WorldWideScience

Sample records for strong gpa dependence

  1. Pressure-dependent decomposition kinetics of the energetic material HMX up to 3.6 GPa.

    Science.gov (United States)

    Glascoe, Elizabeth A; Zaug, Joseph M; Burnham, Alan K

    2009-12-03

    The effect of pressure on the global thermal decomposition rate of the energetic material HMX was studied. HMX was precompressed in a diamond anvil cell (DAC) and heated at various rates. The parent species population was monitored as a function of time and temperature using Fourier transform infrared (FTIR) spectroscopy. Global decomposition rates were determined by fitting the fraction reacted to the extended-Prout-Tompkins nucleation-growth model and the Friedman isoconversional method. The results of these experiments and analysis indicate that pressure accelerates the decomposition at low-to-moderate pressures (i.e., between ambient pressure and 0.1 GPa) and decelerates the decomposition at higher pressures. The decomposition acceleration is attributed to pressure-enhanced autocatalysis, whereas the deceleration at high pressures is attributed to pressure-inhibiting bond homolysis step(s), which would result in an increase in volume. These results indicate that both the beta- and delta-polymorphs of HMX are sensitive to pressure in the thermally induced decomposition kinetics.

  2. Deep Ocean Sound Propagation in Environments with Strong Range Dependence

    Science.gov (United States)

    2010-09-30

    follow carbon dioxide uptake into the ocean from the atmosphere have been modeled to have a small but potentially detectable impact on ocean acoustic...to scattering). This work is being presented at the NPAL workshop. 8. Ambient noise level change due to ocean acidification A simplified model...range dependence. In addition, a study of oceanic acoustic response to acidification has been made. IMPACT/APPLICATIONS The research described

  3. Strong dependence of ultracold chemical rates on electric dipole moments

    International Nuclear Information System (INIS)

    Quemener, Goulven; Bohn, John L.

    2010-01-01

    We use the quantum threshold laws combined with a classical capture model to provide an analytical estimate of the chemical quenching cross sections and rate coefficients of two colliding particles at ultralow temperatures. We apply this quantum threshold model (QT model) to indistinguishable fermionic polar molecules in an electric field. At ultracold temperatures and in weak electric fields, the cross sections and rate coefficients depend only weakly on the electric dipole moment d induced by the electric field. In stronger electric fields, the quenching processes scale as d 4(L+(1/2)) where L>0 is the orbital angular-momentum quantum number between the two colliding particles. For p-wave collisions (L=1) of indistinguishable fermionic polar molecules at ultracold temperatures, the quenching rate thus scales as d 6 . We also apply this model to pure two-dimensional collisions and find that chemical rates vanish as d -4 for ultracold indistinguishable fermions. This model provides a quick and intuitive way to estimate chemical rate coefficients of reactions occuring with high probability.

  4. GPA Homepage -- Present and future

    International Nuclear Information System (INIS)

    Harris, S.C.

    1997-01-01

    The Gas Processors Association has established its presence on the Internet through the development of its Web Page. This site will continue to be developed and expanded so as to strive towards the goal defined in the GPA mission statement of delivering value to the global membership. The current address for the site is http://www.galstar.com/~gpa

  5. Wavelength dependence of light diffusion in strongly scattering macroporous gallium phosphide

    NARCIS (Netherlands)

    Peeters, W.H.; Vellekoop, Ivo Micha; Mosk, Allard; Lagendijk, Aart

    2008-01-01

    We present time-resolved measurements of light transport through strongly scattering macroporous gallium phosphide at various vacuum wavelengths between 705 nm and 855 nm. Within this range the transport mean free path is strongly wavelength dependent, whereas the observed energy velocity is shown

  6. Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region

    Directory of Open Access Journals (Sweden)

    N.I. Kashirina

    2017-12-01

    Full Text Available The properties of translationally invariant polaron functional have been investigated in the region of strong and extremely strong coupling. It has been shown that the Gross–Tulub polaron functional obtained earlier using the methods of field theory was derived only for the region , where is the Fröhlich constant of the electron-phonon coupling. Various representations of exact and approximate polaron functionals have been considered. Asymptotic dependences of the polaron energy have been obtained using a functional extending the Gross–Tulub functional to the region of extremely strong coupling. The asymptotic dependence of polaron energies for an extremely strong coupling are (for the one-parameter variational function fk, and (for a two-parameter function . It has been shown that the virial theorem 1:3:4 holds for the two-parameter function . Minimization of the approximate functional obtained by expanding the exact Gross–Tulub functional in a series on leads to a quadratic dependence of the polaron energy. This approximation is justified for . For a two-parameter function , the corresponding dependence has the form . However, the use of approximate functionals, in contrast to the strict variational procedure, when the exact polaron functional varies, does not guarantee obtaining the upper limit for the polaron energy.

  7. Interpretation of the temperature dependence of the strong visible photoluminescence of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Finkbeiner, S. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Weber, J. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 70569 Stuttgart (Germany)

    1995-01-15

    The temperature dependence of the strong visible photoluminescence (550-850nm) is studied in differently prepared porous silicon samples. The variation in the photoluminescence intensity with temperature is a result of a decrease in the radiative decay time and an increase in the non-radiative recombination process with increasing temperatures. The strong visible photoluminescence is interpreted by a recombination of singlet and triplet excitons. The singlet-triplet splitting is comparable for all samples but depends on the detection wavelength and on sample preparation. We present similar data for the recombination process in siloxene which supports the model of a common origin of the strong visible photoluminescence in these very differently prepared samples. ((orig.))

  8. Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory.

    Science.gov (United States)

    Sissay, Adonay; Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J; Lopata, Kenneth

    2016-09-07

    Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

  9. Density-dependent electron scattering in photoexcited GaAs in strongly diffusive regime

    DEFF Research Database (Denmark)

    Mics, Zoltán; D’Angio, Andrea; Jensen, Søren A.

    2013-01-01

    In a series of systematic optical pump–terahertz probe experiments, we study the density-dependent electron scattering rate in photoexcited GaAs in the regime of strong carrier diffusion. The terahertz frequency-resolved transient sheet conductivity spectra are perfectly described by the Drude...... model, directly yielding the electron scattering rates. A diffusion model is applied to determine the spatial extent of the photoexcited electron-hole gas at each moment after photoexcitation, yielding the time-dependent electron density, and hence the density-dependent electron scattering time. We find...... that the electron scattering time decreases from 320 to 60 fs, as the electron density changes from 1015 to 1019 cm−3....

  10. On the penetration of a hot diapir through a strongly temperature-dependent viscosity medium

    Science.gov (United States)

    Daly, S. F.; Raefsky, A.

    1985-01-01

    The ascent of a hot spherical body through a fluid with a strongly temperature-dependent viscosity has been studied using an axisymmetric finite element method. Numerical solutions range over Peclet numbers of 0.1 - 1000 from constant viscosity up to viscosity variations of 100,000. Both rigid and stress-free boundary conditions were applied at the surface of the sphere. The dependence of drag on viscosity variation was shown to have no dependence on the stress boundary condition except for a Stokes flow scaling factor. A Nusselt number parameterization based on the stress-free constant viscosity functional dependence on the Peclet number scaled by a parameter depending on the viscosity structure fits both stress-free and rigid boundary condition data above viscosity variations of 100. The temperature scale height was determined as a function of sphere radius. For the simple physical model studied in this paper pre-heating is required to reduce the ambient viscosity of the country rock to less than 10 to the 22nd sq cm/s in order for a 10 km diapir to penetrate a distance of several radii.

  11. Extraordinary Photoluminescence and Strong Temperature/Angle-Dependent Raman Responses in Few-Layer Phosphorene

    OpenAIRE

    Zhang, Shuang; Yang, Jiong; Xu, Renjing; Wang, Fan; Li, Weifeng; Ghufran, Muhammad; Zhang, Yong-wei; Yu, Zongfu; Zhang, Gang; Qin, Qinghua; Lu, Yuerui

    2014-01-01

    Phosphorene is a new family member of two-dimensional materials. We observed strong and highly layer-dependent photoluminescence in few-layer phosphorene (2 to 5 layers). The results confirmed the theoretical prediction that few-layer phosphorene has a direct and layer-sensitive band gap. We also demonstrated that few-layer phosphorene is more sensitive to temperature modulation than graphene and MoS2 in Raman scattering. The anisotropic Raman response in few-layer phosphorene has enabled us ...

  12. Strong temperature dependence of extraordinary magnetoresistance correlated to mobility in a two-contact device

    KAUST Repository

    Sun, Jian

    2012-02-21

    A two-contact extraordinary magnetoresistance (EMR) device has been fabricated and characterized at various temperatures under magnetic fields applied in different directions. Large performance variations across the temperature range have been found, which are due to the strong dependence of the EMR effect on the mobility. The device shows the highest sensitivity of 562ω/T at 75 K with the field applied perpendicularly. Due to the overlap between the semiconductor and the metal shunt, the device is also sensitive to planar fields but with a lower sensitivity of about 20 to 25% of the one to perpendicular fields. © 2012 The Japan Society of Applied Physics.

  13. Intensity dependent waiting time for strong electron trapping events in speckle stimulated raman scatter

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Harvey [Los Alamos National Laboratory; Daughton, W [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory

    2009-01-01

    The onset of Stimulated Raman scatter from an intense laser speckle is the simplest experimentally realizable laser-plasma-interaction environment. Despite this data and recent 3D particle simulations, the controlling mechanism at the onset of backscatter in the kinetic regime when strong electron trapping in the daughter Langmuir wave is a dominant nonlinearity is not understood. This paper explores the consequences of assuming that onset is controlled by large thermal fluctuations. A super exponential dependence of mean reflectivity on speckle intensity in the onset regime is predicted.

  14. Extraordinary photoluminescence and strong temperature/angle-dependent Raman responses in few-layer phosphorene.

    Science.gov (United States)

    Zhang, Shuang; Yang, Jiong; Xu, Renjing; Wang, Fan; Li, Weifeng; Ghufran, Muhammad; Zhang, Yong-Wei; Yu, Zongfu; Zhang, Gang; Qin, Qinghua; Lu, Yuerui

    2014-09-23

    Phosphorene is a new family member of two-dimensional materials. We observed strong and highly layer-dependent photoluminescence in few-layer phosphorene (two to five layers). The results confirmed the theoretical prediction that few-layer phosphorene has a direct and layer-sensitive band gap. We also demonstrated that few-layer phosphorene is more sensitive to temperature modulation than graphene and MoS2 in Raman scattering. The anisotropic Raman response in few-layer phosphorene has enabled us to use an optical method to quickly determine the crystalline orientation without tunneling electron microscopy or scanning tunneling microscopy. Our results provide much needed experimental information about the band structures and exciton nature in few-layer phosphorene.

  15. Fast gain recovery rates with strong wavelength dependence in a non-linear SOA.

    Science.gov (United States)

    Cleary, Ciaran S; Power, Mark J; Schneider, Simon; Webb, Roderick P; Manning, Robert J

    2010-12-06

    We report remarkably fast and strongly wavelength-dependent gain recovery in a single SOA without the aid of an offset filter. Full gain recovery times as short as 9 ps were observed in pump-probe measurements when pumping to the blue wavelength side of a continuous wave probe, in contrast to times of 25 to 30 ps when pumping to the red wavelength side. Experimental and numerical analysis indicate that the long effective length and high gain led to deep saturation of the second half of the SOA by the probe. The consequent absorption of blue-shifted pump pulses in this region resulted in device dynamics analogous to those of the Turbo-Switch.

  16. Strongly enhanced temperature dependence of the chemical potential in FeSe

    Science.gov (United States)

    Rhodes, L. C.; Watson, M. D.; Haghighirad, A. A.; Eschrig, M.; Kim, T. K.

    2017-05-01

    Employing a 10-orbital tight-binding model, we present a set of hopping parameters fitted directly to our latest high-resolution angle-resolved photoemission spectroscopy (ARPES) data for the high-temperature tetragonal phase of FeSe. Using these parameters, we predict a large 10 meV shift of the chemical potential as a function of temperature. To confirm this large temperature dependence, we performed ARPES experiments on FeSe and observed a ˜25 meV rigid shift to the chemical potential between 100 and 300 K. This strong shift has important implications for theoretical models of superconductivity and of nematic order in FeSe materials.

  17. Observations of height-dependent pressure-perturbation structure of a strong mesoscale gravity wave

    Science.gov (United States)

    Starr, David O'C.; Korb, C. L.; Schwemmer, Geary K.; Weng, Chi Y.

    1992-01-01

    Airborne observations using a downward-looking, dual-frequency, near-infrared, differential absorption lidar system provide the first measurements of the height-dependent pressure-perturbation field associated with a strong mesoscale gravity wave. A pressure-perturbation amplitude of 3.5 mb was measured within the lowest 1.6 km of the atmosphere over a 52-km flight line. Corresponding vertical displacements of 250-500 m were inferred from lidar-observed displacement of aerosol layers. Accounting for probable wave orientation, a horizontal wavelength of about 40 km was estimated. Satellite observations reveal wave structure of a comparable scale in concurrent cirrus cloud fields over an extended area. Smaller-scale waves were also observed. Local meteorological soundings are analyzed to confirm the existence of a suitable wave duct. Potential wave-generation mechanisms are examined and discussed. The large pressure-perturbation wave is attributed to rapid amplification or possible wave breaking of a gravity wave as it propagated offshore and interacted with a very stable marine boundary layer capped by a strong shear layer.

  18. Ascaroside expression in Caenorhabditis elegans is strongly dependent on diet and developmental stage.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    2011-03-01

    Full Text Available The ascarosides form a family of small molecules that have been isolated from cultures of the nematode Caenorhabditis elegans. They are often referred to as "dauer pheromones" because most of them induce formation of long-lived and highly stress resistant dauer larvae. More recent studies have shown that ascarosides serve additional functions as social signals and mating pheromones. Thus, ascarosides have multiple functions. Until now, it has been generally assumed that ascarosides are constitutively expressed during nematode development.Cultures of C. elegans were developmentally synchronized on controlled diets. Ascarosides released into the media, as well as stored internally, were quantified by LC/MS. We found that ascaroside biosynthesis and release were strongly dependent on developmental stage and diet. The male attracting pheromone was verified to be a blend of at least four ascarosides, and peak production of the two most potent mating pheromone components, ascr#3 and asc#8 immediately preceded or coincided with the temporal window for mating. The concentration of ascr#2 increased under starvation conditions and peaked during dauer formation, strongly supporting ascr#2 as the main population density signal (dauer pheromone. After dauer formation, ascaroside production largely ceased and dauer larvae did not release any ascarosides. These findings show that both total ascaroside production and the relative proportions of individual ascarosides strongly correlate with these compounds' stage-specific biological functions.Ascaroside expression changes with development and environmental conditions. This is consistent with multiple functions of these signaling molecules. Knowledge of such differential regulation will make it possible to associate ascaroside production to gene expression profiles (transcript, protein or enzyme activity and help to determine genetic pathways that control ascaroside biosynthesis. In conjunction with findings

  19. Strong composition-dependent disorder in InAs1-xNx alloys

    International Nuclear Information System (INIS)

    Benaissa, H.; Zaoui, A.; Ferhat, M.

    2009-01-01

    We investigate the main causes of disorder in the InAs 1-x N x alloys (x = 0, 0.03125, 0.0625, 0.09375, 0.125, 0.25, 0.5, 0.75, 0.875, 0.90625, 0.9375, 0.96875 and 1). The calculation is based on the density-functional theory in the local-density approximation. We use a plane wave-expansion non-norm conserving ab initio Vanderbilt pseudopotentials. To avoid the difficulty of considering the huge number of atomic configurations, we use an appropriate strategy in which we consider four configurations for a given composition where the N atoms are not randomly distributed. We mainly show that the band gap decreases (increases) rapidly with increasing (decreasing) compositions of N. As a consequence the optical band gap bowing is found to be strong and composition dependent. The obtained compounds, from these alloys, may change from semi-conducting to metal (passing to a negative bowing) and could be useful for device applications, especially at certain composition.

  20. A strong angular dependence of magnetic properties of magnetosome chains: Implications for rock magnetism and paleomagnetism

    Science.gov (United States)

    Li, Jinhua; Ge, Kunpeng; Pan, Yongxin; Williams, Wyn; Liu, Qingsong; Qin, Huafeng

    2013-10-01

    Single-domain magnetite particles produced by magnetotactic bacteria (magnetosomes) and aligned in chains are of great interest in the biosciences and geosciences. Here, we investigated angular variation of magnetic properties of aligned Magnetospirillum magneticum AMB-1 cells, each of which contains one single fragmental chain of magnetosomes. With measurements at increasing angles from the chain direction, we observed that (i) the hysteresis loop gradually changes from nearly rectangular to a ramp-like shape (e.g., Bc and remanence decrease), (ii) the acquisition and demagnetization curves of IRM shift toward higher fields (e.g., Bcr increases), and (iii) the FORC diagram shifts toward higher coercivity fields (e.g., Bc,FORC increases). For low-temperature results, compared to unoriented samples, the samples containing aligned chains have a much lower remanence loss of field-cooled (δFC) and zero-field-cooled (δZFC) remanence upon warming through the Verwey transition, higher δ-ratio (δ = δFC/δZFC) for the measurement parallel to the chain direction, and lower δ-ratio, larger δFC and δZFC values for the perpendicular measurement. Micromagnetic simulations confirm the experimental observations and reveal that the magnetization reversal of magnetosome chain appears to be noncoherent at low angles and coherent at high angles. The simulations also demonstrate that the angular dependence of magnetic properties is related to the dispersion degree of individual chains, indicating that effects of anisotropy need to be accounted for when using rock magnetism to identify magnetosomes or magnetofossils once they have been preserved in aligned chains. Additionally, this study experimentally demonstrates an empirical correspondence of the parameter Bc,FORC to Bcr rather than Bc, at least for magnetite chains with strong shape anisotropy. This suggests FORC analysis is a good discriminant of magnetofossils in sediments and rocks.

  1. Suppressing an anti-inflammatory cytokine reveals a strong age-dependent survival cost in mice.

    Directory of Open Access Journals (Sweden)

    Virginia Belloni

    Full Text Available BACKGROUND: The central paradigm of ecological immunology postulates that selection acts on immunity as to minimize its cost/benefit ratio. Costs of immunity may arise because the energetic requirements of the immune response divert resources that are no longer available for other vital functions. In addition to these resource-based costs, mis-directed or over-reacting immune responses can be particularly harmful for the host. In spite of the potential importance of immunopathology, most studies dealing with the evolution of the immune response have neglected such non resource-based costs. To keep the immune response under control, hosts have evolved regulatory pathways that should be considered when studying the target of the selection pressures acting on immunity. Indeed, variation in regulation may strongly modulate the negative outcome of immune activation, with potentially important fitness consequences. METHODOLOGY/PRINCIPAL FINDINGS: Here, we experimentally assessed the survival costs of reduced immune regulation by inhibiting an anti-inflammatory cytokine (IL-10 with anti-IL-10 receptor antibodies (anti-IL-10R in mice that were either exposed to a mild inflammation or kept as control. The experiment was performed on young (3 months and old (15 months individuals, as to further assess the age-dependent cost of suppressing immune regulation. IL-10 inhibition induced high mortality in old mice exposed to the mild inflammatory insult, whereas no mortality was observed in young mice. However, young mice experienced a transitory lost in body mass when injected with the anti-IL-10R antibodies, showing that the treatment was to a lesser extent also costly for young individuals. CONCLUSIONS: These results suggest a major role of immune regulation that deserves attention when investigating the evolution of immunity, and indicate that the capacity to down-regulate the inflammatory response is crucial for late survival and longevity.

  2. Strong invariance principles for sequential Bahadur--Kiefer and Vervaat error processes of long-range dependent sequences

    OpenAIRE

    Csörgő, Miklós; Szyszkowicz, Barbara; Wang, Lihong

    2006-01-01

    In this paper we study strong approximations (invariance principles) of the sequential uniform and general Bahadur--Kiefer processes of long-range dependent sequences. We also investigate the strong and weak asymptotic behavior of the sequential Vervaat process, that is, the integrated sequential Bahadur--Kiefer process, properly normalized, as well as that of its deviation from its limiting process, the so-called Vervaat error process. It is well known that the Bahadur--Kiefer and the Vervaa...

  3. Strong renormalization scheme dependence in τ-lepton decay: Fact or fiction?

    International Nuclear Information System (INIS)

    Chyla, J.

