Science.gov

Sample records for accelerator related backgrounds

  1. Uniform acceleration in general relativity

    NASA Astrophysics Data System (ADS)

    Friedman, Yaakov; Scarr, Tzvi

    2015-10-01

    We extend de la Fuente and Romero's (Gen Relativ Gravit 47:33, 2015) defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.

  2. STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING

    SciTech Connect

    Chernyshov, D. O.; Dogiel, V. A.; Ko, C. M.

    2012-11-10

    The origin of hard X-ray (HXR) excess emission from clusters of galaxies is still an enigma, whose nature is debated. One of the possible mechanisms to produce this emission is the bremsstrahlung model. However, previous analytical and numerical calculations showed that in this case the intracluster plasma had to be overheated very fast because suprathermal electrons emitting the HXR excess lose their energy mainly by Coulomb losses, i.e., they heat the background plasma. It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by the background plasma. In other words, the Fermi acceleration is ineffective for particle acceleration. We revisited this problem and found that at some parameter of acceleration the rate of plasma heating is rather low and the acceleration tails of nonthermal particles can be generated and exist for a long time while the plasma temperature is almost constant. We showed also that for some regime of acceleration the plasma cools down instead of being heated up, even though external sources (in the form of external acceleration) supply energy to the system. The reason is that the acceleration withdraws effectively high-energy particles from the thermal pool (analog of Maxwell demon).

  3. Cosmic acceleration without dark energy: background tests and thermodynamic analysis

    SciTech Connect

    Lima, J.A.S.; Graef, L.L.; Pavón, D.; Basilakos, Spyros E-mail: leilagraef@usp.br E-mail: svasil@academyofathens.gr

    2014-10-01

    A cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation pressure associated with the cold dark matter component. The model can be interpreted as an attempt to reduce the so-called cosmic sector (dark matter plus dark energy) and relate the two cosmic accelerating phases (early and late time de Sitter expansions). A detailed thermodynamic analysis including possible quantum corrections is also carried out. For a very wide range of the free parameters, it is found that the model presents the expected behavior of an ordinary macroscopic system in the sense that it approaches thermodynamic equilibrium in the long run (i.e., as it nears the second de Sitter phase). Moreover, an upper bound is found for the Gibbons–Hawking temperature of the primordial de Sitter phase. Finally, when confronted with the recent observational data, the current 'quasi'-de Sitter era, as predicted by the model, is seen to pass very comfortably the cosmic background tests.

  4. Cosmic acceleration without dark energy: background tests and thermodynamic analysis

    NASA Astrophysics Data System (ADS)

    Lima, J. A. S.; Graef, L. L.; Pavón, D.; Basilakos, Spyros

    2014-10-01

    A cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation pressure associated with the cold dark matter component. The model can be interpreted as an attempt to reduce the so-called cosmic sector (dark matter plus dark energy) and relate the two cosmic accelerating phases (early and late time de Sitter expansions). A detailed thermodynamic analysis including possible quantum corrections is also carried out. For a very wide range of the free parameters, it is found that the model presents the expected behavior of an ordinary macroscopic system in the sense that it approaches thermodynamic equilibrium in the long run (i.e., as it nears the second de Sitter phase). Moreover, an upper bound is found for the Gibbons-Hawking temperature of the primordial de Sitter phase. Finally, when confronted with the recent observational data, the current `quasi'-de Sitter era, as predicted by the model, is seen to pass very comfortably the cosmic background tests.

  5. Distribution of the background gas in the MITICA accelerator

    NASA Astrophysics Data System (ADS)

    Sartori, E.; Dal Bello, S.; Serianni, G.; Sonato, P.

    2013-02-01

    MITICA is the ITER neutral beam test facility to be built in Padova for the generation of a 40A D- ion beam with a 16×5×16 array of 1280 beamlets accelerated to 1MV. The background gas pressure distribution and the particle flows inside MITICA accelerator are critical aspects for stripping losses, generation of secondary particles and beam non-uniformities. To keep the stripping losses in the extraction and acceleration stages reasonably low, the source pressure should be 0.3 Pa or less. The gas flow in MITICA accelerator is being studied using a 3D Finite Element code, named Avocado. The gas-wall interaction model is based on the cosine law, and the whole vacuum system geometry is represented by a view factor matrix based on surface discretization and gas property definitions. Pressure distribution and mutual fluxes are then solved linearly. In this paper the result of a numerical simulation is presented, showing the steady-state pressure distribution inside the accelerator when gas enters the system at room temperature. The accelerator model is limited to a horizontal slice 400 mm high (1/4 of the accelerator height). The pressure profile at solid walls and through the beamlet axis is obtained, allowing the evaluation and the discussion of the background gas distribution and nonuniformity. The particle flux at the inlet and outlet boundaries (namely the grounded grid apertures and the lateral conductances respectively) will be discussed.

  6. Simulation of PEP-II Accelerator Backgrounds Using TURTLE

    SciTech Connect

    Barlow, R.J.; Fieguth, T.; Kozanecki, W.; Majewski, S.A.; Roudeau, P.; Stocchi, A.; /Orsay, LAL

    2006-02-15

    We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full program of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

  7. Intergalactic shock acceleration and the cosmic gamma-ray background

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco

    2002-11-01

    We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-ray ions and electrons accelerated at intergalactic shocks associated with cosmological structure formation. We show that the kinetic energy of accretion flows in the low-redshift intergalactic medium is thermalized primarily through moderately strong shocks, which allow for an efficient conversion of shock ram pressure into cosmic-ray pressure. Cosmic rays accelerated at these shocks produce a diffuse gamma-ray flux which is dominated by inverse Compton emission from electrons scattering off cosmic microwave background photons. Decay of neutral π mesons generated in p-p inelastic collisions of the ionic cosmic-ray component with the thermal gas contribute about 30 per cent of the computed emission. Based on experimental upper limits on the photon flux above 100 MeV from nearby clusters we constrain the efficiency of conversion of shock ram pressure into relativistic CR electrons to <~1 per cent. Thus, we find that cosmic rays of cosmological origin can generate an overall significant fraction of order 20 per cent and no more than 30 per cent of the measured gamma-ray background.

  8. Testing general relativity on accelerators

    NASA Astrophysics Data System (ADS)

    Kalaydzhyan, Tigran

    2015-11-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable - maximal energy of the scattered photons - would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.

  9. Low Frequency Electromagnetic Background Radiation From Electron Acceleration Above Thunderclouds

    NASA Astrophysics Data System (ADS)

    Fullekrug, Martin; Mezentsev, Andrew; Soula, Serge; van der Velde, Oscar; Farges, Thomas

    2013-04-01

    It was recently proposed that the acceleration of electrons during the growth and branching of streamers above thunderclouds initiated by intense lightning discharges could result in detectable low frequency electromagnetic radiation from several tens of kHz up to several hundreds of kHz (Qin et al., GRL, 2012). The intensity of the predicted radiation scales with the streamer density which is particularly large during spectacular sprite occurrences such as jellyfish sprites and/or dancing sprites. Dancing sprites are up to one second long sequences of consecutive sprites or sprite groups which are typically separated by some hundreds of milliseconds and which tend to follow the spatial development of large scale intracloud lightning discharges. A particularly spectacular series of 10 dancing sprite events over a Mediterranean mesoscale convective system was recorded with a low light video camera in south-eastern France during the early morning hours of August 31, 2012. Each dancing sprite event was composed of ~3-4 consecutive sprites or groups of sprites. All of these sprite occurrences were associated with a sudden enhancement ~2 uV/m/Hz-1/2 of the low frequency electromagnetic background radiation as measured with a radio receiver in south-west England. It is estimated that ~1000 streamers at a height of ~40 km are necessary to epxlain the observed electric field strengths. These sudden enhancements are superimposed on a more continuous low frequency electromagnetic background radiation which accompanies each dancing sprite event. It is speculated that this low frequency 'radio glow' results from filamentary streamers near the cloud top as a result of the large scale electrostatic charging of the thundercloud and that it may be used as an indicator for sprite occurrences in future studies.

  10. Multi-wavelength emission from the Fermi bubbles. I. Stochastic acceleration from background plasma

    SciTech Connect

    Cheng, K. S.; Chernyshov, D. O.; Dogiel, V. A.; Ko, C. M.

    2014-07-20

    We analyze processes of electron acceleration in the Fermi bubbles in order to define parameters and restrictions of the models, which are suggested for the origin of these giant radio and gamma-ray structures. In the case of the leptonic origin of the nonthermal radiation from the bubbles, these electrons should be produced somehow in situ because of the relatively short lifetime of high-energy electrons, which lose their energy by synchrotron and inverse-Compton processes. It has been suggested that electrons in bubbles may be accelerated by shocks produced by tidal disruption of stars accreting onto the central black hole or a process of re-acceleration of electrons ejected by supernova remnants. These processes will be investigated in subsequent papers. In this paper, we focus on in situ stochastic (Fermi) acceleration by a hydromagnetic/supersonic turbulence, in which electrons can be directly accelerated from the background plasma. We showed that the acceleration from the background plasma is able to explain the observed fluxes of radio and gamma-ray emission from the bubbles, but the range of permitted parameters of the model is strongly restricted.

  11. FEL-accelerator related diagnostics

    SciTech Connect

    Kevin Jordan; David Douglas; Stephen V. Benson; Pavel Evtuschenko

    2007-08-02

    Free Electron Lasers (FEL) present a unique set of beam parameters to the diagnostics suite. The FEL requires characterization of the full six dimensional phase space of the electron beam at the wiggler and accurate alignment of the electron beam to the optical mode of the laser. In addition to the FEL requirements on the diagnostics suite, the Jefferson Lab FEL is operated as an Energy Recovered Linac (ERL) which imposes additional requirements on the diagnostics. The ERL aspect of the Jefferson Lab FEL requires that diagnostics operate over a unique dynamic range and operate with simultaneous transport of the accelerated and energy recovered beams. This talk will present how these challenges are addressed at the Jefferson Lab FEL.

  12. Cosmic microwave background anisotropy from nonlinear structures in accelerating universes

    SciTech Connect

    Sakai, Nobuyuki; Inoue, Kaiki Taro

    2008-09-15

    We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by Lemaitre-Tolman-Bondi spacetimes, we numerically solve the null geodesic equations with the Einstein equations. We find that a nonlinear void redshifts the CMB photons that pass through it regardless of the distance to it. In contrast, a nonlinear lump blueshifts (or redshifts) the CMB photons if it is located near (or sufficiently far from) us. The present analysis comprehensively covers previous works based on a thin-shell approximation and a linear/second-order perturbation method and the effects of shell thickness and full nonlinearity. Our results indicate that, if quasilinear and large (> or approx.100 Mpc) voids/lumps would exist, they could be observed as cold or hot spots with temperature variance > or approx. 10{sup -5} K in the CMB sky.

  13. Blazar Gamma-Rays, Shock Acceleration, and the Extragalactic Background Light

    NASA Technical Reports Server (NTRS)

    Stecker, Floyd W.; Baring, Matthew G.; Summerlin, Errol J.

    2007-01-01

    The observed spectra of blazars, their intrinsic emission, and the underlying populations of radiating particles are intimately related. The use of these sources as probes of the extragalactic infrared background, a prospect propelled by recent advances in TeV-band telescopes, soon to be augmented by observations by NASA's upcoming Gamma-Ray Large Area Space Telescope (GLAST), has been a topic of great recent interest. Here, it is demonstrated that if particles in blazar jets are accelerated at relativistic shocks, then GAMMA-ray spectra with indices less than 1.5 can be produced. This, in turn, loosens the upper limits on the near infrared extragalactic background radiation previously proposed. We also show evidence hinting that TeV blazars with flatter spectra have higher intrinsic TeV GAMMA-ray luminosities and we indicate that there may be a correlation of flatness and luminosity with redshift.

  14. Biosensors Related LLT: Physiopathology, Background and Rationale

    NASA Astrophysics Data System (ADS)

    Palmieri, Beniamino; Capone, Stefania

    2011-08-01

    The Authors describe a new biosensor-related approach to LLT delivery, tailored to homogeneously integrate the external energy to the maximum patient compliance and receptivity; this project is based on the work hypothesis, by a pilot clinical trial and experimental animals (liver crush injury in the rat) confirmed that the diodes number, frequency, intensity, and pulses when synchronized with the vital parameters induce maximal physiological response in terms of regeneration and recovery.

  15. Background Knowledge in Learning-Based Relation Extraction

    ERIC Educational Resources Information Center

    Do, Quang Xuan

    2012-01-01

    In this thesis, we study the importance of background knowledge in relation extraction systems. We not only demonstrate the benefits of leveraging background knowledge to improve the systems' performance but also propose a principled framework that allows one to effectively incorporate knowledge into statistical machine learning models for…

  16. Background seismicity in Boso Peninsula, Japan: Long-term acceleration, and relationship with slow slip events

    NASA Astrophysics Data System (ADS)

    Reverso, T.; Marsan, D.; Helmstetter, A.; Enescu, B.

    2016-06-01

    Slow slip events (SSEs) in subduction zones can trigger earthquake swarms, especially at shallow depth. The monitoring of seismicity rates has therefore the potential to help detect and characterize SSEs, and transient changes in coupling. However, the relationship between seismicity rate and slow slip rate during a SSE is unknown and made complicated by aftershock triggering within the swarm. Here we propose to complement geodetic methods with an objective measure of the seismicity rate that is directly associated with changes in slip rate. We show that this measure, applied to known occurrences of SSEs in the Boso area, Japan, yields an estimate, albeit indirect, of their seismic moment, hence their slip rate. We finally prove that the background rate in Boso has been accelerating since 1990; this explains previous observations of the shortening of the recurrence time between SSEs in Boso, that clearly predate the 2011 Mw9.0 Tohoku-Oki earthquake.

  17. FUELING LOBES OF RADIO GALAXIES: STATISTICAL PARTICLE ACCELERATION AND THE EXTRAGALACTIC {gamma}-RAY BACKGROUND

    SciTech Connect

    Massaro, F.; Ajello, M.

    2011-03-01

    The recent discovery of the {gamma}-ray emission from the lobes of the closest radio galaxy Centaurus A by Fermi implies the presence of high-energy electrons at least up to {gamma} {approx} 10{sup 5}-10{sup 6}. These high-energy electrons are required to interpret the observed {gamma}-ray radiation in terms of inverse Compton emission off the cosmic microwave background (IC/CMB), the widely accepted scenario to describe the X-ray emission of radio galaxy lobes. In this Letter, we consider the giant radio lobes of FR II radio galaxies showing that it is possible to maintain electrons at energies {gamma} {approx} 10{sup 5}-10{sup 6}, assuming an acceleration scenario (driven by turbulent magnetic fields) that compensates radiative losses. In addition, we consider the contribution to the diffuse extragalactic {gamma}-ray background due to the IC/CMB emission of FR IIs' lobes, showing its relevance in the keV to MeV energy range.

  18. Analysis of accelerated motion in the theory of relativity

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    Conventional treatments of accelerated motion in the theory of relativity have led to certain difficulties of interpretation. Certain reversals in the apparent gravitational field of an accelerated body may be avoided by simpler analysis based on the use of restricted conformal transformations. In the conformal theory the velocity of light remains constant even for experimenters in accelerated motion. The problem considered is that of rectilinear motion with a variable velocity. The motion takes place along the x or x' axis of two coordinate systems.

  19. Radon-related backgrounds in the LUX dark matter search

    SciTech Connect

    Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; de Viveiros, L.; Dobi, A.; Dobson, J.; Druszkiewicz, E.; Edwards, B.; Faham, C. H.; Fiorucci, S.; Flores, C.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G.D.; Hall, C.; Hertel, S. A.; Horn, M.; Huang, D. Q.; Ihm, M.; Jacobsen, R. G.; Kazkaz, K.; Knoche, R.; Larsen, N. A.; Lee, C.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Mannino, R.; McKinsey, D. N.; Mei, D. -M.; Mock, J.; Moongweluwan, M.; Morad, J.; Murphy, A. St.J.; Nehrkorn, C.; Nelson, H.; Neves, F.; Ott, R. A.; Pangilinan, M.; Parker, P. D.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Shutt, T.; Silva, C.; Solovov, V. N.; Sorensen, P.; O'Sullivan, K.; Sumner, T. J.; Szydagis, M.; Taylor, D.; Tennyson, B.; Tiedt, D. R.; Tripathi, M.; Uvarov, S.; Verbus, J. R.; Walsh, N.; Webb, R.; White, J. T.; Witherell, M. S.; Wolfs, F. L.H.; Woods, M.; Zhang, C.

    2015-01-01

    The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.

  20. Radon-related backgrounds in the LUX dark matter search

    DOE PAGESBeta

    Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; et al

    2015-01-01

    The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

  1. Relating Time-Dependent Acceleration and Height Using an Elevator

    ERIC Educational Resources Information Center

    Kinser, Jason M.

    2015-01-01

    A simple experiment in relating a time-dependent linear acceleration function to height is explored through the use of a smartphone and an elevator. Given acceleration as a function of time, a(t), the velocity function and position functions are determined through integration as in v(t)=? a(t) dt (1) and x(t)=? v(t) dt. Mobile devices such as…

  2. Low-rank and Sparse Matrix Decomposition for Accelerated Dynamic MRI with Separation of Background and Dynamic Components

    PubMed Central

    Otazo, Ricardo; Candès, Emmanuel; Sodickson, Daniel K.

    2014-01-01

    Purpose To apply the low-rank plus sparse (L+S) matrix decomposition model to reconstruct undersampled dynamic MRI as a superposition of background and dynamic components in various problems of clinical interest. Theory and Methods The L+S model is natural to represent dynamic MRI data. Incoherence between k−t space (acquisition) and the singular vectors of L and the sparse domain of S is required to reconstruct undersampled data. Incoherence between L and S is required for robust separation of background and dynamic components. Multicoil L+S reconstruction is formulated using a convex optimization approach, where the nuclear-norm is used to enforce low-rank in L and the l1-norm to enforce sparsity in S. Feasibility of the L+S reconstruction was tested in several dynamic MRI experiments with true acceleration including cardiac perfusion, cardiac cine, time-resolved angiography, abdominal and breast perfusion using Cartesian and radial sampling. Results The L+S model increased compressibility of dynamic MRI data and thus enabled high acceleration factors. The inherent background separation improved background suppression performance compared to conventional data subtraction, which is sensitive to motion. Conclusion The high acceleration and background separation enabled by L+S promises to enhance spatial and temporal resolution and to enable background suppression without the need of subtraction or modeling. PMID:24760724

  3. Relating Time-Dependent Acceleration and Height Using an Elevator

    NASA Astrophysics Data System (ADS)

    Kinser, Jason M.

    2015-04-01

    A simple experiment in relating a time-dependent linear acceleration function to height is explored through the use of a smartphone and an elevator. Given acceleration as a function of time1, a(t), the velocity function and position functions are determined through integration as in v (t ) =∫ a (t ) d t (1) and x (t ) =∫ v (t ) dt. Mobile devices such as smartphones or tablets have accelerometers that capture slowly evolving acceleration with respect to time and can deliver those measurements as a CSV file. A recent example measured the oscillations of the elevator as it starts its motion.2 In the application presented here the mobile device is used to estimate the height of the elevator ride. By estimating the functional form of the acceleration of an elevator ride, it is possible to estimate the height of the ride through Eqs. (1) and (2).

  4. Nonexistence of the self-accelerating dipole and related questions

    NASA Astrophysics Data System (ADS)

    Steane, Andrew M.

    2014-06-01

    We calculate the self-force of a constantly accelerating electric dipole, showing, in particular, that classical electromagnetism does not predict that an electric dipole could self-accelerate, nor could it levitate in a gravitational field. We also resolve a paradox concerning the inertial mass of a longitudinally accelerating dipole, showing that the combined system of dipole plus field can be assigned a well-defined energy-momentum four-vector, so that the principle of relativity is satisfied. We then present some general features of electromagnetic phenomena in a reference frame described by the Rindler metric, showing in particular that an observer fixed in a gravitational field described everywhere by the Rindler metric will find any charged object supported in the gravitational field to possess an electromagnetic self-force equal to that observed by an inertial observer relative to which the body undergoes rigid hyperbolic motion. It follows that the principle of equivalence is satisfied by these systems.

  5. Detector-related backgrounds in the Karlsruhe Tritium Neutrino Experiment

    NASA Astrophysics Data System (ADS)

    Leber, Michelle; Katrin Collaboration

    2011-12-01

    The Karlsruhe Tritium Neutrino Experiment, or KATRIN, is a next generation tritium beta decay experiment to directly measure neutrino mass with an expected sensitivity of 0.2 eV [KATRIN Design Report 2004 see http://www-ik.fzk.de/~katrin/]. Neutrino mass does not fit into the Standard Model, and determining this mass may set the scale of new physics. To achieve this level of sensitivity, backgrounds in the experiment must be minimized. A complete Geant4 [Agostinelli S et al. 2003 Nuclear Instr. Methods A 506 250-303 Allison J et al. 2006 IEEE Transactions on Nuclear Science53 No. 1 270-8] simulation of KATRIN's focal plane detector and surrounding region is being developed. These simulations will help guide the design and selection of shielding and detector construction materials to reduce backgrounds from cosmic rays and natural radioactivity.

  6. Injection Related Background due to the Transverse Feedback

    SciTech Connect

    Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.; /SLAC

    2008-03-18

    The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part.

  7. Microscopic background of the Onsager-Casimir reciprocity relations

    SciTech Connect

    Titulaer, U.M.

    1988-10-01

    It has been known for some time that small deviations from the Onsager-Casimir symmetry relations are introduced when one passes from a given description of a system to a less detailed one by adiabatic elimination of fast variables. Exact validity is preserved, however, for a slightly modified form of these relations. In this paper the question is considered whether this modified Onsager symmetry is also preserved by the transition from a microscopic to a mesoscopic description, the step that introduces manifest irreversibility into the equations of motion. This question is examined in detail for a system of a few heavy oscillators coupled to a bath, a model discussed in a recent paper by van Kampen. The modified Onsager symmetry survives the transition to an irreversible description via the dense spectrum approximation. This is shown explicitly by inspection of the results obtained by van Kampen; some arguments favoring a more general validity are also briefly discussed.

  8. Accelerators for charged particle therapy: PAMELA and related issues

    NASA Astrophysics Data System (ADS)

    Peach, Ken

    2014-05-01

    Cancer is a dreadful disease that will affect one in three people at some point in their life; radiotherapy is used in more than half of all cancer treatment, and contributes about 40% to the successful treatment of cancer. Charged Particle Therapy uses protons and other light ions to deliver the lethal dose to the tumor while being relatively sparing of healthy tissue and, because of the finite range of the particles, is able to avoid giving any dose to vital organs. While there are adequate technologies currently available to deliver the required energies and fluxes, the two main technologies (cyclotrons and synchrotrons) have limitations. PAMELA (the Particle Accelerator for MEdicaLApplications) uses the newly-developed non-scaling Fixed Field Alternating Gradient accelerator concepts to deliver therapeutically relevant beams. The status of the development of the PAMELA conceptual design is discussed.

  9. Low-rank + sparse (L+S) reconstruction for accelerated dynamic MRI with seperation of background and dynamic components

    NASA Astrophysics Data System (ADS)

    Otazo, Ricardo; Sodickson, Daniel K.; Candès, Emmanuel J.

    2013-09-01

    L+S matrix decomposition finds the low-rank (L) and sparse (S) components of a matrix M by solving the following convex optimization problem: min‖L‖*L+S matrix decomposition finds the low-rank (L) and sparse (S) components of a matrix M by solving the following convex optimization problem: ‖L ‖* + λ‖S‖1, subject to M=L+S, where ‖L‖* is the nuclear-norm or sum of singular values of L and ‖S‖1 is the 11-norm| or sum of absolute values of S. This work presents the application of the L+S decomposition to reconstruct incoherently undersampled dynamic MRI data as a superposition of a slowly or coherently changing background and sparse innovations. Feasibility of the method was tested in several accelerated dynamic MRI experiments including cardiac perfusion, time-resolved peripheral angiography and liver perfusion using Cartesian and radial sampling. The high acceleration and background separation enabled by L+S reconstruction promises to enhance spatial and temporal resolution and to enable background suppression without the need of subtraction or modeling.

  10. Kinematically Accelerated Repulsions Due to Relative Motion between Mass Particles in an Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Savickas, David

    2016-03-01

    An accelerated expansion of the universe, due only to relative particle motion, is described here in the form of a particular model that illustrates its physical cause. A simplified three particle universe is considered here by defining coordinate positions for effective mass-points because their size is extremely small compared to the distances between them. The three particles initially form a static isosceles triangular configuration. The third particle at the triangle's apex could only then determine its position relative to the triangle by measuring the apex angle subtended by the base particles. If the two base particles then exert for an instant a force between only themselves, they will move away from each other while the third particle could physically maintain its position relative to the universe only by referring to these other two existing particles. It would then be required that the apex particle would accelerate outwards and away from the base particles in order to regain the smaller size of the original apex angle and subsequently generate a Hubble expansion for the particles.

  11. Efficient acceleration of dense plasma bunches for fusion-related applications in the LICPA accelerator

    NASA Astrophysics Data System (ADS)

    Badziak, Jan; Jabłoński, Slawomir

    2014-05-01

    The results of particle-in-cell simulations of acceleration of carbon ions and a heavy (0.5 μg) gold micro-projectile in the laser-induced cavity pressure acceleration (LICPA) scheme at the conditions relevant to fast ignition of deuterium-tritium (DT) fusion are presented. It is shown that the LICPA accelerator employing a picosecond 100 kJ laser driver can produce quasi-monoenergetic carbon ion beams of parameters significantly higher than those achieved in the conventional radiation pressure acceleration (RPA) scheme and the beam parameters meet the ion fast ignition requirements fairly well. The LICPA accelerator can also efficiently accelerate the heavy micro-projectile to high velocities (> 5 × 108 cm s-1) required for the impact ignition of DT fusion and the acceleration efficiency for LICPA is almost an order of magnitude higher than that for RPA.

