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Sample records for continuous position sensitive

  1. CONTINUOUSLY SENSITIVE BUBBLE CHAMBER

    DOEpatents

    Good, R.H.

    1959-08-18

    A radiation detector of the bubble chamber class is described which is continuously sensitive and which does not require the complex pressure cycling equipment characteristic of prior forms of the chamber. The radiation sensitive element is a gas-saturated liquid and means are provided for establishing a thermal gradient across a region of the liquid. The gradient has a temperature range including both the saturation temperature of the liquid and more elevated temperatures. Thus a supersaturated zone is created in which ionizing radiations may give rise to visible gas bubbles indicative of the passage of the radiation through the liquid. Additional means are provided for replenishing the supply of gas-saturated liquid to maintaincontinuous sensitivity.

  2. Position Sensitive Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Sadleir, J. E.; Hammock, C.; Figueroa-Feliciano, E.; Stahle, C. K.; Bandler, S.; Saab, T.; Lindeman, M.; Porter, F. S.; Chervenak, J.; Brown, G.

    2004-01-01

    A Position Sensitive Transition-Edge Sensor (PoST) is a microcalorimeter device capable of one-dimensional imaging spectroscopy. The device consists of two Transition-Edge Sensors (TESs) connected to the ends of a long X-ray absorbing strip. The energy of a photon hitting the absorber and the position of the absorption event along the strip is measured from the response in the two sensors by analyzing the relative signal sizes, pulse rise times, and the sum of the pulses measured at each sensor, We report on the recent PoST effort at Goddard for applications to large field of view, high-energy- resolution, X-ray astrophysics.

  3. Comparison of two position sensitive gamma-ray detectors based on continuous YAP and pixellated NaI(TI) for nuclear medical imaging applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jie; Ma, Hong-Guang; Ma, Wen-Yan; Zeng, Hui; Wang, Zhao-Min; Xu, Zi-Zhong

    2008-11-01

    Dedicated position sensitive gamma-ray detectors based on position sensitive photomultiplier tubes (PSPMTs) coupled to scintillation crystals, have been used for the construction of compact gamma-ray imaging systems, suitable for nuclear medical imaging applications such as small animal imaging and single organ imaging and scintimammography. In this work, the performance of two gamma-ray detectors: a continuous YAP scintillation crystal coupled to a Hamamastu R2486 PSPMT and a pixellated NaI(TI) scintillation array crystal coupled to the same PSPMT, is compared. The results show that the gamma-ray detector based on a pixellated NaI(TI) scintillation array crystal is a promising candidate for nuclear medical imaging applications, since their performance in terms of position linearity, spatial resolution and effective field of view (FOV) is superior than that of the gamma-ray detector based on a continuous YAP scintillation crystal. However, a better photodetector (Hamamatau H8500 Flat Panel PMT, for example) coupled to the continuous crystal is also likely a good selection for nuclear medicine imaging applications. Supported by National Nature Science Foundation of China (10275063)

  4. Continuous Positive Airway Pressure (CPAP)

    MedlinePlus

    ... these issues. What Are the Alternative Treatments For Sleep Apnea? Lifestyle change including weight loss and exercise can help to improve sleep apnea and its related health problems. Sleep positioning and ...

  5. Positive Behavior Support: Sustainability and Continuous Regeneration

    ERIC Educational Resources Information Center

    McIntosh, Kent; Turri, Mary G.

    2014-01-01

    Because of its widespread adoption and implementation (in over 13,000 schools in the US; Center on Positive Behavioral Interventions and Supports, 2010), there has been increasing attention to how School-wide Positive Behavior Support (SWPBS) systems can be sustained. Sustained implementation can be defined as "continued use of an…

  6. Increasing Sensitivity In Continuous-Flow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Sensitivity of continuous-flow electrophoresis (CFE) chamber increased by introducing lateral gradients in concentration of buffer solution and thickness of chamber. Such gradients, with resulting enhanced separation, achieved in CFE chamber with wedge-shaped cross section and collateral flow. Enables improved separations of homogeneous components of mixtures of variety of biologically important substances.

  7. Position Sensitive Detection System for Charged Particles

    SciTech Connect

    Coello, E. A.; Favela, F.; Curiel, Q.; Chavez, E; Huerta, A.; Varela, A.; Shapira, Dan

    2012-01-01

    The position sensitive detection system presented in this work employs the Anger logic algorithm to determine the position of the light spark produced by the passage of charged particles on a 170 x 170 x 10 mm3 scintillator material (PILOT-U). The detection system consists of a matrix of nine photomultipliers, covering a fraction of the back area of the scintillators. Tests made with a non-collimated alpha particle source together with a Monte Carlo simulation that reproduces the data, suggest an intrinsic position resolution of up to 6 mm is achieved.

  8. Large area position sensitive β-detector

    NASA Astrophysics Data System (ADS)

    Vaintraub, S.; Hass, M.; Edri, H.; Morali, N.; Segal, T.

    2015-03-01

    A new conceptual design of a large area electron detector, which is position and energy sensitive, was developed. This detector is designed for beta decay energies up to 4 MeV, but in principle can be re-designed for higher energies. The detector incorporates one large plastic scintillator and, in general, a limited number of photomultipliers (7 presently). The current setup was designed and constructed after an extensive Geant4 simulation study. By comparison of a single hit light distribution between the various photomultipliers to a pre-measured accurate position-response map, the anticipated position resolution is around 5 mm. The first benchmark experiments have been conducted in order to calibrate and confirm the position resolution of the detector. The new method, results of the first test experiments and comparison to simulations are presented.

  9. Position-Sensitive Scanning Fluorescence Correlation Spectroscopy

    PubMed Central

    Skinner, Joseph P.; Chen, Yan; Müller, Joachim D.

    2005-01-01

    Fluorescence correlation spectroscopy (FCS) uses a stationary laser beam to illuminate a small sample volume and analyze the temporal behavior of the fluorescence fluctuations within the stationary observation volume. In contrast, scanning FCS (SFCS) collects the fluorescence signal from a moving observation volume by scanning the laser beam. The fluctuations now contain both temporal and spatial information about the sample. To access the spatial information we synchronize scanning and data acquisition. Synchronization allows us to evaluate correlations for every position along the scanned trajectory. We use a circular scan trajectory in this study. Because the scan radius is constant, the phase angle is sufficient to characterize the position of the beam. We introduce position-sensitive SFCS (PSFCS), where correlations are calculated as a function of lag time and phase. We present the theory of PSFCS and derive expressions for diffusion, diffusion in the presence of flow, and for immobilization. To test PSFCS we compare experimental data with theory. We determine the direction and speed of a flowing dye solution and the position of an immobilized particle. To demonstrate the feasibility of the technique for applications in living cells we present data of enhanced green fluorescent protein measured in the nucleus of COS cells. PMID:15894645

  10. High speed curved position sensitive detector

    DOEpatents

    Hendricks, Robert W.; Wilson, Jack W.

    1989-01-01

    A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

  11. Continuous psychophysics: Target-tracking to measure visual sensitivity

    PubMed Central

    Bonnen, Kathryn; Burge, Johannes; Yates, Jacob; Pillow, Jonathan; Cormack, Lawrence K.

    2015-01-01

    We introduce a novel framework for estimating visual sensitivity using a continuous target-tracking task in concert with a dynamic internal model of human visual performance. Observers used a mouse cursor to track the center of a two-dimensional Gaussian luminance blob as it moved in a random walk in a field of dynamic additive Gaussian luminance noise. To estimate visual sensitivity, we fit a Kalman filter model to the human tracking data under the assumption that humans behave as Bayesian ideal observers. Such observers optimally combine prior information with noisy observations to produce an estimate of target position at each time step. We found that estimates of human sensory noise obtained from the Kalman filter fit were highly correlated with traditional psychophysical measures of human sensitivity (R2 > 97%). Because each frame of the tracking task is effectively a “minitrial,” this technique reduces the amount of time required to assess sensitivity compared with traditional psychophysics. Furthermore, because the task is fast, easy, and fun, it could be used to assess children, certain clinical patients, and other populations that may get impatient with traditional psychophysics. Importantly, the modeling framework provides estimates of decision variable variance that are directly comparable with those obtained from traditional psychophysics. Further, we show that easily computed summary statistics of the tracking data can also accurately predict relative sensitivity (i.e., traditional sensitivity to within a scale factor). PMID:25795437

  12. Continuous psychophysics: Target-tracking to measure visual sensitivity.

    PubMed

    Bonnen, Kathryn; Burge, Johannes; Yates, Jacob; Pillow, Jonathan; Cormack, Lawrence K

    2015-01-01

    We introduce a novel framework for estimating visual sensitivity using a continuous target-tracking task in concert with a dynamic internal model of human visual performance. Observers used a mouse cursor to track the center of a two-dimensional Gaussian luminance blob as it moved in a random walk in a field of dynamic additive Gaussian luminance noise. To estimate visual sensitivity, we fit a Kalman filter model to the human tracking data under the assumption that humans behave as Bayesian ideal observers. Such observers optimally combine prior information with noisy observations to produce an estimate of target position at each time step. We found that estimates of human sensory noise obtained from the Kalman filter fit were highly correlated with traditional psychophysical measures of human sensitivity (R2 > 97%). Because each frame of the tracking task is effectively a "minitrial," this technique reduces the amount of time required to assess sensitivity compared with traditional psychophysics. Furthermore, because the task is fast, easy, and fun, it could be used to assess children, certain clinical patients, and other populations that may get impatient with traditional psychophysics. Importantly, the modeling framework provides estimates of decision variable variance that are directly comparable with those obtained from traditional psychophysics. Further, we show that easily computed summary statistics of the tracking data can also accurately predict relative sensitivity (i.e., traditional sensitivity to within a scale factor). PMID:25795437

  13. Two-dimensional position sensitive radiation detectors

    DOEpatents

    Mihalczo, John T.

    1994-01-01

    Nuclear reaction detectors capable of position sensitivity with submillimeter resolution in two dimensions are each provided by placing arrays of scintillation or wave length shifting optical fibers formed of a plurality of such optical fibers in a side-by-side relationship in X and Y directions with a layer of nuclear reactive material operatively associated with surface regions of the optical fiber arrays. Each nuclear reaction occurring in the layer of nuclear reactive material produces energetic particles for simultaneously providing a light pulse in a single optical fiber in the X oriented array and in a single optical fiber in the Y oriented array. These pulses of light are transmitted to a signal producing circuit for providing signals indicative of the X-Y coordinates of each nuclear event.

  14. Two-dimensional position sensitive radiation detectors

    DOEpatents

    Mihalczo, J.T.

    1994-02-22

    Nuclear reaction detectors capable of position sensitivity with submillimeter resolution in two dimensions are each provided by placing arrays of scintillation or wavelength shifting optical fibers formed of a plurality of such optical fibers in a side-by-side relationship in X and Y directions with a layer of nuclear reactive material operatively associated with surface regions of the optical fiber arrays. Each nuclear reaction occurring in the layer of nuclear reactive material produces energetic particles for simultaneously providing a light pulse in a single optical fiber in the X oriented array and in a single optical fiber in the Y oriented array. These pulses of light are transmitted to a signal producing circuit for providing signals indicative of the X-Y coordinates of each nuclear event. 6 figures.

  15. The continuity of the output entropy of positive maps

    SciTech Connect

    Shirokov, Maxim E

    2011-10-31

    Global and local continuity conditions for the output von Neumann entropy for positive maps between Banach spaces of trace-class operators in separable Hilbert spaces are obtained. Special attention is paid to completely positive maps: infinite dimensional quantum channels and operations. It is shown that as a result of some specific properties of the von Neumann entropy (as a function on the set of density operators) several results on the output entropy of positive maps can be obtained, which cannot be derived from the general properties of entropy type functions. In particular, it is proved that global continuity of the output entropy of a positive map follows from its finiteness. A characterization of positive linear maps preserving continuity of the entropy (in the following sense: continuity of the entropy on an arbitrary subset of input operators implies continuity of the output entropy on this subset) is obtained. A connection between the local continuity properties of two completely positive complementary maps is considered. Bibliography: 21 titles.

  16. 32 CFR 154.13 - Sensitive positions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) Critical-sensitive. (A) Access to Top Secret information. (B) Development or approval of plans, policies... report required in subpart K. (e) Billet control system for Top Secret. (1) To standardize and control the issuance of Top Secret clearances within the Department of Defense, a specific designated...

  17. 32 CFR 154.13 - Sensitive positions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Critical-sensitive. (A) Access to Top Secret information. (B) Development or approval of plans, policies... report required in subpart K. (e) Billet control system for Top Secret. (1) To standardize and control the issuance of Top Secret clearances within the Department of Defense, a specific designated...

  18. 32 CFR 154.13 - Sensitive positions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Critical-sensitive. (A) Access to Top Secret information. (B) Development or approval of plans, policies... report required in subpart K. (e) Billet control system for Top Secret. (1) To standardize and control the issuance of Top Secret clearances within the Department of Defense, a specific designated...

  19. 32 CFR 154.13 - Sensitive positions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) Development or approval of war plans, plans or particulars of future major or special operations of war, or critical and extremely important items of war. (D) Investigative and certain investigative support duties...) Noncritical-sensitive. (A) Access to Secret or Confidential information. (B) Security police/provost...

  20. 32 CFR 154.13 - Sensitive positions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Development or approval of war plans, plans or particulars of future major or special operations of war, or critical and extremely important items of war. (D) Investigative and certain investigative support duties...) Noncritical-sensitive. (A) Access to Secret or Confidential information. (B) Security police/provost...

  1. SCALE Continuous-Energy Eigenvalue Sensitivity Coefficient Calculations

    DOE PAGESBeta

    Perfetti, Christopher M.; Rearden, Bradley T.; Martin, William R.

    2016-02-25

    Sensitivity coefficients describe the fractional change in a system response that is induced by changes to system parameters and nuclear data. The Tools for Sensitivity and UNcertainty Analysis Methodology Implementation (TSUNAMI) code within the SCALE code system makes use of eigenvalue sensitivity coefficients for an extensive number of criticality safety applications, including quantifying the data-induced uncertainty in the eigenvalue of critical systems, assessing the neutronic similarity between different critical systems, and guiding nuclear data adjustment studies. The need to model geometrically complex systems with improved fidelity and the desire to extend TSUNAMI analysis to advanced applications has motivated the developmentmore » of a methodology for calculating sensitivity coefficients in continuous-energy (CE) Monte Carlo applications. The Contributon-Linked eigenvalue sensitivity/Uncertainty estimation via Tracklength importance CHaracterization (CLUTCH) and Iterated Fission Probability (IFP) eigenvalue sensitivity methods were recently implemented in the CE-KENO framework of the SCALE code system to enable TSUNAMI-3D to perform eigenvalue sensitivity calculations using continuous-energy Monte Carlo methods. This work provides a detailed description of the theory behind the CLUTCH method and describes in detail its implementation. This work explores the improvements in eigenvalue sensitivity coefficient accuracy that can be gained through the use of continuous-energy sensitivity methods and also compares several sensitivity methods in terms of computational efficiency and memory requirements.« less

  2. Continuously-Variable Positive-Mesh Power Transmission

    NASA Technical Reports Server (NTRS)

    Johnson, J. L.

    1982-01-01

    Proposed transmission with continuously-variable speed ratio couples two mechanical trigonometric-function generators. Transmission is expected to handle higher loads than conventional variable-pulley drives; and, unlike variable pulley, positive traction through entire drive train with no reliance on friction to transmit power. Able to vary speed continuously through zero and into reverse. Possible applications in instrumentation where drive-train slippage cannot be tolerated.

  3. 43 CFR 422.11 - Position sensitivity and investigations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Position sensitivity and investigations. 422.11 Section 422.11 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... Requirements § 422.11 Position sensitivity and investigations. Each law enforcement contract or...

  4. 43 CFR 422.11 - Position sensitivity and investigations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Position sensitivity and investigations. 422.11 Section 422.11 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... Requirements § 422.11 Position sensitivity and investigations. Each law enforcement contract or...

  5. 43 CFR 422.11 - Position sensitivity and investigations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Position sensitivity and investigations. 422.11 Section 422.11 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... Requirements § 422.11 Position sensitivity and investigations. Each law enforcement contract or...

  6. 43 CFR 422.11 - Position sensitivity and investigations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Position sensitivity and investigations. 422.11 Section 422.11 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... Requirements § 422.11 Position sensitivity and investigations. Each law enforcement contract or...

  7. 43 CFR 422.11 - Position sensitivity and investigations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Position sensitivity and investigations. 422.11 Section 422.11 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... Requirements § 422.11 Position sensitivity and investigations. Each law enforcement contract or...

  8. Continuous positive airway pressure: Physiology and comparison of devices.

    PubMed

    Gupta, Samir; Donn, Steven M

    2016-06-01

    Nasal continuous positive airway pressure (CPAP) is increasingly used for respiratory support in preterm babies at birth and after extubation from mechanical ventilation. Various CPAP devices are available for use that can be broadly grouped into continuous flow and variable flow. There are potential physiologic differences between these CPAP systems and the choice of a CPAP device is too often guided by individual expertise and experience rather than by evidence. When interpreting the evidence clinicians should take into account the pressure generation sources, nasal interface, and the factors affecting the delivery of pressure, such as mouth position and respiratory drive. With increasing use of these devices, better monitoring techniques are required to assess the efficacy and early recognition of babies who are failing and in need of escalated support. PMID:26948884

  9. Duration of continuous positive airway pressure in premature infants.

    PubMed

    Bamat, Nicolas; Jensen, Erik A; Kirpalani, Haresh

    2016-06-01

    Continuous positive airway pressure (CPAP) has been used for respiratory support in premature infants for more than 40 years and is now a cornerstone of modern neonatal care. Clinical research on CPAP has primarily focused on understanding which devices and pressure sources best implement this therapy. In contrast, less research has examined the optimal duration over which CPAP is administered. We review this aspect of CPAP therapy. PMID:26948885

  10. Construction and commissioning of a position-sensitive ionization chamber

    NASA Astrophysics Data System (ADS)

    Kwag, M. S.; Chae, K. Y.; Cha, S. M.; Kim, A.; Kim, M. J.; Lee, E. J.; Lee, J. H.

    2016-05-01

    A position-sensitive ionization chamber has been constructed and commissioned at the Physics Department of Sungkyunkwan University to extract position information on incident charged particles for future nuclear reaction measurements. By utilizing the newly-designed position-sensitive anodes and the previously-commissioned portable gas-filled ionization chamber by Chae et al., position information on incident particles could be obtained. The device was tested with an 241Am α-emitting source, and the standard deviation of the fitted Gaussian distribution was measured to be 1.76 mm when a collimator with a 2 mm hole was used.

  11. Sensitivity limits of continuous wave cavity ring-down spectroscopy.

    PubMed

    Huang, Haifeng; Lehmann, Kevin K

    2013-12-19

    An optimized nonlinear least-squares fit algorithm for data processing in cavity ring-down spectroscopy (CRDS) is discussed, which improves the calculation efficiency substantially over using a general purpose fitting package. Theoretical absorption sensitivity limits for both the detector noise and the shot noise limited situations are derived and compared with experimental results. The effect of limiting the bandwidth of detection system on ring-down signal is discussed and compared with real ring-down data. The optimal trigger level and fitting interval are obtained for continuous wave cavity ring-down spectroscopy (cw-CRDS) in both the detector noise and shot noise limits, with the resulting sensitivity in units of cm(-1) per (Hz(1/2)) derived. Interestingly, it is found that the optimized shot noise limited sensitivity in cw-CRDS method is, in principle, comparable with the ultimate sensitivity of noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS). PMID:23978273

  12. [Continuously alternating prone and supine positioning in acute lung failure].

    PubMed

    Walz, M; Muhr, G

    1992-11-01

    Acute respiratory failure is still one the main problems in surgical intensive care. Unknown pathophysiological mechanisms permit only symptomatic therapy. Today ventilatory strategies by using PEEP und IRV are established to improve gas exchange and FRC by recruiting collapsed alveoli, decreasing intrapulmonary shunting and returning V/Q matching to normal. Furthermore different studies have shown the effects of supine and lateral decubitus posture in patients with acute respiratory failure. There are only rare reports on using the prone position, which doesn't require two-lung ventilation in difference to lateral position. We have studied 16 patients with acute respiratory failure by using continuous changing between prone and supine position under mechanical ventilation. All were male, aged 41.3 years in the middle and showed an average "Injury Severity Score" of 30 (13-50). 15 were trauma patients with blunt chest trauma in 11 cases. We have used prone position on threatening or manifest ARDS. In all patients we observed an increment of PaO2 during prone position on to 48 mmHg so that FiO2 could be reduced on an average of 0.2 within the first 48 h since changing patient's position. Posture changing depends on blood gas analysis, specifically on decreasing PaO2 after previous increment. Patients remained in prone and supine position at a mean of 6.3 (4.5-20) h and posture changing was proceeded over a period of 15.4 (7-32) days. No problems recording to blood pressure or mechanical ventilation appeared during prone position. 11 of 16 patients survived (68.8%), 5 died of cardiac (2) and multi organic failure (3) in connection with sepsis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1458988

  13. GPS and odometer data fusion for outdoor robots continuous positioning

    NASA Astrophysics Data System (ADS)

    Pozo-Ruz, Ana; Garcia-Perez, Lia; Garcia-Alegre, Maria C.; Guinea, Domingo; Ribeiro, Angela; Sandoval, Francisco

    2002-02-01

    Present work describes an approximation to obtain the best estimation of the position of the outdoor robot ROJO, a low cost lawnmower to perform unmanned precision agriculture task such are the spraying of pesticides in horticulture. For continuous location of ROJO, two redundant sensors have been installed onboard: a DGPS submetric precision model and an odometric system. DGPS system will allow an absolute positioning of the vehicle in the field, but GPS failures in the reception of the signals due to obstacles and electrical and meteorological disturbance, lead us to the integration of the odometric system. Thus, a robust odometer based upon magnetic strip sensors has been designed and integrated in the vehicle. These sensors continuosly deliver the position of the vehicle relative to its initial position, complementing the DGPS blindness periods. They give an approximated location of the vehicle in the field that can be in turn conveniently updated and corrected by the DGPS. Thus, to provided the best estimation, a fusion algorithm has been proposed and proved, wherein the best estimation is calculated as the maximum value of the join probability function obtained from both position estimation of the onboard sensors. Some results are presented to show the performance of the proposed sensor fusion technique.

  14. A position-sensitive alpha detector using a thin plastic scintillator combined with a position-sensitive photomultiplier tube

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Iida, Takao

    1998-12-01

    A position-sensitive alpha detector was developed and tested. The alpha detector consists of a thin plastic scintillator, a position-sensitive photomultiplier tube, a position calculation circuit and a personal computer based data acquisition system. Because the thin plastic scintillator has high-detection efficiency for alpha particles while it has low-sensitivity for beta particles or gamma ray, the detector can selectively detect alpha particles with low background counts. The spatial resolution of the detector was approximately 3 mm FWHM. An autoradiographic images of plutonium distribution in the lung of an animal as well as an image of an uranium particle were successively obtained. Spatial and energy distribution of radon daughters could also be measured. We conclude that the developed position-sensitive alpha detector is useful for some applications such as plutonium detection or alpha autoradiography as well as distribution analysis of radon daughters.

  15. Position sensitivity of MAMA detectors. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Morgan, J. S.; Slater, D. S.; Timothy, J. G.; Jenkins, E. B.

    1988-01-01

    The results of laboratory and telescopic measurements of the position sensitivity of a visible MAMA detector utilizing a 'coarse-fine' array are presented. The photometric accuracy of this detector was determined under point source illumination. It was found that computed centroid positions are accurate across the entire array to within 0.04 pixels.

  16. Self-Balancing Position-Sensitive Detector (SBPSD).

    PubMed

    Porrazzo, Ryan; Lydecker, Leigh; Gattu, Suhasini; Bakhru, Hassaram; Tokranova, Natalya; Castracane, James

    2015-01-01

    Optical position-sensitive detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS technology, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. An innovative type of optical position sensor was developed using two back-to-back connected photodiodes. These so called self-balancing position-sensitive detectors (SBPSDs) eliminate the need for external readout circuitry entirely. Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device. PSDs are commercially available only up to a length of 37 mm. Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that. PMID:26205266

  17. Self-Balancing Position-Sensitive Detector (SBPSD)

    PubMed Central

    Porrazzo, Ryan; Lydecker, Leigh; Gattu, Suhasini; Bakhru, Hassaram; Tokranova, Natalya; Castracane, James

    2015-01-01

    Optical position-sensitive detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS technology, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. An innovative type of optical position sensor was developed using two back-to-back connected photodiodes. These so called self-balancing position-sensitive detectors (SBPSDs) eliminate the need for external readout circuitry entirely. Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device. PSDs are commercially available only up to a length of 37 mm. Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that. PMID:26205266

  18. Dual Position Sensitive MWPC for tracking reaction products at VAMOS++

    NASA Astrophysics Data System (ADS)

    Vandebrouck, M.; Lemasson, A.; Rejmund, M.; Fremont, G.; Pancin, J.; Navin, A.; Michelagnoli, C.; Goupil, J.; Spitaels, C.; Jacquot, B.

    2016-03-01

    The characteristics and performance of a Dual Position Sensitive Multi-Wire Proportional Counter (DPS-MWPC) used to measure the scattering angle, the interaction position on the target and the velocity of reaction products detected in the VAMOS++ magnetic spectrometer, are reported. The detector consists of a pair of position sensitive low pressure MWPCs and provides both fast timing signals, along with the two-dimensional position coordinates required to define the trajectory of the reaction products. A time-of-flight resolution of 305(11) ps (FWHM) was measured. The measured resolutions (FWHM) were 2.5(3) mrad and 560(70) μm for the scattering angle and the interaction point at the target respectively. The subsequent improvement of the Doppler correction of the energy of the γ-rays, detected in the γ-ray tracking array AGATA in coincidence with isotopically identified ions in VAMOS++, is also discussed.

  19. Development of a novel position-sensitive microchannel plate detector

    NASA Astrophysics Data System (ADS)

    Wiggins, Blake; Siwal, Davinder; Desouza, Romualdo

    2015-10-01

    Position sensitive microchannel plate (MCP) detectors which measure the position of an incident electron, ion, or photon, are useful in imaging applications. Recently, a novel detector, which utilizes an induced approach to provide position sensitivity, has been developed. In the prototype detector, using only the zero-crossing point of the inherently bipolar signals, a position resolution of 466 μm (FWHM) has been achieved. Implementing a differential readout may improve on this resolution. To realize this differential approach, a better understanding of the dependence of the induced signal shape on the position of the electron cloud is required. To characterize the dependence of the induced signal shape on position a resistive anode (RA) has been incorporated into the detector. The RA will allow determination of the centroid of the electron cloud. Factors impacting the position resolution obtained with the RA will be discussed and the achieved position resolution of 157 μm (FWHM) will be presented. Supported by the US DOE NNSA under Award No. DE-NA0002012.

  20. Continuing Education Workshops in Bioinformatics Positively Impact Research and Careers

    PubMed Central

    Brazas, Michelle D.; Ouellette, B. F. Francis

    2016-01-01

    Bioinformatics.ca has been hosting continuing education programs in introductory and advanced bioinformatics topics in Canada since 1999 and has trained more than 2,000 participants to date. These workshops have been adapted over the years to keep pace with advances in both science and technology as well as the changing landscape in available learning modalities and the bioinformatics training needs of our audience. Post-workshop surveys have been a mandatory component of each workshop and are used to ensure appropriate adjustments are made to workshops to maximize learning. However, neither bioinformatics.ca nor others offering similar training programs have explored the long-term impact of bioinformatics continuing education training. Bioinformatics.ca recently initiated a look back on the impact its workshops have had on the career trajectories, research outcomes, publications, and collaborations of its participants. Using an anonymous online survey, bioinformatics.ca analyzed responses from those surveyed and discovered its workshops have had a positive impact on collaborations, research, publications, and career progression. PMID:27281025

  1. Continuing Education Workshops in Bioinformatics Positively Impact Research and Careers.

    PubMed

    Brazas, Michelle D; Ouellette, B F Francis

    2016-06-01

    Bioinformatics.ca has been hosting continuing education programs in introductory and advanced bioinformatics topics in Canada since 1999 and has trained more than 2,000 participants to date. These workshops have been adapted over the years to keep pace with advances in both science and technology as well as the changing landscape in available learning modalities and the bioinformatics training needs of our audience. Post-workshop surveys have been a mandatory component of each workshop and are used to ensure appropriate adjustments are made to workshops to maximize learning. However, neither bioinformatics.ca nor others offering similar training programs have explored the long-term impact of bioinformatics continuing education training. Bioinformatics.ca recently initiated a look back on the impact its workshops have had on the career trajectories, research outcomes, publications, and collaborations of its participants. Using an anonymous online survey, bioinformatics.ca analyzed responses from those surveyed and discovered its workshops have had a positive impact on collaborations, research, publications, and career progression. PMID:27281025

  2. Control system design for a Continuous Positive Airway Pressure ventilator.

    PubMed

    Chen, Zheng-Long; Hu, Zhao-Yan; Dai, Hou-De

    2012-01-01

    Continuous Positive Airway Pressure (CPAP) ventilation remains a mainstay treatment for obstructive sleep apnea syndrome (OSAS). Good pressure stability and pressure reduction during exhalation are of major importance to ensure clinical efficacy and comfort of CPAP therapy. In this study an experimental CPAP ventilator was constructed using an application-specific CPAP blower/motor assembly and a microprocessor. To minimize pressure variations caused by spontaneous breathing as well as the uncomfortable feeling of exhaling against positive pressure, we developed a composite control approach including the feed forward compensator and feedback proportional-integral-derivative (PID) compensator to regulate the pressure delivered to OSAS patients. The Ziegler and Nichols method was used to tune PID controller parameters. And then we used a gas flow analyzer (VT PLUS HF) to test pressure curves, flow curves and pressure-volume loops for the proposed CPAP ventilator. The results showed that it met technical criteria for sleep apnea breathing therapy equipment. Finally, the study made a quantitative comparison of pressure stability between the experimental CPAP ventilator and commercially available CPAP devices. PMID:22296604

  3. Control system design for a continuous positive airway pressure ventilator

    PubMed Central

    2012-01-01

    Continuous Positive Airway Pressure (CPAP) ventilation remains a mainstay treatment for obstructive sleep apnea syndrome (OSAS). Good pressure stability and pressure reduction during exhalation are of major importance to ensure clinical efficacy and comfort of CPAP therapy. In this study an experimental CPAP ventilator was constructed using an application-specific CPAP blower/motor assembly and a microprocessor. To minimize pressure variations caused by spontaneous breathing as well as the uncomfortable feeling of exhaling against positive pressure, we developed a composite control approach including the feed forward compensator and feedback proportional-integral-derivative (PID) compensator to regulate the pressure delivered to OSAS patients. The Ziegler and Nichols method was used to tune PID controller parameters. And then we used a gas flow analyzer (VT PLUS HF) to test pressure curves, flow curves and pressure-volume loops for the proposed CPAP ventilator. The results showed that it met technical criteria for sleep apnea breathing therapy equipment. Finally, the study made a quantitative comparison of pressure stability between the experimental CPAP ventilator and commercially available CPAP devices. PMID:22296604

  4. Position sensitive radioactivity detection for gas and liquid chromatography

    DOEpatents

    Cochran, Joseph L.; McCarthy, John F.; Palumbo, Anthony V.; Phelps, Tommy J.