    1995-01-01

    The question of the renormalization scheme dependence of the τ semileptonic decay rate is examined in response to a recent criticism. Particular attention is payed to a distinction between a consistent quantitative description of this dependence and the actual selection of a subset of ''acceptable'' renormalization schemes. It is pointed out that this criticism is valid only within a particular definition of the ''strength'' of the renormalization scheme dependence and should not discourage further attempts to use the semileptonic τ decay rate for quantitative tests of perturbative QCD

  4. On local strong solutions to the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations with density-dependent viscosity and vacuum

    Science.gov (United States)

    Song, Sisi

    2018-04-01

    This paper concerns the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations with density-dependent viscosity and vacuum on Ω \\subset R^3. The domain Ω \\subset R^3 is a general connected smooth one, either bounded or unbounded. In particular, the initial density can have compact support when Ω is unbounded. First, we obtain the local existence and uniqueness of strong solution to the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations without any compatibility condition assumed on the initial data. Then, we also prove the continuous dependence of strong solution on the initial data under an additional compatibility condition.

  5. Spin dynamics and spin-dependent recombination of a polaron pair under a strong ac drive

    Science.gov (United States)

    Malla, Rajesh K.; Raikh, M. E.

    2017-08-01

    We study theoretically the recombination within a pair of two polarons in magnetic field subject to a strong linearly polarized ac drive. Strong drive implies that the Zeeman frequencies of the pair partners are much smaller than the Rabi frequency, so that the rotating wave approximation does not apply. What makes the recombination dynamics nontrivial is that the partners recombine only when they form a singlet S . By admixing singlet to triplets, the drive induces the triplet recombination as well. We calculate the effective decay rate of all four spin modes. Our main finding is that, under the strong drive, the major contribution to the decay of the modes comes from short time intervals when the driving field passes through zero. When the recombination time in the absence of drive is short, fast recombination from S leads to anomalously slow recombination from the other spin states of the pair. We show that, with strong drive, this recombination becomes even slower. The corresponding decay rate falls off as a power law with the amplitude of the drive.

  6. STRONG VELOCITY DEPENDENCE OF ELECTRON-CAPTURE IN COLLISIONS BETWEEN ALIGNED NA-ASTERISK(3P) AND HE-2+

    NARCIS (Netherlands)

    SCHLATMANN, AR; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE; PASCALE, J

    1993-01-01

    By analyzing spectra of emitted photons, we have studied state-selective electron capture in collisions of He2+ on aligned Na*(3p) atoms that span the ''velocity-matching'' energy between projectile and target electron. We find a strong dependence of the capture cross sections on the Na*(3p) orbital

  7. A note on the almost sure central limit theorems for the maxima of strongly dependent nonstationary Gaussian vector sequences

    Directory of Open Access Journals (Sweden)

    Xiang Zeng

    2016-06-01

    Full Text Available Abstract We prove some almost sure central limit theorems for the maxima of strongly dependent nonstationary Gaussian vector sequences under some mild conditions. The results extend the ASCLT to nonstationary Gaussian vector sequences and give substantial improvements for the weight sequence obtained by Lin et al. (Comput. Math. Appl. 62(2:635-640, 2011.

  8. Rapid Transition of the Hole Rashba Effect from Strong Field Dependence to Saturation in Semiconductor Nanowires.

    Science.gov (United States)

    Luo, Jun-Wei; Li, Shu-Shen; Zunger, Alex

    2017-09-22

    The electric field manipulation of the Rashba spin-orbit coupling effects provides a route to electrically control spins, constituting the foundation of the field of semiconductor spintronics. In general, the strength of the Rashba effects depends linearly on the applied electric field and is significant only for heavy-atom materials with large intrinsic spin-orbit interaction under high electric fields. Here, we illustrate in 1D semiconductor nanowires an anomalous field dependence of the hole (but not electron) Rashba effect (HRE). (i) At low fields, the strength of the HRE exhibits a steep increase with the field so that even low fields can be used for device switching. (ii) At higher fields, the HRE undergoes a rapid transition to saturation with a giant strength even for light-atom materials such as Si (exceeding 100 meV Å). (iii) The nanowire-size dependence of the saturation HRE is rather weak for light-atom Si, so size fluctuations would have a limited effect; this is a key requirement for scalability of Rashba-field-based spintronic devices. These three features offer Si nanowires as a promising platform for the realization of scalable complementary metal-oxide-semiconductor compatible spintronic devices.

  9. Laser based imaging of time depending microscopic scenes with strong light emission

    Science.gov (United States)

    Hahlweg, Cornelius; Wilhelm, Eugen; Rothe, Hendrik

    2011-10-01

    Investigating volume scatterometry methods based on short range LIDAR devices for non-static objects we achieved interesting results aside the intended micro-LIDAR: the high speed camera recording of the illuminated scene of an exploding wire -intended for Doppler LIDAR tests - delivered a very effective method of observing details of objects with extremely strong light emission. As a side effect a schlieren movie is gathered without any special effort. The fact that microscopic features of short time processes with high emission and material flow might be imaged without endangering valuable equipment makes this technique at least as interesting as the intended one. So we decided to present our results - including latest video and photo material - instead of a more theoretical paper on our progress concerning the primary goal.

  10. On Strong Positive Frequency Dependencies of Quality Factors in Local-Earthquake Seismic Studies

    Science.gov (United States)

    Morozov, Igor B.; Jhajhria, Atul; Deng, Wubing

    2018-03-01

    Many observations of seismic waves from local earthquakes are interpreted in terms of the frequency-dependent quality factor Q( f ) = Q0 f^{η } , where η is often close to or exceeds one. However, such steep positive frequency dependencies of Q require careful analysis with regard to their physical consistency. In particular, the case of η = 1 corresponds to frequency-independent (elastic) amplitude decays with time and consequently requires no Q-type attenuation mechanisms. For η > 1, several problems with physical meanings of such Q-factors occur. First, contrary to the key premise of seismic attenuation, high-frequency parts of the wavefield are enhanced with increasing propagation times relative to the low-frequency ones. Second, such attenuation cannot be implemented by mechanical models of wave-propagating media. Third, with η > 1, the velocity dispersion associated with such Q(f) occurs over unrealistically short frequency range and has an unexpected oscillatory shape. Cases η = 1 and η > 1 are usually attributed to scattering; however, this scattering must exhibit fortuitous tuning into the observation frequency band, which appears unlikely. The reason for the above problems is that the inferred Q values are affected by the conventional single-station measurement procedure. Both parameters Q 0 and are apparent, i.e., dependent on the selected parameterization and inversion method, and they should not be directly attributed to the subsurface. For η ≈ 1, parameter Q 0 actually describes the frequency-independent amplitude decay in access of some assumed geometric spreading t -α , where α is usually taken equal one. The case η > 1 is not allowed physically and could serve as an indicator of problematic interpretations. Although the case 0 < η < 1 is possible, its parameters Q 0 and may also be biased by the measurement procedure. To avoid such difficulties of Q-based approaches, we recommend measuring and interpreting the amplitude-decay rates

  11. Relationships of the Leadership Attitudes and Beliefs Scale with Student Types, Study Habits, Life-Long Learning, and GPA

    Science.gov (United States)

    Wielkiewicz, Richard M.; Prom, Christina L.; Loos, Steven

    2005-01-01

    The Leadership Attitudes and Beliefs Scale (LABS-III; Wielkiewicz, 2000) was validated against a measure with a more traditional, position-based definition of leadership. Disagreement with Hierarchical Thinking was associated with a higher GPA. A Life-Long Learning scale was strongly associated with GPA, Systemic Thinking, and social activism.…

  12. Orientation dependent slip and twinning during compression and tension of strongly textured magnesium AZ31 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Al-Samman, T., E-mail: al-samman@imm.rwth-aachen.de [Institut fuer Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, D-52064 Aachen (Germany); Li, X. [Institut fuer Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, D-52064 Aachen (Germany); Chowdhury, S. Ghosh [CSIR National Metallurgical Laboratory, MST Division, Jamshedpur 831007 (India)

    2010-06-15

    Over recent years there have been a remarkable number of studies dealing with compression of magnesium. A literature search, however, shows a noticeably less number of papers concerned with tension and a very few papers comparing both modes, systematically, in one study. The current investigation reports the anisotropic deformation behavior and concomitant texture and microstructure evolution investigated in uniaxial tension and compression tests in two sample directions performed on an extruded commercial magnesium alloy AZ31 at different Z conditions. For specimens with the loading direction parallel to the extrusion axis, the tension-compression strength anisotropy was pronounced at high Z conditions. Loading at 45{sup o} from the extrusion axis yielded a tension-compression strength behavior that was close to isotropic. During tensile loading along the extrusion direction the extrusion texture resists twinning and favors prismatic slip (contrary to compression). This renders the shape change maximum in the basal plane and equal to zero along the c-axis, which resulted in the orientation of individual grains remaining virtually intact during all tension tests at different Z conditions. For the other investigated sample direction, straining was accommodated along the c-axis, which was associated with a lattice rotation, and thus, a change of crystal orientation. Uniaxial compression at a low Z condition (400 deg. C/10{sup -4} s{sup -1}) yielded a desired texture degeneration, which was explained on the basis of a more homogeneous partitioning of slip systems that reduces anisotropy and enhanced dynamic recrystallization (DRX), which counteracts the strong deformation texture. The critical strains for the nucleation of DRX in tensiled specimens at the highest investigated Z condition (200 deg. C/10{sup -2} s{sup -1}) were found to range between 4% and 5.6%.

  13. Tunable photonic crystal for THz radiation in layered superconductors: Strong magnetic-field dependence of the transmission coefficient

    International Nuclear Information System (INIS)

    Savel'ev, Sergey; Rakhmanov, A.L.; Nori, Franco

    2006-01-01

    Josephson plasma waves are scattered by the Josephson vortex lattice. This scattering results in a strong dependence, on the in-plane magnetic-field H ab , of the reflection and transmission of THz radiation propagating in layered superconductors. In particular, a tunable band-gap structure (THz photonic crystal) occurs in such a medium. These effects can be used, by varying H ab , for the selective frequency-filtering of THz radiation

  14. PROLARM: Cancer risk from medical diagnostic exposures is strongly dependent upon patients' prognosis

    International Nuclear Information System (INIS)

    Eschner, Wolfgang; Schmidt, Matthias; Dietlein, Markus; Schicha, Harald

    2008-01-01

    Full text: Purpose: a) To evaluate the impact of the reduced life expectancy of patients (compared to a non-patient group with same age distribution) on their risk of developing cancer from the diagnostic use of radiation. b) To find an approximation to such reduction in risk which depends only on the patient's age, a, and his life expectancy, but is independent of the choice of values for the baseline risk of cancer incidence, m(a), and the enhanced relative risk ERR(a) from radiation exposure. Method: The lifetime attributable risk LAR (of a radiation-induced malignancy to manifest itself) is a function of age at exposure, e, and given by integrating over attained age, a, the product of ERR(a), baseline cancer risk m(a) and the relative probability of surviving to age a, S'(a,e). We define a 'prognosis-based LAR modifier' (PROLARM) as the ratio of risks for non-patient, LAR(a), and patient, LAR p (a), a dimensionless quantity that gives a measure of reduction of LAR due to the patient's prognosis. With the survival of the patient group, S p ' (a,e), and for any choice of fitted function for ERR(a) like those used in BEIR VII report, PROLARM ≥∫d'(a,e) da/∫S p '(a,e) da, i.e. the ratio of the survival integrals gives a lower (thus conservative) estimate of the reduction in risk. Results: The method was applied to n=4285 patients with metastatic breast cancer for whom survival as a function of age at metastasis was known. Figure shows that LAR is decreased significantly for all ages at exposure. At younger ages, this decrease is more pronounced (PROLARM ≥ 20 for e ≤ 65). Example: using ERR values of BEIR VII, the LAR due to 10 mSv effective dose at age a = 50 would drop from 1.2 E-3 for non-patient to 4.3E-5 for a patient, i.e. by a factor (PROLARM) of 29. Using only survival data, that factor is 27 (but no LAR can be computed). In other words: 10 mSv for a patient correspond risk-wise to 0.4 mSv for non-patient. The method can be applied to any pathology

  15. Strength of fayalite up to 8.5 GPa

    Science.gov (United States)

    Guignard, J.; Bystricky, M.; Béjina, F.; Crichton, W. A.; Proietti, A.; Tercé, N.

    2017-06-01

    A dense polycrystalline aggregate of synthetic fayalite (Fe2SiO4) was deformed up to 8.5 GPa at room temperature in the D-DIA press installed at the European Synchrotron Radiation Facility beamline ID06. Five successive shortening-lengthening cycles were performed at different pressures and up to a final strain of approximately 25% at a typical strain rate of about 10-5 s-1. Lattice stresses were quantified from ( hkl) reflections accessible with a 55-keV monochromatic beam. Combined stress and strain data show that during each cycle, fayalite deforms elastically before yielding at an axial strain close to 2%. This yielding occurs at a macroscopic stress (taken as the average of the estimated lattice stresses) of 1.5-2 GPa, irrespective of pressure. Very moderate stress hardening takes place beyond the yield point, and the average stress becomes almost constant after a strain of 5-6%, suggesting a low-temperature plastic regime. Lattice stresses estimated with (131), (130), and (022) reflections are always higher than stresses estimated with (111) and (112) by a factor of about 1.5. In addition, the (131) lattice stress becomes progressively lower than the (130) and (022) lattice stresses with increasing pressure, which suggests a possible change in dominant slip systems around 5-6 GPa. Combining our results with data from Chen et al. (Phys Earth Planet Inter 143-144:347-356, (2004), we determined a low-temperature plasticity flow law with an activation energy of 217 ± 25 kJ mol-1 and a Peierls stress at 0 GPa, σ p0 = 3.92 ± 0.02 GPa, that is consistent with dislocation motion being limited by discrete obstacles. The pressure dependence is almost entirely accounted for by the Peierls stress, with d σ p/d P = G'/ G 0, where G' is the derivative of G 0, the shear modulus. Our results suggest that fayalite has a smaller pressure dependence of low-temperature plasticity than (Mg0.9Fe0.1)2SiO4 and that the transition between low-temperature plasticity and high

  16. IMPACT OF COMPUTER GAMES ON STUDENTS GPA

    OpenAIRE

    Karzan Wakil; Shano Omer; Bayan Omer

    2017-01-01

    The computer game industry has flourished to become the world’s largest entertainment, one of the problem students playing with electronic games for long time without thinking about negative affections especially on their GPA. In this paper to present impact of computer games on creativity and academic achievement of basic school students, we proposed a questionnaires form for 100 students at basic schools. The result of our research explained that the students playing between 1-3 hours per d...

  17. Prediction of strong acceleration motion depended on focal mechanism; Shingen mechanism wo koryoshita jishindo yosoku ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kaneda, Y.; Ejiri, J. [Obayashi Corp., Tokyo (Japan)

    1996-10-01

    This paper describes simulation results of strong acceleration motion with varying uncertain fault parameters mainly for a fault model of Hyogo-ken Nanbu earthquake. For the analysis, based on the fault parameters, the strong acceleration motion was simulated using the radiation patterns and the breaking time difference of composite faults as parameters. A statistic waveform composition method was used for the simulation. For the theoretical radiation patterns, directivity was emphasized which depended on the strike of faults, and the maximum acceleration was more than 220 gal. While, for the homogeneous radiation patterns, the maximum accelerations were isotopically distributed around the fault as a center. For variations in the maximum acceleration and the predominant frequency due to the breaking time difference of three faults, the response spectral value of maximum/minimum was about 1.7 times. From the viewpoint of seismic disaster prevention, underground structures including potential faults and non-arranging properties can be grasped using this simulation. Significance of the prediction of strong acceleration motion was also provided through this simulation using uncertain factors, such as breaking time of composite faults, as parameters. 4 refs., 4 figs., 1 tab.

  18. SNP rs16969968 as a Strong Predictor of Nicotine Dependence and Lung Cancer Risk in a North Indian Population

    Science.gov (United States)

    Pandey, Namita; Pal, Soumyadip; Sharma, Lokesh Kumar; Guleria, Randeep; Mohan, Anant; Srivastava, Tapasya

    2017-01-01

    Background: The 15q24-25 loci contain genes (CHRNA5 and CHRNA3) encoding nicotinic acetylcholine receptor subunits. We here determined for the first time the association of genetic variants rs16969968 and rs3743074 in CHRNA5 and CHRNA3, respectively, on nicotine dependence and lung cancer risk in a North Indian population by a case-control approach. Methods: Venous blood samples were obtained from 324 participants (108 lung cancer patients and 216 healthy individuals). DNA was extracted and PCR amplified with primers flanking the SNPs rs16969968 and rs3743074. Amplicons were subjected to sequencing and logistic regression was used to analyze association between variables. Results: The risk variant SNP rs16969968 in both heterozygous and homozygous forms appeared to exert a significant effect on nicotine dependence [GA (OR=2.77) and AA (OR=2.53)]. As expected, smoking was strongly associated with lung cancer (OR= 2.62). Risk allele rs16969968 in CHRNA5 also showed a significant association with increased lung cancer risk in our cohort, alone (OR= 4.99) and with smoking as a co-variable (OR= 4.28). Comparison of our analysis with other populations suggested that individuals with rs16969968 risk allele in the Indian population are more susceptible to lung cancer. Conclusion: Overall, the results strongly indicated that, in our cohort North Indian population, the genetic variant rs16969968, but not rs3743074, is significantly associated with both nicotine dependence and increased risk of lung cancer. While the results are significant, there is further need to increase the sample size and improve precision of our risk prediction. PMID:29172281

  19. HbA1c as the diagnostic criterion for diabetes reduces incidence and prevalence of DM2 by 25% but strongly depending on analytical quality

    DEFF Research Database (Denmark)

    Brandslund, Ivan; Nielsen, Aneta Aleksandra; Hyldtoft Petersen, Per

    HbA1c as the diagnostic criterion for diabetes reduces incidence and prevalence of DM2 by 25% but strongly depending on analytical quality......HbA1c as the diagnostic criterion for diabetes reduces incidence and prevalence of DM2 by 25% but strongly depending on analytical quality...

  20. He 2++ molecular ion in a strong time-dependent magnetic field: a current-density functional study.

    Science.gov (United States)

    Vikas

    2011-08-01

    The He 2++ molecular ion exposed to a strong ultrashort time-dependent (TD) magnetic field of the order of 10(9) G is investigated through a quantum fluid dynamics (QFD) and current-density functional theory (CDFT) based approach using vector exchange-correlation (XC) potential and energy density functional that depend not only on the electronic charge-density but also on the current density. The TD-QFD-CDFT computations are performed in a parallel internuclear-axis and magnetic field-axis configuration at the field-free equilibrium internuclear separation R = 1.3 au with the field-strength varying between 0 and 10(11) G. The TD behavior of the exchange- and correlation energy of the He 2++ is analyzed and compared with that obtained using a [B-TD-QFD-density functional theory (DFT)] approach based on the conventional TD-DFT under similar computational constraints but using only scalar XC potential and energy density functional dependent on the electronic charge-density alone. The CDFT based approach yields TD exchange- and correlation energy and TD electronic charge-density significantly different from that obtained using the conventional TD-DFT based approach, particularly, at typical magnetic field strengths and during a typical time period of the TD field. This peculiar behavior of the CDFT-based approach is traced to the TD current-density dependent vector XC potential, which can induce nonadiabatic effects causing retardation of the oscillating electronic charge density. Such dissipative electron dynamics of the He 2++ molecular ion is elucidated by treating electronic charge density as an electron-"fluid" in the terminology of QFD. Copyright © 2011 Wiley Periodicals, Inc.

  1. Noise-induced extinction for a ratio-dependent predator-prey model with strong Allee effect in prey

    Science.gov (United States)

    Mandal, Partha Sarathi

    2018-04-01

    In this paper, we study a stochastically forced ratio-dependent predator-prey model with strong Allee effect in prey population. In the deterministic case, we show that the model exhibits the stable interior equilibrium point or limit cycle corresponding to the co-existence of both species. We investigate a probabilistic mechanism of the noise-induced extinction in a zone of stable interior equilibrium point. Computational methods based on the stochastic sensitivity function technique are applied for the analysis of the dispersion of random states near stable interior equilibrium point. This method allows to construct a confidence domain and estimate the threshold value of the noise intensity for a transition from the coexistence to the extinction.