  12. Acceleration-Deceleration Sport-Related Concussion: The Gravity of It All

    PubMed Central

    Freeman, Jason R.; Broshek, Donna K.; Varney, Robert N.

    2001-01-01

    Objective: To discuss a newtonian physics model for understanding and calculating acceleration-deceleration forces found in sport-related cerebral concussions and to describe potential applications of this formula, including (1) an attempt to measure the forces applied to the brain during acceleration-deceleration injuries, (2) a method of accruing objective data regarding these forces, and (3) use of these data to predict functional outcome, such as neurocognitive status, recovery curves, and return to play. Background: Mild concussion in sports has gained considerable attention in the last decade. Athletic trainers and team physicians have attempted to limit negative outcomes by gaining a better understanding of the mechanisms and severity of mild head injuries and by developing meaningful return-to-play criteria. Mild head injury in sports has become an even greater area of focus and concern, given the negative neurobehavioral outcomes experienced by several recent high-profile professional athletes who sustained repeated concussions. Applying the principles of physics to characterize injury types, injury severity, and outcomes may further our development of better concussion management techniques and prevention strategies. Description: We describe the search for models to explain neuronal injury secondary to concussion and provide an exploratory method for quantifying acceleration-deceleration forces and their relationship to severity of mild head injury. Implications for injury prevention and reduction of morbidity are also considered. PMID:12937493

  13. On the angle between relative velocity and relative acceleration between two fluid particles in turbulence

    NASA Astrophysics Data System (ADS)

    Xu, Haitao; Pumir, Alain; Bodenschatz, Eberhard

    2012-11-01

    In turbulence study, it is often desirable to know if locally the flow is strain-dominated or vorticity-dominated. This information not only is related to the local flow topology, it also reveals where small particles with weak inertia accumulate. However, to determine whether strain or vorticity is dominating requires access to the velocity gradient tensor, which is difficult to measure experimentally. By using results from direct numerical simulation of fully developed turbulence we show that the angle between the relative velocity and the relative acceleration between two fluid particles can be used as an indicator of strain-dominated versus vorticity-dominated flow structure. This new indicator has the advantage that it is much more easily accessible experimentally than measuring the velocity gradients. We also present further turbulence statistics from both DNS and experiments conditioned on the angle between relative velocity and relative acceleration and compare them with those conditioned on strain and vorticity. We thank financial supports from MPG, DFG, IDRIS, and ANR.

  14. Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

    2014-01-01

    The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thruster's anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization and acceleration zones upstream shifting as a function of increased background pressure.

  15. The X-ray log N-log S relation. [background radiation in extragalactic media

    NASA Technical Reports Server (NTRS)

    Boldt, Elihu

    1989-01-01

    Results from various surveys are reviewed as regards X-ray source counts at high galactic latitudes and the luminosity functions determined for extragalactic sources. Constraints on the associated log N-log S relation provided by the extragalactic X-ray background are emphasized in terms of its spatial fluctuations and spectrum as well as absolute flux level. The large number of sources required for this background suggests that there is not a sharp boundary in the redshift distribution of visible matter.

  16. Spatial Relations between Force and Acceleration in Relativistic Mechanics.

    ERIC Educational Resources Information Center

    Redding, J. L.

    1982-01-01

    The lack of parallelism between the force and acceleration vectors has several apparently paradoxical consequences that have been recently examined. This article uses a different and more general mode of analysis than previous authors to derive quite general, rather than particular, results. (Author/SK)

  17. The impact of musicianship on the cortical mechanisms related to separating speech from background noise.

    PubMed

    Zendel, Benjamin Rich; Tremblay, Charles-David; Belleville, Sylvie; Peretz, Isabelle

    2015-05-01

    Musicians have enhanced auditory processing abilities. In some studies, these abilities are paralleled by an improved understanding of speech in noisy environments, partially due to more robust encoding of speech signals in noise at the level of the brainstem. Little is known about the impact of musicianship on attention-dependent cortical activity related to lexical access during a speech-in-noise task. To address this issue, we presented musicians and nonmusicians with single words mixed with three levels of background noise, across two conditions, while monitoring electrical brain activity. In the active condition, listeners repeated the words aloud, and in the passive condition, they ignored the words and watched a silent film. When background noise was most intense, musicians repeated more words correctly compared with nonmusicians. Auditory evoked responses were attenuated and delayed with the addition of background noise. In musicians, P1 amplitude was marginally enhanced during active listening and was related to task performance in the most difficult listening condition. By comparing ERPs from the active and passive conditions, we isolated an N400 related to lexical access. The amplitude of the N400 was not influenced by the level of background noise in musicians, whereas N400 amplitude increased with the level of background noise in nonmusicians. In nonmusicians, the increase in N400 amplitude was related to a reduction in task performance. In musicians only, there was a rightward shift of the sources contributing to the N400 as the level of background noise increased. This pattern of results supports the hypothesis that encoding of speech in noise is more robust in musicians and suggests that this facilitates lexical access. Moreover, the shift in sources suggests that musicians, to a greater extent than nonmusicians, may increasingly rely on acoustic cues to understand speech in noise. PMID:25390195

  18. The Impacts of Language Background and Language-Related Disorders in Auditory Processing Assessment

    ERIC Educational Resources Information Center

    Loo, Jenny Hooi Yin; Bamiou, Doris-Eva; Rosen, Stuart

    2013-01-01

    Purpose: To examine the impact of language background and language-related disorders (LRDs--dyslexia and/or language impairment) on performance in English speech and nonspeech tests of auditory processing (AP) commonly used in the clinic. Method: A clinical database concerning 133 multilingual children (mostly with English as an additional…

  19. Language-Related Values, Reading Amount, and Reading Comprehension in Students with Migration Backgrounds

    ERIC Educational Resources Information Center

    El-Khechen, Wahiba; Ferdinand, Hanna D.; Steinmayr, Ricarda; McElvany, Nele

    2016-01-01

    Background: Although various studies on general language performance have investigated determinants of students' reading comprehension (e.g., reading amount), they have paid insufficient attention to how students perceive parental values influence their language-related values and behaviour--and, as a consequence, their performance. This is…

  20. Role of Family Background, Student Behaviors, and School-Related Beliefs in Predicting High School Dropout

    ERIC Educational Resources Information Center

    Parr, Alyssa K.; Bonitz, Verena S.

    2015-01-01

    The authors' purpose was to test a parsimonious model derived from social cognitive career theory (R. W. Lent, S. D. Brown, & G. Hackett, 1994) and expectancy value theory (J. S. Eccles & A. Wigfield, 2002) that integrates groups of variables (demographic background, student behaviors, and school-related beliefs) with the goal of…

  1. Exploring How ESL Teachers Relate Their Ethnic and Social Backgrounds to Practice

    ERIC Educational Resources Information Center

    Ajayi, Lasisi

    2011-01-01

    This study is an exploration of how English as a second language (ESL) teachers relate their ethnic and social backgrounds to instructional practices. Fifty-seven ESL teachers from inner-city junior high schools of Los Angeles responded to a questionnaire, interviews and provided self-written perspectives on how their personal histories mediated…

  2. Helium Background in the D0 Detector Related to the Photomultiplier Tubes

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-04-09

    Helium is present in the earth's atmosphere at about 5 parts per million. (ref. Technology of liquid helium, NBS monograph 111). The D-Zero detector uses helium for the cryogenic cooling of its superconducting magnet and visible light photon counter (VLPC) electronics chips. In addition, the tevatron accelerator has superconducting magnets that use helium Due to the possibility of leaks or releases of helium from these helium lines and components, the background helium level in the collision hall may exceed the natural level of 5 ppm. This engineering note will quantify the probability and level of helium background in the D-Zero detector. The photomultiplier tubes used in the D-Zero detector are sensitive to an elevated helium atmosphere. This is due to the permeation rate of helium gas through the glass tube, into the vacuum space inside. It is very important for the helium atmosphere surrounding the photomultiplier tubes is known and controlled. If the level of helium in the vacuum tube reaches a level above 5 ppm, then the photomuliplier tube may no longer work as designed. The process is an irreversible one.

  3. Application of the National Ignition Facility distinguishable-from-background program to accelerator facilities at Lawrence Livermore National Laboratory.

    PubMed

    Packard, Eric D; Mac Kenzie, Carolyn

    2013-06-01

    Lawrence Livermore National Laboratory must control potentially activated materials and equipment in accordance with U.S. Department of Energy (DOE) Order 458.1, Radiation Protection of the Public and the Environment, which requires DOE approval of the process used to release volumetrically contaminated personal property and establishes a dose constraint of 10 µSv y(-1) (1 mrem y(-1)) for clearance of such property. The National Ignition Facility at Lawrence Livermore National Laboratory developed a technical basis document and protocol for determining the radiological status of property that is potentially activated from exposure to neutron radiation produced via fusion of tritium and deuterium. The technical basis included assessment of the neutron energy, the type of materials potentially exposed and the likely activation products, and the sensitivity of radiation detectors used to survey the property. This paper evaluates the National Ignition Facility technical basis document for applicability to the release of property from Lawrence Livermore National Laboratory's various accelerator facilities considering the different types of particles accelerated, radiations produced, and resultant activation products. Extensive process knowledge regarding the accelerators' operations, accompanied by years of routine surveys, provides an excellent characterization of these facilities. Activation studies conducted at the Stanford Linear Accelerator and the High Energy Accelerator Research Organization in Japan corroborate that the long-lived radionuclides produced at accelerator facilities are of the same variety produced at the National Ignition Facility. Consequently, Lawrence Livermore National Laboratory concludes that the release protocol developed for the National Ignition Facility can be used appropriately at all its accelerator facilities. PMID:23629069

  4. Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

    2014-01-01

    The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thrusters anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization.

  5. Urban enhancement of PM10 bioaerosol tracers relative to background locations in the Midwestern United States

    NASA Astrophysics Data System (ADS)

    Rathnayake, Chathurika M.; Metwali, Nervana; Baker, Zach; Jayarathne, Thilina; Kostle, Pamela A.; Thorne, Peter S.; O'Shaughnessy, Patrick T.; Stone, Elizabeth A.

    2016-05-01

    Bioaerosols are well-known immune-active particles that exacerbate respiratory diseases. Human exposures to bioaerosols and their resultant health impacts depend on their ambient concentrations, seasonal and spatial variation, and copollutants, which are not yet widely characterized. In this study, chemical and biological tracers of bioaerosols were quantified in respirable particulate matter (PM10) collected at three urban and three background sites in the Midwestern United States across four seasons in 2012. Endotoxins from Gram-negative bacteria (and a few Gram-positive bacteria), water-soluble proteins, and tracers for fungal spores (fungal glucans, arabitol, and mannitol) were ubiquitous and showed significant seasonal variation and dependence on temperature. Fungal spores were elevated in spring and peaked in summer, following the seasonal growing cycle, while endotoxins peaked in autumn during the row crop harvesting season. Paired comparisons of bioaerosols in urban and background sites revealed significant urban enhancements in PM10, fungal glucans, endotoxins, and water-soluble proteins relative to background locations, such that urban populations have a greater outdoor exposure to bioaerosols. These bioaerosols contribute, in part, to the urban excesses in PM10. Higher bioaerosol mass fractions in urban areas relative to background sites indicate that urban areas serve as a source of bioaerosols. Similar urban enhancements in water-soluble calcium and its correlation with bioaerosol tracers point toward windblown soil as an important source of bioaerosols in urban areas.

  6. The relation between isolated tree brightness temperature and grass background brightness temperature

    NASA Astrophysics Data System (ADS)

    Krusinger, A. E.

    1983-08-01

    This study involves thermal infrared measurement for the determination of the diurnal and seasonal aspects of the relations between isolated evergreen tress and a cut grass background and between a large truck brightness temperature and cut grass, uncut grass, and bare soil backgrounds. Seasonal changes in the tree brightness temperature-background brightness temperature contrast ranged from 4 to 5 C in February and March to 1 to 2 C in July. At night, the thermal contrast between trees and background was found to vary inversely with long wave incoming radiation, which is a measure of cloudiness. A study of the change in the thermal contrast during the night showed that, during clear weather, the contrast was at a peak a few hours after sundown and decreased the rest of the night. In overcast conditions, a reduced contrast peak occurred at sundown and very gradually diminished through the night. Isothermal conditions were found to occur in the early mornings, and the time of these occurrences changed seasonally, in a systematic manner.

  7. Is low empathy related to bullying after controlling for individual and social background variables?

    PubMed

    Jolliffe, Darrick; Farrington, David P

    2011-02-01

    This paper examines the relationship between low empathy and bullying while also controlling for the impact of a number of other individual and social background variables linked with bullying. This included the relationship to the prevalence of bullying, but also to the frequency and type of bullying. Questionnaires were completed by 720 adolescents (344 females, 376 males) aged 13-17 in three secondary schools in England. The results suggested that low affective empathy was independently related to bullying by males, but not females. There was no evidence that low cognitive empathy was independently related to bullying, but high impulsivity was related to all forms of male bullying and to female bullying. The implications of the findings for research and practice are discussed. PMID:20202677

  8. On the relative roles of background selection and genetic hitchhiking in shaping human cytomegalovirus genetic diversity.

    PubMed

    Renzette, Nicholas; Kowalik, Timothy F; Jensen, Jeffrey D

    2016-01-01

    A central focus of population genetics has been examining the contribution of selective and neutral processes in shaping patterns of intraspecies diversity. In terms of selection specifically, surveys of higher organisms have shown considerable variation in the relative contributions of background selection and genetic hitchhiking in shaping the distribution of polymorphisms, although these analyses have rarely been extended to bacteria and viruses. Here, we study the evolution of a ubiquitous, viral pathogen, human cytomegalovirus (HCMV), by analysing the relationship among intraspecies diversity, interspecies divergence and rates of recombination. We show that there is a strong correlation between diversity and divergence, consistent with expectations of neutral evolution. However, after correcting for divergence, there remains a significant correlation between intraspecies diversity and recombination rates, with additional analyses suggesting that this correlation is largely due to the effects of background selection. In addition, a small number of loci, centred on long noncoding RNAs, also show evidence of selective sweeps. These data suggest that HCMV evolution is dominated by neutral mechanisms as well as background selection, expanding our understanding of linked selection to a novel class of organisms. PMID:26211679

  9. Selection of renal background for quantitative 131I-hippurate relative renal function studies.

    PubMed

    Rosenthall, L; Damtew, B; Kloiber, R

    1981-01-01

    In a series of 100 patients with a full range of normal to poor renal function it was found, using 99mTC--albumin, that the zone between the superior poles of the kidneys best approximates the vascular pool in the renal areas. It is therefore possible to perform sufficiently accurate background-corrected relative renal function studies with 131I-hippurate alone. It is most valid in monitoring renal function in follow-up examinations. Both the accumulated 1- to 2-min count and 0- to 3-min count of the estimated net 131I-hippurate renogram were compared to a standard 99mTc-albumin corrected 131I-hippurate renogram for relative renal function measurements and they correlated very well (r = 0.91). The integrated 0- to 3-min count is preferred to the integrated 1- to 2-min count as the former yields better counting statistics, particularly in renal failure. PMID:7261857

  10. Lensed cosmic microwave background constraints on post-general-relativity parameters

    SciTech Connect

    Serra, Paolo; Cooray, Asantha; Daniel, Scott F.; Caldwell, Robert; Melchiorri, Alessandro

    2009-05-15

    The constraints on departures from general relativity (GR) at cosmological length scales due to cosmic microwave background (CMB) data are discussed. The departure from GR is measured by the ratio, parametrized as 1+{pi}{sub 0}(1+z){sup -S}, between the gravitational potentials conventionally appearing in the geodesic equation and the Poisson equation. Current CMB data indicate {pi}{sub 0}=1.67{sub -1.87}{sup +3.07} at the 2{sigma} confidence level, while S remains unconstrained. The departure from GR affects the lensing conversion of E-mode into B-mode polarization. Hence, the lensing measurements from CMBpol alone should be able to improve the constraint to {pi}{sub 0}<0.52 (2{sigma}) for a fiducial {pi}{sub 0}=0 model independent of S.

  11. Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

    PubMed Central

    Abeles, Ilana Y.; Gomez-Ramirez, Manuel

    2014-01-01

    Studies show that patients with schizophrenia exhibit impaired responses to sensory stimuli, especially at the early stages of neural processing. In particular, patients’ alpha-band (8–14 Hz) event-related desynchronization (ERD) and visual P1 event-related potential (ERP) component tend to be significantly reduced, with P1 ERP deficits greater for visual stimuli biased towards the magnocellular system. In healthy controls, studies show that pre-stimulus alpha (background alpha) plays a pivotal role in sensory processing and behavior, largely by shaping the neural responses to incoming stimuli. Here, we address whether patients’ ERD and P1 deficits stem from impairments in pre-stimulus alpha mechanisms. To address this question we recorded electrophysiological activity in patients with schizophrenia and healthy controls while they engaged in a visual discrimination task with low, medium, and high contrast stimuli. The results revealed a significant decrease in patients’ ERDs, which was largely driven by reductions in pre-stimulus alpha. These reductions were most prominent in right-hemispheric areas. We also observed a systematic relationship between pre-stimulus alpha and the P1 component across different contrast levels. However, this relationship was only observed in healthy controls. Taken together, these findings highlight a substantial anomaly in patients’ amplitude-based alpha background activity over visual areas. The results provide further support that pre-stimulus alpha activity plays an active role in perception by modulating the neural responses to incoming sensory inputs, a mechanism that seems to be compromised in schizophrenia. PMID:24646909

  12. From Cleanup to Stewardship. A companion report to Accelerating Cleanup: Paths to Closure and background information to support the scoping process required for the 1998 PEIS Settlement Study

    SciTech Connect

    1999-10-01

    Long-term stewardship is expected to be needed at more than 100 DOE sites after DOE's Environmental Management program completes disposal, stabilization, and restoration operations to address waste and contamination resulting from nuclear research and nuclear weapons production conducted over the past 50 years. From Cleanup to stewardship provides background information on the Department of Energy (DOE) long-term stewardship obligations and activities. This document begins to examine the transition from cleanup to long-term stewardship, and it fulfills the Secretary's commitment to the President in the 1999 Performance Agreement to provide a companion report to the Department's Accelerating Cleanup: Paths to Closure report. It also provides background information to support the scoping process required for a study on long-term stewardship required by a 1998 Settlement Agreement.

  13. The occurrence and seasonal variation of accelerant-related burn injuries in central Florida.

    PubMed

    Rainey, Susan; Cruse, C Wayne; Smith, Jackie S; Smith, Kirk R; Jones, Dawn; Cobb, Sarah

    2007-01-01

    Accidental burn injuries result in significant economic and public health burdens. The inappropriate use of gasoline and other accelerants has been identified in many studies as dangerous, yet it remains an all-too-common practice resulting in a significant number of injuries annually. Florida's unique climate permits outdoor recreational and maintenance activities, such as burning yard debris and other trash, throughout the year. Additionally, the hurricane season, lasting from June 1 though November 30, produces large amounts of waste in its wake. The purpose of this study was to examine the seasonal pattern of occurrence and develop an understanding of factors related to accelerant-related burn injuries with the goal of prevention. This nonexperimental research involved a retrospective quantitative observational study of data stored in the National Trauma Registry database. All burn patients admitted to the Tampa General Regional Burn Center as inpatients between January 1, 2001, and December 31, 2005, were included. As with previous studies on the occurrence of accelerant related injuries, young men were much more likely to suffer this type of injury. The hurricane season correlates with an increased number of accelerant related burn injuries, which differs somewhat from the seasonal variations in other regions. The size and severity of accelerant-related injuries varies significantly, as does the length of hospital stay. Accelerant use is frequently associated with trash/brush-related accidents. Hurricane seasons can produce an inordinately large amount of debris and therefore are related with an increased incident in this type of burn injury. The results of this study support the development of a community-based educational program directed at burn injury prevention, with special attention to the implications of the hurricane season. PMID:17667487

  14. An accelerated lambda iteration method for multilevel radiative transfer. I - Non-overlapping lines with background continuum

    NASA Technical Reports Server (NTRS)

    Rybicki, G. B.; Hummer, D. G.

    1991-01-01

    A method is presented for solving multilevel transfer problems when nonoverlapping lines and background continuum are present and active continuum transfer is absent. An approximate lambda operator is employed to derive linear, 'preconditioned', statistical-equilibrium equations. A method is described for finding the diagonal elements of the 'true' numerical lambda operator, and therefore for obtaining the coefficients of the equations. Iterations of the preconditioned equations, in conjunction with the transfer equation's formal solution, are used to solve linear equations. Some multilevel problems are considered, including an eleven-level neutral helium atom. Diagonal and tridiagonal approximate lambda operators are utilized in the problems to examine the convergence properties of the method, and it is found to be effective for the line transfer problems.

  15. Voice Relative Fundamental Frequency via Neck-Skin Acceleration in Individuals with Voice Disorders

    ERIC Educational Resources Information Center

    Lien, Yu-An S.; Calabrese, Carolyn R.; Michener, Carolyn M.; Murray, Elizabeth Heller; Van Stan, Jarrad H.; Mehta, Daryush D.; Hillman, Robert E.; Noordzij, J. Pieter; Stepp, Cara E.

    2015-01-01

    Purpose: This study investigated the use of neck-skin acceleration for relative fundamental frequency (RFF) analysis. Method: Forty individuals with voice disorders associated with vocal hyperfunction and 20 age- and sex-matched control participants were recorded with a subglottal neck-surface accelerometer and a microphone while producing speech…

  16. Variables Related to Outcomes of Engineering Students of Differing Occupational-Educational Backgrounds.

    ERIC Educational Resources Information Center

    Roth, John D.

    This study explored the relationship between the occupational-educational background of engineering students and outcome after one year of college. The variables of ability, financial aid, part-time employment, and residence were explored to determine their effect on the relationship between occupational-educational background and outcomes.…

  17. The Role of Cultural Background and Team Divisions in Developing Social Learning Relations in the Classroom

    ERIC Educational Resources Information Center

    Rienties, Bart; Nanclares, Núria Hernández; Jindal-Snape, Divya; Alcott, Peter

    2013-01-01

    A common assumption is that students prefer to work together with students from similar cultural backgrounds. In a group work context, students from different cultural backgrounds are "forced" to work together. This might lead to stress and anxiety but at the same time may allow students to learn from different perspectives. The prime…

  18. Modern Simulation and Optimization Tools for Non-Scaling FFAGs and Related Accelerators

    SciTech Connect

    C. Johnstone; M. Berz; K. Makino

    2010-11-04

    With the U.S. experimental effort in HEP largely located at laboratories supporting the operations of large, highly specialized accelerators, the understanding and prediction of high energy particle accelerators becomes critical to the overall success of the DOE HEP program. One area in which small businesses can contribute to the ongoing success of the U.S. program in HEP is through innovations in computer techniques and sophistication in the modeling of high-energy accelerators. A specific newly identified problem lies in the simulation and optimization of FFAGs and related devices, for which currently available tools originally developed for other purposes provide only approximate and inefficient simulation. We propose to develop a set of tools for this purpose based on modern techniques and simulation approaches.

  19. Models of Accelerated Sarcopenia: Critical Pieces for Solving the Puzzle of Age-Related Muscle Atrophy

    PubMed Central

    Buford, Thomas W.; Anton, Stephen D.; Judge, Andrew R.; Marzetti, Emanuele; Wohlgemuth, Stephanie E; Carter, Christy S.; Leeuwenburgh, Christiaan; Pahor, Marco; Manini, Todd M.

    2013-01-01

    Sarcopenia, the age-related loss of skeletal muscle mass, is a significant public health concern that continues to grow in relevance as the population ages. Certain conditions have the strong potential to coincide with sarcopenia to accelerate the progression of muscle atrophy in older adults. Among these conditions are co-morbid diseases common to older individuals such as cancer, kidney disease, diabetes, and peripheral artery disease. Furthermore, behaviors such as poor nutrition and physical inactivity are well-known to contribute to sarcopenia development. However, we argue that these behaviors are not inherent to the development of sarcopenia but rather accelerate its progression. In the present review, we discuss how these factors affect systemic and cellular mechanisms that contribute to skeletal muscle atrophy. In addition, we describe gaps in the literature concerning the role of these factors in accelerating sarcopenia progression. Elucidating biochemical pathways related to accelerated muscle atrophy may allow for improved discovery of therapeutic treatments related to sarcopenia. PMID:20438881

  20. Characteristics of myosin profile in human vastus lateralis muscle in relation to training background.

    PubMed

    Zawadowska, B; Majerczak, J; Semik, D; Karasinski, J; Kolodziejski, L; Kilarski, W M; Duda, K; Zoladz, J A

    2004-01-01

    Twenty-four male volunteers (mean +/- SD: age 25.4+/-5.8 years, height 178.6+/-5.5 cm, body mass 72.1+/-7.7 kg) of different training background were investigated and classified into three groups according to their physical activity and sport discipline: untrained students (group A), national and sub-national level endurance athletes (group B, 7.8+/-2.9 years of specialised training) and sprint-power athletes (group C, 12.8+/-8.7 years of specialised training). Muscle biopsies of vastus lateralis were analysed histochemically for mATPase and SDH activities, immunohistochemically for fast and slow myosin, and electrophoretically followed by Western immunoblotting for myosin heavy chain (MyHC) composition. Significant differences (P<0.05) regarding composition of muscle fibre types and myosin heavy chains were found only between groups A (41.7+/-1.6% of MyHCI, 40.8+/-4.0% of MyHCIIA and 17.5+/-4.0% of MyHCIIX) and B (64.3+/-0.8% of MyHCI, 34.0+/-1.4% of MyHCIIA and 1.7+/-1.4% of MyHCIIX) and groups A and C (59.6+/-1.6% of MyHCI, 37.2+/-1.3% of MyHCIIA and 3.2+/-1.3% of MyHCIIX). Unexpectedly, endurance athletes (group B) such as long-distance runners, cyclists and cross country skiers, did not differ from the athletes representing short term, high power output sports (group C) such as ice hockey, karate, ski-jumping, volleyball, soccer and modern dance. Furthermore, the relative amount of the fastest MyHCIIX isoform in vastus lateralis muscle was significantly lower in the athletes from group C than in students (group A). We conclude that the myosin profile in the athletes belonging to group C was unfavourable for their sport disciplines. This could be the reason why those athletes did not reach international level despite of several years of training. PMID:15493580

  1. Machine-Related Backgrounds in the SiD Detector at ILC

    SciTech Connect

    Denisov, D.S.; Mokhov, N.V.; Striganov, S.I.; Kostin, M.A.; Tropin, I.S.; /Tomsk Polytechnic U.