    2001-01-01

    A method and apparatus are provided for the position sensitive detection of radioactivity in a fluid stream, particularly in the effluent fluid stream from a gas or liquid chromatographic instrument. The invention represents a significant advance in efficiency and cost reduction compared with current efforts.

  5. Use of nasal continuous positive airway pressure during neonatal transfers

    PubMed Central

    Bomont, R K; Cheema, I U

    2006-01-01

    Objective To review all cases in which nasal continuous positive airway pressure (CPAP) was used as a means of respiratory support during land based ambulance transfers by a regional neonatal transport service. Design Retrospective study based on review of transport records. Results A total of 1175 transfer requests were received over the 21 month period. The infant in 163 of these cases was receiving nasal CPAP. Ninety two referrals were accepted by the doctor/nurse practitioner led team. Of these, 84 were transported while receiving nasal CPAP. Intervention during transport was required in three of these cases. Fifty five referrals were accepted by the nurse led team. Of these, 16 were transported while receiving nasal CPAP. Intervention was required in two cases. Conclusion There is a small but significant demand for transferring infants who are receiving nasal CPAP. Nasal CPAP appears to be a safe method of respiratory support for a carefully selected group of infants during land based ambulance transfers. PMID:16204357

  6. Strategies for the prevention of continuous positive airway pressure failure.

    PubMed

    Sahni, Rakesh; Schiaratura, Maria; Polin, Richard A

    2016-06-01

    Progress in neonatal intensive care is closely linked to improvements in the management of respiratory failure in preterm infants. Current modalities of respiratory support range from the more benign continuous positive airway pressure (CPAP) to various modes of mechanical ventilation. Data from recent randomized control trials suggest that the use of nasal (n)CPAP as the initial mode of respiratory support in critically ill very low birth weight infants is associated with a lower incidence of chronic lung disease. The practice of early initiation of nasal-prong CPAP in all spontaneously breathing infants at Columbia University has resulted in very low rates of chronic lung disease for decades. Many institutions have attempted to replicate the practices and results at Columbia University. However, success rates with nCPAP are highly variable, which may in part be attributable to how well it is utilized. With recent renewed interest in non-invasive respiratory support, particularly bubble nCPAP, it is essential to evaluate strategies for the prevention of CPAP failure. This review discusses strategies that address these issues and shares the practical aspects for replicating success with bubble nCPAP. In addition, it reviews desirable features, major components, and physiological consequences of various bubble CPAP systems along with clinical experience of CPAP use. PMID:26936186

  7. Interdigited dual-cell position-sensitive device

    NASA Astrophysics Data System (ADS)

    Shie, Jin-Shown

    1992-10-01

    A special one-dimensional position-sensitive device for detection of a light-spot location is designed and fabricated. The device is composed of a pair of photodiodes with complementarily interdigited comb configuration. The width of comb teeth is characterized by a designated distributive function, hence, the coordination information of a light spot falling upon the device can be determined by photo-induced currents of the two diodes. This device is useful as the position sensing element in camera-autofocus application.

  8. A position sensitive microchannel photomultiplier for ultraviolet space astronomy

    NASA Technical Reports Server (NTRS)

    Lampton, M.; Siegmund, O. H. W.; Bixler, J.; Bowyer, S.

    1986-01-01

    The 25-mm microchannel-plate, position-sensitive UV astronomy photomultiplier tube presented is intended for the EOM-1 Spacelab Mission's FAUST payload and conducts wide-field imaging surveys in the VUV over the 1400-1800-A range. The sealed detector encompasses a CsI photocathode deposited on the inner surface of a MgF2 window, a stack of microchannel plates, and a wedge-and-strip two-dimensional position-sensing anode. Since the wedge-and-strip principle requires only three anode signals, flight electronics can be reduced to three charge amplifiers and three analog-to-digital converters.

  9. Development of a fast position-sensitive laser beam detector

    SciTech Connect

    Chavez, Isaac; Huang Rongxin; Henderson, Kevin; Florin, Ernst-Ludwig; Raizen, Mark G.

    2008-10-15

    We report the development of a fast position-sensitive laser beam detector. The detector uses a fiber-optic bundle that spatially splits the incident beam, followed by a fast balanced photodetector. The detector is applied to the study of Brownian motion of particles on fast time scales with 1 A spatial resolution. Future applications include the study of molecule motors, protein folding, as well as cellular processes.

  10. Integrated cooling channels in position-sensitive silicon detectors

    NASA Astrophysics Data System (ADS)

    Andricek, L.; Boronat, M.; Fuster, J.; Garcia, I.; Gomis, P.; Marinas, C.; Ninkovic, J.; Perelló, M.; Villarejo, M. A.; Vos, M.

    2016-06-01

    We present an approach to construct position-sensitive silicon detectors with an integrated cooling circuit. Tests on samples demonstrate that a very modest liquid flow very effectively cool the devices up to a power dissipation of over 10 W/cm2. The liquid flow is found to have a negligible impact on the mechanical stability. A finite-element simulation predicts the cooling performance to an accuracy of approximately 10%.

  11. Spectroscopy of Actinide Nuclei - Perspectives with Position Sensitive HPGe Detectors

    NASA Astrophysics Data System (ADS)

    Reiter, P.; Birkenbach, B.; Kotthaus, T.

    Recent advances in in-beam gamma-ray spectroscopy of actinide nuclei are based on highly efficient arrays of escape-suppressed spectrometers. The sensitivity of these detector arrays is greatly enhanced by the combination with powerful mass separators or particle detector systems. This technique is demonstrated by an experiment to investigate excited states in 234U after the one-neutron-transfer reaction 235U(d,t). In coincidence with the outgoing tritons, γ-rays were detected with the highly efficient MINIBALL spectrometer. In the near future an even enhanced sensitivity will be achieved by utilizing position sensitive HPGe detectors which will exploit the novel detection method of gamma-ray energy tracking in electrically segmented germanium detectors. An example for this novel approach is the investigation neutron-rich actinide Th and U nuclei after multi nucleon transfer reactions employing the AGATA demonstrator and PRISMA setup at LNL, Italy. A primary 136Xe beam hitting a 238U target was used to produce the nuclei of interest. Beam-like reaction products after neutron transfer were selected by the PRISMA spectrometer. Coincident γ-rays from excited states in beam and target like particles were measured with the position sensitive AGATA HPGe detectors. Improved Doppler correction and quality of the γ-spectra is based on the novel γ-ray tracking technique, which was successfully exploited in this region.

  12. Two-dimensional position sensitive ionization chamber with GEM

    NASA Astrophysics Data System (ADS)

    Kitamura, Noritaka; Noro, Tetsuo; Sakaguchi, Satoshi; Takao, Hideaki; Nishio, Yasutaka

    2014-09-01

    We have been developing a multi-anode ionization chamber for Accelerator Mass Spectrometry (AMS) at Kyushu University. Furthermore, we are planning to construct a neutron detector with high position resolution by combining the chamber with Gas Electron Multiplier (GEM) and a neutron converter. One of purposes is the measurement of p-> , pn knockout reaction from unstable nuclei. The multi-anode ionization chamber is composed of subdivided multiple anodes, a cathode to produce an uniform electric field, and a Frisch grid. The chamber must have position sensitivity because obtaining a beam profile is required for AMS measurements, where counting loss should be avoided. Also in the case of the neutron detector, it is necessary to measure the position to deduce the scattering angles. We have recently established a two-dimensional position readout system by the following methods: the measurement of horizontal position is enabled by trimming some anodes into wedge-like shape, and vertical position can be determined by the ratio of induced charge on the grid to the total charge on anodes. In addition, improvement of S/N ratio is important for isotope separation and position resolution. We installed a rectangular-shaped GEM and tried improving S/N ratio by electron amplification.

  13. Continuity for Young Children: Positive Transitions to Elementary School.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    Recognizing that children who experience continuity as they enter formal education are more likely to sustain their earlier gains than children who do not experience continuity, this document provides guidelines for preschool, Head Start, and elementary teachers and administrators on transition procedures. An executive summary begins the document.…

  14. Michrochannel plate for position sensitive alpha particle detection

    SciTech Connect

    Paul Hurley and James Tinsley

    2007-08-31

    This paper will describe the use of a microchannel plate (MCP) as the associated particle detector on a sealed tube neutron generator. The generator produces neutrons and associated alpha particles for use as a probe to locate and identify hidden explosives in associated particle imaging (API). The MCP measures the position in two dimensions and precise timing of the incident alpha particle, information which is then used to calculate the emission time and direction of the corresponding neutron. The MCP replaces the position-sensitive photomultipler tube (PSPMT) which, until recently, had been the only detector available for measuring position and timing for alpha particles in neutron generator applications. Where the PSPMT uses charge division for generating position information, a process that requires a first order correction to each pulse, the MCP uses delay-line timing, which requires no correction. The result is a device with an order of magnitude improvement in both position resolution and timing compared to the PSPMT. Hardware and software development and the measurements made to characterize the MCP for API applications are described.

  15. Canadian Penning Trap Mass Measurements using a Position Sensitive MCP

    NASA Astrophysics Data System (ADS)

    Kuta, Trenton; Aprahamian, Ani; Marley, Scott; Nystrom, Andrew; Clark, Jason; Perez Galvan, Adrian; Hirsh, Tsviki; Savard, Guy; Orford, Rodney; Morgan, Graeme

    2015-10-01

    The primary focus of the Canadian Penning Trap (CPT) located at Argonne National Lab is to determine the masses of various isotopes produced in the spontaneous fission of Californium. Currently, the CPT is operating in conjunction with CARIBU at the ATLAS facility in an attempt to measure neutron-rich nuclei produced by a 1.5 Curie source of Californium 252. The masses of nuclei produced in fission is accomplished by measuring the cyclotron frequency of the isotopes circling within the trap. This frequency is determined by a position sensitive MCP, which records the relative position of the isotope in the trap at different times. Using these position changes over time in connection with a center spot, angles between these positions are calculated and used to determine the frequency. Most of the work currently being conducted on the CPT is focused on the precision of these frequency measurements. The use of traps has revolutionized the measurements of nuclear masses to very high precision. The optimization methods employed here include focusing the beam in order to reduce the spread on the position of the isotope as well as the tuning of the MR-ToF, a mass separator that is intended on removing contaminants in the beam. This work was supported by the nuclear Grant PHY-1419765 for the University of Notre Dame.

  16. Implementation of Complex Signal Processing Algorithms for Position-Sensitive Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Smith, Stephen J.

    2008-01-01

    We have recently reported on a theoretical digital signal-processing algorithm for improved energy and position resolution in position-sensitive, transition-edge sensor (POST) X-ray detectors [Smith et al., Nucl, lnstr and Meth. A 556 (2006) 2371. PoST's consists of one or more transition-edge sensors (TES's) on a large continuous or pixellated X-ray absorber and are under development as an alternative to arrays of single pixel TES's. PoST's provide a means to increase the field-of-view for the fewest number of read-out channels. In this contribution we extend the theoretical correlated energy position optimal filter (CEPOF) algorithm (originally developed for 2-TES continuous absorber PoST's) to investigate the practical implementation on multi-pixel single TES PoST's or Hydras. We use numerically simulated data for a nine absorber device, which includes realistic detector noise, to demonstrate an iterative scheme that enables convergence on the correct photon absorption position and energy without any a priori assumptions. The position sensitivity of the CEPOF implemented on simulated data agrees very well with the theoretically predicted resolution. We discuss practical issues such as the impact of random arrival phase of the measured data on the performance of the CEPOF. The CEPOF algorithm demonstrates that full-width-at- half-maximum energy resolution of < 8 eV coupled with position-sensitivity down to a few 100 eV should be achievable for a fully optimized device.

  17. Position-Sensitive Nuclear Spectroscopy with Pixel Detectors

    SciTech Connect

    Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav

    2007-10-26

    State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

  18. Position-sensitive photodetector for rotation-angle transducers

    NASA Astrophysics Data System (ADS)

    Gurin, N. T.; Novikov, S. G.; Korneev, I. V.; Shtan'ko, A. A.; Rodionov, V. A.

    2011-03-01

    A new position-sensitive photodetector (PSPD) for photoelectric transducers of rotation angle is described, which is based on a three-layer ring sector structure. The output voltage of the PSPD is a linear function of the angle of rotation of a light-emitting diode relative to the PSPD contacts. The proposed device is highly reliable and ensures angle determination to within 7 min of arc. Rotation-angle transducers based on this PSPD are compatible with any measuring, matching, and processing equipment.

  19. Emulation workbench for position sensitive gaseous scintillation detectors

    NASA Astrophysics Data System (ADS)

    Pereira, L.; Margato, L. M. S.; Morozov, A.; Solovov, V.; Fraga, F. A. F.

    2015-12-01

    Position sensitive detectors based on gaseous scintillation proportional counters with Anger-type readout are being used in several research areas such as neutron detection, search for dark matter and neutrinoless double beta decay. Design and optimization of such detectors are complex and time consuming tasks. Simulations, while being a powerful tool, strongly depend on the light transfer models and demand accurate knowledge of many parameters, which are often not available. Here we describe an alternative approach based on the experimental evaluation of a detector using an isotropic point-like light source with precisely controllable light emission properties, installed on a 3D positioning system. The results obtained with the developed setup at validation conditions, when the scattered light is strongly suppressed show good agreement with simulations.

  20. A three dimensionally position sensitive large area detector

    NASA Astrophysics Data System (ADS)

    Pochodzalla, J.; Butsch, R.; Heck, B.; Hlawatsch, G.; Miczaika, A.; Rabe, H. J.; Rosner, G.

    1985-01-01

    A large area detector consisting of a parallel plate avalanche counter (PPAC) and a trapezohedral ionization chamber (TIC) is described. Its active area is 184 cm 2. The time resolution of the PPAC is 175 ps. The energy resolution of the TIC is 0.4%, the energy loss resolution 2.8%, the nuclear charge resolution 2.3%. The TIC is position sensitive in three dimensions. The position x is measured via a saw-tooth anode with a resolution of 0.7 mm; the drift time coordinate shows a resolution of δy ≅ mm. The range z is determined by a new technique, a graded density Frisch grid. It enlarges the dynamic range of the charge measurement down to the Bragg maximum at E/ A ˜ 1 MeV. The resolution is δZ/ Z ≅ 3.5%

  1. Positioning a University Outreach Center: Strategies for Support and Continuation.

    ERIC Educational Resources Information Center

    Skivington, Kristen D.

    1998-01-01

    Argues that a strong case can be made for supporting outreach as a value-added function in a university. Specific strategies for positioning outreach within the university by developing a power base are outlined. The case of the University of Michigan-Flint is offered as an example of this approach. Seven lessons learned in the process are noted.…

  2. Continuity and discontinuity in maternal sensitivity at 6, 24, and 42 months in a high-risk sample.

    PubMed

    Pianta, R C; Sroufe, L A; Egeland, B

    1989-04-01

    Continuity and discontinuity in maternal sensitivity from 6 and 24 months to 42 months were examined in a sample of 135 disadvantaged mothers and their firstborn children. Sensitivity at 6 and 24 months accounted for 18% of the variance in 42-month maternal sensitivity for boys, 14% for girls. Discontinuity was examined using residual scores. Less maternal sensitivity than predicted was related to stressful environmental and child characteristics for both boys and girls, while greater sensitivity than predicted was related to mothers' experiences of emotional support, girls' positive individual characteristics, and boys who were seen as unengaged. PMID:2924663

  3. Delay-Line Three-Dimensional Position Sensitive Radiation Detection

    NASA Astrophysics Data System (ADS)

    Jeong, Manhee

    High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR

  4. Positron camera using position-sensitive detectors: PENN-PET

    SciTech Connect

    Muehllehner, G.; Karp, J.S.

    1986-01-01

    A single-slice positron camera has been developed with good spatial resolution and high count rate capability. The camera uses a hexagonal arrangement of six position-sensitive NaI(Tl) detectors. The count rate capability of NaI(Tl) was extended to 800k cps through the use of pulse shortening. In order to keep the detectors stationary, an iterative reconstruction algorithm was modified which ignores the missing data in the gaps between the six detectors and gives artifact-free images. The spatial resolution, as determined from the image of point sources in air, is 6.5 mm full width at half maximum. We have also imaged a brain phantom and dog hearts.

  5. Position Sensitive Detectors Mounted with Scintillators and Silicon Photomultipliers

    NASA Astrophysics Data System (ADS)

    Carvalhaes, Roberto P. M.; Bonifácio, Daniel A. B.; Moralles, Maurício

    2011-08-01

    This work presents the first results obtained in the "Assembly and characterization of position sensitive detectors composed of scintillators coupled to silicon photomultipliers" project. The development of new x and γ radiation detectors have found several technological applications, especially in medical physics, where γ detectors that can be used in high intensity magnetic field are of particular importance. The experimental setup consisted of coupling of two silicon photomultipliers (SiPM) to the small sides of a 3×3×100 mm3 scintillator and the coupling of one SiPM to one of the small sides of a 3×3×10 mm3 scintillator. We found that the detectors used in this study presented an energy resolution that is in agreement with those observed in scintillators of the same family coupled to conventional photomultipliers. Besides that, there is a strong correlation between the difference of the light intensity in both SiPMs of the long detector and the position of the γ source. The results confirm the great potential of application of such detectors.

  6. Beam tests of a 3-D position sensitive scintillation detector

    SciTech Connect

    Labanti, C.; Hall, C.J.; Agrinier, B.; Byard, K.; Dean, A.J.; Goldwurm, A.; Harding, J.S.

    1989-02-01

    An array of 30 position sensitive scintillator bars has been tested in a gamma-ray beam from I.N.S.T.N. Van de Graff facility at the Centre d'Etudes Nucleaires, Saclay, France. The gamma-ray energies ranged from 6 MeV to 17 MeV. The bars are similar to those proposed for use in the GRASP gamma-ray telescope satellite imaging plane. They are manufactured from CsI(T1) covered with a highly reflective diffusive wrapping, and are read out using large area PIN photodiodes. Each bar measures 15.0 cm by 1.3 cm by 1.3 cm. The beam test unit was comprised of 30 bars stacked in a 5 by 6 array. The photodiodes were optically coupled to the end face of each bar and were connected to a processing chain comprised of a low noise preamplifier, a high gain shaping amplifier, and a digitisation and data collection system. Several experiments were performed with the unit to assess the spectral response, position resolution, and background rejection capabilities of the complete detector. The test procedure is explained and some results are presented.

  7. ASIC for High Rate 3D Position Sensitive Detectors

    SciTech Connect

    Vernon, E.; De Geronimo, G.; Ackley, K.; Fried, J.; He, Z.; Herman, C.; Zhang, F.

    2010-06-16

    We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 {micro}s, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.

  8. Continuous-energy eigenvalue sensitivity coefficient calculations in TSUNAMI-3D

    SciTech Connect

    Perfetti, C. M.; Rearden, B. T.

    2013-07-01

    Two methods for calculating eigenvalue sensitivity coefficients in continuous-energy Monte Carlo applications were implemented in the KENO code within the SCALE code package. The methods were used to calculate sensitivity coefficients for several test problems and produced sensitivity coefficients that agreed well with both reference sensitivities and multigroup TSUNAMI-3D sensitivity coefficients. The newly developed CLUTCH method was observed to produce sensitivity coefficients with high figures of merit and a low memory footprint, and both continuous-energy sensitivity methods met or exceeded the accuracy of the multigroup TSUNAMI-3D calculations. (authors)

  9. Development of a SCALE Tool for Continuous-Energy Eigenvalue Sensitivity Coefficient Calculations

    SciTech Connect

    Perfetti, Christopher M; Rearden, Bradley T

    2013-01-01

    Two methods for calculating eigenvalue sensitivity coefficients in continuous-energy Monte Carlo applications were implemented in the KENO code within the SCALE code package. The methods were used to calculate sensitivity coefficients for several criticality safety problems and produced sensitivity coefficients that agreed well with both reference sensitivities and multigroup TSUNAMI-3D sensitivity coefficients. The newly developed CLUTCH method was observed to produce sensitivity coefficients with high figures of merit and low memory requirements, and both continuous-energy sensitivity methods met or exceeded the accuracy of the multigroup TSUNAMI-3D calculations.

  10. Development of a SCALE Tool for Continuous-Energy Eigenvalue Sensitivity Coefficient Calculations

    NASA Astrophysics Data System (ADS)

    Perfetti, Christopher M.; Rearden, Bradley T.

    2014-06-01

    Two methods for calculating eigenvalue sensitivity coefficients in continuous-energy Monte Carlo applications were implemented in the KENO code within the SCALE code package. The methods were used to calculate sensitivity coefficients for several criticality safety problems and produced sensitivity coefficients that agreed well with both reference sensitivities and multigroup TSUNAMI-3D sensitivity coefficients. The newly developed CLUTCH method was observed to produce sensitivity coefficients with high figures of merit and low memory requirements, and both continuous-energy sensitivity methods met or exceeded the accuracy of the multigroup TSUNAMI-3D calculations.

  11. READOUT ASIC FOR 3D POSITION-SENSITIVE DETECTORS.

    SciTech Connect

    DE GERONIMO,G.; VERNON, E.; ACKLEY, K.; DRAGONE, A.; FRIED, J.; OCONNOR, P.; HE, Z.; HERMAN, C.; ZHANG, F.

    2007-10-27

    We describe an application specific integrated circuit (ASIC) for 3D position-sensitive detectors. It was optimized for pixelated CZT sensors, and it measures, corresponding to an ionizing event, the energy and timing of signals from 121 anodes and one cathode. Each channel provides low-noise charge amplification, high-order shaping, along with peak- and timing-detection. The cathode's timing can be measured in three different ways: the first is based on multiple thresholds on the charge amplifier's voltage output; the second uses the threshold crossing of a fast-shaped signal; and the third measures the peak amplitude and timing from a bipolar shaper. With its power of 2 mW per channel the ASIC measures, on a CZT sensor Connected and biased, charges up to 100 fC with an electronic resolution better than 200 e{sup -} rms. Our preliminary spectral measurements applying a simple cathode/mode ratio correction demonstrated a single-pixel resolution of 4.8 keV (0.72 %) at 662 keV, with the electronics and leakage current contributing in total with 2.1 keV.

  12. Position sensitivity in 3"×3" Spectroscopic LaBr3:Ce Crystals

    NASA Astrophysics Data System (ADS)

    Blasi, N.; Giaz, A.; Boiano, C.; Brambilla, S.; Camera, F.; Million, B.; Riboldi, S.

    2015-06-01

    The position sensitivity of a thick, cylindrical and continuous 3" × 3" (7.62 cm × 7.62 cm) LaBr3:Ce crystal with diffusive surfaces was investigated. Nuclear physics basic research uses thick LaBr3:Ce crystals (> 3cm) to measure medium or high energy gamma rays (0.5 MeV < Eγ< 20 MeV). In the first measurement the PMT photocathode entrance window was covered by black absorber except for a small window 1 cm × 1cm wide. A complete scan of the detector over a 0.5 cm step grid was performed. The data show that even in a 3" thick LaBr3:Ce crystal with diffusive surfaces the position of the full energy peak centroid depends on the source position. The position of the full energy peak centroids are sufficient to identify the collimated gamma source position. The crystal was then coupled to four Position Sensitive Photomultipliers (PSPMT). We acquired the signals from the 256 segments of the four PSPMTs grouping them into 16 elements. An event by event analysis shows a positon resolution of the order of 2 cm.

  13. 78 FR 42982 - Submission for Review: Information Collection; Questionnaire for Non-Sensitive Positions (SF 85)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-18

    ... MANAGEMENT Submission for Review: Information Collection; Questionnaire for Non-Sensitive Positions (SF 85...), Office of Management and Budget (OMB) Control No. 3206-NEW, for Questionnaire for Non-Sensitive Positions...@opm.gov . SUPPLEMENTARY INFORMATION: The Questionnaire for Non-Sensitive Positions, SF 85, housed in...

  14. Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements

    NASA Astrophysics Data System (ADS)

    Ferrari, Giorgio; Sampietro, Marco

    2007-09-01

    This article presents a wide bandwidth transimpedance amplifier based on the series of an integrator and a differentiator stage, having an additional feedback loop to discharge the standing current from the device under test (DUT) to ensure an unlimited measuring time opportunity when compared to switched discharge configurations while maintaining a large signal amplification over the full bandwidth. The amplifier shows a flat response from 0.6Hzto1.4MHz, the capability to operate with leakage currents from the DUT as high as tens of nanoamperes, and rail-to-rail dynamic range for sinusoidal current signals independent of the DUT leakage current. Also available is a monitor output of the stationary current to track experimental slow drifts. The circuit is ideal for noise spectral and impedance measurements of nanodevices and biomolecules when in the presence of a physiological medium and in all cases where high sensitivity current measurements are requested such as in scanning probe microscopy systems.

  15. High-sensitivity, high-speed continuous imaging system

    DOEpatents

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

    A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

  16. Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements.

    PubMed

    Ferrari, Giorgio; Sampietro, Marco

    2007-09-01

    This article presents a wide bandwidth transimpedance amplifier based on the series of an integrator and a differentiator stage, having an additional feedback loop to discharge the standing current from the device under test (DUT) to ensure an unlimited measuring time opportunity when compared to switched discharge configurations while maintaining a large signal amplification over the full bandwidth. The amplifier shows a flat response from 0.6 Hz to 1.4 MHz, the capability to operate with leakage currents from the DUT as high as tens of nanoamperes, and rail-to-rail dynamic range for sinusoidal current signals independent of the DUT leakage current. Also available is a monitor output of the stationary current to track experimental slow drifts. The circuit is ideal for noise spectral and impedance measurements of nanodevices and biomolecules when in the presence of a physiological medium and in all cases where high sensitivity current measurements are requested such as in scanning probe microscopy systems. PMID:17902966

  17. Development of Continuous-Energy Eigenvalue Sensitivity Coefficient Calculation Methods in the Shift Monte Carlo Code

    SciTech Connect

    Perfetti, Christopher M; Martin, William R; Rearden, Bradley T; Williams, Mark L

    2012-01-01

    Three methods for calculating continuous-energy eigenvalue sensitivity coefficients were developed and implemented into the SHIFT Monte Carlo code within the Scale code package. The methods were used for several simple test problems and were evaluated in terms of speed, accuracy, efficiency, and memory requirements. A promising new method for calculating eigenvalue sensitivity coefficients, known as the CLUTCH method, was developed and produced accurate sensitivity coefficients with figures of merit that were several orders of magnitude larger than those from existing methods.

  18. Three-dimensional, position-sensitive radiation detection

    DOEpatents

    He, Zhong; Zhang, Feng

    2010-04-06

    Disclosed herein is a method of determining a characteristic of radiation detected by a radiation detector via a multiple-pixel event having a plurality of radiation interactions. The method includes determining a cathode-to-anode signal ratio for a selected interaction of the plurality of radiation interactions based on electron drift time data for the selected interaction, and determining the radiation characteristic for the multiple-pixel event based on both the cathode-to-anode signal ratio and the electron drift time data. In some embodiments, the method further includes determining a correction factor for the radiation characteristic based on an interaction depth of the plurality of radiation interactions, a lateral distance between the selected interaction and a further interaction of the plurality of radiation interactions, and the lateral positioning of the plurality of radiation interactions.

  19. Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

    SciTech Connect

    Not Available

    1999-06-01

    The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

  20. CONTINUOUS-ENERGY MONTE CARLO METHODS FOR CALCULATING GENERALIZED RESPONSE SENSITIVITIES USING TSUNAMI-3D

    SciTech Connect

    Perfetti, Christopher M; Rearden, Bradley T

    2014-01-01

    This work introduces a new approach for calculating sensitivity coefficients for generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The approach presented in this paper, known as the GEAR-MC method, allows for the calculation of generalized sensitivity coefficients for multiple responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here, and proof of principle is demonstrated by using the GEAR-MC method to calculate sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications.

  1. Performance of a position-sensitive scintillation detector.

    PubMed

    Karp, J S; Muehllehner, G

    1985-07-01

    The spatial resolution of a NaI(T1), 25 mm thick bar detector designed for use in positron emission tomography has been studied. The position along the 500 mm long detector is determined from the centroid of the light distribution in the crystal as measured by a linear array of photomultiplier tubes. A Monte Carlo computer simulation was performed to investigate the factors limiting the spatial resolution. The program allowed us to study the effect of various phototube configurations and crystal surfaces. Since the resolution is affected by the width of the light distribution, we studied the effect of sharpening the distribution by modifying the front crystal surface with grooves cut perpendicular to the long axis of the crystal and by using non-linear preamplifiers. The simulation predicts a spatial resolution (FWHM) of 3 mm with this crystal. Experimental measurements of spatial resolution were performed concurrently with the simulations. In particular, a modified grooved crystal was measured to have 4.0 mm spatial resolution, an improvement over the original crystal without grooves. With delay line pulse shortening, which increases the count rate capability of the detector, the grooved crystal was measured to have 5.5 mm spatial resolution. PMID:3895256

  2. A location system based on two-dimensional position sensitive detector used in interactive projection systems

    NASA Astrophysics Data System (ADS)

    Ni, Kai; Zhou, Qian; Chen, Liangjun; Sun, Peng; Xu, Honglei; Gao, Yuan; Ma, Jianshe; Li, Yi; Liu, Minxia

    2010-11-01

    The interactive projection systems have been widely used in people's life. Currently the major type is based on interactive whiteboard (IWB). In recent years, a new type based on CCD/CMOS sensor is greatly developed. Compared to IWB, CCD/CMOS implements non-contact sensing, which can use any surface as the projection screen. This makes them more flexible in many applications. However, the main defect is that the location accuracy and tracing speed are limited by the resolution and frame rate of the CCD/CMOS. In this paper, we introduced our recent progress on constructing a new type of non-contact interactive projection system by using a two-dimensional position sensitive detector (PSD). The PSD is an analog optoelectronic position sensor utilizing photodiode surface resistance, which provides continuous position measuring and features high position resolution (better than 1.5μm) and high speed response (less than 1μs). By using the PSD, both high positioning resolution and high tracing speed can be easily achieved. A specially designed pen equipped with infrared LEDs is used as a cooperative target. A high precision signal processing system is designed and optimized. The nonlinearity of the PSD as well as the aberration of the camera lens is carefully measured and calibrated. Several anti-interference methods and algorithms are studied. Experimental results show that the positioning error is about 2mm over a 1200mm×1000mm projection screen, and the sampling rate is at least 100Hz.

  3. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    PubMed Central

    George, Lovya; Jain, Sunil K.

    2015-01-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  4. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip-Cleft Palate.

    PubMed

    George, Lovya; Jain, Sunil K

    2015-10-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  5. Continuous non-invasive monitoring improves blood pressure stability in upright position: randomized controlled trial.

