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Sample records for multi-gap timing rpcs

  1. Progress of R&D and production of timing RPCs in Tsinghua University

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Chen, Huangshan; Ding, Weicheng; Wang, Jingbo; Li, Yuanjing; Cheng, Jianping

    2012-01-01

    Multi-gap resistive plate chamber (MRPC) is a new kind of gas detector. It has good time resolution and high efficiency and has been adopted to construct the full barrel time-of-flight (TOF) detector for the STAR experiment at RHIC. The high rate TOF of CBM is also proposed to be assembled with MRPCs. Tsinghua University is a collaboration member of the two experiments and has made substantial progress on the R&D and production of MRPC. In this paper, we describe the development of low-resistivity glass and high rate MRPC, and the development of 1 m long counter is also described.

  2. Development of mRPCs Using 3D Printed Resistive Plate Stacks

    NASA Astrophysics Data System (ADS)

    See Toh, Jun Hui

    2015-10-01

    ePHENIX will be an experiment at the future Electron-Ion Collider (EIC) to study nucleon spin structure and nuclear effects in nucleon structure. The spin dependent quark-flavor structure of the proton will be studied through semi-inclusive deep inelastic scattering with identified hadrons. These measurements will require superior particle identification capabilities. The EIC group at UIUC aims to develop multi-gap resistive plate chambers (mRPCs) with 10 ps timing resolution for a Time-of-Flight (TOF) detector at EIC. To create a cost efficient detector, mRPCs using 3D printed resistive plate stacks have been constructed and are being evaluated. An mRPC prototype consisting of two stacks of 5 layers of 300 μm gas gaps had been printed using stereolithographic technique. The printed stacks were then sandwiched between printed circuit board plates, which contain pickup electrodes for signal readout and will be connected to high voltage. The presentation will discuss details of the construction of the 3D printed mRPC prototype and will provide first results on efficiency and timing resolution.

  3. Aging Studies of 2nd Generation BaBar RPCs

    SciTech Connect

    Band, H.R.; /SLAC

    2007-09-25

    The BaBar detector, operating at the PEPII B factory of the Stanford Linear Accelerator Center (SLAC), installed over 200 2nd generation Resistive Plate Chambers (RPCs) in 2002. The streamer rates produced by backgrounds and signals from normal BaBar running vary considerably (0.1- >20 Hz/cm2) depending on the layer and position of the chambers, thus providing a broad spectrum test of RPC performance and aging. The lowest rate chambers have performed very well with stable efficiencies averaging 95%. Other chambers had rate-dependant inefficiencies due to Bakelite drying which were reversed by the introduction of humidified gases. RPC inefficiencies in the highest rate regions of the higher rate chambers have been observed and also found to be rate dependant. The inefficient regions grow with time and have not yet been reduced by operation with humidified input gas. Three of these chambers were converted to avalanche mode operation and display significantly improved efficiencies. The rate of production of HF in the RPC exhaust gases was measured in avalanche and streamer mode RPCs and found to be comparable despite the lower current of the avalanche mode RPCs.

  4. Large strip RPCs for the LEPS2 TOF system

    NASA Astrophysics Data System (ADS)

    Tomida, N.; Niiyama, M.; Ohnishi, H.; Tran, N.; Hsieh, C.-Y.; Chu, M.-L.; Chang, W.-C.; Chen, J.-Y.

    2014-12-01

    High time-resolution resistive plate chambers (RPCs) with large-size readout strips are developed for the time-of-flight (TOF) detector system of the LEPS2 experiment at SPring-8. The experimental requirement is a 50-ps time resolution for a strip size larger than 100 cm2/channel. We are able to achieve 50-ps time resolutions with 2.5×100 cm2 strips by directly connecting the amplifiers to strips. With the same time resolution, the number of front-end electronics (FEE) is also reduced by signal addition.

  5. Particle Identification Using Cost Effective mRPC Technology for Time-of-Flight Measurements with Less than 10 ps Time Resolution

    NASA Astrophysics Data System (ADS)

    Shimek, Taylor

    2015-10-01

    This presentation will introduce the use of multi-gap Resistive Plate Chambers (mRPCs) for time of flight (TOF) based particle identification (PID) in nuclear and high-energy physics. The mRPC technology is developed for use in future experiments at the planned Electron Ion Collider, EIC. TOF PID using mRPCs with 10 ps timing resolution will make it possible to precisely determine the flavor content of valence- and sea-quarks in the proton through semi-inclusive deep inelastic scattering with identified pions and kaons. A first mRPC prototype using float glass resistive plates at UIUC has reached a timing resolution of 21 ps. In this presentation I discuss an effort to replace the float glass with cheaper Mylar-based resistive plates. I will also discuss the design and construction of a first prototype and present initial results on signal development, efficiencies and timing resolution of the mRPC prototype.

  6. Study of F- Production in BaBar RPCs

    SciTech Connect

    Band, H.R.; Bellini, F.; Covarelli, R.; Di Marco, E.; D'Orazio, A.; Ferroni, F.; Li Gioi, L.; Lopez, L.; Polci, F.; /Rome U. /INFN, Rome

    2008-02-22

    The BaBar detector has operated over 200 2nd generation Resistive Plate Chambers (RPCs) in the forward endcap since 2002. Many chambers have increased noise rates and high voltage currents. These aging symptoms are correlated with the integrated RPC current as expected, but also depend on the rate and direction of the gas flow, indicating that pollutants produced in the gas can accelerate aging of downstream RPC surfaces. HF produced by decomposition of the Freon 134a component of the BaBar RPC gas in electric discharges has been proposed as the main pollutant. This paper presents measurements of HF production and absorption rates in BaBar RPCs. Since many of the highest rate chambers in the forward endcap were converted to avalanche mode operation, a comparison of HF production in streamer and avalanche mode RPCs is made. Correlations between the HF production rate and other chamber operating conditions were also explored.

  7. The bakelite for the RPCs of the experiment CMS

    NASA Astrophysics Data System (ADS)

    Altieri, S.; Belli, G.; Bruno, G.; Guida, R.; Merlo, M.; Ratti, S. P.; Riccardi, C.; Torre, P.; Vitulo, P.; Mognaschi, E. R.; Abbrescia, M.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Ranieri, A.; Romano, F.

    2000-12-01

    Results from aging tests on the bakelite used for the CMS RPCs are presented. Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation. Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles fluence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS. The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci 137Cs source. A total absorbed dose of 5 Gy was accumulated during an irradiation period of about one month. The test with both neutron and gamma radiation was held at the Triga Mark II 250 kW reactor located in Pavia. A total of 80 h of exposure were accumulated integrating a neutron and gamma dose of about 80 Gy and a fast neutron fluence of some 10 11 cm-2. Experimental data on dose rate in both the test facilities have been compared to simulation output and show a good agreement.

  8. Development of TOF-PET detectors based on the Multi-Gap Resistive Plate Chambers

    NASA Astrophysics Data System (ADS)

    Amaldi, U.; Borghi, G.; Bucciantonio, M.; Kieffer, R.; Samarati, J.; Sauli, F.; Watts, D.

    2015-04-01

    We describe the development, construction and preliminary results obtained with medium-size Multi-Gap Resistive Plate Chambers prototypes designed to detect and localize 511 keV photons for Positron Emission Tomography imaging applications. The devices are intended for in-beam monitoring of the treatment plans throughout deep tumor therapy with hadron beams; emphasis is put on achieving coincidence time resolutions of few hundred ps, in order to exploit optimized reconstruction algorithm and reduce the heavy non-correlated background contributions distinctive of this operation. Using technologies developed for high energy physics experiments, the detectors can be built for covering large areas, thus leading the way to the conception of full-body PET systems at low cost.

  9. Development of 2 m×2 m size glass RPCs for INO

    NASA Astrophysics Data System (ADS)

    Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mohammed, S.; Mondal, N. K.; Nagaraj, P.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

    2012-01-01

    The India-based Neutrino Observatory (INO) collaboration is planning to build a massive 50 kt magnetised iron calorimeter (ICAL) detector to study atmospheric neutrinos and to precisely determine the neutrino oscillation parameters. About 30,000 2 m×2 m size glass Resistive Plate Chambers (RPCs) will be used as active detector elements in ICAL. Starting with a small 30 cm ×30 cm size RPCs, we have now succeeded in developing full size 2 m ×2 m RPCs. The fabrication procedures used for these large size RPCs as well as their performance will be discussed in this paper. We will also present some preliminary results from our studies on SF6 based gas mixtures on the RPC operation and characteristics.

  10. Interaction between fractional Josephson vortices in multi-gap superconductor tunnel junctions

    NASA Astrophysics Data System (ADS)

    Kim, Ju H.

    In a long Josephson junction (LJJ) with two-band superconductors, fractionalization of Josephson vortices (fluxons) can occur in the broken time reversal symmetry state when spatial phase textures (i-solitons) are excited. Excitation of i-solitons in each superconductor layer of the junction, arising due to the presence of two condensates and the interband Josephson effect, leads to spatial variation of the critical current density between the superconductor layers. Similar to the situation in a YBa2 Cu3O7 - x superconductor film grain boundary, this spatial dependence of the crtitical current density can self-generate magnetic flux in the insulator layer, resulting in fractional fluxons with large and small fraction of flux quantum. Similar to fluxons in one-band superconductor LJJ, these fractional fluxons are found to interact with each other. The interaction between large and small fractional fluxons determines the size of a fluxon which includes two (one large and one small) fractional fluxons. We discuss the nature of interaction between fractional fluxons and suggest that i-soliton excitations in multi-gap superconductor LJJs may be probed by using magnetic flux measurements.

  11. Optical Diagnostics of Multi-Gap Gas Switches for Linear Transformer Drivers

    NASA Astrophysics Data System (ADS)

    Sheng, Liang; Li, Yang; Sun, Tieping; Cong, Peitian; Zhang, Mei; Peng, Bodong; Zhao, Jizhen; Yue, Zhiqin; Wei, Fuli; Yuan, Yuan

    2014-07-01

    The trigger characteristics of a multi-gap gas switch with double insulating layers, a square-groove electrode supporter and a UV pre-ionizing structure are investigated aided by a high sensitivity fiber-bundle array detector, a UV fiber detector, and a framing camera, in addition to standard electrical diagnostics. The fiber-bundle-array detector is used to track the turn-on sequence of each electrode gap at a timing precision of 0.6 ns. Each fiber bundle, including five fibers with different azimuth angles, aims at the whole emitting area of each electrode gap and is fed to a photomultiplier tube. The UV fiber detector with a spectrum response of 260-320 nm, including a fused-quartz fiber of 200 μm in diameter and a solar-blinded photomultiplier tube, is adopted to study the effect of UV pre-ionizing on trigger characteristics. The framing camera, with a capacity of 4 frames per shot and an exposure time of 5 ns, is employed to capture the evolution of channel arcs. Based on the turn-on light signal of each electrode gap, the breakdown delay is divided into statistical delay and formative delay. A decrease in both of them, a smaller switch jitter and more channel arcs are observed with lower gas pressure. An increase in trigger voltage can reduce the statistical delay and its jitter, while higher trigger voltage has a relatively small influence on the formative delay and the number of channel arcs. With the UV pre-ionizing structure at 0.24 MPa gas pressure and 60 kV trigger voltage, the statistical delay and its jitter can be reduced by 1.8 ns and 0.67 ns, while the formative delay and its jitter can only be reduced by 0.5 ns and 0.25 ns.

  12. The use of multi-gap resistive plate chambers for in-beam PET in proton and carbon ion therapy

    PubMed Central

    Watts, David; Borghi, Giacomo; Sauli, Fabio; Amaldi, Ugo

    2013-01-01

    On-line verification of the delivered dose during proton and carbon ion radiotherapy is currently a very desirable goal for quality assurance of hadron therapy treatment plans. In-beam positron emission tomography (ibPET), which can provide an image of the β+ activity induced in the patient during irradiation, which in turn is correlated to the range of the ion beam, is one of the modalities for achieving this goal. Application to hadron therapy requires that the scanner geometry be modified from that which is used in nuclear medicine. In particular, PET detectors that allow a sub-nanosecond time-of-flight (TOF) registration of the collinear photons have been proposed. Inclusion of the TOF information in PET data leads to more effective PET sensitivity. Considering the challenges inherent in the ibPET technique, namely limited β+ activity and the effect of biological washout due to blood flow, TOF-PET technologies are very attractive. In this context, the TERA Foundation is investigating the use of resistive plate chambers (RPC) for an ibPET application because of their excellent timing properties and low cost. In this paper we present a novel compact multi-gap RPC (MRPC) module design and construction method, which considering the large number of modules that would be needed to practically implement a high-sensitivity RPC-PET scanner, could be advantageous. Moreover, we give an overview of the efficiency and timing measurements that have been obtained in the laboratory using such single-gap and multi-gap RPC modules. PMID:23824118

  13. Effect of water vapor on the performance of glass RPCs in avalanche mode operation

    NASA Astrophysics Data System (ADS)

    Raveendrababu, K.; Behera, P. K.; Satyanarayana, B.; Mukhopadhayay, S.; Majumdar, N.

    2016-08-01

    We studied the effect of water vapor on the performance of glass Resistive Plate Chambers (RPCs) in the avalanche mode operation. Controlled amount of water vapor was added to the RPC gas mixture that has C2H2F4 as the major component. The deterioration in the performance of RPC was observed while operating with the wet gas and recovered after switching to the standard gas.

  14. Radiation tests of real-sized prototype RPCs for the Phase-2 Upgrade of the CMS Muon System

    NASA Astrophysics Data System (ADS)

    Lee, K. S.; Cho, S. W.; Choi, S. Y.; Hong, B.; Go, Y.; Kang, M. H.; Lim, J. H.; Park, S. K.; Cimmino, A.; Crucy, S.; Fagot, A.; Gul, M.; Rios, A. A. O.; Tytgat, M.; Zaganidis, N.; Aly, S.; Assran, Y.; Radi, A.; Sayed, A.; Singh, G.; Abbrescia, M.; Iaselli, G.; Maggi, M.; Pugliese, G.; Verwilligen, P.; van Doninck, W.; Colafranceschi, S.; Sharma, A.; Benussi, L.; Bianco, S.; Piccolo, D.; Primavera, F.; Bhatnagar, V.; Kumarl, R.; Metha, A.; Singh, J.; Ahmad, A.; Ahmad, M.; Ahmed, W.; Asghar, M. I.; Awan, I. M.; Hassan, Q.; Hoorani, H.; Khan, W. A.; Khurshid, T.; Muhammad, S.; Shah, M. A.; Shahzad, H.; Kim, M. S.; Goutzvitz, M.; Grenier, G.; Lagarde, F.; Laktineh, I. B.; Carpinteyro Bernardino, S.; Uribe Estrada, C.; Pedraza, I.; Severiano, C. B.; Carrillo Moreno, S.; Vazquez Valencia, F.; Pant, L. M.; Buontempo, S.; Cavallo, N.; Esposito, M.; Fabozzi, F.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Orso, I.; Paolucci, P.; Thyssen, F.; Braghieri, A.; Magnani, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Ban, Y.; Qian, S. J.; Choi, M.; Choi, Y.; Goh, J.; Kim, D.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Lomidze, D.; Avila, C.; Cabrera, A.; Sanabria, J. C.; Crotty, I.; Vaitkus, J.

    2016-08-01

    We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for the Phase-2 upgrade of the CMS muon system at high η. In the present study, we constructed real-sized double-gap and four-gap RPCs with gap thicknesses of 1.6 and 0.8 mm, respectively, with 2-mm-thick phenolic high-pressure-laminated (HPL) plates. We examined the prototype RPCs with cosmic rays and with 100-GeV muons provided by the SPS H4 beam line at CERN. To examine the rate capability of the prototype RPCs both at Korea University and at the CERN GIF++ facility, the chambers were irradiated with 137Cs sources providing maximum gamma rates of about 1.5 kHz cm‑2. For the 1.6-mm-thick double-gap RPCs, we found the relatively high threshold on the produced detector charge was conducive to effectively suppressing the rapid increase of strip cluster sizes of muon hits with high voltage, especially when measuring the narrow-pitch strips. The gamma-induced currents drawn in the four-gap RPC were about one-fourth of those drawn in the double-gap RPC. The rate capabilities of both RPC types, proven through the present testing using gamma-ray sources, far exceeded the maximum rate expected in the new high-η endcap RPCs planned for future phase-II runs of the Large Hadron Collider (LHC).

  15. SF 6 quenched gas mixtures for streamer mode operation of RPCs at very low voltages

    NASA Astrophysics Data System (ADS)

    Aielli, G.; Camarri, P.; Cardarelli, R.; Di Ciaccio, A.; Di Stante, L.; Liberti, B.; Paoloni, A.; Pastori, E.; Santonico, R.

    2002-11-01

    In the present paper we describe a search for gases that allow to reduce the energy of the electrical discharge produced in Resistive Plate Chambers (RPCs) operated in streamer mode, by reducing both the operating voltage and the released charge. This can be achieved, with current gas mixtures of argon, tetrafluoroethane (TFE) and isobutane, by reducing the total amount of quenching components (TFE+isobutane) down to 10-15% and compensating for the lower gas quenching power with the addition of small amounts of SF 6. We show here that SF 6, even for concentrations as low as 1% or less, has a strong effect in reducing the delivered charge in low quenched gases and allows to achieve a proper working mode of the RPC even at voltages as low as 4- 5 kV over a 2 mm gas gap.

  16. Performance test of the Multi-gap Resistive Plate Chamber (MRPC) with cosmic ray

    NASA Astrophysics Data System (ADS)

    Ikeda, Michihiko; Akieda, Tomomi; Tomita, Shoko; Ninomiya, Aki

    2014-09-01

    MRPC is a gaseous ionization detector, which a good timing resolution has been used practically in the nuclear and particle physics experiment. A mixed gas of SF6 and Fleon 134a was flowed through the gaps between high resistive plates (500 μm thickness glass). A high electric field of ~2 ×106 [V/m] was applied between the plates. A charged particle passes through the MRPC and causes avalanche amplification. We constructed a relatively small MRPC with a readout pad (20 mm × 50 mm). The development is motivated by feasibility study of the MRPC as a photon tagger at the Research Center for Electron Photon Science (ELPH), Tohoku University. The photon tagger needs a good timing resolution (<100 ps), therefore we studied the small size MRPC, while a large sized MRPCs are widely used in nuclear and particle experiments. The MRPC can operate under the strong magnetic field and thus it can be a good candidate as an electron detector placed in the magnet. We tested the HV dependence of time resolution of the MRPC with cosmic rays. The MRPC will be demonstrated at the open campus of the Tohoku University as an example of nuclear experimental detectors. We will measure the zenith angle and velocity distributions of cosmic ray.

  17. The OPERA RPCs front end electronics; a novel application of LVDS line receiver as low cost discriminator

    NASA Astrophysics Data System (ADS)

    Balsamo, E.; Bergnoli, A.; Bertolin, A.; Brugnera, R.; Carrara, E.; Ciesielski, R.; Dal Corso, F.; Dusini, S.; Garfagnini, A.; Kose, U.; Longhin, A.; Medinaceli, E.; Stanco, L.

    2012-11-01

    The OPERA spectrometer is built from two large dipoles instrumented with around 1000 Resistive Plate Chambers (RPCs), covering a surface of about 3350 m2, and digitally read out by means of almost 27000 strips. The huge number of channels, the inaccessibility of many parts of the detector and the wide uncertainty about the signal amplitude pushed to study a low cost, high sensitivity discriminator, and a very carefully designed layout for the read out system. Here we will present a novel application of LVDS line receiver as discriminator, showing that it exceeds the requirements of a large RPC based detector and offers the intrinsic advantages of a mature technology in terms of costs, reliability and integration scale. We will also present the layout of the read out system showing as the sensitivity and the noise immunity were preserved in a system where the front end electronics is far away from the detector.

  18. ABS plastic RPCs

    SciTech Connect

    Ables, E.; Bionta, R.; Olson, H.; Ott, L.; Parker, E.; Wright, D.; Wuest, C

    1996-02-01

    After investigating a number of materials, we discovered that an ABS plastic doped with a conducting polymer performs well as the resistive electrode in a narrow gap RPC (resistive plate chamber). Operating in the streamer mode, we find efficiencies of 90-96% with low noise and low strip multiplicities. We have also studied a variety of operating gases and found that a mixture containing SF{sub 6}, a non-ozone depleting gas, argon and isobutane gives good streamer mode performance, even with isobutane concentrations of 20% or less.

  19. Performance of timing RPC detectors for relativistic ions and design of a time-of-flight detector (iToF) for the R3B-FAIR experiment for fission and spallation reactions

    SciTech Connect

    Casarejos, E.; Ayyad, Y.; Benlliure, J.; Duran, I.; Paradela, C.; Lopez-Lago, M.; Segade, A.; Vilan, J. A.

    2011-07-01

    Resistive-plate-chambers (RPCs) were proposed to be used to build a time-of-flight detector for relativist heavy ions of the R3B-FAIR experiment, as well as other applications. State-of-the-art reaction codes allow for evaluating the requirements of the detector. The specific needs that working with heavy ions impose about material thicknesses are solved with new design concepts. We built prototypes and investigated the behaviour of RPCs tested with relativistic heavy ions. We measured the efficiency and streamer presence for ions with atomic numbers up to 38. Electron beams were used to study the timing capabilities of the prototypes. (authors)

  20. Msx2 alters the timing of retinal ganglion cells fate commitment and differentiation

    SciTech Connect

    Jiang, Shao-Yun; Wang, Jian-Tao; Dohney Eye Institute, Keck School of Medicine, University of Southern California, 1355 San Pablo Street, DOH 314, Los Angeles, CA 90033

    2010-05-14

    Timing of cell fate commitment determines distinct retinal cell types, which is believed to be controlled by a tightly coordinated regulatory program of proliferation, cell cycle exit and differentiation. Although homeobox protein Msx2 could induce apoptosis of optic vesicle, it is unclear whether Msx2 regulates differentiation and cell fate commitment of retinal progenitor cells (RPCs) to retinal ganglion cells (RGCs). In this study, we show that overexpression of Msx2 transiently suppressed the expression of Cyclin D1 and blocked cell proliferation. Meanwhile, overexpression of Msx2 delayed the expression of RGC-specific differentiation markers (Math5 and Brn3b), which showed that Msx2 could affect the timing of RGCs fate commitment and differentiation by delaying the timing of cell cycle exit of retinal progenitors. These results indicate Msx2 possesses dual regulatory functions in controlling cell cycle progression of retinal RPCs and timing of RGCs differentiation.

  1. ``Hybrid'' multi-gap/single-gap Josephson junctions: Evidence of macroscopic quantum tunneling in superconducting-to-normal switching experiments on MgB2/I/Pb and MgB2/I/Sn junctions

    NASA Astrophysics Data System (ADS)

    Carabello, Steve; Lambert, Joseph; Dai, Wenqing; Li, Qi; Chen, Ke; Cunnane, Daniel; Xi, X. X.; Ramos, Roberto

    We report results of superconducting-to-normal switching experiments on MgB2/I/Pb and MgB2/I/Sn junctions, with and without microwaves. These results suggest that the switching behavior is dominated by quantum tunneling through the washboard potential barrier, rather than thermal excitations or electronic noise. Evidence includes a leveling in the standard deviation of the switching current distribution below a crossover temperature, a Lorentzian shape of the escape rate enhancement peak upon excitation by microwaves, and a narrowing in the histogram of escape counts in the presence of resonant microwave excitation relative to that in the absence of microwaves. These are the first such results reported in ``hybrid'' Josephson tunnel junctions, consisting of multi-gap and single-gap superconducting electrodes.

  2. Simulation of efficiency and time resolution of resistive plate chambers and comparison with experimental data

    NASA Astrophysics Data System (ADS)

    Salim, M.; Jash, A.; Hasan, R.; Satyanarayana, B.; Majumdar, N.; Mukhopadhayay, S.

    2015-04-01

    The India based Neutrino Observatory (INO) collaboration is planning to build a 50 kton magnetized Iron Calorimeter (ICAL) detector to study neutrino oscillations and measure their associated parameters. ICAL will use 28,800 glass Resistive Plate Chambers (RPCs) of 2 m×2 m in size as its active detector elements. These RPCs will be operated in the avalanche mode. As a part of the detector R&D to develop the RPCs required for this detector, we made a comparative study of the effect of Sulphur Hexafluoride (SF6) in the gas mixture on the induced charge using simulation and experimental data in our earlier paper [1]. In this paper, we extend our studies to efficiency and time resolution of the RPC using simulation and experimental data. Several software tools have been used to carry out the simulation. We have calculated the primary interaction parameters using HEED and Geant4. The electron transport parameters have been computed using MAGBOLTZ. We have used nearly exact Boundary Element Method (neBEM) and COMSOL Multiphysics, a Finite Element Method package for calculating the weighting field and the electric field.

  3. Time?

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.

    2013-09-01

    The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

  4. The Time Structure of Hadronic Showers in Calorimeters with Scintillator and with Gas Readout

    NASA Astrophysics Data System (ADS)

    Szalay, Marco

    2014-06-01

    The time structure of hadronic showers is characterized by a prompt component from relativistic particles and by late components predominantly connected to neutrons in the cascade. The sensitivity to this late component thus depends on the choice of the active medium for hadronic calorimeters. The time structure and the differences originating from different readout technologies in a calorimeter with tungsten absorbers are studied with two dedicated setups using scintillator tiles read out with SiPMs and glass RPCs. In both cases, a radial strip of 15 cells with a size of 3 × 3 cm2 each is read out with fast digitizers with deep buffers, providing detailed information on the time structure of the recorded signals over a long sampling window. We will discuss the technical aspects of these systems, and present results on the time structure measurements, which demonstrate sizeable differences in the response of scintillator and gaseous detectors to the neutron components of the hadronic cascade.

  5. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, Rodney J.

    1996-01-01

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources.

  6. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, R.J.

    1996-10-22

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode is disclosed. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources. 12 figs.

  7. A multi-gap magnetorheological clutch with permanent magnet

    NASA Astrophysics Data System (ADS)

    Rizzo, R.; Musolino, A.; Bucchi, F.; Forte, P.; Frendo, F.

    2015-07-01

    This paper describes the design and testing of a novel permanent magnet clutch based on a magnetorheological fluid. It was inspired by a prototype previously developed by the authors and contains a novel gap shape conceived to reduce torque loss in the disengaged operating mode. Several geometries and material arrangements were investigated and the performance in terms of transmissible torque in different operating conditions was assessed using finite element numerical models. The prototype was manufactured and some experimental tests were performed. The new prototype was rated on the basis of performance indices and the design effectiveness was proven by a higher value of efficiency in the disengaged operating mode.

  8. Electrodynamics and intrinsic Josephson effects in multi-gap superconductors

    NASA Astrophysics Data System (ADS)

    Koyama, Tomio; Ota, Yukihiro; Machida, Masahiko

    2010-11-01

    We develop a theory for the Josephson effects in 2-gap intrinsic Josephson junction stacks (IJJ's). The coupled dynamical equations for the phase differences are derived from the low-energy effective Lagrangian. The equations can describe the longitudinal Josephson plasma and the Josephson-Leggett (JL) mode propagating in the direction perpendicular to the junctions. Numerical results for the I - V characteristics are presented. The I - V characteristics shows multiple-branch structure similar to that in Bi-2212 IJJ's. When the Josephson frequency is approached to the JL mode frequency in non-uniform voltage branches, the JL mode is resonantly excited. At the resonant voltage a step-like structure appears in the I - V curves in low-voltage branches.

  9. High-rate timing resistive plate chambers with ceramic electrodes

    NASA Astrophysics Data System (ADS)

    Laso Garcia, A.; Kotte, R.; Naumann, L.; Stach, D.; Wendisch, C.; Wüstenfeld, J.; Kämpfer, B.

    2016-05-01

    We describe recent advances in developing radiation-hard ceramic resistive plate chambers (CRPCs) with Si3N4/SiC composites. Bulk resistivity measurements for this material for different manufacturing processes are reported. The results show that the bulk resistivity ρ can vary between 107 and1013 Ω cm. The varistor type behaviour of the material is analysed. A comparison with other materials used in timing RPCs is given. We describe the assembly and tests of CRPC prototypes in electron and proton beams. For a prototype with ρ ~ 5 ×109 Ω cm, the efficiency of the detectors is 95% at a flux of 2 ×105cm-2s-1. The time resolution at the same flux is about 120 ps. A prototype with ρ ~ 2 ×1010 Ω cm shows an efficiency of about 85% up to fluxes of 5 ×104cm-2s-1 with a time resolution better than 80 ps. The results are compared with RPC models.

  10. A cosmic ray test platform based on high time resolution MRPC technology

    NASA Astrophysics Data System (ADS)

    Chen, Tian-Xiang; Li, Cheng; Sun, Yong-Jie; Chen, Hong-Fang; Shao, Ming; Tang, Ze-Bo; Yang, Rong-Xing; Zhou, Yi; Zhang, Yi-Fei

    2015-05-01

    In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area (90 cm×52 cm) test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate Chamber (MRPC) with excellent time resolution and a high detection efficiency for minimum ionizing particles. The time resolution of the MRPC module used is tested to be ∼80 ps, and the position resolution along the strip is ∼5 mm, while the position resolution perpendicular to the strip is ∼12.7 mm. The platform constructed by four MRPC modules can be used for tracking cosmic rays with a spatial resolution of ∼6.3 mm, and provide a reference time ∼40 ps. Supported by National Natural Science Foundation of China (11275196), and Strategic Priority Research Program of the Chinese Academy of Sciences (XDA03010100)

  11. Particle identification with the ALICE Time-Of-Flight detector at the LHC

    NASA Astrophysics Data System (ADS)

    Alici, A.

    2014-12-01

    High performance Particle Identification system (PID) is a distinguishing characteristic of the ALICE experiment at the CERN Large Hadron Collider (LHC). Charged particles in the intermediate momentum range are identified in ALICE by the Time-Of-Flight (TOF) detector. The TOF exploits the Multi-gap Resistive Plate Chamber (MRPC) technology, capable of an intrinsic time resolution at the level of few tens of ps with an overall efficiency close to 100% and a large operation plateau. The full system is made of 1593 MRPC chambers with a total area of 141 m2, covering the pseudorapidity interval [-0.9,+0.9] and the full azimuthal angle. The ALICE TOF system has shown very stable operation during the first 3 years of collisions at the LHC. In this paper a summary of the system performance as well as main results with data from collisions will be reported.

  12. Real Time Linux - The RTOS for Astronomy?

    NASA Astrophysics Data System (ADS)

    Daly, P. N.

    The BoF was attended by about 30 participants and a free CD of real time Linux-based upon RedHat 5.2-was available. There was a detailed presentation on the nature of real time Linux and the variants for hard real time: New Mexico Tech's RTL and DIAPM's RTAI. Comparison tables between standard Linux and real time Linux responses to time interval generation and interrupt response latency were presented (see elsewhere in these proceedings). The present recommendations are to use RTL for UP machines running the 2.0.x kernels and RTAI for SMP machines running the 2.2.x kernel. Support, both academically and commercially, is available. Some known limitations were presented and the solutions reported e.g., debugging and hardware support. The features of RTAI (scheduler, fifos, shared memory, semaphores, message queues and RPCs) were described. Typical performance statistics were presented: Pentium-based oneshot tasks running > 30kHz, 486-based oneshot tasks running at ~ 10 kHz, periodic timer tasks running in excess of 90 kHz with average zero jitter peaking to ~ 13 mus (UP) and ~ 30 mus (SMP). Some detail on kernel module programming, including coding examples, were presented showing a typical data acquisition system generating simulated (random) data writing to a shared memory buffer and a fifo buffer to communicate between real time Linux and user space. All coding examples were complete and tested under RTAI v0.6 and the 2.2.12 kernel. Finally, arguments were raised in support of real time Linux: it's open source, free under GPL, enables rapid prototyping, has good support and the ability to have a fully functioning workstation capable of co-existing hard real time performance. The counter weight-the negatives-of lack of platforms (x86 and PowerPC only at present), lack of board support, promiscuous root access and the danger of ignorance of real time programming issues were also discussed. See ftp://orion.tuc.noao.edu/pub/pnd/rtlbof.tgz for the StarOffice overheads

  13. Proposed STAR Time of Flight Readout Electronics and DAQ

    NASA Astrophysics Data System (ADS)

    Schambach, Joachim

    2006-04-01

    A novel Time-of-Flight (TOF) subsystem is under design for the STAR detector at RHIC. A total of 3840 Multi-gap Resistive Plate Chambers (MRPC) of 6 pads each are distributed over 120 trays. The total number of channels is 23040. Each TOF tray consists of 192 detector channels and three different types of electronic circuit cards, called "TINO", "TDIG", and "TCPU", listed in order of the data flow. Every 30 trays send their data to a "THUB" card that interfaces to the STAR trigger and transmits the data over a fiber to a fiber receiver which is part of STAR DAQ. The TINO contains the analog front end electronics based on a custom IC called NINO. The output of TINO is passed to the TDIG, where the data are digitized (using the CERN HPTDC ASIC). The TCPU formats and buffers the digital detector information. This formatted data is passed to THUB, which transmits it over an optical fiber to a data receiver in the STAR DAQ room. The architecture of this readout chain and DAQ will be described, and first results from prototypes of the component boards will be discussed.

  14. Antagonism between Gdf6a and retinoic acid pathways controls timing of retinal neurogenesis and growth of the eye in zebrafish.

    PubMed

    Valdivia, Leonardo E; Lamb, Dayna B; Horner, Wilson; Wierzbicki, Claudia; Tafessu, Amanuel; Williams, Audrey M; Gestri, Gaia; Krasnow, Anna M; Vleeshouwer-Neumann, Terra S; Givens, McKenzie; Young, Rodrigo M; Lawrence, Lisa M; Stickney, Heather L; Hawkins, Thomas A; Schwarz, Quenten P; Cavodeassi, Florencia; Wilson, Stephen W; Cerveny, Kara L

    2016-04-01

    Maintaining neurogenesis in growing tissues requires a tight balance between progenitor cell proliferation and differentiation. In the zebrafish retina, neuronal differentiation proceeds in two stages with embryonic retinal progenitor cells (RPCs) of the central retina accounting for the first rounds of differentiation, and stem cells from the ciliary marginal zone (CMZ) being responsible for late neurogenesis and growth of the eye. In this study, we analyse two mutants with small eyes that display defects during both early and late phases of retinal neurogenesis. These mutants carry lesions ingdf6a, a gene encoding a BMP family member previously implicated in dorsoventral patterning of the eye. We show thatgdf6amutant eyes exhibit expanded retinoic acid (RA) signalling and demonstrate that exogenous activation of this pathway in wild-type eyes inhibits retinal growth, generating small eyes with a reduced CMZ and fewer proliferating progenitors, similar togdf6amutants. We provide evidence that RA regulates the timing of RPC differentiation by promoting cell cycle exit. Furthermore, reducing RA signalling ingdf6amutants re-establishes appropriate timing of embryonic retinal neurogenesis and restores putative stem and progenitor cell populations in the CMZ. Together, our results support a model in which dorsally expressedgdf6alimits RA pathway activity to control the transition from proliferation to differentiation in the growing eye. PMID:26893342

  15. Antagonism between Gdf6a and retinoic acid pathways controls timing of retinal neurogenesis and growth of the eye in zebrafish

    PubMed Central

    Valdivia, Leonardo E.; Lamb, Dayna B.; Horner, Wilson; Wierzbicki, Claudia; Tafessu, Amanuel; Williams, Audrey M.; Gestri, Gaia; Krasnow, Anna M.; Vleeshouwer-Neumann, Terra S.; Givens, McKenzie; Young, Rodrigo M.; Lawrence, Lisa M.; Stickney, Heather L.; Hawkins, Thomas A.; Schwarz, Quenten P.; Cavodeassi, Florencia; Wilson, Stephen W.; Cerveny, Kara L.

    2016-01-01

    Maintaining neurogenesis in growing tissues requires a tight balance between progenitor cell proliferation and differentiation. In the zebrafish retina, neuronal differentiation proceeds in two stages with embryonic retinal progenitor cells (RPCs) of the central retina accounting for the first rounds of differentiation, and stem cells from the ciliary marginal zone (CMZ) being responsible for late neurogenesis and growth of the eye. In this study, we analyse two mutants with small eyes that display defects during both early and late phases of retinal neurogenesis. These mutants carry lesions in gdf6a, a gene encoding a BMP family member previously implicated in dorsoventral patterning of the eye. We show that gdf6a mutant eyes exhibit expanded retinoic acid (RA) signalling and demonstrate that exogenous activation of this pathway in wild-type eyes inhibits retinal growth, generating small eyes with a reduced CMZ and fewer proliferating progenitors, similar to gdf6a mutants. We provide evidence that RA regulates the timing of RPC differentiation by promoting cell cycle exit. Furthermore, reducing RA signalling in gdf6a mutants re-establishes appropriate timing of embryonic retinal neurogenesis and restores putative stem and progenitor cell populations in the CMZ. Together, our results support a model in which dorsally expressed gdf6a limits RA pathway activity to control the transition from proliferation to differentiation in the growing eye. PMID:26893342

  16. A novel technique to detect special nuclear material using cosmic rays

    NASA Astrophysics Data System (ADS)

    Thomay, C.; Baesso, P.; Cussans, D.; Davies, J.; Glaysher, P.; Quillin, S.; Robertson, S.; Steer, C.; Vassallo, C.; Velthuis, J.

    2012-12-01

    Resistive plate chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes, due to their excellent time resolution, rate capability, and good spatial resolution. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a muon scattering tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. The required spatial granularity is achieved by using 330 readout strips per RPC with 1.5 mm pitch. The RPCs have shown an efficiency above 99% and an estimated intrinsic resolution below 1.1 mm. Due to these qualities, RPCs serve as excellent candidates for usage in volcano radiography.

  17. The Time of Flight Upgrade for CLAS at 12 GeV

    SciTech Connect

    Graham, Lewis

    2007-10-26

    The Time of Flight (TOF) system is a detection system within the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson National Accelerator Facility. CLAS, being a magnetic toroidal multi-gap spectrometer, is used in the detection of particles and their varying properties. Jefferson National Accelerator Facility is providing an incoming electron beam of energy 6 GeV that is used to probe the structure and production of these particles. The CLAS detector is currently adapted to energies of up to 6 GeV, but with recent approval it will now upgrade to energies of 12 GeV. CLAS consists of drift chambers to determine the charged particle paths, gas Cherenkov counters for electron discrimination, TOF scintillators for particle identification, and an electromagnetic calorimeter for identifying showering electrons and photons. The TOF system, which is our focus, is composed of scintillation counters at the forward angle, and covers an area of 206 meters squared. Therefore, we look to upgrade and construct the TOF system of CLAS and outline strategies of current construction, purpose for design, and outlook for the TOF system upgrade.

  18. The Time of Flight Upgrade for CLAS at 12 GeV

    SciTech Connect

    Lewis Graham

    2007-10-01

    The Time of Flight (TOF) system is a detection system within the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson National Accelerator Facility. CLAS, being a magnetic toroidal multi-gap spectrometer, is used in the detection of particles and their varying properties. Jefferson National Accelerator Facility is providing an incoming electron beam of energy 6 GeV that is used to probe the structure and production of these particles. The CLAS detector is currently adapted to energies of up to 6 GeV, but with recent approval it will now upgrade to energies of 12 GeV. CLAS consists of drift chambers to determine the charged particle paths, gas Cherenkov counters for electron discrimination, TOF scintillators for particle identification, and an electromagnetic calorimeter for identifying showering electrons and photons. The TOF system, which is our focus, is composed of scintillation counters at the forward angle, and covers an area of 206 meters squared. Therefore, we look to upgrade and construct the TOF system of CLAS and outline strategies of current construction, purpose for design, and outlook for the TOF system upgrade

  19. Test of large area glass RPCs at the DAΦNE Test Beam Facility (BTF)

    NASA Astrophysics Data System (ADS)

    Calcaterra, A.; de Sangro, R.; Gamba, D.; Mannocchi, G.; Patteri, P.; Picchi, P.; Piccolo, M.; Ragazzi, S.; Redaelli, N.; Satta, L.; Tabarelli de Fatis, T.; Tonazzo, A.; Trapani, P.; Trinchero, G. C.

    2004-11-01

    The CaPiRe program has been started to develop a new detector design, in order to produce large areas of glass Resistive Plate Chambers (RPC) detectors, overcoming the previous limitations. As a first step we produced our glass RPC detectors (1m2) at General Tecnica exploiting their standard procedures, materials and production techniques simply using 2 mm glass electrodes instead of the bakelite ones. A set of RPC was produced by using pre-coated (silk screen printed) electrodes, while others were produced with the standard graphite coating. All the detectors, together with four old Glass RPC acting as reference, were tested at the DAΦNE Test Beam Facility with 500 MeV electrons in order to study the efficiency in different positions inside the detectors (i.e. near spacers and edges) and to study the detector behavior as a function of the local particle rate.

  20. Presence of retinal pericyte-reactive autoantibodies in diabetic retinopathy patients

    PubMed Central

    Zhang, Lingjun; Li, Yan; Payne, John; Srivastava, Sunil; Fan, Xingjun; Fung, John; Li, Xiaorong; Kern, Timothy S.; Lin, Feng

    2016-01-01

    The loss of retinal pericytes (RPCs) is a hallmark of early stage diabetic retinopathy (DR), but the mechanism underlying RPC death is unclear. Although it was postulated in previous studies using bovine RPCs that autoantibodies against RPCs might develop and induce RPC death, it is unknown whether autoantibodies against cell-surface antigens on human RPCs exist in DR patients, whether such autoantibodies contribute to RPC damage/loss, and if they do, through which mechanism. We screened serum samples from DR patients and controls using primary human RPCs and found that that levels of IgGs reactive to RPCs were significantly higher in the DR group than the control group. Serum samples with higher RPC-reactive IgG levels induced more severe complement-mediated RPC damage than those with lower RPC-reactive IgG levels. We also assessed levels of the complement-activation products C3a, C4a and C5a in these serum samples, and found that serum levels of C3a and C5a, but not C4a, were higher in the DR group than control group. These data provide evidence the first time showing that autoantibodies against RPCs can develop in DR patients, and that these autoantibodies could contribute to pericyte damage through complement activation. PMID:26839120

  1. Time outs

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000756.htm Time outs To use the sharing features on this ... children, 2 to 12 years old. Why Does Time out Work? When you put children in time ...

  2. Flushing Time

    EPA Science Inventory

    The flushing time of an estuary is generally defined as the turnover time of fresh water in the estuary, that is, the time required to replace the fresh water contained in the estuary with freshwater inflow. Thus, the flushing time of an estuary is the ratio of the volume of fres...