  2. Size-dependent Young’s modulus in ZnO nanowires with strong surface atomic bonds

    Science.gov (United States)

    Fan, Shiwen; Bi, Sheng; Li, Qikun; Guo, Qinglei; Liu, Junshan; Ouyang, Zhongliang; Jiang, Chengming; Song, Jinhui

    2018-03-01

    The mechanical properties of size-dependent nanowires are important in nano-electro-mechanical systems (NEMSs), and have attracted much research interest. Characterization of the size effect of nanowires in atmosphere directly to broaden their practical application instead of just in high vacuum situations, as reported previously, is desperately needed. In this study, we systematically studied the Young’s modulus of vertical ZnO nanowires in atmosphere. The diameters ranged from 48 nm to 239 nm with a resonance method using non-contact atomic force microscopy. The values of Young’s modulus in atmosphere present extremely strong increasing tendency with decreasing diameter of nanowire due to stronger surface atomic bonds compared with that in vacuum. A core-shell model for nanowires is proposed to explore the Young’s modulus enhancement in atmosphere, which is correlated with atoms of oxygen occurring near the nanowire surface. The modified model is more accurate for analyzing the mechanical behavior of nanowires in atmosphere compared with the model in vacuum. Furthermore, it is possible to use this characterization method to measure the size-related elastic properties of similar wire-sharp nanomaterials in atmosphere and estimate the corresponding mechanical behavior. The study of the size-dependent Young’s modulus in ZnO nanowires in atmosphere will improve the understanding of the mechanical properties of nanomaterials as well as providing guidance for applications in NEMSs, nanogenerators, biosensors and other related areas.

  3. DEFLAGRATION RATES OF SECONDARY EXPLOSIVES UNDER STATIC MPA - GPA PRESSURE

    Energy Technology Data Exchange (ETDEWEB)

    Zaug, J; Young, C; Long, G; Maienschein, J; Glascoe, E; Hansen, D; Wardell, J; Black, C; Sykora, G

    2009-07-30

    We provide measurements of the chemical reaction propagation rate (RPR) as a function of pressure using diamond anvil cell (DAC) and strand burner technologies. Materials investigated include HMX and RDX crystalline powders, LX-04 (85% HMX and 15% Viton A), and Composition B (63% RDX, 36% TNT, 1% wax). The anomalous correspondence between crystal structure, including in some instances isostructural phase transitions, on pressure dependent RPRs of HMX and RDX are correlated to confocal micro-Raman spectroscopic results. The contrast between DAC GPa and strand burner MPa regime measurements yield insight into explosive material burn phenomena. Here we highlight pressure dependent physicochemical mechanisms that appear to affect the deflagration rate of precompressed energetic materials.

  4. Room-temperature vibrational properties of potassium gadolinium double tungstate under compression up to 32 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Física Aplicada – ICMUV, Universitat de València, 46100 Burjassot, Valencia (Spain); Pellicer-Porres, J. [Departamento de Física Aplicada – ICMUV, Universitat de València, 46100 Burjassot, Valencia (Spain); Pujol, M.C.; Carvajal, J.J.; Aguiló, M. [Física i Cristal lografia de Materials i Nanomaterials (FiCMA-FICNA) – EMAS, Universitat Rovira i Virgili (URV), C/Marcel lí Domingo 1, 43005 Tarragona (Spain)

    2015-07-25

    Highlights: • Two phase transitions are pressure-induced in KGd(WO{sub 4}){sub 2} at 7.2, and 14.2 GPa. • Raman-active modes and their pressure dependences are reported and discussed. • Several modes showing a weak softening are found and related with structural changes. - Abstract: KGd(WO{sub 4}){sub 2} has been studied by high-pressure Raman spectroscopy at room temperature up to 32.2 GPa. Evidences of two pressure-driven phase transitions have been detected. The low-pressure monoclinic phase undergoes a phase transition at 7.2(±0.9) GPa. The second transition is found at 14.2(±1.6) GPa. Both transitions are reversible. No evidence of pressure-induced amorphization is found up to 32 GPa. The pressure dependence of the Raman active modes of the low- and high-pressure phases is reported. A Raman mode is detected to exhibit a weak softening in the low-pressure phase. Three Raman modes are also observed to have a similar behavior in the second high-pressure phase. The reported results are discussed comparing with the studies available in related tungstates. Emphasis is placed on the physical implications of the results.

  5. Fitness Effects of Chlorpyrifos in the Damselfly Enallagma cyathigerum Strongly Depend upon Temperature and Food Level and Can Bridge Metamorphosis.

    Directory of Open Access Journals (Sweden)

    Lizanne Janssens

    Full Text Available Interactions between pollutants and suboptimal environmental conditions can have severe consequences for the toxicity of pollutants, yet are still poorly understood. To identify patterns across environmental conditions and across fitness-related variables we exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos at two food levels or at two temperatures and quantified four fitness-related variables (larval survival, development time, mass at emergence and adult cold resistance. Food level and temperature did not affect survival in the absence of the pesticide, yet the pesticide reduced survival only at the high temperature. Animals reacted to the pesticide by accelerating their development but only at the high food level and at the low temperature; at the low food level, however, pesticide exposure resulted in a slower development. Chlorpyrifos exposure resulted in smaller adults except in animals reared at the high food level. Animals reared at the low food level and at the low temperature had a higher cold resistance which was not affected by the pesticide. In summary our study highlight that combined effects of exposure to chlorpyrifos and the two environmental conditions (i were mostly interactive and sometimes even reversed in comparison with the effect of the environmental condition in isolation, (ii strongly differed depending on the fitness-related variable under study, (iii were not always predictable based on the effect of the environmental condition in isolation, and (iv bridged metamorphosis depending on which environmental condition was combined with the pesticide thereby potentially carrying over from aquatic to terrestrial ecosystems. These findings are relevant when extrapolating results of laboratory tests done under ideal environmental conditions to natural communities.

  6. Mycolactone-Dependent Depletion of Endothelial Cell Thrombomodulin Is Strongly Associated with Fibrin Deposition in Buruli Ulcer Lesions.

    Directory of Open Access Journals (Sweden)

    Joy Ogbechi

    2015-07-01

    Full Text Available A well-known histopathological feature of diseased skin in Buruli ulcer (BU is coagulative necrosis caused by the Mycobacterium ulcerans macrolide exotoxin mycolactone. Since the underlying mechanism is not known, we have investigated the effect of mycolactone on endothelial cells, focussing on the expression of surface anticoagulant molecules involved in the protein C anticoagulant pathway. Congenital deficiencies in this natural anticoagulant pathway are known to induce thrombotic complications such as purpura fulimans and spontaneous necrosis. Mycolactone profoundly decreased thrombomodulin (TM expression on the surface of human dermal microvascular endothelial cells (HDMVEC at doses as low as 2 ng/ml and as early as 8 hrs after exposure. TM activates protein C by altering thrombin's substrate specificity, and exposure of HDMVEC to mycolactone for 24 hours resulted in an almost complete loss of the cells' ability to produce activated protein C. Loss of TM was shown to be due to a previously described mechanism involving mycolactone-dependent blockade of Sec61 translocation that results in proteasome-dependent degradation of newly synthesised ER-transiting proteins. Indeed, depletion from cells determined by live-cell imaging of cells stably expressing a recombinant TM-GFP fusion protein occurred at the known turnover rate. In order to determine the relevance of these findings to BU disease, immunohistochemistry of punch biopsies from 40 BU lesions (31 ulcers, nine plaques was performed. TM abundance was profoundly reduced in the subcutis of 78% of biopsies. Furthermore, it was confirmed that fibrin deposition is a common feature of BU lesions, particularly in the necrotic areas. These findings indicate that there is decreased ability to control thrombin generation in BU skin. Mycolactone's effects on normal endothelial cell function, including its ability to activate the protein C anticoagulant pathway are strongly associated with this

  7. Comparing the epidermal growth factor interaction with four different cell lines: intriguing effects imply strong dependency of cellular context.

    Directory of Open Access Journals (Sweden)

    Hanna Björkelund

    Full Text Available The interaction of the epidermal growth factor (EGF with its receptor (EGFR is known to be complex, and the common over-expression of EGF receptor family members in a multitude of tumors makes it important to decipher this interaction and the following signaling pathways. We have investigated the affinity and kinetics of (125I-EGF binding to EGFR in four human tumor cell lines, each using four culturing conditions, in real time by use of LigandTracer®.Highly repeatable and precise measurements show that the overall apparent affinity of the (125I-EGF - EGFR interaction is greatly dependent on cell line at normal culturing conditions, ranging from K(D ≈ 200 pM on SKBR3 cells to K(D≈8 nM on A431 cells. The (125I-EGF - EGFR binding curves (irrespective of cell line have strong signs of multiple simultaneous interactions. Furthermore, for the cell lines A431 and SKOV3, gefitinib treatment increases the (125I-EGF - EGFR affinity, in particular when the cells are starved. The (125I-EGF - EGFR interaction on cell line U343 is sensitive to starvation while as on SKBR3 it is insensitive to gefitinib and starvation.The intriguing pattern of the binding characteristics proves that the cellular context is important when deciphering how EGF interacts with EGFR. From a general perspective, care is advisable when generalizing ligand-receptor interaction results across multiple cell-lines.

  8. Strong Dependence of U.S. Summertime Air Quality on the Decadal Variability of Atlantic Sea Surface Temperatures

    Science.gov (United States)

    Shen, Lu; Mickley, Loretta J.; Leibensperger, Eric M.; Li, Mingwei

    2017-12-01

    We find that summertime air quality in the eastern U.S. displays strong dependence on North Atlantic sea surface temperatures, resulting from large-scale ocean-atmosphere interactions. Using observations, reanalysis data sets, and climate model simulations, we further identify a multidecadal variability in surface air quality driven by the Atlantic Multidecadal Oscillation (AMO). In one-half cycle ( 35 years) of the AMO from cold to warm phase, summertime maximum daily 8 h ozone concentrations increase by 1-4 ppbv and PM2.5 concentrations increase by 0.3-1.0 μg m-3 over much of the east. These air quality changes are related to warmer, drier, and more stagnant weather in the AMO warm phase, together with anomalous circulation patterns at the surface and aloft. If the AMO shifts to the cold phase in future years, it could partly offset the climate penalty on U.S. air quality brought by global warming, an effect which should be considered in long-term air quality planning.

  9. Magnetic-field dependence of strongly anisotropic spin reorientation transition in NdFeO3: a terahertz study.

    Science.gov (United States)

    Jiang, Junjie; Song, Gaibei; Wang, Dongyang; Jin, Zuanming; Tian, Zhen; Lin, Xian; Han, Jiaguang; Ma, Guohong; Cao, Shixun; Cheng, Zhenxiang

    2016-03-23

    One of the biggest challenges in spintronics is finding how to switch the magnetization of a material. One way of the spin switching is the spin reorientation transition (SRT), a switching of macroscopic magnetization rotated by 90°. The macroscopic magnetization in a NdFeO3 single crystal rotates from Γ4 to Γ2 via Γ24 as the temperature is decreased from 170 to 100 K, while it can be switched back to Γ4 again by increasing the temperature. However, the precise roles of the magnetic-field induced SRT are still unclear. By using terahertz time-domain spectroscopy (THz-TDS), here, we show that the magnetic-field induced SRT between Γ4 and Γ2 is strongly anisotropic, depending on the direction of the applied magnetic field. Our experimental results are well interpreted by the anisotropy of rare-earth Nd(3+) ion. Furthermore, we find that the critical magnetic-field required for SRT can be modified by changing the temperature. Our study suggests that the anisotropic SRT in NdFeO3 single crystal provides a platform to facilitate the potential applications in robust spin memory devices.

  10. Predicting Success Study Using Students GPA Category

    Directory of Open Access Journals (Sweden)

    Awan Setiawan

    2015-06-01

    Full Text Available Abstract. Maintaining student graduation rates are the main tasks of a University. High rates of student graduation and the quality of graduates is a success indicator of a university, which will have an impact on public confidence as stakeholders of higher education and the National Accreditation Board as a regulator (government. Making predictions of student graduation and determine the factors that hinders will be a valuable input for University. Data mining system facilitates the University to create the segmentation of students’ performance and prediction of their graduation. Segmentation of student by their performance can be classified in a quadrant chart is divided into 4 segments based on grade point average and the growth rate of students performance index per semester. Standard methodology in data mining i.e CRISP-DM (Cross Industry Standard Procedure for Data Mining will be implemented in this research. Making predictions, graduation can be done through the modeling process by utilizing the college database. Some algorithms such as C5, C & R Tree, CHAID, and Logistic Regression tested in order to find the best model. This research utilizes student performance data for several classes. Parameters used in addition to GPA also included the master's students data are expected to build the student profile data. The outcome of the study is the student category based on their study performance and prediction of graduation. Based on this prediction, the university may recommend actions to be taken to improve the student achievement index and graduation rates. Keywords: graduation, segmentation, quadrant GPA, data mining, modeling algorithms

  11. Predicting Success Study Using Students GPA Category

    Directory of Open Access Journals (Sweden)

    Awan Setiawan

    2015-07-01

    Full Text Available Abstract. Maintaining student graduation rates are the main tasks of a University. High rates of student graduation and the quality of graduates is a success indicator of a university, which will have an impact on public confidence as stakeholders of higher education and the National Accreditation Board as a regulator (government. Making predictions of student graduation and determine the factors that hinders will be a valuable input for University. Data mining system facilitates the University to create the segmentation of students’ performance and prediction of their graduation. Segmentation of student by their performance can be classified in a quadrant chart is divided into 4 segments based on grade point average and the growth rate of students performance index per semester. Standard methodology in data mining i.e CRISP-DM (Cross Industry Standard Procedure for Data Mining will be implemented in this research. Making predictions, graduation can be done through the modeling process by utilizing the college database. Some algorithms such as C5, C & R Tree, CHAID, and Logistic Regression tested in order to find the best model. This research utilizes student performance data for several classes. Parameters used in addition to GPA also included the master's students data are expected to build the student profile data. The outcome of the study is the student category based on their study performance and prediction of graduation. Based on this prediction, the  university may recommend actions to be taken to improve the student  achievement index and graduation rates.Keywords: graduation, segmentation, quadrant GPA, data mining, modeling algorithms

  12. Phase transitions in cerium at high pressure up to 15 GPa and at high temperatures

    International Nuclear Information System (INIS)

    Tsiok, O.B.; Khvostantsev, L.G.

    2001-01-01

    The phase transitions in cerium are studied through the electric resistance measurement method at pressures up to 15 GPa and high temperatures. It is determined that cerium at pressures above 10 GPa constitutes the mixture of stable and metastable phases, whereby its composition depends on thee trajectory on the P-T-plane, leading to the point with the given P-T-parameters. The transitions in the stable and metastable components of this mixture, proceeding more or less independently, demonstrate the entangled picture of the phase transitions. It was supposed that only the α (Fcc) and α' (α-U) phases are stable in the area of pressures above the well-known γ-α-transition; the remainder phases are metastable. The proposed cupola-shaped equilibrium phase diagram includes extremely wide hysteresis area, wherein the stable and metastable phases may coexist. However after heating above 500 deg C at 15 GPa there remains only one phase α (Fcc) [ru

  13. About angular dependence of intensity of absent-minded radiation in approach of the strong dissipation of colliding ionic-sound waves

    International Nuclear Information System (INIS)

    Solikhov, D.K.

    2015-01-01

    Present article is devoted to angular dependence of intensity of absent-minded radiation in approach of the strong dissipation of colliding ionic-sound waves. The operation angular dependence of dimensionless of intensity of absent-minded radiation in two-dimensional field of localisation of a wave of a rating in approach of the strong dissipation of passers is ionic-sound waves is viewed. (author)

  14. Feasibility of in situ neutron diffraction studies of non-crystalline silicates up to pressures of 25 GPa

    International Nuclear Information System (INIS)

    Wilding, Martin; Guthrie, Malcolm; Bull, Craig L; Tucker, Matt G; McMillan, Paul F

    2008-01-01

    There is an increasing interest in the structural modifications found in liquids and amorphous systems as a function of pressure. Neutron diffraction is a key technique for determining these structures, but its application in high pressure studies remains in its infancy. Recent developments now permit in situ neutron scattering studies of amorphous materials to very high pressure conditions. Here we present new data for MgO-SiO 2 and SiO 2 glasses collected at up to 8.6 and 24 GPa respectively, using two distinct high pressure anvil geometries. The data collected on the MgO-SiO 2 system appear to be reliable, and suggest strong changes in the chemical ordering. In contrast, the higher pressure SiO 2 data highlight significant difficulties in performing appropriate corrections for pressure-dependent background and attenuation effects. These challenges are discussed, and future improvements to the technique are proposed

  15. Investigating the Utility of a GPA Institutional Adjustment Index

    Science.gov (United States)

    Didier, Thomas; Kreiter, Clarence D.; Buri, Russell; Solow, Catherine

    2006-01-01

    Background: Grading standards vary widely across undergraduate institutions. If, during the medical school admissions process, GPA is considered without reference to the institution attended, it will disadvantage applicants from undergraduate institutions employing rigorous grading standards. Method: A regression-based GPA institutional equating…

  16. Ellipticity dependence of the near-threshold harmonics of H2 in an elliptical strong laser field.

    Science.gov (United States)

    Yang, Hua; Liu, Peng; Li, Ruxin; Xu, Zhizhan

    2013-11-18

    We study the ellipticity dependence of the near-threshold (NT) harmonics of pre-aligned H2 molecules using the time-dependent density functional theory. The anomalous maximum appearing at a non-zero ellipticity for the generated NT harmonics can be attributed to multiphoton effects of the orthogonally polarized component of the elliptical driving laser field. Our calculation also shows that the structure of the bound-state, such as molecular alignment and bond length, can be sensitively reflected on the ellipticity dependence of the near-threshold harmonics.

  17. A reversible pressure-induced phase transition in β-glycine at 0.76 GPa

    International Nuclear Information System (INIS)

    Goryainov, S.V.; Kolesnik, E.N.; Boldyreva, E.V.

    2005-01-01

    Single crystals of β-glycine were studied at pressures up to 7.6 GPa in a diamond anvil cell (DAC) in situ by Raman spectroscopy and polarized optical microscopy. A reversible phase transition was observed at 0.76 GPa. A boundary between the two phases could be observed in the microscope if the phase transition was slow enough. The phase transition was accompanied by cracking of the crystal. The birefringence in the high-pressure phase 2 was close to that in the starting phase 1, so that the phase transition can be supposed to preserve the monoclinic crystal system. Every vibrational band in the spectrum of the high-pressure phase can be related to a corresponding band in the starting phase, excluding lattice vibrations. The frequencies of most vibrations changed by a jump at the transition point. Low-frequency lattice modes showed linear pressure dependence when pressure increased from 0.76 to 7.6 GPa. This can be a manifestation of the softening of the libration modes of glycine at the phase transition point. At high pressures (in the range of 6.5-7.6 GPa) the shifts of the frequencies of some vibrational bands were nonlinear. This can be related to the rotations and twisting of the zwitter-ions of glycine

  18. On the model dependence of the determination of the strong coupling constant in second order QCD from e+e--annihilation into hadrons

    International Nuclear Information System (INIS)

    Achterberg, O.; D'Agostini, G.; Apel, W.D.; Engler, J.; Fluegge, G.; Forstbauer, B.; Fries, D.C.; Fues, W.; Gamerdinger, K.; Henkes, T.; Hopp, G.; Krueger, M.; Kuester, H.; Mueller, H.; Randoll, H.; Schmidt, G.; Schneider, H.; Boer, W. de; Buschhorn, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kruse, U.; Lierl, H.; Lueers, D.; Oberlack, H.; Schacht, P.; Bonneaud, G.; Colas, P.; Cordier, A.; Davier, M.; Fournier, D.; Grivaz, J.F.; Haissinski, J.; Journe, V.; Laplanche, F.; Le Diberder, F.; Mallik, U.; Ros, E.; Veillet, J.J.; Behrend, H.J.; Fenner, H.; Schachter, M.J.; Schroeder, V.; Sindt, H.

    1983-12-01

    Hadronic events obtained with the CELLO detector at PETRA are compared with second order QCD predictions using different models for the fragmentation of quarks and gluons into hadrons. We find that the model dependence in the determination of the strong coupling constant persists when going from first to second order QCD calculations. (orig.)

  19. Equation of State of Triaminotrinitrobenzene (TATB) up to 75 GPa

    Science.gov (United States)

    Chellappa, Raja; Dattelbaum, Dana

    2015-06-01

    The energetic properties of triaminotrinitrobenzene (TATB) combined with its insensitivity makes it an attractive candidate for advanced munition applications. Understanding the effect of pressure (P) and temperature (T) on structure-property relationship of TATB and measurement of thermodynamic quantities (bulk modulus and its derivative, Grüneisen coefficient, and others) is essential for high level predictive modeling. The P-V isotherm for TATB is currently available only up to 13 GPa. In this work, synchrotron XRD measurements on TATB powder under hydrostatic conditions (Ne medium) were performed up to 75 GPa and we will present a revision of equation of state and discuss evidence for phase transformations at ~ 30 GPa and ~ 60 GPa based on these new measurements.