    PubMed

    Benes, Jan; Simanova, Alena; Tovarnicka, Tereza; Sevcikova, Silvie; Kletecka, Jakub; Zatloukal, Jan; Pradl, Richard; Chytra, Ivan; Kasal, Eduard

    2015-02-01

    Intermittent blood pressure (BP) monitoring is the standard-of-care during low and intermediate risk anaesthesia, yet it could lead to delayed recognition of BP fluctuations. Perioperative hypotension is known to be associated with postoperative complications. Continuous, non-invasive methods for BP monitoring have been developed recently. We have tested a novel non-invasive, continuous monitor (using the volume clamp method) to assist with maintaining BP in safe ranges for patients undergoing surgery in a beach chair position. Forty adult patients undergoing thyroid gland surgery in an upright position were included in this prospective randomised controlled trial. Patients were equally allocated to the group with continuous monitoring of BP using the CNAP® Monitor and to the control group managed using an intermittent oscillometric BP cuff. The absolute and proportional time spent outside the range of ±20% of the target BP along with other hemodynamic and clinical parameters were evaluated. The continuous monitoring decreased the anaesthesia time spent below -20% pressure range [absolute: 12 min (4-20) vs. 27 min (16-34); p=0.001; relative to procedure length: 14% (7-20) vs. 33.5% (17.5-53); p=0.003]. No significant differences were observed in postoperative morbidity or in hospital length of stay. Continuous non-invasive BP monitoring via the CNAP® Monitor allows for better BP management in patients undergoing surgery in a beach chair position. In our randomised trial the time spent in hypotension was significantly shorter using continuous monitoring. PMID:24841333

  6. A Study of Position-Sensitive Solid-State Photomultiplier Signal Properties

    PubMed Central

    Schmall, Jeffrey P.; Du, Junwei; Judenhofer, Martin S.; Dokhale, Purushottam; Christian, James; McClish, Mickel; Shah, Kanai S.; Cherry, Simon R.

    2014-01-01

    We present an analysis of the signal properties of a position-sensitive solid-state photomultiplier (PS-SSPM) that has an integrated resistive network for position sensing. Attractive features of PS-SSPMs are their large area and ability to resolve small scintillator crystals. However, the large area leads to a high detector capacitance, and in order to achieve high spatial resolution a large network resistor value is required. These inevitably create a low-pass filter that drastically slows what would be a fast micro-cell discharge pulse. Significant changes in the signal shape of the PS-SSPM cathode output as a function of position are observed, which result in a position-dependent time delay when using traditional time pick-off methods such as leading edge discrimination and constant fraction discrimination. The timing resolution and time delay, as a function of position, were characterized for two different PS-SSPM designs, a continuous 10 mm × 10 mm PS-SSPM and a tiled 2 × 2 array of 5 mm × 5 mm PS-SSPMs. After time delay correction, the block timing resolution, measured with a 6 × 6 array of 1.3 × 1.3 × 20 mm3 LSO crystals, was 8.6 ns and 8.5 ns, with the 10 mm PS-SSPM and 5 mm PS-SSPM respectively. The effect of crystal size on timing resolution was also studied, and contrary to expectation, a small improvement was measured when reducing the crystal size from 1.3 mm to 0.5 mm. Digital timing methods were studied and showed great promise for allowing accurate timing by implementation of a leading edge time pick-off. Position-dependent changes in signal shape on the anode side also are present, which complicates peak height data acquisition methods used for positioning. We studied the effect of trigger position on signal amplitude, flood histogram quality, and depth-of-interaction resolution in a dual-ended readout detector configuration. We conclude that detector timing and positioning can be significantly improved by implementation of digital timing

  7. A Study of Position-Sensitive Solid-State Photomultiplier Signal Properties.

    PubMed

    Schmall, Jeffrey P; Du, Junwei; Judenhofer, Martin S; Dokhale, Purushottam; Christian, James; McClish, Mickel; Shah, Kanai S; Cherry, Simon R

    2014-06-12

    We present an analysis of the signal properties of a position-sensitive solid-state photomultiplier (PS-SSPM) that has an integrated resistive network for position sensing. Attractive features of PS-SSPMs are their large area and ability to resolve small scintillator crystals. However, the large area leads to a high detector capacitance, and in order to achieve high spatial resolution a large network resistor value is required. These inevitably create a low-pass filter that drastically slows what would be a fast micro-cell discharge pulse. Significant changes in the signal shape of the PS-SSPM cathode output as a function of position are observed, which result in a position-dependent time delay when using traditional time pick-off methods such as leading edge discrimination and constant fraction discrimination. The timing resolution and time delay, as a function of position, were characterized for two different PS-SSPM designs, a continuous 10 mm × 10 mm PS-SSPM and a tiled 2 × 2 array of 5 mm × 5 mm PS-SSPMs. After time delay correction, the block timing resolution, measured with a 6 × 6 array of 1.3 × 1.3 × 20 mm(3) LSO crystals, was 8.6 ns and 8.5 ns, with the 10 mm PS-SSPM and 5 mm PS-SSPM respectively. The effect of crystal size on timing resolution was also studied, and contrary to expectation, a small improvement was measured when reducing the crystal size from 1.3 mm to 0.5 mm. Digital timing methods were studied and showed great promise for allowing accurate timing by implementation of a leading edge time pick-off. Position-dependent changes in signal shape on the anode side also are present, which complicates peak height data acquisition methods used for positioning. We studied the effect of trigger position on signal amplitude, flood histogram quality, and depth-of-interaction resolution in a dual-ended readout detector configuration. We conclude that detector timing and positioning can be significantly improved by implementation of digital timing

  8. Use of SCALE Continuous-Energy Monte Carlo Tools for Eigenvalue Sensitivity Coefficient Calculations

    SciTech Connect

    Perfetti, Christopher M; Rearden, Bradley T

    2013-01-01

    The TSUNAMI code within the SCALE code system makes use of eigenvalue sensitivity coefficients for an extensive number of criticality safety applications, such as quantifying the data-induced uncertainty in the eigenvalue of critical systems, assessing the neutronic similarity between different critical systems, and guiding nuclear data adjustment studies. The need to model geometrically complex systems with improved fidelity and the desire to extend TSUNAMI analysis to advanced applications has motivated the development of a methodology for calculating sensitivity coefficients in continuous-energy (CE) Monte Carlo applications. The CLUTCH and Iterated Fission Probability (IFP) eigenvalue sensitivity methods were recently implemented in the CE KENO framework to generate the capability for TSUNAMI-3D to perform eigenvalue sensitivity calculations in continuous-energy applications. This work explores the improvements in accuracy that can be gained in eigenvalue and eigenvalue sensitivity calculations through the use of the SCALE CE KENO and CE TSUNAMI continuous-energy Monte Carlo tools as compared to multigroup tools. The CE KENO and CE TSUNAMI tools were used to analyze two difficult models of critical benchmarks, and produced eigenvalue and eigenvalue sensitivity coefficient results that showed a marked improvement in accuracy. The CLUTCH sensitivity method in particular excelled in terms of efficiency and computational memory requirements.

  9. Effect of prior deformation on sensitization development in stainless steel during continuous cooling

    SciTech Connect

    Simmons, J.W.; Atteridge, D.G.; Bruemmer, S.M. . Dept. of Materials Science and Engineering)

    1991-09-01

    Continuous cooling sensitization (CCS) occurs in austenitic stainless steel (SS) weldment HAZs where the material is subjected to weld-induced plastic deformation, and non-linear heating and cooling cycles. The primary purpose of this investigation was to quantitatively determine the effects of prior deformation on CCS. In addition, these results were used to develop a CCS data base for comparison to a recently published sensitization prediction model (SSDOS). Continuous cooling thermal cycling of specimens from high-carbon Type 316 SSs was performed in a computer-controlled Gleeble thermal simulator. The degree of sensitization (DOS) of thermally treated specimens was quantitatively measured using the electrochemical potentiokinetic reactivation (EPR) test. Prior deformation significantly enhanced the rate of CCS development in the Type 316 SS material. The DOS increased with increasing amounts of prior strain and decreasing cooling rates. Sensitization response was also sensitive to peak cycle temperatures. Continuous cooling sensitization development occurred primarily in the critical temperature range between about 900 and 750{degree}C. Peak cycle temperatures of 1000 and 1050{degree}C retarded sensitization development during subsequent continuous cooling. Strain recovery at elevated temperatures played an important role in reducing the effectiveness of prior deformation in accelerating sensitization kinetics. Due to the effects of recovery, in certain cases, prior strain values of 20% were only as effective as 10% in increasing the rate of sensitization development. Limited transgranular carbide precipitation was observed in 20% prior strain samples depending on specific thermal cycle parameters but was not a significant factor in the present work. The SSDOS model consistently overpredicted the CCS development in both heats of 316 SS studied, regardless of material condition (i.e. mill-annealed, solution-annealed, and pre-strained materials).

  10. Field evaluation of the modular azimuth and positioning system (MAPS) for a continuous mining machine

    SciTech Connect

    Sammarco, J.J. )

    1993-01-01

    This report details the testing and evaluation of a modular azimuth and positioning system (MAPS) to provide navigational information for a continuous mining machine. Vehicle navigation is part of the U.S. Bureau of Mines research program in computer-assisted mining serving as a tool to increase mining health, safety, and productivity. The Bureau is investigating other navigation systems, but MAPS seems to have the most promise. MAPS was installed on a continuous mining machine. An operator used the machine to cut coal while researchers collected machine and MAPS data. A comparison of MAPS data for xy position and data obtained with an electronic transit showed an increasing error for MAPS. After 30 min of operation, the easting position error was [minus]0.02 m, and the northing position error was 0.019 m; after 60 min of operation, the easting position error was [minus]0.19 m, and the northing position error was [minus]0.26 m. Modifications to MAPS software and to the operational procedure of the machine significantly reduced this error by a factor of 3.7. Researchers continue to reduce these errors.

  11. Methodology, verification, and performance of the continuous-energy nuclear data sensitivity capability in MCNP6

    SciTech Connect

    Kiedrowski, B. C.; Brown, F. B.

    2013-07-01

    A continuous-energy sensitivity coefficient capability has been introduced into MCNP6. The methods for generating energy-resolved and energy-integrated sensitivity profiles are discussed. Results from the verification exercises that were performed are given, and these show that MCNP6 compares favorably with analytic solutions, direct density perturbations, and comparisons to TSUNAMI-3D and MONK. Run-time and memory requirements are assessed for typical applications, and these are shown to be reasonable with modern computing resources. (authors)

  12. Hurler's syndrome with cor pulmonale secondary to obstructive sleep apnoea treated by continuous positive airway pressure.

    PubMed

    Chan, D; Li, A M; Yam, M C; Li, C K; Fok, T F

    2003-01-01

    A 6-year-old boy with Hurler's syndrome presented with right heart failure and pulmonary hypertension secondary to severe obstructive sleep apnoea. Both his sleep apnoea and cor pulmonale were effectively controlled with continuous positive airway pressure therapy. PMID:12969215

  13. A system to generate simultaneous forced oscillation and continuous positive airway pressure.

    PubMed

    Farré, R; Rotger, M; Montserrat, J M; Navajas, D

    1997-06-01

    Assessment of airway obstruction in patients with obstructive sleep apnoea (OSA) subjected to continuous positive airway pressure (CPAP) may be carried out using the forced oscillation technique (FOT). To facilitate routine application of forced oscillation (FO) in sleep studies, our aim was to design a system capable of generating CPAP and applying FOT simultaneously. We constructed a prototype CPAP + FO generator by connecting a specially designed electromagnetic valve in parallel with a conventional blower. The capacity of the prototype to generate forced oscillation (5 Hz +/- 1 hPa) was tested by connecting it to a model simulating spontaneous breathing. The response of the prototype for target CPAPs of 5, 10 and 15 hPa and imposed sinusoidal breathing with peak flow up to 0.75 L x s(-1) was excellent when compared with that reported for commercially available CPAP generators. The applicability of the prototype was tested by applying it to assess airway obstruction in four patients with OSA during sleep. We conclude that the generator designed is able to apply continuous positive airway pressure and forced oscillation simultaneously. The system could be useful for automatic and noninvasive assessment of airway obstruction in patients with obstructive sleep apnoea subjected to continuous positive airway pressure. Future development of the generator may be helpful in implementing a set-up for automatic titration of continuous positive airway pressure. PMID:9192942

  14. Motivational Interviewing (MINT) Improves Continuous Positive Airway Pressure (CPAP) Acceptance and Adherence: A Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Olsen, Sara; Smith, Simon S.; Oei, Tian P. S.; Douglas, James

    2012-01-01

    Objective: Adherence to continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) is poor. We assessed the effectiveness of a motivational interviewing intervention (motivational interview nurse therapy [MINT]) in addition to best practice standard care to improve acceptance and adherence to CPAP therapy in people with…

  15. Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks.

    PubMed

    Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

    2016-01-01

    To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning. PMID:27608019

  16. Development of continuous-energy eigenvalue sensitivity coefficient calculation methods in the shift Monte Carlo Code

    SciTech Connect

    Perfetti, C.; Martin, W.; Rearden, B.; Williams, M.

    2012-07-01

    Three methods for calculating continuous-energy eigenvalue sensitivity coefficients were developed and implemented into the Shift Monte Carlo code within the SCALE code package. The methods were used for two small-scale test problems and were evaluated in terms of speed, accuracy, efficiency, and memory requirements. A promising new method for calculating eigenvalue sensitivity coefficients, known as the CLUTCH method, was developed and produced accurate sensitivity coefficients with figures of merit that were several orders of magnitude larger than those from existing methods. (authors)

  17. POSITION SENSITIVE GERMANIUM DETECTORS FOR GAMMA-RAY IMAGING AND SPECTROSCOPY

    EPA Science Inventory

    Gamma-ray imaging with position-sensitive germanium detectors offers the advantages of excellent energy resolution, high detection efficiency, and potentially good sptial resolution. The development of the amorphous-semiconductor electrical contact technology for germanium detec...

  18. Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter

    NASA Technical Reports Server (NTRS)

    Smith, Stephen J.

    2007-01-01

    We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.

  19. The Effects of Sleep Continuity Disruption on Positive Mood and Sleep Architecture in Healthy Adults

    PubMed Central

    Finan, Patrick H.; Quartana, Phillip J.; Smith, Michael T.

    2015-01-01

    Objective: The purpose of this study was to test an experimental model of the effects of sleep continuity disturbance on sleep architecture and positive mood in order to better understand the mechanisms linking insomnia and depression. Design: Participants were randomized to receive 3 consecutive nights of sleep continuity disruption via forced nocturnal awakenings (FA, n = 21), or one of two control conditions: restricted sleep opportunity (RSO, n = 17) or uninterrupted sleep (US, n = 24). Setting: The study was set in an inpatient clinical research suite. Participants: Healthy, good-sleeping men and women were included. Measurement and Results: Polysomnography was used to measure sleep architecture, and mood was assessed via self-report each day. Compared to restricted sleep opportunity controls, forced awakenings subjects had significantly less slow wave sleep (P < 0.05) after the first night of sleep deprivation, and significantly lower positive mood (P < 0.05) after the second night of sleep deprivation. The differential change in slow wave sleep statistically mediated the observed group differences in positive mood (P = 0.002). Conclusions: To our knowledge, this is the first human experimental study to demonstrate that, despite comparable reductions in total sleep time, partial sleep loss from sleep continuity disruption is more detrimental to positive mood than partial sleep loss from delaying bedtime, even when controlling for concomitant increases in negative mood. With these findings, we provide temporal evidence in support of a putative biologic mechanism (slow wave sleep deficit) that could help explain the strong comorbidity between insomnia and depression. Citation: Finan PH, Quartana PJ, Smith MT. The effects of sleep continuity disruption on positive mood and sleep architecture in healthy adults. SLEEP 2015;38(11):1735–1742. PMID:26085289

  20. Ant colony optimization algorithm for continuous domains based on position distribution model of ant colony foraging.

    PubMed

    Liu, Liqiang; Dai, Yuntao; Gao, Jinyu

    2014-01-01

    Ant colony optimization algorithm for continuous domains is a major research direction for ant colony optimization algorithm. In this paper, we propose a distribution model of ant colony foraging, through analysis of the relationship between the position distribution and food source in the process of ant colony foraging. We design a continuous domain optimization algorithm based on the model and give the form of solution for the algorithm, the distribution model of pheromone, the update rules of ant colony position, and the processing method of constraint condition. Algorithm performance against a set of test trials was unconstrained optimization test functions and a set of optimization test functions, and test results of other algorithms are compared and analyzed to verify the correctness and effectiveness of the proposed algorithm. PMID:24955402

  1. Development of Position-Sensitive Magnetic Calorimeters for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Bandler, SImon; Stevenson, Thomas; Hsieh, Wen-Ting

    2011-01-01

    Metallic magnetic calorimeters (MMC) are one of the most promising devices to provide very high energy resolution needed for future astronomical x-ray spectroscopy. MMC detectors can be built to large detector arrays having thousands of pixels. Position-sensitive magnetic (PoSM) microcalorimeters consist of multiple absorbers thermally coupled to one magnetic micro calorimeter. Each absorber element has a different thermal coupling to the MMC, resulting in a distribution of different pulse shapes and enabling position discrimination between the absorber elements. PoSMs therefore achieve the large focal plane area with fewer number of readout channels without compromising spatial sampling. Excellent performance of PoSMs was achieved by optimizing the designs of key parameters such as the thermal conductance among the absorbers, magnetic sensor, and heat sink, as well as the absorber heat capacities. Micro fab ri - cation techniques were developed to construct four-absorber PoSMs, in which each absorber consists of a two-layer composite of bismuth and gold. The energy resolution (FWHM full width at half maximum) was measured to be better than 5 eV at 6 keV x-rays for all four absorbers. Position determination was demonstrated with pulse-shape discrimination, as well as with pulse rise time. X-ray microcalorimeters are usually designed to thermalize as quickly as possible to avoid degradation in energy resolution from position dependence to the pulse shapes. Each pixel consists of an absorber and a temperature sensor, both decoupled from the cold bath through a weak thermal link. Each pixel requires a separate readout channel; for instance, with a SQUID (superconducting quantum interference device). For future astronomy missions where thousands to millions of resolution elements are required, having an individual SQUID readout channel for each pixel becomes difficult. One route to attaining these goals is a position-sensitive detector in which a large continuous or

  2. A position sensitive time of flight detector for heavy ion ERD

    NASA Astrophysics Data System (ADS)

    Eschbaumer, S.; Bergmaier, A.; Dollinger, G.

    2016-03-01

    A new 2D position sensitive time of flight detector for heavy ion ERD has been developed. The detector features separate time and position measurement in a straight geometry. An electrostatic lens focuses the secondary electrons ejected from a carbon foil onto a channel plate stack maintaining the position information despite the electron momentum distribution. For position readout a 2D Backgammon anode is used. A position resolution of <0.6 mm (FWHM) and a time resolution of 96 ps (FWHM) is demonstrated.

  3. Seafloor horizontal positioning from a continuously operating buoy-based GPS-acoustic array

    NASA Astrophysics Data System (ADS)

    Chadwell, C. D.; Brown, K. M.; Tryon, M. D.; Send, U.

    2009-12-01

    Seafloor horizontal positions in a global frame were estimated daily from an autonomous buoy operating continuously over several months. The buoy (GEOCE) was moored offshore San Diego in 100-m-deep waters above an array of 4 seafloor transponders. Dual-frequency GPS data were collected at 1-Hz at a main antenna on the buoy and at 3 shore stations to provide continuous 2-3 cm positions of the buoy main antenna. Two single-frequency antennas on the buoy along with the main antenna were used to estimate the buoy attitude and short-term velocity. At one minute intervals the two-way acoustic travel time was measured between the buoy and transponders. During this few second span when transmitting and receiving acoustic signals, 10-Hz attitude and velocity were collected to locate the position of the transducer mounted approximately 2 m below the water line. The GPS and acoustic data were recorded internally and transmitted to shore over a cell-phone link and/or a wireless Ethernet. GPS data were combined with the acoustic data to estimate the array location at 1 minute intervals. The 1-minute positions are combined to provide a daily estimate of the array position. The buoy is autonomous, solar-powered and in addition to the GPS and acoustic data collects air pressure, temperature, wind speed/direction as well as water level at the surface and conductivity and temperature along the mooring line from near the sea surface to just above the sea floor. Here we report results from the horizontal positioning effort from Phase I of the project in shallow waters. The project also includes a vertical deformation sensor and physical oceanographic monitoring. A deep water (nominally 1000 m) test is planned for 2010. This work is supported by NSF-OCE-0551363 of the Ocean Technology and Interdisciplinary Coordination Program.

  4. K-Eigenvalue sensitivities of secondary distributions of continuous-energy data

    SciTech Connect

    Kiedrowski, B. C.; Brown, F. B.

    2013-07-01

    MCNP6 has the capability to produce energy-resolved sensitivity profiles for secondary distributions (fission {Chi} and scattering laws). Computing both unconstrained and constrained profiles are possible. Verification is performed with analytic test problems and a comparison to TSUNAMI-3D, and the comparisons show MCNP6 calculates correct or consistent results. Continuous-energy calculations are performed for three fast critical experiments: Jezebel, Flattop, and copper-reflected Zeus. The sensitivities to the secondary distributions (integrated over chosen energy ranges) are of similar magnitude to those of many of the cross sections, demonstrating the possibility that integral experiments are useful for assessing the fidelity of these data as well. (authors)

  5. Effects of rider position on continuous wave Doppler responses to maximal cycle ergometry.

    PubMed

    Franke, W D; Betz, C B; Humphrey, R H

    1994-03-01

    Using 10 well-trained (VO2peak = 60.6 ml kg-1min-1) college age cyclists and continuous wave Doppler echocardiography, peak acceleration (PkA) and velocity (PkV) of blood flow in the ascending aorta, and the stroke velocity integral (SVI) were assessed to determine if rider position influenced the central haemodynamic responses to graded maximal cycle ergometry. Cyclist position was determined by hand placement on the uprights (UPRI) or drops (DROP) of conventional handlebars or using aerodynamic handlebars (AHB). All subjects consistently achieved a peak workload of 300 W. The Doppler variables did not differ significantly between rider positions at each stage of the maximal exercise tests but did change in response to increasing workloads. PkA was significantly (P < 0.05) greater at workloads > or = 240 W versus < or = 120 W. PkV increased significantly (P < 0.05) up to 180 W and then reached a plateau. SVI increased to a workload of 120 W and then progressively declined, becoming significantly (P < 0.05) less at 300 W. For each stage, neither submaximal VO2, VI nor heart rate (HR) differed significantly between each trial. These results suggest that rider position does not affect the physiological response to maximal bicycle ergometry as responses to each position are similar. PMID:8044492

  6. Linear motor drive system for continuous-path closed-loop position control of an object

    DOEpatents

    Barkman, William E.

    1980-01-01

    A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.

  7. Effects of rider position on continuous wave Doppler responses to maximal cycle ergometry.

    PubMed Central

    Franke, W D; Betz, C B; Humphrey, R H

    1994-01-01

    Using 10 well-trained (VO2peak = 60.6 ml kg-1min-1) college age cyclists and continuous wave Doppler echocardiography, peak acceleration (PkA) and velocity (PkV) of blood flow in the ascending aorta, and the stroke velocity integral (SVI) were assessed to determine if rider position influenced the central haemodynamic responses to graded maximal cycle ergometry. Cyclist position was determined by hand placement on the uprights (UPRI) or drops (DROP) of conventional handlebars or using aerodynamic handlebars (AHB). All subjects consistently achieved a peak workload of 300 W. The Doppler variables did not differ significantly between rider positions at each stage of the maximal exercise tests but did change in response to increasing workloads. PkA was significantly (P < 0.05) greater at workloads > or = 240 W versus < or = 120 W. PkV increased significantly (P < 0.05) up to 180 W and then reached a plateau. SVI increased to a workload of 120 W and then progressively declined, becoming significantly (P < 0.05) less at 300 W. For each stage, neither submaximal VO2, VI nor heart rate (HR) differed significantly between each trial. These results suggest that rider position does not affect the physiological response to maximal bicycle ergometry as responses to each position are similar. PMID:8044492

  8. A Beta-Particle Hodoscope Constructed Using Scintillating Optical Fibers and Position Sensitive Photomultiplier Tubes

    SciTech Connect

    Orrell, John L.; Aalseth, Craig E.; Day, Anthony R.; Fast, Jim; Hossbach, Todd W.; Lidey, Lance S.; Ripplinger, Mike D.; Schrom, Brian T.

    2006-09-19

    A hodoscopic detector was constructed using a position-sensitive plastic scintillator active area to determine the location of beta-active micron-sized particulates on air filters. The ability to locate beta active particulates on airsample filters is a tool for environmental monitoring of anthropogenic production of radioactive material. A robust, field-deployable instrument can provide localization of radioactive particulate with position resolution of a few millimeters. The detector employs a novel configuration of scintillating plastic elements usually employed at much higher charged particle energies. A filter is placed on this element for assay. The detector is intended to be sensitive to activity greater than 1 Bq. The physical design, position reconstruction method, and expected detector sensitivity are reported.

  9. Bubble continuous positive airway pressure in a human immunodeficiency virus-infected infant

    PubMed Central

    McCollum, E. D.; Smith, A.; Golitko, C. L.

    2014-01-01

    SUMMARY World Health Organization-classified very severe pneumonia due to Pneumocystis jirovecii infection is recognized as a life-threatening condition in human immunodeficiency virus (HIV) infected infants. We recount the use of nasal bubble continuous positive airway pressure (BCPAP) in an HIV-infected African infant with very severe pneumonia and treatment failure due to suspected infection with P. jirovecii. We also examine the potential implications of BCPAP use in resource-poor settings with a high case index of acute respiratory failure due to HIV-related pneumonia, but limited access to mechanical ventilation. PMID:21396221

  10. Residual Daytime Sleepiness in Obstructive Sleep Apnea After Continuous Positive Airway Pressure Optimization: Causes and Management.

    PubMed

    Chapman, Julia L; Serinel, Yasmina; Marshall, Nathaniel S; Grunstein, Ronald R

    2016-09-01

    Excessive daytime sleepiness (EDS) is common in obstructive sleep apnea (OSA), but it is also common in the general population. When sleepiness remains after continuous positive airway pressure (CPAP) treatment of OSA, comorbid conditions or permanent brain injury before CPAP therapy may be the cause of the residual sleepiness. There is currently no broad approach to treating residual EDS in patients with OSA. Individual assessment must be made of comorbid conditions and medications, and of lifestyle factors that may be contributing to the sleepiness. Modafinil and armodafinil are the only pharmacologic agents indicated for residual sleepiness in these patients. PMID:27542881

  11. Single-point position and transition defects in continuous time quantum walks

    PubMed Central

    Li, Z. J.; Wang, J. B.

    2015-01-01

    We present a detailed analysis of continuous time quantum walks (CTQW) with both position and transition defects defined at a single point in the line. Analytical solutions of both traveling waves and bound states are obtained, which provide valuable insight into the dynamics of CTQW. The number of bound states is found to be critically dependent on the defect parameters, and the localized probability peaks can be readily obtained by projecting the state vector of CTQW on to these bound states. The interference between two bound states are also observed in the case of a transition defect. The spreading of CTQW probability over the line can be finely tuned by varying the position and transition defect parameters, offering the possibility of precision quantum control of the system. PMID:26323855

  12. Sex differences in risk sensitivity under positive and negative budgets and predictors of choice.

    PubMed

    Island, Heide K Deditius; Szalda-Petree, Allen D; Kucera, Stephanie C

    2007-10-01

    The authors investigated sex differences in human risk sensitivity by using a computerized choice task with an energy budget analogue. In addition, they explored possible personality predictors of variance sensitivity. The authors modified the traditional energy budget model from those used in risk-sensitive foraging research with nonhuman animals for appropriate use with a human population. Participants chose between 2 computer icons, 1 yielding a fixed-point reward and the other offering variable points. Men were risk prone in the negative budget and risk averse in the positive budget. Women were risk averse in the negative budget. Personality was not predictive of risk-sensitive bias. Interpreting the results using an evolutionary model, the authors found support for a biological and environmental construct of risk-sensitive behavior. PMID:18183739

  13. Microtubules continuously dictate distribution of actin filaments and positioning of cell cleavage in grasshopper spermatocytes.

    PubMed

    Alsop, G Bradley; Zhang, Dahong

    2004-03-15

    We systematically examined the impact of microtubules on distribution of actin filaments and positioning of cell cleavage using micromanipulation to progressively alter the symmetric distribution of spindle microtubules in grasshopper spermatocytes. The initial microtubule asymmetry was induced by placing a single chromosome at one spindle pole using a microneedle, which facilitates regional assembly of spindle microtubules. We augmented chromosome-induced microtubule asymmetry by further removing the aster from the achromosomal pole, producing unichromosome-bearing monopolar spindles. We created the highest spindle asymmetry by cutting early anaphase cells in two, each containing a full set of segregating chromosomes in a half-spindle. We demonstrate that the location of the spindle midzone, distribution of actin filaments, and position of cell cleavage depend on the amount of microtubule asymmetry generated, shifting up to 48.6+/-3.8% away from the spindle equator in cut cells. The positional shift is dynamic, changing incessantly as spindle microtubules reorganize during cytokinesis. These results suggest that microtubules continuously dictate the distribution of actin filaments and positioning of cell cleavage in grasshopper spermatocytes. PMID:15020685

  14. Position-sensitive detection of slow neutrons: Survey of fundamental principles

    SciTech Connect

    Crawford, R.K.

    1992-07-01

    This paper sets forth the fundamental principles governing the development of position-sensitive detection systems for slow neutrons. Since neutrons are only weakly interacting with most materials, it is not generally practical to detect slow neutrons directly. Therefore all practical slow neutron detection mechanisms depend on the use of nuclear reactions to ``convert`` the neutron to one or more charged particles, followed by the subsequent detection of the charged particles. The different conversion reactions which can be used are discussed, along with the relative merits of each. This is followed with a discussion of the various methods of charged particle detection, how these lend themselves to position-sensitive encoding, and the means of position encoding which can be applied to each case. Detector performance characteristics which may be of importance to the end user are discussed and related to these various detection and position-encoding mechanisms.

  15. Position-sensitive detection of slow neutrons: Survey of fundamental principles

    SciTech Connect

    Crawford, R.K.

    1992-01-01

    This paper sets forth the fundamental principles governing the development of position-sensitive detection systems for slow neutrons. Since neutrons are only weakly interacting with most materials, it is not generally practical to detect slow neutrons directly. Therefore all practical slow neutron detection mechanisms depend on the use of nuclear reactions to convert'' the neutron to one or more charged particles, followed by the subsequent detection of the charged particles. The different conversion reactions which can be used are discussed, along with the relative merits of each. This is followed with a discussion of the various methods of charged particle detection, how these lend themselves to position-sensitive encoding, and the means of position encoding which can be applied to each case. Detector performance characteristics which may be of importance to the end user are discussed and related to these various detection and position-encoding mechanisms.

  16. Unconventional double bent-crystal diffractometer equipped by position-sensitive detector

    NASA Astrophysics Data System (ADS)

    Mikula, Pavel; Lukas, Petr; Kulda, Jiri; Strunz, Pavel; Saroun, Jan; Wagner, Volker; Scherm, Reinhard; Alefeld, Berthold; Reinartz, Richard

    1992-11-01

    Using Bragg diffraction optics, an unconventional DBC diffractometer was tested for medium resolution small-angle neutron scattering experiments. The diffraction geometry of the analyzer enables to transform the angular beam distribution into the positional distribution and, consequently, to analyze it by means of a one-dimensional position sensitive detector. First experimental results obtained with a sample of PE+graphite proves a compatibility and a higher speed of data collection compared to a standard DBC diffractometer.

