteijn, J; Brocks, B; Post, G

    2017-03-01

    Grade II mast cell tumours (MCT) are tumours with variable biologic behaviour. Multiple factors have been associated with outcome, including proliferation markers. The purpose of this study was to determine if extent of surgical excision affects recurrence rate in dogs with grade II MCT with low proliferation activity, determined by Ki67 and argyrophilic nucleolar organising regions (AgNOR). Eighty-six dogs with cutaneous MCT were evaluated. All dogs had surgical excision of their MCT with a low Ki67 index and combined AgNORxKi67 (Ag67) values. Twenty-three (27%) dogs developed local or distant recurrence during the median follow-up time. Of these dogs, six (7%) had local recurrence, one had complete and five had incomplete histologic margins. This difference in recurrence rates between dogs with complete and incomplete histologic margins was not significant. On the basis of this study, ancillary therapy may not be necessary for patients with incompletely excised grade II MCT with low proliferation activity.

  9. Pretreatment platelet count improves the prognostic performance of the TNM staging system and aids in planning therapeutic regimens for nasopharyngeal carcinoma: a single-institutional study of 2,626 patients.

    PubMed

    Chen, Yu-Pei; Zhao, Bing-Cheng; Chen, Chen; Shen, Lu-Jun; Gao, Jin; Mai, Zhuo-Yao; Chen, Meng-Kun; Chen, Gang; Yan, Fang; Liu, Su; Xia, Yun-Fei

    2015-03-05

    Thrombocytosis has been identified as an unfavorable prognostic factor in several types of cancer. This study aimed to evaluate the prognostic value of pretreatment platelet count in association with the TNM staging system and therapeutic regimens in patients with nasopharyngeal carcinoma (NPC). A total of 2,626 patients with NPC were retrospectively analyzed. Platelet count >300 × 10(9)/L was defined as thrombocytosis. Matched-pair analysis was performed between patients receiving chemoradiotherapy and radiotherapy. Multivariate analysis showed that platelet count was an independent unfavorable prognostic factor for overall survival (OS) [hazard ratio (HR) = 1.810, 95% confidence interval (CI) = 1.531-2.140, P < 0.001] and distant metastasis-free survival (DMFS) (HR = 1.873, 95% CI = 1.475-2.379, P < 0.001) in the entire patient cohort. Further subgroup analysis revealed that increased platelet count was an independent unfavorable prognostic factor for OS and DMFS in patients with NPC stratified by early and advanced T category, N category, or TNM classification (all P ≤ 0.001). Receiver operating characteristic (ROC) curves verified that the predictive value of TNM classification for OS was improved when combined with pretreatment platelet count (P = 0.030). Matched-pair analysis showed that chemoradiotherapy significantly improved OS only in advanced-stage NPC with thrombocytosis (HR = 0.416, 95% CI = 0.226-0.765, P = 0.005). Pretreatment platelet count, when combined with TNM classification, is a useful indicator for metastasis and survival in patients with NPC. It may improve the predictive value of the TNM classification and help to identify patients likely to benefit from more aggressive therapeutic regimens.

  10. 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

  11. A high count rate one-dimensional position sensitive detector and a data acquisition system for time resolved X-ray scattering studies

    NASA Astrophysics Data System (ADS)

    Pernot, P.; Kahn, R.; Fourme, R.; Leboucher, P.; Million, G.; Santiard, J. C.; Charpak, G.

    1982-10-01

    A curved multiwire proportional drift chamber has been built as a general purpose instrument for X-ray scattering and X-ray diffraction experiments with synchrotron radiation. This parallax-free one-dimensional linear position sensitive detector has a parallel readout with a double hit logic. The data acquisition system, installed as a part of the D11 camera at LURE-DCI, is designed to perform time slicing and cyclic experiments; it has been used with either the fast multiwire chamber or a standard position sensitive detector with delay line readout.