  20. Strong dependence of rain-induced lidar depolarization on the illumination angle: experimental evidence and geometrical-optics interpretation.

    Science.gov (United States)

    Roy, G; Bissonnette, L R

    2001-09-20

    Backscatter and depolarization lidar measurements from clouds and precipitation are reported as functions of the elevation angle of the pointing lidar direction. We recorded the data by scanning the lidar beam (Nd:YAG) at a constant angular speed of ~3.5 degrees /s while operating at a repetition rate of 10 Hz. We show that in rain there is an evident and at times spectacular dependence on the elevation angle. That dependence appears to be sensitive to raindrop size. We have developed a three-dimensional polarization-dependent ray-tracing algorithm to calculate the backscatter and the depolarization ratio by large nonspherical droplets. We have applied it to raindrop shapes derived from existing static and dynamic (oscillating) models. We show that many of the observed complex backscatter and depolarization features can be interpreted to a good extent by geometrical optics. These results suggest that there is a definite need for more extensive calculations of the scattering phase matrix elements for large deformed raindrops as functions of the direction of illumination. Obvious applications are retrieval of information on the liquid-solid phase of precipitation and on the size and the vibration state of raindrops.

  1. Calculated Phase Relations in the System KFMASH Between 6 and 16 GPa

    Science.gov (United States)

    Massonne, H.; Brandelik, A.

    2005-12-01

    To better understand the modal compositions of deeply buried metagranitoids and metapelites, phase relations in the model system K2O-FeO-MgO-Al2O3-SiO2-H2O (KFMASH) with SiO2 in excess were calculated applying thermodynamic principles. We used the software package PTGIBBS, published data, and thermodynamic data (e.g. for phase egg (AlSiO3OH), K-hollandite (KAlSi3O8)) newly derived on the basis of former high-pressure (HP) experiments. Non-ideal mixing was considered for the solid solution series of garnet (components: pyrope, majorite, almandine) and potassic white mica (components: muscovite, MgAl-celadonite, FeAl-celadonite). For phases such as HP-clinoenstatite ((Mg,Fe)SiO3), Si-spinel ((Fe,Mg)2SiO4), and beta phase ((Mg,Fe)2SiO4) only binary solid solutions, assuming ideal mixing, were taken into account. On the basis of the above data, we constructed petrogenetic grids mainly for the P-T range 6 to 16 GPa and 600 to 1600 ° C. Typical features of these grids are, for instance, the disappearance of K-cymrite (KAlSi3O8 H2O) with rising pressure close to 10 GPa and the occurrence of phase egg above 12 GPa. In KMASH potassic white mica reacts with OH-topaz at about 11 GPa (1000-1200 ° C) to form pyrope + K-hollandite. The content of majorite component in pyrope is less than 1 mol% which is systematically so for all garnets coexisting with an Al-silicate at least up to 16 GPa. Potassic white mica, which is virtually pure MgAl-celadonite, finally breaks down at pressures close to 12 GPa. Decomposition assemblages are K-hollandite + HP-clinoenstatite + H2O (T free) garnet + Al-silicate. The latter phase is either OH-topaz (Al2SiO4(OH)2) or phase egg or kyanite also depending on the availability of H2O. Metagranitoids should be composed of shishovite + K-hollandite + majorite-bearing garnet + (enstatite-rich) clinopyroxene. Si-spinel is an important additional phase in this assemblage. This phase shows increasing amounts by approaching to 16 GPa.

  2. Spectroscopic Studies of the Vibrational and Electronic Properties of Solid Hydrogen to 285 GPa

    OpenAIRE

    Goncharov, Alexander F.; Gregoryanz, Eugene; Hemley, Russell J.; Mao, Ho-kwang

    2001-01-01

    We report Raman scattering and visible to near-infrared absorption spectra of solid hydrogen under static pressure up to 285 GPa between 20 and 140 K. We obtain pressure dependences of vibron and phonon modes consistent with results previously determined to lower pressures. The results indicate the stability of the ordered molecular phase III to the highest pressure reached and provide constraints on the insulator-to-metal transition pressure.

  3. miRNA independent hepacivirus variants suggest a strong evolutionary pressure to maintain miR-122 dependence

    DEFF Research Database (Denmark)

    Yu, Yingpu; Scheel, Troels K.H.; Luna, Joseph M.

    2017-01-01

    Hepatitis C virus (HCV) requires the liver specific micro-RNA (miRNA), miR-122, to replicate. This was considered unique among RNA viruses until recent discoveries of HCV-related hepaciviruses prompting the question of a more general miR-122 dependence. Among hepaciviruses, the closest known HCV...... generated infectious NPHV/HCV chimeric viruses with the 5’ end of NPHV replacing orthologous HCV sequences. These chimeras were viable even in cells lacking miR-122, although miR-122 presence enhanced virus production. No other miRNAs bound this region. By random mutagenesis, we isolated HCV variants...... partially dependent on miR-122 as well as robustly replicating NPHV/HCV variants completely independent of any miRNAs. These miRNA independent variants even replicate and produce infectious particles in non-hepatic cells after exogenous delivery of apolipoprotein E (ApoE). Our findings suggest that miR-122...

  4. Unitary Dynamics of Strongly Interacting Bose Gases with the Time-Dependent Variational Monte Carlo Method in Continuous Space

    Science.gov (United States)

    Carleo, Giuseppe; Cevolani, Lorenzo; Sanchez-Palencia, Laurent; Holzmann, Markus

    2017-07-01

    We introduce the time-dependent variational Monte Carlo method for continuous-space Bose gases. Our approach is based on the systematic expansion of the many-body wave function in terms of multibody correlations and is essentially exact up to adaptive truncation. The method is benchmarked by comparison to an exact Bethe ansatz or existing numerical results for the integrable Lieb-Liniger model. We first show that the many-body wave function achieves high precision for ground-state properties, including energy and first-order as well as second-order correlation functions. Then, we study the out-of-equilibrium, unitary dynamics induced by a quantum quench in the interaction strength. Our time-dependent variational Monte Carlo results are benchmarked by comparison to exact Bethe ansatz results available for a small number of particles, and are also compared to quench action results available for noninteracting initial states. Moreover, our approach allows us to study large particle numbers and general quench protocols, previously inaccessible beyond the mean-field level. Our results suggest that it is possible to find correlated initial states for which the long-term dynamics of local density fluctuations is close to the predictions of a simple Boltzmann ensemble.

  5. The extent to which ATP demand controls the glycolytic flux depends strongly on the organism and conditions for growth

    DEFF Research Database (Denmark)

    Købmann, Brian Jensen; Westerhoff, H.V.; Snoep, J.L.

    2002-01-01

    Using molecular genetics we have introduced uncoupled ATPase activity in two different bacterial species, Escherichia coli and Lactococcus lactis, and determined the elasticities of the growth rate and glycolytic flux towards the intracellular [ATP]/[ADP] ratio. During balanced growth in batch...... cultures of E. coli the ATP demand was found to have almost full control on the glycolytic flux (FCC=0.96) and the flux could be stimulated by 70%. In contrast to this, in L. lactis the control by ATP demand on the glycolytic flux was close to zero. However, when we used non-growing cells of L. lactis...... (which have a low glycolytic flux) the ATP demand had a high flux control and the flux could be stimulated more than two fold. We suggest that the extent to which ATP demand controls the glycolytic flux depends on how much excess capacity of glycolysis is present in the cells....

  6. SU-C-304-07: Are Small Field Detector Correction Factors Strongly Dependent On Machine-Specific Characteristics?

    International Nuclear Information System (INIS)

    Mathew, D; Tanny, S; Parsai, E; Sperling, N

    2015-01-01

    Purpose: The current small field dosimetry formalism utilizes quality correction factors to compensate for the difference in detector response relative to dose deposited in water. The correction factors are defined on a machine-specific basis for each beam quality and detector combination. Some research has suggested that the correction factors may only be weakly dependent on machine-to-machine variations, allowing for determinations of class-specific correction factors for various accelerator models. This research examines the differences in small field correction factors for three detectors across two Varian Truebeam accelerators to determine the correction factor dependence on machine-specific characteristics. Methods: Output factors were measured on two Varian Truebeam accelerators for equivalently tuned 6 MV and 6 FFF beams. Measurements were obtained using a commercial plastic scintillation detector (PSD), two ion chambers, and a diode detector. Measurements were made at a depth of 10 cm with an SSD of 100 cm for jaw-defined field sizes ranging from 3×3 cm 2 to 0.6×0.6 cm 2 , normalized to values at 5×5cm 2 . Correction factors for each field on each machine were calculated as the ratio of the detector response to the PSD response. Percent change of correction factors for the chambers are presented relative to the primary machine. Results: The Exradin A26 demonstrates a difference of 9% for 6×6mm 2 fields in both the 6FFF and 6MV beams. The A16 chamber demonstrates a 5%, and 3% difference in 6FFF and 6MV fields at the same field size respectively. The Edge diode exhibits less than 1.5% difference across both evaluated energies. Field sizes larger than 1.4×1.4cm2 demonstrated less than 1% difference for all detectors. Conclusion: Preliminary results suggest that class-specific correction may not be appropriate for micro-ionization chamber. For diode systems, the correction factor was substantially similar and may be useful for class-specific reference

  7. Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation.

    Science.gov (United States)

    Zhan, Yihong; Cao, Zhenning; Bao, Ning; Li, Jianbo; Wang, Jun; Geng, Tao; Lin, Hao; Lu, Chang

    2012-06-28

    Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency. In this report, we utilized a flow-through electroporation technique that employed continuous 10Hz-10kHz ac field (based on either sine waves or square waves) for electroporation of cells with defined duration and intensity. Our results reveal that electropermeabilization becomes weaker with increased frequency in this range. In contrast, transfection efficiency with DNA reaches its maximum at medium frequencies (100-1000Hz) in the range. We postulate that the relationship between the transfection efficiency and the ac frequency is determined by combined effects from electrophoretic movement of DNA in the ac field, dependence of the DNA/membrane interaction on the ac frequency, and variation of transfection under different electropermeabilization intensities. The fact that ac electroporation in this frequency range yields high efficiency for transfection (up to ~71% for Chinese hamster ovary cells) and permeabilization suggests its potential for gene delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Quark matter and quark stars in strong magnetic fields at finite temperature within the confined-isospin-density-dependent mass model

    Science.gov (United States)

    Chu, Peng-Cheng; Li, Xiao-Hua; Ma, Hong-Yang; Wang, Bin; Dong, Yu-Min; Zhang, Xiao-Min

    2018-03-01

    We study the properties of strange quark matter (SQM) and quark stars (QSs) in strong magnetic fields within the extended confined isospin-density-dependent mass (CIDDM) model including the temperature dependence of the equivalent mass for quarks. The quark symmetry energy, quark symmetry free energy, and the equation of state (EOS) of SQM in constant magnetic fields at finite temperature are investigated, and it is found that including the temperature dependence in CIDDM model and considering strong magnetic fields can both significantly influence the properties of the SQM and the maximum mass of quark stars. Using the density-dependent magnetic field and assuming two extreme cases for the magnetic field orientation in QSs (the radial orientation in which the local magnetic fields are along the radial direction and the transverse orientation in which the local magnetic fields are randomly oriented but perpendicular to the radial orientation), we analyze the mass-radius relations for different stages of the protoquark stars (PQSs) along the star evolution. Our results indicate that the maximum mass of magnetized PQSs may depend on not only the strength distribution and the orientation of the magnetic fields inside the PQSs, but also the heating process and the cooling process in the star evolution.

  9. The formation of quiescent glomerular endothelial cell monolayer in vitro is strongly dependent on the choice of extracellular matrix coating

    Energy Technology Data Exchange (ETDEWEB)

    Pajęcka, Kamilla, E-mail: kpaj@novonordisk.com [Global Research, Novo Nordisk A/S, Måløv (Denmark); Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus (Denmark); Nielsen, Malik Nygaard [Global Research, Novo Nordisk A/S, Måløv (Denmark); Hansen, Troels Krarup [Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus (Denmark); Williams, Julie M. [Global Research, Novo Nordisk A/S, Måløv (Denmark)

    2017-04-01

    Background and aims: Nephropathy involves pathophysiological changes to the glomerulus. The primary glomerular endothelial cells (GEnCs) have emerged as an important tool for studying glomerulosclerotic mechanisms and in the screening process for drug-candidates. The success of the studies is dependent on the quality of the cell model. Therefore, we set out to establish an easy, reproducible model of the quiescent endothelial monolayer with the use of commercially available extracellular matrices (ECMs). Methods: Primary hGEnCs were seeded on various ECMs. Cell adhesion was monitored by an impedance sensing system. The localization of junctional proteins was assessed by immunofluorescence and the barrier function by passage of fluorescent dextrans and magnitude of VEGF response. Results: All ECM matrices except recombinant human laminin 111 (rhLN111) supported comparable cell proliferation. Culturing hGEnCs on rhLN521, rhLN511 or fibronectin resulted in a physiologically relevant barrier to 70 kDa dextrans which was 82% tighter than that formed on collagen type IV. Furthermore, only hGEnCs cultured on rhLN521 or rhLN511 showed plasma-membrane localized zonula occludens-1 and vascular endothelial cadherin indicative of proper tight and adherens junctions (AJ). Conclusion: We recommend culturing hGEnCs on the mature glomerular basement membrane laminin - rhLN521 – which, as the only commercially available ECM, promotes all of the characteristics of the quiescent hGEnC monolayer: cobblestone morphology, well-defined AJs and physiological perm-selectivity. - Highlights: • rhLN521, rhLN511 and hFN assure physiologically relevant permeability. • rhLN521 and rhLN511 ensure best cell morphology and adherens junction formation. • Collagen IV and I based coating results in disorganized hGEnC monolayer. • Physiologically relevant ECM may lead to down-regulation of self-produced matrices.

  10. The formation of quiescent glomerular endothelial cell monolayer in vitro is strongly dependent on the choice of extracellular matrix coating

    International Nuclear Information System (INIS)

    Pajęcka, Kamilla; Nielsen, Malik Nygaard; Hansen, Troels Krarup; Williams, Julie M.

    2017-01-01

    Background and aims: Nephropathy involves pathophysiological changes to the glomerulus. The primary glomerular endothelial cells (GEnCs) have emerged as an important tool for studying glomerulosclerotic mechanisms and in the screening process for drug-candidates. The success of the studies is dependent on the quality of the cell model. Therefore, we set out to establish an easy, reproducible model of the quiescent endothelial monolayer with the use of commercially available extracellular matrices (ECMs). Methods: Primary hGEnCs were seeded on various ECMs. Cell adhesion was monitored by an impedance sensing system. The localization of junctional proteins was assessed by immunofluorescence and the barrier function by passage of fluorescent dextrans and magnitude of VEGF response. Results: All ECM matrices except recombinant human laminin 111 (rhLN111) supported comparable cell proliferation. Culturing hGEnCs on rhLN521, rhLN511 or fibronectin resulted in a physiologically relevant barrier to 70 kDa dextrans which was 82% tighter than that formed on collagen type IV. Furthermore, only hGEnCs cultured on rhLN521 or rhLN511 showed plasma-membrane localized zonula occludens-1 and vascular endothelial cadherin indicative of proper tight and adherens junctions (AJ). Conclusion: We recommend culturing hGEnCs on the mature glomerular basement membrane laminin - rhLN521 – which, as the only commercially available ECM, promotes all of the characteristics of the quiescent hGEnC monolayer: cobblestone morphology, well-defined AJs and physiological perm-selectivity. - Highlights: • rhLN521, rhLN511 and hFN assure physiologically relevant permeability. • rhLN521 and rhLN511 ensure best cell morphology and adherens junction formation. • Collagen IV and I based coating results in disorganized hGEnC monolayer. • Physiologically relevant ECM may lead to down-regulation of self-produced matrices.

  11. Elastic properties of gallium antimonide monocrystals under pressure up to 6.4 GPa

    International Nuclear Information System (INIS)

    Goncharov, V.A.; Chernysheva, E.V.; Voronov, F.F.

    1986-01-01

    Pulse-phase method was used to investigate path times of longitudinal and transverse ultrasonic waves at room temperature using monocrystalline samples [100], [110] and [111] of semiconducting gallium antimonide up to 8.2 GPa. A pressure value of phase transformation to metal state was determined from abrupt deviation from monotonous change of dependences measured (6.4±0.4)GPa. Sound propagation rates V i , density ρ, effective elastic constants C i j, Debye temperature Θ and Grueneisen microscopic parameters γ i were calculated for GaSb semiconducting phase. It is shown that elastic properties of GaSb low pressure phase correlate to change peculiarities under pressure of carrier energy spectrum. Experimental results and model representations were compared

  12. Phase diagram of antimony up to 31 GPa and 835 K

    Science.gov (United States)

    Coleman, A. L.; Stevenson, M.; McMahon, M. I.; Macleod, S. G.

    2018-04-01

    X-ray powder diffraction experiments using resistively heated diamond anvil cells have been conducted in order to establish the phase behavior of antimony up to 31 GPa and 835 K. The dip in the melting curve at 5.7 GPa and 840 K is identified as the triple point between the Sb-I, incommensurate Sb-II, and liquid phases. No evidence of the previously reported simple cubic phase was observed. Determination of the phase boundary between Sb-II and Sb-III suggests the existence of a second triple point in the region of 13 GPa and 1200 K. The incommensurate composite structure of Sb-II was found to remain ordered to the highest temperatures studies—no evidence of disordering of the guest-atom chains was observed. Indeed, the modulation reflections that arise from interactions between the host and guest subsystems were found to be present to the highest temperatures, suggesting such interactions remain relatively strong in Sb even in the presence of increased thermal motion. Finally, we show that the incommensurately modulated structure recently reported as giving an improved fit to diffraction data from incommensurate Ba-IV can be rejected as the structure of Sb-II using a simple density argument.

  13. Equation of state measurements in liquid deuterium to 100 GPa

    CERN Document Server

    Knudson, M D; Bailey, J E; Lemke, R W; Hall, C A; Deeney, C; Asay, J R

    2003-01-01

    Using intense magnetic pressure, a method was developed to launch flyer plates to velocities in excess of 20 km s sup - sup 1. This technique was used to perform plate-impact, shock wave experiments on cryogenic liquid deuterium (LD sub 2) to examine its high-pressure equation of state (EOS). Using an impedance matching method, Hugoniot measurements were obtained in the pressure range of 22-100 GPa. The results of these experiments disagree with the previously reported Hugoniot measurements of LD sub 2 in the pressure range above approx 40 GPa, but are in good agreement with first principles, ab initio models for hydrogen and its isotopes.

  14. Quantum fluid dynamics based current-density functional study of a helium atom in a strong time-dependent magnetic field

    Science.gov (United States)

    Vikas, Hash(0x125f4490)

    2011-02-01

    Evolution of the helium atom in a strong time-dependent (TD) magnetic field ( B) of strength up to 1011 G is investigated through a quantum fluid dynamics (QFD) based current-density functional theory (CDFT). The TD-QFD-CDFT computations are performed through numerical solution of a single generalized nonlinear Schrödinger equation employing vector exchange-correlation potentials and scalar exchange-correlation density functionals that depend both on the electronic charge-density and the current-density. The results are compared with that obtained from a B-TD-QFD-DFT approach (based on conventional TD-DFT) under similar numerical constraints but employing only scalar exchange-correlation potential dependent on electronic charge-density only. The B-TD-QFD-DFT approach, at a particular TD magnetic field-strength, yields electronic charge- and current-densities as well as exchange-correlation potential resembling with that obtained from the time-independent studies involving static (time-independent) magnetic fields. However, TD-QFD-CDFT electronic charge- and current-densities along with the exchange-correlation potential and energy differ significantly from that obtained using B-TD-QFD-DFT approach, particularly at field-strengths >109 G, representing dynamical effects of a TD field. The work concludes that when a helium atom is subjected to a strong TD magnetic field of order >109 G, the conventional TD-DFT based approach differs "dynamically" from the CDFT based approach under similar computational constraints.