  17. Effects of Continuous Positive Airway Pressure on Neurocognitive Function in Obstructive Sleep Apnea Patients: The Apnea Positive Pressure Long-term Efficacy Study (APPLES)

    PubMed Central

    Kushida, Clete A.; Nichols, Deborah A.; Holmes, Tyson H.; Quan, Stuart F.; Walsh, James K.; Gottlieb, Daniel J.; Simon, Richard D.; Guilleminault, Christian; White, David P.; Goodwin, James L.; Schweitzer, Paula K.; Leary, Eileen B.; Hyde, Pamela R.; Hirshkowitz, Max; Green, Sylvan; McEvoy, Linda K.; Chan, Cynthia; Gevins, Alan; Kay, Gary G.; Bloch, Daniel A.; Crabtree, Tami; Dement, William C.

    2012-01-01

    Study Objective: To determine the neurocognitive effects of continuous positive airway pressure (CPAP) therapy on patients with obstructive sleep apnea (OSA). Design, Setting, and Participants: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial conducted at 5 U.S. university, hospital, or private practices. Of 1,516 participants enrolled, 1,105 were randomized, and 1,098 participants diagnosed with OSA contributed to the analysis of the primary outcome measures. Intervention: Active or sham CPAP Measurements: Three neurocognitive variables, each representing a neurocognitive domain: Pathfinder Number Test-Total Time (attention and psychomotor function [A/P]), Buschke Selective Reminding Test-Sum Recall (learning and memory [L/M]), and Sustained Working Memory Test-Overall Mid-Day Score (executive and frontal-lobe function [E/F]) Results: The primary neurocognitive analyses showed a difference between groups for only the E/F variable at the 2 month CPAP visit, but no difference at the 6 month CPAP visit or for the A/P or L/M variables at either the 2 or 6 month visits. When stratified by measures of OSA severity (AHI or oxygen saturation parameters), the primary E/F variable and one secondary E/F neurocognitive variable revealed transient differences between study arms for those with the most severe OSA. Participants in the active CPAP group had a significantly greater ability to remain awake whether measured subjectively by the Epworth Sleepiness Scale or objectively by the maintenance of wakefulness test. Conclusions: CPAP treatment improved both subjectively and objectively measured sleepiness, especially in individuals with severe OSA (AHI > 30). CPAP use resulted in mild, transient improvement in the most sensitive measures of executive and frontal-lobe function for those with severe disease, which suggests the existence of a complex OSA-neurocognitive relationship

  18. 78 FR 59983 - Submission for Review: Information Collection 3206-NEW; Questionnaire for Non-Sensitive Positions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-30

    ...Federal Investigative Services (FIS), U. S. Office of Personnel Management (OPM) offers the general public and other Federal agencies the opportunity to comment on an information collection request (ICR), Office of Management and Budget (OMB) Control No. 3206-NEW, for Questionnaire for Non-Sensitive Positions, Standard Form 85 (SF 85). As required by the Paperwork Reduction Act of 1995, (Pub.......

  19. Sensitivity to Social Contingency and Positive Emotion in 2-Month-Olds

    ERIC Educational Resources Information Center

    Soussignan, Robert; Nadel, Jacqueline; Canet, Pierre; Gerardin, Priscille

    2006-01-01

    This study was aimed at sorting out conflicting results in the literature concerning 2-month-olds' sensitivity to interpersonal contingency, and investigated the potential role of infants' positive emotion in contingency detection. Infants were randomly assigned to an experimental group (EG) that was presented an uninterrupted live-replay-live…

  20. 3D position estimation using an artificial neural network for a continuous scintillator PET detector

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Zhu, W.; Cheng, X.; Li, D.

    2013-03-01

    Continuous crystal based PET detectors have features of simple design, low cost, good energy resolution and high detection efficiency. Through single-end readout of scintillation light, direct three-dimensional (3D) position estimation could be another advantage that the continuous crystal detector would have. In this paper, we propose to use artificial neural networks to simultaneously estimate the plane coordinate and DOI coordinate of incident γ photons with detected scintillation light. Using our experimental setup with an ‘8 + 8’ simplified signal readout scheme, the training data of perpendicular irradiation on the front surface and one side surface are obtained, and the plane (x, y) networks and DOI networks are trained and evaluated. The test results show that the artificial neural network for DOI estimation is as effective as for plane estimation. The performance of both estimators is presented by resolution and bias. Without bias correction, the resolution of the plane estimator is on average better than 2 mm and that of the DOI estimator is about 2 mm over the whole area of the detector. With bias correction, the resolution at the edge area for plane estimation or at the end of the block away from the readout PMT for DOI estimation becomes worse, as we expect. The comprehensive performance of the 3D positioning by a neural network is accessed by the experimental test data of oblique irradiations. To show the combined effect of the 3D positioning over the whole area of the detector, the 2D flood images of oblique irradiation are presented with and without bias correction.

  1. Impact of Treatment with Continuous Positive Airway Pressure (CPAP) on Weight in Obstructive Sleep Apnea

    PubMed Central

    Quan, Stuart F.; Budhiraja, Rohit; Clarke, Denise P.; Goodwin, James L.; Gottlieb, Daniel J.; Nichols, Deborah A.; Simon, Richard D.; Smith, Terry W.; Walsh, James K.; Kushida, Clete A.

    2013-01-01

    Study Objective: To determine the impact of continuous positive airway pressure (CPAP) on weight change in persons with obstructive sleep apnea (OSA). Design, Setting, and Participants: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blinded sham-controlled multicenter clinical trial conducted at 5 sites in the United States. Of 1,105 participants with an apnea hypopnea index ≥ 10 events/ hour initially randomized, 812 had body weight measured at baseline and after 6 months of study. Intervention: CPAP or Sham CPAP. Measurements: Body weight, height, hours of CPAP or Sham CPAP use, Epworth Sleepiness Scale score. Results: Participants randomized to CPAP gained 0.35 ± 5.01 kg, whereas those on Sham CPAP lost 0.70 ± 4.03 kg (mean ± SD, p = 0.001). Amount of weight gain with CPAP was related to hours of device adherence, with each hour per night of use predicting a 0.42 kg increase in weight. This association was not noted in the Sham CPAP group. CPAP participants who used their device ≥ 4 h per night on ≥ 70% of nights gained the most weight over 6 months in comparison to non-adherent CPAP participants (1.0 ± 5.3 vs. -0.3 ± 5.0 kg, p = 0.014). Conclusions: OSA patients using CPAP may gain a modest amount of weight with the greatest weight gain found in those most compliant with CPAP. Commentary: A commentary on this article appears in this issue on page 995. Citation: Quan SF; Budhiraja R; Clarke DP; Goodwin JL; Gottlieb DJ; Nichols DA; Simon RD; Smith TW; Walsh JK; Kushida CA. Impact of treatment with continuous positive airway pressure (CPAP) on weight in obstructive sleep apnea. J Clin Sleep Med 2013;9(10):989-993. PMID:24127141

  2. Centroid position measurements and subpixel sensitivity variations with the MAMA detector

    NASA Technical Reports Server (NTRS)

    Morgan, Jeffrey S.; Slater, D. C.; Timothy, John G.; Jenkins, E. B.

    1989-01-01

    Initial measurements of the position sensitivity of a visible-light multianode microchannel array detector show that centroid calculations for image spots are accurate to better than 0.04 pixels even with sources that are essentially delta functions at the photocathode.Subpixel sensitivity variations of 10-15 percent are typically found for pixels in the array. Variations as large as 30 percent are possible in the worst conditions. These variations limit the photometric accuracy of the detector when very small scale features are observed. The photometric accuracy and the position sensitivity of the detector appear to be limited by cross-coupling effects within the anode array. Initial measurements with more recent designs of the detector show that most or all of this cross-coupling has been eliminated.

  3. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  4. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  5. Characterization of multilayer reflectors and position sensitive detectors in the 45--300 A region

    SciTech Connect

    Yamashita, K.; Takahashi, S. ); Kitamoto, S.; Takahama, S.; Tamura, K. ); Hatsukade, I. ); Sakurai, M. ); Watanabe, M. ); Yamaguchi, A. ); Nagata, H.; Ohtani, M. )

    1992-01-01

    Multilayer reflectors and position sensitive detectors have been developed in constructing imaging optical systems in the 45--300 A region. Molybdenum-silicon (2{ital d}=140 A, {ital N}=20) and nickel--carbon (2{ital d}=100 A, {ital N}=20) multilayers were deposited on a spherical mirror (25 cm in diameter) for the normal incidence and on a segment of paraboloidal mirror (20 cm{times}10 cm) for 30{degree} grazing incidence. Their optical characteristics were evaluated by using characteristic x rays and monochromatized synchrotron radiation in the 45--300 A region. A position sensitive detector is made of a tandem microchannel plate (MCP) with a CsI photocathode and resistive plate, which is placed at the focal plane of each mirror. The detection efficiency and position resolution were measured by using characteristic x rays of C{ital K}{alpha} and monochromatized synchrotron radiation in the 45--200 A region.

  6. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.; Sato, K.; Sato, S.; Suzuki, S.

    2013-12-01

    As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments.

  7. Positioning Continuing Education: Boundaries and Intersections between the Domains Continuing Education, Knowledge Translation, Patient Safety and Quality Improvement

    ERIC Educational Resources Information Center

    Kitto, Simon; Bell, Mary; Peller, Jennifer; Sargeant, Joan; Etchells, Edward; Reeves, Scott; Silver, Ivan

    2013-01-01

    Public and professional concern about health care quality, safety and efficiency is growing. Continuing education, knowledge translation, patient safety and quality improvement have made concerted efforts to address these issues. However, a coordinated and integrated effort across these domains is lacking. This article explores and discusses the…

  8. Investigation of the hygienic safety of continuous positive airways pressure devices after reprocessing.

    PubMed

    Steinhauer, K; Goroncy-Bermes, P

    2005-10-01

    With the widespread use of continuous positive airways pressure (CPAP) therapy, the safety of CPAP devices after reprocessing is the subject of debate. In this study, the contamination of CPAP devices and the effectiveness of disinfection was investigated. A total of 122 CPAP devices were examined including 50 CPAP devices used by patients, which were examined before and after reprocessing. Seventy-two new CPAP devices that had not been in contact with patients served as controls. The results of this study show that the microbial contamination of new and used CPAP devices is only minimal. Contaminating micro-organisms were predominantly micro-organisms reflecting the normal environmental microflora such as Penicillium spp., Aspergillus spp., Micrococcaceae and Bacillaceae. Gram-negative species could only be found in rare cases. The data obtained give no indication of poor disinfection of CPAP devices. PMID:16023258

  9. Nonexistence of entangled continuous-variable Werner states with positive partial transpose

    NASA Astrophysics Data System (ADS)

    McNulty, Daniel; Tatham, Richard; Mišta, Ladislav

    2014-03-01

    We address an open question about the existence of entangled continuous-variable (CV) Werner states with positive partial transpose (PPT). We prove that no such state exists by showing that all PPT CV Werner states are separable. The separability follows by observing that these CV Werner states can be approximated by truncating the states into a finite-dimensional convex mixture of product states. In addition, the constituents of the product states comprise a generalized non-Gaussian measurement which gives, rather surprisingly, a strictly tighter upper bound on quantum discord than photon counting. These results uncover the presence of only negative partial transpose entanglement and illustrate the complexity of more general nonclassical correlations in this paradigmatic class of genuine non-Gaussian quantum states.

  10. [Continuous positive airway pressure treatment in sleep-related respiratory disorders in children].

    PubMed

    Estivill Sancho, Eduard; Miró, Núria Roure

    2010-12-01

    Continuous positive airway pressure (CPAP) is the first choice in the treatment of apnea-hypopnea syndrome in adults and, in recent years, is considered the second option after surgery in children. CPAP is the best option in children if apnea-hypopnea syndrome persists after surgery. For many professionals in the field, the use of CPAP in all ages of children and adolescents is safe, effective and well tolerated. Follow-up visits are required every 6-12 months, since the mask pressure and size requirements will change depending on children's growth and development. The success of the use of CPAP is closely related to children's tolerance of the CPAP mask. Many professionals have described strategies to improve this tolerance. One of these strategies is to use behavioral therapy, which has been shown be effective in increasing tolerance and performance of the CPAP. PMID:21354498

  11. Early Bubble Continuous Positive Airway Pressure: Investigating Interprofessional Best Practices for the NICU Team.

    PubMed

    Casey, Jessica L; Newberry, Desi; Jnah, Amy

    2016-01-01

    Premature neonates delivered <32 completed weeks gestation are unprepared to handle the physiologic demands of extrauterine life. Within the respiratory system, alveolar instability and collapse can cause decreased functional residual capacity, impaired oxygenation, and hypoxemia leading to respiratory distress syndrome. Supportive measures are indicated immediately after birth to establish physiologic stability including bubble continuous positive airway pressure (CPAP) or endotracheal intubation and mechanical ventilation. CPAP is a noninvasive, gentle mode of ventilation that can mitigate the effects of lung immaturity, but prolonged use can increase the risk for nasal breakdown. Strategies to mitigate this risk must be infused as best practices in the NICU environment. The purpose of this article is to propose an evidence-based best practice care bundle for the early initiation of CPAP in the delivery room and associated skin barrier protection strategies for premature neonates <32 weeks gestation and weighing <1,500 g. PMID:27194606

  12. Standardized weaning of infants <32 weeks of gestation from continuous positive airway pressure - a feasibility study.

    PubMed

    Kidszun, André; Plate, Maren; Arnold, Christine; Winter, Julia; Gerhold-Ay, Aslihan; Mildenberger, Eva

    2016-10-01

    The practice of weaning premature infants from continuous positive airway pressure (CPAP) varies considerably and is usually performed without written standards. In this study, the feasibility of a standardized weaning approach was evaluated. In a quasi-experimental design, data from a prospective, post-intervention cohort (n=41) were compared to data from a pre-intervention cohort (n=36). Standardized weaning was feasible but no significant differences in short-term respiratory outcomes were observed. Weaning from CPAP was achieved at 32.1 ± 1.6 (post-intervention) versus 32.5 ± 2.3 weeks (pre-intervention) postmenstrual age. More rigorous, large-scale clinical trials are necessary before firm recommendations on distinct weaning regimens can be made. PMID:26552715

  13. Development of position sensitive scintillation counter for balloon-borne hard x-ray telescope

    NASA Astrophysics Data System (ADS)

    Tamura, Keisuke; Kunieda, Hideyo; Ogasaka, Yasushi; Furuzawa, Akihiro; Shibata, Ryo; Nakamura, Tomokazu; Ohnishi, Katsuhiko; Kanou, Yasufumi; Miyata, Emi; Tsunemi, Hiroshi

    2006-06-01

    We have been developing position sensitive scintillation counter as focal plane detector of hard X-ray telescope onboard a balloon borne experiment. This detector consists NaI(TI) scintillator and position sensitive photo-multiplier tube. Focal plane detector has to have high efficiency in hard X-ray region, enough position resolution and detection area. 3mm thickness of NaI(TI) scintillator can achieve almost 100% efficiency below 80 keV. We measured position resolved energy and position resolution in synchrotron radiation facility SPring-8 BL20B2. Position resolution of 2.4mm at 60keV is about half of plate scale of half power diameter of X-ray telescope. The detector has 6 cm diameter window and it corresponds to 25 arcmin field of view, and it is enough lager than the that of telescope, which is 12 arcmin in FWHM. Balloon borne experiment for observation of the background was performed on May 24, 2005 from Sanriku balloon center. We could obtain background data for 3 hours at altitude of 40 km.

  14. Adjoint sensitivity method for the downward continuation of the Earth's geomagnetic field through an electrically conducting mantle

    NASA Astrophysics Data System (ADS)

    Hagedoorn, J. M.; Martinec, Z.

    2012-12-01

    Recent models of the Earth's geomagnetic field at the core-mantle boundary (CMB) are based on satellite measurements and/or observatory data, which are mostly harmonically downward continued to the CMB. One aim of the upcoming satellite mission Swarm is to determine the three-dimensional distribution of electric conductivity of the Earth's mantle. On this background, we developed an adjoint sensitivity downward continuation approach that is capable to consider three-dimensional electric conductivity distributions. Martinec (Geophys. J. Int., 136, 1999) developed a time-domain spectral-finite element approach for the forward modelling of vector electromagnetic induction data as measured on ground-based magnetic observatory or by satellites. We design a new method to compute the sensitivity of the magnetic induction data to a magnetic field prescribed at the core-mantle boundary, which we term the adjoint sensitivity method. The forward and adjoint initial boundary-value problems, both solved in the time domain, are identical, except for the specification of prescribed boundary conditions. The respective boundary-value data are the measured X magnetic component for the forward method and the difference between the measured and predicted Z magnetic component for the adjoint method. The squares of the differences in Z magnetic component summed up over the time of observation and all spatial positions of observations determine the misfit. Then the sensitivities of observed data, i.e. the partial derivatives of the misfit with respect to the parameters characterizing the magnetic field at the core-mantle boundary, are obtained by the surface integral over the core-mantle boundary of the product of the adjoint solution multiplied by the time-dependent functions describing the time variability of magnetic field at the core-mantle boundary, and integrated over the time of observation. The time variability of boundary data is represented in terms of locally supported B

  15. Safety and effectiveness of bubble continuous positive airway pressure in preterm neonates with respiratory distress

    PubMed Central

    Mathai, S.S.; Rajeev, A.; Adhikari, K.M.

    2014-01-01

    Background Studies on Bubble Continuous Positive Airway Pressure (B-CPAP) as respiratory support for neonates are few. The aim of our study was to determine the efficacy and safety of B-CPAP in preterm neonates requiring respiratory support. Methods A prospective observation study was done on 50 preterm babies requiring respiratory support for mild to moderate respiratory distress. Support was given with short, nasal cannulae. Surfactant was administered when indicated. Monitoring was done clinically, with pulse oximeter, radiologically and with blood gases. Staff members were also asked their views. Follow-up was done for 3 months. Results The mean gestational age was 32.46 (+3.23) weeks and mean birth weight 1454.4 (+487.42) g. Respiratory Distress Syndrome was the commonest indication (30/50). The mean maximum pressure was 6.04 cm H2O and mean maximum FiO2 was 72.16%. Mean maximum paO2, paCO2 and mean minimum paCO2 were 92.93 mm Hg (+16.97), 52.36 mm Hg (+ 7.78) and 36.46 mm Hg (+ 4.95) respectively. Early initiation resulted in lesser duration of support. Failure rate was 30%. Apnoea, >1 dose surfactant and late initiation had a statistically higher incidence of failure. Main complications were skin abrasions (30%), feed intolerance (26%) and gastric distension (26%). Survival rate was 94%. 68% of staff felt that it was as easy to use and 88% felt it was more reliable than standard CPAP. Conclusions Bubble Continuous Positive Airway Pressure is safe, efficacious and easy to use in preterm neonates with mild to moderate respiratory distress. PMID:25382905

  16. Development of a one-dimensional Position Sensitive Detector for tracking applications

    NASA Astrophysics Data System (ADS)

    Lydecker, Leigh Kent, IV

    Optical Position Sensitive Detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS processing, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. Because they are non-contact, they do not degrade over time from surface friction due to repetitive sliding motion associated with standard full contact sliding potentiometers. This results in long, reliable device lifetimes. In this work, an innovative PSD was developed to replace the linear hard contact potentiometer currently being used in a human-computer interface architecture. First, a basic lateral effect PSD was developed to provide real-time positioning of the mouthpiece used in the interface architecture which tracks along a single axis. During the course of this work, multiple device geometries were fabricated and analyzed resulting in a down selection of a final design. This final device design was then characterized in terms of resolution and responsivity and produced in larger quantities as initial prototypes for the test product integration. Finally, an electronic readout circuit was developed in order to interface the dual- line lateral effect PSD developed in this thesis with specifications required for product integration. To simplify position sensing, an innovative type of optical position sensor was developed using a linear photodiodes with back-to-back connections. This so- called Self-Balancing Position Sensitive Detector (SBPSD) requires significantly fewer processing steps than the basic lateral effect position sensitive detector discussed above and eliminates the need for external readout circuitry entirely. Prototype devices were fabricated in this work, and the performance characteristics of these devices were established paving the way for ultimate integration into the target product as well as additional applications.

  17. Position-sensitive detectors of the detector group at Jülich

    NASA Astrophysics Data System (ADS)

    Engels, R.; Clemens, U.; Kemmerling, G.; Nöldgen, H.; Schelten, J.

    2009-06-01

    The detector group of the Central Institute of Electronics at the Forschungszentrum Jülich GmbH was founded in 1968. First developments aimed at a detector system with a position-sensitive BF 3 proportional counter for small-angle neutron scattering, which was later used at a beamline of the research reactor FRJ2. At the end of the 1970s first measurements were carried out with photomultiplier (PM)-based detector systems linked with a LiI crystal from Harshaw. Based on this experience we started with the spectrum of position-sensitive neutron scintillation detectors, which have been developed and designed in our institute during the last three decades comprising several high-resolution linear and two-dimensional detectors. The general design of those detectors is based on a modified Anger principle using an array of PMs and a 1 mm 6Li glass scintillator. The sensitive detector area varies on the type of the PMs used and is related to the spatial resolution of the detector type. The neutron sensitivity at 1 Å is about 65% and the remaining gamma sensitivity is less than 10 -4 with a maximum count rate up to 500 kHz depending on the used detector system.

  18. Performance characteristics of a compact position-sensitive LSO detector module.

    PubMed

    Vaquero, J J; Seidel, J; Siegel, S; Gandler, W R; Green, M V

    1998-12-01

    We assembled a compact detector module comprised of an array of small, individual crystals of lutetium oxyorthosilicate:Ce (LSO) coupled directly to a miniature, metal-can, position-sensitive photomultiplier tube (PSPMT). We exposed this module to sources of 511-keV annihilation radiation and beams of 30- and 140-keV photons and measured spatial linearity; spatial variations in module gain, energy resolution, and event positioning; coincidence timing; the accuracy and sensitivity of identifying the crystal-of-first-interaction at 511 keV; and the effects of intercrystal scatter and LSO background radioactivity. The results suggest that this scintillator/phototube combination should be highly effective in the coincidence mode and can be used, with some limitations, to image relatively low-energy single photon emitters. Photons that are completely absorbed on their first interaction at 511 keV are positioned by the module at the center of a crystal. Intercrystal scatter events, even those that lead to total absorption of the incident photon, are placed by the module in a regular "connect-the-dot" pattern that joins crystal centers. As a result, the accuracy of event positioning can be made to exceed 90%, though at significantly reduced sensitivity, by retaining only events that occur within small regions-of-interest around each crystal center and rejecting events that occur outside these regions in the connect-the-dot pattern. PMID:10048853

  19. Front-end circuit for position sensitive silicon and vacuum tube photomultipliers with gain control and depth of interaction measurement

    NASA Astrophysics Data System (ADS)

    Herrero, Vicente; Colom, Ricardo; Gadea, Rafael; Lerche, Christoph W.; Cerdá, Joaquín; Sebastiá, Ángel; Benlloch, José M.

    2007-06-01

    Silicon Photomultipliers, though still under development for mass production, may be an alternative to traditional Vacuum Photomultipliers Tubes (VPMT). As a consequence, electronic front-ends initially designed for VPMT will need to be modified. In this simulation, an improved architecture is presented which is able to obtain impact position and depth of interaction of a gamma ray within a continuous scintillation crystal, using either kind of PM. A current sensitive preamplifier stage with individual gain adjustment interfaces the multi-anode PM outputs with a current division resistor network. The preamplifier stage allows to improve front-end processing delay and temporal resolution behavior as well as to increase impact position calculation resolution. Depth of interaction (DOI) is calculated from the width of the scintillation light distribution, which is related to the sum of voltages in resistor network input nodes. This operation is done by means of a high-speed current mode scheme.

  20. Position sensitive x-ray spectrophotometer using microwave kinetic inductance detectors

    SciTech Connect

    Mazin, Benjamin A.; Bumble, Bruce; Day, Peter K.; Eckart, Megan E.; Golwala, Sunil; Zmuidzinas, Jonas; Harrison, Fiona A.

    2006-11-27

    The surface impedance of a superconductor changes when energy is absorbed and Cooper pairs are broken to produce single electron (quasiparticle) excitations. This change may be sensitively measured using a thin-film resonant circuit called a microwave kinetic inductance detector (MKID). The practical application of MKIDs for photon detection requires a method of efficiently coupling the photon energy to the MKID. The authors present results on position sensitive x-ray detectors made by using two aluminum MKIDs on either side of a tantalum photon absorber strip. Diffusion constants, recombination times, and energy resolution are reported. MKIDs can easily be scaled into large arrays.

  1. Position sensitive x-ray spectrophotometer using microwave kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Mazin, Benjamin A.; Bumble, Bruce; Day, Peter K.; Eckart, Megan E.; Golwala, Sunil; Zmuidzinas, Jonas; Harrison, Fiona A.

    2006-11-01

    The surface impedance of a superconductor changes when energy is absorbed and Cooper pairs are broken to produce single electron (quasiparticle) excitations. This change may be sensitively measured using a thin-film resonant circuit called a microwave kinetic inductance detector (MKID). The practical application of MKIDs for photon detection requires a method of efficiently coupling the photon energy to the MKID. The authors present results on position sensitive x-ray detectors made by using two aluminum MKIDs on either side of a tantalum photon absorber strip. Diffusion constants, recombination times, and energy resolution are reported. MKIDs can easily be scaled into large arrays.

  2. The usage of the Boussignac continuous positive airway pressure system in acute respiratory failure.

    PubMed

    Wong, D T; Tam, A D; Van Zundert, T C R V

    2013-05-01

    Traditionally, continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP) devices have been used to treat patients in acute respiratory failure. However they require an electric power source, are relatively large in size, and may be difficult to use in prehospital settings. The recently introduced Boussignac CPAP system is capable of delivering 10 cmH2O of CPAP, is compact, portable and requires only an oxygen source. This paper reviews the efficacy of using Boussignac CPAP as a treatment for acute respiratory failure in both prehospital and hospital settings. All studies mainly focused on patients treated for cardiogenic pulmonary edema. In the prehospital setting, Boussigac CPAP significantly improved respiratory parameters and oxygenation from baseline values. In the emergency department setting, Boussignac CPAP was more effective than standard oxygen delivery and just as effective as BiPAP in improving patient oxygenation and respiration. In one study, implementing Boussignac CPAP reduced intubation rate and hospital stay. Most hospital staff found Boussignac CPAP easy to use and complication rates were low. Boussigac CPAP is a useful device in the treatment of patients with acute respiratory failure, especially in the prehospital setting. PMID:23419338

  3. Positional Stability of Electromagnetic Transponders Used for Prostate Localization and Continuous, Real-Time Tracking

    SciTech Connect

    Litzenberg, Dale W. . E-mail: litzen@umich.edu; Willoughby, Twyla R. M.Sc.; Balter, James M.; Sandler, Howard M.; Wei, John; Kupelian, Patrick A.; Cunningham, Alexis A.; Bock, Andrea; Aubin, Michele; Roach, Mack; Shinohara, Katsuto; Pouliot, Jean

    2007-07-15

    Purpose: To determine the relative positional stability of implanted glass-encapsulated circuits (transponders) used in continuous electromagnetic localization and tracking of target volumes during radiation therapy. Ideally, the distances between transponders remains constant over the course of treament. In this work, we evaluate the accuracy of these conditions. Methods and Materials: Three transponders were implanted in each of 20 patients. Images (CT scan or X-ray pair) were acquired at 13 time points. These images occurred from the day of implant (2 weeks before simulation) to 4 weeks posttreatment. The distance between transponders was determined from each dataset. The average and standard deviation of each distance were determined, and changes were evaluated over several time periods, including pretreatment and during therapy. Results: Of 60 transponders implanted, 58 showed no significant migration from their intended positions. Of the two transponders that did migrate, one appears to have been implanted in the venous plexus, and the other in the urethra, with no clinical consequences to the patients. An analysis that included the planning CT scan and all subsequent distance measurements showed that the standard deviation of intertransponder distances was {<=}1.2 mm for up to 1 month after the completion of therapy. Conclusions: Implanted transponders demonstrate the same long-term stability characteristics as implanted gold markers, within statistical uncertainties. As with gold markers, and using the same implant procedure, basic guidelines for the placement of transponders within the prostate help ensure minimal migration.

  4. An ultra-sensitive wearable accelerometer for continuous heart and lung sound monitoring.

    PubMed

    Hu, Yating; Xu, Yong

    2012-01-01

    This paper presents a chest-worn accelerometer with high sensitivity for continuous cardio-respiratory sound monitoring. The accelerometer is based on an asymmetrical gapped cantilever which is composed of a bottom mechanical layer and a top piezoelectric layer separated by a gap. This novel structure helps to increase the sensitivity by orders of magnitude compared with conventional cantilever based accelerometers. The prototype with a resonant frequency of 1100Hz and a total weight of 5 gram is designed, constructed and characterized. The size of the prototype sensor is 35mm×18mm×7.8mm (l×w×t). A built-in charge amplifier is used to amplify the output voltage of the sensor. A sensitivity of 86V/g and a noise floor of 40ng/√Hz are obtained. Preliminary tests for recording both cardiac and respiratory signals are carried out on human body and the new sensor exhibits better performance compared with a high-end electronic stethoscope. PMID:23365987

  5. A multiplex readout method for position sensitive boron coated straw neutron detector

    NASA Astrophysics Data System (ADS)

    Yu, Hao; Gong, Hui; Li, Jianmin; Wang, Yongqiang; Wang, Xuewu; Li, Yuanjing; Kang, Kejun

    2015-10-01

    A 1 m×1 m boron coated straw neutron detector is expected to be used to build the small-angle neutron scattering (SANS) instrument of the Compact Pulsed Hadron Source (CPHS) in Tsinghua University. A multiplex readout method based on summing circuits in columns and rows is studied for this large area position sensitive detector. In this method, the outputs of charge sensitive preamplifiers are combined by columns and rows at two ends of the detector, and then the shaped signals are sampled by flash ADCs. With the position reconstructed algorithm implemented in FPGA which analyzes the charge division and column and row number of signals, the 3-D position information of neutron events can be obtained. The position resolution and counting rate performance of this method are analyzed, and the comparison to the delay-line readout method is also given. With the multiplex readout method, the scale of readout electronics can be greatly reduced and a good position resolution can be reached. A readout electronics system for a detector module which consists 4 × 10 straw tubes is designed based on this method, and the test with neutron beam shows an average 3-D spatial resolution of 4 × 4 × 6.8mm3.

  6. Measurement of spot dancing for focused beam in atmosphere using position sensitive photomultiplier tube

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoshan; Zhu, Wenyue; Rao, Ruizhong

    2005-05-01

    The spot dancing of the focused laser beam in the turbulent atmosphere was studied using a two dimensional position sensitive photomultiplier tube (PSPMT). The centroid position of the laser spot was evaluated by means of current-dividing center-of-gravity detection. The system has advantage over detector array system in spatial resolution and over the imaging system in dynamic range and sampling rate. Laser propagation experiments were carried out over 1000m path above the sea level and the fluctuations of laser intensity were measured simultaneously. The frequency spectra were calculated by fast Fourier tansform and the standard deviation of the spot dancing were analyzed.

  7. Development of position sensitive proportional counters for hot particle detection in laundry and portal monitors

    SciTech Connect

    Shonka, J.J.; Schwahn, S.O.; Bennett, T.E.; Misko, D.J.