    2006-08-01

    With a multi-stage collimation system and magnetic iron spoilers in the tunnel, the background particle fluxes on the ILC detector can be substantially reduced. At the same time, beam-halo interactions with collimators and protective masks in the beam delivery system create fluxes of muons and other secondary particles which can still exceed the tolerable levels for some of the ILC sub-detectors. Results of modeling of such backgrounds in comparison to those from the e{sup +}e{sup -} interactions are presented in this paper for the SiD detector.

  2. Determination of the Cosmic Radio Background from the Radio-Infrared Relation in Galaxies

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Barker, Michael K.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We use the radioactive flux correlation for star forming galaxies in the local universe to derive their contribution to the cosmic radio background (CRB). The CRB from these galaxies is therefore determined by the evolution of the comoving infrared luminosity density with redshift, which is constrained by galaxy number counts at various infrared wavelengths and by the cosmic infrared background. The research of ED was supported by NASA NRA 99-OSS-01 Astrophysics Theory Program. MB acknowledges the support of the "Research Opportunities for Undergraduates in the Laboratory for Astronomy and Solar Physics" for the summer student internship program at NASA/GSFC.

  3. Is Low Empathy Related to Bullying after Controlling for Individual and Social Background Variables?

    ERIC Educational Resources Information Center

    Jolliffe, Darrick; Farrington, David P.

    2011-01-01

    This paper examines the relationship between low empathy and bullying while also controlling for the impact of a number of other individual and social background variables linked with bullying. This included the relationship to the prevalence of bullying, but also to the frequency and type of bullying. Questionnaires were completed by 720…

  4. Differential Relations between Facets of Complex Problem Solving and Students' Immigration Background

    ERIC Educational Resources Information Center

    Sonnleitner, Philipp; Brunner, Martin; Keller, Ulrich; Martin, Romain

    2014-01-01

    Whereas the assessment of complex problem solving (CPS) has received increasing attention in the context of international large-scale assessments, its fairness in regard to students' cultural background has gone largely unexplored. On the basis of a student sample of 9th-graders (N = 299), including a representative number of immigrant students (N…

  5. Geochemical background of antimony and thallium and its possible relation to soil properties

    NASA Astrophysics Data System (ADS)

    Pérez-Sirvent, C.; Martínez-Sánchez, M. J.; Molina, J.; García-Lorenzo, M. L.; Hernandez-Cordoba, M.

    2009-04-01

    Background value for trace elements in soils can act as a true reference level for estimating the extent of soil pollution with these elements. Background value is highly dependent on the mineralogical composition of the parent material and on the weathering processes that have led to the formation of the soil clay, and organic matter content. In recent years, environmental geochemical mapping has assumed an increasing relevance. Geochemical maps are of great interest because they constitute an effective tool for environmental planning, and for promoting sustainable development. This explains why, in recent years, many governments have promoted research to define geochemical background and baseline levels to serve as a basis for legislation to diagnose, prevent and reduce soil contamination. The objective of this study was to determine the selenium background and baseline values in agricultural soils or abandoned agricultural soils with natural vegetation not subjected to particular point contamination sources, in the Region of Murcia (SE, Spain). Moreover, the purpose of this paper was to study the possible relationship between soil properties, mineralogical composition and selenium content in soil samples. This work seeks to establish the geochemical background for thallium and antimony in the province of Murcia. The possible relationship between soil properties and target metals concentration has been studied. In the present study, background concentrations were established by analysing a large number of samples soils considered unaffected, or at least minimally affected, by human activities. Samples were analysed for antimony content by atomic fluorescence spectrometry (AFS) and by inductively coupled plasma spectrometry (ICP-MS) for thallium content. Other soil characteristics such as electrical conductivity (EC), organic matter (OM), pH, soluble salts, granulometry and calcium carbonate content were also measured to determine their influence on trace element

  6. Testing the Impact of Job-Related Variables on a Utility Judgment Training Criterion beyond Background and Affective Reaction Variables

    ERIC Educational Resources Information Center

    Blau, Gary; Gibson, Greg; Bentley, Melissa; Chapman, Susan

    2012-01-01

    We tested the incremental impact of a job-related set of variables for explaining a utility judgment training effectiveness variable, that is, course completion skill preparedness, beyond background and course-related variables. Our respondents were two different emergency medical service samples, 415 basics and 742 paramedics, from the 2008 US…

  7. A Study of the Self-Esteem and Related Background Factors of New Reformatory Inmates.

    ERIC Educational Resources Information Center

    Johnson, Robert Edwin

    The purposes of this study were to examine whether the self-esteem of inmates is low when compared with the self-esteem of a civilian population, and to examine twelve inmate background factors that might influence inmate self-esteem at the time of incarceration. The population consisted of 153 Negro and 182 white 17-22 year old "first-timers"…

  8. Relation of EEG alpha background to cognitive fuction, brain atrophy, and cerebral metabolism in Down's syndrome. Age-specific changes

    SciTech Connect

    Devinsky, O.; Sato, S.; Conwit, R.A.; Schapiro, M.B. )

    1990-01-01

    We studied 19 young adults (19 to 37 years old) and 9 older patients (42 to 66 years old) with Down's syndrome (DS) and a control group of 13 healthy adults (22 to 38 years old) to investigate the relation of electroencephalographic (EEG) alpha background to cognitive function and cerebral metabolism. Four of the older patients with DS had a history of mental deterioration, disorientation, and memory loss and were demented. Patients and control subjects had EEGs, psychometric testing, quantitative computed tomography, and positron emission tomography with fludeoxyglucose F 18. A blinded reader classified the EEGs into two groups--those with normal alpha background or those with abnormal background. All the control subjects, the 13 young adult patients with DS, and the 5 older patients with DS had normal EEG backgrounds. In comparison with the age-matched patients with DS with normal alpha background, older patients with DS with decreased alpha background had dementia, fewer visuospatial skills, decreased attention span, larger third ventricles, and a global decrease in cerebral glucose utilization with parietal hypometabolism. In the young patients with DS, the EEG background did not correlate with psychometric or positron emission tomographic findings, but the third ventricles were significantly larger in those with abnormal EEG background. The young patients with DS, with or without normal EEG background, had positron emission tomographic findings similar to those of the control subjects. The mechanism underlying the abnormal EEG background may be the neuropathologic changes of Alzheimer's disease in older patients with DS and may be cerebral immaturity in younger patients with DS.

  9. Deformed special relativity as an effective theory of measurements on quantum gravitational backgrounds

    SciTech Connect

    Aloisio, R.; Grillo, A.; Galante, A.; Liberati, S.; Luzio, E.; Mendez, F.

    2006-02-15

    In this article we elaborate on a recently proposed interpretation of deformed special relativity (DSR) as an effective measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations. We provide several heuristic arguments to explain how such a new theory can emerge and discuss the possible observational consequences of this framework. Given that our discussion considers leading order corrections to the standard dispersion relations, our results apply to a very wide class of possible modifications of special relativity.

  10. High Availability On-line Relational Databases for Accelerator Control and Operation

    SciTech Connect

    Dohan,D.; Dalesio, L.; Carcassi, G.

    2009-05-04

    The role that relational database (RDB) technology plays in accelerator control and operation continues to grow in such areas as electronic logbooks, machine parameter definitions, and facility infrastructure management. RDBs are increasingly relied upon to provide the official 'master' copy of these data. Whereas the services provided by the RDB have traditionally not been 'mission critical', the availability of modern RDB management systems is now equivalent to that of standard computer file-systems. RDBs can be relied on to supply pseudo real-time response to operator and machine physicist requests. This paper describes recent developments in the IRMIS RDB project. Generic lattice support has been added, serving as the driver for model-based machine control. Abstract physics name service and process variable introspection has been added. Specific emphasis has been placed both on providing fast response time to accelerator operators and modeling code requests, as well as high (24/7) availability of the RDB service.

  11. MeCP2 Related Studies Benefit from the Use of CD1 as Genetic Background

    PubMed Central

    Cobolli Gigli, Clementina; Scaramuzza, Linda; Gandaglia, Anna; Bellini, Elisa; Gabaglio, Marina; Parolaro, Daniela; Kilstrup-Nielsen, Charlotte; Bedogni, Francesco

    2016-01-01

    MECP2 mutations cause a number of neurological disorders of which Rett syndrome (RTT) represents the most thoroughly analysed condition. Many Mecp2 mouse models have been generated through the years; their validity is demonstrated by the presence of a broad spectrum of phenotypes largely mimicking those manifested by RTT patients. These mouse models, between which the C57BL/6 Mecp2tm1.1Bird strain probably represents the most used, enabled to disclose much of the roles of Mecp2. However, small litters with little viability and poor maternal care hamper the maintenance of the colony, thus limiting research on such animals. For this reason, past studies often used Mecp2 mouse models on mixed genetic backgrounds, thus opening questions on whether modifier genes could be responsible for at least part of the described effects. To verify this possibility, and facilitate the maintenance of the Mecp2 colony, we transferred the Mecp2tm1.1Bird allele on the stronger CD1 background. The CD1 strain is easier to maintain and largely recapitulates the phenotypes already described in Mecp2-null mice. We believe that this mouse model will foster the research on RTT. PMID:27097329

  12. Vapor intrusion attenuation factors relative to subslab and source, reconsidered in light of background data

    PubMed Central

    Yao, Yijun; Wu, Yun; Suuberg, Eric M.; Provoost, Jeroen; shen, Rui; Ma, Jianqing; Liu, Jing

    2016-01-01

    The basis upon which recommended attenuation factors for vapor intrusion (VI) have been derived are reconsidered. By making a fitting curve to the plot showing the dependence of observed indoor air concentration (cin) on subslab concentration (css) for residences in EPA database, an analytical equation is obtained to identify the relationship among cin, css and the averaged background level. The new relationship indicates that subslab measurements may serve as a useful guide only if css is above 500 μg / m3. Otherwise, cin is independent of css, with a distribution in good agreements with other studies of background levels. Therefore, employing this screening value (500 μg / m3), new contaminant concentration attenuation factors are proposed for VI, and the values for groundwater-to-indoor and subslab-to-indoor air concentration attenuation factors are 0.004 and 0.02, respectively. The former is applied to examining the reported temporal variations of cin obtained during a long-term monitoring study. The results show that using this new groundwater-to-indoor air concentration attenuation factor also provides a reasonably conservative estimate of cin. PMID:25618001

  13. MeCP2 Related Studies Benefit from the Use of CD1 as Genetic Background.

    PubMed

    Cobolli Gigli, Clementina; Scaramuzza, Linda; Gandaglia, Anna; Bellini, Elisa; Gabaglio, Marina; Parolaro, Daniela; Kilstrup-Nielsen, Charlotte; Landsberger, Nicoletta; Bedogni, Francesco

    2016-01-01

    MECP2 mutations cause a number of neurological disorders of which Rett syndrome (RTT) represents the most thoroughly analysed condition. Many Mecp2 mouse models have been generated through the years; their validity is demonstrated by the presence of a broad spectrum of phenotypes largely mimicking those manifested by RTT patients. These mouse models, between which the C57BL/6 Mecp2tm1.1Bird strain probably represents the most used, enabled to disclose much of the roles of Mecp2. However, small litters with little viability and poor maternal care hamper the maintenance of the colony, thus limiting research on such animals. For this reason, past studies often used Mecp2 mouse models on mixed genetic backgrounds, thus opening questions on whether modifier genes could be responsible for at least part of the described effects. To verify this possibility, and facilitate the maintenance of the Mecp2 colony, we transferred the Mecp2tm1.1Bird allele on the stronger CD1 background. The CD1 strain is easier to maintain and largely recapitulates the phenotypes already described in Mecp2-null mice. We believe that this mouse model will foster the research on RTT. PMID:27097329

  14. Integration and health-related quality of life of undergraduate medical students with migration backgrounds – Results of a survey

    PubMed Central

    Kurré, Jennifer; Scholl, Johanna; Bullinger, Monika; Petersen-Ewert, Corinna

    2011-01-01

    Objective: Most medical faculties in Germany are still lacking differentiated counseling programmes for specific target groups. The purpose of the present study was to determine the quality of life and integration of students with migration backgrounds and their interests in counseling programmes. Methods: Data was collected at the University Medical Center Hamburg-Eppendorf in Germany. Participants were students of the undergraduate medical course; n=890 (89.3%) students without migration backgrounds were compared to n=107 (10.7%) students with an existing migration background. Results: The results showed that medical students with migration backgrounds reported lower scores for health-related quality of life compared to students without a migration background. They felt less accepted and supported by their fellow students and had fewer contacts with other students. Medical students with migration backgrounds were characterised by a higher interest in the implementation of a counseling programme (Z=–3.420; p=.001). Conclusions: In summary, medical students with migration backgrounds were identified as a group with an increased need for a specific counseling service. Lower scores of mental health and feelings of inferior integration set the necessity for early counseling and intervention needs. PMID:22049300

  15. Can Massive Gravity Explain the Mass Discrepancy-Acceleration Relation of Disk Galaxies?

    NASA Astrophysics Data System (ADS)

    Trippe, Sascha

    2013-06-01

    The empirical mass discrepancy-acceleration (MDA) relation of disk galaxies provides a key test for models of galactic dynamics. In terms of modified laws of gravity and/or inertia, the MDA relation quantifies the transition from Newtonian to modified dynamics at low centripetal accelerations a_c≲10^{-10} m s^{-2}. As yet, neither dynamical models based on dark matter nor proposed modifications of the laws of gravity/inertia have predicted the functional form of the MDA relation. In this work, I revisit the MDA data and compare them to four different theoretical scaling laws. Three of these scaling laws are entirely empirical; the fourth one - the ``simple μ'' function of Modified Newtonian Dynamics - derives from a toy model of gravity based on massive gravitons (the ``graviton picture''). All theoretical MDA relations comprise one free parameter of the dimension of an acceleration, Milgrom's constant am. I find that the ``simple μ'' function provides a good fit to the data free of notable systematic residuals and provides the best fit among the four scaling laws tested. The best-fit value of Milgrom's constant is am=(1.06±0.05)×10^{-10} m s^{-2}. Given the successful prediction of the functional form of the MDA relation, plus an overall agreement with the observed kinematics of stellar systems spanning eight orders of magnitude in size and 14 orders of magnitude in mass, I conclude that the ``graviton picture'' is sufficient (albeit probably not a necessary nor unique approach) to describe galactic dynamics on all scales well beyond the scale of the solar system. This suggests that, at least on galactic scales, gravity behaves as if it was mediated by massive particles.

  16. Within- and Cross-Language Relations between Oral Language Proficiency and School Outcomes in Bilingual Children with an Immigrant Background

    ERIC Educational Resources Information Center

    Prevoo, Mariëlle J. L.; Malda, Maike; Mesman, Judi; van IJzendoorn, Marinus H.

    2016-01-01

    Sixteen meta-analyses were conducted to examine relations of typically developing bilingual immigrant-background children's oral language proficiency in their first and second language with the school outcomes of early literacy (k = 41), reading (k = 61), spelling (k = 9), mathematics (k = 9), and academic achievement (k = 9). Moderate to strong…

  17. Spatial Relationships of Auroral Particle Acceleration Relative to High Latitude Plasma Boundaries

    NASA Technical Reports Server (NTRS)

    Ghielmetti, Arthur G.

    1997-01-01

    This final report describes the activities under NASA contract to Lockheed Missiles and Space Company. It covers the period from 10-1-94 to 12-31-97. The objective of this investigation is to identify and characterize the spatial relationships of auroral particle acceleration features relative to the characteristic transition features in the surrounding polar ionospheric plasmas. Due to the reduced funding level approved for this contract, the original scope of the proposed work was readjusted with the focus placed on examining spatial relationships with respect to particle structures.

  18. Heterogeneity of Relational Backgrounds is Associated With Variation in Non-Suicidal Self-Injurious Behavior.

    PubMed

    Martin, Jodi; Bureau, Jean-François; Yurkowski, Kim; Lafontaine, Marie-France; Cloutier, Paula

    2016-04-01

    Non-suicidal self-injury (NSSI) is a self-destructive behavior of common prevalence in adolescence and young adulthood. Engagement in NSSI has been consistently linked in the literature with perceptions of one's parent-child relationships as negative or invalidating. However, the potential for multiple combinations of such relational characteristics to be associated with varying cognitive and behavioral manifestations of NSSI remains uninvestigated. In the current study, a person-centered approach to studying perceived parent-child relationship quality and NSSI was adopted; functions and behavioral severity of NSSI were then compared across the different relational profiles created. A latent profile analysis in a sample of 264 self-injuring university students (205 females; m(age) = 19.37 years, sd = 1.50) revealed four distinct profiles, two characterized by negative parent-child perceptions and two by positive parent-child perceptions. The perceived relational dimensions of these profiles were unique compared to a parallel group of 264 non-self-injurers (207 females; m(age) = 19.27 years, sd = 1.33). Participants reporting negative parent-child relationships endorsed more severe NSSI, and engaged in NSSI to regulate aggressive emotions. In contrast, individuals reporting positive parent-child relationships engaged in less extreme manifestations of NSSI overall, suggesting lower psychological deficits. Findings suggest that, although not all self-injurers perceive their relationships with parents negatively, variation in the perception of relational quality is implicated in behavioral and cognitive variation in NSSI engagement. PMID:26133094

  19. Natural and accelerated CO{sub 2} binding kinetics in cement paste at different relative humidities

    SciTech Connect

    Galan, Isabel; Andrade, Carmen; Castellote, Marta

    2013-07-15

    Natural carbonation and accelerated carbonation are compared in terms of CO{sub 2} combination. Thermogravimetrical analysis, neutron diffraction and weight measurements were used to quantify the amounts of CO{sub 2} in samples exposed to different CO{sub 2} and relative humidity (RH) conditions. An exponential equation is proposed to describe temporal evolution: combination rates and maximum values are obtained both for natural and accelerated processes. The influence of RH in these parameters is analyzed. At 100% CO{sub 2} an increase of RH from 53 to 75% diminishes the combination rate considerably, but increases slightly the maximum CO{sub 2} binding. At 0.5% CO{sub 2} both the rate and the maximum are higher for intermediate RH, with a linear relation between both variables. Equivalences between the different processes have been calculated: the amount of CO{sub 2} combined in 1 h at 100% CO{sub 2} and 65% RH carbonation is equivalent to approximately 36 days of natural exposure outside and 54 days inside.

  20. Acceleration of Electron Repulsion Integral Evaluation on Graphics Processing Units via Use of Recurrence Relations.

    PubMed

    Miao, Yipu; Merz, Kenneth M

    2013-02-12

    Electron repulsion integral (ERI) calculation on graphical processing units (GPUs) can significantly accelerate quantum chemical calculations. Herein, the ab initio self-consistent-field (SCF) calculation is implemented on GPUs using recurrence relations, which is one of the fastest ERI evaluation algorithms currently available. A direct-SCF scheme to assemble the Fock matrix efficiently is presented, wherein ERIs are evaluated on-the-fly to avoid CPU-GPU data transfer, a well-known architectural bottleneck in GPU specific computation. Realized speedups on GPUs reach 10-100 times relative to traditional CPU nodes, with accuracies of better than 1 × 10(-7) for systems with more than 4000 basis functions. PMID:26588740

  1. The relation between tilt table and acceleration-tolerance and their dependence on stature and physical fitness

    NASA Technical Reports Server (NTRS)

    Klein, K. E.; Backhausen, F.; Bruner, H.; Eichhorn, J.; Jovy, D.; Schotte, J.; Vogt, L.; Wegman, H. M.

    1980-01-01

    A group of 12 highly trained athletes and a group of 12untrained students were subjected to passive changes of position on a tilt table and positive accelerations in a centrifuge. During a 20 min tilt, including two additional respiratory maneuvers, the number of faints and average cardiovascular responses did not differ significantly between the groups. During linear increase of acceleration, the average blackout level was almost identical in both groups. Statistically significant coefficients of product-moment correlation for various relations were obtained. The coefficient of multiple determination computed for the dependence of acceleration tolerance on heart-eye distance and systolic blood pressure at rest allows the explanation of almost 50% of the variation of acceleration tolerance. The maximum oxygen uptake showed the expected significant correlation to the heart rate at rest, but not the acceleration tolerance, or to the cardiovascular responses to tilting.

  2. [Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

    PubMed

    Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

    2005-10-01

    Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage. PMID:16222096

  3. Social-Emotional Characteristics of Gifted Accelerated and Non-Accelerated Students in the Netherlands

    ERIC Educational Resources Information Center

    Hoogeveen, Lianne; van Hell, Janet G.; Verhoeven, Ludo

    2012-01-01

    Background: In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. Aims: In this study, social-emotional characteristics of accelerated…

  4. Accelerated Resolution Therapy for treatment of pain secondary to symptoms of combat-related posttraumatic stress disorder

    PubMed Central

    Kip, Kevin E.; Rosenzweig, Laney; Hernandez, Diego F.; Shuman, Amy; Diamond, David M.; Girling, Sue Ann; Sullivan, Kelly L.; Wittenberg, Trudy; Witt, Ann M.; Lengacher, Cecile A.; Anderson, Brian; McMillan, Susan C.

    2014-01-01

    Background As many as 70% of veterans with chronic pain treated within the US Veterans Administration (VA) system may have posttraumatic stress disorder (PTSD), and conversely, up to 80% of those with PTSD may have pain. We describe pain experienced by US service members and veterans with symptoms of PTSD, and report on the effect of Accelerated Resolution Therapy (ART), a new, brief exposure-based therapy, on acute pain reduction secondary to treatment of symptoms of PTSD. Methods A randomized controlled trial of ART versus an attention control (AC) regimen was conducted among 45 US service members/veterans with symptoms of combat-related PTSD. Participants received a mean of 3.7 sessions of ART. Results Mean age was 41.0 + 12.4 years and 20% were female. Most veterans (93%) reported pain. The majority (78%) used descriptive terms indicative of neuropathic pain, with 29% reporting symptoms of a concussion or feeling dazed. Mean pre-/post-change on the Pain Outcomes Questionnaire (POQ) was −16.9±16.6 in the ART group versus −0.7±14.2 in the AC group (p=0.0006). Among POQ subscales, treatment effects with ART were reported for pain intensity (effect size = 1.81, p=0.006), pain-related impairment in mobility (effect size = 0.69, p=0.01), and negative affect (effect size = 1.01, p=0.001). Conclusions Veterans with symptoms of combat-related PTSD have a high prevalence of significant pain, including neuropathic pain. Brief treatment of symptoms of combat-related PTSD among veterans by use of ART appears to acutely reduce concomitant pain. PMID:24959325

  5. Intrauterine growth restriction programs an accelerated age-related increase in cardiovascular risk in male offspring.

    PubMed

    Dasinger, John Henry; Intapad, Suttira; Backstrom, Miles A; Carter, Anthony J; Alexander, Barbara T

    2016-08-01

    Placental insufficiency programs an increase in blood pressure associated with a twofold increase in serum testosterone in male growth-restricted offspring at 4 mo of age. Population studies indicate that the inverse relationship between birth weight and blood pressure is amplified with age. Thus, we tested the hypothesis that intrauterine growth restriction programs an age-related increase in blood pressure in male offspring. Growth-restricted offspring retained a significantly higher blood pressure at 12 but not at 18 mo of age compared with age-matched controls. Blood pressure was significantly increased in control offspring at 18 mo of age relative to control counterparts at 12 mo; however, blood pressure was not increased in growth-restricted at 18 mo relative to growth-restricted counterparts at 12 mo. Serum testosterone levels were not elevated in growth-restricted offspring relative to control at 12 mo of age. Thus, male growth-restricted offspring no longer exhibited a positive association between blood pressure and testosterone at 12 mo of age. Unlike hypertension in male growth-restricted offspring at 4 mo of age, inhibition of the renin-angiotensin system with enalapril (250 mg/l for 2 wk) did not abolish the difference in blood pressure in growth-restricted offspring relative to control counterparts at 12 mo of age. Therefore, these data suggest that intrauterine growth restriction programs an accelerated age-related increase in blood pressure in growth-restricted offspring. Furthermore, this study suggests that the etiology of increased blood pressure in male growth-restricted offspring at 12 mo of age differs from that at 4 mo of age. PMID:27147668

  6. Responses to rotating linear acceleration vectors considered in relation to a model of the otolith organs. [human oculomotor response to transverse acceleration stress

    NASA Technical Reports Server (NTRS)

    Benson, A. J.; Barnes, G. R.

    1973-01-01

    Human subjects were exposed to a linear acceleration vector that rotated in the transverse plane of the skull without angular counterrotation. Lateral eye movements showed a sinusoidal change in slow phase velocity and an asymmetry or bias in the same direction as vector rotation. A model is developed that attributes the oculomotor response to otolithic mechanisms. It is suggested that the bias component is the manifestation of torsion of the statoconial plaque relative to the base of the utricular macula and that the sinusoidal component represents the translational oscillation of the statoconia. The model subsumes a hypothetical neural mechanism which allows x- and y-axis accelerations to be resolved. Derivation of equations of motion for the statoconial plaque in torsion and translation, which take into account forces acting in shear and normal to the macula, yield estimates of bias and sinusoidal components that are in qualitative agreement with the diverse experimental findings.

  7. APT related papers presented at the 1997 particle accelerator conference, Vancouver, May 12--16, 1997

    SciTech Connect

    Lawrence, G.

    1997-07-01

    Tritium is essential for the US nuclear weapons to function, but because it is radioactive with a half-life of 12.3 years, the supply must be periodically replenished. Presently, only reactor or accelerator systems can be used to produce tritium. This report is a compilation of 31 papers given at the 1997 Particle Accelerator Conference which dealt with the accelerator production of tritium. The papers are grouped into two categories, invited and contributed.