  3. Reinventing Time

    ERIC Educational Resources Information Center

    Technology Teacher, 2004

    2004-01-01

    What do planet Earth, a swinging pendulum, a quartz crystal, and a Cesium atom have in common? They have all been used by humans to measure time. They represent humanity's progress through time in measuring time itself. But what is it, really, that humans set out to measure? Before time could be measured, somebody had to decide what to actually…

  4. Chua's Time

    NASA Astrophysics Data System (ADS)

    Buscarino, Arturo; Fortuna, Luigi; Frasca, Mattia

    2013-01-01

    We discuss the relationship between the idea of time of the philosopher Bergson and the concept of time recurrence in chaotic systems. By taking into account the Chua's circuit, we saw that the "Chua's time", i.e., the average recurrence time of trajectories in the Chua's circuit, is able to qualitatively represent the features of the Bergon's time. Numerical and experimental results are presented.

  5. Bleeding time

    MedlinePlus

    Bleeding time is a medical test that measures how fast small blood vessels in the skin stop bleeding. ... until the bleeding stops. The provider records the time it takes for the cuts to stop bleeding.

  6. Entropic Time

    SciTech Connect

    Caticha, Ariel

    2011-03-14

    The formulation of quantum mechanics within the framework of entropic dynamics includes several new elements. In this paper we concentrate on one of them: the implications for the theory of time. Entropic time is introduced as a book-keeping device to keep track of the accumulation of changes. One new feature is that, unlike other concepts of time appearing in the so-called fundamental laws of physics, entropic time incorporates a natural distinction between past and future.

  7. Time Honoured

    ERIC Educational Resources Information Center

    Campbell, Mora; Timmerman, Peter

    2007-01-01

    The vast majority of literature and practices in environmental education focuses on places and spaces. Little attention has been paid to time and temporalities as elements of environments, and the ways in which how we experience time affects our experience of place. This paper is an examination of the ways in which reflection on time can be…

  8. SINGLE LOOP - MULTI GAP RESONATOR FOR WHOLE BODY EPR IMAGING OF MICE AT 1.2 GHZ

    PubMed Central

    Petryakov, Sergey; Samouilov, Alexandre; Kesselring, Eric; Wasowicz, Tomasz; Caia, George L.; Zweier, Jay L.

    2009-01-01

    For whole body EPR imaging of small animals, typically low frequencies of 250–750 MHz have been used due to the microwave losses at higher frequencies and the challenges in designing suitable resonators to accommodate these large lossy samples. However, low microwave frequency limits the obtainable sensitivity. L-band frequencies can provide higher sensitivity, and have been commonly used for localized in vivo EPR spectroscopy. Therefore, it would be highly desirable to develop an L-band microwave resonator suitable for in vivo whole body EPR imaging of small animals such as living mice. A 1.2 GHz 16 gap resonator with inner diameter of 43 mm and 48 mm length was designed and constructed for whole body EPR imaging of small animals. The resonator has good field homogeneity and stability to animal induced motional noise. Resonator stability was achieved with electrical and mechanical design utilizing a fixed position double coupling loop of novel geometry, thus minimizing the number of moving parts. Using this resonator, high quality EPR images of lossy phantoms and living mice were obtained. This design provides good sensitivity, ease of sample access, excellent stability and uniform B1 field homogeneity for in vivo whole body EPR imaging of mice at 1.2 GHz. PMID:17625940

  9. Time Out for Measuring Time.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1983-01-01

    The ability to measure time means being able to arrange events in logical sequences, predict which kinds of events take longer than others, and understand different divisions of time. Teaching methods and class activities that will help children develop skills and concepts concerning time usage are presented. (PP)

  10. TIMING APPARATUS

    DOEpatents

    Bennett, A.E.; Geisow, J.C.H.

    1956-04-17

    The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

  11. Data Quality Monitoring for the CMS Resistive Plate Chamber Detector

    NASA Astrophysics Data System (ADS)

    Cimmino, A.; CMS Collaboration

    2011-06-01

    Resistive Plate Chambers (RPCs), with their excellent time resolution (˜ 2 ns), were chosen as dedicated muon trigger detectors for the CMS experiment. RPCs fulfill the job of muon identification, estimate the momentum and unambiguously assign bunch crossing. The critical tasks of monitoring detector performances, debugging hardware, and certifying recorded data are carried out by the RPC Data Quality Monitoring (DQM) system. We here describe the structure, functionalities, and performances of the DQM applications for the CMS RPC detector.

  12. Time Management

    ERIC Educational Resources Information Center

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as…

  13. Turnover Time

    EPA Science Inventory

    Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

  14. Turnaround time.

    PubMed

    Baumgardner, H W; Boyer, B P; Cavenaugh, B; Keller, C

    1992-01-01

    Advances in instrumentation have enabled laboratories to deliver results much more quickly. But as equipment has advanced so have expectations on turnaround time (TAT), driving up costs in the process. Laboratories must balance the needs of their clients against the need to cover their costs. In this issue, we asked our respondents: How do you address the issue of turnaround time? PMID:10118449

  15. Managing Time.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1991-01-01

    This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household…

  16. Finding time.

    PubMed

    Killeen, Peter R

    2014-01-01

    We understand time through our models of it. These are typically models of our physical chronometers, which we then project into our subjects. A few of these models of the nature of time and its effects on the behavior of organisms are reviewed. New models, such as thermodynamics and spectral decomposition, are recommended for the potential insights that they afford. In all cases, associations are essential features of timing. To make them, time must be discretized by stimuli such as hours, minutes, conditioned stimuli, trials, and contexts in general. Any one association is seldom completely dominant, but rather shares control through proximity in a multidimensional space, important dimensions of which may include physical space and time as rendered by Fourier transforms. PMID:23973706

  17. Pluto Time

    NASA Video Gallery

    If you stood on Pluto at noon and looked around, the landscape would be illuminated about as brightly as on Earth soon after sunset. The team for NASA's New Horizons mission dubbed this "Pluto Time...

  18. Time outs

    MedlinePlus

    ... Time-out technique for discipline. Children's Health Network web site. http://www.childrenshealthnetwork.org/CRS/CRS/pa_ ... a break from negative behavior. Massachusetts Medical Society web site. http://www.massmed.org/patient-care/health- ...

  19. Taking Time

    ERIC Educational Resources Information Center

    Perry, Tonya

    2004-01-01

    The opportunity for students to successfully complete the material increases when teachers take time and care about what they are reading. Students can read the contents of a text successfully if they keep their thoughts moving and ideas developing.

  20. Thrombin Time

    MedlinePlus

    ... monitor unfractionated heparin therapy and to detect heparin contamination in a blood sample. While it is still ... thrombin time may sometimes be ordered when heparin contamination of a sample is suspected or when a ...

  1. Time Out for Time Management.

    ERIC Educational Resources Information Center

    Herr, Judy; And Others

    1995-01-01

    Offers early childhood program administrators time management strategies to increase available time, efficiency, and effectiveness. To manage paper, directors should clear the desk top, use in-out baskets, create a filing system, and handle mail effectively. Tips for managing meetings include preparing an agenda, scheduling meetings for…

  2. Timing During Interruptions in Timing

    ERIC Educational Resources Information Center

    Fortin, Claudette; Bedard, Marie-Claude; Champagne, Julie

    2005-01-01

    Duration and location of breaks in time interval production were manipulated in various conditions of stimulus presentation (Experiments 1-4). Produced intervals shortened and then stabilized as break duration lengthened, suggesting that participants used the break as a preparatory period to restart timing as quickly as possible at the end of the…

  3. About time

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1990-01-01

    Time has historically been a measure of progress of recurrent physical processes. Coordination of future actions, prediction of future events, and assigning order to events are three practical reasons for implementing clocks and signalling mechanisms. In large networks of computers, these needs lead to the problem of synchronizing the clocks throughout the network. Recent methods allow this to be done in large networks with precision around 1 millisecond despite mean message exchange times near 5 milliseconds. These methods are discussed.

  4. Number Time

    ERIC Educational Resources Information Center

    Herrera, Terese A.

    2004-01-01

    This article features Number Time, a site developed by the British Broadcasting Corporation (BBC) for young mathematics learners, located at www.bbc.co.uk/schools/numbertime. The site uses interactive animation to help children in pre-K through grade 2 understand and practice number basics. Users will find online games, videos that tell number…

  5. Geologic Time.

    ERIC Educational Resources Information Center

    Albritton, Claude C., Jr.

    1984-01-01

    Discusses the historical development of the concept of geologic time. Develops the topic by using the major discoveries of geologists, beginning with Steno and following through to the discovery and use of radiometric dating. An extensive reference list is provided. (JM)

  6. Timely arguments.

    PubMed

    Callahan, S

    1991-04-01

    The consideration of time is central to philosophical resolution of issues of protection of human life. The central question is, how much future living is possible at a given point in time. Fetal life merits protection because of the potential for rational self-governance and moral self-consciousness. In contrast, a dying person consciousness or functioning. In the author's view, allowing a comatose person to die reflects the same respect for human life as protecting embryos from abortion. There is no moral justification for using technology to prolong a life when future consciousness is impossible. Viewed from the perspective of future potential, the opposition of many who are part of the antiabortion movement to the removal of feeding tubes from a comatose US woman, Nancy Cruzan, is senseless. PMID:10109972

  7. Doing Time

    PubMed Central

    Yang, Suzanne; Kadouri, Alane; Révah-Lévy, Anne; Mulvey, Edward P.; Falissard, Bruno

    2009-01-01

    Once convicted, the perpetrator of serious crime embarks upon a new journey: the challenge of adjusting to long-term imprisonment. Prisoners’ views of incarceration and the meaning of this experience may affect their later adjustment to life in the community. On the basis of brief narrative responses collected during an epidemiological survey of the psychological health of prisoners in France, this study examined the impact of incarceration on psychological state in a group of 59 inmates serving long sentences. Qualitative content analysis and computer-assisted linguistic analysis (using ALCESTE software) were performed on the textual data of open responses to three standard questions. Using a combination of these two approaches, seven categories of the subjective experience of prisoners in the sample were identified: the Outside World, Others, Punishment, Time, Affects and Impulses, Self-Concept, and Speech. Further qualitative analyses were then performed to compare the responses of Severely Mentally Ill (SMI) subjects and subjects with no psychiatric disorder. These analyses revealed contrasting attitudes towards incarceration. SMI subjects spoke in more hostile and persecutory terms about their experience in prison, attributing suffering to external circumstances, while subjects with no psychiatric disorder evoked similar themes, but with an introspective attitude. The themes evoked by mentally ill individuals in our sample suggest that their reactions to the prison environment arise in part from aspects of their psychiatric symptoms, and this may have relevance to future mental health policy and practices in criminal corrections. PMID:19619895

  8. The Time-Pressure Illusion: Discretionary Time vs. Free Time

    ERIC Educational Resources Information Center

    Goodin, Robert E.; Rice, James Mahmud; Bittman, Michael; Saunders, Peter

    2005-01-01

    People's welfare is a function of both time and money. People can--and, it is said, increasingly do--suffer time-poverty as well as money-poverty. It is undeniably true that people feel increasingly time pressured, particularly in dual-earner households. But much of the time devoted to paid and unpaid tasks is over and above that which is strictly…

  9. The PI3K/Akt/mTOR pathway mediates retinal progenitor cell survival under hypoxic and superoxide stress.

    PubMed

    Sanghera, Karan P; Mathalone, Nurit; Baigi, Ramteen; Panov, Elan; Wang, Dan; Zhao, Xu; Hsu, Howard; Wang, Hai; Tropepe, Vincent; Ward, Michael; Boyd, Shelley R

    2011-06-01

    Oxygen (O₂) tension has emerged as a major regulator of stem cell (SC) biology. Low O₂ concentrations that are toxic to mature cells can confer advantage to stem and early progenitors, while superoxide stress remains a constant threat in aerobic biology and may be partially avoided through sequestration of SCs in the relatively hypoxic stem or regenerative niche. Using primary retina-derived retinal progenitor cells (RPCs) and the R28 progenitor cell line in vitro, we show that RPCs are sensitive to hydrogen peroxide (H₂O₂) induced damage and resistant to moderate levels of low oxygen stress (1% O₂). Under hypoxic conditions, multipotent RPCs upregulate Epo receptors, and Epo, along with insulin, protects against both superoxide- and severe hypoxia- (0.25% O₂) induced apoptosis through activation of the canonical PI3K/Akt/mTOR pathway. This survival advantage is sensitive to inhibitors of PI3K and mTOR. We further demonstrate phosphorylation of the p70S6 ribosomal kinase, a downstream mediator of PI3K/Akt/mTOR and translational activator. Overall, these data confirm that RPCs are sensitive to superoxide stress and resistant to hypoxia and that this resistance is mediated in part by Epo. They further suggest that manipulation of RPCs ex vivo prior to ocular delivery, or the in vivo delivery of exogenous survival factors at the time of cell implantation, could enhance the success of regenerative therapies aimed to restore sight. PMID:21463685

  10. Neuropsychology of Timing and Time Perception

    ERIC Educational Resources Information Center

    Meck, W.H.

    2005-01-01

    Interval timing in the range of milliseconds to minutes is affected in a variety of neurological and psychiatric populations involving disruption of the frontal cortex, hippocampus, basal ganglia, and cerebellum. Our understanding of these distortions in timing and time perception are aided by the analysis of the sources of variance attributable…

  11. Time on Your Hands: Modeling Time

    ERIC Educational Resources Information Center

    Finson, Kevin; Beaver, John

    2007-01-01

    Building physical models relative to a concept can be an important activity to help students develop and manipulate abstract ideas and mental models that often prove difficult to grasp. One such concept is "time". A method for helping students understand the cyclical nature of time involves the construction of a Time Zone Calculator through a…

  12. Prothrombin time (PT)

    MedlinePlus

    PT; Pro-time; Anticoagulant-prothrombin time; Clotting time: protime; INR; International normalized ratio ... PT is measured in seconds. Most of the time, results are given as what is called INR ( ...

  13. Times of Our Lives.

    ERIC Educational Resources Information Center

    Ramsay, John G.

    2001-01-01

    Lists activities parents can build into their schedules to strengthen their families and help their students succeed, noting the three keys to scheduling during the school year (clarity, discipline, and flexibility). Activities involve: getting ready time, teaching time, friend time, playtime, reading time, down time, adventure time, practice…

  14. The ciliary marginal zone of the zebrafish retina: clonal and time-lapse analysis of a continuously growing tissue

    PubMed Central

    Wan, Yinan; Almeida, Alexandra D.; Rulands, Steffen; Chalour, Naima; Muresan, Leila; Wu, Yunmin; Simons, Benjamin D.; He, Jie; Harris, William A.

    2016-01-01

    Clonal analysis is helping us understand the dynamics of cell replacement in homeostatic adult tissues (Simons and Clevers, 2011). Such an analysis, however, has not yet been achieved for continuously growing adult tissues, but is essential if we wish to understand the architecture of adult organs. The retinas of lower vertebrates grow throughout life from retinal stem cells (RSCs) and retinal progenitor cells (RPCs) at the rim of the retina, called the ciliary marginal zone (CMZ). Here, we show that RSCs reside in a niche at the extreme periphery of the CMZ and divide asymmetrically along a radial (peripheral to central) axis, leaving one daughter in the peripheral RSC niche and the other more central where it becomes an RPC. We also show that RPCs of the CMZ have clonal sizes and compositions that are statistically similar to progenitor cells of the embryonic retina and fit the same stochastic model of proliferation. These results link embryonic and postembryonic cell behaviour, and help to explain the constancy of tissue architecture that has been generated over a lifetime. PMID:26893352

  15. Resistive Plate Chambers for the Pierre Auger array upgrade

    NASA Astrophysics Data System (ADS)

    Lopes, L.; Assis, P.; Blanco, A.; Cerda, M. A.; Carolino, N.; Cunha, O.; Ferreira, M.; Fonte, P.; Mendes, L.; Palka, M.; Pereira, A.; Pimenta, M.; Tomé, B.

    2014-10-01

    In the framework of the Pierre Auger Observatory upgrade, Resistive Plate Chambers (RPCs) have been proposed as a dedicated detector to better estimate the muonic component of Extensive Air Showers (EAS), further constraining the nature of the cosmic rays and hadronic interactions that take place in Extensive Air Showers development. RPCs are a very interesting option to fulfill the requirements: to cover large areas at low cost; particle counting from one to thousands of particles; few ns time resolution and outdoor standalone operation with very low maintenance. The present work refers to the latest advances and outcomes in order to ensure the capability of RPCs to fulfill the totality of the Auger upgrade requirements.

  16. Calibration of the RPC charge readout in the ARGO-YBJ experiment

    NASA Astrophysics Data System (ADS)

    Aielli, G.; Bacci, C.; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, P.; Budano, A.; Bussino, S.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, P.; Chen, S. Z.; Chen, T. L.; Chen, Y.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Alí Staiti, G.; Danzengluobu; Dattoli, M.; de Mitri, I.; D'Ettorre Piazzoli, B.; de Vincenzi, M.; di Girolamo, T.; Ding, X. H.; di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, F.; Galeotti, P.; Gargana, R.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Montini, P.; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, P.; Qu, X. B.; Rossi, E.; Ruggieri, F.; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, Jilong; Zhang, Jianli; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.

    2012-01-01

    The charge readout of Resistive Plate Chambers (RPCs) is implemented in the ARGO-YBJ experiment to measure the charged particle density of the shower front up to 104/m2, enabling the study of the primary cosmic rays with energies in the “knee” region. As the first time for RPCs being used this way, a telescope with RPCs and scintillation detectors is setup to calibrate the number of charged particles hitting a RPC versus its charge readout. Air shower particles are taken as the calibration beam. The telescope was tested at sea level and then moved to the ARGO-YBJ site for coincident operation with the ARGO-YBJ experiment. The charge readout shows good linearity with the particle density in the dynamic range (up to 200/m2).

  17. Intelligence, Inspection Time, and Decision Time.

    ERIC Educational Resources Information Center

    Bates, Timothy C.; Eysenck, Hans J.

    1993-01-01

    Relationships among Multidimensional Aptitude Battery scores, inspection time, choice reaction time, and the odd-man procedure were investigated for 63 female and 25 male adults. No significant relationships were found for these mental speed measures and the Eysenck Personality Questionnaire-Revised dimensions of extraversion, neuroticism, and…

  18. Make time to move

    MedlinePlus

    Exercise - time to move; Weight loss - time to move; Obesity - time to move ... Getting regular exercise benefits your health in many ways: Strengthens your heart and lungs Lowers your risk for heart disease and ...

  19. Time's Arrows Today

    NASA Astrophysics Data System (ADS)

    Savitt, Steven F.

    1997-06-01

    Introduction; Part I. Cosmology and Time's Arrow: 1. Time, gravity, and quantum mechanics W. Unruh; 2. Cosmology, time's arrow, and that old double standard H. Price; Part II. Quantum Theory and Time's Arrow: 3. Time's arrow and the quantum measurement problem A. Leggett; 4. Time, decoherence, and 'reversible' measurements P. Stamp; 5. Time flows, non-locality, and measurement in quantum mechanics S. McCall; 6. Stochastically branching spacetime topology R. Douglas; Part III. Thermodynamics and Time's Arrow: 7. The elusive object of desire: in pursuit of the kinetic equations and the second law L. Sklar; 8. Time in experience and in theoretical description of the world L. Sklar; 9. When and why does entropy increase? M. Barrett and E. Sober; Part IV. Time Travel and Time's Arrow: 10. Closed causal chains P Horwich; 11. Recent work on time travel J. Earman.

  20. From Time to Time: Processing Time Reference Violations in Dutch

    ERIC Educational Resources Information Center

    Dragoy, Olga; Stowe, Laurie A.; Bos, Laura S.; Bastiaanse, Roelien

    2012-01-01

    Time reference in Indo-European languages is marked on the verb. With tensed verb forms, the speaker can refer to the past (wrote, has written), present (writes, is writing) or future (will write). Reference to the past through verb morphology has been shown to be particularly vulnerable in agrammatic aphasia and both agrammatic and…

  1. On Time-II: Newton's Time.

    ERIC Educational Resources Information Center

    Raju, C. K.

    1991-01-01

    A study of time in Newtonian physics is presented. Newton's laws of motion, falsifiability and physical theories, laws of motion and law of gravitation, and Laplace's demon are discussed. Short bibliographic sketches of Laplace and Karl Popper are included. (KR)

  2. Time domain reflectometry in time variant plasmas

    NASA Technical Reports Server (NTRS)

    Scherner, Michael J.

    1992-01-01

    The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a specified static electron density profile, are used. A study of the effects of Doppler shifts resulting from moving density fluctuations in the electron density profile of the sheath is included. Varying electron density levels corrupt time domain and distance measurements. Reducing or modulating the electron density levels of a given electron density profile affects the time domain response of a plasma and results in motion of the turning point, and the effective motion has a significant effect on measuring electron density locations.

  3. Occupational Cohort Time Scales

    PubMed Central

    Roth, H. Daniel

    2015-01-01

    Purpose: This study explores how highly correlated time variables (occupational cohort time scales) contribute to confounding and ambiguity of interpretation. Methods: Occupational cohort time scales were identified and organized through simple equations of three time scales (relational triads) and the connections between these triads (time scale web). The behavior of the time scales was examined when constraints were imposed on variable ranges and interrelationships. Results: Constraints on a time scale in a triad create high correlations between the other two time scales. These correlations combine with the connections between relational triads to produce association paths. High correlation between time scales leads to ambiguity of interpretation. Conclusions: Understanding the properties of occupational cohort time scales, their relational triads, and the time scale web is helpful in understanding the origins of otherwise obscure confounding bias and ambiguity of interpretation. PMID:25647318

  4. Synchronized time stamp support

    SciTech Connect

    Kowalkowski, J.

    1994-02-16

    New software has been added to IOC core to maintain time stamps. The new software has the ability to maintain time stamps over all IOCs on a network. The purpose of this paper is to explain how EPICS will synchronize the time stamps. In addition, this paper will explain how to configure and use the new EPICS time stamp support software.

  5. Time and Teaching

    ERIC Educational Resources Information Center

    McEwan, Anna E.

    2012-01-01

    This essay invites reflection on the phenomena of time as it impacts the day-to-day life of teachers. It also explores assumptions about time and teaching in three areas: first, beliefs about the force of time and the teacher's struggle to control it; second, beliefs about the potential of time and the benefits of its passing for teachers and…

  6. Time Management for Directors

    ERIC Educational Resources Information Center

    Jaffe, Ellen Hofstetter

    2005-01-01

    Time management is a skill. Like any new skill, it takes time and commitment to develop. A frequent complaint of center directors is not having enough time. Most work extremely long hours and still feel they are not getting enough done. This article presents ideas on how to manage time and work smarter, not harder. These ideas are the following:…

  7. Review of time scales. [Universal Time-Ephemeris Time-International Atomic Time

    NASA Technical Reports Server (NTRS)

    Guinot, B.

    1974-01-01

    The basic time scales are presented: International Atomic Time, Universal Time, and Universal Time (Coordinated). These scales must be maintained in order to satisfy specific requirements. It is shown how they are obtained and made available at a very high level of precision.

  8. Ignition timing control

    SciTech Connect

    Lambert, J.E.; Bedross, G.M.

    1993-05-25

    An engine ignition control system for controlling the timing of the spark for initiating burning in the combustion chamber of a four stroke cycle, single cylinder, internal combustion engine is described; said engine having a cylinder, a piston in said cylinder, a crankshaft connected to said piston, said piston being adapted to reciprocate between a top dead center position and a bottom dead center position; a speed sensor means for developing periodic sensor voltage timing pulses, the cycle time between timing pulses being an indication of engine crankshaft speed; means for developing ignition timing pulses, each timing pulse having a leading edge corresponding to a voltage change in a timing voltage pulse and a trailing edge corresponding to an opposite voltage change in a timing voltage pulse; means for developing a spark voltage including an ignition coil and a source of ignition coil current, said spark voltage occurring at a coil primary current interrupt point; means for measuring in real-time, cycle time and a timing pulse time for one engine cycle; and means for computing an optimum delay time from the leading edge of a timing pulse for said one cycle to said interrupt point whereby combustion is initiated at a time in advance of the top dead center position.

  9. [Time perceptions and representations].

    PubMed

    Tordjman, S

    2015-09-01

    Representations of time and time measurements depend on subjective constructs that vary according to changes in our concepts, beliefs, societal needs and technical advances. Similarly, the past, the future and the present are subjective representations that depend on each individual's psychic time and biological time. Therefore, there is no single, one-size-fits-all time for everyone, but rather a different, subjective time for each individual. We need to acknowledge the existence of different inter-individual times but also intra-individual times, to which different functions and different rhythms are attached, depending on the system of reference. However, the construction of these time perceptions and representations is influenced by objective factors (physiological, physical and cognitive) related to neuroscience which will be presented and discussed in this article. Thus, studying representation and perception of time lies at the crossroads between neuroscience, human sciences and philosophy. Furthermore, it is possible to identify several constants among the many and various representations of time and their corresponding measures, regardless of the system of time reference. These include the notion of movements repeated in a stable rhythmic pattern involving the recurrence of the same interval of time, which enables us to define units of time of equal and invariable duration. This rhythmicity is also found at a physiological level and contributes through circadian rhythms, in particular the melatonin rhythm, to the existence of a biological time. Alterations of temporality in mental disorders will be also discussed in this article illustrated by certain developmental disorders such as autism spectrum disorders. In particular, the hypothesis will be developed that children with autism would need to create discontinuity out of continuity through stereotyped behaviors and/or interests. This discontinuity repeated at regular intervals could have been

  10. Physiologic time: A hypothesis

    NASA Astrophysics Data System (ADS)

    West, Damien; West, Bruce J.

    2013-06-01

    The scaling of respiratory metabolism with body size in animals is considered by many to be a fundamental law of nature. One apparent consequence of this law is the scaling of physiologic time with body size, implying that physiologic time is separate and distinct from clock time. Physiologic time is manifest in allometry relations for lifespans, cardiac cycles, blood volume circulation, respiratory cycle, along with a number of other physiologic phenomena. Herein we present a theory of physiologic time that explains the allometry relation between time and total body mass averages as entailed by the hypothesis that the fluctuations in the total body mass are described by a scaling probability density.

  11. Time in Cortical Circuits

    PubMed Central

    Shadlen, Michael N.; Jazayeri, Mehrdad; Nobre, Anna C.; Buonomano, Dean V.

    2015-01-01

    Time is central to cognition. However, the neural basis for time-dependent cognition remains poorly understood. We explore how the temporal features of neural activity in cortical circuits and their capacity for plasticity can contribute to time-dependent cognition over short time scales. This neural activity is linked to cognition that operates in the present or anticipates events or stimuli in the near future. We focus on deliberation and planning in the context of decision making as a cognitive process that integrates information across time. We progress to consider how temporal expectations of the future modulate perception. We propose that understanding the neural basis for how the brain tells time and operates in time will be necessary to develop general models of cognition. SIGNIFICANCE STATEMENT Time is central to cognition. However, the neural basis for time-dependent cognition remains poorly understood. We explore how the temporal features of neural activity in cortical circuits and their capacity for plasticity can contribute to time-dependent cognition over short time scales. We propose that understanding the neural basis for how the brain tells time and operates in time will be necessary to develop general models of cognition. PMID:26468192

  12. Screen time and children

    MedlinePlus

    "Screen time" is a term used for activities done in front of a screen, such as watching TV, working on a computer, or playing video games. Screen time is sedentary activity, meaning you are being physically ...

  13. Mean Solar Time

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The time system in use for most civil and many astronomical purposes and based on the motion of a hypothetical object called the mean Sun, the right ascension of which increases from day to day at a uniform rate. The local mean time is defined to be the local hour angle of the mean Sun plus 12 h. Greenwich mean time is taken as the standard for reference; the term Universal Time (UT) is synonymou...

  14. Time Management. Revised.

    ERIC Educational Resources Information Center

    Halverson, Don E.

    This booklet presents concepts and applications of effective time management to help administrators learn to utilize their time most effectively, thereby accomplishing their most worthwhile objectives in the shortest amount of time. Although the booklet is designed to be self-administered, the greatest benefits should be derived in a group setting…

  15. America's Family Time Famine.

    ERIC Educational Resources Information Center

    Mattox, Jr., William R.

    1990-01-01

    Parents spend increasingly less time with their children because of the pressures of dual careers and single parenthood. Economic pressures and social values have affected sharing of family time. Studies show both parents and children consider spending time together the most important element in improving family life. (BC)

  16. Time Is Money

    ERIC Educational Resources Information Center

    Oxley, Diana; Baete, Glenn

    2012-01-01

    One has heard it before: time is money, especially when it comes to adding time for instruction to the school day. When budgets are tight and relief is nowhere in sight, how can schools afford to implement a reform as costly as adding instructional time? It's a daunting task, yet current federal educational priorities tied to federal funding…

  17. Expectancy, Attention, and Time.

    ERIC Educational Resources Information Center

    Barnes, Ralph; Jones, Mari Riess

    2000-01-01

    Examined the influence of contextual timing manipulations on prospective time judgments through 7 experiments involving a total of 199 college students. Discusses results in terms of various stimulus-based models of prospective time judgments, including those that appeal to attentional periodicities and entrainment. (SLD)

  18. Quantum Operation Time Reversal

    SciTech Connect

    Crooks, Gavin E.

    2008-03-25

    The dynamics of an open quantum system can be described by a quantum operation: A linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes toward equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

  19. SNS TIMING SYSTEM.

    SciTech Connect

    NELSON,J.R.; OERTER,B.; SHEA,T.; SIBLEY,C.

    2001-11-27

    A modern physics facility must synchronize the operation of equipment over a wide area. The primary purpose of the site wide SNS synchronization and timing system is to synchronize the operation of the LINAC, accumulator ring and neutron choppers and to distribute appropriate timing signals to accelerator systems, including the Injector, LINAC, Accumulator Ring and Experimental Facilities. Signals to be distributed include the ring RF clock, real-time timing triggers, machine mode and other informational events. Timing triggers and clocks from the SNS synchronization and timing system are used to synchronize hardware operations including the MEBT beam chopper, RF turn on, synchronous equipment state changes, as well as data acquisition for power supplies and beam diagnostics equipment. This paper will describe the timing equipment being designed for the SNS facility and discuss the tradeoffs between conflicting demands of the accelerator and neutron chopper performance due to AC power grid frequency fluctuations.

  20. Time card entry system

    SciTech Connect

    Montierth, B.S.

    1996-05-01

    The Time Card Entry System was developed to interface with the DOE Headquarters Electronic Time and Attendance (ETA) system. It features pop-up window pick lists for Work Breakdown Structure Numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills US Government/OMB requirements before Timekeepers process the data at the end of the two week payroll cycle using ETA. Tours of Duty (e.g. ten hour day, four day week with Friday through Sunday off), established in the ETA system, are imported into the Time Card Entry System by the Timekeepers. An individual`s Tour of Duty establishes the basis for validation of time of day and number of hours worked per day. At the end of the two week cycle, data is exported by the Timekeepers from the Time Card Entry System into ETA data files.

  1. Biomarker time out.

    PubMed

    Petzold, Axel; Bowser, Robert; Calabresi, Paolo; Zetterberg, Henrik; Uitdehaag, Bernard M J

    2014-10-01

    The advancement of knowledge relies on scientific investigations. The timing between asking a question and data collection defines if a study is prospective or retrospective. Prospective studies look forward from a point in time, are less prone to bias and are considered superior to retrospective studies. This conceptual framework conflicts with the nature of biomarker research. New candidate biomarkers are discovered in a retrospective manner. There are neither resources nor time for prospective testing in all cases. Relevant sources for bias are not covered. Ethical questions arise through the time penalty of an overly dogmatic concept. The timing of sample collection can be separated from testing biomarkers. Therefore the moment of formulating a hypothesis may be after sample collection was completed. A conceptual framework permissive to asking research questions without the obligation to bow to the human concept of calendar time would simplify biomarker research, but will require new safeguards against bias. PMID:24557857

  2. When time matters.

    PubMed

    Theadore, Jason C

    2011-01-01

    The most important organizational resource is energy. The most important resource in time management is energy. Managing energy, not time, can help create encouraging time management skills and appropriate work life balance. Once a leader understands that time should be spent on things that are important instead of everything that is urgent, you can begin to develop a balance that will support your values, your family, and your organization. When leaders find meaningful ways to add a sense of purpose to their work they can personally improve themselves and their organizations. If your personal values do not align with the values of your organization you will never work with a true sense of purpose. Make the time to manage your energy. You will be surprised how much free time you find. PMID:21793462

  3. On Time Performance Pressure

    NASA Technical Reports Server (NTRS)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

    Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

  4. It's About Time!

    NASA Technical Reports Server (NTRS)

    Clark, Tom

    2000-01-01

    Everything we do in VLBI is connected to time. In this contribution, we review 28 orders of magnitude of the spectrum of time ranging from a few hundred femtoseconds (i.e. one degree of phase at X-band - Pi x 10(exp -13) seconds) upwards to tens of millions of years (i.e. ten million years Pi x 10(exp 14) seconds). In this discussion, we will pay special attention to the relation between the underlying oscillator (the frequency standard that defines a clock's rate) and the time kept by the clock (which counts the oscillations of the frequency standard). We will consider two different types of time - time kept by counting an atomic frequency standard (Hydrogen Maser or Cesium), and time reckoned by the rotation of the Earth underneath the stars and sun.

  5. Time functions revisited

    NASA Astrophysics Data System (ADS)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  6. Intrinsic time quantum geometrodynamics

    NASA Astrophysics Data System (ADS)

    Ita, Eyo Eyo; Soo, Chopin; Yu, Hoi-Lai

    2015-08-01

    Quantum geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together with its ground state and primordial quantum fluctuations. Cotton-York potential dominates at early times when the universe was small; the ground state naturally resolves Penrose's Weyl curvature hypothesis, and thermodynamic and gravitational "arrows of time" point in the same direction. Ricci scalar potential corresponding to Einstein's general relativity emerges as a zero-point energy contribution. A new set of fundamental commutation relations without Planck's constant emerges from the unification of gravitation and quantum mechanics.

  7. Variable camshaft timing system

    SciTech Connect

    Butterfield, R.P.; Smith, F.R.

    1989-09-05

    This patent describes an improvement in a variable camshaft timing system for an internal combustion engine having intake and exhaust valves and a camshaft for each of the intake and exhaust valves, an intake sprocket and an exhaust sprocket keyed to their respective camshaft, only one of the camshafts being directly driven by an engine crankshaft, and a timing chain engaging both sprockets. The improvement comprising a single bracket carrying at least one idler sprocket engaging the timing chain, the bracket being mounted for movement to alter the timing relationship between the intake and exhaust sprockets.

  8. Time-varying BRDFs.

    PubMed

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials. PMID:17356224

  9. Time Functions as Utilities

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2010-09-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K + relation (Seifert’s relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg’s and Levin’s theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K + (or Seifert) relation which indeed turns out to be the intersection of the time or temporal orderings. This result tells us in which circumstances it is possible to recover the chronological or causal relation starting from the set of time or temporal functions allowed by the spacetime. Moreover, it is proved that a chronological spacetime in which the closure of the causal relation is transitive (for instance a reflective spacetime) admits a semi-time function. Along the way a new proof avoiding smoothing techniques is given that the existence of a time function implies stable causality, and a new short proof of the equivalence between K-causality and stable causality is given which takes advantage of Levin’s theorem and smoothing techniques.

  10. Time for Bed Game

    MedlinePlus

    ... a Friend Who Cuts? Babysitting: Time for Bed Game KidsHealth > For Teens > Babysitting: Time for Bed Game Print A A A Text Size What Kids ... kids to bed can be tough sometimes! This game introduces children to the concept of getting enough ...

  11. Floquet Time Crystals.

    PubMed

    Else, Dominic V; Bauer, Bela; Nayak, Chetan

    2016-08-26

    We define what it means for time translation symmetry to be spontaneously broken in a quantum system and show with analytical arguments and numerical simulations that this occurs in a large class of many-body-localized driven systems with discrete time-translation symmetry. PMID:27610834

  12. Tips for Taming Time

    ERIC Educational Resources Information Center

    LaBelle, Sandy

    2006-01-01

    This article shares seven easy ideas to help teachers tame their time-management problems. To reduce the amount of mail that makes it to one's desk, the author suggests using the "Chicken Pox" technique to limit the number of times a piece of mail is handled. With this technique, it is not necessary to make an immediate decision regarding the…

  13. ZERO-TIME INDICATOR

    DOEpatents

    Sander, H.H.

    1960-08-30

    The travel time of a nuclear shock wave from its point of origin to a location can be determined accurately by an apparatus for noting and comparably recording both zerotime, as indicated by the electromagnetic transient associated with the nuclear detonation, and shock wave arrival time.

  14. More Recess Time, Please!

    ERIC Educational Resources Information Center

    Chang, Rong; Coward, Fanni Liu

    2015-01-01

    Students in Shanghai, China, get much more recess time than their U.S. counterparts throughout their education. As U.S. education reform efforts seek ways of raising achievement, they have begun replacing recess with academic time. The lesson from Shanghai is that this may not be the best strategy. But whether the Shanghai system of more and…

  15. TIME CALIBRATED OSCILLOSCOPE SWEEP

    DOEpatents

    Owren, H.M.; Johnson, B.M.; Smith, V.L.

    1958-04-22

    The time calibrator of an electric signal displayed on an oscilloscope is described. In contrast to the conventional technique of using time-calibrated divisions on the face of the oscilloscope, this invention provides means for directly superimposing equal time spaced markers upon a signal displayed upon an oscilloscope. More explicitly, the present invention includes generally a generator for developing a linear saw-tooth voltage and a circuit for combining a high-frequency sinusoidal voltage of a suitable amplitude and frequency with the saw-tooth voltage to produce a resultant sweep deflection voltage having a wave shape which is substantially linear with respect to time between equal time spaced incremental plateau regions occurring once each cycle of the sinusoidal voltage. The foregoing sweep voltage when applied to the horizontal deflection plates in combination with a signal to be observed applied to the vertical deflection plates of a cathode ray oscilloscope produces an image on the viewing screen which is essentially a display of the signal to be observed with respect to time. Intensified spots, or certain other conspicuous indications corresponding to the equal time spaced plateau regions of said sweep voltage, appear superimposed upon said displayed signal, which indications are therefore suitable for direct time calibration purposes.

  16. Time - A Traveler's Guide

    NASA Astrophysics Data System (ADS)

    Pickover, Clifford A.

    1999-09-01

    "Bucky Fuller thought big," Wired magazine recently noted, "Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." In his newest book, Cliff Pickover outdoes even himself, probing a mystery that has baffled mystics, philosophers, and scientists throughout history--What is the nature of time?In Time: A Traveler's Guide , Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe--time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning and an end? What is eternity? Pickover's book offers a stimulating blend of Chopin, philosophy, Einstein, and modern physics, spiced with diverting side-trips to such topics as the history of clocks, the nature of free will, and the reason gold glitters. Numerous diagrams ensure readers will have no trouble following along.By the time we finish this book, we understand a wide variety of scientific concepts pertaining to time. And most important, we will understand that time travel is, indeed, possible.

  17. Time Management. Revised.

    ERIC Educational Resources Information Center

    Halverson, Don E.

    Effective management of time involves utilizing a few basic rules. These rules can be summarized as follows: (1) determine your goals and objectives in all major aspects of your life; (2) devote at least 25 percent of your work week to personal improvement in your managerial role; (3) block out a large amount of time daily for planning in your…

  18. Time Here, Time There, Time Everywhere: Teaching Young Children Time through Daily Routine

    ERIC Educational Resources Information Center

    Lee, Joohi; Lee, Joo Ok; Fox, Jill

    2009-01-01

    According to Piaget, 5- or 6-year-old children gradually acquire the concept of time based on events (Piaget, 1969). In his experiment of investigating children's time concepts, Piaget found that children of these ages were able to place pictures based on sequential events with some errors; the younger children made more errors. The National…

  19. Time in quantum gravity

    NASA Astrophysics Data System (ADS)

    Zeh, H. D.

    1988-01-01

    The intrinsic time concept of quantum gravity allows one to derive thermodynamical and quantum mechanical time arrows correlated with cosmic expansion only. Tube-like standing waves subject to a ``final'' condition may resemble unparametrised orbits of the universe, with ``quantum Poincaré cycles'' coinciding with its durations. A recent criticism by Qadir is answered.

  20. Survivability Versus Time

    NASA Technical Reports Server (NTRS)

    Joyner, James J., Sr.

    2014-01-01

    Develop Survivability vs Time Model as a decision-evaluation tool to assess various emergency egress methods used at Launch Complex 39B (LC 39B) and in the Vehicle Assembly Building (VAB) on NASAs Kennedy Space Center. For each hazard scenario, develop probability distributions to address statistical uncertainty resulting in survivability plots over time and composite survivability plots encompassing multiple hazard scenarios.

  1. The metrology of time.

    PubMed

    Arias, Elisa Felicitas

    2005-09-15

    Measuring time is a continuous activity, an international and restless enterprise hidden in time laboratories spread all over the planet. The Bureau International des Poids et Mesures is charged with coordinating activities for international timekeeping and it makes use of the world's capacity to produce a remarkably stable and accurate reference time-scale. Commercial atomic clocks beating the second in national laboratories can reach a stability of one part in 10(14) over a 5 day averaging time, compelling us to research the most highly performing methods of remote clock comparison. The unit of the international time-scale is the second of the International System of Units, realized with an uncertainty of the order 10(-15) by caesium fountains. Physicists in a few time laboratories are making efforts to gain one order of magnitude in the uncertainty of the realization of the second, and more refined techniques of time and frequency transfer are in development to accompany this progress. Femtosecond comb technology will most probably contribute in the near future to enhance the definition of the second with the incorporation of optical clocks. We will explain the evolution of the measuring of time, current state-of-the-art measures and future challenges. PMID:16147510

  2. Time and Teaching

    NASA Astrophysics Data System (ADS)

    Zielinski, Theresa Julia; Brooks, David W.; Crippen, Kent J.; March, Joe L.

    2001-06-01

    Time management is an important issue for teachers and students. This article discusses teachers' use of time from the perspective of curriculum and instruction. Average high school students spend fewer than 5 hours per week in outside-of-class study; average college students spend about 20 hours. Procrastination, often viewed in a negative light by teachers, usually pays off so well for college students that seniors become better at it than freshmen. Three suggestions for designing instruction are: test early and often; do not waste the best students' time in an effort to improve overall performance; and use engaging activities that motivate students to give of their time. The impact of computers on curricula is a double-edged sword. Time must be devoted to teaching the use of applications, but the programs reduce busywork. Will this turn out to be a simple tradeoff, or will the programs make us much more efficient so that less time is required? Will computer programs ultimately lead to an expanded criterion for expertise, thus demanding even more time to become an expert? These issues are described and suggestions for controlling time during instruction are provided.