    1992-09-01

    This report summarizes research which demonstrates the use of position sensitive proportional counters in contamination monitoring systems. Both laundry monitoring and portal monitoring systems were developed. The laundry monitor was deployed at a nuclear power plant where it was used to monitor clothing during an outage. Position sensitive proportional counter based contamination monitoring systems were shown to have significant advantages over systems using conventional proportional counters. These advantages include the ability to directly measure the area and quantity of contamination. This capability permits identification of hot particles. These systems are also capable of self calibration via internal check sources. Systems deployed with this technology should benefit from reduced complexity, cost and maintenance. The inherent reduction of background that occurs when the counter is electronically divided into numerous detectors permits operation in high background radiation fields and improves detection limits over conventional technology.

  8. New position sensitive photomultiplier tubes for high energy physics and nuclear medical applications

    SciTech Connect

    Suzuki, S.; Matsushita, T.; Suzuki, T.; Kimura, S.; Kume, H.

    1988-02-01

    New position sensitive photomultiplier tubes with fine mesh structured dynodes and discrete anode array configurations have been developed. One kind of the position sensitive photomultiplier tubes is being used as a photodetector for High Enegy Physics applications in high magnetic field environments. A photomultiplier tube constructed with 88 Multi-Anodes has a spatial resolution of less than 2.6 mm in FWHM in a magnetic field with a density of 500-2000 Gauss. The resolution includes an anode width of 2.6 mm. Another type of Multi-Anode photomultiplier tube which has been developed is the detector with a high spatial resolution for such applications as the PET system and hodoscope in scintillation systems. The tube, by applying additional electro-focusing electrodes, has an intrinsic spatial resolution of 1.4 mm in FWHM without the magnetic field.

  9. Data acquisition system for an advanced x-ray imaging crystal spectrometer using a segmented position-sensitive detector.

    PubMed

    Nam, U W; Lee, S G; Bak, J G; Moon, M K; Cheon, J K; Lee, C H

    2007-10-01

    A versatile time-to-digital converter based data acquisition system for a segmented position-sensitive detector has been developed. This data acquisition system was successfully demonstrated to a two-segment position-sensitive detector. The data acquisition system will be developed further to support multisegmented position-sensitive detector to improve the photon count rate capability of the advanced x-ray imaging crystal spectrometer system. PMID:17979416

  10. High-sensitivity and high-dry-etching durability positive-type electron-beam resist

    NASA Astrophysics Data System (ADS)

    Tamura, Akira; Yonezawa, Masaji; Sato, Mitsuyoshi; Fujimoto, Yoshiaki

    1991-08-01

    As feature sizes of semiconductors grow smaller, a resist having dry etching durability and high sensitivity is required for electron beam lithography. However, the positive type electron beam resist having both high sensitivity and high dry etching durability, which suits for practical use, has not been developed yet. In order to solve this problem, a homologous series of poly(alkyl 2-cyanoacrylate) has been investigated. As a result, the new positive type electron beam resist having high sensitivity, high dry etching durability, and high thermal resistance has been developed. This new type of resist consists of poly(cyclohexyl 2- cyanoacrylate), and these features of this resist are due to the cyano and the cyclohexyl groups. The dry etching durability of this resist is 2.19 times as high as that of poly(mthyl methacrylate) (PMMA). The sensitivity is 1.7 (mu) C/cm2 at accelerating voltage of 20 kV, which is about the same as that of poly(butene-1-sulfone) (PBS). Moreover, poly(cyclohexyl 2-cyanoacrylate) has the glass transition of 152 degree(s)C, and then it is thermally stable. Using this resist in photomask fabrication by dry etching, the chrome linewidth uniformity of 0.034 micrometers 3 (sigma) can be obtained.

  11. Development of Position-sensitive Transition-edge Sensor X-ray Detectors

    NASA Technical Reports Server (NTRS)

    Smith, S. J.; Bandler, S. R.; Brekosky, R. P.; Brown, A.-D.; Chervenak, J. A.; Eckard, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. s.; Sad (eor. K/ E/); Figueroa-Feliciano, E.

    2008-01-01

    We report on the development of position-sensitive transition-edge sensors (PoST's) for future x-ray astronomy missions such as the International X-ray Observatory (IXO), currently under study by NASA and ESA. PoST's consist of multiple absorbers each with a different thermal coupling to one or more transition-edge sensor (TES). This differential thermal coupling between absorbers and TES's results in different characteristic pulse shapes and allows position discrimination between the different pixels. The development of PoST's is motivated by a desire to achieve maximum focal-plane area with the least number of readout channels and as such. PoST's are ideally suited to provide a focal-plane extension to the Constellation-X microcalorimeter array. We report the first experimental results of our latest one and two channel PoST's, which utilize fast thermalizing electroplated Au/Bi absorbers coupled to low noise Mo/Au TES's - a technology already successfully implemented in our arrays of single pixel TES's. We demonstrate 6 eV energy resolution coupled with spatial sensitivity in the keV energy range. We also report on the development of signal processing algorithms to optimize energy and position sensitivity of our detectors.

  12. An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones

    PubMed Central

    Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

    2015-01-01

    Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel “quasi-dynamic” Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the “process-level” fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move. PMID:26690447

  13. An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones.

    PubMed

    Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

    2015-01-01

    Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel "quasi-dynamic" Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the "process-level" fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move. PMID:26690447

  14. Reversibility of albuminuria and continuous positive airway pressure compliance in patients of obstructive sleep apnea syndrome.

    PubMed

    Chen, Ning-Hung; Chou, Yu-Ting; Lee, Pei-Hsien; Lin, Shih-Wei; Chuang, Li-Pang; Lin, Yu-Sheng; Yang, Cheng-Ta

    2016-06-01

    A positive correlation between albuminuria and severity of obstructive sleep apnea syndrome (OSAS) has been demonstrated, as indexed by urine albumin-to-creatinine ratios (UACRs). However, the effect of continuous positive airway pressure (CPAP) treatment on albuminuria in OSAS patients has not been established.Sixty subjects, with apnea-hypopnea indices >15 events per hour and no other diagnoses associated with albuminuria, underwent overnight polysomnography for sleep apnea and were examined for UACR at baseline and after 6 months of CPAP therapy. CPAP compliance rates were also recorded.Significant improvement in UACR was found in OSAS patients with good compliance to CPAP treatment after 6 months of therapy (baseline vs 6-month follow-up, 32.0 ± 9.5 vs 19.2 ± 6.5 mg/g, respectively, P = 0.007), whereas slight worsening in UACRs was noted in patients with poor compliance to CPAP treatment (baseline vs 6-month follow-up, respectively, 16.7 ± 4.4 vs 19.1 ± 6.3 mg/g, respectively, P = 0.39). Change in UACR was significant between poor compliance versus good compliance groups (2.4 ± 2.7 vs -12.8 ± 4.4 mg/g, respectively, t = 2.9, P = 0.005). A significant correlation between improvement in UACR and CPAP compliance rates was also noted (Spearman's correlation coefficient: -0.37, P = 0.007). Baseline UACR, good CPAP compliance, and body mass index were independent predictors of changes in UACR.Adequate CPAP treatment improves albuminuria in OSAS patients. In addition to monitoring CPAP adherence and subjective sleepiness, UACR may offer an objective physiological index of CPAP therapeutic effectiveness. PMID:27368036

  15. Continuous Positive Airway Pressure Compliance in Patients with Obstructive Sleep Apnea

    PubMed Central

    Afsharpaiman, Shahla; Vahedi, Encieh; Aqaee, Hossein

    2016-01-01

    Background: Obstructive sleep apnea (OSA) is a common condition in adults. In most cases, first-line therapy includes treatment with positive airway pressure devices. However, because of discomfort, continuous positive airway pressure (CPAP) compliance is often poor. To determine the willingness of patients to use CPAP device, the relationship of demographic and polysomnographic variables with tolerance and the willingness to use CPAP, was evaluated. Materials and Methods: In this cross-sectional study, 120 OSA patients who were treated with CPAP in Baqiyatallah Hospital, Tehran, Iran, were selected by convenience sampling. Polysomnographic variables, willingness to use CPAP for short and long periods of time and possible complications were evaluated. Results: One hundred-twenty cases with a mean age of 53±10.3 years were assessed. The mean Epworth Sleepiness Scale (ESS) score was 11.9 ± 6.2 in CPAP users versus 11.8±6.1 in patients who did not use CPAP. The willingness to use CPAP for short-term was significantly different between the two groups (P=0.008). The average minimum oxygen saturation rate of patients was 75.21% in CPAP users versus 71.63% in non CPAP users. Also, the average desaturation index was higher in CPAP users (54.5 vs. 44.98). The mean ESS was 14.03 ± 6.19 in those who accepted long-term treatment versus 8.85 ± 4.89 (P=0.003). Skin wounds and rhinitis were reported in 4.1% and 4.1% of patients, respectively. Conclusion: It is concluded that high CPAP compliance rates are achievable through comprehensive CPAP therapy.

  16. Reversibility of albuminuria and continuous positive airway pressure compliance in patients of obstructive sleep apnea syndrome

    PubMed Central

    Chen, Ning-Hung; Chou, Yu-Ting; Lee, Pei-Hsien; Lin, Shih-Wei; Chuang, Li-Pang; Lin, Yu-Sheng; Yang, Cheng-Ta

    2016-01-01

    Abstract A positive correlation between albuminuria and severity of obstructive sleep apnea syndrome (OSAS) has been demonstrated, as indexed by urine albumin-to-creatinine ratios (UACRs). However, the effect of continuous positive airway pressure (CPAP) treatment on albuminuria in OSAS patients has not been established. Sixty subjects, with apnea-hypopnea indices >15 events per hour and no other diagnoses associated with albuminuria, underwent overnight polysomnography for sleep apnea and were examined for UACR at baseline and after 6 months of CPAP therapy. CPAP compliance rates were also recorded. Significant improvement in UACR was found in OSAS patients with good compliance to CPAP treatment after 6 months of therapy (baseline vs 6-month follow-up, 32.0 ± 9.5 vs 19.2 ± 6.5 mg/g, respectively, P = 0.007), whereas slight worsening in UACRs was noted in patients with poor compliance to CPAP treatment (baseline vs 6-month follow-up, respectively, 16.7 ± 4.4 vs 19.1 ± 6.3 mg/g, respectively, P = 0.39). Change in UACR was significant between poor compliance versus good compliance groups (2.4 ± 2.7 vs −12.8 ± 4.4 mg/g, respectively, t = 2.9, P = 0.005). A significant correlation between improvement in UACR and CPAP compliance rates was also noted (Spearman's correlation coefficient: −0.37, P = 0.007). Baseline UACR, good CPAP compliance, and body mass index were independent predictors of changes in UACR. Adequate CPAP treatment improves albuminuria in OSAS patients. In addition to monitoring CPAP adherence and subjective sleepiness, UACR may offer an objective physiological index of CPAP therapeutic effectiveness. PMID:27368036

  17. Remaining or becoming secure: parental sensitive support predicts attachment continuity from infancy to adolescence in a longitudinal adoption study.

    PubMed

    Beijersbergen, Mariëlle D; Juffer, Femmie; Bakermans-Kranenburg, Marian J; van IJzendoorn, Marinus H

    2012-09-01

    In a longitudinal study with 125 early adopted adolescents, we examined continuity of attachment from infancy to adolescence and the role of parental sensitive support in explaining continuity or discontinuity of attachment. Assessments of maternal sensitive support and infant attachment (Strange Situation Procedure) were completed when infants were 12 months old. When the children were 14 years old, we observed mothers' sensitive support during a conflict discussion. The adolescents' attachment representations were assessed with the Adult Attachment Interview. Mothers of secure adolescents showed significantly more sensitive support during conflicts than did mothers of insecure adolescents. Overall, no continuity of attachment from infancy to adolescence was found. However, maternal sensitive support in early childhood and adolescence predicted continuity of secure attachment from 1 to 14 years, whereas less maternal sensitive support in early childhood but more maternal sensitive support in adolescence predicted children's change from insecurity in infancy to security in adolescence. We conclude that both early and later parental sensitive support are important for continuity of attachment across the first 14 years of life. PMID:22369333

  18. Polarization-sensitive optical coherence tomography using continuous polarization modulation with arbitrary phase modulation amplitude

    NASA Astrophysics Data System (ADS)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2012-03-01

    We demonstrate theoretically and experimentally that the phase retardance and relative optic-axis orientation of a sample can be calculated without prior knowledge of the actual value of the phase modulation amplitude when using a polarization-sensitive optical coherence tomography system based on continuous polarization modulation (CPM-PS-OCT). We also demonstrate that the sample Jones matrix can be calculated at any values of the phase modulation amplitude in a reasonable range depending on the system effective signal-to-noise ratio. This has fundamental importance for the development of clinical systems by simplifying the polarization modulator drive instrumentation and eliminating its calibration procedure. This was validated on measurements of a three-quarter waveplate and an equine tendon sample by a fiber-based swept-source CPM-PS-OCT system.

  19. Adherence to Continuous Positive Airway Pressure Treatment for Obstructive Sleep Apnea: Implications for Future Interventions

    PubMed Central

    Weaver, Terri E.; Sawyer, Amy M.

    2010-01-01

    Adherence to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA) is a critical problem with adherence rates ranging from 30–60%. Poor adherence to CPAP is widely recognized as a significant limiting factor in treating OSA, reducing the overall effectiveness of the treatment and leaving many OSA patients at heightened risk for comorbid conditions, impaired function and quality of life. The extant literature examining adherence to CPAP provides critical insight to measuring adherence outcomes, defining optimal adherence levels, and predicting CPAP adherence. This research has revealed salient factors that are associated with or predict CPAP adherence and may guide the development of interventions to promote CPAP adherence. Over the past 10 years, intervention studies to promote CPAP adherence have incorporated a multitude of strategies including education, support, cognitive behavioral approaches, and mixed strategies. This review of the current state of science of CPAP adherence will (1) synthesize the extant literature with regard to measuring, defining, and predicting CPAP adherence, (2) review published intervention studies aimed at promoting CPAP adherence, and (3) suggest directions for future empiric study of adherence to CPAP that will have implications for translational science. Our current understanding of CPAP adherence suggests that adherence is a multi-factorial, complex clinical problem that requires similarly designed approaches to effectively address poor CPAP adherence in the OSA population. PMID:20308750

  20. Increased airway reactivity in a neonatal mouse model of Continuous Positive Airway Pressure (CPAP)

    PubMed Central

    Mayer, Catherine A.; Martin, Richard J.; MacFarlane, Peter M.

    2015-01-01

    Background Continuous positive airway pressure (CPAP) is a primary form of respiratory support used in the intensive care of preterm infants, but its long-term effects on airway (AW) function are unknown. Methods We developed a neonatal mouse model of CPAP treatment to determine whether it modifies later AW reactivity. Un-anesthetized spontaneously breathing mice were fitted with a mask to deliver CPAP (6cmH2O, 3hrs/day) for 7 consecutive days starting at postnatal day 1. Airway reactivity to methacholine was assessed using the in vitro living lung slice preparation. Results One week of CPAP increased AW responsiveness to methacholine in male, but not female mice, compared to untreated control animals. The AW hyper-reactivity of male mice persisted for 2 weeks (at P21) after CPAP treatment ended. 4 days of CPAP, however, did not significantly increase AW reactivity. Females also exhibited AW hyper-reactivity at P21, suggesting a delayed response to early (7 days) CPAP treatment. The effects of 7 days of CPAP on hyper-reactivity to methacholine were unique to smaller AWs whereas larger ones were relatively unaffected. Conclusion These data may be important to our understanding of the potential long-term consequences of neonatal CPAP therapy used in the intensive care of preterm infants. PMID:25950451

  1. Nasal airway responses to nasal continuous positive airway pressure breathing: An in-vivo pilot study.

    PubMed

    White, David E; Bartley, Jim; Shakeel, Muhammad; Nates, Roy J; Hankin, Robin K S

    2016-06-14

    The nasal cycle, through variation in nasal airflow partitioning, allows the upper airway to accommodate the contrasting demands of air conditioning and removal of entrapped air contaminants. The purpose of this study was to investigate the influence of nasal continuous positive airway pressure (nCPAP) breathing has on both nasal airflow partitioning and nasal geometry. Using a custom-made nasal mask, twenty healthy participants had the airflow in each naris measured during normal nasal breathing followed by nCPAP breathing. Eight participants also underwent magnetic resonance imaging (MRI) of the nasal region during spontaneous nasal breathing, and then nCPAP breathing over a range of air pressures. During nCPAP breathing, a simultaneous reduction in airflow through the patent airway together with a corresponding increase in airway flow within the congested nasal airway were observed in sixteen of the twenty participants. Nasal airflow resistance is inversely proportional to airway cross-sectional area. MRI data analysis during nCPAP breathing confirmed airway cross-sectional area reduced along the patent airway while the congested airway experienced an increase in this parameter. During awake breathing, nCPAP disturbs the normal inter-nasal airflow partitioning. This could partially explain the adverse nasal drying symptoms frequently reported by many users of this therapy. PMID:27173595

  2. Tobacco industry litigation position on addiction: continued dependence on past views

    PubMed Central

    Henningfield, Jack E; Rose, Christine A; Zeller, Mitch

    2006-01-01

    This paper reviews the tobacco industry's litigation strategy for addressing the addiction issue through trial testimony by its experts, and opening and closing statements by its lawyers. Despite the fact that several companies now claim to accept, in varying degrees, the conclusions of the Surgeon General concerning tobacco addiction, the tobacco industry litigation strategy pertaining to addiction is essentially unchanged since that of the early 1980s when the issue emerged as crucial. The industry uses its experts and the process of cross‐examination of plaintiff's experts to imply that the addictiveness of tobacco and nicotine are more comparable to substances such as caffeine, chocolate, and even milk, than to heroin, cocaine and alcohol. Furthermore, the tobacco industry contends that the definition of addiction has now become so broadened as to include carrots and caffeine and hence that any concurrence that smoking is addictive, does not imply that cigarettes are addictive to the standards that drugs such as heroin and cocaine are addictive. Finally, the industry has continuously asserted that tobacco users assumed the risks of tobacco since they understood that quitting could be difficult when they began to use, and moreover, that the main barrier to cessation is lack of desire or motivation to quit and not physical addiction. These positions have been maintained through the 2004–2005 US Government litigation that was ongoing as the time of this writing. PMID:17130621

  3. Impact of Continuous Positive Airway Pressure on Cardiovascular Risk Factors in High-Risk Patients.

    PubMed

    Zhao, Ying Y; Redline, Susan

    2015-11-01

    Cardiovascular disease remains the leading cause of morbidity and mortality in developed countries. Obstructive sleep apnea is a highly prevalent condition characterized by repetitive upper airway collapse during sleep. A large body of evidence suggests that obstructive sleep apnea is associated with the development of cardiovascular disease and increased cardiovascular morbidity and mortality. Continuous positive airway pressure (CPAP) is the current gold standard for the treatment of obstructive sleep apnea. CPAP devices maintain upper airway patency using a pneumatic splint, thereby ameliorating the repetitive deoxygenation and reoxygenation characteristic of sleep in obstructive sleep apnea patients. Accumulating evidence suggests that CPAP treatment may lead to a reduction in blood pressure. Limited evidence also suggests that CPAP therapy may modulate glucose metabolism, serum cholesterol levels, and inflammatory biomarkers. Thus, CPAP treatment may be associated with cardiovascular risk factor modification in patients with obstructive sleep apnea, who are often obese and at an increased risk of developing cardiovascular disease. This review updates the knowledge on the effects of CPAP on cardiovascular risk factors from recently published randomized trials. PMID:26370408

  4. Bubble Continuous Positive Airway Pressure Enhances Lung Volume and Gas Exchange in Preterm Lambs

    PubMed Central

    Pillow, J. Jane; Hillman, Noah; Moss, Timothy J. M.; Polglase, Graeme; Bold, Geoff; Beaumont, Chris; Ikegami, Machiko; Jobe, Alan H.

    2007-01-01

    Rationale: The technique used to provide continuous positive airway pressure (CPAP) to the newborn may influence lung function and breathing efficiency. Objectives: To compare differences in gas exchange physiology and lung injury resulting from treatment of respiratory distress with either bubble or constant pressure CPAP and to determine if the applied flow influences short-term outcomes. Methods: Lambs (133 d gestation; term is 150 d) born via cesarean section were weighed, intubated, and treated with CPAP for 3 hours. Two groups were treated with 8 L/minute applied flow using the bubble (n = 12) or the constant pressure (n = 12) technique. A third group (n = 10) received the bubble method with 12 L/minute bias flow. Measurements at study completion included arterial blood gases, oxygraphy, capnography, tidal flow, multiple breath washout, lung mechanics, static pressure–volume curves, and bronchoalveolar lavage fluid protein. Measurements and Main Results: Birth weight and arterial gas variables at 15 minutes were comparable. Flow (8 or 12 L/min) did not influence the 3-hour outcomes in the bubble group. Bubble technique was associated with a higher pH, PaO2, oxygen uptake, and area under the flow–volume curve, and a decreased alveolar protein, respiratory quotient, PaCO2, and ventilation inhomogeneity compared with the constant pressure group. Conclusions: Compared with constant pressure technique, bubble CPAP promotes enhanced airway patency during treatment of acute postnatal respiratory disease in preterm lambs and may offer protection against lung injury. PMID:17431223

  5. A systematic review of continuous positive airway pressure for obstructive sleep apnoea-hypopnoea syndrome.

    PubMed

    McDaid, Catriona; Durée, Kate H; Griffin, Susan C; Weatherly, Helen L A; Stradling, John R; Davies, Robert J O; Sculpher, Mark J; Westwood, Marie E

    2009-12-01

    We conducted a systematic review of current evidence on the effectiveness of continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnoea-hypopnoea syndrome (OSAHS). The primary outcomes were subjective sleepiness, using Epworth Sleepiness Scale (ESS) and objective sleepiness using Maintenance of Wakefulness Test (MWT) and Multiple Sleep Latency Test (MSLT). Mean difference (MD) in endpoints was used to compare CPAP to usual care, placebo and dental devices. The analysis was stratified by symptom and disease severity at baseline. CPAP significantly reduced ESS score compared to control (MD -2.7, 95% CI -3.45, -1.96). The benefit was greatest in patients whose symptoms were severe at baseline: severely symptomatic population (MD -5.0, -6.5, -3.5); moderate (MD -2.3, -3.0, -1.6); mild (MD -1.1, -1.8, -0.3). CPAP significantly improved MWT score compared to control (MD 3.3, 1.3, 5.3) but not on the MSLT. There was no statistically significant difference between CPAP and dental devices on the ESS, MWT or MSLT, in a population with moderate symptoms. There was some evidence of benefit for blood pressure with CPAP compared to control. CPAP is an effective treatment for OSAHS in moderate to severe symptomatic patients and there may be benefits for mild symptoms. Dental devices may be a treatment option for moderate symptoms. PMID:19362029

  6. Otic Barotrauma Resulting from Continuous Positive Airway Pressure: Case Report and Literature Review

    PubMed Central

    McCormick, Justin P.; Hildrew, Douglas M.; Lawlor, Claire M.; Guittard, Jesse A.; Worley, N. Knight

    2016-01-01

    Background: Obstructive sleep apnea (OSA) is a growing problem affecting millions of people in the United States. The prevalence of OSA has risen drastically in the past few decades concurrently with the increasing prevalence of obesity. Subsequently, there has been an ever-increasing rise in the use of continuous positive airway pressure (CPAP) devices. While using CPAP devices may lead to many adverse effects, the majority of these effects are described as relatively benign. Case Report: We describe the detailed clinical course and outcome for a patient with otic barotrauma as a result of excessive self-titration of CPAP therapy in an in-home setting. We also discuss the pathophysiology of otic barotrauma and present a review of current literature on the topic. Conclusion: While the benefits of CPAP are clear, we must take into account the rare but possible effects on ear structure and function. Many studies describe an increase in middle ear pressure with the use of CPAP, but few describe the effects of this increased pressure on the middle ear, such as the otic barotrauma described in this case. Given the increased prevalence of OSA, it is important to understand the risks associated with CPAP therapy. PMID:27303224

  7. Development of arrays of position-sensitive microcalorimeters for Constellation-X

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    We are developing arrays of position-sensitive transition-edge sensor (POST) X-ray detectors for future astronomy missions such as NASA's Constellation-X. The POST consists of multiple absorbers thermally coupled to one or more transition-edge sensor (TES). Each absorber element has a different thermal coupling to the TES. This results in a distribution of different pulse shapes and enables position discrimination between the absorber elements. POST'S are motivated by the desire to achieve the largest possible focal plane area with the fewest number of readout channels and are ideally suited to increasing the Constellation-X focal plane area, without comprising on spatial sampling. Optimizing the performance of POST'S requires careful design of key parameters such as the thermal conductances between the absorbers, TES and the heat sink. as well as the absorber heat capacities. Using recently developed signal processing algorithms we have investigated the trade-off between position-sensitivity, energy resolution and pulse decay time. based on different device design parameters for PoST's. Our new generation of PoST's utilize technology successfully developed on high resolution (approximately 2.5eV) single pixels arrays of Mo/Au TESs. also under development for Constellation-X. This includes noise mitigation features on the TES and low resistivity electroplated absorbers. We report on the first experimental results from these new one and two-channel PoST"s, consisting of all Au and composite Au/Bi absorbers, which are designed to achieve an energy resolution of < 10 eV. coupled with count-rates of 100's per pixel per second and position sensitivity over the energy range 0.3-10 keV.

  8. In vivo dosimetry for gynaecological brachytherapy using a novel position sensitive radiation detector: Feasibility study

    SciTech Connect

    Reniers, B.; Landry, G.; Eichner, R.; Hallil, A.; Verhaegen, F.

    2012-04-15

    Purpose: In gynecological radiotherapy with high dose rate (HDR){sup 192}Ir brachytherapy, the treatment complexity has increased due to improved optimization techniques and dose constraints. As a consequence, it has become more important to verify the dose delivery to the target and also to the organs at risk (e.g., the bladder). In vivo dosimetry, where dosimeters are placed in or on the patient, is one way of verifying the dose but until recently this was hampered by motion of the radiation detectors with respect to the source. The authors present a novel dosimetry method using a position sensitive radiation detector. Methods: The prototype RADPOS system (Best Medical Canada) consists of a metal oxide field effect transistor (MOSFET) dosimeter coupled to a position-sensor, which deduces its 3D position in a magnetic field. To assess the feasibility of in vivo dosimetry based on the RADPOS system, different characteristics of the detector need to be investigated. Using a PMMA phantom, the positioning accuracy of the RADPOS system was quantified by comparing position readouts with the known position of the detector along the x and y-axes. RADPOS dose measurements were performed at various distances from a Nucletron{sup 192}Ir source in a PMMA phantom to evaluate the energy dependence of the MOSFET. A sensitivity analysis was performed by calculating the dose after varying (1) the position of the RADPOS detector to simulate organ motion and (2) the position of the first dwell position to simulate errors in delivery. The authors also performed an uncertainty analysis to determine the action level (AL) that should be used during in vivo dosimetry. Results: Positioning accuracy is found to be within 1 mm in the 1-10 cm range from the origin along the x-axis (away from the transmitter), meeting the requirements for in vivo dosimetry. Similar results are obtained for the other axes. The ALs are chosen to take into account the total uncertainty on the measurements. As a

  9. Sensitivity of regional forest carbon budgets to continuous and stochastic climate change pressures

    NASA Astrophysics Data System (ADS)

    Sulman, B. N.; Desai, A. R.; Scheller, R. M.

    2010-12-01

    Climate change is expected to impact forest-atmosphere carbon budgets through three processes: 1. Increased disturbance rates, including fires, mortality due to pest outbreaks, and severe storms 2. Changes in patterns of inter-annual variability, related to increased incidence of severe droughts and defoliating insect outbreaks 3. Continuous changes in forest productivity and respiration, related to increases in mean temperature, growing season length, and CO2 fertilization While the importance of these climate change effects in future regional carbon budgets has been established, quantitative characterization of the relative sensitivity of forested landscapes to these different types of pressures is needed. We present a model- and- data-based approach to understanding the sensitivity of forested landscapes to climate change pressures. Eddy-covariance and biometric measurements from forests in the northern United States were used to constrain two forest landscape models. The first, LandNEP, uses a prescribed functional form for the evolution of net ecosystem productivity (NEP) over the age of a forested grid cell, which is reset following a disturbance event. This model was used for investigating the basic statistical properties of a simple landscape’s responses to climate change pressures. The second model, LANDIS-II, includes different tree species and models forest biomass accumulation and succession, allowing us to investigate the effects of more complex forest processes such as species change and carbon pool accumulation on landscape responses to climate change effects. We tested the sensitivity of forested landscapes to these three types of climate change pressures by applying ensemble perturbations of random disturbance rates, distribution functions of inter-annual variability, and maximum potential carbon uptake rates, in the two models. We find that landscape-scale net carbon exchange responds linearly to continuous changes in potential carbon uptake and

  10. The position effect of electron-deficient quinoxaline moiety in porphyrin based sensitizers

    NASA Astrophysics Data System (ADS)

    Fan, Suhua; Lv, Kai; Sun, Hong; Zhou, Gang; Wang, Zhong-Sheng

    2015-04-01

    An electron-deficient group, 2,3-diphenylquinoxaline (DPQ), is incorporated as an auxiliary acceptor into the different positions of the porphyrin (Por) based donor-π bridge-acceptor (D-π-A) dye (FNE57) to construct D-A‧-Por-π-A (FNE58) and D-Por-A‧-π-A (FNE59) configurations. The incorporation of DPQ unit between the donor and porphyrin unit has negligible influence on the absorption property, whereas the DPQ unit located between the porphyrin unit and acceptor significantly increases the absorbance for the Soret band and the valley between the Soret and Q bands. Theoretical calculation reveals that incorporating the DPQ unit adjacent to the acceptor is more advantageous to delocalize the lowest unoccupied molecular orbital and enhance the electronic asymmetry, which facilitates the intramolecular charge transfer. The effect of DPQ unit and its linkage position on the performance of related quasi-solid-state dye-sensitized solar cells (DSSCs) is systematically investigated. The quasi-solid-state DSSC with sensitizer FNE59 displays a power conversion efficiency of 6.02%, which is 23% and 51% higher than those for FNE57 and FNE58 based DSSCs. Our studies facilitate the understanding of the crucial importance of molecular engineering and pave a new path to design novel porphyrin based sensitizers for highly efficient DSSCs.