  8. Is age-related decline in lean mass and physical function accelerated by Obstructive Lung Disease or smoking?

    PubMed Central

    van den Borst, Bram; Koster, Annemarie; Yu, Binbing; Gosker, Harry R.; Meibohm, Bernd; Bauer, Douglas C.; Kritchevsky, Stephen B.; Liu, Yongmei; Newman, Anne B.; Harris, Tamara B.; Schols, Annemie M.W.J.

    2012-01-01

    Background and aims Cross-sectional studies suggest that Obstructive Lung Disease (OLD) and smoking affect lean mass and mobility. We aimed to investigate whether OLD and smoking accelerate aging-related decline in lean mass and physical functioning. Methods 260 persons with OLD (FEV1 63±18 %predicted), 157 smoking controls (FEV1 95±16 %predicted), 866 formerly smoking controls (FEV1 100±16 %predicted) and 891 never-smoking controls (FEV1 104±17 %predicted) participating in the Health, Aging and Body Composition (ABC) Study were studied. At baseline, the mean age was 74±3 y and participants reported no functional limitations. Baseline and seven-year longitudinal data were investigated of body composition (by Dual-energy X-ray absorptiometry), muscle strength (by hand and leg dynamometry) and Short Physical Performance Battery (SPPB). Results Compared to never-smoking controls, OLD persons and smoking controls had a significantly lower weight, fat mass, lean mass and bone mineral content (BMC) at baseline (p<0.05). While the loss of weight, fat mass, lean mass and strength was comparable between OLD persons and never-smoking controls, the SPPB declined 0.12 points/yr faster in OLD men (p=0.01) and BMC 4 g/yr faster in OLD women (p=0.02). In smoking controls, only lean mass declined 0.1 kg/yr faster in women (p=0.03) and BMC 8 g/yr faster in men (p=0.02) compared to never-smoking controls. Conclusions Initially well-functioning older adults with mild-to-moderate OLD and smokers without OLD have a comparable compromised baseline profile of body composition and physical functioning, while seven-year longitudinal trajectories are to a large extent comparable to those observed in never-smokers without OLD. This suggests a common insult earlier in life related to smoking. 3 PMID:21724748

  9. Transportation of high-current ion and electron beams in the accelerator drift gap in the presence of an additional electron background

    NASA Astrophysics Data System (ADS)

    Karas', V. I.; Kornilov, E. A.; Manuilenko, O. V.; Tarakanov, V. P.; Fedorovskaya, O. V.

    2015-12-01

    The dynamics of a high-current ion beam propagating in the drift gap of a linear induction accelerator with collective focusing is studied using 3D numerical simulations in the framework of the full system of the Vlasov-Maxwell equations (code KARAT). The ion beam is neutralized by a comoving electron beam in the current density and, partially, in space charge, since the velocities of electrons and ions differ substantially. The dynamics of the high-current ion beam is investigated for different versions of additional neutralization of its space charge. It is established that, for a given configuration of the magnetic field and in the presence of a specially programmed injection of additional electrons from the boundary opposite to the ion injection boundary, the angular divergence of the ion beam almost vanishes, whereas the current of the ion beam at the exit from the accelerator drift gap changes insignificantly and the beam remains almost monoenergetic.

  10. Transportation of high-current ion and electron beams in the accelerator drift gap in the presence of an additional electron background

    SciTech Connect

    Karas’, V. I. Kornilov, E. A.; Manuilenko, O. V.; Tarakanov, V. P.; Fedorovskaya, O. V.

    2015-12-15

    The dynamics of a high-current ion beam propagating in the drift gap of a linear induction accelerator with collective focusing is studied using 3D numerical simulations in the framework of the full system of the Vlasov–Maxwell equations (code KARAT). The ion beam is neutralized by a comoving electron beam in the current density and, partially, in space charge, since the velocities of electrons and ions differ substantially. The dynamics of the high-current ion beam is investigated for different versions of additional neutralization of its space charge. It is established that, for a given configuration of the magnetic field and in the presence of a specially programmed injection of additional electrons from the boundary opposite to the ion injection boundary, the angular divergence of the ion beam almost vanishes, whereas the current of the ion beam at the exit from the accelerator drift gap changes insignificantly and the beam remains almost monoenergetic.

  11. Voice Relative Fundamental Frequency Via Neck-Skin Acceleration in Individuals With Voice Disorders

    PubMed Central

    Lien, Yu-An S.; Calabrese, Carolyn R.; Michener, Carolyn M.; Murray, Elizabeth Heller; Van Stan, Jarrad H.; Mehta, Daryush D.; Hillman, Robert E.; Noordzij, J. Pieter

    2015-01-01

    Purpose This study investigated the use of neck-skin acceleration for relative fundamental frequency (RFF) analysis. Method Forty individuals with voice disorders associated with vocal hyperfunction and 20 age- and sex-matched control participants were recorded with a subglottal neck-surface accelerometer and a microphone while producing speech stimuli appropriate for RFF. Rater reliabilities, RFF means, and RFF standard deviations derived from the accelerometer were compared with those derived from the microphone. Results RFF estimated from the accelerometer had slightly higher intrarater reliability and identical interrater reliability compared with values estimated with the microphone. Although sensor type and the Vocal Cycle × Sensor and Vocal Cycle × Sensor × Group interactions showed significant effects on RFF means, the typical RFF pattern could be derived from either sensor. For both sensors, the RFF of individuals with vocal hyperfunction was lower than that of the controls. Sensor type and its interactions did not have significant effects on RFF standard deviations. Conclusions RFF can be reliably estimated using an accelerometer, but these values cannot be compared with those collected via microphone. Future studies are needed to determine the physiological basis of RFF and examine the effect of sensors on RFF in practical voice assessment and monitoring settings. PMID:26134171

  12. Dynamics with a Nonstandard Inertia-Acceleration Relation: An Alternative to Dark Matter in Galactic Systems

    NASA Astrophysics Data System (ADS)

    Milgrom, M.

    1994-02-01

    We investigate particle dynamics that is governed by a nonstandard kinetic action of a special form. We are guided by a phenomenological scheme-the modified dynamics (MOND)-that imputes the mass discrepancy, observed in galactic systems, not to the presence of dark matter, but to a departure from Newtonian dynamics below a certain scale of accelerations, a0. The particle's equation of motion in a potential φ is derived from an action, S, of the form S ~ Sk[r(t), a0] - ∫ φ dt. The limit a0 --> 0 corresponds to Newtonian dynamics, and there the kinetic action Sk must take the standard form. In the opposite limit, a0 --> ∞ we require Sk --> 0-and more specifically, for circular orbits Sk ~ a-10-in order to attain the phenomenological success of MOND. Galilei-invariant such theories must be strongly nonlocal. This is a blessing, as such theories need not suffer from the illnesses that are endemic to higher-derivative theories. We comment on the possibility that such a modified law of motion is an effective theory resulting from the elimination of degrees of freedom pertaining to the universe at large (the near equality a0 ≍ cH0 being a trace of that connection). We derive a general virial relation for bounded trajectories. Exact solutions are obtained for circular orbits, which pertain to rotation curves of disk galaxies. We also explore, in passing, theories that depart from the conventional Newtonian dynamics for very low frequencies.

  13. Characteristics of age-related behavioral changes in senescence-accelerated mouse SAMP8 and SAMP10.

    PubMed

    Miyamoto, M

    1997-01-01

    Senescence-Accelerated Mouse (SAM), a murine model of accelerated senescence, has been established by Takeda et al. (1981). SAM consists of senescence-accelerated-prone mouse (SAMP) and senescence-accelerated-resistant mouse (SAMR), the latter of which shows normal aging characteristics. In 1991 there were eight different substrains in the P-series, which commonly exhibited accelerated aging with a shortened life span (Takeda et al., 1991). Among the P-series, we have found that SAMP8 mice show significant impairments in a variety of learning tasks when compared with SAMR1 mice (Miyamoto et al., 1986). Further studies suggest that SAMP8 exhibits an age-related emotional disorder characterized by reduced anxiety-like behavior (Miyamoto et al., 1992). On the other hand, it has been shown that SAMP10 exhibits brain atrophy and learning impairments in an avoidance task (Shimada et al., 1992, 1993). Here, characteristics of age-related deficits in learning and memory, changes in emotional behavior, and abnormality of circadian rhythms in SAMP8 and SAMP10 mice are described. In the experiments, SAMP8/Ta (SAMP8), SAMP10/(/)Ta (SAMP10) and SAMR1TA (SAMR1) reared under specific pathogen-free conditions at Takeda Chemical Industries were used. PMID:9088911

  14. Relative Humidity in Limited Streamer Tubes for Stanford Linear Accelerator Center's BaBar Detector

    SciTech Connect

    Lang, M.I.; Convery, M.; Menges, W.; /Queen Mary, U. of London

    2005-12-15

    The BABAR Detector at the Stanford Linear Accelerator Center studies the decay of B mesons created in e{sup +}e{sup -} collisions. The outermost layer of the detector, used to detect muons and neutral hadrons created during this process, is being upgraded from Resistive Plate Chambers (RPCs) to Limited Streamer Tubes (LSTs). The standard-size LST tube consists of eight cells, where a silver-plated wire runs down the center of each. A large potential difference is placed between the wires and ground. Gas flows through a series of modules connected with tubing, typically four. LSTs must be carefully tested before installation, as it will be extremely difficult to repair any damage once installed in the detector. In the testing process, the count rate in most modules showed was stable and consistent with cosmic ray rate over an approximately 500 V operating range between 5400 to 5900 V. The count in some modules, however, was shown to unexpectedly spike near the operation point. In general, the modules through which the gas first flows did not show this problem, but those further along the gas chain were much more likely to do so. The suggestion was that this spike was due to higher humidity in the modules furthest from the fresh, dry inflowing gas, and that the water molecules in more humid modules were adversely affecting the modules' performance. This project studied the effect of humidity in the modules, using a small capacitive humidity sensor (Honeywell). The sensor provided a humidity-dependent output voltage, as well as a temperature measurement from a thermistor. A full-size hygrometer (Panametrics) was used for testing and calibrating the Honeywell sensors. First the relative humidity of the air was measured. For the full calibration, a special gas-mixing setup was used, where relative humidity of the LST gas mixture could be varied from almost dry to almost fully saturated. With the sensor calibrated, a set of sensors was used to measure humidity vs. time

  15. Genetic background influences age-related decline in visual and nonvisual retinal responses, circadian rhythms, and sleep☆

    PubMed Central

    Banks, Gareth; Heise, Ines; Starbuck, Becky; Osborne, Tamzin; Wisby, Laura; Potter, Paul; Jackson, Ian J.; Foster, Russell G.; Peirson, Stuart N.; Nolan, Patrick M.

    2015-01-01

    The circadian system is entrained to the environmental light/dark cycle via retinal photoreceptors and regulates numerous aspects of physiology and behavior, including sleep. These processes are all key factors in healthy aging showing a gradual decline with age. Despite their importance, the exact mechanisms underlying this decline are yet to be fully understood. One of the most effective tools we have to understand the genetic factors underlying these processes are genetically inbred mouse strains. The most commonly used reference mouse strain is C57BL/6J, but recently, resources such as the International Knockout Mouse Consortium have started producing large numbers of mouse mutant lines on a pure genetic background, C57BL/6N. Considering the substantial genetic diversity between mouse strains we expect there to be phenotypic differences, including differential effects of aging, in these and other strains. Such differences need to be characterized not only to establish how different mouse strains may model the aging process but also to understand how genetic background might modify age-related phenotypes. To ascertain the effects of aging on sleep/wake behavior, circadian rhythms, and light input and whether these effects are mouse strain-dependent, we have screened C57BL/6J, C57BL/6N, C3H-HeH, and C3H-Pde6b+ mouse strains at 5 ages throughout their life span. Our data show that sleep, circadian, and light input parameters are all disrupted by the aging process. Moreover, we have cataloged a number of strain-specific aging effects, including the rate of cataract development, decline in the pupillary light response, and changes in sleep fragmentation and the proportion of time spent asleep. PMID:25179226

  16. Sleep Deprivation Accelerates Delay-Related Loss of Visual Short-Term Memories Without Affecting Precision

    PubMed Central

    Wee, Natalie; Asplund, Christopher L.; Chee, Michael W. L.

    2013-01-01

    Study Objectives: Visual short-term memory (VSTM) is an important measure of information processing capacity and supports many higher-order cognitive processes. We examined how sleep deprivation (SD) and maintenance duration interact to influence the number and precision of items in VSTM using an experimental design that limits the contribution of lapses at encoding. Design: For each trial, participants attempted to maintain the location and color of three stimuli over a delay. After a retention interval of either 1 or 10 seconds, participants reported the color of the item at the cued location by selecting it on a color wheel. The probability of reporting the probed item, the precision of report, and the probability of reporting a nonprobed item were determined using a mixture-modeling analysis. Participants were studied twice in counterbalanced order, once after a night of normal sleep and once following a night of sleep deprivation. Setting: Sleep laboratory. Participants: Nineteen healthy college age volunteers (seven females) with regular sleep patterns. Interventions: Approximately 24 hours of total SD. Measurements and Results: SD selectively reduced the number of integrated representations that can be retrieved after a delay, while leaving the precision of object information in the stored representations intact. Delay interacted with SD to lower the rate of successful recall. Conclusions: Visual short-term memory is compromised during sleep deprivation, an effect compounded by delay. However, when memories are retrieved, they tend to be intact. Citation: Wee N; Asplund CL; Chee MWL. Sleep deprivation accelerates delay-related loss of visual short-term memories without affecting precision. SLEEP 2013;36(6):849-856. PMID:23729928

  17. Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss.

    PubMed

    Turner, Russell T; Dube, Michael; Branscum, Adam J; Wong, Carmen P; Olson, Dawn A; Zhong, Xiaoying; Kweh, Mercedes F; Larkin, Iske V; Wronski, Thomas J; Rosen, Clifford J; Kalra, Satya P; Iwaniec, Urszula T

    2015-12-01

    Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin, n=7) or a control vector encoding green fluorescent protein (rAAV-GFP, n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (-4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (-80%), serum leptin (-77%), and serum IGF1 (-34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover. PMID:26487675

  18. Recent US target-physics-related research in heavy-ion inertial fusion: target gains and constraints on accelerator design

    SciTech Connect

    Mark, J.W.K.

    1982-03-09

    Inertial-fusion targets were designed for use with heavy-ion accelerators as drivers in fusion energy power plants. In the interest of providing inputs for understanding the trade-offs among accelerator designs, an initial survey was carried out regarding target gain versus parameters of relevance. This was done in two stages, firstly target gain was related to the beam energy, power, focal radius, and ion range. Secondly, a more comprehensive discussion was made by posing target gain constraints on the beam-occupied phase-space volume of the linacs. This latter discussion had included some rather simplified models of accelerator final focus and beam transport in near-vacuum fusion reaction chambers. Some further analyses of the basic assumptions of this summary are also described.

  19. Mitochondrial Genetic Background Modifies the Relationship between Traffic-Related Air Pollution Exposure and Systemic Biomarkers of Inflammation

    PubMed Central

    Wittkopp, Sharine; Staimer, Norbert; Tjoa, Thomas; Gillen, Daniel; Daher, Nancy; Shafer, Martin; Schauer, James J.; Sioutas, Constantinos; Delfino, Ralph J.

    2013-01-01

    Background Mitochondria are the main source of reactive oxygen species (ROS). Human mitochondrial haplogroups are linked to differences in ROS production and oxidative-stress induced inflammation that may influence disease pathogenesis, including coronary artery disease (CAD). We previously showed that traffic-related air pollutants were associated with biomarkers of systemic inflammation in a cohort panel of subjects with CAD in the Los Angeles air basin. Objective We tested whether air pollutant exposure-associated inflammation was stronger in mitochondrial haplogroup H than U (high versus low ROS production) in this panel (38 subjects and 417 observations). Methods Inflammation biomarkers were measured weekly in each subject (≤12 weeks), including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), C-reactive protein, interleukin-6 soluble receptor and tumor necrosis factor-soluble receptor II. We determined haplogroup by restriction fragment length polymorphism analysis. Air pollutants included nitrogen oxides (NOx), carbon monoxide (CO), organic carbon, elemental and black carbon (EC, BC); and particulate matter mass, three size fractions (<0.25 µm, 0.25–2.5 µm, and 2.5–10 µm in aerodynamic diameter). Particulate matter extracts were analyzed for organic compounds, including polycyclic aromatic hydrocarbons (PAH), and in vitro oxidative potential of aqueous extracts. Associations between exposures and biomarkers, stratified by haplogroup, were analyzed by mixed-effects models. Results IL-6 and TNF-α were associated with traffic-related air pollutants (BC, CO, NOx and PAH), and with mass and oxidative potential of quasi-ultrafine particles <0.25 µm. These associations were stronger for haplogroup H than haplogroup U. Conclusions Results suggest that mitochondrial haplogroup U is a novel protective factor for air pollution-related systemic inflammation in this small group of subjects. PMID:23717615

  20. Reducing Energy-Related CO2 Emissions Using Accelerated Limestone Weathering

    SciTech Connect

    Rau, G H; Knauss, K G; Langer, W H; Caldeira, K

    2004-04-27

    Following earlier descriptions, the use and impacts of accelerated weathering of limestone AWL; reaction: CO{sub 2} + H{sub 2}O + CaCO{sub 3} {yields} Ca{sup 2+} + 2(HCO{sub 3}{sup -}) as a CO{sub 2} capture and sequestration method is further explored. Since ready access to the ocean is likely an essential requirement for AWL, it is shown that significant limestone resources are relatively close to a majority of CO{sub 2}-emitting power plants along the coastal US. Furthermore, waste fines, representing more than 20% of current US crushed limestone production (>10{sup 9} tonnes/yr), could be used in many instances as an inexpensive or free source of AWL carbonate. With limestone transportation to coastal sites then as the dominant cost variable, CO{sub 2} sequestration (plus capture) costs of $3-$4/tonne are achievable in certain locations. While there is vastly more limestone and water on earth than that required for AWL to capture and sequester all fossil fuel CO{sub 2} production, the transportation cost of bringing limestone, seawater, and waste CO{sub 2} into contact likely limits the method's applicability to perhaps 10-20% of US point-source emissions. Using a bench-scale laboratory reactor, it is shown that CO{sub 2} sequestration rates of 10{sup -6} to 10{sup -5} moles/sec per m{sup 2} of limestone surface area are readily achievable using seawater. This translates into reaction densities as high as 2 x 10{sup -2} tonnes CO{sub 2} m{sup -3}day{sup -1}, highly dependent on limestone particle size, solution turbulence and flow, and CO{sub 2} concentration. Modeling of AWL end-solution disposal in the ocean shows significantly reduced effects on ocean pH and carbonate chemistry relative to those caused by direct CO{sub 2} disposal into the atmosphere or ocean. In fact the increase in ocean Ca{sup 2+} and bicarbonate offered by AWL should significantly enhance the growth of corals and other marine calcifiers whose health is currently being threatened by

  1. CME-related particle acceleration regions during a simple eruptive event near solar minimum

    NASA Astrophysics Data System (ADS)

    Salas Matamoros, Carolina; Klein, Karl-Ludwig; Rouillard, Alexis

    2016-04-01

    An intriguing feature of many solar energetic particle (SEP) events is the detection of particles over a very extended range of longitudes in the Heliosphere. This may be due to peculiarities of the magnetic field in the corona, to a broad accelerator, to cross-field transport of the particles, or to a combination of these processes. The eruptive flare of the 26th of April 2008 offered an opportunity to study relevant processes under particularly favorable conditions, since it occurred in a very quiet solar and interplanetary environment. This allowed us to investigate the physical link between a single well-identified Coronal Mass Ejection (CME), electron acceleration as traced by radio emission, and the production of SEPs. We conduct a detailed analysis combining radio observations (Nançay Radioheliograph and Decameter Array, Wind/WAVES spectrograph) with remote-sensing observations of the corona in extreme ultraviolet (EUV) and white light as well as in-situ measurements of energetic particles near 1AU (SoHO and STEREO spacecraft). By combining images taken from multiple vantage points we were able to derive the time-dependent evolution of the 3-D pressure front developing around the erupting CME. Magnetic reconnection in the post-CME current sheet accelerated electrons that remained confined in closed magnetic fields in the corona, while the acceleration of escaping particles can be attributed to the pressure front generated ahead of the expanding CME. The CME accelerated electrons remotely from the parent active region, due to the interaction of its laterally expanding flank, traced by an EUV wave, with the ambient corona. SEPs detected at one STEREO spacecraft and SoHO were accelerated later, when the frontal shock of the CME intercepted the spacecraft-connected interplanetary magnetic field line. The injection regions into the Heliosphere inferred from the radio and SEP observations are separated in longitude by about 140°. The observations for this event

  2. Coronal mass ejection-related particle acceleration regions during a simple eruptive event

    NASA Astrophysics Data System (ADS)

    Salas-Matamoros, Carolina; Klein, Karl-Ludwig; Rouillard, Alexis P.

    2016-05-01

    An intriguing feature of many solar energetic particle (SEP) events is the detection of particles over a very extended range of longitudes in the heliosphere. This may be due to peculiarities of the magnetic field in the corona, to a broad accelerator, to cross-field transport of the particles, or to a combination of these processes. The eruptive flare on 26 April 2008 provided an opportunity to study relevant processes under particularly favourable conditions since it occurred in a very quiet solar and interplanetary environment. This enabled us to investigate the physical link between a single well-identified coronal mass ejection (CME), electron acceleration as traced by radio emission, and the production of SEPs. We conduct a detailed analysis, which combines radio observations (Nançay Radio Heliograph and Nançay Decametre Array, Wind/Waves spectrograph) with remote-sensing observations of the corona in extreme ultraviolet (EUV) and white light, as well as in situ measurements of energetic particles near 1AU (SoHO and STEREO spacecraft). By combining images taken from multiple vantage points, we were able to derive the time-dependent evolution of the 3D pressure front that was developing around the erupting CME. Magnetic reconnection in the post-CME current sheet accelerated electrons, which remained confined in closed magnetic fields in the corona, while the acceleration of escaping particles can be attributed to the pressure front ahead of the expanding CME. The CME accelerated electrons remotely from the parent active region, owing to the interaction of its laterally expanding flank, which was traced by an EUV wave, with the ambient corona. SEPs detected at one STEREO spacecraft and SoHO were accelerated later, when the frontal shock of the CME intercepted the spacecraft-connected interplanetary magnetic field line. The injection regions into the heliosphere inferred from the radio and SEP observations are separated in longitude by about 140°. The

  3. Practices of receptive and insertive anal sex among transgender women in relation to partner types, sociocultural factors, and background variables.

    PubMed

    Nemoto, Tooru; Bödeker, Birte; Iwamoto, Mariko; Sakata, Maria

    2014-04-01

    It is urgent to develop efficacious HIV prevention programs to curb the reported extremely high HIV prevalence and incidence among transgender women (male-to-female transgender persons) who reside in large cities in the USA. This study aimed to describe unprotected receptive anal sex (URAS) and unprotected insertive anal sex (UIAS) among high-risk transgender women in relation to partner types, psychosocial factors, and background variables. Based on purposive sampling from the targeted communities and AIDS service organizations in San Francisco and Oakland, a total of 573 transgender women who had a history of sex work were recruited and individually interviewed using a structured survey questionnaire. Significant correlates with URAS with primary, casual, and commercial sex partners were found (e.g., needs for social support, frequency of social support received, exposure to transphobia, self-esteem, economic pressure, norms toward practicing healthy behaviors, and self-efficacy toward practicing safe sex). Multiple logistic regression analyses revealed that transgender women who had engaged in URAS with commercial partners were more likely to have higher levels of transphobia or lower levels of the norms or self-efficacy to practice safe sex. Among the participants who did not have vaginoplasty (preoperative transgender women), 16.4% had engaged in insertive anal sex (IAS) with commercial partners in the past 30 days. The participants who were HIV positive and had engaged in IAS were more likely to be African-American or Caucasians, coinfected with sexually transmitted infections, or identified themselves as homosexual. Practices of IAS among transgender women have not been thoroughly investigated in relation to sexual and gender identity. UIAS with homosexual and bisexual men in addition to URAS may be a cause for high HIV incidence among transgender women. An HIV prevention intervention study must be developed and evaluated, which aims to reduce HIV

  4. Genetic and epigenetic background and protein expression profiles in relation to telomerase activation in medullary thyroid carcinoma

    PubMed Central

    Wang, Na; Kjellin, Hanna; Sofiadis, Anastasios; Fotouhi, Omid; Juhlin, C. Christofer; Bäckdahl, Martin; Zedenius, Jan; Xu, Dawei; Lehtiö, Janne; Larsson, Catharina

    2016-01-01

    Medullary thyroid carcinomas (MTCs) exhibit telomerase activation in strong association with shorter patient survival. To understand the background of telomerase activation we quantified TERT copy numbers and TERT promoter methylation in 42 MTCs and normal thyroid references. Gain of TERT was demonstrated by quantitative PCR in 5/39 sporadic MTC. Increased methylation index (MetI) for CpG methylation at the TERT promoter was found in sporadic MTCs (P < 0.0001) and in MEN 2 associated MTCs (P = 0.011) vs. normal thyroid tissues. MetI correlated positively with TERT gene expression (r = 0.432, P = 0.006) and negatively with telomere length (r = −0.343, P = 0.032). MTC cases with MetI above the median of 52% had shorter survival as compared to cases with lower MetI (P = 0.005 for overall survival and P = 0.007 for disease-related survival). Protein expression profiles obtained by mass spectrometry were then studied in relation to telomerase activation in MTCs. Comparing protein levels between tumors defined by telomerase activity status, 240 proteins were associated with telomerase activity. Among telomerase activation positive cases a set of proteins was found to discriminate between MTCs with high and low TERT gene expression with enrichment for proteins involved in telomerase regulation. XRCC5 mRNA expression was found increased in MTCs vs. normal thyroid (P = 0.007). In conclusion the findings suggest a role for TERT copy number gain, TERT promoter methylation and XRCC5 expression in telomerase activation and telomere maintenance of MTC. PMID:26870890

  5. Relative biological effectiveness in canine osteosarcoma cells irradiated with accelerated charged particles

    PubMed Central

    Maeda, Junko; Cartwright, Ian M.; Haskins, Jeremy S.; Fujii, Yoshihiro; Fujisawa, Hiroshi; Hirakawa, Hirokazu; Uesaka, Mitsuru; Kitamura, Hisashi; Fujimori, Akira; Thamm, Douglas H.; Kato, Takamitsu A.