  15. Quantum fluid dynamics based current-density functional study of a helium atom in a strong time-dependent magnetic field

    International Nuclear Information System (INIS)

    Vikas

    2011-01-01

    Evolution of the helium atom in a strong time-dependent (TD) magnetic field (B) of strength up to 10 11 G is investigated through a quantum fluid dynamics (QFD) based current-density functional theory (CDFT). The TD-QFD-CDFT computations are performed through numerical solution of a single generalized nonlinear Schroedinger equation employing vector exchange-correlation potentials and scalar exchange-correlation density functionals that depend both on the electronic charge-density and the current-density. The results are compared with that obtained from a B-TD-QFD-DFT approach (based on conventional TD-DFT) under similar numerical constraints but employing only scalar exchange-correlation potential dependent on electronic charge-density only. The B-TD-QFD-DFT approach, at a particular TD magnetic field-strength, yields electronic charge- and current-densities as well as exchange-correlation potential resembling with that obtained from the time-independent studies involving static (time-independent) magnetic fields. However, TD-QFD-CDFT electronic charge- and current-densities along with the exchange-correlation potential and energy differ significantly from that obtained using B-TD-QFD-DFT approach, particularly at field-strengths >10 9 G, representing dynamical effects of a TD field. The work concludes that when a helium atom is subjected to a strong TD magnetic field of order >10 9 G, the conventional TD-DFT based approach differs 'dynamically' from the CDFT based approach under similar computational constraints. (author)

  16. Efficient three-photon luminescence with strong polarization dependence from a scintillating silicate glass co-doped with Gd3+ and Tb3+.

    Science.gov (United States)

    Li, Guang-Can; Zhang, Cheng-Yun; Deng, Hai-Dong; Liu, Guang-Yin; Lan, Sheng; Qian, Qi-; Yang, Zhong-Min; Gopal, Achanta Venu

    2013-03-11

    Efficient three-photon luminescence (3PL) from a scintillating silicate glass co-doped with Gd(3+) and Tb(3+) was generated by using a focused femtosecond laser beam at 800 nm. Four emission bands centered at 496, 541, 583, and 620 nm were identified as the electronic transitions between the energy levels of Tb(3+) followed by three-photon absorption (3PA) in Gd(3+) and Tb(3+) and the resonant energy transfer from Gd(3+) to Tb(3+). More interestingly, a strong polarization dependence of the 3PL was observed and it is ascribed to the polarization dependent 3PA in Gd(3+) and Tb(3+) and/or the angular distribution of photogenerated electrons in the glass.

  17. Strike Four! Do-Over Policies Institutionalize GPA Distortion

    Science.gov (United States)

    Marx, Jonathan; Meeler, David

    2013-01-01

    Purpose: The aim of this paper is to illustrate how universities play an institutional role in inflating student grade point averages (GPA) by modifying academic polices such as course withdraw, repeats, and satisfactory/unsatisfactory grade options. Design/methodology/approach: Three research strategies are employed: an examination of eight…

  18. Measuring Association between Library Instruction and Graduation GPA

    Science.gov (United States)

    Wong, Shun Han Rebekah; Cmor, Dianne

    2011-01-01

    Academic libraries devote considerable human resources in delivering library instruction programs. This study attempts to determine if these instructional efforts have any measurable effect on student performance in terms of overall grades. Library workshop attendance and graduation GPA of over 8,000 students was analyzed at Hong Kong Baptist…

  19. What Does GPA in an Urban High School Actually Mean?

    Science.gov (United States)

    Steward, Robbie J.; Hill, Martin F.; Neil, Douglas M.; Pritchett, Tiffany; Wabaunsee, Ah-Sha-Ni

    2008-01-01

    The purpose of this researcher-school collaborative study was to examine factors which might be intervenable by urban high school counselors in assisting at-risk students. There were two primary objectives. The first was to examine the degree to which urban adolescents' academic competence predicts cumulative grade point average (GPA). The second…

  20. Electronic transport properties of MFe2As2 (M = Ca, Eu, Sr) at ambient and high pressures up to 20 GPa

    Science.gov (United States)

    Morozova, Natalia V.; Karkin, Alexander E.; Ovsyannikov, Sergey V.; Umerova, Yuliya A.; Shchennikov, Vladimir V.; Mittal, R.; Thamizhavel, A.

    2015-12-01

    We experimentally investigated the electronic transport properties of four iron pnictide crystals, namely, EuFe2As2, SrFe2As2, and CaFe2As2 parent compounds, and superconducting CaFe1.94Co0.06As2 at ambient and high pressures up to 20 GPa. At ambient pressure we examined the electrical resistivity, Hall and magnetoresistance effects of the samples in a temperature range from 1.5 to 380 K in high magnetic fields up to 13.6 T. In this work we carried out the first simultaneous investigations of the in-plane and out-of-plane Hall coefficients, and found new peculiarities of the low-temperature magnetic and structural transitions that occur in these materials. In addition, the Hall coefficient data suggested that the parent compounds are semimetals with a multi-band conductivity that includes hole-type and electron-type bands. We measured the pressure dependence of the thermoelectric power (the Seebeck effect) of these samples up to 20 GPa, i.e. across the known phase transition from the tetragonal to the collapsed tetragonal lattice. The high-pressure behavior of the thermopower of EuFe2As2 and CaFe2As2 showing the p-n sign inversions was consistent with the semimetal model described above. By means of thermopower, we found in single-crystalline CaFe2As2 direct evidence of the band structure crossover related to the formation of As-As bonds along the c-axis on the tetragonal → collapsed tetragonal phase transition near 2 GPa. We showed that this feature is distinctly observable only in high-quality samples, and already for re-pressurization cycles this crossover was strongly smeared because of the moderate deterioration of the sample. We also demonstrated by means of thermopower that the band structure crossover that should accompany the tetragonal → collapsed tetragonal phase transition in EuFe2As2 near 8 GPa is hardly visible even in high-quality single crystals. This behavior may be related to a gradual valence change of the Eu ions under pressure that leads to

  1. Electronic transport properties of MFe2As2 (M = Ca, Eu, Sr) at ambient and high pressures up to 20 GPa

    International Nuclear Information System (INIS)

    Morozova, Natalia V; Karkin, Alexander E; Umerova, Yuliya A; Shchennikov, Vladimir V; Ovsyannikov, Sergey V; Mittal, R; Thamizhavel, A

    2015-01-01

    We experimentally investigated the electronic transport properties of four iron pnictide crystals, namely, EuFe 2 As 2 , SrFe 2 As 2 , and CaFe 2 As 2 parent compounds, and superconducting CaFe 1.94 Co 0.06 As 2 at ambient and high pressures up to 20 GPa. At ambient pressure we examined the electrical resistivity, Hall and magnetoresistance effects of the samples in a temperature range from 1.5 to 380 K in high magnetic fields up to 13.6 T. In this work we carried out the first simultaneous investigations of the in-plane and out-of-plane Hall coefficients, and found new peculiarities of the low-temperature magnetic and structural transitions that occur in these materials. In addition, the Hall coefficient data suggested that the parent compounds are semimetals with a multi-band conductivity that includes hole-type and electron-type bands. We measured the pressure dependence of the thermoelectric power (the Seebeck effect) of these samples up to 20 GPa, i.e. across the known phase transition from the tetragonal to the collapsed tetragonal lattice. The high-pressure behavior of the thermopower of EuFe 2 As 2 and CaFe 2 As 2 showing the p-n sign inversions was consistent with the semimetal model described above. By means of thermopower, we found in single-crystalline CaFe 2 As 2 direct evidence of the band structure crossover related to the formation of As–As bonds along the c-axis on the tetragonal → collapsed tetragonal phase transition near 2 GPa. We showed that this feature is distinctly observable only in high-quality samples, and already for re-pressurization cycles this crossover was strongly smeared because of the moderate deterioration of the sample. We also demonstrated by means of thermopower that the band structure crossover that should accompany the tetragonal → collapsed tetragonal phase transition in EuFe 2 As 2 near 8 GPa is hardly visible even in high-quality single crystals. This behavior may be related to a gradual valence change of the Eu

  2. Quantum fluid dynamics based current-density functional study of a helium atom in a strong time-dependent magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Vikas [Quantum Chemistry Group, Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, 160014 Chandigrah (India)

    2011-02-15

    Evolution of the helium atom in a strong time-dependent (TD) magnetic field (B) of strength up to 10{sup 11} G is investigated through a quantum fluid dynamics (QFD) based current-density functional theory (CDFT). The TD-QFD-CDFT computations are performed through numerical solution of a single generalized nonlinear Schroedinger equation employing vector exchange-correlation potentials and scalar exchange-correlation density functionals that depend both on the electronic charge-density and the current-density. The results are compared with that obtained from a B-TD-QFD-DFT approach (based on conventional TD-DFT) under similar numerical constraints but employing only scalar exchange-correlation potential dependent on electronic charge-density only. The B-TD-QFD-DFT approach, at a particular TD magnetic field-strength, yields electronic charge- and current-densities as well as exchange-correlation potential resembling with that obtained from the time-independent studies involving static (time-independent) magnetic fields. However, TD-QFD-CDFT electronic charge- and current-densities along with the exchange-correlation potential and energy differ significantly from that obtained using B-TD-QFD-DFT approach, particularly at field-strengths >10{sup 9} G, representing dynamical effects of a TD field. The work concludes that when a helium atom is subjected to a strong TD magnetic field of order >10{sup 9} G, the conventional TD-DFT based approach differs 'dynamically' from the CDFT based approach under similar computational constraints. (author)

  3. Thickness Dependence of Magnetic Relaxation and E-J Characteristics in Superconducting (Gd-Y)-Ba-Cu-O Films with Strong Vortex Pinning

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Sinclair IV, John W [ORNL; Zuev, Yuri L [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Cook, Sylvester W [ORNL; Kumar, Dhananjay [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    The dependence of the critical current density Jc on temperature, magnetic field, and film thickness has been investigated in (Gd-Y)BaCu-oxide materials of 0.7, 1.4, and 2.8 m thickness. Generally, the Jc decreases with film thickness at investigated temperatures and magnetic fields. The nature and strength of the pinning centers for vortices have been identified through angular and temperature measurements, respectively. These films do not exhibit c-axis correlated vortex pinning, but do have correlated defects oriented near the ab-planes. For all film thicknesses studied, strong pinning dominates at most temperatures. The vortex dynamics were investigated through magnetic relaxation studies in the temperature range of 5 77 K in 1 T and 3 T applied magnetic fields, H || surface-normal. The creep rate S is thickness dependent at high temperatures, implying that the pinning energy is also thickness dependent. Maley analyses of the relaxation data show an inverse power law variation for the effective pinning energy Ueff ~ (J0/J) . Finally, the electric field-current density (E-J) characteristics were determined over a wide range of dissipation by combining experimental results from transport, swept field magnetometry (VSM), and Superconducting Quantum Interference Device (SQUID) magnetometry. We develop a self-consistent model of the combined experimental results, leading to an estimation of the critical current density Jc0(T) in the absence of flux creep.

  4. Strongly Nonlinear Dependence of Energy Transfer Rate on sp(2) Carbon Content in Reduced Graphene Oxide-Quantum Dot Hybrid Structures.

    Science.gov (United States)

    Dong, Yitong; Son, Dong Hee

    2015-01-02

    The dependence of the energy transfer rate on the content of sp(2)-hybridized carbon atoms in the hybrid structures of reduced graphene oxide (RGO) and Mn-doped quantum dot (QD(Mn)) was investigated. Taking advantage of the sensitivity of QD(Mn)'s dopant luminescence lifetime only to the energy transfer process without interference from the charge transfer process, the correlation between the sp(2) carbon content in RGO and the rate of energy transfer from QD(Mn) to RGO was obtained. The rate of energy transfer showed a strongly superlinear increase with increasing sp(2) carbon content in RGO, suggesting the possible cooperative behavior of sp(2) carbon domains in the energy transfer process as the sp(2) carbon content increases.

  5. Verification test problems for the calculation of probability of loss of assured safety in temperature-dependent systems with multiple weak and strong links.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jay Dean (ProStat, Mesa, AZ); Oberkampf, William Louis; Helton, Jon Craig (Arizona State University, Tempe, AZ)

    2006-06-01

    Four verification test problems are presented for checking the conceptual development and computational implementation of calculations to determine the probability of loss of assured safety (PLOAS) in temperature-dependent systems with multiple weak links (WLs) and strong links (SLs). The problems are designed to test results obtained with the following definitions of loss of assured safety: (1) Failure of all SLs before failure of any WL, (2) Failure of any SL before failure of any WL, (3) Failure of all SLs before failure of all WLs, and (4) Failure of any SL before failure of all WLs. The test problems are based on assuming the same failure properties for all links, which results in problems that have the desirable properties of fully exercising the numerical integration procedures required in the evaluation of PLOAS and also possessing simple algebraic representations for PLOAS that can be used for verification of the analysis.

  6. The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 GPa and 300–800 °C

    Energy Technology Data Exchange (ETDEWEB)

    Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver; Chow, Paul; Xiao, Yuming; Burnley, Pamela; Cline II, Christopher J.; Hanchar, John M.; Pettke, Thomas; Shen, Guoyin; Zhao, Yusheng (MUN); (Michigan); (CIW); (UNLV); (Bern)

    2015-08-26

    Rutile (TiO₂) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 °C). In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300–500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at ~1 GPa and 700–800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 μg/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 μg/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. The Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 μg/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥2 GPa, but there is no observed

  7. 40 CFR 80.220 - What are the downstream standards for GPA gasoline?

    Science.gov (United States)

    2010-07-01

    ... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...

  8. The Why, What, and Impact of GPA at Oxford Brookes University

    Science.gov (United States)

    Andrews, Matthew

    2016-01-01

    This paper examines the introduction at Oxford Brookes University of a Grade Point Average (GPA) scheme alongside the traditional honours degree classification. It considers the reasons for the introduction of GPA, the way in which the scheme was implemented, and offers an insight into the impact of GPA at Brookes. Finally, the paper considers…

  9. Carbon dots with strong excitation-dependent fluorescence changes towards pH. Application as nanosensors for a broad range of pH

    Energy Technology Data Exchange (ETDEWEB)

    Barati, Ali [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of); Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Abdollahi, Hamid, E-mail: abd@iasbs.ac.ir [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of)

    2016-08-10

    In this study, preparation of novel pH-sensitive N-doped carbon dots (NCDs) using glucose and urea is reported. The prepared NCDs present strong excitation-dependent fluorescence changes towards the pH that is a new behavior from these nanomaterials. By taking advantage of this unique behavior, two separated ratiometric pH sensors using emission spectra of the NCDs for both acidic (pH 2.0 to 8.0) and basic (pH 7.0 to 14.0) ranges of pH are constructed. Additionally, by considering the entire Excitation–Emission Matrix (EEM) of NCDs as analytical signal and using a suitable multivariate calibration method, a broad range of pH from 2.0 to 14.0 was well calibrated. The multivariate calibration method was independent from the concentration of NCDs and resulted in a very low average prediction error of 0.067 pH units. No changes in the predicted pH under UV irradiation (for 3 h) and at high ionic strength (up to 2 M NaCl) indicated the high stability of this pH nanosensor. The practicality of this pH nanosensor for pH determination in real water samples was validated with good accuracy and repeatability. - Highlights: • Novel pH-sensitive carbon dots with strong FL changes towards pH are reported. • Ratiometric FL pH-sensors for both acidic and basic ranges of pH are constructed. • Multivariate calibration methods were used to calibrate a broad range of pH. • Using EEM of carbon dots and ANN, pH from 2.0 to 14.0 was well calibrated. • The pH prediction is stable even at high ionic strength up to 2 M NaCl.

  10. Vibrational tug-of-war: The pKA dependence of the broad vibrational features of strongly hydrogen-bonded carboxylic acids

    Science.gov (United States)

    Van Hoozen, Brian L.; Petersen, Poul B.

    2018-04-01

    of strongly hydrogen-bonded structures depend on the relative pKA and other structural parameters will guide studies of biological structures and analysis of proton transfer studies using photoacids.

  11. Excision Efficiency Is Not Strongly Coupled to Transgenic Rate: Cell Type-Dependent Transposition Efficiency of Sleeping Beauty and piggyBac DNA Transposons

    Science.gov (United States)

    Kolacsek, Orsolya; Erdei, Zsuzsa; Apáti, Ágota; Sándor, Sára; Izsvák, Zsuzsanna; Ivics, Zoltán; Sarkadi, Balázs

    2014-01-01

    Abstract The Sleeping Beauty (SB) and piggyBac (PB) DNA transposons represent an emerging new gene delivery technology, potentially suitable for human gene therapy applications. Previous studies pointed to important differences between these transposon systems, depending on the cell types examined and the methodologies applied. However, efficiencies cannot always be compared because of differences in applications. In addition, “overproduction inhibition,” a phenomenon believed to be a characteristic of DNA transposons, can remarkably reduce the overall transgenic rate, emphasizing the importance of transposase dose applied. Therefore, because of lack of comprehensive analysis, researchers are forced to optimize the technology for their own “in-house” platforms. In this study, we investigated the transposition of several SB (SB11, SB32, SB100X) and PB (mPB and hyPB) variants in various cell types at three levels: comparing the excision efficiency of the reaction by real-time PCR, testing the overall transgenic rate by detecting cells with stable integrations, and determining the average copy number when using different transposon systems and conditions. We concluded that high excision activity is not always followed by a higher transgenic rate, as exemplified by the hyperactive transposases, indicating that the excision and the integration steps of transposition are not strongly coupled as previously thought. In general, all levels of transposition show remarkable differences depending on the transposase used and cell lines examined, being the least efficient in human embryonic stem cells (hESCs). In spite of the comparably low activity in those special cell types, the hyperactive SB100X and hyPB systems could be used in hESCs with similar transgenic efficiency and with reasonably low (2–3) transgene copy numbers, indicating their potential applicability for gene therapy purposes in the future. PMID:25045962

  12. Carbon dots with strong excitation-dependent fluorescence changes towards pH. Application as nanosensors for a broad range of pH.

    Science.gov (United States)

    Barati, Ali; Shamsipur, Mojtaba; Abdollahi, Hamid

    2016-08-10

    In this study, preparation of novel pH-sensitive N-doped carbon dots (NCDs) using glucose and urea is reported. The prepared NCDs present strong excitation-dependent fluorescence changes towards the pH that is a new behavior from these nanomaterials. By taking advantage of this unique behavior, two separated ratiometric pH sensors using emission spectra of the NCDs for both acidic (pH 2.0 to 8.0) and basic (pH 7.0 to 14.0) ranges of pH are constructed. Additionally, by considering the entire Excitation-Emission Matrix (EEM) of NCDs as analytical signal and using a suitable multivariate calibration method, a broad range of pH from 2.0 to 14.0 was well calibrated. The multivariate calibration method was independent from the concentration of NCDs and resulted in a very low average prediction error of 0.067 pH units. No changes in the predicted pH under UV irradiation (for 3 h) and at high ionic strength (up to 2 M NaCl) indicated the high stability of this pH nanosensor. The practicality of this pH nanosensor for pH determination in real water samples was validated with good accuracy and repeatability. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Hormonal regulation of gluconeogenesis in cereal aleurone is strongly cultivar-dependent and gibberellin action involves SLENDER1 but not GAMYB.

    Science.gov (United States)

    Eastmond, Peter J; Jones, Russell L

    2005-11-01

    Storage oil is a major constituent in the cereal aleurone layer. The aim of this study was to investigate how gibberellin (GA) and abscisic acid (ABA) regulate conversion of oil to sugar in barley aleurone. The activity of the glyoxylate cycle enzyme isocitrate lyase (ICL) was surveyed in eight barley cultivars. Surprisingly, some cultivars do not require GA for the induction of ICL (e.g. Himalaya), whereas some do (e.g. Golden Promise). Furthermore, in Golden Promise, GA also stimulates triacylglycerol breakdown and enhances the net flux of carbon from acetate to sugar. In contrast, ABA strongly represses ICL activity and the flux of carbon from oil to sugar in both Golden Promise and Himalaya. Biolistics using a promoter reporter showed that GA and ABA regulate ICL at the level of transcription. Studies using barley and rice mutants and pharmacological agents show that GA-dependent induction of ICL activity is mediated by SLENDER1 and requires cGMP, but does not involve the transcription factor GAMYB. Gibberellin and ABA therefore act antagonistically to regulate gluconeogenesis in the aleurone layer as well as controlling the production and secretion of hydrolases into the starchy endosperm. We suggest that the variation between different barley cultivars might be a result of selective breeding to alter seed dormancy.

  14. Effect of delayed link failure on probability of loss of assured safety in temperature-dependent systems with multiple weak and strong links.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J. D. (ProStat, Mesa, AZ); Oberkampf, William Louis; Helton, Jon Craig (Arizona State University, Tempe, AZ)

    2007-05-01

    Weak link (WL)/strong link (SL) systems constitute important parts of the overall operational design of high consequence systems, with the SL system designed to permit operation of the system only under intended conditions and the WL system designed to prevent the unintended operation of the system under accident conditions. Degradation of the system under accident conditions into a state in which the WLs have not deactivated the system and the SLs have failed in the sense that they are in a configuration that could permit operation of the system is referred to as loss of assured safety. The probability of such degradation conditional on a specific set of accident conditions is referred to as probability of loss of assured safety (PLOAS). Previous work has developed computational procedures for the calculation of PLOAS under fire conditions for a system involving multiple WLs and SLs and with the assumption that a link fails instantly when it reaches its failure temperature. Extensions of these procedures are obtained for systems in which there is a temperature-dependent delay between the time at which a link reaches its failure temperature and the time at which that link actually fails.