  11. Continuous positive airway pressure for bronchiolitis in a general paediatric ward; a feasibility study

    PubMed Central

    2014-01-01

    Background Continuous positive airway pressure (CPAP) is commonly used to relieve respiratory distress in infants with bronchiolitis, but has mostly been studied in an intensive care setting. Our prime aim was to evaluate the feasibility of CPAP for infants with bronchiolitis in a general paediatric ward, and secondary to assess capillary PCO2 (cPCO2) levels before and during treatment. Methods From May 1st 2008 to April 30th 2012, infants with bronchiolitis at Stavanger University Hospital were treated with CPAP in a general paediatric ward, but could be referred to an intensive care unit (ICU) when needed, according to in-house guidelines. Levels of cPCO2 were prospectively registered before the start of CPAP and at approximately 4, 12, 24 and 48 hours of treatment as long as CPAP was given. We had a continuous updating program for the nurses and physicians caring for the infants with CPAP. The study was population based. Results 672 infants (3.4%) were hospitalized with bronchiolitis. CPAP was initiated in 53 infants (0.3%; 7.9% of infants with bronchiolitis), and was well tolerated in all but three infants. 46 infants were included in the study, the majority of these (n = 33) were treated in the general ward only. These infants had lower cPCO2 before treatment (8.0; 7.7, 8.6)(median; quartiles) than those treated at the ICU (n = 13) (9.3;8.5, 9.9) (p < 0.001). The level of cPCO2 was significantly reduced after 4 h in both groups; 1.1 kPa (paediatric ward) (p < 0.001) and 1.3 kPa (ICU) (p = 0.002). Two infants on the ICU did not respond to CPAP (increasing cPCO2 and severe apnoe) and were given mechanical ventilation, otherwise no side effects were observed in either group treated with CPAP. Conclusion Treatment with CPAP for infants with bronchiolitis may be feasible in a general paediatric ward, providing sufficient staffing and training, and the possibility of referral to an ICU when needed. PMID:24886569

  12. Imaging and timing performance of 1 cm x 1 cm position-sensitive solid-state photomultiplier

    NASA Astrophysics Data System (ADS)

    Dokhale, P.; Schmall, J.; Stapels, C.; Christian, J.; Cherry, S. R.; Squillante, M. R.; Shah, K.

    2013-02-01

    We have designed and built a large-area 1cm × 1cm position-sensitive solid-state photomultiplier (PS-SSPM) for use in detector design for medical imaging applications. Our new large-area PS-SSPM concept implements resistive network between the micro-pixels, which are photodiodes operated in Geiger mode, called Geiger Photodiodes (GPDs), to provide continuous position sensitivity. Here we present imaging and timing performance of the large-area PS-SSPM for different temperatures and operating biases to find the optimum operating parameters for the device in imaging applications. A detector module was built by coupling a polished 8 × 8 LYSO array, with 1 × 1 × 20 mm3 elements, to a 1 × 1 cm2 PS-SSPM. Flood images recorded at room temperature show good crystal separation as all 64 elements were separated from each other. Cooling the device at 10 °C showed significant improvement. The device optimum bias voltage was ~ 4.5V over breakdown voltage. The coincidence timing resolution was improved significantly by increasing the operating bias, as well as by lowering the temperature to 0 °C. Results show excellent imaging performance and good timing response with a large-area PS-SSPM device.

  13. Continuous and Delayed Photohemolysis Sensitized With Methylene Blue and Iron Oxide Nanoparticles (Fe3O4)

    NASA Astrophysics Data System (ADS)

    AL-Akhras, M.-Ali; Aljarrah, Khaled; Albiss, Borhan; Alhaji Bala, Abba

    2015-10-01

    This research present the sensitization of methylene blue (MB), as a potential photodynamic therapy photo sensitizer which showed phototoxicity for many tumor cells in vitro incorporated with iron oxide nanoparticles (Fe3O4, IO-NP), which offer magnificent interaction both inside and outside the surface of biomolecules together with red blood cells (RBC's) with significant change in hemolysis process. The study investigated the sensitization of continuous photohemolysis (CPH) for MB and MB with IO-NP, delayed photohemolysis (DPH) at different irradiation temperature (Tirr). The photohemolysis rate for CPH at room temperature has a power dependence of 0.39 ± 0.05 with relative of steepness of 1.25 ± 0.02 and for different concentration of MB and power dependent of 0.15 ± 0.03 with relative steepness of 1.34 ± 0.01 for different MB and IO-NP. Logistic and Gompertz functions were applied as appropriate mathematical models to fit the collected experimental data for CPH and DPH respectively, and to calculate fractional photohemolysis rate with minimum errors. The Logistic function parameter; α, the hemolysis rate, increases with increasing concentrations of MB and decreases with increasing IO-NP concentrations in the presence of 6 μg/ml of MB. The parameter β the time required to reduce the maximum number of RBCs to one half of its value, decreases with increasing MB concentration and increases with increasing IO-NP concentrations in the presence of 6 pg/ml of MB. In DPH at different Tirr, the Gompertz parameter; a, fractional hemolysis ratio, is independent of temperature in both case MB and MB plus IO-NP, while the parameter; b, rate of fractional hemolysis change, increases with increasing Tirr, in both case MB and MB plus IO-NP. The apparent activation energy of colloid-osmotic hemolysis is 9.47±0.01 Kcal/mol with relative steepness of 1.31 ± 0.05 for different MB and 6.06±0.03 Kcal/mol with relative steepness of 1.41 ± 0.09 for MB with iron oxide. Our

  14. Development of a simple test device for spindle error measurement using a position sensitive detector

    NASA Astrophysics Data System (ADS)

    Liu, Chien-Hung; Jywe, Wen-Yuh; Lee, Hau-Wei

    2004-09-01

    A new spindle error measurement system has been developed in this paper. It employs a design development rotational fixture with a built-in laser diode and four batteries to replace a precision reference master ball or cylinder used in the traditional method. Two measuring devices with two position sensitive detectors (one is designed for the measurement of the compound X-axis and Y-axis errors and the other is designed with a lens for the measurement of the tilt angular errors) are fixed on the machine table to detect the laser point position from the laser diode in the rotational fixture. When the spindle rotates, the spindle error changes the direction of the laser beam. The laser beam is then divided into two separated beams by a beam splitter. The two separated beams are projected onto the two measuring devices and are detected by two position sensitive detectors, respectively. Thus, the compound motion errors and the tilt angular errors of the spindle can be obtained. Theoretical analysis and experimental tests are presented in this paper to separate the compound errors into two radial errors and tilt angular errors. This system is proposed as a new instrument and method for spindle metrology.

  15. Exploring the spatial resolution of position-sensitive microchannel plate detectors

    NASA Astrophysics Data System (ADS)

    Wiggins, Blake; Siwal, Davinder; Desouza, Romualdo

    2016-03-01

    High amplification and excellent timing make microchannel plate (MCP) detectors excellent devices for detection of photons, electrons, and ions. In addition to providing sub-nanosecond time resolution MCP detectors can also provide spatial resolution, thus making them useful in imaging applications. Use of a resistive anode (RA) is a routinely used approach to make an MCP position-sensitive. The spatial resolution of the RA associated with detection of a single incident electron was determined. Factors impacting the spatial resolution obtained with the RA will be discussed and the achieved spatial resolution of 64 μm (FWHM) will be presented. Recently, a novel approach has been developed to provide position-sensitivity for an MCP detector. In this approach, namely the induced signal approach, the position of the incident particle is determined by sensing the electron cloud emanating from a MCP stack. By utilizing the zero-crossing point of the inherently bipolar signals, a spatial resolution of 466 μm (FWHM) has been achieved. Work to improve the spatial resolution of the induced signal approach further will be presented. Supported by the US DOE NNSA under Award No. DE-NA0002012.

  16. An improved method of energy calibration for position-sensitive silicon detectors

    NASA Astrophysics Data System (ADS)

    Sun, Ming-Dao; Huang, Tian-Heng; Liu, Zhong; Ding, Bing; Yang, Hua-Bin; Zhang, Zhi-Yuan; Wang, Jian-Guo; Ma, Long; Yu, Lin; Wang, Yong-Sheng; Gan, Zai-Guo; Xiao-Hong, Zhou

    2016-04-01

    Energy calibration of resistive charge division-based position-sensitive silicon detectors is achieved by parabolic fitting in the traditional method, where the systematic variations of vertex and curvature of the parabola with energy must be considered. In this paper we extend the traditional method in order to correct the fitting function, simplify the procedure of calibration and improve the experimental data quality. Instead of a parabolic function as used in the traditional method, a new function describing the relation of position and energy is introduced. The energy resolution of the 8.088 MeV α decay of 213Rn is determined to be about 87 keV (FWHM), which is better than the result of the traditional method, 104 keV (FWHM). The improved method can be applied to the energy calibration of resistive charge division-based position-sensitive silicon detectors with various performances. Supported by ‘100 Person Project’ of the Chinese Academy of Sciences and the National Natural Science Foundation of China (11405224 and 11435014)

  17. Biological Basis for Increased Sensitivity to Radiation Therapy in HPV-Positive Head and Neck Cancers

    PubMed Central

    Bol, V.; Grégoire, V.

    2014-01-01

    Although development of head and neck squamous cell carcinomas (HNSCCs) is commonly linked to the consumption of tobacco and alcohol, a link between human papillomavirus (HPV) infection and a subgroup of head and neck cancers has been established. These HPV-positive tumors represent a distinct biological entity with overexpression of viral oncoproteins E6 and E7. It has been shown in several clinical studies that HPV-positive HNSCCs have a more favorable outcome and greater response to radiotherapy. The reason for improved prognosis of HPV-related HNSCC remains speculative, but it could be owned to multiple factors. One hypothesis is that HPV-positive cells are intrinsically more sensitive to standard therapies and thus respond better to treatment. Another possibility is that HPV-positive tumors uniquely express viral proteins that induce an immune response during therapy that helps clear tumors and prevents recurrence. Here, we will review current evidence for the biological basis of increased radiosensitivity in HPV-positive HNSCC. PMID:24804233

  18. Application of continuous positive airway pressure in the delivery room: a multicenter randomized clinical trial

    PubMed Central

    Gonçalves-Ferri, W.A.; Martinez, F.E.; Caldas, J.P.S.; Marba, S.T.M.; Fekete, S.; Rugolo, L.; Tanuri, C.; Leone, C.; Sancho, G.A.; Almeida, M.F.B.; Guinsburg, R.

    2014-01-01

    This study evaluated whether the use of continuous positive airway pressure (CPAP) in the delivery room alters the need for mechanical ventilation and surfactant during the first 5 days of life and modifies the incidence of respiratory morbidity and mortality during the hospital stay. The study was a multicenter randomized clinical trial conducted in five public university hospitals in Brazil, from June 2008 to December 2009. Participants were 197 infants with birth weight of 1000-1500 g and without major birth defects. They were treated according to the guidelines of the American Academy of Pediatrics (APP). Infants not intubated or extubated less than 15 min after birth were randomized for two treatments, routine or CPAP, and were followed until hospital discharge. The routine (n=99) and CPAP (n=98) infants studied presented no statistically significant differences regarding birth characteristics, complications during the prenatal period, the need for mechanical ventilation during the first 5 days of life (19.2 vs 23.4%, P=0.50), use of surfactant (18.2 vs 17.3% P=0.92), or respiratory morbidity and mortality until discharge. The CPAP group required a greater number of doses of surfactant (1.5 vs 1.0, P=0.02). When CPAP was applied to the routine group, it was installed within a median time of 30 min. We found that CPAP applied less than 15 min after birth was not able to reduce the need for ventilator support and was associated with a higher number of doses of surfactant when compared to CPAP applied as clinically indicated within a median time of 30 min. PMID:24554040

  19. High Flow Nasal Cannula as a Method for Rapid Weaning From Nasal Continuous Positive Airway Pressure

    PubMed Central

    Badiee, Zohreh; Eshghi, Alireza; Mohammadizadeh, Majid

    2015-01-01

    Background: To compare two methods of weaning premature infants from nasal continuous positive airway pressure (NCPAP). Methods: Between March and November 2012, 88 preterm infants who were stable on NCPAP of 5 cmH2O with FIO2 <30% for a minimum of 6 h were randomly allocated to one of two groups. The high flow nasal cannula (HFNC) group received HFNC with flow of 2 L/min and FIO2 = 0.3 and then stepwise reduction of FIO2 and then flow. The non-HFNC group was maintained on NCPAP of 5 cmH2O and gradual reduction of oxygen until they were on FIO2 = 0.21 for 6 h, and we had weaned them directly from NCPAP (with pressure of 5 cmH2O) to room air. Results: No significant differences were found between 2 study groups with regards to gestational age, birth weight, Apgar score at 1 and 5 min after birth, patent ductus arteriosus and use of xanthines. The mean duration of oxygen therapy after randomization was significantly lower in HFNC group compared to non-HFNC group (20.6 ± 16.8 h vs. 49.6 ± 25.3 h, P < 0.001). Also, the mean length of hospital stay was significantly lower in HFNC group compared to non-HFNC group (11.3 ± 7.8 days vs. 14.8 ± 8.6 days, P = 0.04). The rate of successful weaning was not statistically different between two groups. Conclusions: Weaning from NCPAP to HFNC could decrease the duration of oxygen therapy and length of hospitalization in preterm infants. PMID:25949783

  20. Continuous positive airway pressure titration in infants with severe upper airway obstruction or bronchopulmonary dysplasia

    PubMed Central

    2013-01-01

    Abstracta Introduction Noninvasive continuous positive airway pressure (CPAP) is recognized as an effective treatment for severe airway obstruction in young children. The aim of the present study was to compare a clinical setting with a physiological setting of noninvasive CPAP in infants with nocturnal alveolar hypoventilation due to severe upper airway obstruction (UAO) or bronchopulmonary dysplasia (BPD). Methods The breathing pattern and respiratory muscle output of all consecutive infants due to start CPAP in our noninvasive ventilation unit were retrospectively analysed. CPAP set on clinical noninvasive parameters (clinical CPAP) was compared to CPAP set on the normalization or the maximal reduction of the oesophageal pressure (Poes) and transdiaphragmatic pressure (Pdi) swings (physiological CPAP). Expiratory gastric pressure (Pgas) swing was measured. Results The data of 12 infants (mean age 10 ± 8 mo) with UAO (n = 7) or BPD (n = 5) were gathered. The mean clinical CPAP (8 ± 2 cmH2O) was associated with a significant decrease in Poes and Pdi swings. Indeed, Poes swing decreased from 31 ± 15 cmH2O during spontaneous breathing to 21 ± 10 cmH2O during CPAP (P < 0.05). The mean physiological CPAP level was 2 ± 2 cmH2O higher than the mean clinical CPAP level and was associated with a significantly greater improvement in all indices of respiratory effort (Poes swing 11 ± 5 cm H2O; P < 0.05 compared to clinical CPAP). Expiratory abdominal activity was present during the clinical CPAP and decreased during physiological CPAP. Conclusions A physiological setting of noninvasive CPAP, based on the recording of Poes and Pgas, is superior to a clinical setting, based on clinical noninvasive parameters. Expiratory abdominal activity was present during spontaneous breathing and decreased in the physiological CPAP setting. PMID:23889768

  1. Use of continuous positive airway pressure reduces airway reactivity in adults with asthma

    PubMed Central

    Busk, Michael; Busk, Nancy; Puntenney, Paula; Hutchins, Janet; Yu, Zhangsheng; Gunst, Susan J.; Tepper, Robert S.

    2015-01-01

    Asthma is characterised by airway hyperreactivity, which is primarily treated with β-adrenergic bronchodilators and anti-inflammatory agents. However, mechanical strain during breathing is an important modulator of airway responsiveness and we have previously demonstrated in animal models that continuous positive airway pressure (CPAP) resulted in lower in vivo airway reactivity. We now evaluated whether using nocturnal CPAP decreased airway reactivity in clinically-stable adults with asthma. Adults with stable asthma and normal spirometry used nocturnal CPAP (8–10 cmH2O) or sham treatment (0–2 cmH2O) for 7 days. Spirometry and bronchial challenges were obtained before and after treatment. The primary outcome was the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20). The CPAP group (n=16) had a significant decrease in airway reactivity (change in (Δ)logPC20 0.406, p<0.0017) while the sham group (n=9) had no significant change in airway reactivity (ΔlogPC20 0.003, p=0.9850). There was a significant difference in the change in airway reactivity for the CPAP versus the sham group (ΔlogPC20 0.41, p<0.043). Our findings indicate that chronic mechanical strain of the lungs produced using nocturnal CPAP for 7 days reduced airway reactivity in clinically stable asthmatics. Future studies of longer duration are required to determine whether CPAP can also decrease asthma symptoms and/or medication usage. PMID:22835615

  2. Conceptual design of elliptical cavities for intensity and position sensitive beam measurements in storage rings

    NASA Astrophysics Data System (ADS)

    Sanjari, M. S.; Chen, X.; Hülsmann, P.; Litvinov, Yu A.; Nolden, F.; Piotrowski, J.; Steck, M.; Stöhlker, Th

    2015-11-01

    Position sensitive beam monitors are indispensable for the beam diagnostics in storage rings. Apart from their applications in the measurements of beam parameters, they can be used in non-destructive in-ring decay studies of radioactive ion beams as well as enhancing precision in the isochronous mass measurement technique. In this work, we introduce a novel approach based on cavities with elliptical cross-section, in order to compensate the limitations of known designs for the application in ion storage rings. The design is aimed primarily for future heavy ion storage rings of the FAIR project. The conceptual design is discussed together with simulation results.

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

    NASA Astrophysics Data System (ADS)

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

    2002-11-01

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

  4. Gamma ray measurement of earth formation properties using a position sensitive scintillation detector

    SciTech Connect

    Sonne, D.S.

    1986-10-21

    This patent describes a system for measuring properties of earth formations in the vicinity of a well borehole at different radial distances from the borehole, comprising: a fluid tight hollow body member sized and adapted for passage through a well borehole and housing therein; a source of gamma rays and means for directing gamma rays from the source outwardly from the body member into earth formations in the vicinity of the borehole; and a position sensitive scintillation detector for detecting gamma rays scattered back into the body member from the earth formation in the vicinity of the borehole and means for collimating the scattered gamma rays onto the detector.

  5. CdZnTe position-sensitive drift detectors with thicknesses up to 5 cm

    NASA Astrophysics Data System (ADS)

    Bolotnikov, A. E.; Camarda, G. S.; Chen, E.; Cheng, S.; Cui, Y.; Gul, R.; Gallagher, R.; Dedic, V.; De Geronimo, G.; Ocampo Giraldo, L.; Fried, J.; Hossain, A.; MacKenzie, J. M.; Sellin, P.; Taherion, S.; Vernon, E.; Yang, G.; El-hanany, U.; James, R. B.

    2016-02-01

    We investigated the feasibility of long-drift-time CdZnTe (CZT) gamma-ray detectors, fabricated from CZT material produced by Redlen Technologies. CZT crystals with cross-section areas of 5 × 5 mm2 and 6 × 6 mm2 and thicknesses of 20-, 30-, 40-, and 50-mm were configured as 3D position-sensitive drift detectors and were read out using a front-end ASIC. By correcting the electron charge losses caused by defects in the crystals, we demonstrated high performance for relatively thick detectors fabricated from unselected CZT material.

  6. Identifying Moderators of the Link Between Parent and Child Anxiety Sensitivity: The Roles of Gender, Positive Parenting, and Corporal Punishment.

    PubMed

    Graham, Rebecca A; Weems, Carl F

    2015-07-01

    A substantial body of literature suggests that anxiety sensitivity is a risk factor for the development of anxiety problems and research has now begun to examine the links between parenting, parent anxiety sensitivity and their child's anxiety sensitivity. However, the extant literature has provided mixed findings as to whether parent anxiety sensitivity is associated with child anxiety sensitivity, with some evidence suggesting that other factors may influence the association. Theoretically, specific parenting behaviors may be important to the development of child anxiety sensitivity and also in understanding the association between parent and child anxiety sensitivity. In this study, 191 families (n = 255 children and adolescents aged 6-17 and their parents) completed measures of child anxiety sensitivity (CASI) and parenting (APQ-C), and parents completed measures of their own anxiety sensitivity (ASI) and their parenting (APQ-P). Corporal punishment was associated with child anxiety sensitivity and the child's report of their parent's positive parenting behaviors moderated the association between parent and child anxiety sensitivity. The child's gender was also found to moderate the association between parent and child anxiety sensitivity, such that there was a positive association between girls' and their parents anxiety sensitivity and a negative association in boys. The findings advance the understanding of child anxiety sensitivity by establishing a link with corporal punishment and by showing that the association between parent and child anxiety sensitivity may depend upon the parenting context and child's gender. PMID:25301177

  7. Identifying Moderators of the Link between Parent and Child Anxiety Sensitivity: The Roles of Gender, Positive Parenting, and Corporal Punishment

    PubMed Central

    Graham, Rebecca A.; Weems, Carl F.

    2014-01-01

    A substantial body of literature suggests that anxiety sensitivity is a risk factor for the development of anxiety problems and research has now begun to examine the links between parenting, parent anxiety sensitivity and their child’s anxiety sensitivity. However, the extant literature has provided mixed findings as to whether parent anxiety sensitivity is associated with child anxiety sensitivity, with some evidence suggesting that others factors may influence the association. Theoretically, specific parenting behaviors may be important to the development of child anxiety sensitivity and also in understanding the association between parent and child anxiety sensitivity. In this study, 191 families (n = 255 children and adolescents aged 6–17 and their parents) completed measures of child anxiety sensitivity (CASI) and parenting (APQ-C), and parents completed measures of their own anxiety sensitivity (ASI) and their parenting (APQ-P). Corporal punishment was associated with child anxiety sensitivity and the child’s report of their parent’s positive parenting behaviors moderated the association between parent and child anxiety sensitivity. The child’s gender was also found to moderate the association between parent and child anxiety sensitivity, such that there was a positive association between girls and parent anxiety sensitivity and a negative association in boys. The findings advance the understanding of child anxiety sensitivity by establishing a link with corporal punishment and by showing that the association between parent and child anxiety sensitivity may depend upon the parenting context and child’s gender. PMID:25301177

  8. Time and position sensitive single photon detector for scintillator read-out

    NASA Astrophysics Data System (ADS)

    Schössler, S.; Bromberger, B.; Brandis, M.; Schmidt, L. Ph H.; Tittelmeier, K.; Czasch, A.; Dangendorf, V.; Jagutzki, O.

    2012-02-01

    We have developed a photon counting detector system for combined neutron and γ radiography which can determine position, time and intensity of a secondary photon flash created by a high-energy particle or photon within a scintillator screen. The system is based on a micro-channel plate photomultiplier concept utilizing image charge coupling to a position- and time-sensitive read-out anode placed outside the vacuum tube in air, aided by a standard photomultiplier and very fast pulse-height analyzing electronics. Due to the low dead time of all system components it can cope with the high throughput demands of a proposed combined fast neutron and dual discrete energy γ radiography method (FNDDER). We show tests with different types of delay-line read-out anodes and present a novel pulse-height-to-time converter circuit with its potential to discriminate γ energies for the projected FNDDER devices for an automated cargo container inspection system (ACCIS).

  9. A diagnostic for micrometer sensitive positioning of solid targets in intense laser-matter interaction

    NASA Astrophysics Data System (ADS)

    Singh, Prashant Kumar; Kakolee, K. F.; Jeong, T. W.; Ter-Avetisyan, Sargis

    2016-09-01

    A target position monitoring diagnostic, relevant to intense laser-solid interaction, is presented. The alignment system, having a sensitivity of few micrometers, consist of an infinity corrected long working distance objective, a broadband illuminating source and a CCD camera. The imaging system, placed along the axis of incident laser pulse, serves the dual purpose of laser focus diagnosis and precise positioning of the target in three dimension axis. By employing this technique, solid targets with thickness varying from opaque micrometer thick foils to few nanometer thin transparent foils can be aligned precisely. The effectiveness of the entire alignment system is demonstrated in enhanced acceleration of ions in intense laser-matter interaction, with very high reproducibility.

  10. Read-out of scintillating fibres using a weak cross-talk position-sensitive photomultiplier

    NASA Astrophysics Data System (ADS)

    Agoritsas, V.; Akchurin, N.; Bing, O.; Bravar, A.; Drevenak, R.; Finger, Mic.; Finger, Mir.; Flaminio, V.; Digirolamo, B.; Gorin, A.; Kuroda, K.; Manuilov, I.; Okada, K.; Onel, Y.; Penzo, A.; Rappazzo, G. F.; Riazantsev, A.; Slunecka, M.; Takeutchi, F.; Yoshida, T.

    1998-02-01

    Fast and precise readout of scintillating fibres (SciFi) has a great potential for fast tracking and triggering at high-luminosity particle physics experiments. In the framework of the RD-17 experiment at CERN (FAROS) significant milestones in the development of SciFi detectors using position-sensitive photomultipliers have been achieved. Results obtained with a weak cross-talk multi-anode photomultiplier, Philips XP1724, and a parallel readout of the anodes are reported. With 0.5 mm diameter fibres a spatial resolution of about 125 μm and a detection efficiency in excess of 95% have been obtained. The time dispersion of signals from individual photomultiplier channels has been estimated to be about 1 ns. The possibility of digitising the track position in real time by a peak-sensing circuit is studied for the first time

  11. Demonstration of a high sensitivity GNSS software receiver for indoor positioning

    NASA Astrophysics Data System (ADS)

    Lin, Tao; Ma, Martin; Broumandan, Ali; Lachapelle, Gérard

    2013-03-01

    Advances in signal processing techniques contributed to the significant improvements of GNSS receiver performance in dense multipath environments and created the opportunities for a new category of high-sensitivity GNSS (HS-GNSS) receivers that can provide GNSS location services in indoor environments. The difficulties in improving the availability, reliability, and accuracy of these indoor capable GNSS receivers exceed those of the receivers designed for the most hostile urban canyon environments. The authors of this paper identified the vector tracking schemes, signal propagation statistics, and parallel processing techniques that are critical to a robust HS-GNSS receiver for indoor environments and successfully incorporated them into a fully functional high-sensitivity software receiver. A flexible vector-based receiver architecture is introduced to combine these key indoor signal processing technologies into GSNRx-hs™ - the high sensitivity software navigation receiver developed at the University of Calgary. The resulting receiver can perform multi-mode vector tracking in indoor environment at various levels of location and timing uncertainties. In addition to the obvious improvements in time-to-first-fix (TTFF) and signal sensitivity, the field test results in indoor environments surrounded by wood, glass, and concrete showed that the new techniques effectively improved the performance of indoor GNSS positioning. With fine GNSS timing, the proposed receiver can consistently deliver indoor navigation solution with the horizontal accuracy of 2-15 m depending on the satellite geometry and the indoor environments. If only the coarse GNSS timing is available, the horizontal accuracy of the indoor navigation solution from the proposed receiver is around 30 m depending on the coarse timing accuracy, the satellite geometry, and the indoor environments. From the preliminary field test results, it has been observed that the signal processing sensitivity is the

  12. Antibiotic sensitivity pattern in blaNDM-1-positive and carbapenemase-producing Enterobacteriaceae

    PubMed Central

    Mulla, Summaiya; Charan, Jaykaran; Rajdev, Sangita

    2016-01-01

    Background: Some studies published in recent time revealed that many bacteria from Enterobacteriaceae group are multi-antibiotic-resistant because of the production enzymes carbapenemase particularly New Delhi metallo-beta-lactamase encoded by gene called blaNDM-1. Looking at public health importance of this issue there is a need for studies at other centers to confirm or refute published findings. Objectives: This study was designed with the aim of exploring antibiotic resistance in Enterobacteriaceae group of bacteria and also to explore gene and enzyme responsible for it. Materials and Methods: Samples of Enterobacteriaceae were collected from wards and outpatient departments. Antibiotic sensitivity was checked by an automated system (VITEK 2 COMPACT). Carbapenemase production was assessed by Modified Hodge Test. Presence of blaNDM-1 was assessed by polymerase chain reaction. Statistics: Frequency and percentage were used to describe the data. Frequency of sensitivity was compared between carbapenemase producers and noncarbapenemase producers by Fisher's exact test. Results: Forty-seven percent bacteria were found to be producing carbapenemase enzyme. These bacteria were significantly less sensitive to cefoperazone, cefepime, and amikacin. Among carbapenemase-producing organisms, 3% and 6% were resistant to tigecycline and colistin, respectively. Forty percent bacteria were found to be having blaNDM-1 gene. There was a significant difference between blaNDM-1-positive and blaNDM-1-negative for sensitivity toward cefoperazone + sulbactam, imipenem, meropenem, amikacin, tobramycine, ciprofloxacin, and levofloxacin. Conclusion: Presence of carbapenemase enzyme and blaNDM-1 gene is associated with high level of resistance in Enterobacteriaceae group of bacteria and only few antibiotics have good sensitivity for these organisms. PMID:26958516

  13. Sensitivity analysis of a cemented hip stem to implant position and cement mantle thickness.

    PubMed

    Shi, J; Browne, M; Strickland, M; Flivik, G; Taylor, M

    2014-11-01

    Patient-specific finite element models of the implanted proximal femur can be built from pre-operative computed tomography scans and post-operative X-rays. However, estimating three-dimensional positioning from two-dimensional radiographs introduces uncertainty in the implant position. Further, accurately measuring the thin cement mantle and the degree of cement-bone interdigitation from imaging data is challenging. To quantify the effect of these uncertainties in stem position and cement thickness, a sensitivity study was performed. A design-of-experiment study was implemented, simulating both gait and stair ascent. Cement mantle stresses and bone-implant interface strains were monitored. The results show that small variations in alignment affect the implant biomechanics, especially around the most proximal and most distal ends of the stem. The results suggest that implant position is more influential than cement thickness. Rotation around the medial-lateral axis is the dominant factor in the proximal zones and stem translations are the dominant factors around the distal tip. PMID:23405986

  14. Effect of Nasal Obstruction on Continuous Positive Airway Pressure Treatment: Computational Fluid Dynamics Analyses

    PubMed Central

    Wakayama, Tadashi; Suzuki, Masaaki; Tanuma, Tadashi

    2016-01-01

    Objective Nasal obstruction is a common problem in continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea and limits treatment compliance. The purpose of this study is to model the effects of nasal obstruction on airflow parameters under CPAP using computational fluid dynamics (CFD), and to clarify quantitatively the relation between airflow velocity and pressure loss coefficient in subjects with and without nasal obstruction. Methods We conducted an observational cross-sectional study of 16 Japanese adult subjects, of whom 9 had nasal obstruction and 7 did not (control group). Three-dimensional reconstructed models of the nasal cavity and nasopharynx with a CPAP mask fitted to the nostrils were created from each subject’s CT scans. The digital models were meshed with tetrahedral cells and stereolithography formats were created. CPAP airflow simulations were conducted using CFD software. Airflow streamlines and velocity contours in the nasal cavities and nasopharynx were compared between groups. Simulation models were confirmed to agree with actual measurements of nasal flow rate and with pressure and flow rate in the CPAP machine. Results Under 10 cmH2O CPAP, average maximum airflow velocity during inspiration was 17.6 ± 5.6 m/s in the nasal obstruction group but only 11.8 ± 1.4 m/s in the control group. The average pressure drop in the nasopharynx relative to inlet static pressure was 2.44 ± 1.41 cmH2O in the nasal obstruction group but only 1.17 ± 0.29 cmH2O in the control group. The nasal obstruction and control groups were clearly separated by a velocity threshold of 13.5 m/s, and pressure loss coefficient threshold of approximately 10.0. In contrast, there was no significant difference in expiratory pressure in the nasopharynx between the groups. Conclusion This is the first CFD analysis of the effect of nasal obstruction on CPAP treatment. A strong correlation between the inspiratory pressure loss coefficient and maximum airflow

  15. Cost-effectiveness of Out-of-Hospital Continuous Positive Airway Pressure for Acute Respiratory Failure

    PubMed Central

    Thokala, Praveen; Goodacre, Steve; Ward, Matt; Penn-Ashman, Jerry; Perkins, Gavin D.