  3. Time for Learning

    ERIC Educational Resources Information Center

    Johnston, J. Howard

    2009-01-01

    The amount of time allocated for learning and the way that time is used is one of the few variables that can be influenced rather directly by school leaders. Fortunately, it is also a variable that has shown consistent links to student performance. Now that schools are focused directly, and in some cases exclusively, on student achievement, there…

  4. Babies Need Tummy Time

    MedlinePlus

    ... Facts ​​​​​​​​​​​​​​​​​​​​​​​​​​​ Printer-Friendly Email Page Skip sharing on social media links Babies Need Tummy Time! Page Content Tummy Time is not ...

  5. Part-Time Faculty.

    ERIC Educational Resources Information Center

    Clery, Suzanne B.

    2001-01-01

    This study relates information regarding the role part-time faculty members fill in colleges and universities. Data are from the U.S. Department of Education's National Survey of Postsecondary Faculty, 1999. In that year, 2 of every 5 faculty members taught on a part-time basis, and they taught nearly 40% of all classes and students that were…

  6. A Time Management Study.

    ERIC Educational Resources Information Center

    Gothberg, Helen M.; And Others

    In order to evaluate time management practices among managers of large academic libraries, questionnaires were mailed to 189 library directors. A total of 158 surveys were returned for a response rate of 82%. Items used to collect data in the questionnaire were based on time management literature and were grouped into five categories: (1) a…

  7. Task Time Tracker

    Energy Science and Technology Software Center (ESTSC)

    2013-07-24

    This client-side web app tracks the amount of time spent on arbitrary tasks. It allosw the creation of an unlimited number of arbitrarily named tasks ans via simple interactions, tracks the amount of time spent working on the drfined tasks.

  8. TIMING OF SHOCK WAVES

    DOEpatents

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  9. Changing time and emotions

    PubMed Central

    Geoffard, Pierre-Yves; Luchini, Stéphane

    2010-01-01

    In this paper, we consider that our experience of time (to come) depends on the emotions we feel when we imagine future pleasant or unpleasant events. A positive emotion such as relief or joy associated with a pleasant event that will happen in the future induces impatience. Impatience, in our context, implies that the experience of time up to the forthcoming event expands. A negative emotion such as grief or frustration associated with an unpleasant event that will happen in the future triggers anxiety. This will give the experience of time contraction. Time, therefore, is not exogeneously given to the individual and emotions, which link together events or situations, are a constitutive ingredient of the experience of time. Our theory can explain experimental evidence that people tend to prefer to perform painful actions earlier than pleasurable ones, contrary to the predictions yielded by the standard exponential discounting framework. PMID:20026465

  10. Timing optimization control

    SciTech Connect

    Johnson, E.A.; Leung, C.; Schira, J.J.

    1983-03-01

    A closed loop timing optimization control for an internal combustion engine closed about the instantaneous rotational velocity of the engine's crankshaft is disclosed herein. The optimization control computes from the instantaneous rotational velocity of the engine's crankshaft, a signal indicative of the angle at which the crankshaft has a maximum rotational velocity for the torque impulses imparted to the engine's crankshaft by the burning of an air/fuel mixture in each of the engine's combustion chambers and generates a timing correction signal for each of the engine's combustion chambers. The timing correction signals, applied to the engine timing control, modifies the time at which the ignition signal, injection signals or both are generated such that the rotational velocity of the engine's crankshaft has a maximum value at a predetermined angle for each torque impulse generated optimizing the conversion of the combustion energy to rotational torque.

  11. Digital time delay

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay provides a first output signal at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits latch the high resolution data to form a first synchronizing data set. A selected time interval has been preset to internal counters and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses count down the counters to generate an internal pulse delayed by an internal which is functionally related to the preset time interval. A second LCD corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD to generate a second set of synchronizing data which is complementary with the first set of synchronizing data for presentation to logic circuits. The logic circuits further delay the internal output signal with the internal pulses. The final delayed output signal thereafter enables the output pulse generator to produce the desired output pulse at the preset time delay interval following input of the trigger pulse.

  12. Time synchronized video systems

    NASA Technical Reports Server (NTRS)

    Burnett, Ron

    1994-01-01

    The idea of synchronizing multiple video recordings to some type of 'range' time has been tried to varying degrees of success in the past. Combining this requirement with existing time code standards (SMPTE) and the new innovations in desktop multimedia however, have afforded an opportunity to increase the flexibility and usefulness of such efforts without adding costs over the traditional data recording and reduction systems. The concept described can use IRIG, GPS or a battery backed internal clock as the master time source. By converting that time source to Vertical Interval Time Code or Longitudinal Time Code, both in accordance with the SMPTE standards, the user will obtain a tape that contains machine/computer readable time code suitable for use with editing equipment that is available off-the-shelf. Accuracy on playback is then determined by the playback system chosen by the user. Accuracies of +/- 2 frames are common among inexpensive systems and complete frame accuracy is more a matter of the users' budget than the capability of the recording system.

  13. Generative pulsar timing analysis

    NASA Astrophysics Data System (ADS)

    Lentati, L.; Alexander, P.; Hobson, M. P.

    2015-03-01

    A new Bayesian method for the analysis of folded pulsar timing data is presented that allows for the simultaneous evaluation of evolution in the pulse profile in either frequency or time, along with the timing model and additional stochastic processes such as red spin noise, or dispersion measure variations. We model the pulse profiles using `shapelets' - a complete orthonormal set of basis functions that allow us to recreate any physical profile shape. Any evolution in the profiles can then be described as either an arbitrary number of independent profiles, or using some functional form. We perform simulations to compare this approach with established methods for pulsar timing analysis, and to demonstrate model selection between different evolutionary scenarios using the Bayesian evidence. The simplicity of our method allows for many possible extensions, such as including models for correlated noise in the pulse profile, or broadening of the pulse profiles due to scattering. As such, while it is a marked departure from standard pulsar timing analysis methods, it has clear applications for both new and current data sets, such as those from the European Pulsar Timing Array and International Pulsar Timing Array.

  14. Parallel time integration software

    Energy Science and Technology Software Center (ESTSC)

    2014-07-01

    This package implements an optimal-scaling multigrid solver for the (non) linear systems that arise from the discretization of problems with evolutionary behavior. Typically, solution algorithms for evolution equations are based on a time-marching approach, solving sequentially for one time step after the other. Parallelism in these traditional time-integrarion techniques is limited to spatial parallelism. However, current trends in computer architectures are leading twards system with more, but not faster. processors. Therefore, faster compute speeds mustmore » come from greater parallelism. One approach to achieve parallelism in time is with multigrid, but extending classical multigrid methods for elliptic poerators to this setting is a significant achievement. In this software, we implement a non-intrusive, optimal-scaling time-parallel method based on multigrid reduction techniques. The examples in the package demonstrate optimality of our multigrid-reduction-in-time algorithm (MGRIT) for solving a variety of parabolic equations in two and three sparial dimensions. These examples can also be used to show that MGRIT can achieve significant speedup in comparison to sequential time marching on modern architectures.« less

  15. Ultrasonic Time Reversal Mirrors

    NASA Astrophysics Data System (ADS)

    Fink, Mathias; Montaldo, Gabriel; Tanter, Mickael

    2004-11-01

    For more than ten years, time reversal techniques have been developed in many different fields of applications including detection of defects in solids, underwater acoustics, room acoustics and also ultrasound medical imaging and therapy. The essential property that makes time reversed acoustics possible is that the underlying physical process of wave propagation would be unchanged if time were reversed. In a non dissipative medium, the equations governing the waves guarantee that for every burst of sound that diverges from a source there exists in theory a set of waves that would precisely retrace the path of the sound back to the source. If the source is pointlike, this allows focusing back on the source whatever the medium complexity. For this reason, time reversal represents a very powerful adaptive focusing technique for complex media. The generation of this reconverging wave can be achieved by using Time Reversal Mirrors (TRM). It is made of arrays of ultrasonic reversible piezoelectric transducers that can record the wavefield coming from the sources and send back its time-reversed version in the medium. It relies on the use of fully programmable multi-channel electronics. In this paper we present some applications of iterative time reversal mirrors to target detection in medical applications.

  16. Parallel time integration software

    SciTech Connect

    2014-07-01

    This package implements an optimal-scaling multigrid solver for the (non) linear systems that arise from the discretization of problems with evolutionary behavior. Typically, solution algorithms for evolution equations are based on a time-marching approach, solving sequentially for one time step after the other. Parallelism in these traditional time-integrarion techniques is limited to spatial parallelism. However, current trends in computer architectures are leading twards system with more, but not faster. processors. Therefore, faster compute speeds must come from greater parallelism. One approach to achieve parallelism in time is with multigrid, but extending classical multigrid methods for elliptic poerators to this setting is a significant achievement. In this software, we implement a non-intrusive, optimal-scaling time-parallel method based on multigrid reduction techniques. The examples in the package demonstrate optimality of our multigrid-reduction-in-time algorithm (MGRIT) for solving a variety of parabolic equations in two and three sparial dimensions. These examples can also be used to show that MGRIT can achieve significant speedup in comparison to sequential time marching on modern architectures.

  17. VARIABLE TIME DELAY MEANS

    DOEpatents

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  18. Time Series Explorer

    NASA Astrophysics Data System (ADS)

    Loredo, Thomas

    The key, central objectives of the proposed Time Series Explorer project are to develop an organized collection of software tools for analysis of time series data in current and future NASA astrophysics data archives, and to make the tools available in two ways: as a library (the Time Series Toolbox) that individual science users can use to write their own data analysis pipelines, and as an application (the Time Series Automaton) providing an accessible, data-ready interface to many Toolbox algorithms, facilitating rapid exploration and automatic processing of time series databases. A number of time series analysis methods will be implemented, including techniques that range from standard ones to state-of-the-art developments by the proposers and others. Most of the algorithms will be able to handle time series data subject to real-world problems such as data gaps, sampling that is otherwise irregular, asynchronous sampling (in multi-wavelength settings), and data with non-Gaussian measurement errors. The proposed research responds to the ADAP element supporting the development of tools for mining the vast reservoir of information residing in NASA databases. The tools that will be provided to the community of astronomers studying variability of astronomical objects (from nearby stars and extrasolar planets, through galactic and extragalactic sources) will revolutionize the quality of timing analyses that can be carried out, and greatly enhance the scientific throughput of all NASA astrophysics missions past, present, and future. The Automaton will let scientists explore time series - individual records or large data bases -- with the most informative and useful analysis methods available, without having to develop the tools themselves or understand the computational details. Both elements, the Toolbox and the Automaton, will enable deep but efficient exploratory time series data analysis, which is why we have named the project the Time Series Explorer. Science

  19. Characteristics of cosmic time

    NASA Astrophysics Data System (ADS)

    Salopek, D. S.

    1995-11-01

    The nature of cosmic time is illuminated using Hamilton-Jacobi theory for general relativity. For problems of interest to cosmology, one may solve for the phase of the wave functional by using a line integral in superspace. Each contour of integration corresponds to a particular choice of time hypersurface, and each yields the same answer. In this way, one can construct a covariant formalism where all time hypersurfaces are treated on an equal footing. Using the method of characteristics, explicit solutions for an inflationary epoch with several scalar fields are given. The theoretical predictions of double inflation are compared with recent galaxy data and large angle microwave background anistropies.

  20. AMS Time Lapse Installation

    NASA Video Gallery

    A time lapse video compilation of the installation of the Alpha Magnetic Spectrometer on the International Space Station’s starboard truss using the station’s robotic arm, Canadarm2, during the...

  1. Middle Management Time Usage.

    ERIC Educational Resources Information Center

    Dorin, Patrick C.; Mansergh, Gerald G.

    1980-01-01

    Elementary principals and industrial managers are involved in similar job activities, but they differ in the amount of time spent in each activity and in the degree of interaction with others. (Author/JM)

  2. Time, Temporality, Now

    NASA Astrophysics Data System (ADS)

    Atmanspacher, Harald; Ruhnau, Eva

    The essays in this topical volume inquire into one of the most fundamental issues of philosophy and of the cognitive and natural sciences: the riddle of time. The central feature is the tension between the experience and the conceptualization of time, reflecting an apparently unavoidable antinomy of subjective first-person accounts and objective traditional science. Is time based in the physics of inanimate matter, or does it originate in the operation of our minds? Is it essential for the constitution of reality, or is it just an illusion? Issues of time, temporality, and nowness are paradigms for interdisciplinary work in many contemporary fields of research. The authors of this volume discuss profoundly the mutual relationships and inspiring perspectives. They address a general audience.

  3. Drug Retention Times

    SciTech Connect

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user

  4. Drug Retention Times

    SciTech Connect

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  5. Transit Timing Variations

    NASA Video Gallery

    The animation shows the difference between planet transit timing of single and multiple planet system. In tightly packed planetary systems, the gravitational pull of the planets among themselves ca...

  6. Time to Go Local!

    MedlinePlus

    ... Bar Home Current Issue Past Issues Time to Go Local! Past Issues / Winter 2007 Table of Contents ... MedlinePlus.gov health topic pages, you will find "Go Local" links that take you to information about ...

  7. Predictive spark timing method

    SciTech Connect

    Tang, D.L.; Chang, M.F.; Sultan, M.C.

    1990-01-09

    This patent describes a method of determining spark time in a spark timing system of an internal combustion engine having a plurality of cylinders and a spark period for each cylinder in which a spark occurs. It comprises: generating at least one crankshaft position reference pulse for each spark firing event, the reference pulse nearest the next spark being set to occur within a same cylinder event as the next spark; measuring at least two reference periods between recent reference pulses; calculating the spark timing synchronously with crankshaft position by performing the calculation upon receipt of the reference pulse nearest the next spark; predicting the engine speed for the next spark period from at least two reference periods including the most recent reference period; and based on the predicted speed, calculating a spark time measured from the the reference pulse nearest the next spark.

  8. Angles, Time, and Proportion

    ERIC Educational Resources Information Center

    Pagni, David L.

    2005-01-01

    This article describes an investigation making connections between the time on an analog clock and the angle between the minute hand and the hour hand. It was posed by a middle school mathematics teacher. (Contains 8 tables and 6 figures.)

  9. Time-resolved holography

    NASA Astrophysics Data System (ADS)

    Rebane, A.; Feinberg, Jack

    1991-05-01

    IN a conventional hologram, a photographic film records the interference pattern of monochromatic light, scattered from the object to be imaged, with a reference beam of unscattered light. Illumination of the developed film with a replica of the reference beam then creates a virtual image of the original object. Here we show how a molecular resonance can be used to record an interference pattern between light signals that arrive at different times, and with this technique create a hologram with time resolution. Using a timed reference pulse as a Might shutter', we can record holographic images selectively, according to the time taken by light travelling from the object to the hologram. We use this method to image an object behind a semi-opaque screen, and indicate how a similar method could be used to inspect objects embedded in a dense scattering medium. Ultimately, this technique might be applied to the medical imaging of tumours.

  10. Timing control system

    NASA Technical Reports Server (NTRS)

    Wiker, Gordon A. (Inventor); Wells, Jr., George H. (Inventor)

    1989-01-01

    A timing control system is disclosed which is particularly useful in connection with simulated mortar shells. Special circuitry is provided to assure that the shell does not overshoot, but rather detonates early in case of an improper condition; this ensures that ground personnel will not be harmed by a delayed detonation. The system responds to an externally applied frequency control code which is configured to avoid any confusion between different control modes. A premature detonation routine is entered in case an improper time-setting signal is entered, or if the shell is launched before completion of the time-setting sequence. Special provisions are also made for very early launch situations and improper detonator connections. An alternate abort mode is provided to discharge the internal power supply without a detonation in a manner that can be externally monitored, thereby providing a mechanism for non-destructive testing. The abort mode also accelerates the timing function for rapid testing.

  11. Imagining Deep Time (Invited)

    NASA Astrophysics Data System (ADS)

    Talasek, J.

    2013-12-01

    Imagining Deep Time '...the mind seemed to grow giddy by looking so far into the abyss of time.' John Playfair (1748 -1819), scientist and mathematician "Man cannot afford to conceive of nature and exclude himself." Emmit Gowin, photographer 'A person would have to take themselves out of the human context to begin to think in terms of geologic time. They would have to think like a rock.' Terry Falke, photographer The term Deep Time refers to the vastness of the geological time scale. First conceived in the 18th century, the development of this perspective on time has been pieced together like a jigsaw puzzle of information and observations drawn from the study of the earth's structure and discovered fossilized flora and fauna. Deep time may possibly be the greatest contribution made by the discipline of geology forever impacting our perception of earth and our relationship to it. How do we grasp such vast concepts as deep time which relates to the origins of the earth or cosmic time which relates to the origins of the universe - concepts that exist far beyond the realm of human experience? Further more how do we communicate this? The ability to visualize is a powerful tool of discovery and communication for the scientist and it is part and parcel of the work of visual artists. The scientific process provides evidence yet it is imagination on the part of the scientists and artists alike that is needed to interpret that information. This exhibition represents an area where both rational and intuitive thinking come together to explore this question of how we relate to the vastness of time. The answer suggested by the combination of art work assembled here suggests that we do so through a combination of visual metaphors (cycles, circles, arrows, trajectories) and visual evidence (rock formations, strata, fossils of fauna and flora) while being mediated through various technologies. One provides factual and empirical evidence while the other provides a way of grasping

  12. Time Scales: Terrestrial

    NASA Astrophysics Data System (ADS)

    Petit, G.; Murdin, P.

    2000-11-01

    Terrestrial time is at present derived from atomic clocks. The SI second, the unit of time of the international system of units, has been defined since 1967 in terms of a hyperfine transition of the cesium atom and the best primary frequency standards now realize it with a relative uncertainty of a few parts in 1015, which makes it the most accurately measurable physical quantity. INTERNATIONAL A...

  13. Time Card Entry System

    Energy Science and Technology Software Center (ESTSC)

    1996-05-07

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two weekmore » payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual''s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.« less

  14. Time Card Entry System

    SciTech Connect

    Montierth, B. S.

    1996-05-07

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two week payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual''s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.

  15. Emotion and Implicit Timing

    PubMed Central

    Droit-Volet, Sylvie

    2016-01-01

    This study examined the effects of emotion on implicit timing. In the implicit timing task used, the participants did not receive any temporal instructions. Instead they were simply asked and trained to press a key as quickly as possible after a stimulus (response stimulus) that was separated from a preceding stimulus by a given temporal interval (reference interval duration). However, in the testing phase, the interval duration was the reference interval duration or a shorter or longer interval duration. In addition, the participants attended two sessions: a first baseline session in which no stimulus was presented during the inter-stimulus intervals, and a second emotional session in which emotional facial expressions (angry, neutral and sad facial expressions) were presented during these intervals. Results showed faster RTs for interval durations close to the reference duration in both the baseline and the emotional conditions and yielded a U-shaped curve. This suggests that implicit processing of time persists in emotional contexts. In addition, the RT was faster for the facial expressions of anger than for those of neutrality and sadness. However, the U-shaped RT curve did not peak clearly at a shorter interval duration for the angry than for the other facial expressions. This lack of time distortion in an implicit timing task in response to arousing emotional stimuli questions the idea of an automatic speeding-up of the interval clock system involved in the representation of time. PMID:27380409

  16. Time-Distance Helioseismology

    NASA Technical Reports Server (NTRS)

    Duvall, Thomas L., Jr.

    2010-01-01

    Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

  17. Fossils, rocks, and time

    USGS Publications Warehouse

    Edwards, Lucy E.; Pojeta, John

    1999-01-01

    We study our Earth for many reasons: to find water to drink or oil to run our cars or coal to heat our homes, to know where to expect earthquakes or landslides or floods, and to try to understand our natural surroundings. Earth is constantly changing--nothing on its surface is truly permanent. Rocks that are now on top of a mountain may once have been at the bottom of the sea. Thus, to understand the world we live on, we must add the dimension of time. We must study Earth's history. When we talk about recorded history, time is measured in years, centuries, and tens of centuries. When we talk about Earth history, time is measured in millions and billions of years. Time is an everyday part of our lives. We keep track of time with a marvelous invention, the calendar, which is based on the movements of Earth in space. One spin of Earth on its axis is a day, and one trip around the Sun is a year. The modern calendar is a great achievement, developed over many thousands of years as theory and technology improved. People who study Earth's history also use a type of calendar, called the geologic time scale. It looks very different from the familiar calendar. In some ways, it is more like a book, and the rocks are its pages. Some of the pages are torn or missing, and the pages are not numbered, but geology gives us the tools to help us read this book.

  18. Fossils, rocks, and time

    USGS Publications Warehouse

    Edwards, Lucy E.; Pojeta, John, Jr.

    1993-01-01

    We study out Earth for many reasons: to find water to drink or oil to run our cars or coal to heat our homes, to know where to expect earthquakes or landslides or floods, and to try to understand our natural surroundings. Earth is constantly changing--nothing on its surface is truly permanent. Rocks that are not on top of a mountain may once have been on the bottom of the sea. Thus, to understand the world we live on, we must add the dimension of time. We must study Earth's history. When we talk about recorded history, time is measured in years, centuries, and tens of centuries. When we talk about Earth history, time is measured in millions and billions of years. Time is an everyday part of our lives. We keep track of time with a marvelous invention, the calendar, which is based on the movements of the Earth in space. One spin of Earth on its axis is a day, and one trip around the sun is a year. The modern calendar is a great achievement, developed over many thousands of years as theory and technology improved. People who study Earth's history also use a type of calendar, called the geologic time scale. It looks very different from the familiar calendar. In some ways, it is more like a book, and the rocks are its pages. Some of the pages are torn or missing, and the pages are not numbered, but geology gives us the tools to help us read this book.

  19. On Race and Time.

    PubMed

    Moskowitz, Gordon B; Olcaysoy Okten, Irmak; Gooch, Cynthia M

    2015-11-01

    Arousal is known to shape time perception, and heightened arousal causes one to perceive that time has slowed (i.e., a given length of time feels longer than it actually is). The current experiments illustrate that among White people who experience arousal when contemplating race (specifically those for whom appearing biased is an ongoing concern), time perception slows when they observe faces of Black men. We asked participants to judge the duration of presentation for faces of White and Black men (shown for periods ranging from 300 to 1,200 ms) relative to a standard duration of 600 ms. Evidence of bias emerged when White participants concerned with bias saw faces of Black men (e.g., durations of less than 600 ms were perceived as being greater than 600 ms). The current findings have implications for intergroup interactions in which timing is essential-for example, length of job interviews, police officers' perception of the length of an encounter and when force should be initiated, and doctors' perception of the length of medical encounters. Racially biased time perception is a new form of implicit bias, one exerted at the perceptual level. PMID:26423460

  20. Time dependent seismic hazard

    NASA Astrophysics Data System (ADS)

    Polidoro, B.; Iervolino, I.; Chioccarelli, E.; Giorgio, M.

    2012-04-01

    Probabilistic seismic hazard is usually computed trough a homogeneous Poisson process that even though it is a time-independent process it is widely used for its very convenient properties. However, when a single fault is of concern and/or the time scale is different from that of the long term, time-dependent processes are required. In this paper, different time-dependent models are reviewed with working examples. In fact, the Paganica fault (in central Italy) has been considered to compute both the probability of occurrence of at least one event in the lifespan of the structure, as well as the seismic hazard expressed in terms of probability of exceedance of an intensity value in a given time frame causing the collapse of the structure. Several models, well known or novel application to engineering hazard have been considered, limitation and issues in their applications are also discussed. The Brownian Passage Time (BPT) model is based on a stochastic modification of the deterministic stick-slip oscillator model for characteristic earthquakes; i.e., based on the addition of random perturbations (a Gaussian white noise) to the deterministic load path predicted by elastic rebound theory. This model assumes that the load state is at some ground level immediately after an event, increases steadly over time, reaches a failure threshold and relaxes instantaneously back to the ground level. For this model also a variable threshold has been considered to take into account the uncertainty of the threshold value. For the slip-predictable model it is assumed that the stress accumulates at a constant rate starting from some initial stress level. Stress is assumed to accumulate for a random period of time until an earthquake occurs. The size of the earthquake is governed by the stress release and it is a function of the elapsed time since the last event. In the time-predictable model stress buildup occurs at a constant rate until the accumulated stress reaches a threshold

  1. Time-domain imaging

    NASA Technical Reports Server (NTRS)

    Tolliver, C. L.

    1989-01-01

    The quest for the highest resolution microwave imaging and principle of time-domain imaging has been the primary motivation for recent developments in time-domain techniques. With the present technology, fast time varying signals can now be measured and recorded both in magnitude and in-phase. It has also enhanced our ability to extract relevant details concerning the scattering object. In the past, the interface of object geometry or shape for scattered signals has received substantial attention in radar technology. Various scattering theories were proposed to develop analytical solutions to this problem. Furthermore, the random inversion, frequency swept holography, and the synthetic radar imaging, have two things in common: (1) the physical optic far-field approximation, and (2) the utilization of channels as an extra physical dimension, were also advanced. Despite the inherent vectorial nature of electromagnetic waves, these scalar treatments have brought forth some promising results in practice with notable examples in subsurface and structure sounding. The development of time-domain techniques are studied through the theoretical aspects as well as experimental verification. The use of time-domain imaging for space robotic vision applications has been suggested.

  2. Time and moral judgment.

    PubMed

    Suter, Renata S; Hertwig, Ralph

    2011-06-01

    Do moral judgments hinge on the time available to render them? According to a recent dual-process model of moral judgment, moral dilemmas that engage emotional processes are likely to result in fast deontological gut reactions. In contrast, consequentialist responses that tot up lives saved and lost in response to such dilemmas would require cognitive control to override the initial response. Cognitive control, however, takes time. In two experiments, we manipulated the time available to arrive at moral judgments in two ways: by allotting a fixed short or large amount of time, and by nudging people to answer swiftly or to deliberate thoroughly. We found that faster responses indeed lead to more deontological responses among those moral dilemmas in which the killing of one to save many necessitates manhandling an innocent person and in which this action is depicted as a means to an end. Thus, our results are the first demonstration that inhibiting cognitive control through manipulations of time alters moral judgments. PMID:21354557

  3. Discrete-Time Goldfishing

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco

    2011-08-01

    The original continuous-time ''goldfish'' dynamical system is characterized by two neat formulas, the first of which provides the N Newtonian equations of motion of this dynamical system, while the second provides the solution of the corresponding initial-value problem. Several other, more general, solvable dynamical systems ''of goldfish type'' have been identified over time, featuring, in the right-hand (''forces'') side of their Newtonian equations of motion, in addition to other contributions, a velocity-dependent term such as that appearing in the right-hand side of the first formula mentioned above. The solvable character of these models allows detailed analyses of their behavior, which in some cases is quite remarkable (for instance isochronous or asymptotically isochronous). In this paper we introduce and discuss various discrete-time dynamical systems, which are as well solvable, which also display interesting behaviors (including isochrony and asymptotic isochrony) and which reduce to dynamical systems of goldfish type in the limit when the discrete-time independent variable l=0,1,2,... becomes the standard continuous-time independent variable t, 0≤t<∞.

  4. Accurate measurement of time

    NASA Astrophysics Data System (ADS)

    Itano, Wayne M.; Ramsey, Norman F.

    1993-07-01

    The paper discusses current methods for accurate measurements of time by conventional atomic clocks, with particular attention given to the principles of operation of atomic-beam frequency standards, atomic hydrogen masers, and atomic fountain and to the potential use of strings of trapped mercury ions as a time device more stable than conventional atomic clocks. The areas of application of the ultraprecise and ultrastable time-measuring devices that tax the capacity of modern atomic clocks include radio astronomy and tests of relativity. The paper also discusses practical applications of ultraprecise clocks, such as navigation of space vehicles and pinpointing the exact position of ships and other objects on earth using the GPS.

  5. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  6. Time rate collision matrix

    SciTech Connect

    Stoenescu, M.L.; Smith, T.M.

    1980-02-01

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations.

  7. Agency, time, and causality

    PubMed Central

    Widlok, Thomas

    2014-01-01

    Cognitive Scientists interested in causal cognition increasingly search for evidence from non-Western Educational Industrial Rich Democratic people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition. PMID:25414683

  8. Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Coryphaeus Software, founded in 1989 by former NASA electronic engineer Steve Lakowske, creates real-time 3D software. Designer's Workbench, the company flagship product, is a modeling and simulation tool for the development of both static and dynamic 3D databases. Other products soon followed. Activation, specifically designed for game developers, allows developers to play and test the 3D games before they commit to a target platform. Game publishers can shorten development time and prove the "playability" of the title, maximizing their chances of introducing a smash hit. Another product, EasyT, lets users create massive, realistic representation of Earth terrains that can be viewed and traversed in real time. Finally, EasyScene software control the actions among interactive objects within a virtual world. Coryphaeus products are used on Silican Graphics workstation and supercomputers to simulate real-world performance in synthetic environments. Customers include aerospace, aviation, architectural and engineering firms, game developers, and the entertainment industry.

  9. Timing is everything

    PubMed Central

    Faulk, Christopher

    2011-01-01

    Environmental influence on developmental plasticity impacts a wide diversity of animal life from insects to humans. We now understand the epigenetic basis for many of these altered phenotypes. The five environmental factors of nutrition, behavior, stress, toxins and stochasticity work individually and in concert to affect the developing epigenome. During early embryogenesis, epigenetic marks, such as DNA methylation, are reset at specific times. Two waves of global demethylation and reestablishment of methylation frame the sensitive times for early environmental influences and will be the focus of this review. Gene transcription, translation and post-translational modification of chromatin remodeling complexes are three mechanisms affected by developmental exposure to environmental factors. To illustrate how changes in the early environment profoundly affect these mechanisms, we provide examples throughout the animal kingdom. Herein we review the history, time points and mechanisms of epigenetic gene-environment interaction. PMID:21636976

  10. Times for interplanetary trips

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    The times required to travel to the various planets at an acceleration of one g are calculated. Surrounding gravitational fields are neglected except for a relatively short distance near take-off or landing. The orbit consists of an essentially straight line with the thrust directed toward the destination up to the halfway point, but in the opposite direction for the remainder so that the velocity is zero on arrival. A table lists the approximate times required, and also the maximum velocities acquired in light units v/c for the various planets.

  11. Time, Chance, and Reduction

    NASA Astrophysics Data System (ADS)

    Ernst, Gerhard; Hüttemann, Andreas

    2010-01-01

    List of contributors; 1. Introduction Gerhard Ernst and Andreas Hütteman; Part I. The Arrows of Time: 2. Does a low-entropy constraint prevent us from influencing the past? Mathias Frisch; 3. The part hypothesis meets gravity Craig Callender; 4. Quantum gravity and the arrow of time Claus Kiefer; Part II. Probability and Chance: 5. The natural-range conception of probability Jacob Rosenthal; 6. Probability in Boltzmannian statistical mechanics Roman Frigg; 7. Humean mechanics versus a metaphysics of powers Michael Esfeld; Part III. Reduction: 8. The crystallisation of Clausius's phenomenological thermodynamics C. Ulises Moulines; 9. Reduction and renormalization Robert W. Batterman; 10. Irreversibility in stochastic dynamics Jos Uffink; Index.

  12. Laboratory Turnaround Time

    PubMed Central

    Hawkins, Robert C

    2007-01-01

    Turnaround time (TAT) is one of the most noticeable signs of laboratory service and is often used as a key performance indicator of laboratory performance. This review summarises the literature regarding laboratory TAT, focusing on the different definitions, measures, expectations, published data, associations with clinical outcomes and approaches to improve TAT. It aims to provide a consolidated source of benchmarking data useful to the laboratory in setting TAT goals and to encourage introduction of TAT monitoring for continuous quality improvement. A 90% completion time (sample registration to result reporting) of <60 minutes for common laboratory tests is suggested as an initial goal for acceptable TAT. PMID:18392122

  13. VSX2 and ASCL1 Are Indicators of Neurogenic Competence in Human Retinal Progenitor Cultures.

    PubMed

    Wright, Lynda S; Pinilla, Isabel; Saha, Jishnu; Clermont, Joshua M; Lien, Jessica S; Borys, Katarzyna D; Capowski, Elizabeth E; Phillips, M Joseph; Gamm, David M

    2015-01-01

    Three dimensional (3D) culture techniques are frequently used for CNS tissue modeling and organoid production, including generation of retina-like tissues. A proposed advantage of these 3D systems is their potential to more closely approximate in vivo cellular microenvironments, which could translate into improved manufacture and/or maintenance of neuronal populations. Visual System Homeobox 2 (VSX2) labels all multipotent retinal progenitor cells (RPCs) and is known to play important roles in retinal development. In contrast, the proneural transcription factor Acheate scute-like 1 (ASCL1) is expressed transiently in a subset of RPCs, but is required for the production of most retinal neurons. Therefore, we asked whether the presence of VSX2 and ASCL1 could gauge neurogenic potential in 3D retinal cultures derived from human prenatal tissue or ES cells (hESCs). Short term prenatal 3D retinal cultures displayed multiple characteristics of human RPCs (hRPCs) found in situ, including robust expression of VSX2. Upon initiation of hRPC differentiation, there was a small increase in co-labeling of VSX2+ cells with ASCL1, along with a modest increase in the number of PKCα+ neurons. However, 3D prenatal retinal cultures lost expression of VSX2 and ASCL1 over time while concurrently becoming refractory to neuronal differentiation. Conversely, 3D optic vesicles derived from hESCs (hESC-OVs) maintained a robust VSX2+ hRPC population that could spontaneously co-express ASCL1 and generate photoreceptors and other retinal neurons for an extended period of time. These results show that VSX2 and ASCL1 can serve as markers for neurogenic potential in cultured hRPCs. Furthermore, unlike hESC-OVs, maintenance of 3D structure does not independently convey an advantage in the culture of prenatal hRPCs, further illustrating differences in the survival and differentiation requirements of hRPCs extracted from native tissue vs. those generated entirely in vitro. PMID:26292211

  14. Time reversal communication system

    DOEpatents

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  15. Timing and throttle linkage

    SciTech Connect

    Wenstadt, T.D.; Hagen, M.W.

    1986-11-18

    This patent describes a timing throttle control for a spark ignition internal combustion engine having a fuel/air mixing device and a spark timing device. The control comprises a first pivot on the engine, a first lever mounted on the pivot and including a cam slot having a first portion which has a substantially uniform radius about the pivot and a second portion which has a non-constant radii about the first pivot. A control means is connected to the first lever to actuate the first lever about the first pivot, a second pivot on the engine in non-parallel relation to the first pivot. A second lever is mounted on the second pivot and operative to control the timing of the spark timing device, a spherical cam follower is mounted on the second lever and engaged with the cam slot. A third lever is mounted on the third pivot and operatively connected to the fuel/air mixing device. A link interconnects the first level and the third lever.

  16. Time on Your Side.

    ERIC Educational Resources Information Center

    Webber, Ross Arkell

    1989-01-01

    Six ways for development officers to handle overload are identified: distinguish between urgency and importance; selectively ignore time demands; focus on where to make the greatest contribution; delegate tasks; tend interpersonal relationships; and make progress on critical long-term objectives. (MLW)

  17. "Time" in China.

    ERIC Educational Resources Information Center

    Weland, James E.

    1982-01-01

    Discusses how the Chinese have recorded their history by dynasties, the length of time any one imperial clan could retain its hold on the Dragon Throne. Dynastic histories were used to instruct rulers in the ways ethical problems of government had been dealt with in the past. (AM)

  18. Screen time and children

    MedlinePlus

    ... screen, such as watching TV, working on a computer, or playing video games. Screen time is sedentary activity, meaning you are ... child eat while watching TV or using the computer. DO NOT leave the ... as family board games, puzzles, or going for a walk. Keep a ...

  19. Time-Encoded Imagers.

    SciTech Connect

    Marleau, Peter; Brubaker, Erik

    2014-11-01

    This report provides a short overview of the DNN R&D funded project, Time-Encoded Imagers. The project began in FY11 and concluded in FY14. The Project Description below provides the overall motivation and objectives for the project as well as a summary of programmatic direction. It is followed by a short description of each task and the resulting deliverables.

  20. Saving Time with Technology

    ERIC Educational Resources Information Center

    Gullen, Kristine; Zimmerman, Holly

    2013-01-01

    In order to help teachers envision digital products in action in classrooms, the authors look at three examples of how teachers they know enhance learning time by employing technology efficiently. The examples include: (1) a social studies teacher who begins each class period with a three-question formative assessment using the website…

  1. Video Time Encoding Machines

    PubMed Central

    Lazar, Aurel A.; Pnevmatikakis, Eftychios A.

    2013-01-01

    We investigate architectures for time encoding and time decoding of visual stimuli such as natural and synthetic video streams (movies, animation). The architecture for time encoding is akin to models of the early visual system. It consists of a bank of filters in cascade with single-input multi-output neural circuits. Neuron firing is based on either a threshold-and-fire or an integrate-and-fire spiking mechanism with feedback. We show that analog information is represented by the neural circuits as projections on a set of band-limited functions determined by the spike sequence. Under Nyquist-type and frame conditions, the encoded signal can be recovered from these projections with arbitrary precision. For the video time encoding machine architecture, we demonstrate that band-limited video streams of finite energy can be faithfully recovered from the spike trains and provide a stable algorithm for perfect recovery. The key condition for recovery calls for the number of neurons in the population to be above a threshold value. PMID:21296708

  2. The Time Has Come.

    ERIC Educational Resources Information Center

    Maxwell, John C.

    The report by the National Assessment of Educational Progress entitled "Poor Writing Performance Blamed on Scant Writing Practice" makes it clear that little progress has been made in the improvement of students' writing. This is true in part because the conditions for teaching writing are unsatisfatory. The time has come to undertake a major…

  3. Leadership in Challenging Times

    ERIC Educational Resources Information Center

    City, Elizabeth A.

    2013-01-01

    In spite of tough financial times, resourceful school leaders devise ways to overcome challenges and improve education. To do this, they make strategic use of the resources they have. And they also cultivate learning communities. In this article, Elizabeth A. City describes how school leaders can make more strategic use of three essential…

  4. Decay Time of Cathodoluminescence

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2009-01-01

    Simple measurements of the decay time of cathodoluminescence are described. Cathodoluminescence is used in many devices, including computer monitors, oscilloscopes, radar displays and television tubes. The experimental setup is simple and easy to build. Two oscilloscopes, a function generator, and a fast photodiode are needed for the experiments.…

  5. Time for Reading?

    ERIC Educational Resources Information Center

    Fowler, William R.

    1989-01-01

    Reading for pleasure and enlightenment is a critical, and endangered, element in a well-informed citizenry. As a basis for intellectual growth, reading is threatened by media misuse and lack of encouragement of recreational reading. Solutions include emphasis on integrated skills, improved time allocation, and cooperation among parents, teachers,…

  6. Time Dependent Fluids

    ERIC Educational Resources Information Center

    Collyer, A. A.

    1974-01-01

    Discusses the flow characteristics of thixotropic and negative thixotropic fluids; various theories underlying the thixotropic behavior; and thixotropic phenomena exhibited in drilling muds, commercial paints, pastes, and greases. Inconsistencies in the terminology used to label time dependent effects are revealed. (CC)

  7. Part-Time Employment.

    ERIC Educational Resources Information Center

    Guichard, Gus; And Others

    The employment of community college instructors on a part-time basis provides the opportunity for students to study under outstanding instructors whose primary employment may be in industry or in other postsecondary institutions and permits colleges to respond better to community needs with the financial resources available to them. Along with…

  8. HAWC Timing Calibration

    NASA Astrophysics Data System (ADS)

    Kelley-Hoskins, Nathan; Huentemeyer, Petra; Matthews, John; Dingus, Brenda; HAWC Collaboration

    2011-04-01

    The High-Altitude Water Cherenkov (HAWC) Experiment is a second-generation high sensitivity gamma-ray and cosmic-ray detector that builds on the experience and technology of the Milagro observatory. HAWC utilizes the water Cherenkov technique to measure extensive air showers. Instead of a pond filled with water (as in Milagro), an array of closely packed water tanks with 3 PMTs each is used. The cosmic ray's direction will be reconstructed using the times when the PMTs in each tank are triggered. Therefore, the timing calibration will be crucial for reaching an angular resolution as low as 0.1 degrees. We propose to use a laser calibration system, patterned after the calibration system in Milagro. The HAWC optical calibration system uses less than 1 ns laser light pulses, directed into two optical fiber networks. Each network will use optical fan-outs and switches to direct light to specific tanks. The first network is used to measure the light transit time out to each pair of tanks, and the second network sends light to each tank, calibrating each tank's 3 PMTs. Time slewing corrections will be made using neutral density filters to control the light intensity over 4 orders of magnitude. This system is envisioned to run both continuously at a low rate, or at a high rate with many intensity levels. In this presentation, we present the design of the calibration system and first measurements of its performance.

  9. Take time for laughter.

    PubMed

    Huntley, Mary I

    2009-01-01

    Taking time for positive laughter in the workplace every day is energizing, health-promoting, and rewarding. Humor happenings and mirthful moments are all around us; we need to be receptive to them. Research provides evidence that laughter is a powerful tool when used appropriately in our personal and professional life journey. PMID:19343850

  10. Time Series Database

    Energy Science and Technology Software Center (ESTSC)

    2007-11-02

    TSDB is a Python module for storing large volumes of time series data. TSDB stores data in binary files indexed by a timestamp. Aggregation functions (such as rate, sum, avg, etc.) can be performed on the data, but data is never discarded. TSDB is presently best suited for SNMP data but new data types are easily added.

  11. A Moment in Time

    ERIC Educational Resources Information Center

    Lonergan, David

    2013-01-01

    There is a growing literature on the disappearance of the traditional model of higher education. Fewer courses are taught now than was the case just a few years ago by a full-time, permanent instructor in a single location, to students that the instructor has actually met in person. Another very real threat to the range of education is the growing…

  12. Asymmetry through time dependency

    NASA Astrophysics Data System (ADS)

    Mantzaris, Alexander V.; Higham, Desmond J.

    2016-03-01

    Given a single network of interactions, asymmetry arises when the links are directed. For example, if protein A upregulates protein B and protein B upregulates protein C, then (in the absence of any further relationships between them) A may affect C but not vice versa. This type of imbalance is reflected in the associated adjacency matrix, which will lack symmetry. A different type of imbalance can arise when interactions appear and disappear over time. If A meets B today and B meets C tomorrow, then (in the absence of any further relationships between them) A may pass a message or disease to C, but not vice versa. Hence, even when each interaction is a two-way exchange, the effect of time ordering can introduce asymmetry. This observation is very closely related to the fact that matrix multiplication is not commutative. In this work, we describe a method that has been designed to reveal asymmetry in static networks and show how it may be combined with a measure that summarizes the potential information flow between nodes in the temporal case. This results in a new method that quantifies the asymmetry arising through time ordering. We show by example that the new tool can be used to visualize and quantify the amount of asymmetry caused by the arrow of time.