  15. Correlation Between Ability on Playing Tetris and GPA

    Directory of Open Access Journals (Sweden)

    Aprilia Ratna Christanti

    2014-10-01

    Full Text Available The goal of this study is to determine the correlation between ability on playing Tetris and GPA of Soegijapranata Catholic University, Department of Information System students against the dexterity in playing Tetris. The research has been done using experiment method on ten Information System students who have various grade points. They played Tetris, 30 minutes each, for three consecutive days. The results showed that: First, eight out of the ten students improved their agility. It can be seen from the increasing scores and levels; Second, the coefficient correlation between student grade point and dexterity in playing Tetris is by 62%. Keywords Ability, grade point average, Tetris

  16. Use of the Graded Prognostic Assessment (GPA) score in patients with brain metastases from primary tumours not represented in the diagnosis-specific GPA studies

    Energy Technology Data Exchange (ETDEWEB)

    Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Medicine; Tromsoe Univ. (Norway). Inst. of Clinical Medicine; Andratschke, N.H. [University Hospital Rostock (Germany). Dept. of Radiation Oncology; Geinitz, H. [Klinikum rechts der Isar der Technischen Univ. Muenchen (Germany). Dept. of Radiation Oncology; Grosu, A.L. [University Hospital Freiburg (Germany). Dept. of Radiation Oncology

    2012-08-15

    Background and purpose: Assessment of prognostic factors might influence treatment decisions in patients with brain metastases. Based on large studies, the diagnosis-specific graded prognostic assessment (GPA) score is a useful tool. However, patients with unknown or rare primary tumours are not represented in this model. A pragmatic approach might be use of the first GPA version which is not limited to specific primary tumours. Patients and methods: This retrospective analysis examines for the first time whether the GPA is a valid score in patients not eligible for the diagnosis-specific GPA. It includes 71 patients with unknown primary tumour, bladder cancer, ovarian cancer, thyroid cancer or other uncommon primaries. Survival was evaluated in uni- and multivariate tests. Results: The GPA significantly predicted survival. Moreover, improved survival was seen in patients treated with surgical resection or radiosurgery (SRS) for brain metastases. The older recursive partitioning analysis (RPA) score was significant in univariate analysis. However, the multivariate model with RPA, GPA and surgery or SRS versus none showed that only GPA and type of treatment were independent predictors of survival. Conclusion: Ideally, cooperative research efforts would lead to development of diagnosis-specific scores also for patients with rare or unknown primary tumours. In the meantime, a pragmatic approach of using the general GPA score appears reasonable. (orig.)

  17. Use of the Graded Prognostic Assessment (GPA) score in patients with brain metastases from primary tumours not represented in the diagnosis-specific GPA studies

    International Nuclear Information System (INIS)

    Nieder, C.; Tromsoe Univ.; Andratschke, N.H.; Geinitz, H.; Grosu, A.L.

    2012-01-01

    Background and purpose: Assessment of prognostic factors might influence treatment decisions in patients with brain metastases. Based on large studies, the diagnosis-specific graded prognostic assessment (GPA) score is a useful tool. However, patients with unknown or rare primary tumours are not represented in this model. A pragmatic approach might be use of the first GPA version which is not limited to specific primary tumours. Patients and methods: This retrospective analysis examines for the first time whether the GPA is a valid score in patients not eligible for the diagnosis-specific GPA. It includes 71 patients with unknown primary tumour, bladder cancer, ovarian cancer, thyroid cancer or other uncommon primaries. Survival was evaluated in uni- and multivariate tests. Results: The GPA significantly predicted survival. Moreover, improved survival was seen in patients treated with surgical resection or radiosurgery (SRS) for brain metastases. The older recursive partitioning analysis (RPA) score was significant in univariate analysis. However, the multivariate model with RPA, GPA and surgery or SRS versus none showed that only GPA and type of treatment were independent predictors of survival. Conclusion: Ideally, cooperative research efforts would lead to development of diagnosis-specific scores also for patients with rare or unknown primary tumours. In the meantime, a pragmatic approach of using the general GPA score appears reasonable. (orig.)

  18. Endogenous proteolytic cleavage of disease-associated prion protein to produce C2 fragments is strongly cell- and tissue-dependent.

    Science.gov (United States)

    Dron, Michel; Moudjou, Mohammed; Chapuis, Jérôme; Salamat, Muhammad Khalid Farooq; Bernard, Julie; Cronier, Sabrina; Langevin, Christelle; Laude, Hubert

    2010-04-02

    The abnormally folded form of the prion protein (PrP(Sc)) accumulating in nervous and lymphoid tissues of prion-infected individuals can be naturally cleaved to generate a N-terminal-truncated fragment called C2. Information about the identity of the cellular proteases involved in this process and its possible role in prion biology has remained limited and controversial. We investigated PrP(Sc) N-terminal trimming in different cell lines and primary cultured nerve cells, and in the brain and spleen tissue from transgenic mice infected by ovine and mouse prions. We found the following: (i) the full-length to C2 ratio varies considerably depending on the infected cell or tissue. Thus, in primary neurons and brain tissue, PrP(Sc) accumulated predominantly as untrimmed species, whereas efficient trimming occurred in Rov and MovS cells, and in spleen tissue. (ii) Although C2 is generally considered to be the counterpart of the PrP(Sc) proteinase K-resistant core, the N termini of the fragments cleaved in vivo and in vitro can actually differ, as evidenced by a different reactivity toward the Pc248 anti-octarepeat antibody. (iii) In lysosome-impaired cells, the ratio of full-length versus C2 species dramatically increased, yet efficient prion propagation could occur. Moreover, cathepsin but not calpain inhibitors markedly inhibited C2 formation, and in vitro cleavage by cathepsins B and L produced PrP(Sc) fragments lacking the Pc248 epitope, strongly arguing for the primary involvement of acidic hydrolases of the endolysosomal compartment. These findings have implications on the molecular analysis of PrP(Sc) and cell pathogenesis of prion infection.

  19. Endogenous Proteolytic Cleavage of Disease-associated Prion Protein to Produce C2 Fragments Is Strongly Cell- and Tissue-dependent*

    Science.gov (United States)

    Dron, Michel; Moudjou, Mohammed; Chapuis, Jérôme; Salamat, Muhammad Khalid Farooq; Bernard, Julie; Cronier, Sabrina; Langevin, Christelle; Laude, Hubert

    2010-01-01

    The abnormally folded form of the prion protein (PrPSc) accumulating in nervous and lymphoid tissues of prion-infected individuals can be naturally cleaved to generate a N-terminal-truncated fragment called C2. Information about the identity of the cellular proteases involved in this process and its possible role in prion biology has remained limited and controversial. We investigated PrPSc N-terminal trimming in different cell lines and primary cultured nerve cells, and in the brain and spleen tissue from transgenic mice infected by ovine and mouse prions. We found the following: (i) the full-length to C2 ratio varies considerably depending on the infected cell or tissue. Thus, in primary neurons and brain tissue, PrPSc accumulated predominantly as untrimmed species, whereas efficient trimming occurred in Rov and MovS cells, and in spleen tissue. (ii) Although C2 is generally considered to be the counterpart of the PrPSc proteinase K-resistant core, the N termini of the fragments cleaved in vivo and in vitro can actually differ, as evidenced by a different reactivity toward the Pc248 anti-octarepeat antibody. (iii) In lysosome-impaired cells, the ratio of full-length versus C2 species dramatically increased, yet efficient prion propagation could occur. Moreover, cathepsin but not calpain inhibitors markedly inhibited C2 formation, and in vitro cleavage by cathepsins B and L produced PrPSc fragments lacking the Pc248 epitope, strongly arguing for the primary involvement of acidic hydrolases of the endolysosomal compartment. These findings have implications on the molecular analysis of PrPSc and cell pathogenesis of prion infection. PMID:20154089

  20. Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity.

    Science.gov (United States)

    Kocsmár, Éva; Szirtes, Ildikó; Kramer, Zsófia; Szijártó, Attila; Bene, László; Buzás, György Miklós; Kenessey, István; Bronsert, Peter; Csanadi, Agnes; Lutz, Lisa; Werner, Martin; Wellner, Ulrich Friedrich; Kiss, András; Schaff, Zsuzsa; Lotz, Gábor

    2017-08-01

    Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP). We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations. Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings. We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP. © 2017 John Wiley & Sons Ltd.

  1. Carbonated Eclogite Solidus Between 14 and 20 GPa: Results from the Model CMAS-CO2 System and Contrasting Solidus Behavior to Carbonated Peridotite

    Science.gov (United States)

    Keshav, S.; Gudfinnsson, G. H.

    2007-12-01

    , and magnesite. From average calculated melting reactions along these isobarically univariant curves, stishovite is produced upon melting at all pressures investigated. Significantly, cpx at 14 and 16 GPa and capv at 20 GPa are the dominant contributors toward melt production/composition, in contrast to lower pressures (3-8 GPa) where carbonate dominantly contributes toward melt generation/composition at the solidus. The solidus of model carbonated eclogite at 14, 16, and 20 GPa, lies at 1350, 1450, and 1600 degrees C, respectively, and is nearly linear in P-T space. Melts in equilibrium with all the crystalline phases are highly calcic (Ca no.-0.70), resembling calcio-carbonatites. When magnesite is exhausted from the crystalline assemblage, the melts become slightly less calcic (Ca no.-65). The model carbonated eclogite solidus is always lower than the model carbonated peridotite solidus in the same pressure range. The most remarkable feature of this work is the absence of a drop in the solidus of model carbonated eclogite between 14 and 16 GPa, a result that is in stark contrast to that observed for the model carbonated peridotite at identical pressures. Therefore, even though the solidus temperatures in both carbonated peridotite and eclogite are strongly influenced by the presence of crystalline carbonate, melt compositions and the shape of the solidus in the pressure range investigated seem to be dominantly controlled by the silicate component of the rock in question. Given these results, it is fair to say that a wide range of petrological and geochemical processes operate at these depths in the mantle, and that we have barely scratched the surface in our investigation.

  2. Elastic Constants of Brucite (Mg(OH)2) and Diaspore (AlO(OH)) to 12 GPa by Brillouin Scattering

    Science.gov (United States)

    Jiang, F.; Speziale, S.; Majzlan, J.; Duffy, T. S.

    2005-12-01

    Hydroxides such as brucite, Mg(OH)2, and diaspore, AlO(OH), serve as analogs for the more complex hydrogen-bearing minerals found in subduction zones. The single-crystal elastic constants of these two minerals were determined by Brillouin scattering up to 12 GPa in a diamond anvil cell. A 16:3:1 methanol-ethanol-water and 4:1 methanol-ethanol mixture were used as pressure media and ruby as pressure calibrant. Two platelets of brucite and three platelets of diaspore were measured at room pressure and over nine elevated pressures. Brillouin spectra were recorded in 37 directions with a 5-degree step for each plane. All individual elastic stiffness constants were retrieved by fitting the velocity data to the Christoffel's equation. The individual elastic constants, aggregate bulk and shear moduli, were then fitted to the finite Eulerian stain equations to obtain their pressure derivatives. For brucite, aggregate moduli and their pressure derivatives are KT0=35.9(9) GPa, GO=31.3(2) GPa, (∂ Kt/∂ P)T0=8.9(3), (∂ G/∂ P)O=4.33(4) for the Reuss bound. Diaspore aggregate moduli and their pressure derivatives are KT0=147.0(7) GPa, GO=114.8(5) GPa, (∂ Ks/∂ P)T0=4.1(1), (∂ G/∂ P)O=1.6(1). For diaspore, both individual and aggregate elastic moduli define nearly linear modulus pressure trend within the measured pressure range. For Brucite, there are clear deviations from linear modulus - pressure trends. In comparison with diaspore, brucite exhibits strong anisotropy. The ratio of the linear compressibility of brucite along the c and a axes decreased from 4.7 to 1.3 over the examined pressure range. The shear anisotropy (C66/C44) decreased from 2.6 at ambient condition to 1.3 with increase of pressure to 12 GPa. Compression curves constructed from our Brillouin data for both brucite and diaspore are in good agreement with previous x-ray diffraction data.

  3. Superbainite. A novel very strong bainitic microstructure

    International Nuclear Information System (INIS)

    Garcia-Mateo, C.; Caballero, E. G.; Bhadeshia, H. K. D. H.

    2005-01-01

    In this work very recent results are how that reveals the possibility of obtaining bainite by isothermal transformation at very low temperatures, of about 150 degree centigree, in high carbon high silicon steels. The microstructure thus obtained is a mixture of fine plates of bainite ferrite (20-40 nm thickness) and thin films of carbon enriched austenite. These microstructures are very hard (600 HV) and strong (2.5 GPa). (Author) 18 refs

  4. Unconventional superconductivity in cuprates, cobaltates and graphene. What is universal and what is material-dependent in strongly versus weakly correlated materials?

    International Nuclear Information System (INIS)

    Kiesel, Maximilian Ludwig

    2013-01-01

    A general theory for all classes of unconventional superconductors is still one of the unsolved key issues in condensed-matter physics. Actually, it is not yet fully settled if there is a common underlying pairing mechanism. Instead, it might be possible that several distinct sources for unconventional (not phonon-mediated) superconductivity have to be considered, or an electron-phonon interaction is not negligible. The focus of this thesis is on the most probable mechanism for the formation of Cooper pairs in unconventional superconductors, namely a strictly electronic one where spin fluctuations are the mediators. Studying different superconductors in this thesis, the emphasis is put on material-independent features of the pairing mechanism. In addition, the investigation of the phase diagrams enables a view on the vicinity of superconductivity. Thus, it is possible to clarify which competing quantum fluctuations enhance or weaken the propensity for a superconducting state. The broad range of superconducting materials requires the use of more than one numerical technique to study an appropriate microscopic description. This is not a problem but a big advantage because this facilitates the approach-independent description of common underlying physics. For this evaluation, the strongly correlated cuprates are simulated with the variational cluster approach. Especially the question of a pairing glue is taken into consideration. Furthermore, it is possible to distinguish between retarded and non-retarded contributions to the gap function. The cuprates are confronted with the cobaltate Na x CoO 2 and graphene. These weakly correlated materials are investigated with the functional renormalization group (fRG) and reveal a comprehensive phase diagram, including a d+id-wave superconductivity, which breaks time-reversal symmetry. The corresponding gap function is nodeless, but for NaCoO, it features a doping-dependent anisotropy. In addition, some general considerations on

  5. Unconventional superconductivity in cuprates, cobaltates and graphene. What is universal and what is material-dependent in strongly versus weakly correlated materials?

    Energy Technology Data Exchange (ETDEWEB)

    Kiesel, Maximilian Ludwig

    2013-02-08

    A general theory for all classes of unconventional superconductors is still one of the unsolved key issues in condensed-matter physics. Actually, it is not yet fully settled if there is a common underlying pairing mechanism. Instead, it might be possible that several distinct sources for unconventional (not phonon-mediated) superconductivity have to be considered, or an electron-phonon interaction is not negligible. The focus of this thesis is on the most probable mechanism for the formation of Cooper pairs in unconventional superconductors, namely a strictly electronic one where spin fluctuations are the mediators. Studying different superconductors in this thesis, the emphasis is put on material-independent features of the pairing mechanism. In addition, the investigation of the phase diagrams enables a view on the vicinity of superconductivity. Thus, it is possible to clarify which competing quantum fluctuations enhance or weaken the propensity for a superconducting state. The broad range of superconducting materials requires the use of more than one numerical technique to study an appropriate microscopic description. This is not a problem but a big advantage because this facilitates the approach-independent description of common underlying physics. For this evaluation, the strongly correlated cuprates are simulated with the variational cluster approach. Especially the question of a pairing glue is taken into consideration. Furthermore, it is possible to distinguish between retarded and non-retarded contributions to the gap function. The cuprates are confronted with the cobaltate Na{sub x}CoO{sub 2} and graphene. These weakly correlated materials are investigated with the functional renormalization group (fRG) and reveal a comprehensive phase diagram, including a d+id-wave superconductivity, which breaks time-reversal symmetry. The corresponding gap function is nodeless, but for NaCoO, it features a doping-dependent anisotropy. In addition, some general

  6. A High-Pressure Study of Manganese Metal and its Reactions with CO2 at 6, 23, and 44 GPa

    Science.gov (United States)

    Sawchuk, K. L. S.; McGuire, C. P.; Greenburg, A.; Makhluf, A.; Kavner, A.

    2017-12-01

    The free energies of formation of oxides and carbonates at the extreme pressures and temperatures of Earth's interior provides some of the thermodynamic constrains for models of mantle/core formation and subsequent chemical evolution. The broad goal of our research program is to measure the pressure- and temperature-dependence of free energies of formation of transition metal oxides and carbonates. This requires measurements of the phase stability, density, and thermoelastic properties of metals, oxides, and carbonates at deep-Earth and planetary conditions. Manganese is of interest because it is one of the most abundant transition metal geochemical tracers, it readily forms a carbonate at ambient pressure, and its high-pressure carbonate and oxide densities and equation of state parameters are relatively unknown. Here we report new data on the pressure/volume equation of state and structure of manganese metal as well as its reactions with CO2. These measurements were made using a laser heated diamond anvil cell in conjunction with synchrotron-based X-ray diffraction at beamline 12.2.2 at the Advanced Light Source. Three samples of manganese metal were gas-loaded in a CO2 pressure medium and pressurized to 6, 23, and 44 GPa. Upon laser heating, the CO2 reacted with the Mn metal generating new phases. To analyze the diffraction patterns, we we use a python-based program developed in-house for extracting high resolution 2-dimensional diffraction peak position and intensity information from two-dimensional X-ray diffraction patterns. At each pressure step, the structure and density of the quenched Mn metal phase was determined. At 6 GPa, Mn metal adopts a BCC structure, and at 23 GPa a tetragonal distortion is observed in the lattice. The measured equation of state is in good agreement with an existing meaurement by Fujihisa and Takemura (1995). MnCO3 rhodochrosite is observed in the sample quenched after heating at 6 GPa. Additional high pressure phases are evident

  7. X-ray diffraction study of elemental erbium to 70 GPa

    International Nuclear Information System (INIS)

    Pravica, Michael G.; Romano, Edward; Quine, Zachary

    2005-01-01

    We have investigated phase transitions in elemental erbium in a diamond anvil cell (DAC) up to 70 GPa using angular-dispersive x-ray powder diffraction methods. We present evidence of a series of phase transitions that appear to follow the anticipated hcp→Sm-type→double hcp (dhcp)→distorted fcc sequence. In particular, we present evidence for the predicted dhcp→distorted fcc transition above 63 GPa. Equation of state data are also presented up to 70 GPa

  8. Optical emission, shock-induced opacity, temperatures, and melting of Gd3Ga5O12 single crystals shock-compressed from 41 to 290 GPa

    Science.gov (United States)

    Zhou, Xianming; Nellis, William J.; Li, Jiabo; Li, Jun; Zhao, Wanguang; Liu, Xun; Cao, Xiuxia; Liu, Qiancheng; Xue, Tao; Wu, Qiang; Mashimo, T.

    2015-08-01

    Strong oxides at high shock pressures have broad crossovers from elastic solids at ambient to failure by plastic deformation, to heterogeneous deformation to weak solids, to fluid-like solids that equilibrate thermally in a few ns, to melting and, at sufficiently high shock pressures and temperatures, to metallic fluid oxides. This sequence of crossovers in single-crystal cubic Gd3Ga5O12 (Gd-Ga Garnet-GGG) has been diagnosed by fast emission spectroscopy using a 16-channel optical pyrometer in the spectral range 400-800 nm with bandwidths per channel of 10 nm, a writing time of ˜1000 ns and time resolution of 3 ns. Spectra were measured at shock pressures from 40 to 290 GPa (100 GPa = 1 Mbar) with corresponding gray-body temperatures from 3000 to 8000 K. Experimental lifetimes were a few 100 ns. Below 130 GPa, emission is heterogeneous and measured temperatures are indicative of melting temperatures in grain boundary regions rather than bulk temperatures. At 130 GPa and 2200 K, GGG equilibrates thermally and homogeneously in a thin opaque shock front. This crossover has a characteristic spectral signature in going from partially transmitting shock-heated material behind the shock front to an opaque shock front. Opacity is caused by optical scattering and absorption of light generated by fast compression. GGG melts at ˜5000 K in a two-phase region at shock pressures in the range 200 GPa to 217 GPa. Hugoniot equation-of-state data were measured by a Doppler Pin SystemDPS with ps time resolution and are generally consistent with previous data. Extrapolation of previous electrical conductivity measurements indicates that GGG becomes a poor metal at a shock pressure above ˜400 GPa. Because the shock impedance of GGG is higher than that of Al2O3 used previously to make metallic fluid H (MFH), the use of GGG to make MFH will achieve higher pressures and lower temperatures than use of Al2O3. However, maximum dynamic pressures at which emission temperatures of fluid

  9. 48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL... 25.504-2 WTO GPA/Caribbean Basin Trade Initiative/FTAs. Example 1. Offer A 304,000 U.S.-made end...