    2015-01-01

    Study objective We determine the cost-effectiveness of out-of-hospital continuous positive airway pressure (CPAP) compared with standard care for adults presenting to emergency medical services with acute respiratory failure. Methods We developed an economic model using a United Kingdom health care system perspective to compare the costs and health outcomes of out-of-hospital CPAP to standard care (inhospital noninvasive ventilation) when applied to a hypothetical cohort of patients with acute respiratory failure. The model assigned each patient a probability of intubation or death, depending on the patient’s characteristics and whether he or she had out-of-hospital CPAP or standard care. The patients who survived accrued lifetime quality-adjusted life-years (QALYs) and health care costs according to their age and sex. Costs were accrued through intervention and hospital treatment costs, which depended on patient outcomes. All results were converted into US dollars, using the Organisation for Economic Co-operation and Development purchasing power parities rates. Results Out-of-hospital CPAP was more effective than standard care but was also more expensive, with an incremental cost-effectiveness ratio of £20,514 per QALY ($29,720/QALY) and a 49.5% probability of being cost-effective at the £20,000 per QALY ($29,000/QALY) threshold. The probability of out-of-hospital CPAP’s being cost-effective at the £20,000 per QALY ($29,000/QALY) threshold depended on the incidence of eligible patients and varied from 35.4% when a low estimate of incidence was used to 93.8% with a high estimate. Variation in the incidence of eligible patients also had a marked influence on the expected value of sample information for a future randomized trial. Conclusion The cost-effectiveness of out-of-hospital CPAP is uncertain. The incidence of patients eligible for out-of-hospital CPAP appears to be the key determinant of cost-effectiveness. PMID:25737210

  16. High spatial resolution two-dimensional position sensitive detector for the performance of coincidence experiments

    SciTech Connect

    Ceolin, D.; Chaplier, G.; Lemonnier, M.; Garcia, G.A.; Miron, C.; Nahon, L.; Simon, M.; Leclercq, N.; Morin, P.

    2005-04-01

    A position sensitive detector (PSD) adapted to the technical and mechanical specifications of our angle and energy resolved electron-ion(s) coincidence experiments is described in this article. The device, whose principle is very similar to the one detailed by J. H. D. Eland [Meas. Sci. Technol. 5, 1501 (1994)], is composed by a set of microchannel plates and a delay line anode. The originality comes from the addition in front of the encoding surface of a ceramic disk covered by a resistive surface. The capacitive coupling between the anode and the resistive plane has the double advantage of eliminating the spatial modulations due to the lattice of the anode and also of sensitizing a greater number of electrodes, increasing thus considerably the accuracy of the position measurements. The tests carried out with a time to digital conversion module of 250 ps resolution showed that a spatial resolution better than 50 {mu}m and a dead time of 160 ns can be achieved. Typical images obtained with the help of the EPICEA and DELICIOUS coincidence setups are also shown.

  17. Characterization of contamination through the use of position sensitive detectors and digital image processing

    SciTech Connect

    Shonka, J.J.; DeBord, D.M.; Bennett, T.E.; Weismann, J.J.

    1996-06-01

    This report describes development of a significant new method for monitoring radioactive surface contamination. A floor monitor prototype has been designed which uses position sensitive proportional counter based radiation detectors. The system includes a novel operator interface consisting of an enhanced reality display providing the operator with 3 dimensional contours of contamination and background subtracted stereo clicks. The process software saves electronic files of survey data at very high rates along with time stamped video recording and provides completely documented surveys in a visualization oriented data management system. The data management system allows simple re-assembly of strips of data that are taken with a linear PSPC and allows visualization and treatment of the data using algorithms developed for processing images from earth resource satellites. This report includes a brief history of the development path for the floor monitor, a discussion of position sensitive proportional counter technology, and details concerning the process software, post processor and hardware. The last chapter discusses the field tests that were conducted at five sites and an application of the data management system for data not associated with detector systems.

  18. A position-sensitive twin ionization chamber for fission fragment and prompt neutron correlation experiments

    NASA Astrophysics Data System (ADS)

    Göök, A.; Geerts, W.; Hambsch, F.-J.; Oberstedt, S.; Vidali, M.; Zeynalov, Sh.

    2016-09-01

    A twin position-sensitive Frisch grid ionization chamber, intended as a fission fragment detector in experiments to study prompt fission neutron correlations with fission fragment properties, is presented. Fission fragment mass and energies are determined by means of the double kinetic energy technique, based on conservation of mass and linear momentum. The position sensitivity is achieved by replacing each anode plate in the standard twin ionization chamber by a wire plane and a strip anode, both readout by means of resistive charge division. This provides information about the fission axis orientation, which is necessary to reconstruct the neutron emission process in the fully accelerated fragment rest-frame. The energy resolution compared to the standard twin ionization chamber is found not to be affected by the modification. The angular resolution of the detector relative to an arbitrarily oriented axis is better than 7° FWHM. Results on prompt fission neutron angular distributions in 235U(n,f) obtained with the detector in combination with an array of neutron scintillation detectors is presented as a proof of principle.

  19. Learning from Public Television and the Web: Positioning Continuing Education as a Knowledge Portal.

    ERIC Educational Resources Information Center

    Vedro, Steven R.

    1999-01-01

    Digital convergence--the merging of television and computing--challenges localized monopolies of public television and continuing education. Continuing educators can reposition themselves in the electronic marketplace by serving as an educational portal, bringing their strengths of "brand recognition," local customer base, and access to…

  20. A fast neuronal signal-sensitive continuous-wave near-infrared imaging system.

    PubMed

    Zhang, Zhongxing; Sun, Bailei; Gong, Hui; Zhang, Lei; Sun, Jinyan; Wang, Bangde; Luo, Qingming

    2012-09-01

    We have developed a continuous-wave near-infrared imaging system to measure fast neuronal signals. We used a simultaneous sampling method with a separate high-speed analog-to-digital converter for each input channel, which provides a much larger point sample in a digital lock-in algorithm, higher temporal resolution, and lower crosstalk among detected channels. Without any analog filter, digital lock-in detection with a large point sample suppresses noise excellently, making the system less complex and offering better flexibility. In addition, using a custom-made collimator, more photons can reach the brain tissue due to the smaller divergence angle. Performance analysis shows high detection sensitivity (on the order of 0.1 pW) and high temporal resolution (~50 Hz, 48 channels). Simulation experiments show that intensity changes on the order of 0.01% can be resolved by our instrument when averaging over approximately 500 stimuli. In vivo experiments over the motor cortex show that our instrument can detect fast neuronal signals in the human brain. PMID:23020395

  1. Line-robust statistics for continuous gravitational waves: safety in the case of unequal detector sensitivities

    NASA Astrophysics Data System (ADS)

    Keitel, David; Prix, Reinhard

    2015-02-01

    The multi-detector F-statistic is close to optimal for detecting continuous gravitational waves (CWs) in Gaussian noise. However, it is susceptible to false alarms from instrumental artefacts, for example quasi-monochromatic disturbances (‘lines’), which resemble a CW signal more than Gaussian noise. In a recent paper (Keitel et al 2014 Phys. Rev. D 89 064023), a Bayesian model selection approach was used to derive line-robust detection statistics for CW signals, generalizing both the F-statistic and the F-statistic consistency veto technique and yielding improved performance in line-affected data. Here we investigate a generalization of the assumptions made in that paper: if a CW analysis uses data from two or more detectors with very different sensitivities, the line-robust statistics could be less effective. We investigate the boundaries within which they are still safe to use, in comparison with the F-statistic. Tests using synthetic draws show that the optimally-tuned version of the original line-robust statistic remains safe in most cases of practical interest. We also explore a simple idea on further improving the detection power and safety of these statistics, which we, however, find to be of limited practical use.

  2. A fast neuronal signal-sensitive continuous-wave near-infrared imaging system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongxing; Sun, Bailei; Gong, Hui; Zhang, Lei; Sun, Jinyan; Wang, Bangde; Luo, Qingming

    2012-09-01

    We have developed a continuous-wave near-infrared imaging system to measure fast neuronal signals. We used a simultaneous sampling method with a separate high-speed analog-to-digital converter for each input channel, which provides a much larger point sample in a digital lock-in algorithm, higher temporal resolution, and lower crosstalk among detected channels. Without any analog filter, digital lock-in detection with a large point sample suppresses noise excellently, making the system less complex and offering better flexibility. In addition, using a custom-made collimator, more photons can reach the brain tissue due to the smaller divergence angle. Performance analysis shows high detection sensitivity (on the order of 0.1 pW) and high temporal resolution (˜50 Hz, 48 channels). Simulation experiments show that intensity changes on the order of 0.01% can be resolved by our instrument when averaging over approximately 500 stimuli. In vivo experiments over the motor cortex show that our instrument can detect fast neuronal signals in the human brain.

  3. On the proper treatment of grid sensitivities in continuous adjoint methods for shape optimization

    NASA Astrophysics Data System (ADS)

    Kavvadias, I. S.; Papoutsis-Kiachagias, E. M.; Giannakoglou, K. C.

    2015-11-01

    The continuous adjoint method for shape optimization problems, in flows governed by the Navier-Stokes equations, can be formulated in two different ways, each of which leads to a different expression for the sensitivity derivatives of the objective function with respect to the control variables. The first formulation leads to an expression including only boundary integrals; it, thus, has low computational cost but, when used with coarse grids, its accuracy becomes questionable. The second formulation comprises a sum of boundary and field integrals; due to the field integrals, it has noticeably higher computational cost, obtaining though higher accuracy. In this paper, the equivalence of the two formulations is revisited from the mathematical and, particularly, the numerical point of view. Internal and external aerodynamics cases, in which the objective function is either the total pressure losses or the force exerted on a solid body, are examined and differences in the computed gradients are discussed. After identifying the reason behind these discrepancies, the adjoint formulation is enhanced by the adjoint to a (hypothetical) grid displacement model and the new approach is proved to reproduce the accuracy of the second adjoint formulation while maintaining the low cost of the first one.

  4. Continuous monitoring of cholesterol oleate hydrolysis by hormone-sensitive lipase and other cholesterol esterases.

    PubMed

    Ali, Yassine Ben; Carrière, Frédéric; Verger, Robert; Petry, Stefan; Muller, Günter; Abousalham, Abdelkarim

    2005-05-01

    Hormone-sensitive lipase (HSL) contributes importantly to the hydrolysis of cholesteryl ester in steroidogenic tissues, releasing the cholesterol required for adrenal steroidogenesis. HSL has broad substrate specificity, because it hydrolyzes triacylglycerols (TAGs), diacylglycerols, monoacylglycerols, and cholesteryl esters. In this study, we developed a specific cholesterol esterase assay using cholesterol oleate (CO) dispersed in phosphatidylcholine and gum arabic by sonication. To continuously monitor the hydrolysis of CO by HSL, we used the pH-stat technique. For the sake of comparison, the hydrolysis of CO dispersion was also tested using other cholesteryl ester-hydrolyzing enzymes. The specific activities measured on CO were found to be 18, 100, 27, and 3 micromol/min/mg for HSL, cholesterol esterase from Pseudomonas species, Candida rugosa lipase-3, and cholesterol esterase from bovine pancreas, respectively. The activity of HSL on CO is approximately 4- to 5-fold higher than on long-chain TAGs. In contrast, with all other enzymes tested, the rates of TAG hydrolysis were higher than those of CO hydrolysis. The relatively higher turnover of HSL on CO observed in vitro adds further molecular insight on the physiological importance of HSL in cholesteryl ester catabolism in vivo. Thus, HSL could be considered more as a cholesteryl ester hydrolase than as a TAG lipase. PMID:15716583

  5. Estimated SLR station position and network frame sensitivity to time-varying gravity

    NASA Astrophysics Data System (ADS)

    Zelensky, Nikita P.; Lemoine, Frank G.; Chinn, Douglas S.; Melachroinos, Stavros; Beckley, Brian D.; Beall, Jennifer Wiser; Bordyugov, Oleg

    2014-06-01

    This paper evaluates the sensitivity of ITRF2008-based satellite laser ranging (SLR) station positions estimated weekly using LAGEOS-1/2 data from 1993 to 2012 to non-tidal time-varying gravity (TVG). Two primary methods for modeling TVG from degree-2 are employed. The operational approach applies an annual GRACE-derived field, and IERS recommended linear rates for five coefficients. The experimental approach uses low-order/degree coefficients estimated weekly from SLR and DORIS processing of up to 11 satellites (tvg4x4). This study shows that the LAGEOS-1/2 orbits and the weekly station solutions are sensitive to more detailed modeling of TVG than prescribed in the current IERS standards. Over 1993-2012 tvg4x4 improves SLR residuals by 18 % and shows 10 % RMS improvement in station stability. Tests suggest that the improved stability of the tvg4x4 POD solution frame may help clarify geophysical signals present in the estimated station position time series. The signals include linear and seasonal station motion, and motion of the TRF origin, particularly in Z. The effect on both POD and the station solutions becomes increasingly evident starting in 2006. Over 2008-2012, the tvg4x4 series improves SLR residuals by 29 %. Use of the GRGS RL02 series shows similar improvement in POD. Using tvg4x4, secular changes in the TRF origin Z component double over the last decade and although not conclusive, it is consistent with increased geocenter rate expected due to continental ice melt. The test results indicate that accurate modeling of TVG is necessary for improvement of station position estimation using SLR data.

  6. Daytime sleepiness, cognitive performance and mood after continuous positive airway pressure for the sleep apnoea/hypopnoea syndrome.

    PubMed Central

    Engleman, H. M.; Cheshire, K. E.; Deary, I. J.; Douglas, N. J.

    1993-01-01

    BACKGROUND--Patients with the sleep apnoea/hypopnoea syndrome often receive continuous positive airway pressure to improve their symptoms and daytime performance, yet objective evidence of the effect of this treatment on cognitive performance is lacking. METHODS--A prospective parallel group study was performed comparing the change in objective daytime sleepiness as assessed by multiple sleep latency, cognitive function, and mood in 21 patients (mean (SE) number of apnoeas and hypopnoeas/hour 57 (6)) who received continuous positive airway pressure for three months and 16 patients (49(6) apnoeas and hypopnoeas/hour) who received conservative treatment for a similar period. RESULTS--Both groups showed significant within group changes in cognitive function between baseline and three months, but when comparisons were made between groups the only significant difference was a greater improvement in multiple sleep latency with continuous positive airway pressure. However, the improvement in sleep latency with continuous positive airway pressure was relatively small (3.5 (0.5) to 5.6 (0.7) min). The group treated with continuous positive airway pressure was divided into those who complied well with treatment (> 4.5 hours/night) and those who did not. Those who complied well (n = 14) showed significant improvement in mean sleep latency and also in depression score compared with the controls but no greater improvement in cognitive function. CONCLUSION--This study confirms significant improvements in objective sleepiness and mood with continuous positive airway pressure, but shows no evidence of major improvements in cognitive function. PMID:8236074

  7. Evidence for the sensitivity of a Great Basin terminal lake to storm track position

    NASA Astrophysics Data System (ADS)

    Hatchett, B.; Boyle, D. P.; Garner, C.; Kaplan, M. L.; Bassett, S.

    2014-12-01

    Arid, closed basin watersheds can serve as indicators of regional climate change. In this work we test the hypothesis that surface elevations of Walker Lake, a Great Basin terminal lake, are sensitive to storm track positions. To do so, we use historical climate records, numerically dated paleolakeshore elevations, global reanalysis products and a semi-distributed water balance model. Precipitation and temperature values from calculated wet and dry periods between 1920-2011 were used as input to the model. Storm track climatologies were developed using reanalysis products. Our results demonstrate that a strong relationship exists between historic wet and dry periods and storm track positions. Under the assumption of a stationary climate using these historic wet and dry climates with the model, we simulated lake levels that are consistent with recorded high and lowstands occurring during Heinrich Stadial 1, the Younger Dryas, the Medieval Climate Anomaly and the Little Ice Age. These findings provide direct support for the storm track migration hypothesis. The nonlinear relationship between changes in precipitation and runoff appears to play a critical role in determining why terminal lakes are particularly responsive to changes in storm track positions.

  8. Lipid-conjugated telomerase template antagonists sensitize resistant HER2-positive breast cancer cells to trastuzumab.

    PubMed

    Goldblatt, Erin M; Erickson, Priscilla A; Gentry, Erin R; Gryaznov, Sergei M; Herbert, Brittney-Shea

    2009-11-01

    HER2 amplification in breast cancer is associated with a more aggressive disease, greater likelihood of recurrence, and decreased survival compared to women with HER2-negative breast cancer. Trastuzumab is a monoclonal antibody that inhibits HER2 activity, making this compound an important therapeutic option for patients with HER2-positive breast cancer. However, resistance to trastuzumab develops rapidly in a large number of breast cancer patients. The objective of this study was to determine whether GRN163L, a telomerase template antagonist currently in clinical trials for cancer treatment, can augment the effects of trastuzumab in breast cancer cells with HER2 amplification. GRN163L was effective in inhibiting telomerase activity and shortening telomeres in HER2-positive breast cancer cells. We show that GRN163L acts synergistically with trastuzumab in inhibiting HER2-positive breast cancer cell growth. More importantly, we show that GRN163L can restore the sensitivity of therapeutic-resistant breast cancer cells to trastuzumab. These findings implicate that telomerase template antagonists have potential use in the treatment of cancers that have developed resistance to traditional cancer therapy. PMID:18853252

  9. Development of Position-Sensitive Magnetic Calorimeter X-ray Detectors

    NASA Astrophysics Data System (ADS)

    Porst, Jan-Patrick; Bandler, Simon R.; Adams, Joseph S.; Hsieh, Wen-Ting; Rotzinger, Hannes; Seidel, George M.; Smith, Stephen J.; Stevenson, Thomas R.

    2009-12-01

    We are developing arrays of position-sensitive magnetic calorimeter (PoSM) X-ray detectors for future astronomy missions. The PoSM consists of multiple absorbers thermally coupled to one magnetic sensor. Each absorber element has a different thermal coupling to the sensor. This results in a distribution of different pulse shapes and enables position discrimination between the absorber elements. PoSMs are motivated by the desire to achieve the largest possible focal plane area with the fewest number of readout channels without compromising on spatial sampling. Optimizing the performance of PoSMs requires careful design of key parameters such as the thermal conductances between the absorbers, magnetic sensor and the heat sink, as well as the absorber heat capacities. We report on the first experimental results from four-absorber PoSMs, each absorber consisting of a two layer composite of bismuth and gold. The measured energy resolution (FWHM) was less than 5 eV for 6 keV X-rays into all four absorbers. Straightforward position discrimination by means of rise-time is also demonstrated.

  10. Development of Position-Sensitive Magnetic Calorimeter X-ray Detectors

    SciTech Connect

    Porst, Jan-Patrick; Bandler, Simon R.; Adams, Joseph S.; Smith, Stephen J.; Hsieh, W.-T.; Stevenson, Thomas R.; Rotzinger, Hannes; Seidel, George M.

    2009-12-16

    We are developing arrays of position-sensitive magnetic calorimeter (PoSM) X-ray detectors for future astronomy missions. The PoSM consists of multiple absorbers thermally coupled to one magnetic sensor. Each absorber element has a different thermal coupling to the sensor. This results in a distribution of different pulse shapes and enables position discrimination between the absorber elements. PoSMs are motivated by the desire to achieve the largest possible focal plane area with the fewest number of readout channels without compromising on spatial sampling. Optimizing the performance of PoSMs requires careful design of key parameters such as the thermal conductances between the absorbers, magnetic sensor and the heat sink, as well as the absorber heat capacities. We report on the first experimental results from four-absorber PoSMs, each absorber consisting of a two layer composite of bismuth and gold. The measured energy resolution (FWHM) was less than 5 eV for 6 keV X-rays into all four absorbers. Straightforward position discrimination by means of rise-time is also demonstrated.

  11. Polyanions decelerate the kinetics of positively charged gramicidin channels as shown by sensitized photoinactivation.

    PubMed Central

    Antonenko, Yuri N; Borisenko, Vitali; Melik-Nubarov, Nikolay S; Kotova, Elena A; Woolley, G Andrew

    2002-01-01

    The effects of different anionic polymers on the kinetic properties of ionic channels formed by neutral gramicidin A (gA) and its positively charged analogs gramicidin-tris(2-aminoethyl)amine (gram-TAEA) and gramicidin-ethylenediamine (gram-EDA) in a bilayer lipid membrane were studied using a method of sensitized photoinactivation. The addition of Konig's polyanion caused substantial deceleration of the photoinactivation kinetics of gram-TAEA channels, which expose three positive charges to the aqueous phase at both sides of the membrane. In contrast, channels formed of gram-EDA, which exposes one positive charge, and neutral gA channels were insensitive to Konig's polyanion. The effect strongly depended on the nature of the polyanion added, namely: DNA, RNA, polyacrylic acid, and polyglutamic acid were inactive, whereas modified polyacrylic acid induced deceleration of the channel kinetics at high concentrations. In addition, DNA was able to prevent the action of Konig's polyanion. In single-channel experiments, the addition of Konig's polyanion resulted in the appearance of long-lived gram-TAEA channels. The deceleration of the gram-TAEA channel kinetics was ascribed to electrostatic interaction of the polyanion with gram-TAEA that reduces the mobility of gram-TAEA monomers and dimers in the membrane via clustering of channels. PMID:11867447

  12. Micro Cantilever Movement Detection with an Amorphous Silicon Array of Position Sensitive Detectors

    PubMed Central

    Contreras, Javier; Costa, Daniel; Pereira, Sonia; Fortunato, Elvira; Martins, Rodrigo; Wierzbicki, Rafal; Heerlein, Holger; Ferreira, Isabel

    2010-01-01

    The movement of a micro cantilever was detected via a self constructed portable data acquisition prototype system which integrates a linear array of 32 1D amorphous silicon position sensitive detectors (PSD). The system was mounted on a microscope using a metal structure platform and the movement of the 30 μm wide by 400 μm long cantilever was tracked by analyzing the signals acquired by the 32 sensor array electronic readout system and the relevant data algorithm. The obtained results show a linear behavior of the photocurrent relating X and Y movement, with a non-linearity of about 3%, a spatial resolution of less than 2 μm along the lateral dimension of the sensor as well as of less than 3 μm along the perpendicular dimension of the sensor, when detecting just the micro-cantilever, and a spatial resolution of less than 1 μm when detecting the holding structure. PMID:22163648

  13. Measuring relative-story displacement and local inclination angle using multiple position-sensitive detectors.

    PubMed

    Matsuya, Iwao; Katamura, Ryuta; Sato, Maya; Iba, Miroku; Kondo, Hideaki; Kanekawa, Kiyoshi; Takahashi, Motoichi; Hatada, Tomohiko; Nitta, Yoshihiro; Tanii, Takashi; Shoji, Shuichi; Nishitani, Akira; Ohdomari, Iwao

    2010-01-01

    We propose a novel sensor system for monitoring the structural health of a building. The system optically measures the relative-story displacement during earthquakes for detecting any deformations of building elements. The sensor unit is composed of three position sensitive detectors (PSDs) and lenses capable of measuring the relative-story displacement precisely, even if the PSD unit was inclined in response to the seismic vibration. For verification, laboratory tests were carried out using an Xθ-stage and a shaking table. The static experiment verified that the sensor could measure the local inclination angle as well as the lateral displacement. The dynamic experiment revealed that the accuracy of the sensor was 150 μm in the relative-displacement measurement and 100 μrad in the inclination angle measurement. These results indicate that the proposed sensor system has sufficient accuracy for the measurement of relative-story displacement in response to the seismic vibration. PMID:22163434

  14. Intensity-sensitive and position-resolving cavity for heavy-ion storage rings

    NASA Astrophysics Data System (ADS)

    Chen, X.; Sanjari, M. S.; Hülsmann, P.; Litvinov, Yu. A.; Nolden, F.; Piotrowski, J.; Steck, M.; Stöhlker, Th.; Walker, P. M.

    2016-08-01

    A heavy-ion storage ring can be adapted for use as an isochronous mass spectrometer if the ion velocity matches the transition energy of the ring. Due to the variety of stored ion species, the isochronous condition cannot be fulfilled for all the ions. In order to eliminate the measurement uncertainty stemming from the velocity spread, an intensity-sensitive and position-resolving cavity is proposed. In this paper we first briefly discuss the correction method for the anisochronism effect in the measurement with the cavity. Then we introduce a novel design, which is operated in the monopole mode and offset from the central beam orbit to one side. The geometrical parameters were optimized by analytic and numerical means in accordance with the beam dynamics of the future collector ring at FAIR. Afterwards, the electromagnetic properties of scaled prototypes were measured on a test bench. The results were in good agreement with the predictions.

  15. Position-sensitive detection of ultracold neutrons with an imaging camera and its implications to spectroscopy

    NASA Astrophysics Data System (ADS)

    Wei, Wanchun; Broussard, L. J.; Hoffbauer, M. A.; Makela, M.; Morris, C. L.; Tang, Z.; Adamek, E. R.; Callahan, N. B.; Clayton, S. M.; Cude-Woods, C.; Currie, S.; Dees, E. B.; Ding, X.; Geltenbort, P.; Hickerson, K. P.; Holley, A. T.; Ito, T. M.; Leung, K. K.; Liu, C.-Y.; Morley, D. J.; Ortiz, Jose D.; Pattie, R. W.; Ramsey, J. C.; Saunders, A.; Seestrom, S. J.; Sharapov, E. I.; Sjue, S. K.; Wexler, J.; Womack, T. L.; Young, A. R.; Zeck, B. A.; Wang, Zhehui

    2016-09-01

    Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15 μm has been achieved, which is equivalent to a UCN energy resolution below 2 pico-electron-volts through the relation δE =m0 gδx. Here, the symbols δE, δx, m0 and g are the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This method allows different types of UCN spectroscopy and other applications.

  16. Position-sensitive CdTe detector using improved crystal growth method

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The feasibility of developing a position-sensitive CdTe detector array for astronomical observations in the hard X-ray, soft gamma ray region is demonstrated. In principle, it was possible to improve the resolution capability for imaging measurements in this region by orders of magnitude over what is now possible through the use of CdTe detector arrays. The objective was to show that CdTe crystals of the quality, size and uniformity required for this application can be obtained with a new high pressure growth technique. The approach was to fabricate, characterize and analyze a 100 element square array and several single-element detectors using crystals from the new growth process. Results show that detectors fabricated from transversely sliced, 7 cm diameter wafers of CdTe exhibit efficient counting capability and a high degree of uniformity over their entire areas. A 100 element square array of 1 sq mm detectors was fabricated and operated.

  17. Position-sensitive CdTe detector using improved crystal growth method

    NASA Astrophysics Data System (ADS)

    1988-09-01

    The feasibility of developing a position-sensitive CdTe detector array for astronomical observations in the hard X-ray, soft gamma ray region is demonstrated. In principle, it was possible to improve the resolution capability for imaging measurements in this region by orders of magnitude over what is now possible through the use of CdTe detector arrays. The objective was to show that CdTe crystals of the quality, size and uniformity required for this application can be obtained with a new high pressure growth technique. The approach was to fabricate, characterize and analyze a 100 element square array and several single-element detectors using crystals from the new growth process. Results show that detectors fabricated from transversely sliced, 7 cm diameter wafers of CdTe exhibit efficient counting capability and a high degree of uniformity over their entire areas. A 100 element square array of 1 sq mm detectors was fabricated and operated.

  18. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  19. Cardiac Position Sensitivity Study in the Electrocardiographic Forward Problem Using Stochastic Collocation and Boundary Element Methods

    PubMed Central

    Swenson, Darrell J.; Geneser, Sarah E.; Stinstra, Jeroen G.; Kirby, Robert M.; MacLeod, Rob S.

    2012-01-01

    The electrocardiogram (ECG) is ubiquitously employed as a diagnostic and monitoring tool for patients experiencing cardiac distress and/or disease. It is widely known that changes in heart position resulting from, for example, posture of the patient (sitting, standing, lying) and respiration significantly affect the body-surface potentials; however, few studies have quantitatively and systematically evaluated the effects of heart displacement on the ECG. The goal of this study was to evaluate the impact of positional changes of the heart on the ECG in the specific clinical setting of myocardial ischemia. To carry out the necessary comprehensive sensitivity analysis, we applied a relatively novel and highly efficient statistical approach, the generalized polynomial chaos-stochastic collocation method, to a boundary element formulation of the electrocardiographic forward problem, and we drove these simulations with measured epicardial potentials from whole-heart experiments. Results of the analysis identified regions on the body-surface where the potentials were especially sensitive to realistic heart motion. The standard deviation (STD) of ST-segment voltage changes caused by the apex of a normal heart, swinging forward and backward or side-to-side was approximately 0.2 mV. Variations were even larger, 0.3 mV, for a heart exhibiting elevated ischemic potentials. These variations could be large enough to mask or to mimic signs of ischemia in the ECG. Our results suggest possible modifications to ECG protocols that could reduce the diagnostic error related to postural changes in patients possibly suffering from myocardial ischemia. PMID:21909818

  20. Frontal but not parietal positivity during source recollection is sensitive to episodic content.

    PubMed

    Peters, Jan; Daum, Irene

    2009-05-01

    Remembering contextual aspects of an event (recollection) is an important function subserved by episodic memory. It has recently been shown that the electrophysiological correlates of recollection differ depending upon the type of information subjects retrieve from episodic memory. In the current study, we investigated whether electrophysiological correlates of memory are also affected by the type of source information retrieved from memory. Subjects studied words that were paired with a sound, a picture of a face or a picture of a scene. During test, they were required to judge whether a given probe word was new or old, and whether it had been paired with a sound, scene or face during study. The parietal old/new effect (400-700 ms post-stimulus), which has previously been associated with recollection, was larger for correct compared to incorrect source retrieval and of comparable magnitude for items from the different encoding conditions. A frontal positivity in the same time window, on the other hand, was sensitive to the type of information subjects retrieved from episodic memory, and showed a differential topography depending on memory content. Our findings confirm and extend previous observations by showing that, when recollection is assessed using an objective performance measure (i.e., source accuracy), frontal brain potentials are sensitive to episodic content. PMID:19429080

  1. Fourier synthesis image reconstruction by use of one-dimensional position-sensitive detectors.

    PubMed

    Kotoku, Jun'ichi; Makishima, Kazuo; Okada, Yuu; Negoro, Hitoshi; Terada, Yukikatsu; Kaneda, Hidehiro; Oda, Minoru

    2003-07-10

    An improvement of Fourier synthesis optics for hard x-ray imaging is described, and the basic performance of the new optics is confirmed through numerical simulations. The original concept of the Fourier synthesis imager utilizes nonposition-sensitive hard x-ray detectors coupled to individual bigrid modulation collimators. The improved concept employs a one-dimensional position-sensitive detector (such as a CdTe strip detector) instead of the second grid layer of each bigrid modulation collimator. This improves the imaging performance in several respects over the original design. One performance improvement is a two-fold increase in the average transmission, from 1/4 to 1/2. The second merit is that both the sine and cosine components can be derived from a single grid-detector module, and hence the number of imaging modules can be halved. Furthermore, it provides information along the depth direction simultaneously. This in turn enables a three-dimensional imaging hard x-ray microscope for medical diagnostics, incorporating radioactive tracers. A conceptual design of such a microscope is presented, designed to provide a field of view of 4 mm and a spatial resolution of 400 microm. PMID:12856730

  2. Position sensitivity of graphene field effect transistors to X-rays

    SciTech Connect

    Cazalas, Edward Moore, Michael E.; Jovanovic, Igor; Sarker, Biddut K.; Childres, Isaac; Chen, Yong P.