    2016-01-01

    Heavy ions, characterized by high linear energy transfer (LET) radiation, have advantages compared with low LET protons and photons in their biological effects. The application of heavy ions within veterinary clinics requires additional background information to determine heavy ion efficacy. In the present study, comparison of the cell-killing effects of photons, protons and heavy ions was investigated in canine osteosarcoma (OSA) cells in vitro. A total of four canine OSA cell lines with various radiosensitivities were irradiated with 137Cs gamma-rays, monoenergetic proton beams, 50 keV/µm carbon ion spread out Bragg peak beams and 200 keV/µm iron ion monoenergetic beams. Clonogenic survival was examined using colony-forming as says, and relative biological effectiveness (RBE) values were calculated relative to gamma-rays using the D10 value, which is determined as the dose (Gy) resulting in 10% survival. For proton irradiation, the RBE values for all four cell lines were 1.0–1.1. For all four cell lines, exposure to carbon ions yielded a decreased cell survival compared with gamma-rays, with the RBE values ranging from 1.56–2.10. Iron ions yielded the lowest cell survival among tested radiation types, with RBE values ranging from 3.51–3.69 observed in the three radioresistant cell lines. The radiosensitive cell line investigated demonstrated similar cell survival for carbon and iron ion irradiation. The results of the present study suggest that heavy ions are more effective for killing radioresistant canine OSA cells when compared with gamma-rays and protons. This markedly increased efficiency of cell killing is an attractive reason for utilizing heavy ions for radioresistant canine OSA. PMID:27446477

  6. Comparison of impact forces, accelerations and ankle range of motion in surfing-related landing tasks.

    PubMed

    Lundgren, Lina E; Tran, Tai T; Nimphius, Sophia; Raymond, Ellen; Secomb, Josh L; Farley, Oliver R L; Newton, Robert U; Sheppard, Jeremy M

    2016-01-01

    This study aimed to describe the impact forces, accelerations and ankle range of motion in five different landing tasks that are used in training and testing for competitive surfing athletes, to assist coaches in the prescription of landing task progression and monitoring training load. Eleven competitive surfing athletes aged 24 ± 7 years participated, and inertial motion sensors were fixed to the anterior aspect of the feet, mid-tibial shafts, sacrum and eighth thoracic vertebrae on these athletes. Three tasks were performed landing on force plates and two tasks in a modified gymnastics set-up used for land-based aerial training. Peak landing force, resultant peak acceleration and front and rear side ankle dorsiflexion ranges of motion during landing were determined. The peak acceleration was approximately 50% higher when performing aerial training using a mini-trampoline and landing on a soft-density foam board, compared to a similar landing off a 50 cm box. Furthermore, the ankle ranges of motion during the gymnastic type landings were significantly lower than the other landing types (P ≤ 0.05 and P ≤ 0.001), for front and rear sides, respectively. Conclusively, increased task complexity and specificity of the sport increased the tibial peak acceleration, indicating greater training load. PMID:26383823

  7. Are Principal Background and School Processes Related to Teacher Job Satisfaction? A Multilevel Study Using Schools and Staffing Survey 2003-04

    ERIC Educational Resources Information Center

    Shen, Jianping; Leslie, Jeffrey M.; Spybrook, Jessaca K.; Ma, Xin

    2012-01-01

    Using nationally representative samples for public school teachers and principals, the authors inquired into whether principal background and school processes are related to teacher job satisfaction. Employing hierarchical linear modeling (HLM), the authors were able to control for background characteristics at both the teacher and school levels.…

  8. Violence against the adolescents of Kolkata: A study in relation to the socio-economic background and mental health.

    PubMed

    Deb, Sibnath; Ray, Mrinalkanti; Bhattacharyya, Banhishikha; Sun, Jiandong

    2016-02-01

    This study attempts to understand the nature of violence suffered by the adolescents of Kolkata (erstwhile Calcutta) and to identify its relation with their socio-economic background and mental health variables such as anxiety, adjustment, and self-concept. It is a cross-sectional study covering a total of 370 adolescents (182 boys and 188 girls) from six higher secondary schools in Kolkata. The data was gathered by way of a semi-structured questionnaire and three standard psychological tests. Findings revealed that 52.4%, 25.1%, and 12.7% adolescents suffered psychological, physical, and sexual violence in the last year. Older adolescents (aged 17-18 years) suffered more psychological violence than the younger ones (15-16 years) (p<0.05). Sixty nine (18.6%) adolescent students stood witness to violence between adult members in the family. More than three-fifth (61.9%) adolescents experienced at least one type of violence, while one-third (32.7%) experienced physical or sexual violence or both. Whatever its nature is, violence leaves a scar on the mental health of the victims. Those who have been through regular psychological violence reported high anxiety, emotional adjustment problem, and low self-concept. Sexual abuse left a damaging effect on self-concept (p<0.05), while psychological violence or the witnessing of violence prompted high anxiety scores (p<0.05), poor emotional adjustment (p<0.05), and low self-concept (p<0.05). This study stresses the need to provide individual counselling services to the maltreated adolescents of Kolkata so that their psychological traumas can heal and that they can move on in life with new hopes and dreams. PMID:26957328

  9. Relative biological effectiveness of accelerated heavy ions for induction of morphological transformation in Syrian hamster embryo cells.

    PubMed

    Han, Z B; Suzuki, H; Suzuki, F; Suzuki, M; Furusawa, Y; Kato, T; Ikenaga, M

    1998-09-01

    Syrian hamster embryo cells were used to study the morphological transformation induced by accelerated heavy ions with different linear energy transfer (LET) ranging from 13 to 400 keV/micron. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), then inoculated to culture dishes. Morphologically altered colonies were scored as transformants. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to X-rays first increased with LET, reached a maximum value of about 7 at 100 keV/micron, then decreased with the further increase of LET. Our findings confirmed that high LET heavy ions are much more effective than X-rays for the induction of in vitro cell transformation. PMID:9868868

  10. Accelerator-based conversion (ABC) of weapons plutonium: Plant layout study and related design issues

    SciTech Connect

    Cowell, B.S.; Fontana, M.H.; Krakowski, R.A.; Beard, C.A.; Buksa, J.J.; Davidson, J.W.; Sailor, W.C.; Williamson, M.A.

    1995-04-01

    In preparation for and in support of a detailed R and D Plan for the Accelerator-Based Conversion (ABC) of weapons plutonium, an ABC Plant Layout Study was conducted at the level of a pre-conceptual engineering design. The plant layout is based on an adaptation of the Molten-Salt Breeder Reactor (MSBR) detailed conceptual design that was completed in the early 1070s. Although the ABC Plant Layout Study included the Accelerator Equipment as an essential element, the engineering assessment focused primarily on the Target; Primary System (blanket and all systems containing plutonium-bearing fuel salt); the Heat-Removal System (secondary-coolant-salt and supercritical-steam systems); Chemical Processing; Operation and Maintenance; Containment and Safety; and Instrumentation and Control systems. Although constrained primarily to a reflection of an accelerator-driven (subcritical) variant of MSBR system, unique features and added flexibilities of the ABC suggest improved or alternative approaches to each of the above-listed subsystems; these, along with the key technical issues in need of resolution through a detailed R&D plan for ABC are described on the bases of the ``strawman`` or ``point-of-departure`` plant layout that resulted from this study.

  11. Background Intestinal 18F-FDG Uptake Is Related to Serum Lipid Profile and Obesity in Breast Cancer Patients

    PubMed Central

    Yoon, Hai-Jeon; Kim, Han-Na; Yun, Yeojun; Kim, Yemi; Ha, Ae-Na

    2015-01-01

    Background This study investigated the relationships between background intestinal uptake on 18F–FDG PET and cardio-metabolic risk (CMR) factors. Methods A total of 326 female patients that underwent 18F–FDG PET to determine the initial stage of breast cancer were enrolled. None of the patients had history of diabetes or hypertension. The background intestinal uptake on PET was visually graded (low vs. high uptake group) and quantitatively measured using the maximal standardized uptake value (SUVmax). SUVmax of 7 bowel segments (duodenum, jejunum, ileum, cecum, hepatic flexure, splenic flexure, and descending colon-sigmoid junction) were averaged for the total bowel (TB SUVmax). Age, body mass index (BMI), fasting blood glucose level (BST), triglyceride (TG), cholesterol, high density lipoprotein (HDL), and low density lipoprotein (LDL) were the considered CMR factors. The relationships between background intestinal 18F–FDG uptake on PET and diverse CMR factors were analyzed. Results The visual grades based on background intestinal 18F–FDG uptake classified 100 (30.7%) patients into the low uptake group, while 226 (69.3%) were classified into the high uptake group. Among CMR factors, age (p = 0.004), BMI (p<0.001), and TG (p<0.001) were significantly different according to visual grade of background intestinal 18F–FDG uptake. Quantitative TB SUVmax showed significant positive correlation with age (r = 0.203, p<0.001), BMI (r = 0.373, p<0.001), TG (r = 0.338, p<0.001), cholesterol (r = 0.148, p = 0.008), and LDL (r = 0.143, p = 0.024) and significant negative correlation with HDL (r = -0.147, p = 0.022). Multivariate analysis indicated that BMI and TG were independent factors in both visually graded background intestinal 18F–FDG uptake (p = 0.027 and p = 0.023, respectively) and quantitatively measured TB SUVmax (p = 0.006 and p = 0.004, respectively). Conclusion Increased background intestinal 18F–FDG uptake on PET may suggest alteration of lipid

  12. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  13. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  14. DarkLight radiation backgrounds

    SciTech Connect

    Kalantarians, Narbe

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-on, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW CW beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, field emission inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation.

  15. Characteristics of a veteran acrylic lens relative to acrylic lens materials after accelerated laboratory weathering

    NASA Astrophysics Data System (ADS)

    Miller, David C.; Arndt, Thomas; Kogler, René

    2015-09-01

    The durability of poly(methyl methacrylate) is examined using veteran lenses obtained from CPV modules fielded for 27 years in Phoenix. The lens facets were milled from the lens interior, followed by depth-specific toming to characterize variation at four depths through the thickness. Optical transmittance was measured using a spectrophotometer, both with and without an integrating sphere. Diffuse transmittance (the optical haze) and yellowness index were determined from the transmittance. Molecular weight was characterized using size exclusion chromatography, also in conjunction with the toming. The veteran lens material is compared to contemporary PMMA formulations, aged in an indoor chamber. The modest reductions in transmittance and molecular weight for the lenses were generally similar to those of the contemporary materials, suggesting an indoor accelerated aging test might be used; additional tests must, however, be applied to invoke the haze, uniquely observed for the lens specimen.

  16. Do US Black Women Experience Stress-Related Accelerated Biological Aging?

    PubMed Central

    Hicken, Margaret T.; Pearson, Jay A.; Seashols, Sarah J.; Brown, Kelly L.; Cruz, Tracey Dawson

    2010-01-01

    We hypothesize that black women experience accelerated biological aging in response to repeated or prolonged adaptation to subjective and objective stressors. Drawing on stress physiology and ethnographic, social science, and public health literature, we lay out the rationale for this hypothesis. We also perform a first population-based test of its plausibility, focusing on telomere length, a biomeasure of aging that may be shortened by stressors. Analyzing data from the Study of Women's Health Across the Nation (SWAN), we estimate that at ages 49–55, black women are 7.5 years biologically “older” than white women. Indicators of perceived stress and poverty account for 27% of this difference. Data limitations preclude assessing objective stressors and also result in imprecise estimates, limiting our ability to draw firm inferences. Further investigation of black-white differences in telomere length using large-population-based samples of broad age range and with detailed measures of environmental stressors is merited. PMID:20436780

  17. Rate-related accelerating (autodecremental) atrial pacing for reversion of paroxysmal supraventricular tachycardia.

    PubMed

    Nathan, A; Hellestrand, K; Ward, D; Spurrell, R; Camm, J

    1982-01-01

    Twenty consecutive patients with paroxysmal intra A-V nodal or atrio-ventricular tachycardia had a new tachycardia reversion pacing modality evaluated during routine electrophysiological study. The pacing was controlled by a micropressor interfaced with a stimulator connected to a right atrial pacing electrode. On detection of tachycardia the first pacing cycle interval is equal to the tachycardia cycle length minus a decrement value D. Each subsequent pacing cycle is further reduced by the same value of D, thus accelerating the pacing burst until a plateau of 100 beats/min faster than tachycardia (with an absolute lower limit of 275 beats/min) is reached. Seven different values of D (2, 4, 8, 16, 24, 34, 50 msec) were assessed in combination with three different durations of pacing P (500, 5000 msec). With P:500, only 2/20 tachycardias were terminated, but with P:1000, 16/20 were terminated. With P:5000 all were terminated and the combination successful in all patients was P:5000 and D:16. No unwanted arrhythmias were induced. In contrast, competitive constant rate overdrive atrial pacing accomplished tachycardia termination in all cases, but in four instances resulted in atrial flutter or fibrillation. Autodecremental pacing, which tends to avoid stimulation in the vulnerable period, allowed safe and successful termination of all tachycardias evaluated in this study. PMID:7069321

  18. Acoustic particle acceleration sensors

    SciTech Connect

    Franklin, J.B.; Barry, P.J.

    1996-04-01

    A crossed dipole array provides a directional receiving capability in a relatively small sensor package and is therefore very attractive for many applications in acoustics. Particle velocity measurements on two axes perpendicular to each other are required to provide the dipole signals. These can be obtained directly using particle velocity sensors or via simple transfer functions using acceleration and displacement sensors. Also, the derivative of the acoustic pressure with respect to space provides a signal proportional to the particle acceleration and gives rise to the pressure gradient sensor. Each of these sensors has strengths and drawbacks depending on the frequency regime of interest, the noise background, and whether a point or a line configuration of dipole sensors is desired. In this paper, the performance of acceleration sensors is addressed using a sensor concept developed at DREA. These sensors exploit bending stresses in a cantilever beam of piezoelectric material to obtain wide bandwidth and high sensitivity. Models which predict the acceleration sensitivity, pressure sensitivity, and natural frequency for this type of sensor are described. Experimental results obtained using several different versions of these sensors are presented and compared with theory. The predicted performance of acceleration sensors are compared with that of pressure gradient arrays and particle velocity sensors. {copyright} {ital 1996 American Institute of Physics.}

  19. Koppitz Bender Gestalt Scores in First-Grade Children as Related to Ethnocultural Background, Socioeconomic Class, and Sex Factors

    ERIC Educational Resources Information Center

    Zuelzer, Margot B.; And Others

    1976-01-01

    This study investigated whether Koppitz Bender Gestalt Scores were related to ethnocultural, socioeconomic and sex factors when statistical controls for intelligence were used. When intelligence was controlled for, it eliminated many effects for these variables. Results are discussed. (NG)

  20. The mass discrepancy acceleration relation in early-type galaxies: extended mass profiles and the phantom menace to MOND

    NASA Astrophysics Data System (ADS)

    Janz, Joachim; Cappellari, Michele; Romanowsky, Aaron J.; Ciotti, Luca; Alabi, Adebusola; Forbes, Duncan A.

    2016-09-01

    The dark matter (DM) haloes around spiral galaxies appear to conspire with their baryonic content: empirically, significant amounts of DM are inferred only below a universal characteristic acceleration scale. Moreover, the discrepancy between the baryonic and dynamical mass, which is usually interpreted as the presence of DM, follows a very tight mass discrepancy acceleration (MDA) relation. Its universality, and its tightness in spiral galaxies, poses a challenge for the DM interpretation and was used to argue in favour of MOdified Newtonian Dynamics (MOND). Here, we test whether or not this applies to early-type galaxies. We use the dynamical models of fast-rotator early-type galaxies by Cappellari et al. based on ATLAS3D and SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) data, which was the first homogenous study of this kind, reaching ˜4 Re, where DM begins to dominate the total mass budget. We find the early-type galaxies to follow an MDA relation similar to spiral galaxies, but systematically offset. Also, while the slopes of the mass density profiles inferred from galaxy dynamics show consistency with those expected from their stellar content assuming MOND, some profiles of individual galaxies show discrepancies.

  1. The Relative Influence of Childhood Sexual Abuse and Other Family Background Risk Factors on Adult Adversities in Female Outpatients Treated for Anxiety Disorders and Depression

    ERIC Educational Resources Information Center

    Peleikis, Dawn E.; Mykletun, Arnstein; Dahl, Alv A.

    2004-01-01

    Objective: This study from Norway examines the relative influence of child sexual abuse (CSA) and family background risk factors (FBRF) on the risk for current mental disorders and the quality of current intimate relationships in women with CSA treated for anxiety disorders and/or depression. Women with these disorders frequently seek treatment,…

  2. Relative Luminance and Figure-Background Segmentation Problems: Using AMLA to Avoid Nondiscernible Stimulus Pairs in Common and Color Blind Observers

    ERIC Educational Resources Information Center

    Jover, Julio Lillo; Moreira, Humberto

    2005-01-01

    Four experiments evaluated AMLA temporal version accuracy to measure relative luminosity in people with and without color blindness and, consequently, to provide the essential information to avoid poor figure-background combinations in any possible "specific screen-specific observer" pair. Experiment 1 showed that two very different apparatus, a…

  3. Child Physical Abuse and the Related PTSD in Taiwan: The Role of Chinese Cultural Background and Victims' Subjective Reactions

    ERIC Educational Resources Information Center

    Chou, Chia-Ying; Su, Yi-Jen; Wu, Ho-Mao; Chen, Sue-Huei

    2011-01-01

    Objective: This study aimed to investigate child physical abuse (CPA) while taking into account the more rigorous definitions of CPA in the Chinese societies. The prevalence of CPA and CPA-related PTSD were estimated, together with the examination of peri-traumatic subjective reactions and their impacts on PTSD. Methods: In a Taiwanese sample of…

  4. Implementing a hospital-based violence-related injury surveillance system--a background to the Jamaican experience.

    PubMed

    Ward, Elizabeth; Durant, Tonji; Thompson, Martie; Gordon, Georgiana; Mitchell, Wayne; Ashley, Deanna

    2002-12-01

    Violence, a leading cause of injuries and death, is recognized as a major public health problem. In 1996, injuries were the second leading cause of hospitalizations in Jamaica. The estimated annual cost of in-patient care for injuries was 11.6 million US dollars. To develop strategies to reduce the impact of violence-related injuries on Jamaican health care resources, the Ministry of Health, Division of Health Promotion and Protection (MOH/DHPP) in collaboration with the Centers for Disease Control and Prevention and the Tropical Metabolic Research Institute, University of the West Indies Mona, designed and implemented a violence-related injury surveillance system (VRISS) at Kingston Public Hospital (KPH). In 1998, the VRISS, based on the International Classification of External Cause of Injury (ICECI), was implemented in the accident and emergency (A&E) department of Jamaica's tertiary care hospital, KPH. VRISS collects demographic, method and circumstance of injury, victim-perpetrator relationship and patient's discharge status data. From 8/1/98 to 7/31/99, data on 6,107 injuries were collected. Injuries occurred primarily among males aged 25-44 years. Most injuries (54%; 3171) were caused by use of a sharp object. Nearly half (49%; 2992) were perpetrated by acquaintances. The majority, 70% (4,252), were the result of a fight or argument and 17% were admitted to the hospital. The VRISS utilized A&E department data to characterize violence-related injuries in Jamaica, a resource-limited environment. These data will be used to guide intervention development to reduce violence-related injuries in Jamaica. PMID:12613103

  5. [Experimental studies of the relative biological effectiveness of accelerated charged particles varying in energy].

    PubMed

    Fedorenko, B S; Petrov, V M; Smirnova, O A; Vorozhtsova, S V; Abrosimova, A N

    2006-01-01

    Experimental results and literary data were analyzed for the relative biological effectiveness of heavy charged particles in a broad range of energy and LET to cells of humans and other mammals in culture, whole body of laboratory animals, microorganisms, bacteriophages, and plants. Analyzed were data obtained with the use of a diversity of tests of acute and delayed lesions induced by ionizing radiation, cancers and cataracts, specifically. Non-parametric methods are applied in parallel to the classic method of calculating the coefficients of relative biological effectiveness by correlating the equal-effective doses of the standard and a given radiation. Consideration is given to factors that may modify RBE values estimated for different types of radiation. PMID:17193971

  6. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M.; Vrsnak, B.

    2012-08-10

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  7. Regulation of nucleic acid and protein synthesis: a background study related to the biological effects of radiation. Progress report

    SciTech Connect

    Zamecnik, P.

    1984-01-01

    Progress is reported in the following areas in defining the varied roles of diadenosine 5', 5'''-P/sup 1/, P/sup 4/-tetraphosphate (Ap/sub 4/A) in metabolic events within the living cell: (1) Ap/sub 4/A association with a subunit of DNA polymerase ..cap alpha..; (2) studies on the unusual ordered structure of Ap/sub 4/A and of related bisnucleoside oligophosphates; (3) the utilization of technetium labeled Ap/sub 4/A as a radionuclide diagnostic reagent; and (4) the role of Ap/sub 4/A in the blood clotting mechanism. (ACR)

  8. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  9. Sun-related behaviours among young Australians with Asian ethnic background: differences according to sociocultural norms and skin tone perceptions.

    PubMed

    Day, A K; Wilson, C J; Hutchinson, A D; Roberts, R M

    2015-07-01

    Deliberate tanning, poor sun protection and sun exposure increase an individual's risk for skin cancer. Recent evidence suggests that individuals of Asian heritage have lower incidence of skin cancer than Caucasians but that their post-diagnosis outcomes are often worse. In Western cultures tanning behaviours are often motivated by a desire for 'attractive' tanned skin. Conversely, a light complexion is desired in a number of Asian cultures and may consequently serve to protect this group from excessive and risky sun exposure behaviours. This possibility is yet to be tested, with little known about the sun-related behaviours of Asian people residing in Australia. The present study involves 140 South Australian young adults who report having Asian heritage. Results show that the majority of female participants, and significantly fewer males, reported participating in deliberate outdoor tanning behaviour. Perceptions of family, peer and media tanning norms influenced behaviour, with peer norms being the strongest predictor. The desire for a lighter skin tone was associated with increased sun-protective behaviour and a lower number of previous severe sunburns. As a significant proportion of participants engaged in deliberate tanning behaviour, it is recommended that future research continue to explore factors associated with tanning, including an explicit measure of culture. PMID:25546634

  10. Inflammatory insult during pregnancy accelerates age-related behavioral and neurobiochemical changes in CD-1 mice.

    PubMed

    Li, Xue-Yan; Wang, Fang; Chen, Gui-Hai; Li, Xue-Wei; Yang, Qi-Gang; Cao, Lei; Yan, Wen-Wen

    2016-06-01

    Data shows that inflammation during pregnancy significantly exerts a long-term influence on offspring, such as increasing the risk of adult cognition decline in animals. However, it is unclear whether gestational inflammation affects the neurobehavioral and neurobiochemical outcomes in the mother-self during aging. In this study, pregnant CD-1 mice intraperitoneally received lipopolysaccharide (LPS) in two doses (25 and 50 g/kg, respectively) or normal saline daily during gestational days 15-17. At the age of 15 months, a battery of behavioral tasks was employed to evaluate their species-typical behaviors, sensorimotor ability, anxiety levels, and spatial learning and memory abilities. An immunohistochemical method was utilized preliminarily to detect neurobiochemical indicators consisting of amyloid-β, phosphorylated tau, presynaptic proteins synaptotagmin-1 and syntaxin-1, glial fibrillary acidic protein (GFAP), and histone-4 acetylation on the K8 site (H4K8ac). The behavioral results showed that LPS exposure during pregnancy exacerbated a decline in 15-month-old CD-1 mice's abilities to nest, their sensorimotor and spatial learning and memory capabilities, and increased their anxiety levels. The neurobiochemical results indicated that gestational LPS exposure also intensified age-related hippocampal changes, including increased amyloid-β42, phosphorylated tau, synaptotagmin-1 and GFAP, and decreased syntaxin-1 and H4K8ac. Our results suggested that the inflammatory insult during pregnancy could be an important risk factor for the development of Alzheimer's disease, and the H4K8 acetylation might play an important role in the underlying mechanism. This study offers a perspective for improving strategies that support healthy development and successful aging. PMID:27194408

  11. Quasi two day wave-related variability in the background dynamics and composition of the mesosphere/thermosphere and the ionosphere

    PubMed Central

    Chang, Loren C; Yue, Jia; Wang, Wenbin; Wu, Qian; Meier, R R

    2014-01-01

    Dissipating planetary waves in the mesosphere/lower thermosphere (MLT) region may cause changes in the background dynamics of that region, subsequently driving variability throughout the broader thermosphere/ionosphere system via mixing due to the induced circulation changes. We report the results of case studies examining the possibility of such coupling during the northern winter in the context of the quasi two day wave (QTDW)—a planetary wave that recurrently grows to large amplitudes from the summer MLT during the postsolstice period. Six distinct QTDW events between 2003 and 2011 are identified in the MLT using Sounding of the Atmosphere using Broadband Emission Radiometry temperature observations. Concurrent changes to the background zonal winds, zonal mean column O/N2 density ratio, and ionospheric total electron content (TEC) are examined using data sets from Thermosphere Ionosphere Mesosphere Energetics and Dynamics Doppler Interferometer, Global Ultraviolet Imager, and Global Ionospheric Maps, respectively. We find that in the 5–10 days following a QTDW event, the background zonal winds in the MLT show patterns of eastward and westward anomalies in the low and middle latitudes consistent with past modeling studies on QTDW-induced mean wind forcing, both below and at turbopause altitudes. This is accompanied by potentially related decreases in zonal mean thermospheric column O/N2, as well as to low-latitude TECs. The recurrent nature of the above changes during the six QTDW events examined point to an avenue for vertical coupling via background dynamics and chemistry of the thermosphere/ionosphere not previously observed. Key Points Dissipating planetary waves (PWs) in the MLT can drive background wind changes Mixing from dissipating PWs drive thermosphere/ionosphere composition changes First observations of QTDW-driven variability from this mechanism PMID:26312201

  12. Age-related trends in gene expression in the chemosensory-nasal mucosae of senescence-accelerated mice.

    PubMed

    Getchell, Thomas V; Peng, Xuejun; Stromberg, Arnold J; Chen, Kuey-Chu; Paul Green, C; Subhedar, Nishikant K; Shah, Dharmen S; Mattson, Mark P; Getchell, Marilyn L

    2003-04-01

    We have utilized high-density GeneChip oligonucleotide arrays to investigate the use of the senescence-accelerated mouse (SAM) as a biogerontological resource to identify patterns of gene expression in the chemosensory-nasal mucosa. Gene profiling in chronologically young and old mice of the senescence-resistant (SAMR) and senescence-prone (SAMP) strains revealed 133 known genes that were modulated by a three-fold or greater change either in one strain or the other or in both strains during aging. We also identified known genes in our study which based on their encoded proteins were identified as aging-related genes in the aging neocortex and cerebellum of mice as reported by Lee et al. (2000) [Nat. Genet. 25 (2000) 294]. Changes in gene profiles for chemosensory-related genes including olfactory and vomeronasal receptors, sensory transduction-associated proteins, and odor and pheromone transport molecules in the young SAMR and SAMP were compared with age-matched C57BL/6J mice. An analysis of known gene expression profiles suggests that changes in the expression of immune factor genes and genes associated with cell cycle progression and cell death were particularly prominent in the old SAM strains. A preliminary cellular validation study supported the dysregulation of cell cycle-related genes in the old SAM strains. The results of our initial study indicated that the use of the SAM models of aging could provide substantive information leading to a more fundamental understanding of the aging process in the chemosensory-nasal mucosa at the genomic, molecular, and cellular levels. PMID:12605961

  13. Accelerated Testing and Modeling of Potential-Induced Degradation as a Function of Temperature and Relative Humidity

    SciTech Connect

    Hacke, Peter; Spataru, Sergiu; Terwilliger, Kent; Perrin, Greg; Glick, Stephen; Kurtz, Sarah; Wohlgemuth, John

    2015-06-14

    An acceleration model based on the Peck equation was applied to power performance of crystalline silicon cell modules as a function of time and of temperature and humidity, the two main environmental stress factors that promote potential-induced degradation. This model was derived from module power degradation data obtained semi-continuously and statistically by in-situ dark current-voltage measurements in an environmental chamber. The modeling enables prediction of degradation rates and times as functions of temperature and humidity. Power degradation could be modeled linearly as a function of time to the second power; additionally, we found that coulombs transferred from the active cell circuit to ground during the stress test is approximately linear with time. Therefore, the power loss could be linearized as a function of coulombs squared. With this result, we observed that when the module face was completely grounded with a condensed phase conductor, leakage current exceeded the anticipated corresponding degradation rate relative to the other tests performed in damp heat.