  13. The SIM Time Network.

    PubMed

    Lombardi, Michael A; Novick, Andrew N; Lopez R, J Mauricio; Jimenez, Francisco; de Carlos Lopez, Eduardo; Boulanger, Jean-Simon; Pelletier, Raymond; de Carvalho, Ricardo J; Solis, Raul; Sanchez, Harold; Quevedo, Carlos Andres; Pascoe, Gregory; Perez, Daniel; Bances, Eduardo; Trigo, Leonardo; Masi, Victor; Postigo, Henry; Questelles, Anthony; Gittens, Anselm

    2011-01-01

    The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization (RMO) whose members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS). The SIM/OAS region extends throughout North, Central, and South America and the Caribbean Islands. About half of the SIM NMIs maintain national standards of time and frequency and must participate in international comparisons in order to establish metrological traceability to the International System (SI) of units. The SIM time network (SIMTN) was developed as a practical, cost effective, and technically sound way to automate these comparisons. The SIMTN continuously compares the time standards of SIM NMIs and produces measurement results in near real-time by utilizing the Internet and the Global Positioning System (GPS). Fifteen SIM NMIs have joined the network as of December 2010. This paper provides a brief overview of SIM and a technical description of the SIMTN. It presents international comparison results and examines the measurement uncertainties. It also discusses the metrological benefits that the network provides to its participants. PMID:26989584

  14. Bootstrapping Time Dilation Decoherence

    NASA Astrophysics Data System (ADS)

    Gooding, Cisco; Unruh, William G.

    2015-10-01

    We present a general relativistic model of a spherical shell of matter with a perfect fluid on its surface coupled to an internal oscillator, which generalizes a model recently introduced by the authors to construct a self-gravitating interferometer (Gooding and Unruh in Phys Rev D 90:044071, 2014). The internal oscillator evolution is defined with respect to the local proper time of the shell, allowing the oscillator to serve as a local clock that ticks differently depending on the shell's position and momentum. A Hamiltonian reduction is performed on the system, and an approximate quantum description is given to the reduced phase space. If we focus only on the external dynamics, we must trace out the clock degree of freedom, and this results in a form of intrinsic decoherence that shares some features with a proposed "universal" decoherence mechanism attributed to gravitational time dilation (Pikovski et al in Nat Phys, 2015). We note that the proposed decoherence remains present in the (gravity-free) limit of flat spacetime, emphasizing that the effect can be attributed entirely to proper time differences, and thus is not necessarily related to gravity. Whereas the effect described in (Pikovski et al in Nat Phys, 2015) vanishes in the absence of an external gravitational field, our approach bootstraps the gravitational contribution to the time dilation decoherence by including self-interaction, yielding a fundamentally gravitational intrinsic decoherence effect.

  15. In Time of War.

    ERIC Educational Resources Information Center

    Becker, Patti Clayton

    2003-01-01

    Examines the role of libraries, particularly public libraries, in times of war. Discusses similarities between responses after World War Two and the September 11, 2001 attacks; government restrictions on information; American Library Association responses, including propaganda and libraries; and the library and the community. (LRW)

  16. Time for School?

    ERIC Educational Resources Information Center

    Marcotte, Dave E.; Hansen, Benjamin

    2010-01-01

    Students in the United States spend much less time in school than do students in most other industrialized nations, and the school year has been essentially unchanged for more than a century. This is not to say that there is no interest in extending the school year. While there has been little solid evidence that doing so will improve learning…

  17. Where in Time?

    ERIC Educational Resources Information Center

    Pecore, John; Sacks, David

    2005-01-01

    In this article, the authors describe an activity developed to assist students with constructing their own understanding of Earth's history and provide questions to help teach the geologic time scale. The lesson is aligned to the following National Science Education Standards: Science as Inquiry, Earth's History, and Nature of Science. While…

  18. A Walk through Time.

    ERIC Educational Resources Information Center

    Renfroe, Mark; Letendre, Wanda

    1996-01-01

    Describes a seventh-grade class project where students constructed a "time tunnel" (a walk-through display with models and exhibits illustrating various themes and eras). Beginning modestly, the tunnel grew over seven years to include 11 different display scenes. Discusses the construction of the project and benefits to the school. (MJP)

  19. Time and Moral Judgment

    ERIC Educational Resources Information Center

    Suter, Renata S.; Hertwig, Ralph

    2011-01-01

    Do moral judgments hinge on the time available to render them? According to a recent dual-process model of moral judgment, moral dilemmas that engage emotional processes are likely to result in fast deontological gut reactions. In contrast, consequentialist responses that tot up lives saved and lost in response to such dilemmas would require…

  20. This Time It's Personal

    ERIC Educational Resources Information Center

    Demski, Jennifer

    2012-01-01

    Educators have known for some time now that a one-size-fits-all approach to learning does not lead to the level of student engagement and academic success that schools strive to achieve. In their search for a more customized approach to delivering instruction, they've explored project-based learning, addressed different learning styles, and…

  1. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  2. It's Time to Reassess.

    ERIC Educational Resources Information Center

    Van Groningen, Tom

    In light of recent changes in social and cultural values and the effects these changes have had on higher education, community college leaders must take the time to reassess the mission and function of the California community colleges. Shifts away from traditional values toward an increased emphasis on personal needs and aspirations may explain…

  3. Time in perspective.

    PubMed

    Gorea, Andrei; Hau, Janice

    2013-08-01

    Perceptions of time and space are subject to strong contextual effects. Like their physical counterparts, they appear to be bound together. The perceived spatial extent of a constant retinal extent increases with its perceived distance from the observer. The perceived duration of a moving object increases with its covered angular trajectory. It follows that the perceived duration of moving objects covering identical angular trajectories should also increase with distance. Using three-dimensionally rendered balls rolling for 600 ms, 900 ms, and 1,200 ms and covering 5.5°, 11°, and 22° trajectories in fronto-parallel planes of a linear-perspective scene, we showed that perceived duration dilates by up to 50% as the fronto-parallel plane of the rolling ball recedes from the observer. Such time dilation is mostly contributed to by the smaller size of the distant ball. As in a three-dimensional world, objects' sizes and their covered trajectories per time unit decrease with distance, and as the two factors lead to opposite perceived-duration effects, the results suggest a form of time constancy in a three-dimensional world. PMID:23774463

  4. On Space and Time

    NASA Astrophysics Data System (ADS)

    Majid, Shahn; Polkinghorne, With contributions by John; Penrose, Roger; Taylor, Andrew; Connes, Alain; Heller, Michael

    2012-03-01

    Preface; 1. The dark universe A. N. Taylor; 2. Quantum spacetime and physical reality S. Majid; 3. Causality, quantum theory and cosmology R. Penrose; 4. On the fine structure of spacetime A. Connes; 5. Where physics meets metaphysics M. Heller; 6. The nature of time J. C. Polkinghorne; Index.

  5. On Space and Time

    NASA Astrophysics Data System (ADS)

    Majid, Shahn; Connes, With contributions by Alain; Heller, Michael; Penrose, Roger; Polkinghorne, John; Taylor, Andrew

    2008-09-01

    Preface; 1. The dark universe A. N. Taylor; 2. Quantum spacetime and physical reality S. Majid; 3. Causality, quantum theory and cosmology R. Penrose; 4. On the fine structure of spacetime A. Connes; 5. Where physics meets metaphysics M. Heller; 6. The nature of time J. C. Polkinghorne; Index.

  6. The SIM Time Network

    PubMed Central

    Lombardi, Michael A.; Novick, Andrew N.; Lopez R, J. Mauricio; Jimenez, Francisco; de Carlos Lopez, Eduardo; Boulanger, Jean-Simon; Pelletier, Raymond; de Carvalho, Ricardo J.; Solis, Raul; Sanchez, Harold; Quevedo, Carlos Andres; Pascoe, Gregory; Perez, Daniel; Bances, Eduardo; Trigo, Leonardo; Masi, Victor; Postigo, Henry; Questelles, Anthony; Gittens, Anselm

    2011-01-01

    The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization (RMO) whose members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS). The SIM/OAS region extends throughout North, Central, and South America and the Caribbean Islands. About half of the SIM NMIs maintain national standards of time and frequency and must participate in international comparisons in order to establish metrological traceability to the International System (SI) of units. The SIM time network (SIMTN) was developed as a practical, cost effective, and technically sound way to automate these comparisons. The SIMTN continuously compares the time standards of SIM NMIs and produces measurement results in near real-time by utilizing the Internet and the Global Positioning System (GPS). Fifteen SIM NMIs have joined the network as of December 2010. This paper provides a brief overview of SIM and a technical description of the SIMTN. It presents international comparison results and examines the measurement uncertainties. It also discusses the metrological benefits that the network provides to its participants. PMID:26989584

  7. Lessons: Math. It's Time.

    ERIC Educational Resources Information Center

    Krech, Bob

    2000-01-01

    Describes how to use a one-handed clock for teaching time telling: make a one-handed clock (hour hand only); discuss clock history; have students use approximate language to describe where the hour hand is; have students practice with their own clocks; introduce the minute hand; have students compare the clocks; and have students add minute hands…

  8. Geologic time scale bookmark

    USGS Publications Warehouse

    U.S. Geological Survey

    2012-01-01

    This bookmark, designed for use with U.S. Geological Survey activities at the 2nd USA Science and Engineering Festival (April 26–29, 2012), is adapted from the more detailed Fact Sheet 2010–3059 "Divisions of Geologic Time." The information that it presents is widely sought by educators and students.

  9. The First Time

    ERIC Educational Resources Information Center

    Black, Beth

    2011-01-01

    In this article, the author narrates her experience of meeting a Montessori kid for the first time and shares the characteristics she observed in Montessori students. The author was working as director of academic resources in university housing at the University of Wisconsin-Madison and met Jason, a pre-med sophomore who was the resident…

  10. Equal Time for Women.

    ERIC Educational Resources Information Center

    Kolata, Gina

    1984-01-01

    Examines social influences which discourage women from pursuing studies in computer science, including monopoly of computer time by boys at the high school level, sexual harassment in college, movies, and computer games. Describes some initial efforts to encourage females of all ages to study computer science. (JM)

  11. Stop wasting valuable time.

    PubMed

    Mankins, Michael C

    2004-09-01

    Companies routinely squander their most precious resource--the time of their top executives. In the typical company, senior executives meet to discuss strategy for only three hours a month. And that time is poorly spent in diffuse discussions never even meant to result in any decision. The price of misused executive time is high. Delayed strategic decisions lead to overlooked waste and high costs, harmful cost reductions, missed new product and business development opportunities, and poor long-term investments. But a few deceptively simple changes in the way top management teams set agendas and structure team meetings can make an enormous difference in their effectiveness. Efficient companies use seven techniques to make the most of the time their top executives spend together. They keep strategy meetings separate from meetings focused on operations. They explore issues through written communications before they meet, so that meeting time is used solely for reaching decisions. In setting agendas, they rank the importance of each item according to its potential to create value for the company. They seek to get issues not only on, but also off, the agenda quickly, keeping to a clear implementation timetable. They make sure they have considered all viable alternatives before deciding a course of action. They use a common language and methodology for reaching decisions. And they insist that, once a decision is made, they stick to it--that there be no more debate or mere grudging compliance. Once leadership teams get the basics right, they can make more fundamental changes in the way they work together. Strategy making can be transformed from a series of fragmented and unproductive events into a streamlined, effective, and continuing management dialogue. In companies that have done this, management meetings aren't a necessary evil; they're a source of real competitive advantage. PMID:15449855

  12. Time and Learning. ERIC Digest.

    ERIC Educational Resources Information Center

    Metzker, Bill

    The use of time in school is undergoing close scrutiny. Over the years, educators have sought to enhance learning time through such reforms as block scheduling and year-round schools. School time can be conceived as an inverted pyramid, in which allocated time (total time in the school day or year) forms the top tier, engaged time (time-on-task)…

  13. Dielectric relaxation time spectroscopy.

    PubMed

    Paulson, K S; Jouravleva, S; McLeod, C N

    2000-11-01

    A new mathematical method is developed to recover the permittivity relaxation spectrum of living tissue from measurements of the real and imaginary parts of the impedance. Aiming to derive information about electrical properties of living tissue without the prior selection of any impedance model, the procedure calculates the relaxation time distribution. It provides new characteristic independent parameters: time constants, their distribution, and the amplitudes of the associated dispersion. As the beta-dispersion is the most important in the area of electrical impedance spectroscopy of tissue, the paper gives an estimate of the essential frequency range to cover the whole relaxation spectrum in that area. Results are presented from both simulation and known lumped--constant element circuit. PMID:11077745

  14. Timing is Everything

    SciTech Connect

    Wiley, H. S.

    2009-08-01

    You want to be ahead of the curve, but not so far ahead that no one can see you. Historically, the scientific community has tended to ignore science that is too innovative or ahead of its time. For this, we are often accused of being biased towards maintaining some fictional status quo. The reason these papers often get forgotten, however, has more to do with the usability of innovative ideas, rather than some perverseness. The classic case is Mendel, whose pioneering ideas on inheritance were ignored for many years. It wasn’t because the scientific community did not know about him; Mendel simply addressed different questions than other scientists at the time. Years later, when chromosomes were identified as a potential mechanism for transmitting genetic information, his ideas suddenly became relevant to a much wider scientific audience.

  15. Applying for Time

    NASA Astrophysics Data System (ADS)

    Lennon, D.

    2005-03-01

    Over the years the instrument suite at the WHT has changed many times. One constant in all these changes is that our intermediate dispersion spectrograph ISIS continues to win the largest share of the observing time across all our three TACs. It's therefore good to see some improvements coming to this venerable instrument. The past 6 months have seen the commissioning of a new dichroic beam splitter, and initial tests indicate that the infamous ripples which plagued the old dichroic set are substantially reduced. Throughput in both blue and red arms is improved, while the response of the new blue fold mirror is also substantially better than before. This is the only dichroic which will be offered in service mode, and will be the default dichroic offered to visiting observers unless an alternative is specified. It is expected that the older dichroics will be phased out of use pending feedback from users.

  16. Researching participant recruitment times.

    PubMed

    O'Brien, Rachel; Black, Polly

    2015-11-01

    Conducting research in emergency departments is relatively new, and there are a number of ethical and practical challenges to recruiting patients in these settings. In 2008, the Emergency Medicine Research Group Edinburgh (EMERGE) was set up at the Royal Infirmary of Edinburgh emergency department to support researchers and encourage the growth of research in emergency medicine. As part of a review of their working methods, the group's clinical nurse researchers undertook a small study to identify participant recruitment times. The results showed a significant difference between perceived and actual recruitment times, which has implications for planning staff numbers and budgets. This article describes the evaluation process and methods of data collection, and discusses the results. PMID:26542924

  17. Hard Times Hit Schools

    ERIC Educational Resources Information Center

    McNeil, Michele

    2008-01-01

    Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

  18. Music in Galileo's Time

    NASA Astrophysics Data System (ADS)

    Petrobelli, P.

    2011-06-01

    Claudio Monteverdi appears as the key personality of the music in Galileo's time. His revolution in format and function of the musical language-from an essentially edonistic creation of purely sonorous images to a musical language consciously "expressive" of the content of the words on which it is based-is similar in character to the influential innovations in scientific thinking operated by Galileo.

  19. Making time to talk.

    PubMed

    2016-09-01

    NHS Employers has updated its people performance management toolkit, which now includes links to new guidance and resources. The toolkit encourages managers to 'make time to talk' about performance with staff, provides practical support, increases managers' knowledge about what good performance management is, and aims to increase their confidence in dealing with associated challenges, such as what to do if a team member is underperforming and how to give constructive feedback. PMID:27581903

  20. Time at the beginning

    SciTech Connect

    Michael S. Turner

    2002-10-11

    Age consistency for the Universe today has been an important cosmological test. Even more powerful consistency tests at times as early as 10{sup -32} sec lie ahead in the precision era of cosmology. I outline tests based upon cosmic microwave background (CMB) anisotropy, big-bang nucleosynthesis (BBN), particle dark matter, phase transitions, and inflation. The ultimate cosmic timescale--the fate of the Universe--will be in doubt until the mystery of the dark energy is unraveled.

  1. Real Time Baseball Database

    NASA Astrophysics Data System (ADS)

    Fukue, Yasuhiro

    The author describes the system outline, features and operations of "Nikkan Sports Realtime Basaball Database" which was developed and operated by Nikkan Sports Shimbun, K. K. The system enables to input numerical data of professional baseball games as they proceed simultaneously, and execute data updating at realtime, just-in-time. Other than serving as supporting tool for prepareing newspapers it is also available for broadcasting media, general users through NTT dial Q2 and others.

  2. Tevatron injection timing

    SciTech Connect

    Saritepe, S.; Annala, G.

    1993-06-01

    Bunched beam transfer from one accelerator to another requires coordination and synchronization of many ramped devices. During collider operation timing issues are more complicated since one has to switch from proton injection devices to antiproton injection devices. Proton and antiproton transfers are clearly distinct sequences since protons and antiprotons circulate in opposite directions in the Main Ring (MR) and in the Tevatron. The time bumps are different, the kicker firing delays are different, the kickers and lambertson magnets are different, etc. Antiprotons are too precious to be used for tuning purposes, therefore protons are transferred from the Tevatron back into the Main Ring, tracing the path of antiprotons backwards. This tuning operation is called ``reverse injection.`` Previously, the reverse injection was handled in one supercycle. One batch of uncoalesced bunches was injected into the Tevatron and ejected after 40 seconds. Then the orbit closure was performed in the MR. In the new scheme the lambertson magnets have to be moved and separator polarities have to be switched, activities that cannot be completed in one supercycle. Therefore, the reverse injection sequence was changed. This involved the redefinition of TVBS clock event $D8 as MRBS $D8 thus making it possible to inject 6 proton batches (or coalesced bunches) and eject them one at a time on command, performing orbit closure each time in the MR. Injection devices are clock event driven. The TCLK is used as the reference clock. Certain TCLK events are triggered by the MR beam synchronized clock (MRBS) events. Some delays are measured in terms of MRBS ticks and MR revolutions. See Appendix A for a brief description of the beam synchronized clocks.

  3. Time dependent holography

    NASA Astrophysics Data System (ADS)

    Das, Diptarka

    One of the most important results emerging from string theory is the gauge gravity duality (AdS/CFT correspondence) which tells us that certain problems in particular gravitational backgrounds can be exactly mapped to a particular dual gauge theory a quantum theory very similar to the one explaining the interactions between fundamental subatomic particles. The chief merit of the duality is that a difficult problem in one theory can be mapped to a simpler and solvable problem in the other theory. The duality can be used both ways. Most of the current theoretical framework is suited to study equilibrium systems, or systems where time dependence is at most adiabatic. However in the real world, systems are almost always out of equilibrium. Generically these scenarios are described by quenches, where a parameter of the theory is made time dependent. In this dissertation I describe some of the work done in the context of studying quantum quench using the AdS/CFT correspondence. We recover certain universal scaling type of behavior as the quenching is done through a quantum critical point. Another question that has been explored in the dissertation is time dependence of the gravity theory. Present cosmological observations indicate that our universe is accelerating and is described by a spacetime called de-Sitter(dS). In 2011 there had been a speculation over a possible duality between de-Sitter gravity and a particular field theory (Euclidean SP(N) CFT). However a concrete realization of this proposition was still lacking. Here we explicitly derive the dS/CFT duality using well known methods in field theory. We discovered that the time dimension emerges naturally in the derivation. We also describe further applications and extensions of dS/CFT. KEYWORDS: Holography, AdS/CFT correspondence, Quantum Quench, dS/CFT correspondence, Chaos.

  4. Running out of time.

    PubMed

    Zigmond, Jessica

    2013-10-21

    After a glitch-plagued rollout of state and federal healthcare exchanges, officials are scrambling to fix the marketplaces before a crucial mid-November deadline. If the problems can't be fixed in time for consumers to get enrolled by Jan. 1, it will hand ammunition to Republicans who want to delay the ACA's individual mandate. "If you can't enroll people, how can you penalize them?" asks Tom Miller of the American Enterprise Institute. PMID:24340853

  5. Pulse Portraiture: Pulsar timing

    NASA Astrophysics Data System (ADS)

    Pennucci, Timothy T.; Demorest, Paul B.; Ransom, Scott M.

    2016-06-01

    Pulse Portraiture is a wideband pulsar timing code written in python. It uses an extension of the FFTFIT algorithm (Taylor 1992) to simultaneously measure a phase (TOA) and dispersion measure (DM). The code includes a Gaussian-component-based portrait modeling routine. The code uses the python interface to the pulsar data analysis package PSRCHIVE (ascl:1105.014) and also requires the non-linear least-squares minimization package lmfit (ascl:1606.014).

  6. Gravity, Time, and Lagrangians

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2010-01-01

    Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one…

  7. Generalized Canonical Time Warping.

    PubMed

    Zhou, Feng; De la Torre, Fernando

    2016-02-01

    Temporal alignment of human motion has been of recent interest due to its applications in animation, tele-rehabilitation and activity recognition. This paper presents generalized canonical time warping (GCTW), an extension of dynamic time warping (DTW) and canonical correlation analysis (CCA) for temporally aligning multi-modal sequences from multiple subjects performing similar activities. GCTW extends previous work on DTW and CCA in several ways: (1) it combines CCA with DTW to align multi-modal data (e.g., video and motion capture data); (2) it extends DTW by using a linear combination of monotonic functions to represent the warping path, providing a more flexible temporal warp. Unlike exact DTW, which has quadratic complexity, we propose a linear time algorithm to minimize GCTW. (3) GCTW allows simultaneous alignment of multiple sequences. Experimental results on aligning multi-modal data, facial expressions, motion capture data and video illustrate the benefits of GCTW. The code is available at http://humansensing.cs.cmu.edu/ctw. PMID:26761734

  8. Time perception and age.

    PubMed

    Ferreira, Vanessa Fernanda Moreira; Paiva, Gabriel Pina; Prando, Natália; Graça, Carla Renata; Kouyoumdjian, João Aris

    2016-04-01

    Our internal clock system is predominantly dopaminergic, but memory is predominantly cholinergic. Here, we examined the common sensibility encapsulated in the statement: "time goes faster as we get older". Objective To measure a 2 min time interval, counted mentally in subjects of different age groups. Method 233 healthy subjects (129 women) were divided into three age groups: G1, 15-29 years; G2, 30-49 years; and G3, 50-89 years. Subjects were asked to close their eyes and mentally count the passing of 120 s. Results The elapsed times were: G1, mean = 114.9 ± 35 s; G2, mean = 96.0 ± 34.3 s; G3, mean = 86.6 ± 34.9 s. The ANOVA-Bonferroni multiple comparison test showed that G3 and G1 results were significantly different (P < 0.001). Conclusion Mental calculations of 120 s were shortened by an average of 24.6% (28.3 s) in individuals over age 50 years compared to individuals under age 30 years. PMID:27097002

  9. Time Reversal Violation

    SciTech Connect

    Quinn, H; /SLAC

    2009-01-27

    This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focused on the latter, namely the violation of T-reversal invariance in particle physics theories. In sum tests of microscopic T-invariance, or observations of its violation, are limited by the fact that, while we can measure many processes, only in very few cases can we construct a matched pair of process and inverse process and observe it with sufficient sensitivity to make a test. In both the cases discussed here we can achieve an observable T violation making use of flavor tagging, and in the second case also using the quantum properties of an antisymmetric coherent state of two B mesons to construct a CP-tag. Both these tagging properties depend only on very general properties of the flavor and/or CP quantum numbers and so provide model independent tests for T-invariance violations. The microscopic laws of physics are very close to T-symmetric. There are small effects that give CP- and T-violating processes in three-generation-probing weak decays. Where a T-violating observable can be constructed we see the relationships between T-violation and CP-violation expected in a CPT conserving theory. These microscopic effects are unrelated to the 'arrow of time' that is defined by increasing entropy, or in the time direction defined by the expansion of our Universe.

  10. Time, music, and reverie.

    PubMed

    Lombardi, Riccardo

    2008-12-01

    Time is an important source of containment vis-à-vis the pressure of affects and the nondimensional immensity of mental space experienced by difficult patients. A more articulated spatiotemporal integration can be facilitated by the analyst's musical "reverie" during intense emotional exchanges in analytic sessions. This reverie can be visual, olfactory, kinaesthetic, etc., no less than auditory or musical. Music is indeed connected with both the concrete world of bodily sensations and the symbolic expressions of culture, and may be an important transitional phenomenon in analytic communication on both unconscious and conscious levels. Two clinical cases are presented in which the patient's awareness of the passage of time, associated with the analyst's internal musical experiences, made it possible in one case to reduce intense panic attacks and, in the other, to overcome the patient's rigid obsessive defenses, giving him access to fluid and unforeseen emotions. In these two instances of working through, the perception of time helped establish confidence in the creative contribution of the "unheard melodies" (Keats) of affects to the functioning of thought. PMID:19037120

  11. Real-Time PCR

    NASA Astrophysics Data System (ADS)

    Evrard, A.; Boulle, N.; Lutfalla, G. S.

    Over the past few years there has been a considerable development of DNA amplification by polymerase chain reaction (PCR), and real-time PCR has now superseded conventional PCR techniques in many areas, e.g., the quantification of nucleic acids and genotyping. This new approach is based on the detection and quantification of a fluorescent signal proportional to the amount of amplicons generated by PCR. Real-time detection is achieved by coupling a thermocycler with a fluorimeter. This chapter discusses the general principles of quantitative real-time PCR, the different steps involved in implementing the technique, and some examples of applications in medicine. The polymerase chain reaction (PCR) provides a way of obtaining a large number of copies of a double-stranded DNA fragment of known sequence. This DNA amplification technique, developed in 1985 by K. Mullis (Cetus Corporation), saw a spectacular development over the space of a few years, revolutionising the methods used up to then in molecular biology. Indeed, PCR has many applications, such as the detection of small amounts of DNA, cloning, and quantitative analysis (assaying), each of which will be discussed further below.

  12. Commission 31: Time

    NASA Astrophysics Data System (ADS)

    Matsakis, Demetrios; Defraigne, Pascale; Hosokawa, M.; Leschiutta, S.; Petit, G.; Zhai, Z.-C.

    2007-03-01

    The most intensely discussed and controversial issue in time keeping has been the proposal before the International Telecommunications Union (ITU) to redefine Coordinated Universal Time (UTC) so as to replace leap seconds by leap hours. Should this proposal be adopted, the practice of inserting leap seconds would cease after a specific date. Should the Earth's rotation continue to de-accelerate at its historical rate, the next discontinuity in UTC would be an hour inserted several centuries from now. Advocates of this proposal cite the need to synchronize satellite and other systems, such as GPS, Galileo, and GLONASS, which did not exist and were not envisioned when the current system was adopted. They note that leap second insertions can be and have been incorrectly implemented or accounted for. Such errors have to date had localized impact, but they could cause serious mishaps involving loss of life. For example, some GPS receivers have been known to fail simply because there was no leap second after a long enough interval, other GPS receivers failed because the leap second information was broadcast more than three months in advance, and some commercial software used for internet time-transfer Network Time Protocol (NTP) could either discard all data received after a leap second or interpret it as a frequency change. The ambiguity associated with the extra second could also disrupt financial accounting and certain forms of encryption. Those opposed to the proposal question the need for a change, and also point out the costs of adjusting to the proposed change and its inconvenience to amateur astronomers and others who rely upon astronomical calculations published in advance. Reports have been circulated that the cost of checking and correcting software to accommodate the new definition of UTC would be many millions of dollars for some systems. In October 2005 American Astronomical Society asked the ITU for a year's time to study the issue. This commission has

  13. A Matter of Time

    NASA Technical Reports Server (NTRS)

    2006-01-01

    16 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the south polar residual cap where the effects of sublimation are apparent. Over extended periods of time, sublimation 'eats' away at the smoother appearing material (largely composed of frozen carbon dioxide), darkening the scarps and creating the irregularly shaped depressions that are present throughout much of the scene.

    Location near: 87.1oS, 69.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  14. Telescope Time Allocation Tool

    NASA Astrophysics Data System (ADS)

    Alves, J.

    2005-03-01

    TaToo is ESO's new Time Allocation Tool. This software scheduler is a combination of a user-friendly graphical user interface and an intelligent constraint-programming engine fine-tuned to ESO's scheduling problem. TaToo is able to produce a high quality and reliable schedule taking into consideration all constraints of the recommended programs for all telescopes in about 15 minutes. This performance allows schedulers at ESO-VISAS to simulate and evaluate different scenarios, optimize the scheduling of engineering activities at the observatories, and in the end construct the most science efficient schedule possible.

  15. Space-time programming.

    PubMed

    Beal, Jacob; Viroli, Mirko

    2015-07-28

    Computation increasingly takes place not on an individual device, but distributed throughout a material or environment, whether it be a silicon surface, a network of wireless devices, a collection of biological cells or a programmable material. Emerging programming models embrace this reality and provide abstractions inspired by physics, such as computational fields, that allow such systems to be programmed holistically, rather than in terms of individual devices. This paper aims to provide a unified approach for the investigation and engineering of computations programmed with the aid of space-time abstractions, by bringing together a number of recent results, as well as to identify critical open problems. PMID:26078346

  16. Genetic Time Travel.

    PubMed

    Krause, Johannes; Pääbo, Svante

    2016-05-01

    At its core, genetics is a historical discipline. Mutations are passed on from generation to generation and accumulate as a result of chance as well as of selection within and between populations and species. However, until recently, geneticists were confined to the study of present-day genetic variation and could only indirectly make inferences about the historical processes that resulted in the variation in present-day gene pools. This "time trap" has now been overcome thanks to the ability to analyze DNA extracted from ancient remains, and this is about to revolutionize several aspects of genetics. PMID:27183562

  17. Space Time Foam

    NASA Astrophysics Data System (ADS)

    Garattini, Remo

    In the context of a model of space-time foam, made by N wormholes we discuss the possibility of having a foam formed by different configurations. An equivalence between Schwarzschild and Schwarzschild-Anti-de Sitter wormholes in terms of Casimir energy is shown. An argument to discriminate which configuration could represent a foamy vacuum coming from Schwarzschild black hole transition frequencies is used. The case of a positive cosmological constant is also discussed. Finally, a discussion involving charged wormholes leads to the conclusion that they cannot be used to represent a ground state of the foamy type.

  18. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  19. Adult mice transplanted with embryonic retinal progenitor cells: New approach for repairing damaged optic nerves

    PubMed Central

    Cho, Jang-Hyeon; Mao, Chai-An

    2012-01-01

    Purpose Retinal ganglion cell (RGC) death and optic nerve degeneration are complex processes whose underlying molecular mechanisms are only vaguely understood. Treatments commonly used for optic nerve degeneration have little long-term value and only prolong degeneration. Recent advances in stem cell replacement therapy offer new ways to overcome RGC loss by transferring healthy cells into eyes of afflicted individuals. However, studies on stem cell replacement for optic nerve degeneration are hampered by limitations of the available animal models, especially genetic models. We have developed a mouse model in which RGCs are genetically ablated in adult mice with subsequent degeneration of the optic nerve. In the study reported here, we used this model to determine whether embryonic retinal progenitor cells (RPCs) removed from donor retinas when RPCs are committing to an RGC fate could restore lost RGCs. Methods We used the RGC-depleted model as a host for transplanting donor green fluorescent protein (GFP)–labeled RPCs from embryonic retinas that are maximally expressing Atoh7, a basic helix–loop–helix gene essential for RGC specification. Dissociated GFP-labeled RPCs were characterized in situ by immunolabeling with antibodies against proteins known to be expressed in RPCs at embryonic day (E)14.5. Dissociated retinal cells were injected into the vitreous of one eye of RGC-depleted mice at two to six months of age. The injected and non-injected retinas were analyzed for gene expression using immunolabeling, and the morphology of optic nerves was assessed visually and with histological staining at different times up to four months after injection. Results We demonstrate the successful transfer of embryonic GFP-labeled RPCs into the eyes of RGC-depleted mice. Many transplanted RPCs invaded the ganglion cell layer, but the efficiency of the invasion was low. GFP-labeled cells within the ganglion cell layer expressed genes associated with early and late stages

  20. Timing of cyber conflict

    PubMed Central

    Axelrod, Robert; Iliev, Rumen

    2014-01-01

    Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran’s nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide. PMID:24474752

  1. Prime time sexual harrassment.

    PubMed

    Grauerholz, E; King, A

    1997-04-01

    This study explores the explicit and implicit messages of sexual harassment that viewers receive when viewing prime-time television in the US. A content analysis of 48 hours of prime-time television reveals that sexual harassment on television is both highly visible and invisible. Sexual harassment is rendered visible simply by its prominence in these programs. Incidents involving quid-pro-quo harassment and environmental harassment occur with regularity on television. Furthermore, about 84% of the shows studied contained at least one incident of sexual harassment; yet these acts of sexual harassment remained largely invisible because none of the behaviors were labeled as sexual harassment. These incidents are presented in humorous ways, and victims are generally unharmed and very effective at ending the harassment. Although such programs may actually reflect the reality of many women's lives in terms of prevalence of sexual harassment, they perpetuate several myths about sexual harassment, such as that sexual harassment is not serious and that victims should be able to handle the situations themselves. PMID:12294811

  2. Timing of cyber conflict.

    PubMed

    Axelrod, Robert; Iliev, Rumen

    2014-01-28

    Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran's nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide. PMID:24474752

  3. Physics Back in TIME

    NASA Astrophysics Data System (ADS)

    Korsunsky, Boris

    2014-03-01

    Recently, I came into possession of an unusual item: a collection of 1928 TIME magazines. I began flipping through the pages out of sheer curiosity—and was soon astonished by the scale and the depth of their physics coverage. Back then, TIME had a special "Science" section in almost every issue and devoted quite a bit of space to the events that would hardly be mentioned in any popular magazine these days. Some of them were fleeting and merely curious, some truly timeless. Many of the articles and notes were devoted to physics: the people, the discoveries, the inventions, the conventions. I found the reading both entertaining and enlightening and would like to offer a sampler here. I hope that these little tidbits of history will lighten up the classroom discussions and help inspire your students by reminding them that physics is a dynamic, ever-changing field to which they may well contribute one day. I have found that my own students love it when a little bit of history is brought up; it always generates interesting questions and seems to spark the students' interest in the topic.

  4. Timing of intraventricular haemorrhage.

    PubMed Central

    Emerson, P; Fujimura, M; Howat, P; Howes, D; Keeling, J; Robinson, R O; Salisbury, D; Tizard, J P

    1977-01-01

    The detection of the onset of intraventricular haemorrhage (IVH) during life is a necessary preliminary to understanding the cause of this condition. In 10 infants of very low birthweight treated with serial transfusions of adult blood the proportions of transfused cells circulating after each transfusion were compared with the proportion of transfused cells found in the intraventricular clot at necropsy. This allowed the timing of IVH to be restricted retrospectively to the period between consecutive blood transfusions. In addition, the proportional changes of transfused cells produced by infusion of a known red cell mass allow changes in the babies' original red cell mass to be followed during life. A fall in this value occurred in 8 infants dying with IVH and was taken to indicate haemorrhage. Comparison of the two methods in 9 infants suggested that, while in some cases intraventricular bleeding occurs rapidly, in others it takes place over a period of time. The interval between birth and the onset of haemorrhage was directly proportional to the gestational age of the infant. PMID:848996

  5. The Earth Through Time

    NASA Astrophysics Data System (ADS)

    Mertzman, Stanley A.

    The Earth Through Time successfully fills a gap in the world of introductory level geology textbooks, a gulf created by the nature of typical undergraduate students. The introductory course taught at many institutions is physical geology wherein potential geology majors and students who simply want to fulfill part of a natural science requirement form a cosmopolitan class. Students who are convinced that geology is the major for them go on to historical geology in the second semester often using the Dott and Batten text, Evolution of the Earth, a text that is rigorous and designed strictly with the geology major in mind. Based on my experience, however, a sizable number of students who have no intention of majoring in geology desire to take a second course in the field out of pure interest and as a means of satisfying the second part of a typical 2-semester science requirement. The Earth Through Time provides a viable alternative to Dott and Batten's book, one certainly as broad in its overall coverage but with discrete topics—such as local stratigraphic nomenclature and detailed discussions of geology outside of North America—being de-emphasized.

  6. Emergent Space-Time

    NASA Astrophysics Data System (ADS)

    Chapline, George

    It has been shown that a nonlinear Schrödinger equation in 2+1 dimensions equipped with an SU(N) Chern-Simons gauge field can provide an exact description of certain self-dual Einstein spaces in the limit N-=∞. Ricci flat Einstein spaces can then be viewed as arising from a quantum pairing of the classical self-dual and anti-self-dual solutions. In this chapter, we will outline how this theory of empty space-time might be generalized to include matter and vacuum energy by transplanting the nonlinear Schrödinger equation used to construct Einstein spaces to the 25+1-dimensional Lorentzian Leech lattice. If the distinguished 2 spatial dimensions underlying the construction of Einstein spaces are identified with a hexagonal lattice section of the Leech lattice, the wave-function becomes an 11 × 11 matrix that can represent fermion and boson degrees of freedom (DOF) associated with 2-form and Yang-Mills gauge symmetries. The resulting theory of gravity and matter in 3+1 dimensions is not supersymmetric, which provides an entry for a vacuum energy. Indeed, in the case of a Lemaitre cosmological model, the emergent space-time will naturally have a vacuum energy on the order of the observed cosmological constant.

  7. Time-Delay Interferometry

    NASA Astrophysics Data System (ADS)

    Dhurandhar, Sanjeev V.; Tinto, Massimo

    2005-07-01

    Equal-arm interferometric detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called Time-Delay Interferometry (TDI). This article provides an overview of the theory and mathematical foundations of TDI as it will be implemented by the forthcoming space-based interferometers such as the Laser Interferometer Space Antenna (LISA) mission. We have purposely left out from this first version of our "Living Review" article on TDI all the results of more practical and experimental nature, as well as all the aspects of TDI that the data analysts will need to account for when analyzing the LISA TDI data combinations. Our forthcoming "second edition" of this review paper will include these topics.

  8. The Sun in Time

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Bero, Elizabeth; Sever, Thomas L.

    1999-01-01

    Leveraging funds from NASA's Initiative to Develop Education through Astronomy and Space Science (IDEAS) program, we combined the expertise of an archaeoastronomer, a solar scientist, and a teacher to trace humankind's view of the Sun and how that has changed, from the time of Stonehenge in about 1800 B.C.E., to the time of the Maya in 700 C.E., up to the modem era. Our program was aimed at middle-school students in an attempt to explain not only how science is done today, but how science has evolved from the observations of ancient societies. From these varied cultures, we touched on methods of observing the Sun, ideas of the composition of the Sun, and the relationship of the Sun to everyday life. Further, using the von Braun Astronomical Society's Planetarium in Huntsville, Alabama as a test-bed for the program, we illustrated concepts such as solstices, equinoxes, and local noon with approximately 800 eighth grade students from the local area. Our presentation to SEPA will include a description of NASA's IDEAS program and how to go about partnering with a NASA astronomer, some slides from our planetarium program and web-site, and some hands-on activities.

  9. Group Time. Marking Time at Group Time! Add Some Creativity to Charting Dates, Weather, and Time at Group Time!

    ERIC Educational Resources Information Center

    Church, Ellen Booth

    2005-01-01

    Young children are just beginning to develop an understanding of time. In the preschool and kindergarten years children often have difficulty understanding the difference between yesterday, today and tomorrow, much less Monday, Tuesday and Wednesday. This article offers tips that teachers may use to make these abstract concepts less confusing: (1)…

  10. Principles of Discrete Time Mechanics

    NASA Astrophysics Data System (ADS)

    Jaroszkiewicz, George

    2014-04-01

    1. Introduction; 2. The physics of discreteness; 3. The road to calculus; 4. Temporal discretization; 5. Discrete time dynamics architecture; 6. Some models; 7. Classical cellular automata; 8. The action sum; 9. Worked examples; 10. Lee's approach to discrete time mechanics; 11. Elliptic billiards; 12. The construction of system functions; 13. The classical discrete time oscillator; 14. Type 2 temporal discretization; 15. Intermission; 16. Discrete time quantum mechanics; 17. The quantized discrete time oscillator; 18. Path integrals; 19. Quantum encoding; 20. Discrete time classical field equations; 21. The discrete time Schrodinger equation; 22. The discrete time Klein-Gordon equation; 23. The discrete time Dirac equation; 24. Discrete time Maxwell's equations; 25. The discrete time Skyrme model; 26. Discrete time quantum field theory; 27. Interacting discrete time scalar fields; 28. Space, time and gravitation; 29. Causality and observation; 30. Concluding remarks; Appendix A. Coherent states; Appendix B. The time-dependent oscillator; Appendix C. Quaternions; Appendix D. Quantum registers; References; Index.

  11. Multichannel time-slot permuters

    NASA Astrophysics Data System (ADS)

    Jordan, Harry F.; Lee, Kyungsook Y.; Lee, Daeshik

    1993-02-01

    We consider the general switching problem known as time-space-time domain permutations in telecommunications. We present a new set of multichannel time slot permuters for L parallel frames of M time slots (L equals 2l, M equals 2m). The multichannel time slot permuters are obtained by combining L X L spatial networks and time slot permuters for a frame of M time slots. In this paper, the Benes network, the Batcher sorter and the Lambda network for spatial networks, and their counterparts, the RJS time slot permuter, the S time slot sorter, and the Lambda time slot permuter are considered.

  12. Memory on time

    PubMed Central

    Eichenbaum, Howard

    2013-01-01

    Considerable recent work has shown that the hippocampus is critical for remembering the order of events in distinct experiences, a defining feature of episodic memory. Correspondingly, hippocampal neuronal activity can ‘replay’ sequential events in memories and hippocampal neuronal ensembles represent a gradually changing temporal context signal. Most strikingly, single hippocampal neurons – called time cells – encode moments in temporally structured experiences much as the well-known place cells encode locations in spatially structured experiences. These observations bridge largely disconnected literatures on the role of the hippocampus in episodic memory and spatial mapping, and suggest that the fundamental function of the hippocampus is to establish spatio-temporal frameworks for organizing memories. PMID:23318095

  13. Time encoded radiation imaging

    DOEpatents

    Marleau, Peter; Brubaker, Erik; Kiff, Scott

    2014-10-21

    The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

  14. Real time automated inspection

    DOEpatents

    Fant, Karl M.; Fundakowski, Richard A.; Levitt, Tod S.; Overland, John E.; Suresh, Bindinganavle R.; Ulrich, Franz W.