  10. 40 CFR 80.217 - How does a refiner or importer apply for the GPA standards?

    Science.gov (United States)

    2010-07-01

    ... annual average sulfur standard for gasoline produced for use in the GPA for the 2004 through 2006 annual... for gasoline produced for use in the GPA. (d) If EPA finds that a refiner or importer provided false... (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase...

  11. Interpreting the Relationships between TOEFL iBT Scores and GPA: Language Proficiency, Policy, and Profiles

    Science.gov (United States)

    Ginther, April; Yan, Xun

    2018-01-01

    This study examines the predictive validity of the TOEFL iBT with respect to academic achievement as measured by the first-year grade point average (GPA) of Chinese students at Purdue University, a large, public, Research I institution in Indiana, USA. Correlations between GPA, TOEFL iBT total and subsection scores were examined on 1990 mainland…

  12. The grain size dependency of vesicular particle shapes strongly affects the drag of particles. First results from microtomography investigations of Campi Flegrei fallout deposits

    Science.gov (United States)

    Mele, Daniela; Dioguardi, Fabio

    2018-03-01

    Acknowledging the grain size dependency of shape is important in volcanology, in particular when dealing with tephra produced and emplaced during and after explosive volcanic eruptions. A systematic measurement of the tridimensional shape of vesicular pyroclasts of Campi Flegrei fallout deposits (Agnano-Monte Spina, Astroni 6 and Averno 2 eruptions) varying in size from 8.00 to 0.016 mm has been carried out by means of X-Ray Microtomography. Data show that particle shape changes with size, especially for juvenile vesicular clasts, since it is dependent on the distribution and size of vesicles that contour the external clast outline. Two drag laws that include sphericity in the formula were used for estimating the dependency of settling velocity on shape. Results demonstrate that it is not appropriate to assume a size-independent shape for vesicular particles, in contrast with the approach commonly employed when simulating the ash dispersion in the atmosphere.

  13. Structure of sodium above 100 GPa by single-crystal x-ray diffraction.

    Science.gov (United States)

    McMahon, M I; Gregoryanz, E; Lundegaard, L F; Loa, I; Guillaume, C; Nelmes, R J; Kleppe, A K; Amboage, M; Wilhelm, H; Jephcoat, A P

    2007-10-30

    At pressures above a megabar (100 GPa), sodium crystallizes in a number of complex crystal structures with unusually low melting temperatures, reaching as low as 300 K at 118 GPa. We have utilized this unique behavior at extreme pressures to grow a single crystal of sodium at 108 GPa, and have investigated the complex crystal structure at this pressure using high-intensity x-rays from the new Diamond synchrotron source, in combination with a pressure cell with wide angular apertures. We confirm that, at 108 GPa, sodium is isostructural with the cI16 phase of lithium, and we have refined the full crystal structure of this phase. The results demonstrate the extension of single-crystal structure refinement beyond 100 GPa and raise the prospect of successfully determining the structures of yet more complex phases reported in sodium and other elements at extreme pressures.

  14. Outcome of Treatment of Human HeLa Cervical Cancer Cells With Roscovitine Strongly Depends on the Dosage and Cell Cycle Status Prior to the Treatment

    Czech Academy of Sciences Publication Activity Database

    Wesierska-Gadek, J.; Borza, A.; Walzi, E.; Kryštof, Vladimír; Maurer, M.; Komina, O.; Wandl, S.

    2009-01-01

    Roč. 106, č. 5 (2009), s. 937-955 ISSN 0730-2312 Institutional research plan: CEZ:AV0Z50380511 Keywords : APOPTOSIS * CELL CYCLE ARREST * CYCLIN-DEPENDENT KINASES Subject RIV: ED - Physiology Impact factor: 2.935, year: 2009

  15. PsHint1, associated with the G-protein α subunit PsGPA1, is required for the chemotaxis and pathogenicity of Phytophthora sojae.

    Science.gov (United States)

    Zhang, Xin; Zhai, Chunhua; Hua, Chenlei; Qiu, Min; Hao, Yujuan; Nie, Pingping; Ye, Wenwu; Wang, Yuanchao

    2016-02-01

    Zoospore chemotaxis to soybean isoflavones is essential in the early stages of infection by the oomycete pathogen Phytophthora sojae. Previously, we have identified a G-protein α subunit encoded by PsGPA1 which regulates the chemotaxis and pathogenicity of P. sojae. In the present study, we used affinity purification to identify PsGPA1-interacting proteins, including PsHint1, a histidine triad (HIT) domain-containing protein orthologous to human HIT nucleotide-binding protein 1 (HINT1). PsHint1 interacted with both the guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms of PsGPA1. An analysis of the gene-silenced transformants revealed that PsHint1 was involved in the chemotropic response of zoospores to the isoflavone daidzein. During interaction with a susceptible soybean cultivar, PsHint1-silenced transformants displayed significantly reduced infectious hyphal extension and caused a strong cell death in plants. In addition, the transformants displayed defective cyst germination, forming abnormal germ tubes that were highly branched and exhibited apical swelling. These results suggest that PsHint1 not only regulates chemotaxis by interacting with PsGPA1, but also participates in a Gα-independent pathway involved in the pathogenicity of P. sojae. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  16. Dye concentration dependence of spectral triplet in one-dimensional photonic crystal with cyanine dye J-aggregate in strong coupling regime

    Science.gov (United States)

    Suzuki, Makoto; Sakata, Tomohiro; Takenobu, Ryouya; Uemura, Shinobu; Miyagawa, Hayato; Nakanishi, Shunsuke; Tsurumachi, Noriaki

    2017-10-01

    We report on the dye concentration dependence of nonlinear transmission properties of one-dimensional photonic crystal microcavities containing cyanine dye J-aggregates. Using femtosecond nonlinear transmission spectroscopy, we observed a transition from a polariton doublet state to a spectral triplet state over the whole tested concentration range, even at room temperature. In these samples, changes in the dye concentration affected the Rabi splitting energy in the linear transmission measurements; however, we found that changes in the concentration did not greatly affect the triplet formation.

  17. Strong dependence of a pioneer shrub on seed dispersal services provided by an endemic endangered lizard in a Mediterranean island ecosystem.

    Science.gov (United States)

    Neghme, Constanza; Santamaría, Luís; Calviño-Cancela, María

    2017-01-01

    The accelerating rate of vertebrate extinctions and population declines threatens to disrupt important ecological interactions, altering key ecosystem processes such as animal seed dispersal. The study of highly specialized mutualistic interactions is crucial to predict the consequences of population declines and extinctions. Islands offer unique opportunities to study highly specialized interactions, as they often have naturally depauperated faunas and are experiencing high rates of human-driven extinctions. In this study, we assess the effect of seed dispersal on seedling recruitment of Ephedra fragilis (Ephedraceae) on a Mediterranean island ecosystem. We used field data and stochastic simulation modeling to estimate seed fate and recruitment patterns of this pioneer shrub typical of arid and semiarid areas, and to estimate the dependence of recruitment on the lizard Podarcis lilfordi (Lacertidae), its only known seed disperser. Ephedra fragilis recruitment highly depended on lizards: lizards produced 3.8 times more newly-emerged seedlings than non-dispersed seeds and no seedlings from undispersed seeds survived the study period. Seed dispersal by lizards was mostly to open sites, which was key for the increased success observed, while undispersed seeds, falling under mother plants, suffered higher predation and lower seedling emergence and survival. The ability of this pioneer shrub to get established in open ground is crucial for vegetation colonization and restoration, especially on degraded lands affected by desertification, where they act as nurse plants for other species. Lizards are key in this process, which has important consequences for community structure and ecosystem functioning.

  18. Unitary Dynamics of Strongly Interacting Bose Gases with the Time-Dependent Variational Monte Carlo Method in Continuous Space

    Directory of Open Access Journals (Sweden)

    Giuseppe Carleo

    2017-08-01

    Full Text Available We introduce the time-dependent variational Monte Carlo method for continuous-space Bose gases. Our approach is based on the systematic expansion of the many-body wave function in terms of multibody correlations and is essentially exact up to adaptive truncation. The method is benchmarked by comparison to an exact Bethe ansatz or existing numerical results for the integrable Lieb-Liniger model. We first show that the many-body wave function achieves high precision for ground-state properties, including energy and first-order as well as second-order correlation functions. Then, we study the out-of-equilibrium, unitary dynamics induced by a quantum quench in the interaction strength. Our time-dependent variational Monte Carlo results are benchmarked by comparison to exact Bethe ansatz results available for a small number of particles, and are also compared to quench action results available for noninteracting initial states. Moreover, our approach allows us to study large particle numbers and general quench protocols, previously inaccessible beyond the mean-field level. Our results suggest that it is possible to find correlated initial states for which the long-term dynamics of local density fluctuations is close to the predictions of a simple Boltzmann ensemble.

  19. Compressive strength measurements in aluminum for shock compression over the stress range of 4-22 GPa

    Science.gov (United States)

    Huang, H.; Asay, J. R.

    2005-08-01

    Measurements of the high-pressure compressive strength are presented for several aluminum alloys shocked to 22GPa. Five well-characterized aluminum materials were studied, including 6061 alloy with three average grain sizes (50, 30, and strength varies with initial properties. The yield strength was estimated using combined reshock and release techniques previously developed. These results show that quasielastic recompression occurs for all materials investigated and is independent of grain size and impurity level. The shear stress and the shear strength at the shocked state were estimated from the reshock and release wave profiles. These results are consistent with previous investigations and suggest that the shear stress at the Hugoniot state is less than the yield strength. This is thought responsible for the observed quasielastic recompression. The present data, together with other reported measurements, illustrate that the yield strength of aluminum increases with applied shock stress to 90GPa. The Steinberg-Guinan strength model [Steinberg, Cochran, and Guinan, J. Appl. Phys. 51, 1498 (1980)] was used to describe these data and was found to represent the overall data trend with increasing stress, but is not an accurate representation. The collective data suggest that the increase in strength at shock states, ΔY(ΔY =Yyield-YHEL), increases with applied stress and plastic strain. A strength model was developed to describe this increase, which fits the data accurately to 55GPa and reveals that ΔY increases with shock stress in three distinct regions. It also strongly indicates that metallurgical properties, such as impurities and grain size, influence the ambient yield strength, but not the change in strength, which appears to be controlled by the shock-deformed aluminum matrix and possibly grain boundaries.

  20. Nanocrystal Size-Dependent Efficiency of Quantum Dot Sensitized Solar Cells in the Strongly Coupled CdSe Nanocrystals/TiO2 System.

    Science.gov (United States)

    Yun, Hyeong Jin; Paik, Taejong; Diroll, Benjamin; Edley, Michael E; Baxter, Jason B; Murray, Christopher B

    2016-06-15

    Light absorption and electron injection are important criteria determining solar energy conversion efficiency. In this research, monodisperse CdSe quantum dots (QDs) are synthesized with five different diameters, and the size-dependent solar energy conversion efficiency of CdSe quantum dot sensitized solar cell (QDSSCs) is investigated by employing the atomic inorganic ligand, S(2-). Absorbance measurements and transmission electron microscopy show that the diameters of the uniform CdSe QDs are 2.5, 3.2, 4.2, 6.4, and 7.8 nm. Larger CdSe QDs generate a larger amount of charge under the irradiation of long wavelength photons, as verified by the absorbance results and the measurements of the external quantum efficiencies. However, the smaller QDs exhibit faster electron injection kinetics from CdSe QDs to TiO2 because of the high energy level of CBCdSe, as verified by time-resolved photoluminescence and internal quantum efficiency results. Importantly, the S(2-) ligand significantly enhances the electronic coupling between the CdSe QDs and TiO2, yielding an enhancement of the charge transfer rate at the interfacial region. As a result, the S(2-) ligand helps improve the new size-dependent solar energy conversion efficiency, showing best performance with 4.2-nm CdSe QDs, whereas conventional ligand, mercaptopropionic acid, does not show any differences in efficiency according to the size of the CdSe QDs. The findings reported herein suggest that the atomic inorganic ligand reinforces the influence of quantum confinement on the solar energy conversion efficiency of QDSSCs.

  1. High night temperature strongly impacts TCA cycle, amino acid and polyamine biosynthetic pathways in rice in a sensitivity-dependent manner.

    Science.gov (United States)

    Glaubitz, Ulrike; Erban, Alexander; Kopka, Joachim; Hincha, Dirk K; Zuther, Ellen

    2015-10-01

    Global climate change combined with asymmetric warming can have detrimental effects on the yield of crop plants such as rice (Oryza sativa L.). Little is known about metabolic responses of rice to high night temperature (HNT) conditions. Twelve cultivars with different HNT sensitivity were used to investigate metabolic changes in the vegetative stage under HNT compared to control conditions. Central metabolism, especially TCA cycle and amino acid biosynthesis, were strongly affected particularly in sensitive cultivars. Levels of several metabolites were correlated with HNT sensitivity. Furthermore, pool sizes of some metabolites negatively correlated with HNT sensitivity under control conditions, indicating metabolic pre-adaptation in tolerant cultivars. The polyamines putrescine, spermidine and spermine showed increased abundance in sensitive cultivars under HNT conditions. Correlations between the content of polyamines and 75 other metabolites indicated metabolic shifts from correlations with sugar-phosphates and 1-kestose under control to correlations with sugars and amino and organic acids under HNT conditions. Increased expression levels of ADC2 and ODC1, genes encoding enzymes catalysing the first committed steps of putrescine biosynthesis, were restricted to sensitive cultivars under HNT. Additionally, transcript levels of eight polyamine biosynthesis genes were correlated with HNT sensitivity. Responses to HNT in the vegetative stage result in distinct differences between differently responding cultivars with a dysregulation of central metabolism and an increase of polyamine biosynthesis restricted to sensitive cultivars under HNT conditions and a pre-adaptation of tolerant cultivars already under control conditions with higher levels of potentially protective compatible solutes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Decrypting Strong and Weak Single-Walled Carbon Nanotubes Interactions with Mitochondrial Voltage-Dependent Anion Channels Using Molecular Docking and Perturbation Theory.

    Science.gov (United States)

    González-Durruthy, Michael; Werhli, Adriano V; Seus, Vinicius; Machado, Karina S; Pazos, Alejandro; Munteanu, Cristian R; González-Díaz, Humberto; Monserrat, José M

    2017-10-16

    The current molecular docking study provided the Free Energy of Binding (FEB) for the interaction (nanotoxicity) between VDAC mitochondrial channels of three species (VDAC1-Mus musculus, VDAC1-Homo sapiens, VDAC2-Danio rerio) with SWCNT-H, SWCNT-OH, SWCNT-COOH carbon nanotubes. The general results showed that the FEB values were statistically more negative (p  (SWCNT-VDAC1-Mus musculus) > (SWCNT-VDAC1-Homo sapiens) > (ATP-VDAC). More negative FEB values for SWCNT-COOH and OH were found in VDAC2-Danio rerio when compared with VDAC1-Mus musculus and VDAC1-Homo sapiens (p  r 2  > 0.97) was observed between n-Hamada index and VDAC nanotoxicity (or FEB) for the zigzag topologies of SWCNT-COOH and SWCNT-OH. Predictive Nanoparticles-Quantitative-Structure Binding-Relationship models (nano-QSBR) for strong and weak SWCNT-VDAC docking interactions were performed using Perturbation Theory, regression and classification models. Thus, 405 SWCNT-VDAC interactions were predicted using a nano-PT-QSBR classifications model with high accuracy, specificity, and sensitivity (73-98%) in training and validation series, and a maximum AUROC value of 0.978. In addition, the best regression model was obtained with Random Forest (R 2 of 0.833, RMSE of 0.0844), suggesting an excellent potential to predict SWCNT-VDAC channel nanotoxicity. All study data are available at https://doi.org/10.6084/m9.figshare.4802320.v2 .

  3. Light- and pH-dependent conformational changes in protein structure induce strong bending of purple membranes--active membranes studied by cryo-SEM.

    Science.gov (United States)

    Rhinow, Daniel; Hampp, Norbert A

    2008-10-16

    Bacteriorhodopsin (BR) undergoes a conformational change during the photocycle and the proton transport through the membrane. For the first time, we could demonstrate by direct imaging of freely suspended native purple membranes (PMs) that the flat disk-like shape of PMs changes dramatically as soon as most of the BRs are in a state characterized by a deprotonated Schiff base. Light-induced shape changes are easily observed with mutated BRs of the BR-D96N type, i.e., all variants which show an increased M 2 lifetime. On the other hand, large-scale shape changes are induced by pH changes with PM containing mutated BRs of the BR-D85T type, where Asp85 is replaced for a neutral amino acid. In such PMs, all BRs are titrated simultaneously and the resulting shape of the membranes depends on the initial shape only. As the majority of PMs in the "flat" state are more or less round disks, the bent membranes often comprise bowl-like and tube-like bent structures. The method presented here enables one to derive size changes of membrane-embedded BRs on the single molecule level from "macroscopic", easily accessible data like the curvature radii observed in cryo-SEM. The potential of BR as a pH-controlled and/or light-controlled microscaled biological actuator needs further consideration.

  4. Radial X-ray diffraction study of the static strength and texture of tungsten to 96 GPa

    Science.gov (United States)

    Xiong, Lun; Li, Bin; Tang, Yumei; Li, Qiang; Hao, Jiabo; Bai, Ligang; Li, Xiaodong; Liu, Jing

    2018-01-01

    Investigations of equation of state, strength and texture of tungsten (W) have been performed under nonhydrostatic compression up to 96 GPa using an angle-dispersive radial X-ray diffraction (RXRD) techniques together with the lattice strain theory in a 2-fold paranomic diamond anvil cell (DAC) at ambient temperature. The ratio of t/G is found to remain constant above ∼35 GPa, indicating that the W started to experience macro yield with plastic deformation at this pressure. Combined with independent constraints on the high-pressure shear modulus, we found that W sample could support a differential stress of ∼4.57 GPa when it started to yield with plastic deformation at ∼35 GPa under uniaxial compression. The differential stress in W ranges from 0.01 GPa to 1.46 GPa with pressure increasing from 6 GPa to 35 GPa and can be described as t = -0.904(136) + 0.154(6)P, where P is the pressure in GPa. A maximum differential stress, as high as ∼6.46 GPa can be supported by W at the highest pressure of ∼96 GPa. In addition, we have investigated the texture of W under nonhydrostatic compression up to the highest pressure of 96 GPa using the software package MAUD (Material Analysis Using Diffraction). It is convinced that the plastic deformation due to stress under high pressures is responsible for the development of texture.

  5. HER2 signaling pathway activation and response of breast cancer cells to HER2-targeting agents is dependent strongly on the 3D microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Weigelt, Britta; Lo, Alvin T; Park, Catherine C; Gray, Joe W; Bissell, Mina J

    2009-07-27

    Development of effective and durable breast cancer treatment strategies requires a mechanistic understanding of the influence of the microenvironment on response. Previous work has shown that cellular signaling pathways and cell morphology are dramatically influenced by three-dimensional (3D) cultures as opposed to traditional two-dimensional (2D) monolayers. Here, we compared 2D and 3D culture models to determine the impact of 3D architecture and extracellular matrix (ECM) on HER2 signaling and on the response of HER2-amplified breast cancer cell lines to the HER2-targeting agents Trastuzumab, Pertuzumab and Lapatinib. We show that the response of the HER2-amplified AU565, SKBR3 and HCC1569 cells to these anti-HER2 agents was highly dependent on whether the cells were cultured in 2D monolayer or 3D laminin-rich ECM gels. Inhibition of {beta}1 integrin, a major cell-ECM receptor subunit, significantly increased the sensitivity of the HER2-amplified breast cancer cell lines to the humanized monoclonal antibodies Trastuzumab and Pertuzumab when grown in a 3D environment. Finally, in the absence of inhibitors, 3D cultures had substantial impact on HER2 downstream signaling and induced a switch between PI3K-AKT- and RAS-MAPKpathway activation in all cell lines studied, including cells lacking HER2 amplification and overexpression. Our data provide direct evidence that breast cancer cells are able to rapidly adapt to different environments and signaling cues by activating alternative pathways that regulate proliferation and cell survival, events that may play a significant role in the acquisition of resistance to targeted therapies.