  14. Some folded issues related to over-shielded and unplanned rooms for medical linear accelerators - A case study

    NASA Astrophysics Data System (ADS)

    Muhammad, Wazir; Ullah, Asad; Hussain, Amjad; Ali, Nawab; Alam, Khan; Khan, Gulzar; Matiullah; Maeng, Seongjin; Lee, Sang Hoon

    2015-08-01

    A medical linear accelerator (LINAC) room must be properly shielded to limit the outside radiation exposure to an acceptable safe level defined by individual state and international regulations. However, along with this prime objective, some additional issues are also important. The current case-study was designed to unfold the issues related to over-shielded and unplanned treatment rooms for LINACs. In this connection, an apparently unplanned and over-shielded treatment room of 610 × 610 cm2 in size was compared with a properly designed treatment room of 762 × 762 cm2 in size ( i.e., by following the procedures and recommendations of the IAEA Safety Reports Series No. 47 and NCRP 151). Evaluation of the unplanned room indicated that it was over-shielded and that its size was not suitable for total body irradiation (TBI), although the license for such a treatment facility had been acquired for the installed machine. An overall 14.96% reduction in the total shielding volume ( i.e., concrete) for an optimally planned room as compared to a non-planned room was estimated. Furthermore, the inner room's dimensions were increased by 25%, in order to accommodate TBI patients. These results show that planning and design of the treatment rooms are imperative to avoid extra financial burden to the hospitals and to provide enough space for easy and safe handling of the patients. A spacious room is ideal for storing treatment accessories and facilitates TBI treatment.

  15. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  16. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  17. Space Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This training video, presented by the Lewis Research Center's Space Experiments Division, gives a background and detailed instructions for preparing the space acceleration measurement system (SAMS) for use. The SAMS measures, conditions, and records forces of low gravity accelerations, and is used to determine the effect of these forces on various experiments performed in microgravity. Inertial sensors are used to measure positive and negative acceleration over a specified frequency range. The video documents the SAMS' uses in different configurations during shuttle missions.

  18. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  19. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  20. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  1. Ion engine endurance testing at high background pressures

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Pless, Lewis C.; Garner, Charles E.

    1992-01-01

    Ion engine endurance testing at vacuum chamber pressures in the low 10 exp -3 Pa range is enabled through the use of a three-grid accelerator system with the decelerator grid biased 50 to 100 volts negative of neutralizer cathode potential. The negative decelerator grid serves to collect the facility induced charge exchange ion current which normally results in rapid erosion of the accelerator grid during testing at elevated vacuum chamber pressures. This screen, accelerator, negative decelerator (SAND) grid configuration enables an order of magnitude reduction in vacuum chamber pumping speeds relative to that required for endurance testing of ion engines with conventional two-grid accelerator systems. A 900-hr test of a 30-cm diameter engine at 6.5 kW and a tank pressure of 3.7 x 10 exp -3 Pa was performed to test the feasibility of the three-grid SAND accelerator system technology. Grid erosion rates from this test are compared to those from a 200-hr test performed with the same discharge chamber, in the same test facility, and at the same background pressure with a conventional two grid accelerator system. The SAND optics resulted in greater than a factor of 100 reduction in accelerator grid erosion rate relative to the two-grid system.

  2. Ion engine endurance testing at high background pressures

    NASA Astrophysics Data System (ADS)

    Brophy, John R.; Pless, Lewis C.; Garner, Charles E.

    1992-07-01

    Ion engine endurance testing at vacuum chamber pressures in the low 10 exp -3 Pa range is enabled through the use of a three-grid accelerator system with the decelerator grid biased 50 to 100 volts negative of neutralizer cathode potential. The negative decelerator grid serves to collect the facility induced charge exchange ion current which normally results in rapid erosion of the accelerator grid during testing at elevated vacuum chamber pressures. This screen, accelerator, negative decelerator (SAND) grid configuration enables an order of magnitude reduction in vacuum chamber pumping speeds relative to that required for endurance testing of ion engines with conventional two-grid accelerator systems. A 900-hr test of a 30-cm diameter engine at 6.5 kW and a tank pressure of 3.7 x 10 exp -3 Pa was performed to test the feasibility of the three-grid SAND accelerator system technology. Grid erosion rates from this test are compared to those from a 200-hr test performed with the same discharge chamber, in the same test facility, and at the same background pressure with a conventional two grid accelerator system. The SAND optics resulted in greater than a factor of 100 reduction in accelerator grid erosion rate relative to the two-grid system.

  3. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  4. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  5. Ion acceleration from thin foil and extended plasma targets by slow electromagnetic wave and related ion-ion beam instability

    SciTech Connect

    Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Pegoraro, F.; Bulanov, S. S.; Geddes, C. G. R.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2012-10-15

    When ions are accelerated by the radiation pressure of a laser pulse, their velocity cannot exceed the pulse group velocity which can be considerably smaller than the speed of light in vacuum. This is demonstrated in two cases corresponding to a thin foil target irradiated by high intensity laser light and to the hole boring produced in an extended plasma by the laser pulse. It is found that the beams of accelerated ions are unstable against Buneman-like and Weibel-like instabilities which results in the broadening of the ion energy spectrum.

  6. Computing Principal Eigenvectors of Large Web Graphs: Algorithms and Accelerations Related to PageRank and HITS

    ERIC Educational Resources Information Center

    Nagasinghe, Iranga

    2010-01-01

    This thesis investigates and develops a few acceleration techniques for the search engine algorithms used in PageRank and HITS computations. PageRank and HITS methods are two highly successful applications of modern Linear Algebra in computer science and engineering. They constitute the essential technologies accounted for the immense growth and…

  7. [Relative biological effectiveness of accelerated heavy ions and fast neutrons estimated from frequency of aberration mytoses in the retinal epithelium].

    PubMed

    Vorozhtsova, S V; Shafirkin, A V; Fedorenko, B S

    2006-01-01

    Analyzed was the literature and authors' experimental data concerning lesion and recovery of epithelium cells of mice retina immediately and long after irradiation at different sources including single and partly fractionated irradiation by gamma- and X-rays, accelerated protons, helium, carbon and boron ions, and fast neutrons of the reactor range in a large spectrum of doses and LET. Reviewed are some new techniques of determining the RBE coefficient for these types of radiation; large values of the RBE coefficients for accelerated ions and neutrons (5-10 times higher than RBE coefficients calculated for the next day following irradiation) are a result of integration into calculation of the available data about the delayed disorders in retinal epithelium cell regeneration. PMID:17193969

  8. Glutamate Cysteine Ligase Modifier Subunit (Gclm) Null Mice Have Increased Ovarian Oxidative Stress and Accelerated Age-Related Ovarian Failure.

    PubMed

    Lim, Jinhwan; Nakamura, Brooke N; Mohar, Isaac; Kavanagh, Terrance J; Luderer, Ulrike

    2015-09-01

    Glutathione (GSH) is the one of the most abundant intracellular antioxidants. Mice lacking the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH. Our prior work showed that GSH plays antiapoptotic roles in ovarian follicles. We hypothesized that Gclm(-/-) mice have accelerated ovarian aging due to ovarian oxidative stress. We found significantly decreased ovarian GSH concentrations and oxidized GSH/oxidized glutathione redox potential in Gclm(-/-) vs Gclm(+/+) ovaries. Prepubertal Gclm(-/-) and Gclm(+/+) mice had similar numbers of ovarian follicles, and as expected, the total number of ovarian follicles declined with age in both genotypes. However, the rate of decline in follicles was significantly more rapid in Gclm(-/-) mice, and this was driven by accelerated declines in primordial follicles, which constitute the ovarian reserve. We found significantly increased 4-hydroxynonenal immunostaining (oxidative lipid damage marker) and significantly increased nitrotyrosine immunostaining (oxidative protein damage marker) in prepubertal and adult Gclm(-/-) ovaries compared with controls. The percentage of small ovarian follicles with increased granulosa cell proliferation was significantly higher in prepubertal and 2-month-old Gclm(-/-) vs Gclm(+/+) ovaries, indicating accelerated recruitment of primordial follicles into the growing pool. The percentages of growing follicles with apoptotic granulosa cells were increased in young adult ovaries. Our results demonstrate increased ovarian oxidative stress and oxidative damage in young Gclm(-/-) mice, associated with an accelerated decline in ovarian follicles that appears to be mediated by increased recruitment of follicles into the growing pool, followed by apoptosis at later stages of follicular development. PMID:26083875

  9. Paraelectric gas flow accelerator

    NASA Technical Reports Server (NTRS)

    Sherman, Daniel M. (Inventor); Wilkinson, Stephen P. (Inventor); Roth, J. Reece (Inventor)

    2001-01-01

    A substrate is configured with first and second sets of electrodes, where the second set of electrodes is positioned asymmetrically between the first set of electrodes. When a RF voltage is applied to the electrodes sufficient to generate a discharge plasma (e.g., a one-atmosphere uniform glow discharge plasma) in the gas adjacent to the substrate, the asymmetry in the electrode configuration results in force being applied to the active species in the plasma and in turn to the neutral background gas. Depending on the relative orientation of the electrodes to the gas, the present invention can be used to accelerate or decelerate the gas. The present invention has many potential applications, including increasing or decreasing aerodynamic drag or turbulence, and controlling the flow of active and/or neutral species for such uses as flow separation, altering heat flow, plasma cleaning, sterilization, deposition, etching, or alteration in wettability, printability, and/or adhesion.

  10. Plasma accelerators

    SciTech Connect

    Ruth, R.D.; Chen, P.

    1986-03-01

    In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

  11. Effects of deoxynivalenol (DON), zearalenone (ZEN), and related metabolites on equine peripheral blood mononuclear cells (PBMC) in vitro and background occurrence of these toxins in horses.

    PubMed

    Schumann, Barbara; Winkler, Janine; Mickenautsch, Nicola; Warnken, Tobias; Dänicke, Sven

    2016-08-01

    Both deoxynivalenol (DON), zearalenone (ZEN), and their metabolites are known to modulate immune cells in various species whereby viability and proliferation are influenced. Such effects were rarely examined in horses. Therefore, one aim of the present study was to titrate the inhibitory concentrations of DON, 3-acetyl-DON (3AcDON), de-epoxy-DON (DOM-1), ZEN, and α- and β-zearalenol (ZEL) at which viability and proliferation of equine PBMC were reduced by 50 % (IC50) and 10 % (IC10) in vitro. For evaluation of practical relevance of the in vitro findings, a further aim was to screen horses for the background occurrence of DON, ZEN, and their metabolites in systemic circulation and to relate toxin residues both to the inhibitory toxin concentrations and to hematological and clinical-chemical characteristics.The IC50 (μM) for DON, 3AcDON, β-ZEL, α-ZEL, and ZEN were determined at 3.09, 25.90, 75.44, 97.44, and 98.15 in unstimulated cells, respectively, while in proliferating cells, the corresponding IC50 values were 0.73, 6.89, 45.16, 75.96, and 82.51. Neither viability nor proliferation was influenced by DOM-1 up to a concentration of 100 μM.The in vivo screening (N = 49) revealed the occurrence of ZEN (N = 24), α-ZEL (N = 3), β-ZEL (N = 37), DON, and DOM-1 (N = 2). The detected concentrations were much lower than the corresponding IC50 while the IC10 of DON and β-ZEL for proliferating PBMC corresponded to approximately 26 and 35 ng/mL which might be relevant when contaminated diets are fed.Clinical-chemical and hematological traits were not related to mycotoxin residue levels excepting blood urea nitrogen which was positively correlated to the sum of β-ZEL, α-ZEL, and ZEN concentration. Whether this reflects simply the feeding history of the horses or renal failures giving rise to a prolonged half-life of the toxins needs to be clarified further. PMID:27255919

  12. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  13. Attention's Accelerator.

    PubMed

    Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

    2016-06-01

    How do people get attention to operate at peak efficiency in high-pressure situations? We tested the hypothesis that the general mechanism that allows this is the maintenance of multiple target representations in working and long-term memory. We recorded subjects' event-related potentials (ERPs) indexing the working memory and long-term memory representations used to control attention while performing visual search. We found that subjects used both types of memories to control attention when they performed the visual search task with a large reward at stake, or when they were cued to respond as fast as possible. However, under normal circumstances, one type of target memory was sufficient for slower task performance. The use of multiple types of memory representations appears to provide converging top-down control of attention, allowing people to step on the attentional accelerator in a variety of high-pressure situations. PMID:27056975

  14. A Quasi-Experimental Study into the Relations between Families' Social and Cultural Background and Children's Creche Experience and Global Cognitive Competence in Primary School

    ERIC Educational Resources Information Center

    Burger, Kaspar

    2012-01-01

    This study analysed the role of both sociocultural background and exposure to a creche on children's development of cognitive competence in Switzerland. Data were derived from a survey on children's cognitive proficiency after enrolment to primary school. Correlations and multiple linear regressions indicate that creche experience was not related…

  15. Differences in the Neural Mechanisms of Selective Attention in Children from Different Socioeconomic Backgrounds: An Event-Related Brain Potential Study

    ERIC Educational Resources Information Center

    Stevens, Courtney; Lauinger, Brittni; Neville, Helen

    2009-01-01

    Previous research indicates that children from lower socioeconomic backgrounds show deficits in aspects of attention, including a reduced ability to filter irrelevant information and to suppress prepotent responses. However, less is known about the neural mechanisms of group differences in attention, which could reveal the stages of processing at…

  16. 'Palliative care': a contradiction in terms? A qualitative study of cancer patients with a Turkish or Moroccan background, their relatives and care providers

    PubMed Central

    2010-01-01

    Background Palliative cancer care aims to improve quality of life and ultimately quality of dying, while prolonging life is not an objective anymore when death nears. The question is, however, whether these perspectives on palliative care are congruent with the perspectives of immigrant families with a Turkish or Moroccan background. Methods A qualitative design was used as we were looking for the personal views of 'very ill' cancer patients with a Turkish or Moroccan background, their family members and their Dutch care providers. We interviewed 83 people, involved in 33 cases to obtain information about their views, values and norms on 'good care'. Results The main concerns about 'good care' expressed by Turkish and Moroccan families were: maximum treatment and curative care until the end of their lives, never having hope taken away, devoted care by their families, avoiding shameful situations, dying with a clear mind and being buried in their own country. Their views conflict, to some extent, with the dominant principles in palliative care, for example, the emphasis on quality of life and advanced care planning, which includes discussing diagnosis and prognosis with the patient. Conclusions Patients and their families with a Turkish or Moroccan background often have different ideas about 'good care' than their Dutch care providers. As many of them are aiming at cure until the end of life, they find 'good palliative care' a contradiction in terms. PMID:20831777

  17. Acceleration of Lung Regeneration by Platelet-Rich Plasma Extract through the Low-Density Lipoprotein Receptor-Related Protein 5-Tie2 Pathway.

    PubMed

    Mammoto, Tadanori; Chen, Zhao; Jiang, Amanda; Jiang, Elisabeth; Ingber, Donald E; Mammoto, Akiko

    2016-01-01

    Angiogenesis, the growth of new blood vessels, plays a key role in organ development, homeostasis, and regeneration. The cooperation of multiple angiogenic factors, rather than a single factor, is required for physiological angiogenesis. Recently, we have reported that soluble platelet-rich plasma (PRP) extract, which contains abundant angiopoietin-1 and multiple other angiogenic factors, stimulates angiogenesis and maintains vascular integrity in vitro and in vivo. In this report, we have demonstrated that mouse PRP extract increases phosphorylation levels of the Wnt coreceptor low-density lipoprotein receptor-related protein 5 (LRP5) and thereby activates angiogenic factor receptor Tie2 in endothelial cells (ECs) and accelerates EC sprouting and lung epithelial cell budding in vitro. PRP extract also increases phosphorylation levels of Tie2 in the mouse lungs and accelerates compensatory lung growth and recovery of exercise capacity after unilateral pneumonectomy in mice, whereas soluble Tie2 receptor or Lrp5 knockdown attenuates the effects of PRP extract. Because human PRP extract is generated from autologous peripheral blood and can be stored at -80°C, our findings may lead to the development of novel therapeutic interventions for various angiogenesis-related lung diseases and to the improvement of strategies for lung regeneration. PMID:26091161

  18. A Fundamental Theorem on Particle Acceleration

    SciTech Connect

    Xie, Ming

    2003-05-01

    A fundamental theorem on particle acceleration is derived from the reciprocity principle of electromagnetism and a rigorous proof of the theorem is presented. The theorem establishes a relation between acceleration and radiation, which is particularly useful for insightful understanding of and practical calculation about the first order acceleration in which energy gain of the accelerated particle is linearly proportional to the accelerating field.

  19. Accelerating Decoding-Related Skills in Poor Readers Learning a Foreign Language: A Computer-Based Intervention

    ERIC Educational Resources Information Center

    Björn, Piia Maria; Leppänen, Paavo H. T.

    2013-01-01

    The results of Fast ForWord® training on English decoding-related skills were examined. Finnish fifth-grade students were identified as having reading fluency problems and poor skills in English as a foreign language learned at school and were randomly assigned to either a training group (TRG) or a control group. The TRG ("n"?=?13)…

  20. Variations of the relative abundances of He, (C,N,O) and Fe-group nuclei in solar cosmic rays and their relationship to solar particle acceleration

    NASA Technical Reports Server (NTRS)

    Bertsch, D. L.; Biswas, S.; Fichtel, C. E.; Pellerin, C. J.; Reames, D. V.

    1973-01-01

    Measurements of the flux of helium nuclei in the 24 January 1971 event and of helium and (C,N,O) nuclei in the 1 September 1971 event are combined with previous measurements to obtain the relative abundances of helium, (C,N,O), and Fe-group nuclei in these events. These data are then summarized together with previously reported results to show that, even when the same detector system using a dE/dx plus range technique is used, differences in the He/(C,N,O) value in the same energy/nucleon interval are observed in solar cosmic ray events. Further, when the He/(C,N,O) value is lower the He/(Fe-group nuclei) value is also systematically lower in these large events. When solar particle acceleration theory is analyzed, it is seen that the results suggest that, for large events, Coulomb energy loss probably does not play a major role in determining solar particle composition at higher energies (10 MeV). The variations in multicharged nuclei composition are more likely due to partial ionization during the acceleration phase.

  1. Low-Frequency Wave Activity Detected by MMS during Dusk Magnetopause Crossings and its Relation to Heating and Acceleration of Particles

    NASA Astrophysics Data System (ADS)

    Le Contel, O.; Roux, A.; Retino, A.; Mirioni, L.; Sahraoui, F.; Chust, T.; Berthomier, M.; Chasapis, A.; Aunai, N.; Leroy, P.; Alison, D.; Lavraud, B.; Lindqvist, P. A.; Khotyaintsev, Y. V.; Vaivads, A.; Marklund, G. T.; Burch, J. L.; Torbert, R. B.; Moore, T.; Ergun, R. E.; Needell, J.; Chutter, M.; Rau, D.; Dors, I.; Macri, J.; Russell, C. T.; Magnes, W.; Strangeway, R. J.; Bromund, K. R.; Plaschke, F.; Fischer, D.; Leinweber, H. K.; Anderson, B. J.; Nakamura, R.; Argall, M. R.; Le, G.; Slavin, J. A.; Kepko, L.; Baumjohann, W.; Pollock, C. J.; Mauk, B.; Fuselier, S. A.; Goodrich, K.; Wilder, F. D.

    2015-12-01

    Since the 9th of July, the MMS fleet of four satellites have evolved into a tetrahedral configuration with an average inter-satellite distance of 160 km and an apogee of 12 earth radii on the dusk side. In this study we report on ultra-low (1 mHz to ~10 Hz) and very-low (10 Hz to ~ 4 kHz) frequency wave activity measured by the four satellites during several crossings of the dusk equatorial magnetopause. Since the Larmor radius of magnetosheath protons is of the order of 50 km, this inter-satellite distance allows us to investigate in detail the physics of the magnetopause at proton scales including current structures related to Kelvin-Helmholtz instability as well as other energy transfer processes. From wave polarization analysis, we characterize the different types of emissions and discuss different mechanisms of heating and acceleration of particles. In particular, we focus on the electron heating by kinetic Alfvén waves and lower hybrid waves and the electron acceleration by oblique whistler mode waves, which have been suggested as possible mechanisms from previous Cluster and THEMIS measurements.

  2. Accelerated relative sea-level rise and rapid coastal erosion: Testing a causal relationship for the Louisiana barrier islands

    USGS Publications Warehouse

    List, J.H.; Sallenger, A.H., Jr.; Hansen, M.E.; Jaffe, B.E.

    1997-01-01

    The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline west of the Mississippi delta are derived from bathymetric surveys conducted during the 1880s. 1930s and 1980s. An RMS difference criterion is employed to test whether an equilibrium profile form is maintained between survey years. Only about half the studied profiles meet the equilibrium Criterion this represents a significant limitation on the potential applicability of the Bruun rule. The profiles meeting the equilibrium criterion, along with measured rates of relative sea-level rise, are used to hindcast shoreline retreat rates at 37 locations within the study area. Modeled and observed shoreline retreat rates show no significant correlation. Thus in terms of the Bruun approach relative sea-level rise has no power for hindcasting (and presumably forecasting) rates of coastal erosion for the Louisiana barrier islands.

  3. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  4. Drug-Related Disorders and the Criminal and Clinical Background of the Prison Population of São Paulo State, Brazil

    PubMed Central

    dos Santos, Maíra Mendes; Quintana, Maria Ines; Moreira, Fernanda Gonçalves; Taborda, José Geraldo Vernet; Mari, Jair de Jesus; Andreoli, Sérgio Baxter

    2014-01-01

    Objective To analyze the association between drug (DAD) and alcohol (AAD) abuse and dependency and criminal and clinical background by gender of prisoners in São Paulo, Brazil. Method Cross-sectional study, random sample stratified by administrative district, from which prisons and prisoners were selected via random, multistage sampling. Psychiatric diagnoses were made with the CIDI 2.1. Lifetime prevalence and 95% CI were calculated and adjusted via analysis of complex samples. Multinomial logistic regression analysis was carried out with four categories of dependent variables: presence AAD; presence DAD; presence of another mental disorder; no mental disorders. For female alcohol and drug abuse and dependency (ADAD) were combined into a single category. Results The sample was composed by 1809 interviewed prisoners (1192 men and 617 women). Prevalence of DAD and AAD was 25.2% and 15.6%, respectively, among female prisoners, and 26.5% and 18.5% among males. Male prisoners with DAD were more likely to have a criminal record as an adolescent (OR 2.17), to be a repeat offender (OR 2.85), and to have committed a property crime (OR 2.18). Prisoners with AAD were repeat offenders (OR 2.18). Among female prisoners, ADAD was associated with repeat offenses (OR 3.39), a criminal record as an adolescent (OR 9.24), a clinical or infectious condition (OR 5.09), another health problem (OR 3.04), and violent crime (OR 2.5). Conclusion The study confirmed an association between drug-use disorders and the criminal and clinical background in the study population. Prisoners with such disorders were more likely to be repeat offenders and to have a criminal record as adolescents. Among female prisoners disorders were also associated with violent crime and health problems, while among males they were associated with property crime. These patterns in clinical and criminal backgrounds illustrate the need for social rehabilitation programs and specific medical treatment for prison

  5. Accelerated Reader.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Accelerated Reader, a system of computerized testing and record-keeping that supplements the regular classroom reading program. Accelerated Reader's primary goal is to increase literature-based reading practice. The program offers a computer-aided reading comprehension and management program intended to motivate…

  6. Progress on laser plasma accelerators

    SciTech Connect

    Chen, P.