    1985-01-01

    A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

  15. Real time automated inspection

    DOEpatents

    Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

    1985-05-21

    A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

  16. ETC: Exposure Time Calculator

    NASA Astrophysics Data System (ADS)

    Hirata, Christopher M.; Gehrels, Neil; Kneib, Jean-Paul; Kruk, Jeffrey; Rhodes, Jason; Wang, Yun; Zoubian, Julien

    2013-11-01

    Written for the Wide-Field Infrared Survey Telescope (WFIRST) high-latitude survey, the exposure time calculator (ETC) works in both imaging and spectroscopic modes. In addition to the standard ETC functions (e.g. background and S/N determination), the calculator integrates over the galaxy population and forecasts the density and redshift distribution of galaxy shapes usable for weak lensing (in imaging mode) and the detected emission lines (in spectroscopic mode). The program may be useful outside of WFIRST but no warranties are made regarding its suitability for general purposes. The software is available for download; IPAC maintains a web interface for those who wish to run a small number of cases without having to download the package.

  17. Solar wind travel time

    NASA Astrophysics Data System (ADS)

    Russell, C. T.

    A useful rule of thumb in solar terrestrial studies is that the solar wind travels 4 Earth radii (RE) per minute. Long-term studies of solar wind velocity [e.g., Luhmann et al., 1993; 1994] show that the median velocity is about 420 km/s, corresponding to 3.96 RE min-1. The quartiles are about 370 km/s and 495 km/s, corresponding to 3.48 Re min-1 and 4.66 Re min-1 respectively. This number helps estimate the delays expected when observing a discontinuity at a solar wind monitor; one example is ISEE-3 when it was at the forward libration point (about 60 min). It is also helpful for estimating how much time passes before the dayside magnetosphere is compressed as denser solar wind flows by (about 2.5 min).

  18. Laser Frequency and Time

    NASA Astrophysics Data System (ADS)

    Hänsch, Theodor W.

    2003-04-01

    The following two contributions in this volume are highlighting some remarkable recent developments at the interface between precision laser spectroscopy and ultrafast laser physics. After decades of struggle, we have finally found a practical method for measuring the frequency of light with extreme precision [1]. Femtosecond laser optical frequency comb synthesizers are opening exciting new perspectives for atomic spectroscopy and they can provide the clockwork for optical atomic clocks that will eventually far surpass the accuracy of the best microwave cesium clocks. J. C. Bergquist et al. [2] are reporting on a first optical atomic clock at NIST based on a single trapped Hg+ ion. The contribution by Jun Ye et al. [3] is illustrating the wealth of new opportunities for femtosecond laser frequency combs in the frequency and time domain.

  19. Cell complexes through time

    NASA Astrophysics Data System (ADS)

    Klette, Reinhard

    2000-10-01

    The history of cell complexes is closely related to the birth and development of topology in general. Johann Benedict Listing (1802 - 1882) introduced the term 'topology' into mathematics in a paper published in 1847, and he also defined cell complexes for the first time in a paper published in 1862. Carl Friedrich Gauss (1777 - 1855) is often cited as the one who initiated these ideas, but he did not publish either on topology or on cell complexes. The pioneering work of Leonhard Euler (1707 - 1783) on graphs is also often cited as the birth of topology, and Euler's work was cited by Listing in 1862 as a stimulus for his research on cell complexes. There are different branches in topology which have little in common: point set topology, algebraic topology, differential topology etc. Confusion may arise if just 'topology' is specified, without clarifying the used concept. Topological subjects in mathematics are often related to continuous models, and therefore quite irrelevant to computer based solutions in image analysis. Compared to this, only a minority of topology publications in mathematics addresses discrete spaces which are appropriate for computer-based image analysis. In these cases, often the notion of a cell complex plays a crucial role. This paper briefly reports on a few of these publications. This paper is not intended to cover the very lively progress in cell complex studies within the context of image analysis during the last two decades. Basically it stops its historic review at the time when this subject in image analysis research gained speed in 1980 - 1990. As a general point of view, the paper indicates that image analysis contributes to a fusion of topological concepts, the geometric and the abstract cell structure approach and point set topology, which may lead towards new problems for the study of topologies defined on geometric or abstract cell complexes.

  20. On time reversal mirrors

    NASA Astrophysics Data System (ADS)

    Fannjiang, Albert C.

    2009-09-01

    The concept of time reversal (TR) of a scalar wave is reexamined from basic principles. Five different time-reversal mirrors (TRMs) are introduced and their relations are analyzed. For the boundary behavior, it is shown that for a paraxial wave only the monopole TR scheme satisfies the exact boundary condition while for the spherical wave only the MD-mode TR scheme satisfies the exact boundary condition. The asymptotic analysis of the near-field focusing property is presented for two dimensions and three dimensions. It is shown that to have a subwavelength focal spot, the TRM should consist of dipole transducers. The transverse resolution of the dipole TRM is linearly proportional to the distance between the point source and the TRM. The mixed mode TRM has the similar (linear) behavior in three dimensions, but in two dimensions the transverse resolution behaves as the square root of the distance between the point source and the TRM. The monopole TRM is ineffective in focusing below the wavelength. Contrary to the matched field processing and the phase processor, both of which resemble TR, TR in a weak- or non-scattering medium is usually biased in the longitudinal direction, especially when TR is carried out on a single plane with a finite aperture. This is true for all five TR schemes. On the other hand, the TR focal spot has been shown repeatedly in the literature, both theoretically and experimentally, to be centered at the source point when the medium is multiple scattering. A reconciliation of the two seemingly conflicting results is found in the random fluctuations in the intensity of the Green function for a multiple scattering medium and the notion of scattering-enlarged effective aperture.

  1. Timing in the Testis.

    PubMed

    Bittman, Eric L

    2016-02-01

    The testis provides not just one but several models of temporal organization. The complexity of its rhythmic function arises in part from its compartmentalization and diversity of cell types: not only does the testis produce gametes, but it also serves as the major source of circulating androgens. Within the seminiferous tubules, the germ cells divide and differentiate while in intimate contact with Sertoli cells. The tubule is highly periodic: a spermatogenic wave travels along its length to determine the timing of the commitment of spermatogonia to differentiate, the phases of meiotic division, and the rate of differentiation of the postmeiotic germ cells. Recent evidence indicates that oscillations of retinoic acid play a major role in determining periodicity of the seminiferous epithelium. In the interstitial space, Leydig cells produce the steroid hormones required both for the completion of spermatogenesis and the development and maintenance of male sexual characteristics throughout the body. This endocrine output also oscillates; although the pulse generator lies outside the gonad, the steroidogenic function of Leydig cells is tuned to a regular episodic input. While the oscillations of the intratubular and interstitial cells have multihour (ultradian) and multiday (infradian) periodicities, respectively, the functions of both compartments also display dramatic seasonal rhythms. Furthermore, circadian rhythms are evident in some of the cell types, although their amplitude and pervasiveness are not as great as in many other tissues of the same organism, and their detection may require methods that recognize the heterogeneity of the testis. This review examines the periodicity of testicular function along multiple time scales. PMID:26656623

  2. Engaged Time in the Classroom

    ERIC Educational Resources Information Center

    Johns E., Beverly H.; Crowley, Paula; Guetzloe, Eleanor

    2008-01-01

    Foremost in an effective curriculum for students with emotional and behavioral disorder (E/BD) is a high level of engaged time--time spent doing meaningful learning activities. Engaged time (time-on-task) is the portion of instructional time that students spend directly involved in learning activities. Walker and Severson (1992) defined the…

  3. Time to redefine Myeloma.

    PubMed

    Pratt, Guy; Bowcock, Stella; Chantry, Andrew; Cook, Gordon; Jackson, Graham; Lai, Maggie; Low, Eric; Mulholland, Nicola; Owen, Roger; Rabin, Neil; Ramasamy, Karthik; Snowden, John A; Streetly, Matthew; Wechalekar, Ashutosh; Yong, Kwee; Bird, Jenny

    2015-10-01

    In November 2014 the International Myeloma Working Group (IMWG) revised the definition of multiple myeloma, such that asymptomatic patients with newly diagnosed multiple myeloma without any of the traditional 'CRAB' (hypercalcaemia, renal impairment, anaemia, bone disease) end organ damage criteria but with one of three new criteria would be recommended to start treatment. Previously, the standard of care for such patients was expectant management. These three new criteria are: greater than 60% clonal plasma cells on bone marrow biopsy, a serum free light chain (sFLC) ratio of >100 (the involved sFLC must be >100 mg/l) and greater than one unequivocal focal lesion on advanced imaging (low dose whole body computerized tomography, magnetic resonance imaging, (18) F fluorodeoxyglucose positron emission tomography). Although this would appear to affect a small number of patients, the impact of these changes are broad, leading to an increased use of advanced imaging, a debate around the management of patients previously diagnosed with smouldering myeloma, changed terminology and clinical trial design and an extension of the use of biomarkers. For the first time the philosophy of treatment in myeloma will change from treatment initiation only being triggered by overt end organ damage to an era where sub clinical risk factors will also be taken into account. PMID:26221971

  4. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

  5. Variable camshaft timing system

    SciTech Connect

    Sapienza, S.J.

    1988-05-17

    A variable camshaft timing system in combination with an internal combustion engine having at least one cylinder, a rotatable member such as a crankshaft, and an intake and exhaust valve coupled to an intake camshaft and an exhaust camshaft respectively, the system is described comprising: a pulley wheel fixedly attached at one end of each of the intake and exhaust camshafts and the crankshaft; belt means interconnecting each of the pulley wheels for transferring rotational motion from the crankshaft to the intake and exhaust camshafts; first and second idler arm means pivotally attached to the engine, each of the idler arm means having a pivoting arm, a cam follower arm and an idler wheel in operative contact with the belt means; positioning cam means operatively coupled to each of the cam follower arms of the idler arm means; a control means responsive to various engine operating parameters for generating motor control signals; and electric motor means responsive to the motor control signals and operatively coupled to rotate the positioning cams means for positioning each of the idler arm means for changing the relative rotational position between the input camshaft and the exhaust camshaft.

  6. Conformal gravity and time

    NASA Astrophysics Data System (ADS)

    Hazboun, Jeffrey Shafiq

    2014-10-01

    Cartan geometry provides a rich formalism from which to look at various geometrically motivated extensions to general relativity. In this manuscript, we start by motivating reasons to extend the theory of general relativity. We then introduce the reader to our technique, called the quotient manifold method, for extending the geometry of spacetime. We will specifically look at the class of theories formed from the various quotients of the conformal group. Starting with the conformal symmetries of Euclidean space, we construct a manifold where time manifests as a part of the geometry. Though there is no matter present in the geome- try studied here, geometric terms analogous to dark energy and dark matter appear when we write down the Einstein tensor. Specifically, the quotient of the conformal group of Euclidean four-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and nondegenerate Killing metric. We show the general solution possesses orthogonal Lagrangian submanifolds, with the induced metric and the spin connection on the submanifolds necessarily Lorentzian, despite the Euclidean starting point. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find two new tensor fields exist in this geometry, not present in Riemannian geometry. The first is a combination of the Weyl vector with the scale factor on the metric, and determines the time-like directions on the submanifolds. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection, it transforms ho- mogeneously. Finally, we show in the absence of Cartan curvature or sources, the configuration space has geometric terms equivalent to a perfect fluid and a cosmological constant. We complete the analysis of this homogeneous space by

  7. SLH Timing Belt Powertrain

    SciTech Connect

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  8. Time to talk condoms.

    PubMed

    Piotrow, P T; Rinehart, W

    1991-09-01

    A great deal of avoided if political and religious leaders, educators, health care providers and the mass media would band together in an effort to promote condom use. Condoms use protects against unwanted pregnancies, STDs and AIDS. Yet, public discussions on condom use are rate. In the US, political leaders avoid mentioning the topic, and television networks severely restrict the airing of public service announcements for condoms. Worldwide, an estimated 100 billion acts of sexual intercourse take place every year. A recent report indicates that it would take a modest 13 billion condoms a year to protect everyone who is at risk of contracting AIDS and other STDs, and risk of having an unwanted pregnancy. Currently, worldwide production of condoms stands at about 6 billion a year. Furthermore, condom makers have the capacity to increase production by some 2 billion, and could add new capacity in about 2 years. Many believe that marketing condoms is a difficult enterprise, since men often report that condoms reduce pleasure, cause embarrassment, or are not available when needed. The challenge for markets, then, is to create demand. This is especially true in the US, where prime-time advertising and the use of popular entertainment, such as soap operas, could promote condoms as both safe and satisfying. In the developing world, the challenge is to make condoms widely available and affordable. Some changes have taken place since 1981, when AIDS first came into the spotlight. In the US, people now discuss the topic of STDs more openly. But an all-out effort to promote condom use has not yet begun. PMID:12284290

  9. TIMED Imaging Photometer Experiment (TIPE)

    NASA Technical Reports Server (NTRS)

    Mende, Stephen B.; Fritts, D. C.; Hecht, James H.; Killeen, T. L.; Llewellyn, Edward J.; Lowe, Robert P.; Mcdade, Ian C.; Ross, Martin N.; Swenson, Gary R.; Turnbull, David N.

    1994-01-01

    This document contains a summary of the TIMED Imaging Photometer Experiment (TIPE) instrument study at the time of the termination of project due to TIPE being de-selected from the Thermosphere, Ionosphere and Mesosphere Energetics and Dynamics (TIMED) mission.

  10. Management Styles and Techniques: Time.

    ERIC Educational Resources Information Center

    Matthews, Priscilla J.

    1987-01-01

    Discusses strategies to improve individuals' use of time and personal satisfaction through time management. The 126-item bibliography includes citations for time management in general and special sections for career development, family and parenting, women, and home management. (CLB)

  11. Fourteen Times the Earth

    NASA Astrophysics Data System (ADS)

    2004-08-01

    ESO HARPS Instrument Discovers Smallest Ever Extra-Solar Planet Summary A European team of astronomers [1] has discovered the lightest known planet orbiting a star other than the sun (an "exoplanet"). The new exoplanet orbits the bright star mu Arae located in the southern constellation of the Altar. It is the second planet discovered around this star and completes a full revolution in 9.5 days. With a mass of only 14 times the mass of the Earth, the new planet lies at the threshold of the largest possible rocky planets, making it a possible super Earth-like object. Uranus, the smallest of the giant planets of the Solar System has a similar mass. However Uranus and the new exoplanet differ so much by their distance from the host star that their formation and structure are likely to be very different. This discovery was made possible by the unprecedented accuracy of the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, which allows radial velocities to be measured with a precision better than 1 m/s. It is another clear demonstration of the European leadership in the field of exoplanet research. PR Photo 25a/04: The HARPS Spectrograph and the 3.6m Telescope PR Photo 25b/04: Observed Velocity Variation of mu Arae (3.6m/HARPS, 1.2m Swiss/CORALIE, AAT/UCLES) PR Photo 25c/04: Velocity Variation of mu Arae Observed by HARPS (3.6m/HARPS) PR Photo 25d/04: "Velocity Curve" of mu Arae A unique planet hunting machine ESO PR Photo 25a/04 ESO PR Photo 25a/04 The HARPS Spectrograph and the 3.6m Telescope [Preview - JPEG: 602 x 400 pix - 211k] [Normal - JPEG: 1202 x 800 pix - 645k] Caption: ESO PR Photo 25a/04 represents a montage of the HARPS spectrograph and the 3.6m telescope at La Silla. The upper left shows the dome of the telescope, while the upper right illustrates the telescope itself. The HARPS spectrograph is shown in the lower image during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen. Since the first

  12. Physical Time and Thermal Clocks

    NASA Astrophysics Data System (ADS)

    Borghi, Claudio

    2016-07-01

    In this paper I discuss the concept of time in physics. I consider the thermal time hypothesis and I claim that thermal clocks and atomic clocks measure different physical times, whereby thermal time and relativistic time are not compatible with each other. This hypothesis opens the possibility of a new foundation of the theory of physical time, and new perspectives in theoretical and philosophical researches.

  13. 16 CFR 1101.22 - Timing: request for time extensions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Information Officer may provide a different amount of time for comment, particularly for firms that receive... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Timing: request for time extensions. 1101.22... Providing Notice and Opportunity To Comment Under Section 6(b)(1) § 1101.22 Timing: request for...

  14. 16 CFR 1101.22 - Timing: request for time extensions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Information Officer may provide a different amount of time for comment, particularly for firms that receive... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Timing: request for time extensions. 1101.22... Providing Notice and Opportunity To Comment Under Section 6(b)(1) § 1101.22 Timing: request for...

  15. Group Time: Taking a "Humor Break" at Group Time

    ERIC Educational Resources Information Center

    Church, Ellen Booth

    2005-01-01

    January is a perfect time to insert a strong dose of humor into group time gatherings. Oftentimes, children have tired of the predictable pattern of group meetings and need some change. Humor-filled group time activities can be the best secret remedy. Not only will children become more interested in the group time meetings (and therefore listen…

  16. GALAXIES: SNAPSHOTS IN TIME

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This sequence of NASA Hubble Space Telescope (HST) images of remote galaxies offers tantalizing initial clues to the evolution of galaxies in the universe. [far left column] These are traditional spiral and elliptical-shaped galaxies that make up the two basic classes of island star cities that inhabit the universe we see in our current epoch (14 billion years after the birth of the universe in the Big Bang). Elliptical galaxies contain older stars, while spirals have vigorous ongoing star formation in their dusty, pancake-shaped disks. Our Milky Way galaxy is a typical spiral, or disk-shaped galaxy, on the periphery of the great Virgo cluster. Both galaxies in this column are a few tens of millions of light-years away, and therefore represent our current stage of the universe s evolution. [center left column] These galaxies existed in a rich cluster when the universe was approximately two-thirds its present age. Elliptical galaxies (top) appear fully evolved because they resemble today's descendants. By contrast, some spirals have a frothier appearance, with loosely shaped arms of young star formation. The spiral population appears more disrupted due to a variety of possible dynamical effects that result from dwelling in a dense cluster. [center right column] Distinctive spiral structure appears more vague and disrupted in galaxies that existed when the universe was nearly one-third its present age. These objects do not have the symmetry of current day spirals and contain irregular lumps of starburst activity. However, even this far back toward the beginning of time, the elliptical galaxy (top) is still clearly recognizable. However, the distinction between ellipticals and spirals grows less certain with increasing distance. [far right column] These extremely remote, primeval objects existed with the universe was nearly one-tenth its current age. The distinction between spiral and elliptical galaxies may well disappear at this early epoch. However, the object in

  17. Fourteen Times the Earth

    NASA Astrophysics Data System (ADS)

    2004-08-01

    ESO HARPS Instrument Discovers Smallest Ever Extra-Solar Planet Summary A European team of astronomers [1] has discovered the lightest known planet orbiting a star other than the sun (an "exoplanet"). The new exoplanet orbits the bright star mu Arae located in the southern constellation of the Altar. It is the second planet discovered around this star and completes a full revolution in 9.5 days. With a mass of only 14 times the mass of the Earth, the new planet lies at the threshold of the largest possible rocky planets, making it a possible super Earth-like object. Uranus, the smallest of the giant planets of the Solar System has a similar mass. However Uranus and the new exoplanet differ so much by their distance from the host star that their formation and structure are likely to be very different. This discovery was made possible by the unprecedented accuracy of the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, which allows radial velocities to be measured with a precision better than 1 m/s. It is another clear demonstration of the European leadership in the field of exoplanet research. PR Photo 25a/04: The HARPS Spectrograph and the 3.6m Telescope PR Photo 25b/04: Observed Velocity Variation of mu Arae (3.6m/HARPS, 1.2m Swiss/CORALIE, AAT/UCLES) PR Photo 25c/04: Velocity Variation of mu Arae Observed by HARPS (3.6m/HARPS) PR Photo 25d/04: "Velocity Curve" of mu Arae A unique planet hunting machine ESO PR Photo 25a/04 ESO PR Photo 25a/04 The HARPS Spectrograph and the 3.6m Telescope [Preview - JPEG: 602 x 400 pix - 211k] [Normal - JPEG: 1202 x 800 pix - 645k] Caption: ESO PR Photo 25a/04 represents a montage of the HARPS spectrograph and the 3.6m telescope at La Silla. The upper left shows the dome of the telescope, while the upper right illustrates the telescope itself. The HARPS spectrograph is shown in the lower image during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen. Since the first

  18. Are animals stuck in time?

    PubMed

    Roberts, William A

    2002-05-01

    People can time travel cognitively because they can remember events having occurred at particular times in the past (episodic memory) and because they can anticipate new events occurring at particular times in the future. The ability to assign points in time to events arises from human development of a sense of time and its accompanying time-keeping technology. The hypothesis is advanced that animals are cognitively stuck in time: that is, they have no sense of time and thus have no episodic memory or ability to anticipate long-range future events. Research on animals' abilities to detect time of day, track short time intervals, remember the order of a sequence of events, and anticipate future events are considered, and it is concluded that the stuck-in-time hypothesis is largely supported by the current evidence. PMID:12002698

  19. Simulation of RPC performance for 511 keV photon detection

    NASA Astrophysics Data System (ADS)

    Lippmann, C.; Vincke, H.; Riegler, W.

    2009-05-01

    Measurements of the time resolution of timing Resistive Plate Chambers (RPCs) reveal some differences when comparing the results for 511 keV photons and for particle beams. The subject is of interest, since timing RPCs are currently considered for Positron Emission Tomography (PET), where the sensitivity of the system depends largely on the time resolution of the detector. In this publication we discuss possible explanations, in particular the statistical fluctuations of the deposited charge and the Compton electron flight time distributions. Moreover, we rediscuss the reduction of the Townsend coefficient due to the space charge effect inside the avalanches as a function of the avalanche size. We shall see that the dependence assumed by different analytic models differs significantly from what is predicted by detailed Monte Carlo avalanche simulations.

  20. EDITORIAL: Interesting times

    NASA Astrophysics Data System (ADS)

    Dobson Honorary Editor, Ken

    1996-01-01

    `May you live in interesting times' - old Chinese curse. First, many thanks to John Avison, the retiring Honorary Editor, for his hard work over the last five years, and the steady development in style and content under his stewardship. I can only hope to live up to the standards that he set. The next five years will take us into a new millenium, an event preceded - in England and Wales at least - by a period of stability, reflection and consolidation in education. Or so we are told - but whether such a self-denying ordinance will actually be maintained by the Government both before and after an election in 1997 remains to be seen. Nevertheless, we shall be thankful for any mercies, however small, that permit forward thinking rather than instant response. One of the things that readers of a journal called Physics Education should be thinking about is the continued decline in the numbers of students studying physics post-16. This is not a purely local phenomenon; most European countries are finding a similar decline. There are exceptions, of course: in Scotland numbers studying physics for Highers are increasing. Is such a decline a good thing or a bad thing? Only a minority of post-16 physics students go on to use the bulk of what they have learned in further studies or vocations. Does a knowledge and understanding of physics contribute to the mental well-being and cultural level - let alone material comfort - of any except those who use physics professionally? Is physics defensible as a contribution to the mental armoury of the educated citizen - compared with chemistry, biology - or Latin, say? Or should one rephrase that last question as `Is physics as we teach it today defensible...?' Such questions, and many others no doubt, may well be in the mind of the new Curriculum Officer appointed by the Institute of Physics `to engage in a wide-ranging consultation throughout the entire physics community on the nature and style of post-16 physics programmes, with a

  1. 49 CFR 236.109 - Time releases, timing relays and timing devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES... predetermined time interval, which shall be shown on the plans or marked on the time release, timing relay,...

  2. Setting Time Limits on Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2011-01-01

    It is shown how the time limit on a test can be set to control the probability of a test taker running out of time before completing it. The probability is derived from the item parameters in the lognormal model for response times. Examples of curves representing the probability of running out of time on a test with given parameters as a function…

  3. Real-Time Benchmark Suite

    Energy Science and Technology Software Center (ESTSC)

    1992-01-17

    This software provides a portable benchmark suite for real time kernels. It tests the performance of many of the system calls, as well as the interrupt response time and task response time to interrupts. These numbers provide a baseline for comparing various real-time kernels and hardware platforms.

  4. Flow of Time: Perceiving the passage of time: neural possibilities

    PubMed Central

    Muller, Timothy; Nobre, Anna C

    2014-01-01

    Although the study of time has been central to physics and philosophy for millennia, questions of how time is represented in the brain and how this representation is related to time perception have only recently started to be addressed. Emerging evidence subtly yet profoundly challenges our intuitive notions of time over short scales, offering insight into the nature of the brain's representation of time. Numerous different models, specified at the neural level, of how the brain may keep track of time have been proposed. These models differ in various ways, such as whether time is represented by a centralized or distributed neural system, or whether there are neural systems dedicated to the problem of timing. This paper reviews the insight offered by behavioral experiments and how these experiments refute and guide some of the various models of the brain's representation of time. PMID:25257798

  5. The Length of Time's Arrow

    SciTech Connect

    Feng, Edward H.; Crooks, Gavin E.

    2008-08-21

    An unresolved problem in physics is how the thermodynamic arrow of time arises from an underlying time reversible dynamics. We contribute to this issue by developing a measure of time-symmetry breaking, and by using the work fluctuation relations, we determine the time asymmetry of recent single molecule RNA unfolding experiments. We define time asymmetry as the Jensen-Shannon divergencebetween trajectory probability distributions of an experiment and its time-reversed conjugate. Among other interesting properties, the length of time's arrow bounds the average dissipation and determines the difficulty of accurately estimating free energy differences in nonequilibrium experiments.

  6. Measures of time in astronomy.

    NASA Technical Reports Server (NTRS)

    Mulholland, J. D.

    1972-01-01

    Astronomically-important measures of time are discussed with their definitions, their intended purposes, and areas of viability or obsolescence. Several different kinds of year are defined. Earth rotation time is described in terms of sidereal and solar time and in terms of universal time (UT) for which four different levels are defined corresponding to different approximations of 'uniform' time. The formal definition of ephemeris time, consisting of a defined rate and epoch, is discussed and some unorthodox criticisms are presented. Uses of broadcast time are noted. In the discussion of what measure of time should be used in astronomical applications, it is stated that, at present, all dynamical applications should use a measure of time based on atomic clock time.

  7. Television Programming during "People's Time."

    ERIC Educational Resources Information Center

    Austin, Bruce A.

    A study was initiated to answer questions concerning television programing during "people's time" in a medium-sized market. "People's time" is defined as local prime time from 4:00 p.m. to 8:00 p.m. as contrasted with prime or network time and is considered a time when local broadcasters have an opportunity to serve their audience's…

  8. Time is of the essence.

    PubMed

    Nobre, Anna Christina; O'Reilly, Jill

    2004-09-01

    Timing is essential to human behaviour, but the neural mechanisms underlying time perception are still unclear. New findings from a brain-imaging study by Coull et al. show that activity in a network of motor-related areas varies parametrically with attention to time. Given that a system in which timing is important (but not the primary function) is recruited when temporal judgements are required, we should perhaps reassess the notion of a dedicated timing system in the brain. PMID:15350237

  9. 51. LINES AT TIME OFFICE NO. 13 AT CHECKOUT TIME. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. LINES AT TIME OFFICE NO. 13 AT CHECKOUT TIME. SEAPLANE HANGARS (BLDGS. 1-2) IN BACKGROUND. USN PHOTO, JULY 11, 1941. - Quonset Point Naval Air Station, Roger Williams Way, North Kingstown, Washington County, RI

  10. Time to Learn, Time to Develop? Change Processes in Three Schools with Weak National Time Regulation

    ERIC Educational Resources Information Center

    Nyroos, Mikaela

    2007-01-01

    This article analyses change of time use and time allocation in three schools participating in a Swedish five-year national experiment in which State regulation of teaching time was weakened. Participating schools could freely decide how to use and distribute teaching time. The experiment was launched at a late stage in a 25-year decentralisation…

  11. Time concurrency/phase-time synchronization in digital communications networks

    NASA Technical Reports Server (NTRS)

    Kihara, Masami; Imaoka, Atsushi

    1990-01-01

    Digital communications networks have the intrinsic capability of time synchronization which makes it possible for networks to supply time signals to some applications and services. A practical estimation method for the time concurrency on terrestrial networks is presented. By using this method, time concurrency capability of the Nippon Telegraph and Telephone Corporation (NTT) digital communications network is estimated to be better than 300 ns rms at an advanced level, and 20 ns rms at final level.

  12. Artifacts in digital coincidence timing.

    PubMed

    Moses, W W; Peng, Q

    2014-11-01

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into a time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator.All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e. the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the 'optimal' method. The purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization. PMID:25321885

  13. Artifacts in Digital Coincidence Timing

    PubMed Central

    Moses, W. W.; Peng, Q.

    2014-01-01

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into a time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator. All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e., the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the “optimal” method. The purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization. PMID:25321885

  14. Artifacts in digital coincidence timing

    NASA Astrophysics Data System (ADS)

    Moses, W. W.; Peng, Q.

    2014-11-01

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into a time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator. All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e. the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the ‘optimal’ method. The purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization.

  15. Artifacts in digital coincidence timing

    SciTech Connect

    Moses, W. W.; Peng, Q.

    2014-10-16

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into a time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator.All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e. the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the 'optimal' method. In conclusion, the purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization.

  16. Time for Time on Task and Quality Instruction

    ERIC Educational Resources Information Center

    Masci, Frank

    2008-01-01

    Time on task, with its twin elements of purposeful use of "time" and rededication to ensuring the quality of the "task," presents educators at all levels with the opportunity to effect change through relatively straightforward means. The purpose of this article is to highlight several aspects of using time effectively through a series of…

  17. Time in the Mind: Using Space to Think about Time

    ERIC Educational Resources Information Center

    Casasanto, Daniel; Boroditsky, Lera

    2008-01-01

    How do we construct abstract ideas like justice, mathematics, or time-travel? In this paper we investigate whether mental representations that result from physical experience underlie people's more abstract mental representations, using the domains of space and time as a testbed. People often talk about time using spatial language (e.g., a "long"…

  18. Precise time and time interval data handling and reduction

    NASA Technical Reports Server (NTRS)

    Fisher, L. C.

    1973-01-01

    In the past year, the increase in Precise Time And Time Interval data to be reduced to the U.S. Naval Observatory Master Clock and the requirement for its quick dissemination has necessitated development of more efficient methods of data handling and reduction. An outline of the data involved and of the Time Service computerization of these functions is presented.

  19. Has the Marital Time Cost of Parenting Changed over Time?

    ERIC Educational Resources Information Center

    Dew, Jeffrey

    2009-01-01

    Qualitative and quantitative research has suggested that married couples handle the increasing demands of intensive parenting norms and work expectations by reducing spousal time (e.g., the time that spouses spend alone with each other). Using nationally representative time-diary data, this study examined whether married individuals with children…

  20. The Time Famine: Toward a Sociology of Work Time.

    ERIC Educational Resources Information Center

    Perlow, Leslie A.

    1999-01-01

    A nine-month field study of a software-engineering firm's work practices revealed that the group's collective use of time perpetuated its members'"time famine." A crisis mentality and rewards for individual heroics were responsible. Altering the way engineers used their time at work enhanced their collective productivity. (66 references) (MLH)

  1. Nagios Down-Time scripts

    Energy Science and Technology Software Center (ESTSC)

    2014-11-11

    The Nagios Down-Time scripts are a set of Python scripts that create a commandline interface to Nagios' scheduled down-times. This allows for large-scale management of down-times, beyond what is feasible with the default web interface. Additionally, one of the scripts can be setup to periodically send emails of down-times that are scheduled to end within a specified amount of time after the script has been run; for example, it could run once a day andmore » send an email including down-times ending within the next 24 hours.« less

  2. Response times to conceptual questions

    NASA Astrophysics Data System (ADS)

    Lasry, Nathaniel; Watkins, Jessica; Mazur, Eric; Ibrahim, Ahmed

    2013-09-01

    We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.

  3. Nagios Down-Time scripts

    SciTech Connect

    Buddeberg, Patrick

    2014-11-11

    The Nagios Down-Time scripts are a set of Python scripts that create a commandline interface to Nagios' scheduled down-times. This allows for large-scale management of down-times, beyond what is feasible with the default web interface. Additionally, one of the scripts can be setup to periodically send emails of down-times that are scheduled to end within a specified amount of time after the script has been run; for example, it could run once a day and send an email including down-times ending within the next 24 hours.

  4. Time and timing in the acoustic recognition system of crickets

    PubMed Central

    Hennig, R. Matthias; Heller, Klaus-Gerhard; Clemens, Jan

    2014-01-01

    The songs of many insects exhibit precise timing as the result of repetitive and stereotyped subunits on several time scales. As these signals encode the identity of a species, time and timing are important for the recognition system that analyzes these signals. Crickets are a prominent example as their songs are built from sound pulses that are broadcast in a long trill or as a chirped song. This pattern appears to be analyzed on two timescales, short and long. Recent evidence suggests that song recognition in crickets relies on two computations with respect to time; a short linear-nonlinear (LN) model that operates as a filter for pulse rate and a longer integration time window for monitoring song energy over time. Therefore, there is a twofold role for timing. A filter for pulse rate shows differentiating properties for which the specific timing of excitation and inhibition is important. For an integrator, however, the duration of the time window is more important than the precise timing of events. Here, we first review evidence for the role of LN-models and integration time windows for song recognition in crickets. We then parameterize the filter part by Gabor functions and explore the effects of duration, frequency, phase, and offset as these will correspond to differently timed patterns of excitation and inhibition. These filter properties were compared with known preference functions of crickets and katydids. In a comparative approach, the power for song discrimination by LN-models was tested with the songs of over 100 cricket species. It is demonstrated how the acoustic signals of crickets occupy a simple 2-dimensional space for song recognition that arises from timing, described by a Gabor function, and time, the integration window. Finally, we discuss the evolution of recognition systems in insects based on simple sensory computations. PMID:25161622

  5. Time Circular Birefringence in Time-Dependent Magnetoelectric Media

    PubMed Central

    Zhang, Ruo-Yang; Zhai, Yan-Wang; Lin, Shi-Rong; Zhao, Qing; Wen, Weijia; Ge, Mo-Lin

    2015-01-01

    Light traveling in time-dependent media has many extraordinary properties which can be utilized to convert frequency, achieve temporal cloaking, and simulate cosmological phenomena. In this paper, we focus on time-dependent axion-type magnetoelectric (ME) media, and prove that light in these media always has two degenerate modes with opposite circular polarizations corresponding to one wave vector , and name this effect “time circular birefringence” (TCB). By interchanging the status of space and time, the pair of TCB modes can appear simultaneously via “time refraction” and “time reflection” of a linear polarized incident wave at a time interface of ME media. The superposition of the two TCB modes causes the “time Faraday effect”, namely the globally unified polarization axes rotate with time. A circularly polarized Gaussian pulse traversing a time interface is also studied. If the wave-vector spectrum of a pulse mainly concentrates in the non-traveling-wave band, the pulse will be trapped with nearly fixed center while its intensity will grow rapidly. In addition, we propose an experimental scheme of using molecular fluid with external time-varying electric and magnetic fields both parallel to the direction of light to realize these phenomena in practice. PMID:26329928

  6. Time Circular Birefringence in Time-Dependent Magnetoelectric Media.

    PubMed

    Zhang, Ruo-Yang; Zhai, Yan-Wang; Lin, Shi-Rong; Zhao, Qing; Wen, Weijia; Ge, Mo-Lin

    2015-01-01

    Light traveling in time-dependent media has many extraordinary properties which can be utilized to convert frequency, achieve temporal cloaking, and simulate cosmological phenomena. In this paper, we focus on time-dependent axion-type magnetoelectric (ME) media, and prove that light in these media always has two degenerate modes with opposite circular polarizations corresponding to one wave vector , and name this effect "time circular birefringence" (TCB). By interchanging the status of space and time, the pair of TCB modes can appear simultaneously via "time refraction" and "time reflection" of a linear polarized incident wave at a time interface of ME media. The superposition of the two TCB modes causes the "time Faraday effect", namely the globally unified polarization axes rotate with time. A circularly polarized Gaussian pulse traversing a time interface is also studied. If the wave-vector spectrum of a pulse mainly concentrates in the non-traveling-wave band, the pulse will be trapped with nearly fixed center while its intensity will grow rapidly. In addition, we propose an experimental scheme of using molecular fluid with external time-varying electric and magnetic fields both parallel to the direction of light to realize these phenomena in practice. PMID:26329928

  7. Hippocampal “Time Cells”: Time versus Path Integration

    PubMed Central

    Kraus, Benjamin J.; Robinson, Robert J.; White, John A.; Eichenbaum, Howard; Hasselmo, Michael E.

    2014-01-01

    SUMMARY Recent studies have reported the existence of hippocampal “time cells,” neurons that fire at particular moments during periods when behavior and location are relatively constant. However, an alternative explanation of apparent time coding is that hippocampal neurons “path integrate” to encode the distance an animal has traveled. Here, we examined hippocampal neuronal firing patterns as rats ran in place on a treadmill, thus “clamping” behavior and location, while we varied the treadmill speed to distinguish time elapsed from distance traveled. Hippocampal neurons were strongly influenced by time and distance, and less so by minor variations in location. Furthermore, the activity of different neurons reflected integration over time and distance to varying extents, with most neurons strongly influenced by both factors and some significantly influenced by only time or distance. Thus, hippocampal neuronal networks captured both the organization of time and distance in a situation where these dimensions dominated an ongoing experience. PMID:23707613

  8. Fractal and natural time analysis of geoelectrical time series

    NASA Astrophysics Data System (ADS)

    Ramirez Rojas, A.; Moreno-Torres, L. R.; Cervantes, F.

    2013-05-01

    In this work we show the analysis of geoelectric time series linked with two earthquakes of M=6.6 and M=7.4. That time series were monitored at the South Pacific Mexican coast, which is the most important active seismic subduction zone in México. The geolectric time series were analyzed by using two complementary methods: a fractal analysis, by means of the detrended fluctuation analysis (DFA) in the conventional time, and the power spectrum defined in natural time domain (NTD). In conventional time we found long-range correlations prior to the EQ-occurrences and simultaneously in NTD, the behavior of the power spectrum suggest the possible existence of seismo electric signals (SES) similar with the previously reported in equivalent time series monitored in Greece prior to earthquakes of relevant magnitude.

  9. GPS Position Time Series @ JPL

    NASA Technical Reports Server (NTRS)

    Owen, Susan; Moore, Angelyn; Kedar, Sharon; Liu, Zhen; Webb, Frank; Heflin, Mike; Desai, Shailen

    2013-01-01

    Different flavors of GPS time series analysis at JPL - Use same GPS Precise Point Positioning Analysis raw time series - Variations in time series analysis/post-processing driven by different users. center dot JPL Global Time Series/Velocities - researchers studying reference frame, combining with VLBI/SLR/DORIS center dot JPL/SOPAC Combined Time Series/Velocities - crustal deformation for tectonic, volcanic, ground water studies center dot ARIA Time Series/Coseismic Data Products - Hazard monitoring and response focused center dot ARIA data system designed to integrate GPS and InSAR - GPS tropospheric delay used for correcting InSAR - Caltech's GIANT time series analysis uses GPS to correct orbital errors in InSAR - Zhen Liu's talking tomorrow on InSAR Time Series analysis

  10. Time Warp Operating System (TWOS)

    NASA Technical Reports Server (NTRS)

    Bellenot, Steven F.

    1993-01-01

    Designed to support parallel discrete-event simulation, TWOS is complete implementation of Time Warp mechanism - distributed protocol for virtual time synchronization based on process rollback and message annihilation.

  11. Time to Talk about CAM

    MedlinePlus

    ... Home Current Issue Past Issues Special Section CAM Time to Talk Past Issues / Winter 2009 Table of ... helps to ensure your coordinated, safe care. NCCAM's Time to Talk program is just right for talking ...

  12. Time, Calendars, and the Millennium.

    ERIC Educational Resources Information Center

    Barron, Daniel D.

    1999-01-01

    Presents a list of resources that focus on the concept of time, telling time, and calendars. Includes nonfiction books for librarians, teachers and older readers; books for younger readers; poems; trivia; Web sites; and search sites. (AEF)

  13. Menopause: Time for a Change

    MedlinePlus

    ... Menopause: Time for a Change Heath and Aging Menopause: Time for a Change Introduction If you are ... this be the start of my transition through menopause? This booklet begins with an explanation of what ...

  14. Circularization time of binary galaxies

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; de Freitas Pacheco, J. A.

    1994-11-01

    We report the results of numerical experiments performed to study the orbital circularization time of binary galaxies. We find that the time scale is quite long (larger than the Hubble time), confirming earlier calculations. The results depend on the initial conditions. From our simulations we obtained a fitting formula for the circularization time as a function of the initial orbital parameters like the pericentric distance, mass ratio, and eccentricity.

  15. Entropy of electromyography time series

    NASA Astrophysics Data System (ADS)

    Kaufman, Miron; Zurcher, Ulrich; Sung, Paul S.

    2007-12-01

    A nonlinear analysis based on Renyi entropy is applied to electromyography (EMG) time series from back muscles. The time dependence of the entropy of the EMG signal exhibits a crossover from a subdiffusive regime at short times to a plateau at longer times. We argue that this behavior characterizes complex biological systems. The plateau value of the entropy can be used to differentiate between healthy and low back pain individuals.

  16. A comment on the use of flushing time, residence time, and age as transport time scales

    USGS Publications Warehouse

    Monsen, N.E.; Cloern, J.E.; Lucas, L.V.; Monismith, Stephen G.

    2002-01-01

    Applications of transport time scales are pervasive in biological, hydrologic, and geochemical studies yet these times scales are not consistently defined and applied with rigor in the literature. We compare three transport time scales (flushing time, age, and residence time) commonly used to measure the retention of water or scalar quantities transported with water. We identify the underlying assumptions associated with each time scale, describe procedures for computing these time scales in idealized cases, and identify pitfalls when real-world systems deviate from these idealizations. We then apply the time scale definitions to a shallow 378 ha tidal lake to illustrate how deviations between real water bodies and the idealized examples can result from: (1) non-steady flow; (2) spatial variability in bathymetry, circulation, and transport time scales; and (3) tides that introduce complexities not accounted for in the idealized cases. These examples illustrate that no single transport time scale is valid for all time periods, locations, and constituents, and no one time scale describes all transport processes. We encourage aquatic scientists to rigorously define the transport time scale when it is applied, identify the underlying assumptions in the application of that concept, and ask if those assumptions are valid in the application of that approach for computing transport time scales in real systems.

  17. Proper-time relativistic dynamics

    NASA Technical Reports Server (NTRS)

    Gill, Tepper L.; Zachary, W. W.; Lindesay, James

    1993-01-01

    Proper-time relativistic single-particle classical Hamiltonian mechanics is formulated using a transformation from observer time to system proper time which is a canonical contact transformation on extended phase space. It is shown that interaction induces a change in the symmetry structure of the system which can be analyzed in terms of a Lie-isotopic deformation of the algebra of observables.