    2015-06-01

    Device architectures that incorporate graphene to realize detection of electromagnetic radiation typically utilize the direct absorbance of radiation by graphene. This limits their effective area to the size of the graphene and their applicability to lower-energy, less penetrating forms of radiation. In contrast, graphene-based transistor architectures that utilize the field effect as the detection mechanism can be sensitive to interactions of radiation not only with graphene but also with the surrounding substrate. Here, we report the study of the position sensitivity and response of a graphene-based field effect transistor (GFET) to penetrating, well-collimated radiation (micro-beam X-rays), producing ionization in the substrate primarily away from graphene. It is found that responsivity and response speed are strongly dependent on the X-ray beam distance from graphene and the gate voltage applied to the GFET. To develop an understanding of the spatially dependent response, a model is developed that incorporates the volumetric charge generation, transport, and recombination. The model is in good agreement with the observed spatial response characteristics of the GFET and predicts a greater response potential of the GFET to radiation interacting near its surface. The study undertaken provides the necessary insight into the volumetric nature of the GFET response, essential for development of GFET-based detectors for more penetrating forms of ionizing radiation.

  3. Positive Affect Relevant to Epistemic Curiosity to Reflect Continuance Intention to Join a Hands-On Making Contest

    ERIC Educational Resources Information Center

    Hong, Jon-Chao; Hwang, Ming-Yueh; Szeto, Elson; Tai, Kai-Hsin; Tsai, Chi-Ruei

    2016-01-01

    Hands-on making (e.g., "Maker") has become prevalent in current educational settings. To understand the role that students' epistemic curiosity plays in hands-on making contests, this study explored its correlation to students' positive affect and continuance intention to participate in a hands-on making contest called…

  4. Control system to reduce the effects of friction in drive trains of continuous-path-positioning systems. [Patent application

    DOEpatents

    Green, W.L.

    1980-12-01

    An improved continuous-path-positioning servo-control system is provided for reducing the effects of friction arising at very low cutting speeds in the drive trains of numerically controlled cutting machines, and the like. The improvement comprises a feed forward network for altering the gain of the servo-control loop at low positioning velocities to prevent stick-slip movement of the cutting tool holder being positioned by the control system. The feed forward network shunts conventional lag-compensators in the control loop, or loops, so that the error signal used for positioning varies linearly when the value is small, but being limited for larger values. Thus, at higher positioning speeds there is little effect of the added component upon the control being achieved.

  5. Performance of BF{sub 3} Filled Position Sensitive Neutron Detector

    SciTech Connect

    Desai, Shraddha S.; Devan, Shylaja; Krishna, P. S. R.

    2011-07-15

    {sup 3}He filled position sensitive detectors (PSD)s developed in-house are successfully used for neutron scattering studies at Dhruva. However recent global scarcity of {sup 3}He has made it essential to find an alternative. It is very difficult to meet performance capabilities of {sup 3}He for neutron detection in any of the alternate materials. Among various alternatives, BF{sub 3} gas can be one. We have recently put an effort to evaluate performance of BF{sub 3} based PSD. For that a PSD filled with BF{sub 3} gas at 0.8 bar pressure is fabricated and characterized. Performances of the same with Pu-Be source and at Hi-Q Diffractometer, Dhruva are reported in this paper. Diffraction spectra from standard samples Fe and Si at wavelength 0.783 A were recorded. It is found that while position resolution of the BF{sub 3} filled PSD is comparable but the efficiency is 20 times less than that of a {sup 3}He(12 bar) filled PSD.

  6. Position-sensitive proportional counter with low-resistance metal-wire anode

    DOEpatents

    Kopp, Manfred K.

    1980-01-01

    A position-sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter. A pair of specially designed active-capacitance preamplifiers are used to terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, low-noise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates (>10.sup.6 counts/sec).

  7. A Prototype Three-Dimensional Position Sensitive CdZnTe Detector Array

    SciTech Connect

    Zhang, Feng; He, Zhong; Seifert, Carolyn E.

    2007-08-01

    A new CdZnTe gamma-ray spectrometer system that employs two layers of modular detector arrays is being developed under the collaboration between the University of Michigan and the Pacific Northwest National Labaratory (PNNL). Each layer can accommodate up to three by three 3-dimensional position sensitive CdZnTe gamma-ray spectrometers. This array system is based on the newly developed VAS_UM/TAT4 ASIC readout electronics. Each of the nine detector modules consists of a pixellated CdZnTe detector and a VAS_UM/TAT4 ASIC frontend board. Each 1.5´1.5´1.0 cm3 CdZnTe detector employs an array of 11 by 11 pixellated anodes and a planar cathode. The energy depositions and 3-dimensional positions of individual interactions of each incident gamma ray can be obtained from pulse amplitude, location of each pixel anode and the drift time of electrons. Ten detectors were tested individually and half of them achieved resolution of <1.0% FWHM at 662 keV for single-pixel events (~30% of all 662 keV full energy deposition events). Two of them were tested in a simple array to verify that the upgrade to an array system does not sacrifice the performance of individual detectors. Experimental results of individual detectors and a twodetector array system are presented, and possible causes for several worse performing detectors are discussed.

  8. Position-sensitive change in the transition metal L-edge fine structures

    SciTech Connect

    Gulec, Ahmet; Phillips, Patrick J.; Klie, Robert F.

    2015-10-05

    Studying the structure and composition of solid-state materials on the atomic scale has become nearly routine in transmission electron microscopy with the development of novel electron optics and electron sources. In particular, with spatial resolutions better than 0.1 nm and energy resolution smaller than 100 meV, the stoichiometry, bonding, and coordination can now be examined on similar scales. Aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy (EELS) have played a crucial role in identifying charge ordering, valence, and as spin state transitions in transition metal perovskite oxides. In this letter, we investigate the effects of ever-decreasing electron-probe sizes on the measured near-edge fine-structure of the transition metal core-loss edge using EELS. We find that for certain transition metal perovskites, the position of the electron probe with respect to the atomic column is crucial in determining the correct valence state. Several reasons for the observed position-sensitive EELS fine-structure are discussed.

  9. Performance of resistive-charge position sensitive detectors for RBS/Channeling applications

    NASA Astrophysics Data System (ADS)

    Miranda, P. A.; Wahl, U.; Catarino, N.; Ribeiro da Silva, M.; Alves, E.

    2014-10-01

    The performance of two types of 1×1 cm2 photodiode position sensitive detectors (PSDs) based on resistive charge division was evaluated for their use in Rutherford Backscattering/Channeling (RBS/C) experiments in blocking geometry. Their energy resolution was first determined for ~ 5.5 MeV alpha particles from a radioactive sources, and values of full width half maximum (FWHM) of 22 keV and 33 keV were achieved using a shaping time constant of τ = 2.0 μs. Additional tests were performed using backscattered 4He particles from the 2.0 MeV beam of a Van de Graaff accelerator. While the 22 keV FWHM detector failed after exposure to less than 5×106 cm-24He particles, the other did not show any noticeable deterioration due to radiation damage for a fluence of 4×108 cm-2. For this type of PSD position resolution (τ = 0.5 μs) standard deviations of ΔL = 0.072 mm at ~ 5.5 MeV and ΔL = 0.247 mm at 1.1 MeV were achieved. RBS/Channeling experiments using PSD were performed on several crystalline samples, showing that this setup seems suitable for lattice location studies, particularly for heavy ions implantation (D ≳1015 at /cm2) on light substrates like Si, SiC, and AlN.

  10. Recodifications of Academic Positions and Reiterations of Desire: Change but Continuity in Gendered Subjectivities

    ERIC Educational Resources Information Center

    Lapping, Claudia

    2006-01-01

    This article argues that the analysis of changes in the social position of women needs to distinguish between levels of social practice and psychic subjectification. The argument draws on Lacan's conception of the relationship between subjectivity, desire and sexual difference to describe gendered aspects of subjectivity embedded within the…

  11. Imprinted Numbers: Newborn Chicks' Sensitivity to Number vs. Continuous Extent of Objects They Have Been Reared with

    ERIC Educational Resources Information Center

    Rugani, Rosa; Regolin, Lucia; Vallortigara, Giorgio

    2010-01-01

    Newborn chicks were tested for their sensitivity to number vs. continuous physical extent of artificial objects they had been reared with soon after hatching. Because of the imprinting process, such objects were treated by chicks as social companions. We found that when the objects were similar, chicks faced with choices between 1 vs. 2 or 2 vs. 3…

  12. Bronchoscopic intubation during continuous nasal positive pressure ventilation in the treatment of hypoxemic respiratory failure.

    PubMed

    Barjaktarevic, Igor; Berlin, David

    2015-03-01

    Endotracheal intubation is difficult in patients with hypoxemic respiratory failure who deteriorate despite treatment with noninvasive positive pressure ventilation (NIPPV). Maintaining NIPPV during intubation may prevent alveolar derecruitment and deterioration in gas exchange. We report a case series of 10 nonconsecutive patients with NIPPV failure who were intubated via a flexible bronchoscope during nasal mask positive pressure ventilation. All 10 patients were intubated in the first attempt. Hypotension was the most frequent complication (33%). Mean decrease in oxyhemoglobin saturation during the procedure was 4.7 ± 3.1. This method of intubation may extend the benefits of preoxygenation throughout the whole process of endotracheal intubation. It requires an experienced operator and partially cooperative patients. A prospective trial is necessary to determine the best intubation method for NIPPV failure. PMID:24243561

  13. Parametric stability of continuous shafts, connected to mechanisms with position-dependent inertia

    NASA Astrophysics Data System (ADS)

    Turhan, O.; Koser, K.

    2004-10-01

    Stability of the parametrically excited torsional vibrations of shafts connected to mechanisms with position-dependent inertia is studied via a version of Bolotin's method. The shafts are considered to be torsionally elastic, distributed parameter systems and discretized through a finite element scheme. The mechanisms are modelled by a linearized Eksergian equation of motion. A general method of analysis is described and applied to examples with slider-crank and Scotch-yoke mechanisms.

  14. Sensitivity of MJO propagation to a robust positive Indian Ocean dipole event in the superparameterized CAM

    NASA Astrophysics Data System (ADS)

    Benedict, James J.; Pritchard, Michael S.; Collins, William D.

    2015-12-01

    The superparameterized Community Atmosphere Model (SPCAM) is used to investigate the impact and geographic sensitivity of positive Indian Ocean Dipole (+IOD) sea-surface temperatures (SSTs) on Madden-Julian oscillation (MJO) propagation. The goal is to clarify potentially appreciable +IOD effects on MJO dynamics detected in prior studies by using a global model with explicit convection representation. Prescribed climatological October SSTs and variants of the SST distribution from October 2006, a +IOD event, force the model. Modest MJO convection weakening over the Maritime Continent occurs when either climatological SSTs, or +IOD SST anomalies restricted to the Indian Ocean, are applied. However, severe MJO weakening occurs when either +IOD SST anomalies are applied globally or restricted to the equatorial Pacific. MJO disruption is associated with time-mean changes in the zonal wind profile and lower moist static energy (MSE) in subsiding air masses imported from the Subtropics by Rossby-like gyres. On intraseasonal scales, MJO disruption arises from significantly smaller MSE accumulation, weaker meridional advective moistening, and overactive submonthly eddies that mix drier subtropical air into the path of MJO convection. These results (1) demonstrate that SPCAM reproduces observed time-mean and intraseasonal changes during +IOD episodes, (2) reaffirm the role that submonthly eddies play in MJO propagation and show that such multiscale interactions are sensitive to interannual SST states, and (3) suggest that boreal fall +IOD SSTs local to the Indian Ocean have a significantly smaller impact on Maritime Continent MJO propagation compared to contemporaneous Pacific SST anomalies which, for October 2006, resemble El Niño-like conditions.

  15. EML1 (CNG-Modulin) Controls Light Sensitivity in Darkness and under Continuous Illumination in Zebrafish Retinal Cone Photoreceptors

    PubMed Central

    Mehta, Milap; Tserentsoodol, Nomingerel; Postlethwait, John H.; Rebrik, Tatiana I.

    2013-01-01

    The ligand sensitivity of cGMP-gated (CNG) ion channels in cone photoreceptors is modulated by CNG-modulin, a Ca2+-binding protein. We investigated the functional role of CNG-modulin in phototransduction in vivo in morpholino-mediated gene knockdown zebrafish. Through comparative genomic analysis, we identified the orthologue gene of CNG-modulin in zebrafish, eml1, an ancient gene present in the genome of all vertebrates sequenced to date. We compare the photoresponses of wild-type cones with those of cones that do not express the EML1 protein. In the absence of EML1, dark-adapted cones are ∼5.3-fold more light sensitive than wild-type cones. Previous qualitative studies in several nonmammalian species have shown that immediately after the onset of continuous illumination, cones are less light sensitive than in darkness, but sensitivity then recovers over the following 15–20 s. We characterize light sensitivity recovery in continuously illuminated wild-type zebrafish cones and demonstrate that sensitivity recovery does not occur in the absence of EML1. PMID:24198367

  16. Continuous wavelength tunable laser source with optimum positioning of pivot axis for grating

    DOEpatents

    Pushkarsky, Michael; Amone, David F.

    2010-06-08

    A laser source (10) for generating a continuously wavelength tunable light (12) includes a gain media (16), an optical output coupler (36F), a cavity collimator (38A), a diffraction grating (30), a grating beam (54), and a beam attacher (56). The diffraction grating (30) is spaced apart from the cavity collimator (38A) and the grating (30) cooperates with the optical output coupler (36F) to define an external cavity (32). The grating (30) includes a grating face surface (42A) that is in a grating plane (42B). The beam attacher (56) retains the grating beam (54) and allows the grating beam (54) and the grating (30) to effectively pivot about a pivot axis (33) that is located approximately at an intersection of a pivot plane (50) and the grating plane (42B). As provided herein, the diffraction grating (30) can be pivoted about the unique pivot axis (33) to move the diffraction grating (30) relative to the gain media (16) to continuously tune the lasing frequency of the external cavity (32) and the wavelength of the output light (12) so that the output light (12) is mode hop free.

  17. Betabox: a beta particle imaging system based on a position sensitive avalanche photodiode

    NASA Astrophysics Data System (ADS)

    Dooraghi, A. A.; Vu, N. T.; Silverman, R. W.; Farrell, R.; Shah, K. S.; Wang, J.; Heath, J. R.; Chatziioannou, A. F.

    2013-06-01

    A beta camera has been developed that allows planar imaging of the spatial and temporal distribution of beta particles using a 14 × 14 mm2 position sensitive avalanche photodiode (PSAPD). This camera system, which we call Betabox, can be directly coupled to microfluidic chips designed for cell incubation or other biological applications. Betabox allows for imaging the cellular uptake of molecular imaging probes labeled with charged particle emitters such as 18F inside these chips. In this work, we investigate the quantitative imaging capabilities of Betabox for 18F beta particles, in terms of background rate, efficiency, spatial resolution, and count rate. Measurements of background and spatial resolution are considered both at room temperature (21 °C ± 1 °C) and at an elevated operating temperature (37 °C ± 1 °C), as is often required for biological assays. The background rate measured with a 4 keV energy cutoff is below 2 cph mm-2 at both 21 and 37 °C. The absolute efficiency of Betabox for the detection of 18F positron sources in contact with a PSAPD with the surface passivated from ambient light and damage is 46% ± 1%. The lower detection limit is estimated using the Rose Criterion to be 0.2 cps mm-2 for 1 min acquisitions and a 62 × 62 µm2 pixel size. The upper detection limit is approximately 21 000 cps. The spatial resolution at both 21 and 37 °C ranges from 0.4 mm FWHM at the center of the field of view (FOV), and degrades to 1 mm at a distance of 5 mm away from center yielding a useful FOV of approximately 10 × 10 mm2. We also investigate the effects on spatial resolution and sensitivity that result from the use of a polymer based microfluidic chip. For these studies we place varying layers of low-density polyethylene (LDPE) between the detector and the source and find that the spatial resolution degrades by ˜180 µm for every 100 µm of LDPE film. Sensitivity is reduced by half with the inclusion of ˜200 µm of additional LDPE film. Lastly

  18. Betabox: a beta particle imaging system based on a position sensitive avalanche photodiode

    PubMed Central

    Dooraghi, AA; Vu, NT; Silverman, RW; Farrell, R; Shah, KS; Wang, J; Heath, JR; Chatziioannou, AF

    2013-01-01

    A beta camera has been developed that allows planar imaging of the spatial and temporal distribution of beta particles using a 14 × 14 mm2 position sensitive avalanche photodiode (PSAPD). This camera system, which we call Betabox, can be directly coupled to microfluidic chips designed for cell incubation or other biological applications. Betabox allows for imaging the cellular uptake of molecular imaging probes labeled with charged particle emitters such as 18F inside these chips. In this work, we investigate the quantitative imaging capabilities of Betabox for 18F beta particles, in terms of background rate, efficiency, spatial resolution, and count rate. Measurements of background and spatial resolution are considered both at room temperature (21 °C ± 1 °C) and at an elevated operating temperature (37 °C ± 1 °C), as is often required for biological assays. The background rate measured with a 4 keV energy cutoff is below 2 cph mm−2 at both 21 and 37 °C. The absolute efficiency of Betabox for the detection of 18F positron sources in contact with a PSAPD with the surface passivated from ambient light and damage is 46% ± 1%. The lower detection limit is estimated using the Rose Criterion to be 0.2 cps mm−2 for 1 min acquisitions and a 62 × 62 µm2 pixel size. The upper detection limit is approximately 21 000 cps. The spatial resolution at both 21 and 37 °C ranges from 0.4 mm FWHM at the center of the field of view (FOV), and degrades to 1 mm at a distance of 5 mm away from center yielding a useful FOV of approximately 10 × 10 mm2. We also investigate the effects on spatial resolution and sensitivity that result from the use of a polymer based microfluidic chip. For these studies we place varying layers of low-density polyethylene (LDPE) between the detector and the source and find that the spatial resolution degrades by ~180 µm for every 100 µm of LDPE film. Sensitivity is reduced by half with the inclusion of ~200 µm of additional LDPE film

  19. Prolonged respiratory illness after single overnight continuous positive airway pressure humidification: endotoxin as the suspect.

    PubMed

    Raymond, Lawrence W; Barkley, John E; Langley, Ricky; Sautter, Robert

    2009-12-01

    A patient developed a prolonged respiratory illness after a single overnight use of tap water to humidify air supplied by a constant positive airway pressure (CPAP) device, which she had previously used for six years without difficulty. During those years, she used only distilled water for this purpose, as instructed by her sleep specialist. Analysis of the well water supplying her home showed no microorganisms, metals or other analytes likely to have caused her illness, but endotoxin was found at concentrations well above that recommended by the U.S. Pharmacopeia, as a maximum in water which may be inhaled as an aerosol. PMID:20016436

  20. Continuing evolution of satellite-based geodetic positioning and survey navigation capabilities

    SciTech Connect

    Stansell, T.A. Jr.

    1981-01-01

    The paper reviews progress in the TRANSIT Navigation Satellite System for Offshore oil exploration and land geodetic survey, and examines trends affecting future developments. This report covers three major areas. The first is the field of land geodetic survey. The second area focuses on the evolution of integrated navigation systems for offshore oil exploration. The objective is to show how these systems have matured. Trends affecting the direction of future developments are discussed. Finally, this paper evaluates the coming impact of NAVSTAR, the Global Positioning System. 14 refs.

  1. Coexistence of positive and negative refractive index sensitivity in the liquid-core photonic crystal fiber based plasmonic sensor.

    PubMed

    Shuai, Binbin; Xia, Li; Liu, Deming

    2012-11-01

    We present and numerically characterize a liquid-core photonic crystal fiber based plasmonic sensor. The coupling properties and sensing performance are investigated by the finite element method. It is found that not only the plasmonic mode dispersion relation but also the fundamental mode dispersion relation is rather sensitive to the analyte refractive index (RI). The positive and negative RI sensitivity coexist in the proposed design. It features a positive RI sensitivity when the increment of the SPP mode effective index is larger than that of the fundamental mode, but the sensor shows a negative RI sensitivity once the increment of the fundamental mode gets larger. A maximum negative RI sensitivity of -5500nm/RIU (Refractive Index Unit) is achieved in the sensing range of 1.50-1.53. The effects of the structural parameters on the plasmonic excitations are also studied, with a view of tuning and optimizing the resonant spectrum. PMID:23187403

  2. Multiple Chemical Sensitivity and the Workplace: Current Position and Need for an Occupational Health Surveillance Protocol

    PubMed Central

    Martini, A.; Iavicoli, S.; Corso, L.

    2013-01-01

    Multiple chemical sensitivity, commonly known as environmental illness, is a chronic disease in which exposure to low levels of chemicals causes correlated symptoms of varying intensity. With the continuous introduction of new substances, people with MCS suffer significant limitations to their living environment and frequently to their workplace. This paper describes the current situation as regards MCS and the critical points in its case definition, which is still not generally agreed upon; this makes it difficult to recognize with certainty, especially, its precise relationship with work. Other problems arise in relation to the occupational physician's role in diagnosing and managing the worker with the disorder, the question of low levels of exposure to chemicals, and the best measures possible to prevent it. A diagnostic “route” is proposed, useful as a reference for the occupational physician who is often called in first to identify cases suspected of having this disease and to manage MCS workers. Work-related problems for people with MCS depend not only on occupational exposure but also on the incompatibility between their illness and their work. More occupational physicians need to be “sensitive” to MCS, so that these workers are recognized promptly, the work is adapted as necessary, and preventive measures are promoted in the workplace. PMID:23844274

  3. Theory and Development of Position-Sensitive Quantum Calorimeters. Degree awarded by Stanford Univ.

    NASA Technical Reports Server (NTRS)

    Figueroa-Feliciano, Enectali; White, Nicholas E. (Technical Monitor)

    2001-01-01

    Quantum calorimeters are being developed as imaging spectrometers for future X-ray astrophysics observatories. Much of the science to be done by these instruments could benefit greatly from larger focal-plane coverage of the detector (without increasing pixel size). An order of magnitude more area will greatly increase the science throughput of these future instruments. One of the main deterrents to achieving this goal is the complexity of the readout schemes involved. We have devised a way to increase the number of pixels from the current baseline designs by an order of magnitude without increasing the number of channels required for readout. The instrument is a high energy resolution, distributed-readout imaging spectrometer called a Position-Sensitive Transition-Edge Sensor (POST). A POST is a quantum calorimeter consisting of two Transition-Edge Sensors (TESS) on the ends of a long absorber capable of one-dimensional imaging spectroscopy. Comparing rise time and energy information from the two TESS, the position of the event in the POST is determined. The energy of the event is inferred from the sum of the two pulses. We have developed a generalized theoretical formalism for distributed-readout calorimeters and apply it to our devices. We derive the noise theory and calculate the theoretical energy resolution of a POST. Our calculations show that a 7-pixel POST with 6 keV saturation energy can achieve 2.3 eV resolution, making this a competitive design for future quantum calorimeter instruments. For this thesis we fabricated 7- and 15-pixel POSTS using Mo/Au TESs and gold absorbers, and moved from concept drawings on scraps of napkins to a 32 eV energy resolution at 1.5 keV, 7-pixel POST calorimeter.

  4. Potential of sulfasalazine as a therapeutic sensitizer for CD44 splice variant 9-positive urogenital cancer.

    PubMed

    Takayama, Tatsuya; Kubo, Taro; Morikawa, Ai; Morita, Tatsuo; Nagano, Osamu; Saya, Hideyuki

    2016-05-01

    Cancer stem-like cells (CSCs) with high expression of CD44 splice variant (CD44v) have an enhanced capacity for intracellular reduced glutathione synthesis and defense against reactive oxygen species, resulting in resistance to various therapeutic stresses. Sulfasalazine (SSZ), a drug used in the treatment of rheumatoid arthritis (RA), inhibits glutamate-cystine transport, and suppressed CD44v-dependent tumor growth and increased sensitivity to cytotoxic drugs in an in vivo study. Here, we present two cases of CD44v9-positive urogenital cancer with concomitant treatment with SSZ for RA. Patient 1 was a 62-year-old man who had received SSZ for RA beginning 2 months before the diagnosis of urinary bladder cancer. Although he had multiple metastases to the bladder, abdominal, left cervical and left axillary lymph nodes, and brain, complete response with multidisciplinary therapy was maintained for more than 2 years. Patient 2 was a 74-year-old man with castration-resistant prostate cancer who was diagnosed with RA during chemotherapy and a gradual increase in prostate-specific antigen (PSA) level. When SSZ was added, his PSA value (ng/mL) decreased from 12.93 to 5.58 in only 2 weeks and then quickly rebounded, whereas levels of neuron-specific enolase, a neuroendocrine differentiator and CSC marker, remained almost unchanged. We therefore speculate that SSZ treatment may represent a new adjuvant treatment option for patients with CD44v9-positive urogenital cancer. PMID:27044355

  5. Sit up and smell the roses better: olfactory sensitivity to phenyl ethyl alcohol is dependent on body position.

    PubMed

    Lundström, Johan N; Boyle, Julie A; Jones-Gotman, Marilyn

    2006-03-01

    Previous studies have demonstrated that body position can alter auditory sensitivity. Here we demonstrate for the first time that olfactory sensitivity for the commonly used odor phenyl ethyl alcohol (PEA) (rose odor) is also dependent on body position. By using successive dilutions presented in a staircase protocol, we determined olfactory thresholds for PEA in 36 healthy participants (18 women) in both an upright and a supine position. Participants had a significantly greater olfactory sensitivity when tested in an upright than a supine position, with no significant differences between the sexes. This preliminary study sets the stage for further work on the interaction between olfactory functions and our biology. The implications for olfactory neuroimaging studies are discussed. PMID:16394243

  6. Time-resolved luminescence biosensor for continuous activity detection of protein acetylation-related enzymes based on DNA-sensitized terbium(III) probes.

    PubMed

    Han, Yitao; Li, Hao; Hu, Yufang; Li, Pei; Wang, Huixia; Nie, Zhou; Yao, Shouzhuo

    2015-09-15

    Protein acetylation of histone is an essential post-translational modification (PTM) mechanism in epigenetic gene regulation, and its status is reversibly controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Herein, we have developed a sensitive and label-free time-resolved luminescence (TRL) biosensor for continuous detection of enzymatic activity of HATs and HDACs, respectively, based on acetylation-mediated peptide/DNA interaction and Tb(3+)/DNA luminescent probes. Using guanine (G)-rich DNA-sensitized Tb(3+) luminescence as the output signal, the polycationic substrate peptides interact with DNA with high affinity and subsequently replace Tb(3+), eliminating the luminescent signal. HAT-catalyzed acetylation remarkably reduces the positive charge of the peptides and diminishes the peptide/DNA interaction, resulting in the signal on detection via recovery of DNA-sensitized Tb(3+) luminescence. With this TRL sensor, HAT (p300) can be sensitively detected with a wide linear range from 0.2 to 100 nM and a low detection limit of 0.05 nM. The proposed sensor was further used to continuously monitor the HAT activity in real time. Additionally, the TRL biosensor was successfully applied to evaluating HAT inhibition by two specific inhibitors, anacardic acid and C464, and satisfactory Z'-factors above 0.73 were obtained. Moreover, this sensor is feasible to continuously monitor the HDAC (Sirt1)-catalyzed deacetylation with a linear range from 0.5 to 500 nM and a detection limit of 0.5 nM. The proposed sensor is a convenient, sensitive, and mix-and-read assay, presenting a promising platform for protein acetylation-targeted epigenetic research and drug discovery. PMID:26307596

  7. Position-sensitive spectral splitting with a plasmonic nanowire on silicon chip

    PubMed Central

    Hu, Qing; Xu, Di-Hu; Zhou, Yu; Peng, Ru-Wen; Fan, Ren-Hao; Fang, Nicholas X.; Wang, Qian-Jin; Huang, Xian-Rong; Wang, Mu

    2013-01-01

    On-chip nanophotonics serves as the foundation for the new generation of information technology, but it is challenged by the diffraction limit of light. With the capabilities of confining light into (deep) subwavelength volumes, plasmonics makes it possible to dramatically miniaturize optical devices so as to integrate them into silicon chips. Here we demonstrate that by cascading nano-corrugation gratings with different periodicities on silver nanowires atop silicon, different colors can be spatially separated and chronologically released at different grating junctions. The released light frequency depends on the grating arrangement and corrugation periodicities. Hence the nanowire acts as a spectral splitter for sorting/demultiplexing photons at different nano-scale positions with a ten-femtosecond-level interval. Such nanowires can be constructed further into compact 2D networks or circuits. We believe that this study provides a new and promising approach for realizing spatiotemporal-sensitive spectral splitting and optical signal processing on nanoscales, and for general integration of nanophotonics with microelectronics. PMID:24172838

  8. Development of position-sensitive time-of-flight spectrometer for fission fragment research

    DOE PAGESBeta

    Arnold, C. W.; Tovesson, F.; Meierbachtol, K.; Bredeweg, T.; Jandel, M.; Jorgenson, H. J.; Laptev, A.; Rusev, G.; Shields, D. W.; White, M.; et al

    2014-07-09

    A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEtermination in fission Research (SPIDER) is a 2E–2v spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with α-particles from 229Th and its decay chain and α-particles and spontaneous fission fragments from 252Cf. Each detector module is comprised of thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flightmore » times were measured with 250 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to a precision of 0.5%. As a result, an ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for modestly efficient measurements of light fission fragments with unit mass resolution.« less

  9. Development of position-sensitive time-of-flight spectrometer for fission fragment research

    SciTech Connect

    Arnold, C. W.; Tovesson, F.; Meierbachtol, K.; Bredeweg, T.; Jandel, M.; Jorgenson, H. J.; Laptev, A.; Rusev, G.; Shields, D. W.; White, M.; Blakeley, R. E.; Mader, D. M.; Hecht, A. A.

    2014-07-09

    A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEtermination in fission Research (SPIDER) is a 2E–2v spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with α-particles from 229Th and its decay chain and α-particles and spontaneous fission fragments from 252Cf. Each detector module is comprised of thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flight times were measured with 250 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to a precision of 0.5%. As a result, an ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for modestly efficient measurements of light fission fragments with unit mass resolution.

  10. Measuring the cantilever-position-sensitive detector distance and cantilever curvature for cantilever sensor applications.

    PubMed

    Xu, Meng; Tian, Ye; Coates, M L; Beaulieu, L Y

    2009-09-01

    Measuring cantilever sensor deflections using an optical beam deflection system is more complicated than often assumed. The direction of the reflected beam is dependent on the surface normal of the cantilever, which in turn is dependent on the state of the cantilever. It is often assumed that the cantilever is both straight and perfectly level before the onset of sensing experiments although this assumption, especially the former, is rarely true. Failure to characterize the initial state of the cantilever can lead to irreproducibility in cantilever sensor measurements. We have developed three new methods for characterizing the initial state of the cantilever. In the first case we show how to define the initial angle of inclination beta of the chip on which the cantilever is attached. This method was tested using an aluminum block with a known angle of inclination. A new method for determining the initial distance L(o) between the cantilever and the position-sensitive detector (PSD) is also presented. This parameter which behaves as an amplification factor of the PSD signal is critical for obtaining precise cantilever sensor data. Lastly, we present a method for determining the initial curvature of the cantilever which often results from depositing the sensing platform on the lever. Experiments conducted using deflected cantilevers showed the model to be accurate. The characterization methods presented in this work are simple to use, easy to implement, and can be incorporated into most cantilever sensor setups. PMID:19791971