    1986-04-01

    Several laser plasma accelerator schemes are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA). Theory indicates that a very high acceleration gradient, of order 1 GeV/m, can exist in the plasma wave driven by the beating lasers. Experimental results obtained on the PBWA experiment at UCLA confirms this. Parameters related to the PBWA as an accelerator system are derived, among them issues concerning the efficiency and the laser power and energy requirements are discussed.

  7. Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

    SciTech Connect

    Mark, J.W.K.

    1982-03-22

    Calculations suggest that experiments relating to disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics. In this regard, the low beam emittance of suggested multi-beam designs are very useful. Possibly even higher focal spot brightness could be obtained by plasma lenses which involve external fields on the beam which is stripped to a higher charge state by passing through a plasma cell. Preliminary results suggest that intensities approx. 10/sup 13/ - 10/sup 14/ W/cm/sup 2/ are achievable. Given these intensities, deposition experiments with heating of disks to greater than a million degrees Kelvin (100 eV) are expected.

  8. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  9. KEK digital accelerator

    NASA Astrophysics Data System (ADS)

    Iwashita, T.; Adachi, T.; Takayama, K.; Leo, K. W.; Arai, T.; Arakida, Y.; Hashimoto, M.; Kadokura, E.; Kawai, M.; Kawakubo, T.; Kubo, Tomio; Koyama, K.; Nakanishi, H.; Okazaki, K.; Okamura, K.; Someya, H.; Takagi, A.; Tokuchi, A.; Wake, M.

    2011-07-01

    The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA) is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR) ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  10. Using Current Data to Define New Approach in Age Related Macular Degeneration: Need to Accelerate Translational Research

    PubMed Central

    Anand, Akshay; Sharma, Kaushal; Chen, Wei; Sharma, Neel Kamal

    2014-01-01

    Age related macular degeneration (AMD) is one of the major retinal degenerative disease of ageing whose complex genetic basis remains undeciphered. The involvement of various other factors like mitochondrial genes, cytoskeletal proteins and the role of epigenetics has been described in this review. Several population based AMD genetic studies have been carried out worldwide. Despite the increased publication of reports, clinical translation still eludes this davastating disease. We suggest models to address roadblocks in clinical translation hoping that these would be beneficial to drive AMD research towards innovative biomarkers and therapeutics Therefore, addressing the need large autopsy studies and combining it with efficient use of bioinformatic tools, statistical modeling and probing SNP-biomarker association are key to time bound resolution of this disease. PMID:25132797

  11. Growth in Adolescent Delinquency and Alcohol Use in Relation to Young Adult Crime, Alcohol Use Disorders, and Risky Sex: A Comparison of Youth from Low- versus Middle-Income Backgrounds

    ERIC Educational Resources Information Center

    Mason, W. Alex; Hitch, Julia E.; Kosterman, Rick; McCarty, Carolyn A.; Herrenkohl, Todd I.; Hawkins, J. David

    2010-01-01

    Background: This study examined adolescent delinquency and alcohol use in relation to young adult crime, alcohol use disorders (AUDs), and risky sex. Analyses further examined the influences of late childhood involvement in these problem behavior outcomes, with mediation through teen delinquency and alcohol use, and examined differences in the…

  12. Elemental composition and radical formation potency of PM10 at an urban background station in Germany in relation to origin of air masses

    NASA Astrophysics Data System (ADS)

    Hellack, Bryan; Quass, Ulrich; Beuck, Henning; Wick, Gabriele; Kuttler, Wilhelm; Schins, Roel P. F.; Kuhlbusch, Thomas A. J.

    2015-03-01

    At an urban background station in Mülheim-Styrum, North Rhine Westphalia, Germany, a set of 75 PM10 samples was collected over a one year period, followed by analyses for mass, chemical composition and hydroxyl radical (OHrad) formation potency. Additionally, the origin of air masses for the sampling days was calculated by 48-h backward trajectories, subdivided into the four cardinal sectors. Significant lower PM10 mass concentrations were observed for summertime air masses from the west compared to the other seasons and cardinal sectors. For the OHrad formation potency higher values were detected if air masses originate from east and south, thus predominantly being of continental origin. From the elevated OHrad formation potencies in fall and winter a seasonal trend with low potencies in summers is assumed. Furthermore, source apportionment was performed by a positive matrix factor analysis, separating seven plausible factors which could be attributed to mineral dust, secondary nitrate, industry, non-exhaust traffic, fossil fuel combustion, marine aerosol and secondary aerosol factors. The intrinsic OHrad formation potency was found to be associated mainly with the fossil fuel combustion factor (45%) and industry factor (22%).

  13. The Relation between Fluid Intelligence and the General Factor as a Function of Cultural Background: A Test of Cattell's Investment Theory

    ERIC Educational Resources Information Center

    Kvist, Ann Valentin; Gustafsson, Jan-Eric

    2008-01-01

    According to Cattell's [Cattell, R.B. (1987). "Intelligence: Its structure, growth and action." New York: North-Holland.] Investment theory individual differences in acquisition of knowledge and skills are partly the result of investment of Fluid Intelligence ("Gf") in learning situations demanding insights in complex relations. If this theory…

  14. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  15. Confronting Twin Paradox Acceleration

    NASA Astrophysics Data System (ADS)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  16. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  17. The ATXN1 and TRIM31 genes are related to intelligence in an ADHD background: Evidence from a large collaborative study totaling 4,963 Subjects

    PubMed Central

    Rizzi, Thais S; Arias-Vasquez, Alejandro; Rommelse, Nanda; Kuntsi, Jonna; Anney, Richard; Asherson, Philip; Buitelaar, Jan; Banaschewski, Tobias; Ebstein, Richard; Ruano, Dina; Van der Sluis, Sophie; Markunas, Christina A; Garrett, Melanie E; Ashley-Koch, Allison E; Kollins, Scott H; Anastopoulos, Arthur D; Hansell, Narelle K; Wright, Margaret J; Montgomery, Grant W; Martin, Nicholas G; Harris, Sarah E; Davies, Gail; Tenesa, Albert; Porteous, David J; Starr, John M; Deary, Ian J; St. Pourcain, Beate; Smith, George Davey; Timpson, Nicholas J; Evans, David M; Gill, Michael; Miranda, Ana; Mulas, Fernando; Oades, Robert D; Roeyers, Herbert; Rothenberger, Aribert; Sergeant, Joseph; Sonuga-Barke, Edmund; Steinhausen, Hans Christoph; Taylor, Eric; Faraone, Stephen V; Franke, Barbara; Posthuma, Danielle

    2011-01-01

    Intelligence is a highly heritable trait for which it has proven difficult to identify the actual genes. In the past decade, five whole-genome linkage scans have suggested genomic regions important to human intelligence; however, so far none of the responsible genes or variants in those regions have been identified. Apart from these regions, a handful of candidate genes have been identified, although most of these are in need of replication. The recent growth in publicly available data sets that contain both whole genome association data and a wealth of phenotypic data, serves as an excellent resource for fine mapping and candidate gene replication. We used the publicly available data of 947 families participating in the International Multi-Centre ADHD Genetics (IMAGE) study to conduct an in silico fine mapping study of previously associated genomic locations, and to attempt replication of previously reported candidate genes for intelligence. Although this sample was ascertained for attention deficit/hyperactivity disorder (ADHD), intelligence quotient (IQ) scores were distributed normally. We tested 667 single nucleotide polymorphisms (SNPs) within 15 previously reported candidate genes for intelligence and 29451 SNPs in five genomic loci previously identified through whole genome linkage and association analyses. Significant SNPs were tested in four independent samples (4,357 subjects), one ascertained for ADHD, and three population-based samples. Associations between intelligence and SNPs in the ATXN1 and TRIM31 genes and in three genomic locations showed replicated association, but only in the samples ascertained for ADHD, suggesting that these genetic variants become particularly relevant to IQ on the background of a psychiatric disorder. © 2010 Wiley-Liss, Inc. PMID:21302343

  18. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  19. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  20. Osteogenic gene regulation and relative acceleration of healing by adenoviral-mediated transfer of human BMP-2 or -6 in equine osteotomy and ostectomy models.

    PubMed

    Ishihara, Akikazu; Shields, Kathleen M; Litsky, Alan S; Mattoon, John S; Weisbrode, Steven E; Bartlett, Jeffrey S; Bertone, Alicia L

    2008-06-01

    This study evaluated healing of equine metatarsal osteotomies and ostectomies in response to percutaneous injection of adenoviral (Ad) bone morphogenetic protein (BMP)-2, Ad-BMP-6, or beta-galactosidase protein vector control (Ad-LacZ) administered 14 days after surgery. Radiographic and quantitative computed tomographic assessment of bone formation indicated greater and earlier mineralized callus in both the osteotomies and ostectomies of the metatarsi injected with Ad-BMP-2 or Ad-BMP-6. Peak torque to failure and torsional stiffness were greater in osteotomies treated with Ad-BMP-2 than Ad-BMP-6, and both Ad-BMP-2- and Ad-BMP-6-treated osteotomies were greater than Ad-LacZ or untreated osteotomies. Gene expression of ostectomy mineralized callus 8 weeks after surgery indicated upregulation of genes related to osteogenesis compared to intact metatarsal bone. Expression of transforming growth factor beta-1, cathepsin H, and gelsolin-like capping protein were greater in Ad-BMP-2- and Ad-BMP-6-treated callus compared to Ad-LacZ-treated or untreated callus. Evidence of tissue biodistribution of adenovirus in distant organs was not identified by quantitative PCR, despite increased serum antiadenoviral vector antibody. This study demonstrated a greater relative potency of Ad-BMP-2 over Ad-BMP-6 in accelerating osteotomy healing when administered in this regimen, although both genes were effective at increasing bone at both osteotomy and ostectomy sites. PMID:18241059

  1. Accelerator vibration issues

    SciTech Connect

    Tennant, R.A.

    1985-01-01

    Vibrations induced in accelerator structures can cause particle-beam jitter and alignment difficulties. Sources of these vibrations may include pump oscillations, cooling-water turbulence, and vibrations transmitted through the floor to the accelerator structure. Drift tubes (DT) in a drift tube linac (DTL) are components likely to affect beam jitter and alignment because they normally have a heavy magnet structure on the end of a long and relatively small support stem. The natural vibrational frequencies of a drift tube have been compared with theoretical predictions. In principle, by knowing natural frequencies of accelerator components and system vibrational frequncies, an accelerator can be designed that does not have these frequencies coinciding. 2 refs., 2 figs., 2 tabs.

  2. One-loop stress-tensor renormalization in curved background: The relation between ζ-function and point-splitting approaches, and an improved point-splitting procedure

    NASA Astrophysics Data System (ADS)

    Moretti, Valter

    1999-08-01

    We conclude the rigorous analysis of a previous paper [V. Moretti, Commun. Math. Phys. 201, 327 (1999)] concerning the relation between the (Euclidean) point-splitting approach and the local ζ-function procedure to renormalize physical quantities at one-loop in (Euclidean) Quantum Field Theory in curved space-time. The case of the stress tensor is now considered in general D-dimensional closed manifolds for positive scalar operators -Δ+V(x). Results obtained formally in previous works [in the case D=4 and V(x)=ξR(x)+m2] are rigorously proven and generalized. It is also proven that, in static Euclidean manifolds, the method is compatible with Lorentzian-time analytic continuations. It is proven that the result of the ζ-function procedure is the same obtained from an improved version of the point-splitting method which uses a particular choice of the term w0(x,y) in the Hadamard expansion of the Green's function, given in terms of heat-kernel coefficients. This version of the point-splitting procedure works for any value of the field mass m. If D is even, the result is affected by an arbitrary one-parameter class of (conserved in absence of external source) symmetric tensors, dependent on the geometry locally, and it gives rise to the general correct trace expression containing the renormalized field fluctuations as well as the conformal anomaly term. Furthermore, it is proven that, in the case D=4 and V(x)=ξR(x)+m2, the given procedure reduces to the Euclidean version of Wald's improved point-splitting procedure provided the arbitrary mass scale present in the ζ-function is chosen opportunely. It is finally argued that the found point-splitting method should work generally, also dropping the hypothesis of a closed manifold, and not depending on the ζ-function procedure. This fact is indeed checked in the Euclidean section of Minkowski space-time for A=-Δ+m2 where the method gives rise to the correct Minkowski stress tensor for m2⩾0 automatically.

  3. Background sources at PEP

    SciTech Connect

    Lynch, H.; Schwitters, R.F.; Toner, W.T.

    1988-01-01

    Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, ..gamma..-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs.

  4. Building Background Knowledge

    ERIC Educational Resources Information Center

    Neuman, Susan B.; Kaefer, Tanya; Pinkham, Ashley

    2014-01-01

    This article make a case for the importance of background knowledge in children's comprehension. It suggests that differences in background knowledge may account for differences in understanding text for low- and middle-income children. It then describes strategies for building background knowledge in the age of common core standards.

  5. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  6. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)

  7. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  8. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  9. Vacancy-related defects in n-type Si implanted with a rarefied microbeam of accelerated heavy ions in the MeV range

    NASA Astrophysics Data System (ADS)

    Capan, I.; Pastuović, Ž.; Siegele, R.; Jaćimović, R.

    2016-04-01

    Deep level transient spectroscopy (DLTS) has been used to study vacancy-related defects formed in bulk n-type Czochralski-grown silicon after implantation of accelerated heavy ions: 6.5 MeV O, 10.5 MeV Si, 10.5 MeV Ge, and 11 MeV Er in the single ion regime with fluences from 109 cm-2 to 1010 cm-2 and a direct comparison made with defects formed in the same material irradiated with 0.7 MeV fast neutron fluences up to 1012 cm-2. A scanning ion microprobe was used as the ion implantation tool of n-Cz:Si samples prepared as Schottky diodes, while the ion beam induced current (IBIC) technique was utilized for direct ion counting. The single acceptor state of the divacancy V2(-/0) is the most prominent defect state observed in DLTS spectra of n-CZ:Si samples implanted by selected ions and the sample irradiated by neutrons. The complete suppression of the DLTS signal related to the double acceptor state of divacancy, V2(=/-) has been observed in all samples irradiated by ions and neutrons. Moreover, the DLTS peak associated with formation of the vacancy-oxygen complex VO in the neutron irradiated sample was also completely suppressed in DLTS spectra of samples implanted with the raster scanned ion microbeam. The reason for such behaviour is twofold, (i) the local depletion of the carrier concentration in the highly disordered regions, and (ii) the effect of the microprobe-assisted single ion implantation. The activation energy for electron emission for states assigned to the V2(-/0) defect formed in samples implanted by single ions follows the Meyer-Neldel rule. An increase of the activation energy is strongly correlated with increasing ion mass.

  10. Modeling of Particle Acceleration at Multiple Shocks Via Diffusive Shock Acceleration: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Parker, L. N.; Zank, G. P.

    2013-12-01

    Successful forecasting of energetic particle events in space weather models require algorithms for correctly predicting the spectrum of ions accelerated from a background population of charged particles. We present preliminary results from a model that diffusively accelerates particles at multiple shocks. Our basic approach is related to box models (Protheroe and Stanev, 1998; Moraal and Axford, 1983; Ball and Kirk, 1992; Drury et al., 1999) in which a distribution of particles is diffusively accelerated inside the box while simultaneously experiencing decompression through adiabatic expansion and losses from the convection and diffusion of particles outside the box (Melrose and Pope, 1993; Zank et al., 2000). We adiabatically decompress the accelerated particle distribution between each shock by either the method explored in Melrose and Pope (1993) and Pope and Melrose (1994) or by the approach set forth in Zank et al. (2000) where we solve the transport equation by a method analogous to operator splitting. The second method incorporates the additional loss terms of convection and diffusion and allows for the use of a variable time between shocks. We use a maximum injection energy (Emax) appropriate for quasi-parallel and quasi-perpendicular shocks (Zank et al., 2000, 2006; Dosch and Shalchi, 2010) and provide a preliminary application of the diffusive acceleration of particles by multiple shocks with frequencies appropriate for solar maximum (i.e., a non-Markovian process).

  11. Modeling of Particle Acceleration at Multiple Shocks via Diffusive Shock Acceleration: Preliminary Results

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Zank, G. P.

    2013-01-01

    Successful forecasting of energetic particle events in space weather models require algorithms for correctly predicting the spectrum of ions accelerated from a background population of charged particles. We present preliminary results from a model that diffusively accelerates particles at multiple shocks. Our basic approach is related to box models in which a distribution of particles is diffusively accelerated inside the box while simultaneously experiencing decompression through adiabatic expansion and losses from the convection and diffusion of particles outside the box. We adiabatically decompress the accelerated particle distribution between each shock by either the method explored in Melrose and Pope (1993) and Pope and Melrose (1994) or by the approach set forth in Zank et al. (2000) where we solve the transport equation by a method analogous to operator splitting. The second method incorporates the additional loss terms of convection and diffusion and allows for the use of a variable time between shocks. We use a maximum injection energy (E(sub max)) appropriate for quasi-parallel and quasi-perpendicular shocks and provide a preliminary application of the diffusive acceleration of particles by multiple shocks with frequencies appropriate for solar maximum (i.e., a non-Markovian process).

  12. Microwave inverse Cerenkov accelerator

    SciTech Connect

    Zhang, T.B.; Marshall, T.C.; LaPointe, M.A.; Hirshfield, J.L.

    1997-03-01

    A Microwave Inverse Cerenkov Accelerator (MICA) is currently under construction at the Yale Beam Physics Laboratory. The accelerating structure in MICA consists of an axisymmetric dielectrically lined waveguide. For the injection of 6 MeV microbunches from a 2.856 GHz RF gun, and subsequent acceleration by the TM{sub 01} fields, particle simulation studies predict that an acceleration gradient of 6.3 MV/m can be achieved with a traveling-wave power of 15 MW applied to the structure. Synchronous injection into a narrow phase window is shown to allow trapping of all injected particles. The RF fields of the accelerating structure are shown to provide radial focusing, so that longitudinal and transverse emittance growth during acceleration is small, and that no external magnetic fields are required for focusing. For 0.16 nC, 5 psec microbunches, the normalized emittance of the accelerated beam is predicted to be less than 5{pi}mm-mrad. Experiments on sample alumina tubes have been conducted that verify the theoretical dispersion relation for the TM{sub 01} mode over a two-to-one range in frequency. No excitation of axisymmetric or non-axisymmetric competing waveguide modes was observed. High power tests showed that tangential electric fields at the inner surface of an uncoated sample of alumina pipe could be sustained up to at least 8.4 MV/m without breakdown. These considerations suggest that a MICA test accelerator can be built to examine these predictions using an available RF power source, 6 MeV RF gun and associated beam line. {copyright} {ital 1997 American Institute of Physics.}

  13. Age-related expression of sigma1 receptors and antidepressant efficacy of a selective agonist in the senescence-accelerated (SAM) mouse.

    PubMed

    Phan, Vân-Ly; Miyamoto, Yoshiaki; Nabeshima, Toshitaka; Maurice, Tangui

    2005-02-15

    The sigma1 receptor is a unique intracellular receptor whose activation results in an efficient modulation of several neurotransmitter responses. Its role as a target for the rapid nongenomic effects of neuro(active)steroids and the age-related diminutions in steroid levels suggested that targeting the sigma1 receptor might allow alleviation of age-related neuronal dysfunctions. We examined here the expression and behavioral efficacy of sigma1 receptors in the senescence-accelerated (SAM) mouse model. The sigma1 receptor mRNA expression was measured by using comparative RT-PCR in the olfactory bulb, hippocampus, hypothalamus, cortex, or cerebellum of senescence-prone SAMP/8 and senescence-resistant SAMR/1 control animals. No difference was observed between substrains in 6-, 9-, and 12-month-old (m.o.) mice. The sigma1 protein expression was analyzed by using immunohistochemical techniques. Labeling was intense in the olfactory bulb, hippocampus, hypothalamus, and midbrain of both SAMR/1 and SAMP/8 mice, and the distribution appeared unchanged in 6-, 9-, and 12-m.o. animals. The receptor's in vivo availability was examined by using in vivo [3H](+)-SKF-10,047 binding. No age-related difference was observed in the olfactory bulb, hippocampus, hypothalamus, cortex, cerebellum, and brainstem of 6- or 12-m.o. SAMR/1 or SAMP/8 mice. The antidepressant efficacy of the selective agonist igmesine was examined in the forced-swimming test. The compound decreased significantly the immobility duration at 60 mg/kg in 6- and 12-m.o. SAMR/1 and in 6-m.o. SAMP/8 mice. In 12-m.o. SAMP/8 mice, the drug efficacy was facilitated; a significant effect was measured at 30 mg/kg. Decreased neurosteroid levels, particularly of progesterone, were seen in 12-m.o. SAMP/8 mice that might explain the enhanced efficacy of igmesine. Preserved sigma1 receptor expression and enhanced behavioral efficacy of sigma1 agonists were measured in SAM animals, confirming the therapeutic opportunities for

  14. The Cosmic Background Explorer.

    ERIC Educational Resources Information Center

    Gulkis, Samuel; And Others

    1990-01-01

    Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

  15. Observational probes of cosmic acceleration

    NASA Astrophysics Data System (ADS)

    Weinberg, David H.; Mortonson, Michael J.; Eisenstein, Daniel J.; Hirata, Christopher; Riess, Adam G.; Rozo, Eduardo

    2013-09-01

    The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of “dark energy” with exotic physical properties, or that Einstein’s theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit “Stage IV” dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H0. We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever

  16. Maritime infrared background clutter

    NASA Astrophysics Data System (ADS)

    Schwering, Piet B. W.

    1996-06-01

    The detection of small targets in maritime infrared surveillance is hampered by the presence of clutter. Sea surface structure, reflection and emission changes related to incident angle variations and surface effects are standard features governing the clutter behavior. Also special effects as sun glint and horizon effects play an important role for clutter. In order to optimize the detection process, quantitative clutter estimates are of use for filter settings. We have recorded a large amount of infrared backgrounds in the last few years, during common NATO trials. A large amount of different meteorological conditions took place during the various experiments. A first set of these data have been analyzed to obtain statistical data that represent the infrared scene. We have derived vertical temperature profiles, vertical fluctuation profiles, horizontal correlation coefficients and temporal correlation functions. In this paper we present the first analysis of these data. We are in the process of obtaining a condensed database of information to regenerate clutter images from bulk meteo parameters, and clutter parameters. The clutter and meteo parameters have been used to simulate various infrared scenes. Examples of this simulation process are shown in the presentation. The simulated images are statistically similar to the original images that were used to derive the parameters. A description of the image- generation is presented. Future expansions of the model are discussed.

  17. The cosmic background explorer

    SciTech Connect

    Gulkis, G. ); Lubin, P.M. ); Meyer, S.S. ); Silverberg, R.F.

    1990-01-01

    Late last year the National Aeronautics and Space Administration launched its first satellite dedicated to the study of phenomena related to the origins of the universe. The satellite, called the Cosmic Background Explorer (COBE), carries three complementary detectors that will make fundamental measurements of the celestial radiation. Part of that radiation is believed to have originated in processes that occurred at the very dawn of the universe. By measuring the remnant radiation at wavelengths from one micrometer to one centimeter across the entire sky, scientists hope to be able to solve many mysteries regarding the origin and evolution of the early universe. Unfortunately, these radiative relics of the early universe are weak and veiled by local astrophysical and terrestrial sources of radiation. The wavelengths of the various cosmic components may also overlap, thereby making the understanding of the diffuse celestial radiation a challenge. Nevertheless, the COBE instruments, with their full-sky coverage, high sensitivity to a wide range of wavelengths and freedom from interference from the earth's atmosphere, will constitute for astrophysicists an observatory of unprecedented sensitivity and scope. The interesting cosmic signals will then be separated from one another and from noncosmic radiation sources by a comprehensive analysis of the data.

  18. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  19. Backgrounds in Language.

    ERIC Educational Resources Information Center

    Maxwell, John C.; Long, Barbara K.

    "Backgrounds in Language," a field-tested inservice course designed for use by groups of 15 or 25 language arts teachers, provides the subject matter background teachers need to make informed decisions about what curriculum materials to use in what way, at what time, and with which students. The course is comprised of eight 2-hour sessions,…

  20. Correlators in nontrivial backgrounds

    SciTech Connect

    Mello Koch, Robert de; Ives, Norman; Stephanou, Michael

    2009-01-15

    Operators in N=4 super Yang-Mills theory with an R-charge of O(N{sup 2}) are dual to backgrounds which are asymtotically AdS{sub 5}xS{sup 5}. In this article we develop efficient techniques that allow the computation of correlation functions in these backgrounds. We find that (i) contractions between fields in the string words and fields in the operator creating the background are the field theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free field theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations.