  18. The Fallacy of Timing Methods.

    ERIC Educational Resources Information Center

    Bennett, Jane D.

    1991-01-01

    This article criticizes previously suggested (EC 222 753) objective "timing methods" to help the visually impaired pedestrian determine a safe time to cross an uncontrolled intersection. The assumption that timing the approach of several cars can result in a correct judgment is particularly questioned. (DB)

  19. Consensus on Learning Time Builds

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2008-01-01

    Under enormous pressure to prepare students for a successful future--and fearful that standard school hours do not offer enough time to do so--educators, policymakers, and community activists are adding more learning time to children's lives. Twenty-five years ago, the still-resonant report "A Nation at Risk" urged schools to add more time--an…

  20. Establishing Time for Professional Learning

    ERIC Educational Resources Information Center

    Journal of Staff Development, 2013

    2013-01-01

    Time for collaborative learning is an essential resource for educators working to implement college- and career-ready standards. The pages in this article include tools from the workbook "Establishing Time for Professional Learning." The tools support a complete process to help educators effectively find and use time. The following…

  1. Describing Trails: Distance or Time?

    ERIC Educational Resources Information Center

    Morris, Beverly R.; Bixler, Robert D.

    1998-01-01

    To determine whether trails on visitor maps should indicate distance only or include "time to complete," Cleveland Metroparks interviewed 287 adult visitors to a large regional zoo. The mean perceived "average time to walk a mile" was 17 minutes, but responses ranged from 1.5 to 60 minutes. Half of respondents underestimated the time needed. (SV)

  2. Establishing Time for Professional Learning

    ERIC Educational Resources Information Center

    Killion, Joyce

    2013-01-01

    Finding time for job-embedded professional learning is one of the most frequently cited challenges with implementing the Common Core State Standards (CCSS). With "Establishing Time for Professional Learning," practitioners and education leaders use tools to identify current allocations of time for professional learning, analyze how that…

  3. MISR Center Block Time Tool

    Atmospheric Science Data Center

    2013-04-01

      MISR Center Block Time Tool The misr_time tool calculates the block center times for MISR Level 1B2 files. This is ... version of the IDL package or by using the IDL Virtual Machine application. The IDL Virtual Machine is bundled with IDL and is ...

  4. How Students Spend Their Time.

    ERIC Educational Resources Information Center

    Horne, William R.

    2000-01-01

    Describes a study on time management that involved 57 third-year university students who first estimated, then recorded how they allocated weekly time between work, maintenance (sleep, meals, etc.) and leisure. Finds that students spent a mean of 40 hours per week on schoolwork. Offers suggestions on allocating student time. (Contains 19…

  5. Time Management of Educational Inspectors

    ERIC Educational Resources Information Center

    Göksoy, Süleyman

    2015-01-01

    The aim of the research is to determine the fields that Educational Inspectors have to spare time for and the fields that Educational Inspectors demand to make time for. The data collected by review form was analyzed by content analysis method. According to research results: Educational Inspectors want to make time mostly for counselling and…

  6. The quantum measurement of time

    NASA Technical Reports Server (NTRS)

    Shepard, Scott R.

    1994-01-01

    Traditionally, in non-relativistic Quantum Mechanics, time is considered to be a parameter, rather than an observable quantity like space. In relativistic Quantum Field Theory, space and time are treated equally by reducing space to also be a parameter. Herein, after a brief review of other measurements, we describe a third possibility, which is to treat time as a directly observable quantity.

  7. Bonneville, Power Administration Timing System

    NASA Technical Reports Server (NTRS)

    Martin, Kenneth E.

    1996-01-01

    Time is an integral part of the Bonneville Power Administration's (BPA) operational systems. Generation and power transfers are planned in advance. Utilities coordinate with each other by making these adjustments on a timed schedule. Price varies with demand, so billing is based on time. Outages for maintenance are scheduled to assure they do not interrupt reliable power delivery. Disturbance records are aligned with recorded timetags for analysis and comparison with related information. Advanced applications like traveling wave fault location and real-time phase measurement require continuous timing with high precision. Most of BPA is served by a Central Time System (CTS) at the Dittmer Control Center near Portland, OR. This system keeps time locally and supplies time to both the control center systems and field locations via a microwave signal. It is kept synchronized to national standard time and coordinated with interconnected utilities. It is the official BPA time. Powwer system control and operation is described, followed by a description of BPA timing systems including CTS, the Fault Location Acquisition Reporter, time dissemination, and phasor measurements. References are provided for further reading.

  8. A Note on Time Operators

    NASA Astrophysics Data System (ADS)

    Teranishi, Noriaki

    2016-09-01

    We construct a time operator of a self-adjoint operator H with finite dimensional CCR-domain. As corollaries, we show that there exists a time operator of H with infinite dimensional CCR-domain. Moreover, we construct a time operator of H with dense CCR-domain if there is a complete orthonormal systems which consists of eigenvectors of H.

  9. Time Costs of Mastery Learning.

    ERIC Educational Resources Information Center

    Arlin, Marshall; Webster, Janet

    1983-01-01

    Eighty-eight seventh grade students were randomly assigned to mastery or nonmastery approaches to learning four hierarchical chapters about sailing. The price of increased achievement benefits of group-based mastery learning seems to be increased time costs of (1) extra remedial time and (2) "wasted time" of faster learners. (Author/PN)

  10. Tunneling time in attosecond experiments, intrinsic-type of time. Keldysh, and Mandelstam–Tamm time

    NASA Astrophysics Data System (ADS)

    Kullie, Ossama

    2016-05-01

    Tunneling time in attosecond and strong-field experiments is one of the most controversial issues in current research, because of its importance to the theory of time, the time operator and the time–energy uncertainty relation in quantum mechanics. In Kullie (2015 Phys. Rev. A 92 052118) we derived an estimation of the (real) tunneling time, which shows an excellent agreement with the time measured in attosecond experiments, our derivation is found by utilizing the time–energy uncertainty relation, and it represents a quantum clock. In this work, we show different aspects of the tunneling time in attosecond experiments, we discuss and compare the different views and approaches, which are used to calculate the tunneling time, i.e. Keldysh time (as a real or imaginary quantity), Mandelstam–Tamm time, the classical view of the time measurement and our tunneling time relation(s). We draw some conclusions concerning the validity and the relation between the different types of the tunneling time with the hope that they will help to answer the question put forward by Orlando et al (2014 J. Phys. B 47 204002, 2014 Phys. Rev. A 89 014102): tunneling time, what does it mean? However, as we will see, the important question is a more general one: how to understand the time and the measurement of the time of a quantum system? In respect to our result, the time in quantum mechanics can be, in more general fashion, classified in two types, intrinsic dynamically connected, and external dynamically not connected to the system, and consequently (perhaps only) classical Newtonian time remains as a parametric type of time.

  11. Flexible Timed-Release Encryption

    NASA Astrophysics Data System (ADS)

    Yoshida, Maki; Fujiwara, Toru

    This paper presents a new scheme for Timed-Release Encryption (TRE), which is mainly designed for global use. TRE aims to control the timing of disclosing information. The major approach to TRE assumes that any participants can receive a time token broadcasted by a trusted agent, called a time server. Our scheme is based on this approach and allows participants to generate an encrypted message that can be decrypted using designated or any authenticated time servers including even those which are authenticated after encryption. In this sense, our scheme has a more flexible framework in terms of message decryption.

  12. The LCLS Timing Event System

    SciTech Connect

    Dusatko, John; Allison, S.; Browne, M.; Krejcik, P.; /SLAC

    2012-07-23

    The Linac Coherent Light Source requires precision timing trigger signals for various accelerator diagnostics and controls at SLAC-NAL. A new timing system has been developed that meets these requirements. This system is based on COTS hardware with a mixture of custom-designed units. An added challenge has been the requirement that the LCLS Timing System must co-exist and 'know' about the existing SLC Timing System. This paper describes the architecture, construction and performance of the LCLS timing event system.

  13. The NIST Internet time service

    NASA Technical Reports Server (NTRS)

    Levine, Judah

    1994-01-01

    We will describe the NIST Network Time Service which provides time and frequency information over the Internet. Our first time server is located in Boulder, Colorado, a second backup server is under construction there, and we plan to install a third server on the East Coast later this year. The servers are synchronized to UTC(NIST) with an uncertainty of about 0.8 ms RMS and they will respond to time requests from any client on the Internet in several different formats including the DAYTIME, TIME and NTP protocols. The DAYTIME and TIME protocols are the easiest to use and are suitable for providing time to PC's and other small computers. In addition to UTC(NIST), the DAYTIME message provides advance notice of leap seconds and of the transitions to and from Daylight Saving Time. The Daylight Saving Time notice is based on the US transition dates of the first Sunday in April and the last one in October. The NTP is a more complex protocol that is suitable for larger machines; it is normally run as a 'daemon' process in the background and can keep the time of the client to within a few milliseconds of UTC(NIST). We will describe the operating principles of various kinds of client software ranging from a simple program that queries the server once and sets the local clock to more complex 'daemon' processes (such as NTP) that continuously correct the time of the local clock based on periodic calibrations.

  14. Sensory adaptation for timing perception

    PubMed Central

    Roseboom, Warrick; Linares, Daniel; Nishida, Shin'ya

    2015-01-01

    Recent sensory experience modifies subjective timing perception. For example, when visual events repeatedly lead auditory events, such as when the sound and video tracks of a movie are out of sync, subsequent vision-leads-audio presentations are reported as more simultaneous. This phenomenon could provide insights into the fundamental problem of how timing is represented in the brain, but the underlying mechanisms are poorly understood. Here, we show that the effect of recent experience on timing perception is not just subjective; recent sensory experience also modifies relative timing discrimination. This result indicates that recent sensory history alters the encoding of relative timing in sensory areas, excluding explanations of the subjective phenomenon based only on decision-level changes. The pattern of changes in timing discrimination suggests the existence of two sensory components, similar to those previously reported for visual spatial attributes: a lateral shift in the nonlinear transducer that maps relative timing into perceptual relative timing and an increase in transducer slope around the exposed timing. The existence of these components would suggest that previous explanations of how recent experience may change the sensory encoding of timing, such as changes in sensory latencies or simple implementations of neural population codes, cannot account for the effect of sensory adaptation on timing perception. PMID:25788590

  15. Time-forward speech intelligibility in time-reversed rooms

    PubMed Central

    Longworth-Reed, Laricia; Brandewie, Eugene; Zahorik, Pavel

    2009-01-01

    The effects of time-reversed room acoustics on word recognition abilities were examined using virtual auditory space techniques, which allowed for temporal manipulation of the room acoustics independent of the speech source signals. Two acoustical conditions were tested: one in which room acoustics were simulated in a realistic time-forward fashion and one in which the room acoustics were reversed in time, causing reverberation and acoustic reflections to precede the direct-path energy. Significant decreases in speech intelligibility—from 89% on average to less than 25%—were observed between the time-forward and time-reversed rooms. This result is not predictable using standard methods for estimating speech intelligibility based on the modulation transfer function of the room. It may instead be due to increased degradation of onset information in the speech signals when room acoustics are time-reversed. PMID:19173377

  16. a Structure of Experienced Time

    NASA Astrophysics Data System (ADS)

    Havel, Ivan M.

    2005-10-01

    The subjective experience of time will be taken as a primary motivation for an alternative, essentially discontinuous conception of time. Two types of such experience will be discussed, one based on personal episodic memory, the other on the theoretical fine texture of experienced time below the threshold of phenomenal awareness. The former case implies a discrete structure of temporal episodes on a large scale, while the latter case suggests endowing psychological time with a granular structure on a small scale, i.e. interpreting it as a semi-ordered flow of smeared (not point-like) subliminal time grains. Only on an intermediate temporal scale would the subjectively felt continuity and fluency of time emerge. Consequently, there is no locally smooth mapping of phenomenal time onto the real number continuum. Such a model has certain advantages; for instance, it avoids counterintuitive interpretations of some neuropsychological experiments (e.g. Libet's measurement) in which the temporal order of events is crucial.

  17. Timelines and Quantum Time Operators

    NASA Astrophysics Data System (ADS)

    Moyer, Curt A.

    2015-04-01

    The failure of conventional quantum theory to recognize time as an observable and to admit time operators is addressed. Instead of focusing on the existence of a time operator for a given Hamiltonian, we emphasize the role of the Hamiltonian as the generator of translations in time to construct time states. Taken together, these states constitute what we call a timeline. Such timelines are adequate for the representation of any physical state, and appear to exist even for the semi-bounded and discrete Hamiltonian systems ruled out by Pauli's theorem. However, the step from a timeline to a valid time operator requires additional assumptions that are not always met. Still, this approach illuminates the issues surrounding the construction of time operators, and establishes timelines as legitimate alternatives to the familiar coordinate and momentum bases of standard quantum theory.

  18. Time activities at the BIPM

    NASA Technical Reports Server (NTRS)

    Thomas, Claudine

    1995-01-01

    The generation and dissemination of International Atomic Time, TAI, and of Coordinated Universal Time, UTC, are explicitly mentioned in the list of the principal tasks of the BIPM, recalled in the Comptes Rendus of the 18th Conference Generale des Poids et Mesures, in 1987. These tasks are fulfilled by the BIPM Time Section, thanks to international cooperation with national timing centers, which maintain, under metrological conditions, the clocks used to generate TAI. Besides the current work of data collection and processing, research activities are carried out in order to adapt the computation of TAI to the most recent improvements occurring in the time and frequency domains. Studies concerning the application of general relativity and pulsar timing to time metrology are also actively pursued. This paper summarizes the work done in all these fields and outlines future projects.

  19. Division A Commission 31: Time

    NASA Astrophysics Data System (ADS)

    Hosokawa, Mizuhiko; Arias, Elisa Felicitas; Manchester, Richard; Tuckey, Philip; Matsakis, Demetrios; Zhang, Shougang; Zharov, Vladimir

    2016-04-01

    Time is an essential element of fundamental astronomy. In recent years there have been many time-related issues, in scientific and technological aspects as well as in conventions and definitions. At the Commission 31 (Time) business meeting at the XXIX General Assembly, recent progress and many topics, including Pulsar Time Scales WG and Future UTC WG activities, were reviewed and discussed. In this report, we will review the progress of these topics in the past three years. There are many remarkable topics, such as Time scales, Atomic clock development, Time transfer, Future UTC and future redefinition of the second. Among them, scientific highlights are the progress of pulsar time scales and the optical frequency standards. On the other hand, as the social convention, change in the definition of UTC and the second is important.

  20. Artifacts in digital coincidence timing

    DOE PAGESBeta

    Moses, W. W.; Peng, Q.

    2014-10-16

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into amore » time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator.All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e. the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the 'optimal' method. In conclusion, the purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization.« less

  1. Phase Time and Envelope Time in Time-Distance Analysis and Acoustic Imaging

    NASA Technical Reports Server (NTRS)

    Chou, Dean-Yi; Duvall, Thomas L.; Sun, Ming-Tsung; Chang, Hsiang-Kuang; Jimenez, Antonio; Rabello-Soares, Maria Cristina; Ai, Guoxiang; Wang, Gwo-Ping; Goode Philip; Marquette, William; Ehgamberdiev, Shuhrat; Landenkov, Oleg

    1999-01-01

    Time-distance analysis and acoustic imaging are two related techniques to probe the local properties of solar interior. In this study, we discuss the relation of phase time and envelope time between the two techniques. The location of the envelope peak of the cross correlation function in time-distance analysis is identified as the travel time of the wave packet formed by modes with the same w/l. The phase time of the cross correlation function provides information of the phase change accumulated along the wave path, including the phase change at the boundaries of the mode cavity. The acoustic signals constructed with the technique of acoustic imaging contain both phase and intensity information. The phase of constructed signals can be studied by computing the cross correlation function between time series constructed with ingoing and outgoing waves. In this study, we use the data taken with the Taiwan Oscillation Network (TON) instrument and the Michelson Doppler Imager (MDI) instrument. The analysis is carried out for the quiet Sun. We use the relation of envelope time versus distance measured in time-distance analyses to construct the acoustic signals in acoustic imaging analyses. The phase time of the cross correlation function of constructed ingoing and outgoing time series is twice the difference between the phase time and envelope time in time-distance analyses as predicted. The envelope peak of the cross correlation function between constructed ingoing and outgoing time series is located at zero time as predicted for results of one-bounce at 3 mHz for all four data sets and two-bounce at 3 mHz for two TON data sets. But it is different from zero for other cases. The cause of the deviation of the envelope peak from zero is not known.

  2. Pathophysiological distortions in time perception and timed performance

    PubMed Central

    Allman, Melissa J.

    2012-01-01

    Distortions in time perception and timed performance are presented by a number of different neurological and psychiatric conditions (e.g. Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder and autism). As a consequence, the primary focus of this review is on factors that define or produce systematic changes in the attention, clock, memory and decision stages of temporal processing as originally defined by Scalar Expectancy Theory. These findings are used to evaluate the Striatal Beat Frequency Theory, which is a neurobiological model of interval timing based upon the coincidence detection of oscillatory processes in corticostriatal circuits that can be mapped onto the stages of information processing proposed by Scalar Timing Theory. PMID:21921020

  3. Time Investment and Time Management: An Analysis of Time Students Spend Working at Home for School

    ERIC Educational Resources Information Center

    Wagner, Petra; Schober, Barbara; Spiel, Christiane

    2008-01-01

    This paper deals with the time students spend working at home for school. In Study 1, we investigated amount and regulation of time. Study 2 serves to validate the results of Study 1 and, in addition, investigates the duration of the time units students used and their relation to scholastic success. In Study 1, the participants were 332 students…

  4. A New Theory of Time

    NASA Astrophysics Data System (ADS)

    Langston, Leland

    2016-06-01

    I argue that time cannot pass at the same rate throughout the duration of the universe. Specifically, clocks ran more slowly in the early universe than they do today. We can reasonably ask: "How has time varied with respect to proper time over the life of the universe?" The current Big Bang model of the universe theorizes that the universe began with an infinitely small, hot, dense entity that expanded and cooled over time. In this model, the early universe was infinitely dense, and hence the gravitational field was infinitely strong. This means that clocks ran infinitely more slowly than clocks do today. The obvious question is: What is the relationship of clocks in the early universe with respect to our current clocks? The purpose of this paper is to propose a new theory that attempts to answer this question. This paper shows the theory to be consistent with: (1) Hubble's Law; (2) Gravitational Time Dilation; and (3) The so-called Pioneer Anomaly. A Time Transform pair is introduced that permits time in earlier epocs to be calculated with respect to time in the current epoc (i.e., proper time). Am experiment is proposed to verify the data obtained from the pioneer probe and this proposed theory of time.

  5. The inner experience of time

    PubMed Central

    Wittmann, Marc

    2009-01-01

    The striking diversity of psychological and neurophysiological models of ‘time perception’ characterizes the debate on how and where in the brain time is processed. In this review, the most prominent models of time perception will be critically discussed. Some of the variation across the proposed models will be explained, namely (i) different processes and regions of the brain are involved depending on the length of the processed time interval, and (ii) different cognitive processes may be involved that are not necessarily part of a core timekeeping system but, nevertheless, influence the experience of time. These cognitive processes are distributed over the brain and are difficult to discern from timing mechanisms. Recent developments in the research on emotional influences on time perception, which succeed decades of studies on the cognition of temporal processing, will be highlighted. Empirical findings on the relationship between affect and time, together with recent conceptualizations of self- and body processes, are integrated by viewing time perception as entailing emotional and interoceptive (within the body) states. To date, specific neurophysiological mechanisms that would account for the representation of human time have not been identified. It will be argued that neural processes in the insular cortex that are related to body signals and feeling states might constitute such a neurophysiological mechanism for the encoding of duration. PMID:19487197

  6. Time-resolved photoelectron spectroscopy using synchrotron radiation time structure.

    PubMed

    Bergeard, N; Silly, M G; Krizmancic, D; Chauvet, C; Guzzo, M; Ricaud, J P; Izquierdo, M; Stebel, L; Pittana, P; Sergo, R; Cautero, G; Dufour, G; Rochet, F; Sirotti, F

    2011-03-01

    Synchrotron radiation time structure is becoming a common tool for studying dynamic properties of materials. The main limitation is often the wide time domain the user would like to access with pump-probe experiments. In order to perform photoelectron spectroscopy experiments over time scales from milliseconds to picoseconds it is mandatory to measure the time at which each measured photoelectron was created. For this reason the usual CCD camera-based two-dimensional detection of electron energy analyzers has been replaced by a new delay-line detector adapted to the time structure of the SOLEIL synchrotron radiation source. The new two-dimensional delay-line detector has a time resolution of 5 ns and was installed on a Scienta SES 2002 electron energy analyzer. The first application has been to characterize the time of flight of the photoemitted electrons as a function of their kinetic energy and the selected pass energy. By repeating the experiment as a function of the available pass energy and of the kinetic energy, a complete characterization of the analyzer behaviour in the time domain has been obtained. Even for kinetic energies as low as 10 eV at 2 eV pass energy, the time spread of the detected electrons is lower than 140 ns. These results and the time structure of the SOLEIL filling modes assure the possibility of performing pump-probe photoelectron spectroscopy experiments with the time resolution given by the SOLEIL pulse width, the best performance of the beamline and of the experimental station. PMID:21335912

  7. Make Time To Listen, Take Time To Talk. 15+.

    ERIC Educational Resources Information Center

    Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Center for Mental Health Services.

    Noting that parents and caregivers are vital to the healthy development and growth of children, this pamphlet discusses ways parents and caregivers can help children learn more about themselves and their environment in order to prevent violence. The pamphlet reminds parents to make time to listen to their children and take time to talk with them.…

  8. The Hobart Time Ball and Time Gun: a Critical Review

    NASA Astrophysics Data System (ADS)

    Kinns, Roger

    2011-07-01

    Discussion at the Royal Society in Hobart in 1865 and acoustic experiments in 1868 led to a combined time ball and time gun service in Hobart from March 1875. Complaints from residents led to relocation of the gun a month later, but it was then fired from Queen's Battery in the Domain for half a century. The drop of the ball at Battery Point was always the master signal; the gun was fired when the ball was seen to drop. During the early years, private citizens in Hobart provided the time reference. From September 1886, an electric telegraph signal from Hobart Observatory was used to provide correct time to the ball operator, but signals were of questionable accuracy. During February 1910, the source of the telegraph signal was changed from Hobart Observatory to Melbourne Observatory, but the service was still unreliable and there was pressure to re-equip Hobart Observatory. Finally, automatic dropping of the time ball by telegraph from Melbourne was introduced in November 1910. The time ball service ended in February 1927. The time gun had probably ceased to operate by the end of 1923, but before that date there were sometimes long gaps in the time gun service, particularly on Sundays.

  9. Spouse "Together Time": Quality Time within the Household

    ERIC Educational Resources Information Center

    Glorieux, Ignace; Minnen, Joeri; van Tienoven, Theun Pieter

    2011-01-01

    During the last decade more and more time-use data were gathered on a household level in stead of on an individual level. The time-use information of all members of the household provides much more insight in research fields that until now largely used data gathered at the individual level. One of these research fields is the study of quality of…

  10. Later Education Start Times in Adolescence: Time for Change

    ERIC Educational Resources Information Center

    Kelley, Paul; Lee, Clark

    2015-01-01

    School start times for adolescents in the United States are typically too early to be healthy for this age group. There is significant evidence from the research literature that early starts have serious negative impacts on students. In particular, early education start times in adolescence cause chronic sleep deprivation, which damages both…

  11. Tracking Time Representing Elapsed Time on an Open Timeline

    ERIC Educational Resources Information Center

    Dixon, Juli K.

    2008-01-01

    Elapsed-time problems are notoriously difficult for children. Instruction on techniques for teaching and learning elapsed time is not emphasized in current mathematics education literature. Nor is it addressed in "Curriculum Focal Points for Prekindergarten through Grade 8 Mathematics: A Quest for Coherence" (NCTM 2006). This absence of…

  12. Modern Times: The Industrial Revolution and the Concept of Time.

    ERIC Educational Resources Information Center

    Doppen, Frans H.

    1999-01-01

    Discusses the role the Industrial Revolution had in changing humankind's perception of time and recommends using the flashback approach in order to encourage students to think about how the process of industrialization still affects their lives. Provides activities that address the concept of time caused by the Industrial Revolution. (CMK)

  13. Smart Times: A Parent's Guide to Quality Time with Preschoolers.

    ERIC Educational Resources Information Center

    Burtt, Kent Garland

    Containing over 200 quality time activities for preschool-age children and their parents, "Smart Times" is designed to promote the development of children's physical, social, and cognitive skills and to help parents and children enjoy each other's company more. Recipes for fun and learning are provided to stimulate imagination, promote close…

  14. Pathophysiological Distortions in Time Perception and Timed Performance

    ERIC Educational Resources Information Center

    Allman, Melissa J.; Meck, Warren H.

    2012-01-01

    Distortions in time perception and timed performance are presented by a number of different neurological and psychiatric conditions (e.g. Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder and autism). As a consequence, the primary focus of this review is on factors that define or produce systematic changes in the…

  15. Measuring Time: The Stability of Special Education Teacher Time Use

    ERIC Educational Resources Information Center

    Vannest, Kimberly J.; Parker, Richard I.

    2010-01-01

    Instructional time use is an intervention without equal. The measure of such has clear and important implications for special education practice and research. Although exhortations to maximize instruction and thereby student engagement exist throughout the literature, few studies discuss how special education teachers use their time, and none…

  16. 76 FR 61947 - Timely Mailing Treated as Timely Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ..., 2011 (76 FR 52561), the regulations provide guidance on the proper use of registered or certified mail... FR 52561), the final regulations (TD 9543) contains an error that may prove to be misleading and is... Internal Revenue Service 26 CFR Part 301 RIN 1545-BA99 Timely Mailing Treated as Timely Filing...

  17. 76 FR 62607 - Timely Mailing Treated as Timely Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-11

    ... were the subject of FR Doc. 2011-21416, are corrected as follows: 1. On page 52561, column 1, in the... FR 52561), the final regulations (TD 9543) contains errors that may prove to be misleading and is in... Internal Revenue Service 26 CFR Part 301 RIN 1545-BA99 Timely Mailing Treated as Timely Filing...

  18. Time to the Doctorate: Multilevel Discrete-Time Hazard Analysis

    ERIC Educational Resources Information Center

    Wao, Hesborn O.

    2010-01-01

    Secondary data on 1,028 graduate students nested within 24 programs and admitted into either a Ph. D. or Ed. D. program between 1990 and 2006 at an American public university were used to illustrate the benefits of employing multilevel discrete-time hazard analysis in understanding the timing of doctorate completion in Education and the factors…

  19. VARIABLE TIME-INTERVAL GENERATOR

    DOEpatents

    Gross, J.E.

    1959-10-31

    This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

  20. Reactor control rod timing system

    DOEpatents

    Wu, Peter T. K.

    1982-01-01

    A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

  1. Random time series in astronomy.

    PubMed

    Vaughan, Simon

    2013-02-13

    Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle and over time (usually called light curves by astronomers). In the time domain, we see transient events such as supernovae, gamma-ray bursts and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars and pulsations of stars in nearby galaxies; and we see persistent aperiodic variations ('noise') from powerful systems such as accreting black holes. I review just a few of the recent and future challenges in the burgeoning area of time domain astrophysics, with particular attention to persistently variable sources, the recovery of reliable noise power spectra from sparsely sampled time series, higher order properties of accreting black holes, and time delays and correlations in multi-variate time series. PMID:23277606

  2. [Mathematical model of mental time].

    PubMed

    Glasko, A V; Sadykhova, L G

    2014-01-01

    On the basis of Ernst Mach's ideas and developed before the mathematical theory of mental processes, mathematical definition of duration of an interval of mental time, all over again for perception (experience) of separate event, and then--generally, i.e. for perception (experience) of sequence of events is entered. Its dependence on duration of an appropriating interval of physical time is investigated. Communication of mental time with perception of time (for two cases: "greater" and "small" intervals) is investigated. Comparison of theoretical formulas with results of experimental measurements is spent. Is defined process time which can be used, in particular, as a measure of work. The effect of the inverse of the psychological time, described in works of the Mach is analyzed and modelled. PMID:25723024

  3. Machine-Checkable Timed CSP

    NASA Technical Reports Server (NTRS)

    Goethel, Thomas; Glesner, Sabine

    2009-01-01

    The correctness of safety-critical embedded software is crucial, whereas non-functional properties like deadlock-freedom and real-time constraints are particularly important. The real-time calculus Timed Communicating Sequential Processes (CSP) is capable of expressing such properties and can therefore be used to verify embedded software. In this paper, we present our formalization of Timed CSP in the Isabelle/HOL theorem prover, which we have formulated as an operational coalgebraic semantics together with bisimulation equivalences and coalgebraic invariants. Furthermore, we apply these techniques in an abstract specification with real-time constraints, which is the basis for current work in which we verify the components of a simple real-time operating system deployed on a satellite.

  4. Three-body dwell time

    SciTech Connect

    Kelkar, N. G.

    2010-06-15

    The lifetime of an unstable state or resonance formed as an intermediate state in two-body scattering is known to be related to the dwell time or the time spent within a given region of space by the two interacting particles. This concept is extended to the case of three-body systems and a relation connecting the three-body dwell time with the two-body dwell times of the substructures of the three-body system is derived for the case of separable wave functions. The Kapur-Peierls formalism is revisited to discover one of the first definitions of dwell time in the literature. An extension of the Kapur-Peierls formalism to the three-body case shows that the lifetime of a three-body resonance can indeed be given by the three-body dwell time.

  5. Subsystem real-time time dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Krishtal, Alisa; Ceresoli, Davide; Pavanello, Michele

    2015-04-01

    We present the extension of Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) to real-time Time Dependent Density Functional Theory (rt-TDDFT). FDE is a DFT-in-DFT embedding method that allows to partition a larger Kohn-Sham system into a set of smaller, coupled Kohn-Sham systems. Additional to the computational advantage, FDE provides physical insight into the properties of embedded systems and the coupling interactions between them. The extension to rt-TDDFT is done straightforwardly by evolving the Kohn-Sham subsystems in time simultaneously, while updating the embedding potential between the systems at every time step. Two main applications are presented: the explicit excitation energy transfer in real time between subsystems is demonstrated for the case of the Na4 cluster and the effect of the embedding on optical spectra of coupled chromophores. In particular, the importance of including the full dynamic response in the embedding potential is demonstrated.

  6. A monolithic time stretcher for precision time recording

    SciTech Connect

    Varner, Gary S.

    2007-04-20

    Identifying light mesons which contain only up/down quarks (pions) from those containing a strange quark (kaons) over the typical meter length scales of a particle physics detector requires instrumentation capable of measuring flight times with a resolution on the order of 20ps. In the last few years a large number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have become available. These devices typically have timing resolution performance in the hundreds of ps regime. A technique is presented that is a monolithic version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight system to address this gap between resolution need and intrinsic multi-hit TDC performance.

  7. JPL pulsar timing observations. II - Geocentric arrival times

    NASA Technical Reports Server (NTRS)

    Downs, G. S.; Reichley, P. E.

    1983-01-01

    Monitoring of the behavior of naturally pulsating galactic radio sources, or pulsars, through regularly spaced measurements of pulse arrival times, has been conducted by several laboratories. A tabular presentation is here made of pulse arrival time measurements from the NASA Deep Space Network between late 1968 and early 1981. By expressing the measurements in ephemeris time, and referring them to the geocenter, usable tables of results have been generated for each pulsar listed in the first of the tables given. The considerations addressed by the tables are: (1) a necessary step in the study of pulsar dynamics is the reduction of topocentric arrival times to the barycenter of the solar system; (2) the tabulated data are accessible to all opinions as to the procedures to be used in interpreting arrival time data; and (3) different observing programs can usually be combined to produce an improvement in the total data set.

  8. Permutations and time series analysis.

    PubMed

    Cánovas, Jose S; Guillamón, Antonio

    2009-12-01

    The main aim of this paper is to show how the use of permutations can be useful in the study of time series analysis. In particular, we introduce a test for checking the independence of a time series which is based on the number of admissible permutations on it. The main improvement in our tests is that we are able to give a theoretical distribution for independent time series. PMID:20059199

  9. Timing jitter of Raman solitons.

    PubMed

    Zhou, Gengji; Xin, Ming; Kaertner, Franz X; Chang, Guoqing

    2015-11-01

    We study the relative intensity noise (RIN) and timing jitter of a Raman soliton. We demonstrate that the RIN of an excitation pulse causes center-wavelength fluctuations of the resulting Raman soliton which translates by fiber dispersion into relative timing jitter (RTJ) between the Raman soliton and the excitation pulse. The Raman soliton's absolute timing jitter is dominated by the excitation pulse's timing jitter at low frequency and by the RTJ at high frequency. The experimental study reveals that RTJ can be significantly reduced by reducing the accumulated fiber dispersion (e.g., using less dispersive fibers with shorter length) experienced by the Raman soliton. PMID:26512530

  10. FROG: Time-series analysis

    NASA Astrophysics Data System (ADS)

    Allan, Alasdair

    2014-06-01

    FROG performs time series analysis and display. It provides a simple user interface for astronomers wanting to do time-domain astrophysics but still offers the powerful features found in packages such as PERIOD (ascl:1406.005). FROG includes a number of tools for manipulation of time series. Among other things, the user can combine individual time series, detrend series (multiple methods) and perform basic arithmetic functions. The data can also be exported directly into the TOPCAT (ascl:1101.010) application for further manipulation if needed.

  11. Time transfer using NAVSTAR GPS

    NASA Technical Reports Server (NTRS)

    Vandierendock, A. J.; Hua, Q. D.; Mclean, J. R.; Denz, A. R.

    1982-01-01

    A time transfer unit (TTU) developed for the U.S. Naval Observatory (USNO) has consistently demonstrated the transfer of time with accuracies much better than 100 nanoseconds. A new time transfer system (TTS), the TTS 502 was developed. The TTS 502 is a relatively compact microprocessor-based system with a variety of options that meet each individual's requirements, and has the same performance as the USNO system. The time transfer performance of that USNO system and the details of the new system are presented.

  12. Time ordering of gene coexpression.

    PubMed

    Leng, Xiaoyan; Müller, Hans-Georg

    2006-10-01

    Temporal microarray gene expression profiles allow characterization of gene function through time dynamics of gene coexpression within the same genetic pathway. In this paper, we define and estimate a global time shift characteristic for each gene via least squares, inferred from pairwise curve alignments. These time shift characteristics of individual genes reflect a time ordering that is derived from ob- served temporal gene expression profiles. Once these time shift characteristics are obtained for each gene, they can be entered into further analyses, such as clustering. We illustrate the proposed methodology using Drosophila embryonic development and yeast cell-cycle gene expression profiles, as well as simulations. Feasibility is demonstrated through the successful recovery of time ordering. Estimated time shifts for Drosophila maternal and zygotic genes provide excellent discrimination between these two categories and confirm known genetic pathways through the time order of gene expression. The application to yeast cell-cycle data establishes a natural time order of genes that is in line with cell-cycle phases. The method does not require periodicity of gene expression profiles. Asymptotic justifications are also provided. PMID:16495429

  13. Tempo2: Pulsar Timing Package

    NASA Astrophysics Data System (ADS)

    Hobbs, George; Edwards, Russell

    2012-10-01

    Tempo2 is a pulsar timing package developed to be used both for general pulsar timing applications and also for pulsar timing array research in which data-sets from multiple pulsars need to be processed simultaneously. It was initially developed by George Hobbs and Russell Edwards as part of the Parkes Pulsar Timing Array project. Tempo2 is based on the original Tempo (ascl:1509.002) code and can be used (from the command-line) in a similar fashion. It is very versatile and can be extended by plugins.

  14. Timing calibration and spectral cleaning of LOFAR time series data

    NASA Astrophysics Data System (ADS)

    Corstanje, A.; Buitink, S.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Krause, M.; Nelles, A.; Rachen, J. P.; Schellart, P.; Scholten, O.; ter Veen, S.; Thoudam, S.; Trinh, T. N. G.

    2016-05-01

    We describe a method for spectral cleaning and timing calibration of short time series data of the voltage in individual radio interferometer receivers. It makes use of phase differences in fast Fourier transform (FFT) spectra across antenna pairs. For strong, localized terrestrial sources these are stable over time, while being approximately uniform-random for a sum over many sources or for noise. Using only milliseconds-long datasets, the method finds the strongest interfering transmitters, a first-order solution for relative timing calibrations, and faulty data channels. No knowledge of gain response or quiescent noise levels of the receivers is required. With relatively small data volumes, this approach is suitable for use in an online system monitoring setup for interferometric arrays. We have applied the method to our cosmic-ray data collection, a collection of measurements of short pulses from extensive air showers, recorded by the LOFAR radio telescope. Per air shower, we have collected 2 ms of raw time series data for each receiver. The spectral cleaning has a calculated optimal sensitivity corresponding to a power signal-to-noise ratio of 0.08 (or -11 dB) in a spectral window of 25 kHz, for 2 ms of data in 48 antennas. This is well sufficient for our application. Timing calibration across individual antenna pairs has been performed at 0.4 ns precision; for calibration of signal clocks across stations of 48 antennas the precision is 0.1 ns. Monitoring differences in timing calibration per antenna pair over the course of the period 2011 to 2015 shows a precision of 0.08 ns, which is useful for monitoring and correcting drifts in signal path synchronizations. A cross-check method for timing calibration is presented, using a pulse transmitter carried by a drone flying over the array. Timing precision is similar, 0.3 ns, but is limited by transmitter position measurements, while requiring dedicated flights.

  15. TimeSeer: Scagnostics for high-dimensional time series.

    PubMed

    Dang, Tuan Nhon; Anand, Anushka; Wilkinson, Leland

    2013-03-01

    We introduce a method (Scagnostic time series) and an application (TimeSeer) for organizing multivariate time series and for guiding interactive exploration through high-dimensional data. The method is based on nine characterizations of the 2D distributions of orthogonal pairwise projections on a set of points in multidimensional euclidean space. These characterizations include measures, such as, density, skewness, shape, outliers, and texture. Working directly with these Scagnostic measures, we can locate anomalous or interesting subseries for further analysis. Our application is designed to handle the types of doubly multivariate data series that are often found in security, financial, social, and other sectors. PMID:23307611

  16. Time and foreign exchange markets

    NASA Astrophysics Data System (ADS)

    Berardi, Luca; Serva, Maurizio

    2005-08-01

    The definition of time is still an open question when one deals with high-frequency time series. If time is simply the calendar time, prices can be modeled as continuous random processes and values resulting from transactions or given quotes are discrete samples of this underlying dynamics. On the contrary, if one takes the business time point of view, price dynamics is a discrete random process, and time is simply the ordering according to which prices are quoted in the market. In this paper, we suggest that the business time approach is perhaps a better way of modeling price dynamics than calendar time. This conclusion comes from testing probability densities and conditional variances predicted by the two models against the experimental ones. The data set we use contains the DEM/USD exchange quotes provided to us by Olsen & Associates during a period of one year from January to December 1998. In this period, 1,620,843 quotes entries in the EFX system were recorded.

  17. Sensitivity of ray travel times.

    PubMed

    Smirnov, I. P.; Virovlyansky, A. L.; Zaslavsky, G. M.

    2002-09-01

    Ray in a waveguide can be considered as a trajectory of the corresponding Hamiltonian system, which appears to be chaotic in a nonuniform environment. From the experimental and practical viewpoints, the ray travel time is an important characteristic that, in some way, involves an information about the waveguide condition. It is shown that the ray travel time as a function of the initial momentum and propagation range in the unperturbed waveguide displays a scaling law. Some properties of the ray travel time predicted by this law still persist in periodically nonuniform waveguides with chaotic ray trajectories. As examples we consider few models with special attention to the underwater acoustic waveguide. It is demonstrated for a deep ocean propagation model that even under conditions of ray chaos the ray travel time is determined, to a considerable extent, by the coordinates of the ray endpoints and the number of turning points, i.e., by a topology of the ray path. We show how the closeness of travel times for rays with equal numbers of turning points reveals itself in ray travel time dependencies on the starting momentum and on the depth of the observation point. It has been shown that the same effect is associated with the appearance of the gap between travel times of chaotic and regular rays. The manifestation of the stickiness (the presence of such parts in a chaotic trajectory where the latter exhibits an almost regular behavior) in ray travel times is discussed. (c) 2002 American Institute of Physics. PMID:12779591

  18. Retroactive Adjustment of Perceived Time

    ERIC Educational Resources Information Center

    Patel, Minal; Chait, Maria

    2011-01-01

    Accurately timing acoustic events in dynamic scenes is fundamental to scene analysis. To detect events in busy scenes, listeners must often identify a change in the "pattern" of ongoing fluctuation, resulting in many ubiquitous events being detected later than when they occurred. This raises the question of how delayed detection time affects the…

  19. Time Analysis for Probabilistic Workflows

    SciTech Connect

    Czejdo, Bogdan; Ferragut, Erik M

    2012-01-01

    There are many theoretical and practical results in the area of workflow modeling, especially when the more formal workflows are used. In this paper we focus on probabilistic workflows. We show algorithms for time computations in probabilistic workflows. With time of activities more precisely modeled, we can achieve improvement in the work cooperation and analyses of cooperation including simulation and visualization.

  20. Time Travel in the Library

    ERIC Educational Resources Information Center

    Brown, Donna W.

    2005-01-01

    A Time Travel project in the library gives enthusiasm to students to connect with the past and reinforces their research skills while instilling respect for the past years. The librarian should choose one specific decade to highlight in the library and create an extravaganza that would allow memorabilia from that time period to be located without…

  1. Real-time vision systems

    SciTech Connect

    Johnson, R.; Hernandez, J.E.; Lu, Shin-yee

    1994-11-15

    Many industrial and defence applications require an ability to make instantaneous decisions based on sensor input of a time varying process. Such systems are referred to as `real-time systems` because they process and act on data as it occurs in time. When a vision sensor is used in a real-time system, the processing demands can be quite substantial, with typical data rates of 10-20 million samples per second. A real-time Machine Vision Laboratory (MVL) was established in FY94 to extend our years of experience in developing computer vision algorithms to include the development and implementation of real-time vision systems. The laboratory is equipped with a variety of hardware components, including Datacube image acquisition and processing boards, a Sun workstation, and several different types of CCD cameras, including monochrome and color area cameras and analog and digital line-scan cameras. The equipment is reconfigurable for prototyping different applications. This facility has been used to support several programs at LLNL, including O Division`s Peacemaker and Deadeye Projects as well as the CRADA with the U.S. Textile Industry, CAFE (Computer Aided Fabric Inspection). To date, we have successfully demonstrated several real-time applications: bullet tracking, stereo tracking and ranging, and web inspection. This work has been documented in the ongoing development of a real-time software library.