  12. Community pharmacy owners' views of star ratings and performance measurement: In-depth interviews.

    PubMed

    Teeter, Benjamin S; Fox, Brent I; Garza, Kimberly B; Harris, Stanley G; Nau, David P; Owensby, Justin K; Westrick, Salisa C

    2016-01-01

    The star rating system implemented by Medicare has the potential to positively affect patient health and may have financial implications for community pharmacies. Learning from owners of community pharmacies with high performance on these quality measures may help us to identify and further understand factors contributing to their success. This study described high-performing community pharmacy owners' current awareness and knowledge of star ratings, attitudes toward star ratings and performance measurement, and initiatives being offered in pharmacies that aim to improve the quality of care. Qualitative interviews with owners of independent community pharmacies were conducted in Spring 2015. Fifteen community pharmacies with high performance on the star rating measures were invited to participate. Recruitment did not end until the saturation point had been reached. All interviews were transcribed verbatim. Interview data were analyzed with the use of ATLAS.ti by 2 coders trained in thematic analysis. Krippendorf's alpha was calculated to assess intercoder reliability. Ten high-performing pharmacy owners participated. Analysis identified 8 themes, which were organized into the following categories: 1) current awareness and knowledge (i.e., superficial or advanced knowledge); 2) attitudes toward star ratings (positive perceptions, skeptical of performance rewards, and lack a feeling of control); and 3) pharmacy initiatives (personal patient relationships, collaborative employee relationships, and use of technology). Intercoder reliability was good overall. Interviews with high-performing pharmacies suggested that awareness of the star rating measures, overall positive attitudes toward the star ratings, the relationships that pharmacy owners have with their patients and their employees, and the use of technology as a tool to enhance patient care may contribute to high performance on the star rating measures. Future research is needed to determine if and how these

  13. 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.

  14. White blood cell counts: reference methodology.

    PubMed

    Chabot-Richards, Devon S; George, Tracy I

    2015-03-01

    Modern hematology laboratories use automated hematology analyzers to perform cell counts. These instruments provide accurate, precise, low-cost differential counts with fast turnaround times. Technologies commonly used include electrical impedance, radiofrequency conductivity, laser light scattering, and cytochemistry. This article reviews the principles of these methodologies and possible sources of error, provides guidance for selecting flagging criteria, and discusses novel, clinically relevant white blood cell parameters provided by new instruments, including immature granulocyte count and granularity index.

  15. 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

  16. 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.

  17. 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).

  18. Hospital Evaluations by Social Media: A Comparative Analysis of Facebook Ratings among Performance Outliers.

    PubMed

    Glover, McKinley; Khalilzadeh, Omid; Choy, Garry; Prabhakar, Anand M; Pandharipande, Pari V; Gazelle, G Scott

    2015-10-01

    An increasing number of hospitals and health systems utilize social media to allow users to provide feedback and ratings. The correlation between ratings on social media and more conventional hospital quality metrics remains largely unclear, raising concern that healthcare consumers may make decisions on inaccurate or inappropriate information regarding quality. The purpose of this study was to examine the extent to which hospitals utilize social media and whether user-generated metrics on Facebook(®) correlate with a Hospital Compare(®) metric, specifically 30-day all cause unplanned hospital readmission rates. This was a retrospective cross-sectional study conducted among all U.S. hospitals performing outside the confidence interval for the national average on 30-day hospital readmission rates as reported on Hospital Compare. Participants were 315 hospitals performing better than U.S. national rate on 30-day readmissions and 364 hospitals performing worse than the U.S. national rate. The study analyzed ratings of hospitals on Facebook's five-star rating scale, 30-day readmission rates, and hospital characteristics including beds, teaching status, urban vs. rural location, and ownership type. Hospitals performing better than the national average on 30-day readmissions were more likely to use Facebook than lower-performing hospitals (93.3 % vs. 83.5 %; p < 0.01). The average rating for hospitals with low readmission rates (4.15 ± 0.31) was higher than that for hospitals with higher readmission rates (4.05 ± 0.41, p < 0.01). Major teaching hospitals were 14.3 times more likely to be in the high readmission rate group. A one-star increase in Facebook rating was associated with increased odds of the hospital belonging to the low readmission rate group by a factor of 5.0 (CI: 2.6-10.3, p <  0.01), when controlling for hospital characteristics and Facebook-related variables. Hospitals with lower rates of 30-day hospital-wide unplanned readmissions have

  19. Guidance on the use of handheld 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

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

    2012-03-01

    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--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 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

  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

    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