  1. Data Series Subtraction with Unknown and Unmodeled Background Noise

    NASA Technical Reports Server (NTRS)

    Vitale, Stefano; Congedo, Giuseppe; Dolesi, Rita; Ferroni, Valerio; Hueller, Mauro; Vetrugno, Daniele; Weber, William Joseph; Audley, Heather; Danzmann, Karsten; Diepholz, Ingo; Hewitson, Martin; Korsakova, Natalia; Ferraioli, Luigi; Gibert, Ferran; Karnesis, Nikolaos; Nofrarias, Miquel; Inchauspe, Henri; Plagnol, Eric; Jennrich, Oliver; McNamara, Paul W.; Armano, Michele; Thorpe, James Ira; Wass, Peter

    2014-01-01

    LISA Pathfinder (LPF), the precursor mission to a gravitational wave observatory of the European Space Agency, will measure the degree to which two test masses can be put into free fall, aiming to demonstrate a suppression of disturbance forces corresponding to a residual relative acceleration with a power spectral density (PSD) below (30 fm/sq s/Hz)(sup 2) around 1 mHz. In LPF data analysis, the disturbance forces are obtained as the difference between the acceleration data and a linear combination of other measured data series. In many circumstances, the coefficients for this linear combination are obtained by fitting these data series to the acceleration, and the disturbance forces appear then as the data series of the residuals of the fit. Thus the background noise or, more precisely, its PSD, whose knowledge is needed to build up the likelihood function in ordinary maximum likelihood fitting, is here unknown, and its estimate constitutes instead one of the goals of the fit. In this paper we present a fitting method that does not require the knowledge of the PSD of the background noise. The method is based on the analytical marginalization of the posterior parameter probability density with respect to the background noise PSD, and returns an estimate both for the fitting parameters and for the PSD. We show that both these estimates are unbiased, and that, when using averaged Welchs periodograms for the residuals, the estimate of the PSD is consistent, as its error tends to zero with the inverse square root of the number of averaged periodograms. Additionally, we find that the method is equivalent to some implementations of iteratively reweighted least-squares fitting. We have tested the method both on simulated data of known PSD and on data from several experiments performed with the LISA Pathfinder end-to-end mission simulator.

  2. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  3. Magnetic Insulation for Electrostatic Accelerators

    SciTech Connect

    Grisham, L. R.

    2011-09-26

    The voltage gradient which can be sustained between electrodes without electrical breakdowns is usually one of the most important parameters in determining the performance which can be obtained in an electrostatic accelerator. We have recently proposed a technique which might permit reliable operation of electrostatic accelerators at higher electric field gradients, perhaps also with less time required for the conditioning process in such accelerators. The idea is to run an electric current through each accelerator stage so as to produce a magnetic field which envelopes each electrode and its electrically conducting support structures. Having the magnetic field everywhere parallel to the conducting surfaces in the accelerator should impede the emission of electrons, and inhibit their ability to acquire energy from the electric field, thus reducing the chance that local electron emission will initiate an arc. A relatively simple experiment to assess this technique is being planned. If successful, this technique might eventually find applicability in electrostatic accelerators for fusion and other applications.

  4. The cosmic neutrino background

    NASA Technical Reports Server (NTRS)

    Dar, Arnon

    1991-01-01

    The cosmic neutrino background is expected to consist of relic neutrinos from the big bang, of neutrinos produced during nuclear burning in stars, of neutrinos released by gravitational stellar collapse, and of neutrinos produced by cosmic ray interactions with matter and radiation in the interstellar and intergalactic medium. Formation of baryonic dark matter in the early universe, matter-antimatter annihilation in a baryonic symmetric universe, and dark matter annihilation could have also contributed significantly to the cosmic neutrino background. The purpose of this paper is to review the properties of these cosmic neutrino backgrounds, the indirect evidence for their existence, and the prospects for their detection.

  5. Adaptive background model

    NASA Astrophysics Data System (ADS)

    Lu, Xiaochun; Xiao, Yijun; Chai, Zhi; Wang, Bangping

    2007-11-01

    An adaptive background model aiming at outdoor vehicle detection is presented in this paper. This model is an improved model of PICA (pixel intensity classification algorithm), it classifies pixels into K-distributions by color similarity, and then a hypothesis that the background pixel color appears in image sequence with a high frequency is used to evaluate all the distributions to determine which presents the current background color. As experiments show, the model presented in this paper is a robust, adaptive and flexible model, which can deal with situations like camera motions, lighting changes and so on.

  6. Background Underground at WIPP

    NASA Astrophysics Data System (ADS)

    Esch, Ernst-Ingo; Hime, A.; Bowles, T. J.

    2001-04-01

    Recent interest to establish a dedicated underground laboratory in the United States prompted an experimental program at to quantify the enviromental backgrounds underground at the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. An outline of this program is provided along with recent experimental data on the cosmic ray muon flux at the 650 meter level of WIPP. The implications of the cosmic ray muon and fast neutron background at WIPP will be discussed in the context of new generation, low background experiments envisioned in the future.

  7. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  8. Electrostatic Plasma Accelerator (EPA)

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Aston, Graeme

    1989-01-01

    The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass. The goal of the present program is to demonstrate feasibility of the EPA thruster concept through experimental and theoretical investigations of the EPA acceleration mechanism and discharge chamber performance. Experimental investigations will include operating the test bed ion (TBI) engine as an EPA thruster and parametrically varying the thruster geometry and operating conditions to quantify the electrostatic plasma acceleration effect. The theoretical investigations will include the development of a discharge chamber model which describes the relationships between the engine size, plasma properties, and overall performance. For the EPA thruster to be a viable propulsion concept, overall thruster efficiencies approaching 30% with specific impulses approaching 1000 s must be achieved.

  9. The GLAST Background Model

    SciTech Connect

    Ormes, J.F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Mizuno, T.; Ritz, S.; /NASA, Goddard

    2007-10-17

    In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

  10. The GLAST Background Model

    SciTech Connect

    Ormes, J. F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Ritz, S.; Mizuno, T.

    2007-07-12

    In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

  11. Generative electronic background music system

    SciTech Connect

    Mazurowski, Lukasz

    2015-03-10

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions.

  12. High average power induction accelerators

    SciTech Connect

    Swingle, J.C.

    1985-10-01

    The induction accelerator is discussed with respect to general background and concept, beam transport, scaling, pulse power technology, and the electron beam injector. A discussion of the factors which affect the scaling of the intensity of the beam is given. Limiting factors include collective forces in the beam, virtual cathode formation, surroundings, and beam breakup instability. 24 refs., 11 figs. (WRF)

  13. Simple formulation of magnetoplasmadynamic acceleration

    SciTech Connect

    Sasoh, A. )

    1994-03-01

    A simple formulation of magnetoplasmadynamic acceleration has been made based on energy conservation relations and a generalized Ohm's law. An exhaust velocity is expressed using three characteristic parameters: (1) a dimensionless characteristic velocity [ital [tilde U

  14. Modeling of beam loss in Tevatron and backgrounds in the BTeV detector

    SciTech Connect

    Alexandr I. Drozhdin; Nikolai V. Mokhov

    2004-07-07

    Detailed STRUCT simulations are performed on beam loss rates in the vicinity of the BTeV detector in the Tevatron CO interaction region due to beam-gas nuclear elastic interactions and out-scattering from the collimation system. Corresponding showers induced in the machine components and background rates in BTeV are modeled with the MARS14 code. It is shown that the combination of a steel collimator and concrete shielding wall located in front of the detector can reduce the accelerator-related background rates in the detector by an order of magnitude.

  15. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  16. The Cosmic Background Explorer

    NASA Technical Reports Server (NTRS)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  17. The senescence-accelerated prone mouse (SAMP8): a model of age-related cognitive decline with relevance to alterations of the gene expression and protein abnormalities in Alzheimer's disease.

    PubMed

    Butterfield, D Allan; Poon, H Fai

    2005-10-01

    The senescence-accelerated mouse (SAM) is an accelerated aging model that was established through phenotypic selection from a common genetic pool of AKR/J strain of mice. The SAM model was established in 1981, including nine major senescence-accelerated mouse prone (SAMP) substrains and three major senescence-accelerated mouse resistant (SAMR) substrains, each of which exhibits characteristic disorders. Recently, SAMP8 have drawn attention in gerontological research due to its characteristic learning and memory deficits at old age. Many recent reports provide insight into mechanisms of the cognitive impairment and pathological changes in SAMP8. Therefore, this mini review examines the recent findings of SAMP8 mice abnormalities at the gene and protein levels. The genes and proteins described in this review are functionally categorized into neuroprotection, signal transduction, protein folding/degradation, cytoskeleton/transport, immune response and reactive oxygen species (ROS) production. All of these processes are involved in learning and memory. Although these studies provide insight into the mechanisms that contribute to the learning and memory decline in aged SAMP8 mice, higher throughput techniques of proteomics and genomics are necessary to study the alterations of gene expression and protein abnormalities in SAMP8 mice brain in order to more completely understand the central nervous system dysfunction in this mouse model. The SAMP8 is a good animal model to investigate the fundamental mechanisms of age-related learning and memory deficits at the gene and protein levels. PMID:16026957

  18. Berkeley Low Background Facility

    SciTech Connect

    Thomas, K. J.; Norman, E. B.; Smith, A. R.; Poon, A. W. P.; Chan, Y. D.; Lesko, K. T.

    2015-08-17

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.

  19. Berkeley Low Background Facility

    NASA Astrophysics Data System (ADS)

    Thomas, K. J.; Smith, A. R.; Poon, A. W. P.; Chan, Y. D.; Norman, E. B.; Lesko, K. T.

    2015-08-01

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.

  20. China: Background Notes Series.

    ERIC Educational Resources Information Center

    Reams, Joanne Reppert

    Concise background information on the People's Republic of China is provided. The publication begins with a profile of the country, outlining the people, geography, economy, and membership in international organizations. The bulk of the document then discusses in more detail China's people, geography, history, government, education, economy, and…

  1. Monitored background radiometer

    NASA Technical Reports Server (NTRS)

    Ruel, C.; Larouche, M.; Donato, M.

    1986-01-01

    The infrared (IR) testing of the Olympus thermal model has provided a capability to perform cost effective thermal balance testing of satellites and satellite components. A high-accuracy monitored background radiometer was developed for the measurement of absorbed radiation heat flux encountered during IR thermal vacuum testing of spacecraft. The design, development, and calibration of this radiometer is described.

  2. Nonthermal cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  3. Foregrounding the Background.

    ERIC Educational Resources Information Center

    Robbins, Bruce

    1998-01-01

    Argues that when introductory activities to the classics begin with background information, it can upstage or confine the life of the story, and shows little faith in the students as readers or in the literature itself. Suggests sometimes letting the literature begin, and then helping students make sense of it. Discusses examples from "To Kill a…

  4. Menopause accelerates biological aging.

    PubMed

    Levine, Morgan E; Lu, Ake T; Chen, Brian H; Hernandez, Dena G; Singleton, Andrew B; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E; Quach, Austin; Kusters, Cynthia D J; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E; Widschwendter, Martin; Ritz, Beate R; Absher, Devin; Assimes, Themistocles L; Horvath, Steve

    2016-08-16

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the "epigenetic clock"), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  5. Diffusive Shock Acceleration and Reconnection Acceleration Processes

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; Le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.; Cummings, A.; Stone, E.; Decker, R.

    2015-12-01

    Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and ion distributions downstream of interplanetary shocks and the heliospheric termination shock (HTS) are frequently inconsistent with the predictions of classical DSA. We utilize a recently developed transport theory for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets. Particle energization associated with the anti-reconnection electric field, a consequence of magnetic island merging, and magnetic island contraction, are considered. For the former only, we find that (i) the spectrum is a hard power law in particle speed, and (ii) the downstream solution is constant. For downstream plasmoid contraction only, (i) the accelerated spectrum is a hard power law in particle speed; (ii) the particle intensity for a given energy peaks downstream of the shock, and the distance to the peak location increases with increasing particle energy, and (iii) the particle intensity amplification for a particular particle energy, f(x,c/{c}0)/f(0,c/{c}0), is not 1, as predicted by DSA, but increases with increasing particle energy. The general solution combines both the reconnection-induced electric field and plasmoid contraction. The observed energetic particle intensity profile observed by Voyager 2 downstream of the HTS appears to support a particle acceleration mechanism that combines both DSA and magnetic-island-reconnection-related processes.

  6. Pulsed electromagnetic gas acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1971-01-01

    Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.

  7. Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries

    NASA Astrophysics Data System (ADS)

    Lima, Marta

    2013-04-01

    Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries Lima, Marta1; Menor, Eldemar2; Lima, Enjolras3; Neumann, Virginio4 1MFGTransportes, Brazil; 2Federal University of Pernambuco, Brazil 3Servico Geologico do Brasil-CPRM, Brazil 4Federal University of Pernambuco, Brazil Heavy metal (HM) concentrations in estuarine sediments of the Botafogo and Manguaba river, North-eastern Brazil were investigated on basis of samples from a bottom core drill performed 4km from the mouth of the rivers. Total sediments (TS) of the sliced profiles (62 cm, Botafogo river and 87 cm, Manguaba river ) were submitted to chemical analysis (51 elements), mineralogical analysis (XRD) and statistical study, followed by stoichiometric calculations. Geochronologic determinations of 210Pb allowed studying the evolution of the contamination level approximately 150 year-old interval in the Botafogo river. Mercury (Hg) and Arsenic (As) are emphasized because of a chlorine-soda industry that dumps its effluents about 15 km upstream of the estuary and extensive cultivation of sugarcane existent in this watershed. Hg background in pelitic total sediments (PTS) was certain established considering the Hg content (126 ppb) in sedimentary intervals previous to 1910. The production of chlorine-soda (since 1963) coincides with a drastic increase of the Hg concentrations and contemporary values around 6.000 ppb, without interruption in the pollutant process. The conclusions found that the Hg was the main indicator of anthropogenic contribution in the sediments of the Botafogo river. On the other hand, an increase in the Hg-As concentrations has been observed at the last decades due to an increase of the clay mineral fraction in TS of the Manguaga river. This scenario indicates that the accumulation of HM has been constant since the last decades, under a

  8. 22 CFR 305.3 - Background investigations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Background investigations. 305.3 Section 305.3 Foreign Relations PEACE CORPS ELIGIBILITY AND STANDARDS FOR PEACE CORPS VOLUNTEER SERVICE § 305.3 Background investigations. Section 22 of the Peace Corps Act states that to ensure enrollment of a...

  9. 22 CFR 305.3 - Background investigations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Background investigations. 305.3 Section 305.3 Foreign Relations PEACE CORPS ELIGIBILITY AND STANDARDS FOR PEACE CORPS VOLUNTEER SERVICE § 305.3 Background investigations. Section 22 of the Peace Corps Act states that to ensure enrollment of a...

  10. 22 CFR 305.3 - Background investigations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Background investigations. 305.3 Section 305.3 Foreign Relations PEACE CORPS ELIGIBILITY AND STANDARDS FOR PEACE CORPS VOLUNTEER SERVICE § 305.3 Background investigations. Section 22 of the Peace Corps Act states that to ensure enrollment of a...

  11. 22 CFR 305.3 - Background investigations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Background investigations. 305.3 Section 305.3 Foreign Relations PEACE CORPS ELIGIBILITY AND STANDARDS FOR PEACE CORPS VOLUNTEER SERVICE § 305.3 Background investigations. Section 22 of the Peace Corps Act states that to ensure enrollment of a...

  12. Pulsed electromagnetic gas acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1974-01-01

    Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.

  13. Two-beam accelerator

    SciTech Connect

    Selph, F.B.

    1984-09-01

    In the two-beam accelerator (TBA) concept, an electron linear accelerator structure is established in which two beams propagate. One is an intense low energy beam that is made to undergo free electron lasing to produce microwaves. These microwaves are then coupled to another part of the structure where they act to produce a high longitudinal electric gradient that is used to accelerate a second relatively low intensity electron beam to very high energies. The TBA was originally suggested by Sessler as a possible means for economically achieving linear collider energies of 100 GeV and above. Although still in a conceptual stage, the TBA is an inherently plausible concept that combines the free electron laser (FEL) with several well-known technologies - high current induction linacs, microwave waveguides, and traveling-wave linac structures - in a novel and interesting way. Two characteristics of the TBA that make it a particularly suitable candidate for achieving high energies are its ability to operate at higher frequencies than typical present-day linacs (say 30 GHz as compared with 3 GHz), and to be an efficient means for delivering power to a hitherto unattainable high-gradient structure (say 250 MV/m) that the higher frequency makes possible. These high accelerating gradients will permit much shorter linac structures for a given energy.

  14. Hugoniot analysis of the ram accelerator

    NASA Astrophysics Data System (ADS)

    Knowlen, C.; Bruckner, A. P.

    The thermodynamic properties of a combustible propellant gas, after it has been processed by a ram accelerator propulsive mode, are related by a 'ram accelerator Hugoniot' expression. These end states are determined from the 1-D conservation equations in a manner similar to that used for detonation waves, but with the addition of a force term in the momentum equation. Establishment of a region of potentially accessible thermodynamic end states that are consistent with ram accelerator operation at and above the Chapman-Jouguet detonation speed indicates that there are no fundamental constraints on accelerating projectiles over a wide range of Mach numbers in a single propellant mixture. Interpreting experimental data in the context of a generalized ram accelerator process leads to relatively simple propulsive models which can predict the projectile acceleration of any propulsive mode. The projectile velocity and acceleration histories determined by the Hugoniot analysis for the thermally choked ram accelerator mode are in excellent agreement with experiments.

  15. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence. PMID:17799689

  16. Efficient particle acceleration in shocks

    NASA Astrophysics Data System (ADS)

    Heavens, A. F.

    1984-10-01

    A self-consistent non-linear theory of acceleration of particles by shock waves is developed, using an extension of the two-fluid hydrodynamical model by Drury and Völk. The transport of the accelerated particles is governed by a diffusion coefficient which is initially assumed to be independent of particle momentum, to obtain exact solutions for the spectrum. It is found that steady-state shock structures with high acceleration efficiency are only possible for shocks with Mach numbers less than about 12. A more realistic diffusion coefficient is then considered, and this maximum Mach number is reduced to about 6. The efficiency of the acceleration process determines the relative importance of the non-relativistic and relativistic particles in the distribution of accelerated particles, and this determines the effective specific heat ratio.

  17. Maximal acceleration and radiative processes

    NASA Astrophysics Data System (ADS)

    Papini, Giorgio

    2015-08-01

    We derive the radiation characteristics of an accelerated, charged particle in a model due to Caianiello in which the proper acceleration of a particle of mass m has the upper limit 𝒜m = 2mc3/ℏ. We find two power laws, one applicable to lower accelerations, the other more suitable for accelerations closer to 𝒜m and to the related physical singularity in the Ricci scalar. Geometrical constraints and power spectra are also discussed. By comparing the power laws due to the maximal acceleration (MA) with that for particles in gravitational fields, we find that the model of Caianiello allows, in principle, the use of charged particles as tools to distinguish inertial from gravitational fields locally.

  18. Background illumination simulator

    SciTech Connect

    Towry, E.R.

    1992-05-12

    This patent describes a testing apparatus for testing and evaluating the performance of laser seeking warheads for missiles, under simulated weather conditions. It comprises support means for supporting a warhead seeker; laser means for generating a laser beam and for directing a laser beam towards the seeker; a diffusion screen interposed between the seeker support means and the laser means for diffusing the laser beam; a collimating lens interposed between the diffusion screen and the seeker support means for collimating the diffused laser beam and for directing the collimated laser beam onto a warhead seeker, supported in the seeker support; background illuminator means for illuminating the seeker support and a seeker disposed therein, supported for movement into and out of an operating position between the diffusion means and the collimating lens for providing background lighting in simulation of weather lighting conditions; and control means for controlling the intensity of the light provided by the illuminator means to simulate various weather conditions.

  19. Some background about satellites

    NASA Technical Reports Server (NTRS)

    Burns, Joseph A.

    1986-01-01

    Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.

  20. Accelerating cleanup: Paths to closure

    SciTech Connect

    1998-06-01

    This report describes the status of Environmental Management`s (EM`s) cleanup program and a direction forward to complete achievement of the 2006 vision. Achieving the 2006 vision results in significant benefits related to accomplishing EM program objectives. As DOE sites accelerate cleanup activities, risks to public health, the environment, and worker safety and health are all reduced. Finding more efficient ways to conduct work can result in making compliance with applicable environmental requirements easier to achieve. Finally, as cleanup activities at sites are completed, the EM program can focus attention and resources on the small number of sites with more complex cleanup challenges. Chapter 1 describes the process by which this report has been developed and what it hopes to accomplish, its relationship to the EM decision-making process, and a general background of the EM mission and program. Chapter 2 describes how the site-by-site projections were constructed, and summarizes, for each of DOE`s 11 Operations/Field Offices, the projected costs and schedules for completing the cleanup mission. Chapter 3 presents summaries of the detailed cleanup projections from three of the 11 Operations/Field Offices: Rocky Flats (Colorado), Richland (Washington), and Savannah River (South Carolina). The remaining eight Operations/Field Office summaries are in Appendix E. Chapter 4 reviews the cost drivers, budgetary constraints, and performance enhancements underlying the detailed analysis of the 353 projects that comprise EM`s accelerated cleanup and closure effort. Chapter 5 describes a management system to support the EM program. Chapter 6 provides responses to the general comments received on the February draft of this document.

  1. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  2. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V. ); Connolly, R.; Weiss, R. (Gr

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  3. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-09-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth`s magnetic field and travel in straight lines unless they enter the earth`s atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  4. Accelerators for Cancer Therapy

    DOE R&D Accomplishments Database

    Lennox, Arlene J.

    2000-05-30

    The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.

  5. Backgrounds Data Center

    NASA Astrophysics Data System (ADS)

    Snyder, William A.; Gursky, Herbert; Heckathorn, Harry M.; Lucke, Bob L.; Dorland, Bryan N.; Kessel, R. A.; Berg, S. L.; Dombrowski, E. G.

    1994-09-01

    The Backgrounds Data Center (BDC) is the designated archive for backgrounds data collected by Ballistic Missile Defense Organization (BMDO) programs, some of which include ultraviolet sensors. Currently, the BDC holds ultraviolet data from the IBSS, UVPI, UVLIM, and FUVCAM sensors. The BDC will also be the prime archive for Midcourse Space Experiment (MSX) data and is prepared to negotiate with program managers to handle other datasets. The purpose of the BDC is to make data accessible to users and to assist them in analyzing it. The BDC maintains the Science Catalog Information Exchange System (SCIES) allowing remote users to log in, read or post notices about current programs, search the catalogs for datasets of interest, and submit orders for data. On-site facilities are also available for the analysis of data, and consist of VMS and UNIX workstations with access to software analysis packages such as IDL, IRAF, and Khoros. Either on-site or remotely, users can employ the BDC-developed graphical user interface called the Visual Interface for Space and Terrestrial Analysis (VISTA) to generate catalog queries and to display and analyze data. SCIES and VISTA permit nearly complete access to BDC services and capabilities without the need to be physically present at the data center.

  6. The Backgrounds Data Center

    NASA Technical Reports Server (NTRS)

    Snyder, W. A.; Gursky, H.; Heckathorn, H. M.; Lucke, R. L.; Berg, S. L.; Dombrowski, E. G.; Kessel, R. A.

    1993-01-01

    The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible.

  7. Homolytic dissociation of the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and structures and stabilities of the related radicals Me2NCSn* (n = 1-4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Mak, Adrian Matthew; Wong, Ming Wah

    2006-12-01

    The homolytic dissociation of the important vulcanization accelerator tetramethylthiuram disulfide (TMTD) has been studied by ab initio calculations according to the G3X(MP2) and G3X(MP2)-RAD theories. Homolytic cleavage of the SS bond requires a low enthalpy of 150.0 kJ mol-1, whereas 268.0 kJ mol-1 is needed for the dissociation of one of the C-S single bonds. To cleave one of the SS bonds of the corresponding trisulfide (TMTT) requires 191.1 kJ mol-1. Me2NCS2* is a particularly stable sulfur radical as reflected in the low S-H bond dissociation enthalpy of the corresponding acid Me2NC(=S)SH (301.7 kJ mol-1). Me2NCS2* (2B2) is a sigma radical characterized by the unpaired spin density shared equally between the two sulfur atoms and by a 4-center (NCS2) delocalized pi system. The ESR g-tensors of the radicals Me2NCSn* (n = 1-3) have been calculated. Both TMTD and the mentioned radicals form stable chelate complexes with a Li+ cation, which here serves as a model for the zinc ions used in accelerated rubber vulcanization. Although the binding energy of the complex [Li(TMTD)]+ is larger than that of the isomeric species [Li(S2CNMe2)2]+ (12), the dissociation enthalpy of TMTD as a ligand is smaller (125.5 kJ mol-1) than that of free TMTD. In other words, the homolytic dissociation of the SS bonds of TMTD is facilitated by the presence of Li+ ions. The sulfurization of TMTD in the presence of Li+ to give the paramagnetic complex [Li(S3CNMe2)2]+ is strongly exothermic. These results suggest that TMTD reacts with naked zinc ions as well as with the surface atoms of solid zinc oxide particles in an analogous manner producing highly reactive complexes, which probably initiate the crosslinking process during vulcanization reactions of natural or synthetic rubber accelerated by TMTD/ZnO. PMID:17137356

  8. 32 CFR 1292.3 - Background.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of...

  9. Electrostatic Plasma Accelerator (EPA)

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Aston, Graeme

    1995-01-01

    The application of electric propulsion to communications satellites, however, has been limited to the use of hydrazine thrusters with electric heaters for thrust and specific impulse augmentation. These electrothermal thrusters operate at specific impulse levels of approximately 300 s with heater powers of about 500 W. Low power arcjets (1-3 kW) are currently being investigated as a way to increase specific impulse levels to approximately 500 s. Ion propulsion systems can easily produce specific impulses of 3000 s or greater, but have yet to be applied to communications satellites. The reasons most often given for not using ion propulsion systems are their high level of overall complexity, low thrust with long burn times, and the difficulty of integrating the propulsion system into existing commercial spacecraft busses. The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass.

  10. Space charge compensation in laser particle accelerators

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    1999-07-01

    Laser particle acceleration (LPA) involves the acceleration of particle beams by electromagnetic waves with relatively short wavelength compared with conventional radio-frequency systems. These short length scales raise the question whether space charge effects may be a limiting factor in LPA performance. This is analyzed in two parts of an accelerator system, the acceleration sections and the drift region of the prebuncher. In the prebuncher, space charge can actually be converted to an advantage for minimizing the energy spread. In the accelerator sections, the laser fields can compensate for space charge forces, but the compensation becomes weaker for high beam energy.