  2. Instructional Time Trends. Education Trends

    ERIC Educational Resources Information Center

    Woods, Julie Rowland

    2015-01-01

    For more than 30 years, Education Commission of the States has tracked instructional time and frequently receives requests for information about policies and trends. In this Education Trends report, Education Commission of the States addresses some of the more frequent questions, including the impact of instructional time on achievement, variation…

  3. Pedagogy for a Liquid Time

    ERIC Educational Resources Information Center

    Green, Larry; Gary, Kevin

    2016-01-01

    Sociologist Zygmunt Bauman characterizes our time as a time of "liquid modernity" (Bauman in "Liquid modernity." Polity Press, Cambridge, 2000). Rather than settled meanings, categories, and frames of reference Bauman contends that meaning is always in flux, open ended rather than closed. Given Bauman's assessment, pedagogies…

  4. The Time Is Ripe (Again)

    ERIC Educational Resources Information Center

    Barth, Roland S.

    2013-01-01

    "It's always been a promising time for teacher leadership. It's just never been a successful time," writes noted educator Roland Barth. Why? Barth points to five obstacles: administrator resistance, the taboo in teaching against elevating oneself higher than one's peers, the fact that teachers' plates are full, the…

  5. The Variance Reaction Time Model

    ERIC Educational Resources Information Center

    Sikstrom, Sverker

    2004-01-01

    The variance reaction time model (VRTM) is proposed to account for various recognition data on reaction time, the mirror effect, receiver-operating-characteristic (ROC) curves, etc. The model is based on simple and plausible assumptions within a neural network: VRTM is a two layer neural network where one layer represents items and one layer…

  6. Putting time into proof outlines

    NASA Technical Reports Server (NTRS)

    Schneider, Fred B.; Bloom, Bard; Marzullo, Keith

    1991-01-01

    A logic for reasoning about timing of concurrent programs is presented. The logic is based on proof outlines and can handle maximal parallelism as well as resource-constrained execution environments. The correctness proof for a mutual exclusion protocol that uses execution timings in a subtle way illustrates the logic in action.

  7. The Time-Crunch Paradox

    ERIC Educational Resources Information Center

    Gimenez-Nadal, Jose Ignacio; Sevilla-Sanz, Almudena

    2011-01-01

    Previous research has shown little difference in the average leisure time of men and women. This finding is a challenge to the "second shift" argument, which suggests that increases in female labor market hours have not been compensated by equal decreases in household labor. This paper presents time-use and leisure satisfaction data for a variety…

  8. A Matter of Grouchy Time.

    ERIC Educational Resources Information Center

    Burke, Karen; Kelly, M. G. (Peggy)

    1998-01-01

    Presents an activity for identifying patterns in the book "The Grouchy Ladybug" by Eric Carle. The book is appropriate for teaching many concepts including time, developing an alternative story line, and constructing a new book to involve children in thinking about how time passes on a clock as part of exploring patterns. (ASK)

  9. Project TIME. Final Evaluation Report.

    ERIC Educational Resources Information Center

    Schroyer, Connie J.; Payne, David L.

    Project TIME (Training Initiative for Manufacturing Employees) was an 18-month National Workplace Literacy Program conducted by Lord Fairfax Community College in conjunction with an automotive parts plant and Triplett Technical and Business Institute in Virginia. Project TIME had three primary objectives: to help employees obtain the basic…

  10. Learning to Time: A Perspective

    ERIC Educational Resources Information Center

    Machado, Armando; Malheiro, Maria Teresa; Erlhagen, Wolfram

    2009-01-01

    In the last decades, researchers have proposed a large number of theoretical models of timing. These models make different assumptions concerning how animals learn to time events and how such learning is represented in memory. However, few studies have examined these different assumptions either empirically or conceptually. For knowledge to…

  11. CHEMICAL TIME-SERIES SAMPLING

    EPA Science Inventory

    The rationale for chemical time-series sampling has its roots in the same fundamental relationships as govern well hydraulics. Samples of ground water are collected as a function of increasing time of pumpage. The most efficient pattern of collection consists of logarithmically s...

  12. Priming the Mental Time Line

    ERIC Educational Resources Information Center

    Di Bono, Maria Grazia; Casarotti, Marco; Priftis, Konstantinos; Gava, Lucia; Umilta, Carlo; Zorzi, Marco

    2012-01-01

    Growing experimental evidence suggests that temporal events are represented on a mental time line, spatially oriented from left to right. Support for the spatial representation of time comes mostly from studies that have used spatially organized responses. Moreover, many of these studies did not avoid possible confounds attributable to target…

  13. Valuing Time: A Conference Overview

    ERIC Educational Resources Information Center

    Bittman, Michael; Ironmonger, Duncan

    2011-01-01

    The article provides an overview of the development of the field of time use studies. It provides an intellectual history charting the various interests that have shaped the growing applications of this broad social indicator. Recent applications, reflected in this special issue, are (a) interpreting the meaning of leisure, time; (b) the social…

  14. Time Limits and Welfare Use

    ERIC Educational Resources Information Center

    Grogger, Jeffrey

    2004-01-01

    Time limits represent a substantial departure from previous welfare policy. Theory suggests that their effects should vary according to the age of the youngest child of the family. I test this prediction using data from the Current Population Survey and find that time limits indeed have larger effects on families with younger children. I further…

  15. Distribution of tsunami interevent times

    USGS Publications Warehouse

    Geist, E.L.; Parsons, T.

    2008-01-01

    The distribution of tsunami interevent times is analyzed using global and site-specific (Hilo, Hawaii) tsunami catalogs. An empirical probability density distribution is determined by binning the observed interevent times during a period in which the observation rate is approximately constant. The empirical distributions for both catalogs exhibit non-Poissonian behavior in which there is an abundance of short interevent times compared to an exponential distribution. Two types of statistical distributions are used to model this clustering behavior: (1) long-term clustering described by a universal scaling law, and (2) Omori law decay of aftershocks and triggered sources. The empirical and theoretical distributions all imply an increased hazard rate after a tsunami, followed by a gradual decrease with time approaching a constant hazard rate. Examination of tsunami sources suggests that many of the short interevent times are caused by triggered earthquakes, though the triggered events are not necessarily on the same fault.

  16. Space-time quantum imaging

    NASA Astrophysics Data System (ADS)

    Meyers, Ronald E.; Deacon, Keith S.; Tunick, Arnold

    2013-09-01

    We report on an experimental demonstration of quantum imaging where the images are stored in both space and time. Quantum images of remote objects are produced with rotating ground glass induced chaotic laser light and two sensors measuring at different space-time points. Quantum images are observed to move depending on the time delay between the sensor measurements. The experiments provide a new testbed for exploring the time and space scale fundamental physics of quantum imaging and suggest new pathways for quantum information storage and processing. The moved quantum images are in fact new images that are stored in a space-time virtual memory process. The images are stored within the same quantum imaging data sets and thus quantum imaging can produce more information per photon measured than was previously realized.

  17. Abstraction Planning in Real Time

    NASA Technical Reports Server (NTRS)

    Washington, Richard

    1994-01-01

    When a planning agent works in a complex, real-world domain, it is unable to plan for and store all possible contingencies and problem situations ahead of time. The agent needs to be able to fall back on an ability to construct plans at run time under time constraints. This thesis presents a method for planning at run time that incrementally builds up plans at multiple levels of abstraction. The plans are continually updated by information from the world, allowing the planner to adjust its plan to a changing world during the planning process. All the information is represented over intervals of time, allowing the planner to reason about durations, deadlines, and delays within its plan. In addition to the method, the thesis presents a formal model of the planning process and uses the model to investigate planning strategies. The method has been implemented, and experiments have been run to validate the overall approach and the theoretical model.

  18. Time-Warped Geodesic Regression

    PubMed Central

    Hong, Yi; Singh, Nikhil; Kwitt, Roland; Niethammer, Marc

    2016-01-01

    We consider geodesic regression with parametric time-warps. This allows, for example, to capture saturation effects as typically observed during brain development or degeneration. While highly-flexible models to analyze time-varying image and shape data based on generalizations of splines and polynomials have been proposed recently, they come at the cost of substantially more complex inference. Our focus in this paper is therefore to keep the model and its inference as simple as possible while allowing to capture expected biological variation. We demonstrate that by augmenting geodesic regression with parametric time-warp functions, we can achieve comparable flexibility to more complex models while retaining model simplicity. In addition, the time-warp parameters provide useful information of underlying anatomical changes as demonstrated for the analysis of corpora callosa and rat calvariae. We exemplify our strategy for shape regression on the Grassmann manifold, but note that the method is generally applicable for time-warped geodesic regression. PMID:25485368

  19. Time's arrow and Boltzmann's entropy.

    NASA Astrophysics Data System (ADS)

    Lebowitz, J. L.

    For the purpose of this article, the author's motion of time is essentially the Newtonian one - time is real and the basic laws of physics are time reversible, the connect the states of a physical system, possibly of the whole universe, at different instants of time. This of course does not take account of relativity, special or general, and is therefore certainly not the whole story. Still the author believes that the phenomenon they wish to explain, namely the time asymmetric behavior of macroscopic objects, would be for all practical purposes the same in a non-relativistic universe. He therefore focuses here on idealized versions of the problem, in the simplest context, and then sees how far the answers the author gets go towards its solutions.

  20. Perception time and movement time in dolphin pulsing and whistling

    NASA Astrophysics Data System (ADS)

    Ridgway, Sam; Carder, Donald

    2002-05-01

    Auditory/vocal response time was separated into perception time (PT) and movement time (MT) in trials with bottlenose dolphins (Tursiops truncatus)-two males and one female. Pressure catheters accepted into the nasal cavity by each dolphin recorded the pressure increase that preceded sound production. Time from acoustic stimulus onset to onset of pressure rise was recorded as PT (range 57 to 314 ms) and pressure rise onset to dolphin sound onset was recorded as MT (range 63 to 363 ms). Blindfolded dolphins trained to report a target by whistling often responded before completion of their 200- to 800-ms echolocation click trains. Detection of the target, indicated by whistling, before termination of the animal's own click train, suggests that dolphins do not voluntarily respond to each successive click but rather set a rhythm such that each click is emitted about 20 ms after the target echo arrives.

  1. Ensemble vs. time averages in financial time series analysis

    NASA Astrophysics Data System (ADS)

    Seemann, Lars; Hua, Jia-Chen; McCauley, Joseph L.; Gunaratne, Gemunu H.

    2012-12-01

    Empirical analysis of financial time series suggests that the underlying stochastic dynamics are not only non-stationary, but also exhibit non-stationary increments. However, financial time series are commonly analyzed using the sliding interval technique that assumes stationary increments. We propose an alternative approach that is based on an ensemble over trading days. To determine the effects of time averaging techniques on analysis outcomes, we create an intraday activity model that exhibits periodic variable diffusion dynamics and we assess the model data using both ensemble and time averaging techniques. We find that ensemble averaging techniques detect the underlying dynamics correctly, whereas sliding intervals approaches fail. As many traded assets exhibit characteristic intraday volatility patterns, our work implies that ensemble averages approaches will yield new insight into the study of financial markets’ dynamics.

  2. A flexible time recording and time correlation analysis system

    NASA Astrophysics Data System (ADS)

    Shenhav, Nathan J.; Leiferman, Gabriel; Segal, Yitzhak; Notea, Amos

    1983-02-01

    A system was developed to digitize and record the time intervals between detection event pulses, feed to its input channels from a detection device. The accumulated data is transferred continuously in real time to a dise through a PDP 11/34 minicomputer. Even though the system was designed for a specific scope, i.e., the comparative study of passive neutron nondestructive assay methods. It can be characterized by its features as a general purpose time series recorder. The time correlation analysis is performed by software after completion of the data accumulation. The digitizing clock period is selectable and any value, larger than a minimum of 100 ns may be selected. Bursts of up to 128 events with a frequency up to 10 MHz may be recorded. With the present recorder-minicomputer combination, the maximal average recording frequency is 40 kHz.

  3. Real time inverse filter focusing through iterative time reversal.

    PubMed

    Montaldo, Gabriel; Tanter, Mickaël; Fink, Mathias

    2004-02-01

    In order to achieve an optimal focusing through heterogeneous media we need to build the inverse filter of the propagation operator. Time reversal is an easy and robust way to achieve such an inverse filter in nondissipative media. However, as soon as losses appear in the medium, time reversal is not equivalent to the inverse filter anymore. Consequently, it does not produce the optimal focusing and beam degradations may appear. In such cases, we showed in previous works that the optimal focusing can be recovered by using the so-called spatiotemporal inverse filter technique. This process requires the presence of a complete set of receivers inside the medium. It allows one to reach the optimal focusing even in extreme situations such as ultrasonic focusing through human skull or audible sound focusing in strongly reverberant rooms. But, this technique is time consuming and implied fastidious numerical calculations. In this paper we propose a new way to process this inverse filter focusing technique in real time and without any calculation. The new process is based on iterative time reversal process. Contrary to the classical inverse filter technique, this iteration does not require any computation and achieves the inverse filter in an experimental way using wave propagation instead of computational power. The convergence from time reversal to inverse filter during the iterative process is theoretically explained. Finally, the feasibility of this iterative technique is experimentally demonstrated for ultrasound applications. PMID:15000188

  4. Time-symmetrized description of nonunitary time asymmetric quantum evolution

    NASA Astrophysics Data System (ADS)

    Prlina, I. P.; Nedeljković, N. N.

    2016-01-01

    We discuss how systems which evolve manifestly asymmetrically in time can be described within the framework of the time-symmetrized quantum mechanics. An obvious case of asymmetry arises when a pure state evolves into a mixed state via effectively non-unitary evolution. A two-state method for finding the intermediate probability in postselected systems under such evolution is developed and the time-symmetry aspects of the method are explicitly considered. A specific feature is the existence of the so-called second scenario in which the state originating from the postselection measurement evolves under different evolution superoperator than the state from the preselection measurement. The evolution of the second scenario is explicitly defined. We illustrate the method with two characteristic examples: the spontaneous deexcitation of atoms and the systems approaching thermal equilibrium. We consider the systems with two energy levels and calculate the time-symmetrized probability of finding the system in excited state, under general preselection and postselection conditions. The consequences of the asymmetry of the time evolution on this probability are discussed. It is demonstrated that the arrow of time can be reconstructed in some special cases of postselected systems, while, for a general system, this is not the case.

  5. Analysis of the time scales in time periodic Darcy flows

    NASA Astrophysics Data System (ADS)

    Zhu, T.; Waluga, C.; Wohlmuth, B.; Manhart, M.

    2014-12-01

    We investigate unsteady flow in a porous medium under time - periodic (sinusoidal) pressure gradient. DNS were performed to benchmark the analytical solution of the unsteady Darcy equation with two different expressions of the time scale : one given by a consistent volume averaging of the Navier - Stokes equation [1] with a steady state closure for the flow resistance term, another given by volume averaging of the kinetic energy equation [2] with a closure for the dissipation rate . For small and medium frequencies, the analytical solutions with the time scale obtained by the energy approach compare well with the DNS results in terms of amplitude and phase lag. For large frequencies (f > 100 [Hz]) we observe a slightly smaller damping of the amplitude. This study supports the use of the unsteady form of Darcy's equation with constant coefficients to solve time - periodic Darcy flows at low and medium frequencies. Our DNS simulations, however, indicate that the time scale predicted by the VANS approach together with a steady - state closure for the flow resistance term is too small. The one obtained by the energy approach matches the DNS results well. At large frequencies, the amplitudes deviate slightly from the analytical solution of the unsteady Darcy equation. Note that at those high frequencies, the flow amplitudes remain below 1% of those of steady state flow. This result indicates that unsteady porous media flow can approximately be described by the unsteady Darcy equation with constant coefficients for a large range of frequencies, provided, the proper time scale has been found.

  6. The manifold definitions of time

    PubMed Central

    Oestreicher, Christian

    2012-01-01

    We are unable, using our five senses, to feel time, nor, using our intelligence, to define it, because we stand inexorably within time. We achieve a representation of time through evaluation of changes in ourselves and in our environment. This is made possible by memory functions. What if time only existed as a construct in our minds, and what if the absence of this construct made our mode of thinking uncomfortable to us? If our two major tools for constructing our world, feeling and reasoning, are of little help, then the study of time, ie, chronology, might exist as a list of scientific hypotheses, and remain, to some extent, a philosophical question—an enigma that has been approached by thinkers for more than two millenia. In this review, various fields of knowledge are discussed in relation to time, from philosophy and physics to psychology and biology. We discuss the differences between Chronos and Tempus, respectively the time of physicists and that of psychologists. PMID:23393419

  7. Blade tip timing (BTT) uncertainties

    NASA Astrophysics Data System (ADS)

    Russhard, Pete

    2016-06-01

    Blade Tip Timing (BTT) is an alternative technique for characterising blade vibration in which non-contact timing probes (e.g. capacitance or optical probes), typically mounted on the engine casing (figure 1), and are used to measure the time at which a blade passes each probe. This time is compared with the time at which the blade would have passed the probe if it had been undergoing no vibration. For a number of years the aerospace industry has been sponsoring research into Blade Tip Timing technologies that have been developed as tools to obtain rotor blade tip deflections. These have been successful in demonstrating the potential of the technology, but rarely produced quantitative data, along with a demonstration of a traceable value for measurement uncertainty. BTT technologies have been developed under a cloak of secrecy by the gas turbine OEM's due to the competitive advantages it offered if it could be shown to work. BTT measurements are sensitive to many variables and there is a need to quantify the measurement uncertainty of the complete technology and to define a set of guidelines as to how BTT should be applied to different vehicles. The data shown in figure 2 was developed from US government sponsored program that bought together four different tip timing system and a gas turbine engine test. Comparisons showed that they were just capable of obtaining measurement within a +/-25% uncertainty band when compared to strain gauges even when using the same input data sets.

  8. Regularly timed events amid chaos.

    PubMed

    Blakely, Jonathan N; Cooper, Roy M; Corron, Ned J

    2015-11-01

    We show rigorously that the solutions of a class of chaotic oscillators are characterized by regularly timed events in which the derivative of the solution is instantaneously zero. The perfect regularity of these events is in stark contrast with the well-known unpredictability of chaos. We explore some consequences of these regularly timed events through experiments using chaotic electronic circuits. First, we show that a feedback loop can be implemented to phase lock the regularly timed events to a periodic external signal. In this arrangement the external signal regulates the timing of the chaotic signal but does not strictly lock its phase. That is, phase slips of the chaotic oscillation persist without disturbing timing of the regular events. Second, we couple the regularly timed events of one chaotic oscillator to those of another. A state of synchronization is observed where the oscillators exhibit synchronized regular events while their chaotic amplitudes and phases evolve independently. Finally, we add additional coupling to synchronize the amplitudes, as well, however in the opposite direction illustrating the independence of the amplitudes from the regularly timed events. PMID:26651759

  9. The manifold definitions of time.

    PubMed

    Oestreicher, Christian

    2012-12-01

    We are unable, using our five senses, to feel time, nor, using our intelligence, to define it, because we stand inexorably within time. We achieve a representation of time through evaluation of changes in ourselves and in our environment. This is made possible by memory functions. What if time only existed as a construct in our minds, and what if the absence of this construct made our mode of thinking uncomfortable to us? If our two major tools for constructing our world, feeling and reasoning, are of little help, then the study of time, ie, chronology, might exist as a list of scientific hypotheses, and remain, to some extent, a philosophical question--an enigma that has been approached by thinkers for more than two millenia. In this review, various fields of knowledge are discussed in relation to time, from philosophy and physics to psychology and biology. We discuss the differences between Chronos and Tempus, respectively the time of physicists and that of psychologists. PMID:23393419

  10. Chronotype, bed timing and total sleep time in seniors

    PubMed Central

    Monk, Timothy H.; Buysse, Daniel J.

    2014-01-01

    Many older adults (seniors) experience problems with getting enough sleep. Because of the link between sleep and circadian rhythms, changes in bedtime lead to changes in the amount of sleep obtained. Although primarily determined genetically, chronotype changes with advancing age towards a more morning-type (M-type) orientation. In a 2006 study, we have found a linear relationship, by which the earlier a senior’s bedtime, the more sleep she/he will obtain. The aim of this study was to see whether this relationship differs for M-type seniors, as compared to seniors outside the M-type category. Retired seniors (n = 954, 535 M, 410F, 65 years+, mean age 74.4 years) taking part in a telephone interview were divided into M-types and Other types (O-types) using the Composite Scale of Morningness (CSM). The relationship between bedtime and Total Sleep Time (TST), and between rise-time and TST, was tested using linear regression separately for M-types and O-types. For each participant, habitual bedtime, rise-time and total Sleep Time (TST) [after removing time spent in unwanted wakefulness] were obtained using a telephone version of the Sleep Timing Questionnaire (STQ). Both chronotype groups showed a significant linear relationship between bedtime and TST (p<0.001); with earlier bedtimes leading to more TST (M-type 5.6 min; O-type 4.4 min per 10 min change [slope difference p = 0.05]); and an opposite relationship between rise-time and TST with earlier rise-times leading to less TST (M-type 6.7 min; O-type 4.2 min per 10 min change [slope difference p 0.001]). M-types retired to bed 56 min earlier (p<0.001), awoke 93 min earlier (p<0.001) and obtained 23 min less TST (p<0.001) than O-types. In conclusion, both chronotypes showed TST to be related in a linear way to bedtime and rise-time; the overall shorter TST in M-types was due to them rising 93 min earlier, but only retiring to bed 56 min earlier than O-types; as well as having a steeper rise-time versus TST

  11. Real-time flutter identification

    NASA Technical Reports Server (NTRS)

    Roy, R.; Walker, R.

    1985-01-01

    The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

  12. Time series with tailored nonlinearities

    NASA Astrophysics Data System (ADS)

    Räth, C.; Laut, I.

    2015-10-01

    It is demonstrated how to generate time series with tailored nonlinearities by inducing well-defined constraints on the Fourier phases. Correlations between the phase information of adjacent phases and (static and dynamic) measures of nonlinearities are established and their origin is explained. By applying a set of simple constraints on the phases of an originally linear and uncorrelated Gaussian time series, the observed scaling behavior of the intensity distribution of empirical time series can be reproduced. The power law character of the intensity distributions being typical for, e.g., turbulence and financial data can thus be explained in terms of phase correlations.

  13. Stingray: Spectral-timing software

    NASA Astrophysics Data System (ADS)

    Huppenkothen, Daniela; Bachetti, Matteo; Stevens, Abigail L.; Migliari, Simone; Balm, Paul

    2016-08-01

    Stingray is a spectral-timing software package for astrophysical X-ray (and more) data. The package merges existing efforts for a (spectral-)timing package in Python and is composed of a library of time series methods (including power spectra, cross spectra, covariance spectra, and lags); scripts to load FITS data files from different missions; a simulator of light curves and event lists that includes different kinds of variability and more complicated phenomena based on the impulse response of given physical events (e.g. reverberation); and a GUI to ease the learning curve for new users.

  14. Time-Critical Volume Rendering

    NASA Technical Reports Server (NTRS)

    Kaufman, Arie

    1998-01-01

    For the past twelve months, we have conducted and completed a joint research entitled "Time- Critical Volume Rendering" with NASA Ames. As expected, High performance volume rendering algorithms have been developed by exploring some new faster rendering techniques, including object presence acceleration, parallel processing, and hierarchical level-of-detail representation. Using our new techniques, initial experiments have achieved real-time rendering rates of more than 10 frames per second of various 3D data sets with highest resolution. A couple of joint papers and technique reports as well as an interactive real-time demo have been compiled as the result of this project.

  15. Time delay in molecular photoionization

    NASA Astrophysics Data System (ADS)

    Hockett, P.; Frumker, E.; Villeneuve, D. M.; Corkum, P. B.

    2016-05-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitrogen and carbon monoxide. We present energy and angle-resolved maps of the Wigner delay time for single-photon valence ionization, and discuss the possibilities for experimental measurements.

  16. Time series with tailored nonlinearities.

    PubMed

    Räth, C; Laut, I

    2015-10-01

    It is demonstrated how to generate time series with tailored nonlinearities by inducing well-defined constraints on the Fourier phases. Correlations between the phase information of adjacent phases and (static and dynamic) measures of nonlinearities are established and their origin is explained. By applying a set of simple constraints on the phases of an originally linear and uncorrelated Gaussian time series, the observed scaling behavior of the intensity distribution of empirical time series can be reproduced. The power law character of the intensity distributions being typical for, e.g., turbulence and financial data can thus be explained in terms of phase correlations. PMID:26565155

  17. Contacts of space--times

    SciTech Connect

    Maia, M.D.

    1981-03-01

    The concept of contact between manifolds is applied to space--times of general relativity. For a given background space--time a contact approximation of second order is defined and interpreted both from the point of view of a metric pertubation and of a higher order tangent manifold. In the first case, an application to the high frequency gravitational wave hypothesis is suggested. In the second case, a constant curvature tangent bundle is constructed and suggested as a means to define a ten parameter local space--time symmetry.

  18. Theoretical analysis of the modal behavior of 2D random photonic crystals

    NASA Astrophysics Data System (ADS)

    Hamada, Shimpei; Takeda, Seiji; Viktorovitch, Pierre; Obara, Minoru

    2012-03-01

    We present the effect of structural randomness on the formation of Anderson localization (AL) in random photonic crystals (RPCs) by using a two-dimensional FDTD (Finite-Difference Time-Domain) computational method. The RPC consists of a silicon substrate with an array of air holes aligned in a triangular lattice shape. The structural randomness is introduced by randomly dislocating the positions of air holes. By investigating impulse response of the system, we obtained frequency spectra and Q-factors of long-lived modes. The modal characteristics of the modes as a function of structural randomness in RPCs and optimization of the structural randomness to achieve high photon confinement efficiency are achieved.

  19. RPC detector characteristics and performance for INO-ICAL experiment

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Gaur, A.; Hasbuddin, Md.; Naimuddin, Md.

    2016-03-01

    The India-based Neutrino Observatory (INO) is an approved multi-institutional collaboration neutrino physics project, aimed at building an underground laboratory in the southern India. INO will utilize a large magnetized Iron Calorimeter (ICAL) detector to study the atmospheric neutrinos, and to explore the unresolved issues related to neutrinos. The Resistive Plate Chambers (RPCs), interleaved in between iron absorber layers, are going to be used as the active signal readouts for the ICAL experiment at INO. The research and development is carried out to find structural quality and electrical response for RPC electrode materials available within local domain. The assembled 2 mm gap RPCs are tested using cosmic muons for their detection performance. The study also incorporates preliminary results on detector timing and signal induced charge measurements.

  20. Dedicated clock/timing-circuit theories of time perception and timed performance.

    PubMed

    van Rijn, Hedderik; Gu, Bon-Mi; Meck, Warren H

    2014-01-01

    Scalar Timing Theory (an information-processing version of Scalar Expectancy Theory) and its evolution into the neurobiologically plausible Striatal Beat-Frequency (SBF) theory of interval timing are reviewed. These pacemaker/accumulator or oscillation/coincidence detection models are then integrated with the Adaptive Control of Thought-Rational (ACT-R) cognitive architecture as dedicated timing modules that are able to make use of the memory and decision-making mechanisms contained in ACT-R. The different predictions made by the incorporation of these timing modules into ACT-R are discussed as well as the potential limitations. Novel implementations of the original SBF model that allow it to be incorporated into ACT-R in a more fundamental fashion than the earlier simulations of Scalar Timing Theory are also considered in conjunction with the proposed properties and neural correlates of the "internal clock". PMID:25358706

  1. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2007-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  2. Time, Frequency and Physical Measurement.

    ERIC Educational Resources Information Center

    Hellwig, Helmut; And Others

    1978-01-01

    Describes several developments in atomic clocks and frequency standards pointing out the feasibility and practicality in adopting a unified standard of time and frequency to replace other base standards of length, mass, and temperature. (GA)

  3. Real-time refinery optimization

    SciTech Connect

    Kennedy, J.P.

    1989-05-01

    This article discusses refinery operation with specific consideration of the topics of: gasoline; control projects; catalytic reforming control; hydrocracker control packages; blending optimization; real-time data acquisition; and other plant automation packages.

  4. A-3 Construction Time Lapse

    NASA Technical Reports Server (NTRS)

    2009-01-01

    A time lapse from start to finish of steel erection for the 235-foot tall A-3 Test Stand. Ground work for the stand was broken in August 2008 and the final structural steel beam was placed April 9, 2009.

  5. TIME-INTERVAL MEASURING DEVICE

    DOEpatents

    Gross, J.E.

    1958-04-15

    An electronic device for measuring the time interval between two control pulses is presented. The device incorporates part of a previous approach for time measurement, in that pulses from a constant-frequency oscillator are counted during the interval between the control pulses. To reduce the possible error in counting caused by the operation of the counter gating circuit at various points in the pulse cycle, the described device provides means for successively delaying the pulses for a fraction of the pulse period so that a final delay of one period is obtained and means for counting the pulses before and after each stage of delay during the time interval whereby a plurality of totals is obtained which may be averaged and multplied by the pulse period to obtain an accurate time- Interval measurement.

  6. Time discounting and criminal behavior.

    PubMed

    Åkerlund, David; Golsteyn, Bart H H; Grönqvist, Hans; Lindahl, Lena

    2016-05-31

    One of the most basic predictions of almost any model of crime is that individual time preferences matter. However, empirical evidence on this fundamental property is essentially nonexistent. To our knowledge, this paper provides the first pieces of evidence on the link between time discounting and crime. We use a unique dataset that combines a survey-based measure of time discount rates (at age 13) with detailed longitudinal register data on criminal behavior spanning over 18 y. Our results show that individuals with short time horizons have a significantly higher risk of criminal involvement later in life. The magnitude of the relationship is substantial and corresponds to roughly one-third of the association between intelligence and crime. PMID:27185950

  7. Sensitivity of Pulsar Timing Arrays

    NASA Astrophysics Data System (ADS)

    Siemens, Xavier

    2015-08-01

    For the better part of the last decade, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been using the Green Bank and Arecibo radio telescopes to monitor millisecond pulsars. NANOGrav, along with similar international collaborations, the European Pulsar Timing Array and the Parkes Pulsar Timing Array in Australia, form a consortium of consortia: the International Pulsar Timing Array (IPTA). The goal of the IPTA is to directly detect low-frequency gravitational waves which cause small changes to the times of arrival of radio pulses from millisecond pulsars. In this talk I will discuss the work of NANOGrav and the IPTA as well as our sensitivity to gravitational waves from astrophysical sources. I will show that a detection is possible by the end of the decade.

  8. Engine ignition timing control apparatus

    SciTech Connect

    Takahashi, N.

    1988-03-01

    An apparatus for controlling the timing of ignition of an internal combustion engine including at least one cylinder is described comprising: sensor means sensitive to combustion pressure in the cylinder for providing a sensor signal indicative of a sensed cylinder combustion pressure; and a control circuit including means coupled to the sensor means for measuring a crankshaft angle at which the cylinder combustion pressure is at maximum, means for retarding the ignition timing in response to the measured crankshaft angle being less than a first value, means for retaining the ignition timing in response to the measured crankshaft angle being between the first and a second value greater than the first value, and means for advancing the ignition timing in response to the measured crankshaft angle being greater than the second value.

  9. Time discounting and criminal behavior

    PubMed Central

    Åkerlund, David; Golsteyn, Bart H. H.; Grönqvist, Hans; Lindahl, Lena

    2016-01-01

    One of the most basic predictions of almost any model of crime is that individual time preferences matter. However, empirical evidence on this fundamental property is essentially nonexistent. To our knowledge, this paper provides the first pieces of evidence on the link between time discounting and crime. We use a unique dataset that combines a survey-based measure of time discount rates (at age 13) with detailed longitudinal register data on criminal behavior spanning over 18 y. Our results show that individuals with short time horizons have a significantly higher risk of criminal involvement later in life. The magnitude of the relationship is substantial and corresponds to roughly one-third of the association between intelligence and crime. PMID:27185950

  10. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2006-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  11. Pattern Recognition in Time Series

    NASA Astrophysics Data System (ADS)

    Lin, Jessica; Williamson, Sheri; Borne, Kirk D.; DeBarr, David

    2012-03-01

    Perhaps the most commonly encountered data types are time series, touching almost every aspect of human life, including astronomy. One obvious problem of handling time-series databases concerns with its typically massive size—gigabytes or even terabytes are common, with more and more databases reaching the petabyte scale. For example, in telecommunication, large companies like AT&T produce several hundred millions long-distance records per day [Cort00]. In astronomy, time-domain surveys are relatively new—these are surveys that cover a significant fraction of the sky with many repeat observations, thereby producing time series for millions or billions of objects. Several such time-domain sky surveys are now completed, such as the MACHO [Alco01],OGLE [Szym05], SDSS Stripe 82 [Bram08], SuperMACHO [Garg08], and Berkeley’s Transients Classification Pipeline (TCP) [Star08] projects. The Pan-STARRS project is an active sky survey—it began in 2010, a 3-year survey covering three-fourths of the sky with ˜60 observations of each field [Kais04]. The Large Synoptic Survey Telescope (LSST) project proposes to survey 50% of the visible sky repeatedly approximately 1000 times over a 10-year period, creating a 100-petabyte image archive and a 20-petabyte science database (http://www.lsst.org/). The LSST science database will include time series of over 100 scientific parameters for each of approximately 50 billion astronomical sources—this will be the largest data collection (and certainly the largest time series database) ever assembled in astronomy, and it rivals any other discipline’s massive data collections for sheer size and complexity. More common in astronomy are time series of flux measurements. As a consequence of many decades of observations (and in some cases, hundreds of years), a large variety of flux variations have been detected in astronomical objects, including periodic variations (e.g., pulsating stars, rotators, pulsars, eclipsing binaries

  12. Time-dependent drift Hamiltonian

    SciTech Connect

    Boozer, A.H.

    1983-03-01

    The lowest-order drift equations are given in a canonical magnetic coordinate form for time-dependent magnetic and electric fields. The advantages of the canonical Hamiltonian form are also discussed.

  13. Does iris change over time?

    PubMed

    Mehrotra, Hunny; Vatsa, Mayank; Singh, Richa; Majhi, Banshidhar

    2013-01-01

    Iris as a biometric identifier is assumed to be stable over a period of time. However, some researchers have observed that for long time lapse, the genuine match score distribution shifts towards the impostor score distribution and the performance of iris recognition reduces. The main purpose of this study is to determine if the shift in genuine scores can be attributed to aging or not. The experiments are performed on the two publicly available iris aging databases namely, ND-Iris-Template-Aging-2008-2010 and ND-TimeLapseIris-2012 using a commercial matcher, VeriEye. While existing results are correct about increase in false rejection over time, we observe that it is primarily due to the presence of other covariates such as blur, noise, occlusion, and pupil dilation. This claim is substantiated with quality score comparison of the gallery and probe pairs. PMID:24244305

  14. Monolithic time-to-amplitude converter for photon timing applications

    NASA Astrophysics Data System (ADS)

    Resnati, D.; Rech, I.; Ghioni, M.; Cova, S.

    2009-05-01

    In the last years Time-Correlated Single-Photon Counting (TCSPC) has increasingly been used in many different scientific applications (e.g.: single molecule spectroscopy, fluorescence lifetime imaging, diffuse optical tomography). Many of these applications are calling for new requests on the development of instrumentation that operates at higher and higher conversion rates and that is able to resolve optical signals not only in the time domain, but also in wavelength, polarization and position. To exploit the potential of parallel analysis over multiple acquisition channels, a new generation of TCSPC devices is needed that is characterized by low size and costs. The core block of TCSPC instrumentation is the time-interval measurement section, which can be implemented with a Time-to-Amplitude Converter (TAC); the converter can be integrated on a single chip in order to reduce the overall size and cost of the system. This paper presents a monolithic TAC that has been designed to achieve the high resolution, good differential linearity and fast counting rate required in modern applications. The TAC here described is built on a commercial 0.35 μm CMOS technology, and is characterized by resolution better than 60 ps, differential nonlinearity limited to 0.5% rms and short dead-time of 80 ns. The low area occupation (1.4x1.8 mm) and minimal need for external components allow the realization of very compact instruments with multiple acquisition channels operating simultaneously at very high count rates.

  15. A perspective on time: Loss frequencies, time scales, and lifetimes

    NASA Astrophysics Data System (ADS)

    Prather, Michael; Holmes, Christopher

    2013-04-01

    The need to describe the Earth system and its components with a quantity that has units of time is ubiquitous since the 1970s work of Bolin, Rodhe and Junge. These quantities are often used as metrics of the system to describe the duration or cumulative impact of an action, such as in global-warming and ozone-depletion potentials, as in the SPARC lifetime re-assessment. The quantity designated "lifetime" is often calculated inconsistently and/or misused when applied to the subsequent evaluations of impacts. A careful set of definitions and derivations is needed to ensure that we are reporting, publishing, and comparing the same quantities. There are many different ways to derive metrics of time, and they describe different properties of the system. Here we carefully define several of those metrics - denoted here as loss frequency, time scale, and lifetime - and demonstrate which properties of the system they describe. Three generalizable examples demonstrate (i) how the non-linear chemistry of tropospheric ozone makes simple approaches for tracking pollution in error; (ii) why the lifetime of a gas depends on the history of emissions, and (iii) when multiple reservoirs generate time scales quite separate from the traditionally defined lifetime. Proper use of the many "time" parameters in a system, however, gives a very powerful understanding of the response to anthropogenic perturbations.

  16. Neural mechanisms of timing control in a coincident timing task.

    PubMed

    Masaki, Hiroaki; Sommer, Werner; Takasawa, Noriyoshi; Yamazaki, Katuo

    2012-04-01

    Many ball sports such as tennis or baseball require precise temporal anticipation of both sensory input and motor output (i.e., receptor anticipation and effector anticipation, respectively) and close performance monitoring. We investigated the neural mechanisms underlying timing control and performance monitoring in a coincident timing task involving both types of anticipations. Peak force for two time-to-peak force (TTP) conditions-recorded with a force-sensitive key-was required to coincide with a specific position of a stimulus rotating either slow or fast on a clock face while the contingent negative variation (CNV) and the motor-elicited negativity were recorded. Absolute timing error was generally smaller for short TTP (high velocity) conditions. CNV amplitudes increased with both faster stimulus velocity and longer TTPs possibly reflecting increased motor programming efforts. In addition, the motor-elicited negativity was largest in the slow stimulus/short TTP condition, probably representing some forms of performance monitoring as well as shorter response duration. Our findings indicate that the coincident timing task is a good model for real-life situations of tool use. PMID:22415201

  17. Real-time fractal signal processing in the time domain

    NASA Astrophysics Data System (ADS)

    Hartmann, András; Mukli, Péter; Nagy, Zoltán; Kocsis, László; Hermán, Péter; Eke, András

    2013-01-01

    Fractal analysis has proven useful for the quantitative characterization of complex time series by scale-free statistical measures in various applications. The analysis has commonly been done offline with the signal being resident in memory in full length, and the processing carried out in several distinct passes. However, in many relevant applications, such as monitoring or forecasting, algorithms are needed to capture changes in the fractal measure real-time. Here we introduce real-time variants of the Detrended Fluctuation Analysis (DFA) and the closely related Signal Summation Conversion (SSC) methods, which are suitable to estimate the fractal exponent in one pass. Compared to offline algorithms, the precision is the same, the memory requirement is significantly lower, and the execution time depends on the same factors but with different rates. Our tests show that dynamic changes in the fractal parameter can be efficiently detected. We demonstrate the applicability of our real-time methods on signals of cerebral hemodynamics acquired during open-heart surgery.

  18. System-time entanglement in a discrete-time model

    NASA Astrophysics Data System (ADS)

    Boette, A.; Rossignoli, R.; Gigena, N.; Cerezo, M.

    2016-06-01

    We present a model of discrete quantum evolution based on quantum correlations between the evolving system and a reference quantum clock system. A quantum circuit for the model is provided, which in the case of a constant Hamiltonian is able to represent the evolution over 2n time steps in terms of just n time qubits and n control gates. We then introduce the concept of system-time entanglement as a measure of distinguishable quantum evolution, based on the entanglement between the system and the reference clock. This quantity vanishes for stationary states and is maximum for systems jumping onto a new orthogonal state at each time step. In the case of a constant Hamiltonian leading to a cyclic evolution it is a measure of the spread over distinct energy eigenstates and satisfies an entropic energy-time uncertainty relation. The evolution of mixed states is also examined. Analytical expressions for the basic case of a qubit clock, as well as for the continuous limit in the evolution between two states, are provided.

  19. Subsystem real-time time dependent density functional theory.

    PubMed

    Krishtal, Alisa; Ceresoli, Davide; Pavanello, Michele

    2015-04-21

    We present the extension of Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) to real-time Time Dependent Density Functional Theory (rt-TDDFT). FDE is a DFT-in-DFT embedding method that allows to partition a larger Kohn-Sham system into a set of smaller, coupled Kohn-Sham systems. Additional to the computational advantage, FDE provides physical insight into the properties of embedded systems and the coupling interactions between them. The extension to rt-TDDFT is done straightforwardly by evolving the Kohn-Sham subsystems in time simultaneously, while updating the embedding potential between the systems at every time step. Two main applications are presented: the explicit excitation energy transfer in real time between subsystems is demonstrated for the case of the Na4 cluster and the effect of the embedding on optical spectra of coupled chromophores. In particular, the importance of including the full dynamic response in the embedding potential is demonstrated. PMID:25903875

  20. Putting time into proof outlines

    NASA Technical Reports Server (NTRS)

    Schneider, Fred B.; Bloom, Bard; Marzullo, Keith

    1993-01-01

    A logic for reasoning about timing properties of concurrent programs is presented. The logic is based on Hoare-style proof outlines and can handle maximal parallelism as well as certain resource-constrained execution environments. The correctness proof for a mutual exclusion protocol that uses execution timings in a subtle way illustrates the logic in action. A soundness proof using structural operational semantics is outlined in the appendix.

  1. Time-resolved molecular imaging

    NASA Astrophysics Data System (ADS)

    Xu, Junliang; Blaga, Cosmin I.; Agostini, Pierre; DiMauro, Louis F.

    2016-06-01

    Time-resolved molecular imaging is a frontier of ultrafast optical science and physical chemistry. In this article, we review present and future key spectroscopic and microscopic techniques for ultrafast imaging of molecular dynamics and show their differences and connections. The advent of femtosecond lasers and free electron x-ray lasers bring us closer to this goal, which eventually will extend our knowledge about molecular dynamics to the attosecond time domain.

  2. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Muratore, John F.

    1991-01-01

    Lessons learned from operational real time expert systems are examined. The basic system architecture is discussed. An expert system is any software that performs tasks to a standard that would normally require a human expert. An expert system implies knowledge contained in data rather than code. And an expert system implies the use of heuristics as well as algorithms. The 15 top lessons learned by the operation of a real time data system are presented.

  3. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Heindel, Troy A.

    1991-01-01

    Information is given in viewgraph form on the Real Time Data System (RTDS). The goals are to increase the quality of flight decision making, reduce and enhance flight controller training time, and serve as a near-operations technology test-bed. Information is given on the growth of RTDS; flight control disciplines; RTDS technology deployment in 1987-1989 and 1990-91; a functionality comparison of mainframes and workstations; and technology transfer activities.

  4. Feedback control of waiting times

    NASA Astrophysics Data System (ADS)

    Brandes, Tobias; Emary, Clive

    2016-04-01

    Feedback loops are known as a versatile tool for controlling transport in small systems, which usually have large intrinsic fluctuations. Here we investigate the control of a temporal correlation function, the waiting-time distribution, under active and passive feedback conditions. We develop a general formalism and then specify to the simple unidirectional transport model, where we compare costs of open-loop and feedback control and use methods from optimal control theory to optimize waiting-time distributions.

  5. Feedback control of waiting times.

    PubMed

    Brandes, Tobias; Emary, Clive

    2016-04-01

    Feedback loops are known as a versatile tool for controlling transport in small systems, which usually have large intrinsic fluctuations. Here we investigate the control of a temporal correlation function, the waiting-time distribution, under active and passive feedback conditions. We develop a general formalism and then specify to the simple unidirectional transport model, where we compare costs of open-loop and feedback control and use methods from optimal control theory to optimize waiting-time distributions. PMID:27176250

  6. Geothermal Exploration Cost and Time

    DOE Data Explorer

    Jenne, Scott

    2013-02-13

    The Department of Energy’s Geothermal Technology Office (GTO) provides RD&D funding for geothermal exploration technologies with the goal of lowering the risks and costs of geothermal development and exploration. The National Renewable Energy Laboratory (NREL) was tasked with developing a metric in 2012 to measure the impacts of this RD&D funding on the cost and time required for exploration activities. The development of this cost and time metric included collecting cost and time data for exploration techniques, creating a baseline suite of exploration techniques to which future exploration cost and time improvements can be compared, and developing an online tool for graphically showing potential project impacts (all available at http://en.openei.org/wiki/Gateway: Geothermal). This paper describes the methodology used to define the baseline exploration suite of techniques (baseline), as well as the approach that was used to create the cost and time data set that populates the baseline. The resulting product, an online tool for measuring impact, and the aggregated cost and time data are available on the Open Energy Information website (OpenEI, http://en.openei.org) for public access. - Published 01/01/2013 by US National Renewable Energy Laboratory NREL.

  7. TCES. Time Card Entry System

    SciTech Connect

    Montierth, B.

    1996-05-01

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two week payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual`s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.

  8. Cover times of random searches

    NASA Astrophysics Data System (ADS)

    Chupeau, Marie; Bénichou, Olivier; Voituriez, Raphaël

    2015-10-01

    How long must one undertake a random search to visit all sites of a given domain? This time, known as the cover time, is a key observable to quantify the efficiency of exhaustive searches, which require a complete exploration of an area and not only the discovery of a single target. Examples range from immune-system cells chasing pathogens to animals harvesting resources, from robotic exploration for cleaning or demining to the task of improving search algorithms. Despite its broad relevance, the cover time has remained elusive and so far explicit results have been scarce and mostly limited to regular random walks. Here we determine the full distribution of the cover time for a broad range of random search processes, including Lévy strategies, intermittent strategies, persistent random walks and random walks on complex networks, and reveal its universal features. We show that for all these examples the mean cover time can be minimized, and that the corresponding optimal strategies also minimize the mean search time for a single target, unambiguously pointing towards their robustness.

  9. Symbolic planning with metric time

    NASA Astrophysics Data System (ADS)

    MacMillan, T. R.

    1992-03-01

    Most AI planning systems have considered time in a qualitative way only. For example, a plan may require one action to come 'before' another. Metric time enables AI planners to represent action durations and reason over quantitative temporal constraints such as windows of opportunity. This paper presents preliminary results observed while developing a theory of multi-agent adversarial planning for battle management research. Quantitative temporal reasoning seems essential in this domain. For example, Orange may plan to block Blue's attack by seizing a river ford which Blue must cross, but only if Orange can get there during the window of opportunity while Blue is approaching the ford but has not yet arrived. In nonadversarial multi-agent planning, metric time enables planners to detect windows of opportunity for agents to help or hinder each other. In single-agent planning, metric time enables planners to reason about deadlines, temporally constrained resource availability, and asynchronous processes which the agent can initiate and monitor. Perhaps surprisingly, metric time increases the computational complexity of planning less than might be expected, because it reduces the computational complexity of modal truth criteria. To make this observation precise, we review Chapman's analysis to modal truth criteria and describe a tractable heuristic criterion, 'worst case necessarily true.' Deciding if a proposition is worst case necessarily true, in a single-agent plan with n steps, requires O(n) computations only if qualitative temporal information is used. We show how it can be decided in O(log n) using metric time.

  10. Time Delay of CGM Sensors

    PubMed Central

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  11. Neurocomputational models of time perception.

    PubMed

    Hass, Joachim; Durstewitz, Daniel

    2014-01-01

    Mathematical modeling is a useful tool for understanding the neurodynamical and computational mechanisms of cognitive abilities like time perception, and for linking neurophysiology to psychology. In this chapter, we discuss several biophysical models of time perception and how they can be tested against experimental evidence. After a brief overview on the history of computational timing models, we list a number of central psychological and physiological findings that such a model should be able to account for, with a focus on the scaling of the variability of duration estimates with the length of the interval that needs to be estimated. The functional form of this scaling turns out to be predictive of the underlying computational mechanism for time perception. We then present four basic classes of timing models (ramping activity, sequential activation of neuron populations, state space trajectories and neural oscillators) and discuss two specific examples in more detail. Finally, we review to what extent existing theories of time perception adhere to the experimental constraints. PMID:25358705

  12. Reduction in maximum time uncertainty of paired time signals

    DOEpatents

    Theodosiou, G.E.; Dawson, J.W.

    1983-10-04

    Reduction in the maximum time uncertainty (t[sub max]--t[sub min]) of a series of paired time signals t[sub 1] and t[sub 2] varying between two input terminals and representative of a series of single events where t[sub 1][<=]t[sub 2] and t[sub 1]+t[sub 2] equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t[sub min]) of the first signal t[sub 1] closer to t[sub max] and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20--800. 6 figs.

  13. Reduction in maximum time uncertainty of paired time signals

    DOEpatents

    Theodosiou, G.E.; Dawson, J.W.

    1981-02-11

    Reduction in the maximum time uncertainty (t/sub max/ - t/sub min/) of a series of paired time signals t/sub 1/ and t/sub 2/ varying between two input terminals and representative of a series of single events where t/sub 1/ less than or equal to t/sub 2/ and t/sub 1/ + t/sub 2/ equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t/sub min/) of the first signal t/sub 1/ closer to t/sub max/ and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20 to 800.

  14. Reduction in maximum time uncertainty of paired time signals

    DOEpatents

    Theodosiou, George E.; Dawson, John W.

    1983-01-01

    Reduction in the maximum time uncertainty (t.sub.max -t.sub.min) of a series of paired time signals t.sub.1 and t.sub.2 varying between two input terminals and representative of a series of single events where t.sub.1 .ltoreq.t.sub.2 and t.sub.1 +t.sub.2 equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t.sub.min) of the first signal t.sub.1 closer to t.sub.max and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20-800.

  15. Time sequence and time scale of intermediate mass fragment emission

    SciTech Connect

    De Filippo, E.; Pagano, A.; Cardella, G.; Lanzano, G.; Papa, M.; Pirrone, S.; Politi, G.; Wilczynski, J.

    2005-04-01

    Semiperipheral collisions in the {sup 124}Sn+{sup 64}Ni reaction at 35 MeV/nucleon were studied using the forward part of the Charged Heavy Ion Mass and Energy Resolving Array. Nearly completely determined ternary events involving projectilelike fragments (PLF), targetlike fragments (TLF), and intermediate mass fragments (IMF) were selected. A new method of studying the reaction mechanism, focusing on the analysis of the correlations between relative velocities in the IMF+PLF and IMF+TLF subsystems, is proposed. The relative velocity correlations provide information on the time sequence and time scale of the neck fragmentation processes leading to production of IMFs. It is shown that the majority of light IMFs are produced within 40-80 fm/c after the system starts to reseparate. Heavy IMFs are formed at times of about 120 fm/c or later and can be viewed as resulting from two-step (sequential) neck rupture processes.

  16. Noninertial coordinate time: A new concept affecting time standards, time transfers, and clock synchronization

    NASA Technical Reports Server (NTRS)

    Deines, Steven D.

    1992-01-01

    Relativity compensations must be made in precise and accurate measurements whenever an observer is accelerated. Although many believe the Earth-centered frame is sufficiently inertial, accelerations of the Earth, as evidenced by the tides, prove that it is technically a noninertial system for even an Earth-based observer. Using the constant speed of light, a set of fixed remote clocks in an inertial frame can be synchronized to a fixed master clock transmitting its time in that frame. The time on the remote clock defines the coordinate time at that coordinate position. However, the synchronization procedure for an accelerated frame is affected, because the distance between the master and remote clocks is altered due to the acceleration of the remote clock toward or away from the master clock during the transmission interval. An exact metric that converts observations from noninertial frames to inertial frames was recently derived. Using this metric with other physical relationships, a new concept of noninertial coordinate time is defined. This noninertial coordinate time includes all relativity compensations. This new issue raises several timekeeping issues, such as proper time standards, time transfer process, and clock synchronization, all in a noninertial frame such as Earth.

  17. Emotional Time, Creativity and Consciousness:. on Time Experience in Depression

    NASA Astrophysics Data System (ADS)

    Emrich, Hinderk M.; Dietrich, Detlef D.

    2005-10-01

    Emotionality of subjective time-experience in depressed patients is related to the concept of Michael Theunissen as to the dominance of the past in relation to the spontaneity of the subject within a present moment of time. Electrophysiological measurements, using event-related potentials point to the view that negative emotions can induce a value-related cognitive/emotional blockade of valuation processes. The role of creativity to overcome such memory-related impairments is discussed within the context of possible functions of consciousness.

  18. On time scales and time synchronization using LORAN-C as a time reference signal

    NASA Technical Reports Server (NTRS)

    Chi, A. R.

    1974-01-01

    The long term performance of the eight LORAN-C chains is presented in terms of the Coordinated Universal Time (UTC) of the U.S. Naval Observatory (USNO); and the use of the LORAN-C navigation system for maintaining the user's clock to a UTC scale is described. The atomic time scale and the UTC of several national laboratories and observatories relative to the international atomic time are reported. Typical performance of several NASA tracking station clocks, relative to the USNO master clock, is also presented.

  19. Loran-C time management

    NASA Technical Reports Server (NTRS)

    Justice, Charles; Mason, Norm; Taggart, Doug

    1994-01-01

    As of 1 Oct. 1993, the US Coast Guard (USCG) supports and operates fifteen Loran-C chains. With the introduction of the Global Positioning Systems (GPS) and the termination of the Department of Defense (DOD) overseas need for Loran-C, the USCG will cease operating the three remaining overseas chains by 31 Dec. 1994. Following this date, the USCG Loran-C system will consist of twelve chains. Since 1971, management of time synchronization of the Loran-C system has been conducted under a Memorandum of Agreement between the US Naval Observatory (USNO) and the USCG. The requirement to maintain synchronization with Coordinated Universal Time (UTC) was initially specified as +/- 25 microseconds. This tolerance was rapidly lowered to +/- 2.5 microseconds in 1974. To manage this synchronization requirement, the USCG incorporated administrative practices which kept the USNO appraised of all aspects of the master timing path. This included procedures for responding to timing path failures, timing adjustments, and time steps. Conducting these aspects of time synchronization depended on message traffic between the various master stations and the USNO. To determine clock adjustment the USCG relied upon the USNO's Series 4 and 100 updates so that the characteristics of the master clock could be plotted and controls appropriately applied. In 1987, Public Law 100-223, under the Airport and Airway Improvement Act Amendment, reduced the synchronization tolerance to approximately 100 nanoseconds for chains serving the National Airspace System (NAS). This action caused changes in the previous administrative procedures and techniques. The actions taken by the USCG to meet the requirements of this law are presented.

  20. Probabilistic Survivability Versus Time Modeling

    NASA Technical Reports Server (NTRS)

    Joyner, James J., Sr.

    2015-01-01

    This technical paper documents Kennedy Space Centers Independent Assessment team work completed on three assessments for the Ground Systems Development and Operations (GSDO) Program to assist the Chief Safety and Mission Assurance Officer (CSO) and GSDO management during key programmatic reviews. The assessments provided the GSDO Program with an analysis of how egress time affects the likelihood of astronaut and worker survival during an emergency. For each assessment, the team developed probability distributions for hazard scenarios to address statistical uncertainty, resulting in survivability plots over time. The first assessment developed a mathematical model of probabilistic survivability versus time to reach a safe location using an ideal Emergency Egress System at Launch Complex 39B (LC-39B); the second used the first model to evaluate and compare various egress systems under consideration at LC-39B. The third used a modified LC-39B model to determine if a specific hazard decreased survivability more rapidly than other events during flight hardware processing in Kennedys Vehicle Assembly Building (VAB).Based on the composite survivability versus time graphs from the first two assessments, there was a soft knee in the Figure of Merit graphs at eight minutes (ten minutes after egress ordered). Thus, the graphs illustrated to the decision makers that the final emergency egress design selected should have the capability of transporting the flight crew from the top of LC 39B to a safe location in eight minutes or less. Results for the third assessment were dominated by hazards that were classified as instantaneous in nature (e.g. stacking mishaps) and therefore had no effect on survivability vs time to egress the VAB. VAB emergency scenarios that degraded over time (e.g. fire) produced survivability vs time graphs that were line with aerospace industry norms.

  1. Time, temporality, now. Experiencing time and concepts of time in an interdisciplinary perspective. Lectures.

    NASA Astrophysics Data System (ADS)

    Atmanspacher, H.; Ruhnau, E.

    The essays in this topical volume inquire into one of the most fundamental issues of philosophy and the cognitive and natural sciences: the riddle of time. The central feature is the tension between the experience and the conceptualization of time, reflecting an apparently unavoidable antinomy of subjective first-person accounts and objective traditional science. Is time based in the physics of inanimate matter, or does it originate in the operation of our minds? Is it essential for the constitution of reality, or is it just an illusion? Issues of time, temporality, and nowness are paradigms for interdisciplinary work in many contemporary fields of research. The authors of this volume discuss profoundly the mutual relationships and inspiring perspectives. They address a general audience with academic background knowledge.

  2. Divided Timed and Continuous Timed Assessment Protocols and Academic Performance

    ERIC Educational Resources Information Center

    Perucca, David.

    2013-01-01

    Children from a low socioeconomic status (SES) are exposed to numerous stress factors that are negatively associated with sustained attention and academic performance. This association suggests that the timed component of lengthy assessments may be unfair for students from such backgrounds, as they may have an inability to sustain attention during…

  3. Negotiating Time: The Significance of Timing in Ending Inpatient Work

    ERIC Educational Resources Information Center

    Jones, Sarah Gustavus

    2007-01-01

    This paper discusses work with young people during their stay on an NHS psychiatric inpatient unit, especially focusing on the end of treatment and the appropriate timing of discharge into the community. When approaching the end of an admission, various factors are considered that seem particularly relevant to the decision of when a young person…

  4. A Matter of Time: The Effects of Time on Learning

    ERIC Educational Resources Information Center

    Kidd, Debra

    2014-01-01

    This article looks at how time might be viewed differently in the classroom, drawing on the philosophy of Gilles Deleuze in order to frame the exploration. It asks how teachers might become more attuned to difference, uncertainty and possibility in their classrooms and questions the wisdom of viewing the learning process in linear ways. The…

  5. Social Trust, Social Partner Time and Television Time

    ERIC Educational Resources Information Center

    Patulny, Roger

    2011-01-01

    Social trust is an important phenomenon, but the influence of important time-based measures upon trust has not been examined. Such measures include social contact and anti-social activity, such as television watching, which allows for the co-presence of other people. This paper reports on associations between trust and weighted means of co-present…

  6. Time-of-flight measurements

    SciTech Connect

    Atwood, W.B.

    1980-10-01

    Time of flight (TOF) measurements are used in high energy particle physics experiments to: (1) distinguish background from events and (2) identify particle types. An example of background separation is shown. These data come from a coincidence electro-production experiment performed at SLAC. The reaction being studied was e + p ..-->.. e' + p' + X where the e(p) stand for an initial and detected electron (proton) and X is a produced but undetected final state with a mass in the rho meson region. The relative time between the detection of an electron and a proton in two of the spectrometers in End Station A is plotted. Data for two different kinematic settings taken in the experiment are shown. The time resolution has been partially corrected for the various flight paths through the instruments and the difference in time resolutions between the two settings results mainly from the incompleteness of this correction. The signal height above the background depends on the time resolution, ..delta.. tau. The chance background is proportional to the product of the electron counting rate, the proton counting rate, and ..delta.. tau. Smaller ..delta.. tau means that higher electron and proton counting rates may be tolerated and result in a similar signal-to-noise ratio.

  7. Spatialization of Time in Mian

    PubMed Central

    Fedden, Sebastian; Boroditsky, Lera

    2012-01-01

    We examine representations of time among the Mianmin of Papua New Guinea. We begin by describing the patterns of spatial and temporal reference in Mian. Mian uses a system of spatial terms that derive from the orientation and direction of the Hak and Sek rivers and the surrounding landscape. We then report results from a temporal arrangement task administered to a group of Mian speakers. The results reveal evidence for a variety of temporal representations. Some participants arranged time with respect to their bodies (left to right or toward the body). Others arranged time as laid out on the landscape, roughly along the east/west axis (either east to west or west to east). This absolute pattern is consistent both with the axis of the motion of the sun and the orientation of the two rivers, which provides the basis for spatial reference in the Mian language. The results also suggest an increase in left to right temporal representations with increasing years of formal education (and the reverse pattern for absolute spatial representations for time). These results extend previous work on spatial representations for time to a new geographical region, physical environment, and linguistic and cultural system. PMID:23181037

  8. The Parkes Pulsar Timing Array

    NASA Astrophysics Data System (ADS)

    Manchester, Richard N.

    2015-08-01

    The Parkes Pulsar Timing Array (PPTA) project uses the Parkes 64-m radio telescope to observe 22 millisecond pulsars in three bands: 40cm (band centre 732 MHz), 20cm (1369 MHz) and 10cm (3100 MHz). Coherent de-dispersion systems are used for the 40cm and 20cm bands and digital polyphase filterbanks are used for the 20cm and 10cm bands. Observations are made at intervals of two to three weeks and observations times for each pulsar in each band are typically one hour. Regular PPTA observations commenced in early 2005 but earlier timing data, primarily in the 20cm band, exist for many of the pulsars back to 1994. Pipeline processing scripts are based on PSRCHIVE routines and take into account instrumental offsets. Timing analyses include modelling of dispersion variations and red and white noise in the data. The primary scientific goal of the PPTA project is the detection of gravitational waves, either a stochastic background from supermassive black-hole binary systems in distant galaxies or from individual binary systems. The PPTA data sets have many other applications including establishment of a pulsar-based timescale, improvement of solar-system ephemerides and studies of the individual pulsars. PPTA data sets have been made available to the International Pulsar Timing Array consortium and analysis of the combined data sets is progressing. Recent developments, both instrumental and science-related, will be described.

  9. Extreme times for volatility processes

    NASA Astrophysics Data System (ADS)

    Masoliver, Jaume; Perelló, Josep

    2007-04-01

    Extreme times techniques, generally applied to nonequilibrium statistical mechanical processes, are also useful for a better understanding of financial markets. We present a detailed study on the mean first-passage time for the volatility of return time series. The empirical results extracted from daily data of major indices seem to follow the same law regardless of the kind of index thus suggesting an universal pattern. The empirical mean first-passage time to a certain level L is fairly different from that of the Wiener process showing a dissimilar behavior depending on whether L is higher or lower than the average volatility. All of this indicates a more complex dynamics in which a reverting force drives volatility toward its mean value. We thus present the mean first-passage time expressions of the most common stochastic volatility models whose approach is comparable to the random diffusion description. We discuss asymptotic approximations of these models and confront them to empirical results with a good agreement with the exponential Ornstein-Uhlenbeck model.

  10. Relaxation times estimation in MRI

    NASA Astrophysics Data System (ADS)

    Baselice, Fabio; Caivano, Rocchina; Cammarota, Aldo; Ferraioli, Giampaolo; Pascazio, Vito

    2014-03-01

    Magnetic Resonance Imaging is a very powerful techniques for soft tissue diagnosis. At the present, the clinical evaluation is mainly conducted exploiting the amplitude of the recorded MR image which, in some specific cases, is modified by using contrast enhancements. Nevertheless, spin-lattice (T1) and spin-spin (T2) relaxation times can play an important role in many pathology diagnosis, such as cancer, Alzheimer or Parkinson diseases. Different algorithms for relaxation time estimation have been proposed in literature. In particular, the two most adopted approaches are based on Least Squares (LS) and on Maximum Likelihood (ML) techniques. As the amplitude noise is not zero mean, the first one produces a biased estimator, while the ML is unbiased but at the cost of high computational effort. Recently the attention has been focused on the estimation in the complex, instead of the amplitude, domain. The advantage of working with real and imaginary decomposition of the available data is mainly the possibility of achieving higher quality estimations. Moreover, the zero mean complex noise makes the Least Square estimation unbiased, achieving low computational times. First results of complex domain relaxation times estimation on real datasets are presented. In particular, a patient with an occipital lesion has been imaged on a 3.0T scanner. Globally, the evaluation of relaxation times allow us to establish a more precise topography of biologically active foci, also with respect to contrast enhanced images.

  11. Japanese Virtual Observatory (JVO) Prototype 2

    NASA Astrophysics Data System (ADS)

    Tanaka, M.; Shirasaki, Y.; Honda, S.; Mizumoto, Y.; Ohishi, M.; Yasuda, N.; Masunaga, Y.; Ishihara, Y.; Abe, K.; Tsutsumi, J.; Nakamoto, H.; Kobayashi, Y.; Yoshida, T.; Morita, Y.

    2005-12-01

    We describe the architecture of the Japanese Virtual Observatory (JVO) prototype system version 2. JVO aims at seamless access to astronomical data archives stored in distributed data servers as well as data analysis environment. For this purpose, it is important to establish a framework for access to remote servers, including remote procedure calls (RPCs) and data transfer. A data request for distributed database is described in the JVO Query Language. The JVO system parses the query language and decomposes it into individual remote procedures, such as the retrieval of catalog images and spectra, cross matching, and workflow generation. Based on this workflow, remote procedures are called. For RPCs of JVO prototype system 1, we employed Globus toolkit 2 (GT2). However, latency time of GT2 RPCs was too long for successive short-time jobs. Therefore, we employed Globus toolkit 3 (GT3) for JVO prototype system 2. As a result, we find that Grid Service in GT3 improves performance of RPC. In addition to Grid Service, Reliable File Transfer (RFT) is used for efficient data transfer. Astronomical data stored in distributed servers are discovered through a registry server which provides metadata discussed in the IVOA registry working group and is built using a XML database.

  12. No Time for Dead Time: Timing Analysis of Bright Black Hole Binaries with NuSTAR

    NASA Astrophysics Data System (ADS)

    Bachetti, Matteo; Harrison, Fiona A.; Cook, Rick; Tomsick, John; Schmid, Christian; Grefenstette, Brian W.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Fabian, Andrew C.; Fürst, Felix; Gandhi, Poshak; Hailey, Charles J.; Kara, Erin; Maccarone, Thomas J.; Miller, Jon M.; Pottschmidt, Katja; Stern, Daniel; Uttley, Phil; Walton, Dominic J.; Wilms, Jörn; Zhang, William W.

    2015-02-01

    Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time per event is relatively long (~2.5 msec) and varies event-to-event by a few percent. The most obvious effect is a distortion of the white noise level in the power density spectrum (PDS) that cannot be easily modeled with standard techniques due to the variable nature of the dead time. In this paper, we show that it is possible to exploit the presence of two completely independent focal planes and use the cospectrum, the real part of the cross PDS, to obtain a good proxy of the white-noise-subtracted PDS. Thereafter, one can use a Monte Carlo approach to estimate the remaining effects of dead time, namely, a frequency-dependent modulation of the variance and a frequency-independent drop of the sensitivity to variability. In this way, most of the standard timing analysis can be performed, albeit with a sacrifice in signal-to-noise ratio relative to what would be achieved using more standard techniques. We apply this technique to NuSTAR observations of the black hole binaries GX 339-4, Cyg X-1, and GRS 1915+105.

  13. Time delay and distance measurement

    NASA Technical Reports Server (NTRS)

    Abshire, James B. (Inventor); Sun, Xiaoli (Inventor)

    2011-01-01

    A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

  14. Bruise chromophore concentrations over time

    NASA Astrophysics Data System (ADS)

    Duckworth, Mark G.; Caspall, Jayme J.; Mappus, Rudolph L., IV; Kong, Linghua; Yi, Dingrong; Sprigle, Stephen H.

    2008-03-01

    During investigations of potential child and elder abuse, clinicians and forensic practitioners are often asked to offer opinions about the age of a bruise. A commonality between existing methods of bruise aging is analysis of bruise color or estimation of chromophore concentration. Relative chromophore concentration is an underlying factor that determines bruise color. We investigate a method of chromophore concentration estimation that can be employed in a handheld imaging spectrometer with a small number of wavelengths. The method, based on absorbance properties defined by Beer-Lambert's law, allows estimation of differential chromophore concentration between bruised and normal skin. Absorption coefficient data for each chromophore are required to make the estimation. Two different sources of this data are used in the analysis- generated using Independent Component Analysis and taken from published values. Differential concentration values over time, generated using both sources, show correlation to published models of bruise color change over time and total chromophore concentration over time.

  15. Recovery times of riparian vegetation

    NASA Astrophysics Data System (ADS)

    Vesipa, R.; Camporeale, C.; Ridolfi, L.

    2016-04-01

    Riparian vegetation is a key element in a number of processes that determine the ecogeomorphological features of the river landscape. Depending on the river water stage fluctuations, vegetation biomass randomly switches between growth and degradation phases and exhibits relevant temporal variations. A full understanding of vegetation dynamics is therefore only possible if the hydrological stochastic forcing is considered. In this vein, we focus on the recovery time of vegetation, namely the typical time taken by vegetation to recover a well-developed state starting from a low biomass value (induced, for instance, by an intense flood). The analytical expression of the plot-dependent recovery time is given, the role of hydrological and biological parameters is discussed, and the impact of river-induced randomness is highlighted. Finally, the effect of man-induced hydrological changes (e.g., river damming or climate changes) is explored.

  16. Synchronization by small time delays

    NASA Astrophysics Data System (ADS)

    Pruessner, G.; Cheang, S.; Jensen, H. J.

    2015-02-01

    Synchronization is a phenomenon observed in all of the living and in much of the non-living world, for example in the heart beat, Huygens' clocks, the flashing of fireflies and the clapping of audiences. Depending on the number of degrees of freedom involved, different mathematical approaches have been used to describe it, most prominently integrate-and-fire oscillators and the Kuramoto model of coupled oscillators. In the present work, we study a very simple and general system of smoothly evolving oscillators, which continue to interact even in the synchronized state. We find that under very general circumstances, synchronization generically occurs in the presence of a (small) time delay. Strikingly, the synchronization time is inversely proportional to the time delay.

  17. Time representations in social science

    PubMed Central

    Schulz, Yvan

    2012-01-01

    Time has long been a major topic of study in social science, as in other sciences or in philosophy. Social scientists have tended to focus on collective representations of time, and on the ways in which these representations shape our everyday experiences. This contribution addresses work from such disciplines as anthropology, sociology and history. It focuses on several of the main theories that have preoccupied specialists in social science, such as the alleged “acceleration” of life and overgrowth of the present in contemporary Western societies, or the distinction between so-called linear and circular conceptions of time. The presentation of these theories is accompanied by some of the critiques they have provoked, in order to enable the reader to form her or his own opinion of them. PMID:23393420

  18. Abstraction Planning in Real Time

    NASA Technical Reports Server (NTRS)

    Washington, R.

    1994-01-01

    When a planning agent works in a complex, real-world domain, it is unable to plan for and store all possible contingencies and problem situations ahead of time. This thesis presents a method for planning a run time that incrementally builds up plans at multiple levels of abstraction. The plans are continually updated by information from the world, allowing the planner to adjust its plan to a changing world during the planning process. All the information is represented over intervals of time, allowing the planner to reason about durations, deadlines, and delays within its plan. In addition to the method, the thesis presents a formal model of the planning process and uses the model to investigate planning strategies.

  19. Advertising emergency department wait times.

    PubMed

    Weiner, Scott G

    2013-03-01

    Advertising emergency department (ED) wait times has become a common practice in the United States. Proponents of this practice state that it is a powerful marketing strategy that can help steer patients to the ED. Opponents worry about the risk to the public health that arises from a patient with an emergent condition self-triaging to a further hospital, problems with inaccuracy and lack of standard definition of the reported time, and directing lower acuity patients to the higher cost ED setting instead to primary care. Three sample cases demonstrating the pitfalls of advertising ED wait times are discussed. Given the lack of rigorous evidence supporting the practice and potential adverse effects to the public health, caution about its use is advised. PMID:23599836

  20. After treatment ends: neutral time.

    PubMed

    Hurt, G J; McQuellon, R P; Barrett, R J

    1994-01-01

    For persons diagnosed with cancer, the remission period may be marked by increased anxiety and distress. While the medical team may view remission as an eagerly anticipated milestone, the decreased medical surveillance during this time can cause a heightened fear of recurrence for the patient. One author has called this period of remission "neutral time," a time characterized by uncertainty. The safety signal hypothesis, developed by Martin Seligman, may help to explain the anxiety experienced by some patients during the remission period. Because cancer is frequently a silent disease with no overt symptoms, patients in remission often have no safety signal to indicate that the disease will not return. A case study is presented and discussed in light of these two concepts. PMID:7697080

  1. Multichannel Spectrometer of Time Distribution

    NASA Astrophysics Data System (ADS)

    Akindinova, E. V.; Babenko, A. G.; Vakhtel, V. M.; Evseev, N. A.; Rabotkin, V. A.; Kharitonova, D. D.

    2015-06-01

    For research and control of characteristics of radiation fluxes, radioactive sources in particular, for example, in paper [1], a spectrometer and methods of data measurement and processing based on the multichannel counter of time intervals of accident events appearance (impulses of particle detector) MC-2A (SPC "ASPECT") were created. The spectrometer has four independent channels of registration of time intervals of impulses appearance and correspondent amplitude and spectrometric channels for control along the energy spectra of the operation stationarity of paths of each of the channels from the detector to the amplifier. The registration of alpha-radiation is carried out by the semiconductor detectors with energy resolution of 16-30 keV. Using a spectrometer there have been taken measurements of oscillations of alpha-radiation 239-Pu flux intensity with a subsequent autocorrelative statistical analysis of the time series of readings.

  2. Hydrodynamic analysis of time series

    NASA Astrophysics Data System (ADS)

    Suciu, N.; Vamos, C.; Vereecken, H.; Vanderborght, J.

    2003-04-01

    It was proved that balance equations for systems with corpuscular structure can be derived if a kinematic description by piece-wise analytic functions is available [1]. For example, the hydrodynamic equations for one-dimensional systems of inelastic particles, derived in [2], were used to prove the inconsistency of the Fourier law of heat with the microscopic structure of the system. The hydrodynamic description is also possible for single particle systems. In this case, averages of physical quantities associated with the particle, over a space-time window, generalizing the usual ``moving averages'' which are performed on time intervals only, were shown to be almost everywhere continuous space-time functions. Moreover, they obey balance partial differential equations (continuity equation for the 'concentration', Navier-Stokes equation, a. s. o.) [3]. Time series can be interpreted as trajectories in the space of the recorded parameter. Their hydrodynamic interpretation is expected to enable deterministic predictions, when closure relations can be obtained for the balance equations. For the time being, a first result is the estimation of the probability density for the occurrence of a given parameter value, by the normalized concentration field from the hydrodynamic description. The method is illustrated by hydrodynamic analysis of three types of time series: white noise, stock prices from financial markets and groundwater levels recorded at Krauthausen experimental field of Forschungszentrum Jülich (Germany). [1] C. Vamoş, A. Georgescu, N. Suciu, I. Turcu, Physica A 227, 81-92, 1996. [2] C. Vamoş, N. Suciu, A. Georgescu, Phys. Rev E 55, 5, 6277-6280, 1997. [3] C. Vamoş, N. Suciu, W. Blaj, Physica A, 287, 461-467, 2000.

  3. Time changes, so do people.

    PubMed

    Suzuki, Etsuji

    2012-08-01

    When one discusses the dynamic changes in human health over time, one innately conceptualizes time from the three different, but related perspectives--age, period, and cohort. To determine their separate contributions to health outcomes, age-period-cohort analyses have been used for the past 80 years. This commentary aims to provide some insight into this analytical method by distinguishing the concept of time in terms of composition and context. To demonstrate, the author uses hypothetical nested data structures of age-period-cohort analyses in the two types of individual-level data, i.e., repeated cross-sectional survey and longitudinal data on the same individuals. The conceptual distinctions between composition and context have profound implications of hypothetical interventions in age-period-cohort analyses. Age is a compositional variable, and a hypothetical intervention to change age is at the individual level. By contrast, both period and cohort are contexts, and thus two distinct types of hypothetical interventions can be envisaged to examine their contextual effects. On a related issue, the author also discusses manipulability of time. Although time is a significant context in biomedical science, it is not the only context. In this commentary, context is proposed to be classified into three fundamental dimensions--relational, spatial, and temporal. Inattention to the contextual triad leads to a biased and precarious knowledge base for public health action, and the continuing flow of performance over time is an intrinsic component of improving our understanding of multilevel causal inference in the new era of eco-epidemiology. PMID:22591827

  4. Real-time flutter analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1984-01-01

    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

  5. PRECISION TIME-DELAY CIRCUIT

    DOEpatents

    Creveling, R.

    1959-03-17

    A tine-delay circuit which produces a delay time in d. The circuit a capacitor, an te back resistance, connected serially with the anode of the diode going to ground. At the start of the time delay a negative stepfunction is applied to the series circuit and initiates a half-cycle transient oscillatory voltage terminated by a transient oscillatory voltage of substantially higher frequency. The output of the delay circuit is taken at the junction of the inductor and diode where a sudden voltage rise appears after the initiation of the higher frequency transient oscillations.

  6. The Broken Symmetry of Time

    SciTech Connect

    Kastner, Ruth E.

    2011-11-29

    This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.

  7. Driven discrete time quantum walks

    NASA Astrophysics Data System (ADS)

    Hamilton, Craig S.; Barkhofen, Sonja; Sansoni, Linda; Jex, Igor; Silberhorn, Christine

    2016-07-01

    We introduce the driven discrete time quantum walk (QW), where walkers are added during the walk instead of only at the beginning. This leads to interference in walker number and very different dynamics when compared to the original QW. These dynamics have two regimes, which we illustrate using the one-dimensional line. Then, we explore a search application which has certain advantages over current search protocols, namely that it does not require a complicated initial state nor a specific measurement time to observe the marked state. Finally, we describe a potential experimental implementation using existing technology.

  8. Physical, neural, and mental timing.

    PubMed

    van de Grind, Wim

    2002-06-01

    The conclusions drawn by Benjamin Libet from his work with colleagues on the timing of somatosensorial conscious experiences has met with a lot of praise and criticism. In this issue we find three examples of the latter. Here I attempt to place the divide between the two opponent camps in a broader perspective by analyzing the question of the relation between physical timing, neural timing, and experiential (mental) timing. The nervous system does a sophisticated job of recombining and recoding messages from the sensorial surfaces and if these processes are slighted in a theory, it might become necessary to postulate weird operations, including subjective back-referral. Neuroscientifically inspired theories are of necessity still based on guesses, extrapolations, and philosophically dubious manners of speech. They often assume some neural correlate of consciousness (NCC) as a part of the nervous system that transforms neural activity in reportable experiences. The majority of neuroscientists appear to assume that the NCC can compare and bind activity patterns only if they arrive simultaneously at the NCC. This leads to a search for synchrony or to theories in terms of the compensation of differences in neural delays (latencies). This is the main dimension of the Libet discussion. Examples from vision research, such as "temporal-binding-by-synchrony" and the "flash-lag" effect, are then used to illustrate these reasoning patterns in more detail. Alternatively one could assume symbolic representations of time and space (symbolic "tags") that are not coded in their own dimension (not time in time and space in space). Unless such tags are multiplexed with the quality message (tickle, color, or motion), one gets a binding problem for tags. One of the hidden aspects of the discussion between Libet and opponents appears to be the following. Is the NCC smarter than the rest of the nervous system, so that it can solve the problems of local sign (e.g., "where is the event

  9. Comment on ``Quantum tunneling time''

    NASA Astrophysics Data System (ADS)

    Hahne, G. E.

    2005-02-01

    In this Comment on the paper by Wanget al., Phys. Rev. A692004052108], it is pointed out that (i) a group-theoretical argument advanced in the first part of their derivation is both flawed and not needed in what follows, (ii) they then assert a formula that leads to a physically incorrect phase (as distinguished from group) delay time in the motion of a free particle, and (iii) their subsequent derivation contains a mathematical error, such that the outcome is a new formula for the tunneling time that avoids the second problem, but such that the result is unfounded and is therefore of unknown physical content.

  10. Time-division SQUID multiplexers

    NASA Astrophysics Data System (ADS)

    Irwin, K. D.; Vale, L. R.; Bergren, N. E.; Deiker, S.; Grossman, E. N.; Hilton, G. C.; Nam, S. W.; Reintsema, C. D.; Rudman, D. A.; Huber, M. E.

    2002-02-01

    SQUID multiplexers make it possible to build arrays of thousands of low-temperature bolometers and microcalorimeters based on superconducting transition-edge sensors with a manageable number of readout channels. We discuss the technical tradeoffs between proposed time-division multiplexer and frequency-division multiplexer schemes and motivate our choice of time division. Our first-generation SQUID multiplexer is now in use in an astronomical instrument. We describe our second-generation SQUID multiplexer, which is based on a new architecture that significantly reduces the dissipation of power at the first stage, allowing thousands of SQUIDs to be operated at the base temperature of a cryostat. .

  11. Lessons from Earth's Deep Time

    ERIC Educational Resources Information Center

    Soreghan, G. S.

    2005-01-01

    Earth is a repository of data on climatic changes from its deep-time history. Article discusses the collection and study of these data to predict future climatic changes, the need to create national study centers for the purpose, and the necessary cooperation between different branches of science in climatic research.

  12. Economic Time-Series Page.

    ERIC Educational Resources Information Center

    Bos, Theodore; Culver, Sarah E.

    2000-01-01

    Describes the Economagic Web site, a comprehensive site of free economic time-series data that can be used for research and instruction. Explains that it contains 100,000+ economic data series from sources such as the Federal Reserve Banking System, the Census Bureau, and the Department of Commerce. (CMK)

  13. Timing of the Medical Examination

    ERIC Educational Resources Information Center

    Christian, Cindy W.

    2011-01-01

    The medical examination of the sexually abused child may have evidentiary, medical, and therapeutic purposes, and the timing of the examination requires consideration of each of these objectives. In cases of acute sexual assault, emergent examinations may be needed to identify injury, collect forensic evidence, and provide infection and pregnancy…

  14. Infuse Creativity in No Time

    ERIC Educational Resources Information Center

    Hudson, Hannah

    2011-01-01

    While the four C's--critical thinking, creativity, collaboration, and communication--will naturally fit into a school's existing curriculum, changing the school culture to emphasize these skills takes time and planning. The good news is that school leaders can get started in just a few minutes. In this article, the author presents practical steps…

  15. Time dependent view factor methods

    SciTech Connect

    Kirkpatrick, R.C.

    1998-03-01

    View factors have been used for treating radiation transport between opaque surfaces bounding a transparent medium for several decades. However, in recent years they have been applied to problems involving intense bursts of radiation in enclosed volumes such as in the laser fusion hohlraums. In these problems, several aspects require treatment of time dependence.

  16. GOES satellite time code dissemination

    NASA Technical Reports Server (NTRS)

    Beehler, R. E.

    1983-01-01

    The GOES time code system, the performance achieved to date, and some potential improvements in the future are discussed. The disseminated time code is originated from a triply redundant set of atomic standards, time code generators and related equipment maintained by NBS at NOAA's Wallops Island, VA satellite control facility. It is relayed by two GOES satellites located at 75 W and 135 W longitude on a continuous basis to users within North and South America (with overlapping coverage) and well out into the Atlantic and Pacific ocean areas. Downlink frequencies are near 468 MHz. The signals from both satellites are monitored and controlled from the NBS labs at Boulder, CO with additional monitoring input from geographically separated receivers in Washington, D.C. and Hawaii. Performance experience with the received time codes for periods ranging from several years to one day is discussed. Results are also presented for simultaneous, common-view reception by co-located receivers and by receivers separated by several thousand kilometers.

  17. "Sharing Time" with Young Learners

    ERIC Educational Resources Information Center

    Yazigi, Rana; Seedhouse, Paul

    2005-01-01

    Although "Sharing Time" is a popular and widespread activity in English for Young Learners (L2) classrooms around the world, there have so far been no research studies of the interaction that is generated and its relationship to learning processes. The aims of this study were to find out how interaction is organized during "Sharing…

  18. Calorimeter Timing System at CDF

    SciTech Connect

    Goncharov, Max

    2006-10-27

    We report on the design and performance of the electromagnetic calorimeter timing readout system (EMTiming) for the Collider Detector at Fermilab (CDF). The system is used in searches for rare events with high-energy photons to verify that the photon is in time with the event collision, and to reject cosmic-ray and beam-halo backgrounds. The installation and commissioning of all 862 channels was completed in Fall 2004 as part of an upgrade to the Run II version of the detector. Using in-situ data, we measure the energy threshold for a time to be recorded to be 3.8{+-}0.3 GeV and 1.9{+-}0.1 GeV in the central (CEM) and plug (PEM) portions of the detector. Similarly, for the central and plug portions we measure a timing resolution of 600{+-}10 ps and 610{+-}10 ps for electrons above 10 GeV (6 GeV). Pathologies such as noise and non-Gaussian tails are virtually non-existent.

  19. High resolution time interval counter

    DOEpatents

    Condreva, Kenneth J.

    1994-01-01

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured.

  20. High resolution time interval counter

    DOEpatents

    Condreva, K.J.

    1994-07-26

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured. 3 figs.