  6. HER2 signaling pathway activation and response of breast cancer cells to HER2-targeting agents is dependent strongly on the 3D microenvironment.

    Science.gov (United States)

    Weigelt, Britta; Lo, Alvin T; Park, Catherine C; Gray, Joe W; Bissell, Mina J

    2010-07-01

    Development of effective and durable breast cancer treatment strategies requires a mechanistic understanding of the influence of the microenvironment on response. Previous work has shown that cellular signaling pathways and cell morphology are dramatically influenced by three-dimensional (3D) cultures as opposed to traditional two-dimensional (2D) monolayers. Here, we compared 2D and 3D culture models to determine the impact of 3D architecture and extracellular matrix (ECM) on HER2 signaling and on the response of HER2-amplified breast cancer cell lines to the HER2-targeting agents Trastuzumab, Pertuzumab and Lapatinib. We show that the response of the HER2-amplified AU565, SKBR3 and HCC1569 cells to these anti-HER2 agents was highly dependent on whether the cells were cultured in 2D monolayer or 3D laminin-rich ECM gels. Inhibition of beta1 integrin, a major cell-ECM receptor subunit, significantly increased the sensitivity of the HER2-amplified breast cancer cell lines to the humanized monoclonal antibodies Trastuzumab and Pertuzumab when grown in a 3D environment. Finally, in the absence of inhibitors, 3D cultures had substantial impact on HER2 downstream signaling and induced a switch between PI3K-AKT- and RAS-MAPK-pathway activation in all cell lines studied, including cells lacking HER2 amplification and overexpression. Our data provide direct evidence that breast cancer cells are able to rapidly adapt to different environments and signaling cues by activating alternative pathways that regulate proliferation and cell survival, events that may play a significant role in the acquisition of resistance to targeted therapies.

  7. Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 GPa

    Directory of Open Access Journals (Sweden)

    JianJun Jiang

    2016-03-01

    Full Text Available The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC, to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E 2 g 1 ,A1g, and 2LA(M. Over our experimental temperature and pressure range (300–600 K and 1 atm−18.5 GPa, the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3–4 GPa lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.

  8. Caffeine Consumption among Medical Interns and Association with GPA in Makkah Region

    Directory of Open Access Journals (Sweden)

    Alsharif Mohammed H

    2016-12-01

    Full Text Available The Vagarious amount of caffeine may become harmful in frequent use, it increased among medical interns in Makkah region. The caffeine becomes a daily routine for medical interns without attention for their side harmful effect. The purpose of our study was to evaluate the educational level of awareness of the harmful effect of caffeine consumption. This was a cross-sectional study from August to October 2016. A total number 437 of participants with GPA groups, Group I (GPA 1.5-2, Group II (GPA 2.1- 3 and Group III (GPA 3.1- 3.5. The higher percentages were the group II and female consumed caffeine frequently more than male.

  9. Overexpression of KIR inhibitory ligands (HLA-I) determines that immunosurveillance of myeloma depends on diverse and strong NK cell licensing.

    Science.gov (United States)

    Martínez-Sánchez, María V; Periago, Adela; Legaz, Isabel; Gimeno, Lourdes; Mrowiec, Anna; Montes-Barqueros, Natividad R; Campillo, José A; Bolarin, José M; Bernardo, María V; López-Álvarez, María R; González, Consuelo; García-Garay, María C; Muro, Manuel; Cabañas-Perianes, Valentin; Fuster, Jose L; García-Alonso, Ana M; Moraleda, José M; Álvarez-Lopez, María R; Minguela, Alfredo

    2016-04-01

    -missing-self cancers, e.g., myeloma, mainly depends on NKc licensing.

  10. Stability of Carbonated Eclogite in the Upper Mantle: Experimental Solidus from 2 to 9 GPa

    Science.gov (United States)

    Dasgupta, R.; Withers, A. C.; Hirschmann, M. M.

    2003-12-01

    Carbonates are pervasive alteration products of the oceanic crust and likely survive subduction-related dehydration and/or melting. Thus, significant quantities of carbonated refractory eclogite are probably delivered to the deeper mantle. The melting behavior of such recycled carbonate influences the fate of recycled carbon, determines the possible sources and depths of carbonated metasomatic melts in the mantle, and delimits the conditions under which carbonated eclogite may act as a source of carbonatite and other types of magmatic CO2. We present partial melting experiments of carbonated eclogite that constrain the solidus and near solidus phase relations from 2 to 9 GPa. To simulate the near-isochemical nature of ocean floor carbonation, the starting material was prepared by adding 5 wt.% CO2 in the form of a mixture of Fe-Mg-Ca-Na-K carbonates to a bimineralic eclogite from Salt Lake crater, Oahu, Hawaii. The starting composition is a reasonable approximation of carbonated oceanic crust from which siliceous hydrous fluid has been extracted by subduction. We find that melt-present versus melt-absent conditions can be distinguished based on textural criteria. Garnet and cpx appear in all the experiments. Between 2 and 3 GPa, the subsolidus assemblage also includes calcite-dolomitess + ilmenite, whereas above the solidus (950-975 ° C at 2 GPa and 1050-1075 ° C at 3 GPa) calcio-dolomitic liquid appears. From 3 to 4.5 GPa, dolomitess becomes stable at the solidus and the near solidus melt becomes increasingly dolomitic. Appearance of dolomite above 3 GPa is accompanied by a negative Clapeyron slope of the solidus, with the cusp located between 995 and 1025 ° C at ca. 4 GPa. Above 4-4.5 GPa, the solidus again rises with increasing pressure to ca. 1245 ° C at 9 GPa and magnesite becomes the subsolidus carbonate. Dolomitic melt coexists with magnesite + garnet + cpx + rutile between 5 and 9 GPa. If extrapolated to higher pressures, the carbonated eclogite solidus

  11. GPA: a statistical approach to prioritizing GWAS results by integrating pleiotropy and annotation.

    Directory of Open Access Journals (Sweden)

    Dongjun Chung

    2014-11-01

    Full Text Available Results from Genome-Wide Association Studies (GWAS have shown that complex diseases are often affected by many genetic variants with small or moderate effects. Identifications of these risk variants remain a very challenging problem. There is a need to develop more powerful statistical methods to leverage available information to improve upon traditional approaches that focus on a single GWAS dataset without incorporating additional data. In this paper, we propose a novel statistical approach, GPA (Genetic analysis incorporating Pleiotropy and Annotation, to increase statistical power to identify risk variants through joint analysis of multiple GWAS data sets and annotation information because: (1 accumulating evidence suggests that different complex diseases share common risk bases, i.e., pleiotropy; and (2 functionally annotated variants have been consistently demonstrated to be enriched among GWAS hits. GPA can integrate multiple GWAS datasets and functional annotations to seek association signals, and it can also perform hypothesis testing to test the presence of pleiotropy and enrichment of functional annotation. Statistical inference of the model parameters and SNP ranking is achieved through an EM algorithm that can handle genome-wide markers efficiently. When we applied GPA to jointly analyze five psychiatric disorders with annotation information, not only did GPA identify many weak signals missed by the traditional single phenotype analysis, but it also revealed relationships in the genetic architecture of these disorders. Using our hypothesis testing framework, statistically significant pleiotropic effects were detected among these psychiatric disorders, and the markers annotated in the central nervous system genes and eQTLs from the Genotype-Tissue Expression (GTEx database were significantly enriched. We also applied GPA to a bladder cancer GWAS data set with the ENCODE DNase-seq data from 125 cell lines. GPA was able to detect cell

  12. Density-driven structural transformations in network forming glasses: a high-pressure neutron diffraction study of GeO2 glass up to 17.5 GPa.

    Science.gov (United States)

    Salmon, Philip S; Drewitt, James W E; Whittaker, Dean A J; Zeidler, Anita; Wezka, Kamil; Bull, Craig L; Tucker, Matthew G; Wilding, Martin C; Guthrie, Malcolm; Marrocchelli, Dario

    2012-10-17

    The structure of GeO(2) glass was investigated at pressures up to 17.5(5) GPa using in situ time-of-flight neutron diffraction with a Paris-Edinburgh press employing sintered diamond anvils. A new methodology and data correction procedure were developed, enabling a reliable measurement of structure factors that are largely free from diamond Bragg peaks. Calibration curves, which are important for neutron diffraction work on disordered materials, were constructed for pressure as a function of applied load for both single and double toroid anvil geometries. The diffraction data are compared to new molecular-dynamics simulations made using transferrable interaction potentials that include dipole-polarization effects. The results, when taken together with those from other experimental methods, are consistent with four densification mechanisms. The first, at pressures up to approximately equal 5 GPa, is associated with a reorganization of GeO(4) units. The second, extending over the range from approximately equal 5 to 10 GPa, corresponds to a regime where GeO(4) units are replaced predominantly by GeO(5) units. In the third, as the pressure increases beyond ~10 GPa, appreciable concentrations of GeO(6) units begin to form and there is a decrease in the rate of change of the intermediate-range order as measured by the pressure dependence of the position of the first sharp diffraction peak. In the fourth, at about 30 GPa, the transformation to a predominantly octahedral glass is achieved and further densification proceeds via compression of the Ge-O bonds. The observed changes in the measured diffraction patterns for GeO(2) occur at similar dimensionless number densities to those found for SiO(2), indicating similar densification mechanisms for both glasses. This implies a regime from about 15 to 24 GPa where SiO(4) units are replaced predominantly by SiO(5) units, and a regime beyond ~24 GPa where appreciable concentrations of SiO(6) units begin to form.

  13. GPA-MDS: A Visualization Approach to Investigate Genetic Architecture among Phenotypes Using GWAS Results.

    Science.gov (United States)

    Wei, Wei; Ramos, Paula S; Hunt, Kelly J; Wolf, Bethany J; Hardiman, Gary; Chung, Dongjun

    2016-01-01

    Genome-wide association studies (GWAS) have identified tens of thousands of genetic variants associated with hundreds of phenotypes and diseases, which have provided clinical and medical benefits to patients with novel biomarkers and therapeutic targets. Recently, there has been accumulating evidence suggesting that different complex traits share a common risk basis, namely, pleiotropy. Previously, a statistical method, namely, GPA (Genetic analysis incorporating Pleiotropy and Annotation), was developed to improve identification of risk variants and to investigate pleiotropic structure through a joint analysis of multiple GWAS datasets. While GPA provides a statistically rigorous framework to evaluate pleiotropy between phenotypes, it is still not trivial to investigate genetic relationships among a large number of phenotypes using the GPA framework. In order to address this challenge, in this paper, we propose a novel approach, GPA-MDS, to visualize genetic relationships among phenotypes using the GPA algorithm and multidimensional scaling (MDS). This tool will help researchers to investigate common etiology among diseases, which can potentially lead to development of common treatments across diseases. We evaluate the proposed GPA-MDS framework using a simulation study and apply it to jointly analyze GWAS datasets examining 18 unique phenotypes, which helps reveal the shared genetic architecture of these phenotypes.

  14. The electric field gradient at 111Cd in ZrZn2 in the samples prepared at 8 GPa

    International Nuclear Information System (INIS)

    Sorokin, A.A.; Ryasny, G.K.; Komissarova, B.A.; Tsvyashchenko, A.V.; Fomichova, L.N.

    2005-01-01

    Full text: The perturbed angular correlation (PAC) measurements with the 111 In- 111 Cd nuclear probe embedded into the lattice of the cubic (C15) Laves compound in ZrZn 2 showed that 111 Cd nuclei experienced an axially symmetric electric quadrupole interaction with a frequency v Q = 133.7 MHz at room temperature. The samples were synthesized and doped with the probe at a pressure 8 GPa. The temperature dependence of v Q was shown to be linear: v Q (T) = 147(1 - 0.033 T) MHz. As long as the value of v Q at room temperature was very close to that known for 111 Cd in the hcp lattice of Zn (133.5 MHz), we have checked if it could be assigned to the residual Zn metal in the sample. For the Zn sample melted and doped with 111 In at 8 GPa we have obtained v Q = 117.3 MHz at 300 K and 127 MHz at 80 K - both values considerably lower than that for 111 In-doped Zn samples prepared at an ambient pressure. For the sample re-melted after synthesis at high pressure in the low-pressure Ar atmosphere we have obtained v Q = 131(1) MHz. It can be noted that the value v Q (Zn) at 300 K is close to that obtained earlier in measurements with the sample at a pressure of ≅2 GPa It may be considered as an evidence of incomplete relaxation (at room temperature) of the Zn lattice after melting and quenching at 8 GPa. In the case of Zn sharp precession patterns with zero non-axiality parameter and very low damping were observed only with freshly prepared, or held at LN temperature samples, and after two days exposure at room temperature they suffered a considerable distortion. These data, and the fact that v Q (T) in Zn is known to follow the T 3/2 law, allow us to attribute the v Q value quoted above to 111 Cd nuclei at the substitutional sites with tetrahedral symmetry in the Zn sublattice of ZrZn 2

  15. Soya bean Gα proteins with distinct biochemical properties exhibit differential ability to complement Saccharomyces cerevisiae gpa1 mutant.

    Science.gov (United States)

    Roy Choudhury, Swarup; Wang, Yuqi; Pandey, Sona

    2014-07-01

    Signalling pathways mediated by heterotrimeric G-proteins are common to all eukaryotes. Plants have a limited number of each of the G-protein subunits, with the most elaborate G-protein network discovered so far in soya bean (Glycine max, also known as soybean) which has four Gα, four Gβ and ten Gγ proteins. Biochemical characterization of Gα proteins from plants suggests significant variation in their properties compared with the well-characterized non-plant proteins. Furthermore, the four soya bean Gα (GmGα) proteins exhibit distinct biochemical activities among themselves, but the extent to which such biochemical differences contribute to their in vivo function is also not known. We used the yeast gpa1 mutant which displays constitutive signalling and growth arrest in the pheromone-response pathway as an in vivo model to evaluate the effect of distinct biochemical activities of GmGα proteins. We showed that specific GmGα proteins can be activated during pheromone-dependent receptor-mediated signalling in yeast and they display different strengths towards complementation of yeast gpa1 phenotypes. We also identified amino acids that are responsible for differential complementation abilities of specific Gα proteins. These data establish that specific plant Gα proteins are functional in the receptor-mediated pheromone-response pathway in yeast and that the subtle biochemical differences in their activity are physiologically relevant.

  16. X-ray absorption spectroscopy of GeO2 glass to 64 GPa

    International Nuclear Information System (INIS)

    Hong, Xinguo; Newville, Matthew; Sutton, Stephen R; Rivers, Mark L; Duffy, Thomas S

    2014-01-01

    The structural behavior of GeO 2 glass has been investigated up to 64 GPa using results from x-ray absorption spectroscopy in a diamond anvil cell combined with previously reported density measurements. The difference between the nearest Ge–O distances of glassy and rutile-type GeO 2 disappears at the Ge–O distance maximum at 20 GPa, indicating completion of the tetrahedral–octahedral transition in GeO 2 glass. The mean-square displacement σ 2 of the Ge–O distance in the first Ge–O shell increases progressively to a maximum at 10 GPa, followed by a substantial reduction at higher pressures. The octahedral glass is, as expected, less dense and has a higher compressibility than the corresponding crystalline phase, but the differences in Ge–O distance and density between the glass and the crystals are gradually eliminated over the 20–40 GPa pressure range. Above 40 GPa, GeO 2 forms a dense octahedral glass with a compressibility similar to that of the corresponding crystalline phase (α-PbO 2 type). The EXAFS and XANES spectra show evidence for subtle changes in the dense glass continuing to occur at these high pressures. The Ge–O bond distance shows little change between 45–64 GPa, and this may reflect a balance between bond shortening and a gradual coordination number increase with compression. The density of the glass is similar to that of the α–PbO 2 -type phase, but the Ge–O distance is longer and is close to that in the higher-coordination pyrite-type phase which is stable above ∼60 GPa. The density data provide evidence for a possible discontinuity and change in compressibility at 40–45 GPa, but there are no major changes in the corresponding EXAFS spectra. A pyrite-type local structural model for the glass can provide a reasonable fitting to the XAFS spectra at 64 GPa. (paper)

  17. Viscosity Measurements of Eclogite Melt up to 5.6 GPa and 2000 K

    Science.gov (United States)

    Liu, H.; Fei, Y.; Han, L.; Kono, Y.; Hou, M.; Zhao, Z.; Du, J.

    2014-12-01

    The melting and rheology of eclogite is critical for understanding the dynamics of the subduction zone and plate tectonic. Viscosity of eclogite melt as a function of depth is a key parameter to model the long-term chemical evolution of the subduction zone and volcanic magma. It also plays an important role in earthquakes and continent formation. However, the viscosity and rheology of eclogite melt remain poorly understood at high pressure and temperature. In this study, we have carried out in-situ falling-sphere viscometry measurements to determine the viscosity of eclogite melt from 1.3 to 5.6 GPa at temperatures between 1500 and 2000 K, using the Paris-Edinburgh cell at the 16-BM-B beamline of the High Pressure Collaborative Access Team (HPCAT) at the Advanced Photon Source. We used a natural eclogite sample with 47.7wt% SiO2. The viscosity (η) was calculated with the Stokes' equation. The viscosity of eclogite melt decreases between 1.3 and 5.6 GPa at 2000K. At 1.4 GPa and 2000K the viscosity is 0.43 Pa·s, whereas at 5.6 GPa and 2000 K it is 0.13Pa·s. No minimum in the viscosity of eclogite was found in the measured pressure range up to 5.6 GPa.

  18. The influence of MCAT and GPA preadmission academic metrics on interview scores.

    Science.gov (United States)

    Gay, Steven E; Santen, Sally A; Mangrulkar, Rajesh S; Sisson, Thomas H; Ross, Paula T; Zaidi, Nikki L Bibler

    2018-03-01

    Medical school admissions interviews are used to assess applicants' nonacademic characteristics as advocated by the Association of American Medical Colleges' Advancing Holistic Review Initiative. The objective of this study is to determine whether academic metrics continue to significantly influence interviewers' scores in holistic processes by blinding interviewers to applicants' undergraduate grade point averages (uGPA) and Medical College Admission Test (MCAT). This study examines academic and demographic predictors of interview scores for two applicant cohorts at the University of Michigan Medical School. In 2012, interviewers were provided applicants' uGPA and MCAT scores; in 2013, these academic metrics were withheld from interviewers' files. Hierarchical regression analysis was conducted to examine the influence of academic and demographic variables on overall cohort interview scores. When interviewers were provided uGPA and MCAT scores, academic metrics explained more variation in interview scores (7.9%) than when interviewers were blinded to these metrics (4.1%). Further analysis showed a statistically significant interaction between cohort and uGPA, indicating that the association between uGPA and interview scores was significantly stronger for the 2012 unblinded cohort compared to the 2013 blinded cohort (β = .573, P metrics from interviewers' files may promote assessment of nonacademic characteristics independently from academic metrics.

  19. Raman measurements of phase transitions in dense solid hydrogen and deuterium to 325 GPa.

    Science.gov (United States)

    Zha, Chang-sheng; Cohen, R E; Mao, Ho-kwang; Hemley, Russell J

    2014-04-01

    Raman spectroscopy of dense hydrogen and deuterium performed to 325 GPa at 300 K reveals previously unidentified transitions. Detailed analysis of the spectra from multiple experimental runs, together with comparison with previous infrared and Raman measurements, provides information on structural modifications of hydrogen as a function of density through the I-III-IV transition sequence, beginning near 200 GPa at 300 K. The data suggest that the transition sequence at these temperatures proceeds by formation of disordered stacking of molecular and distorted layers. Weaker spectral changes are observed at 250, 285, and 300 GPa, that are characterized by discontinuities in pressure shifts of Raman frequencies, and changes in intensities and linewidths. The results indicate changes in structure and bonding, molecular orientational order, and electronic structure of dense hydrogen at these conditions. The data suggest the existence of new phases, either variations of phase IV, or altogether new structures.

  20. Raman and IR Spectroscopy Studies on Propane at Pressures of Up to 40 GPa.

    Science.gov (United States)

    Kudryavtsev, Daniil; Serovaiskii, Alexander; Mukhina, Elena; Kolesnikov, Anton; Gasharova, Biliana; Kutcherov, Vladimir; Dubrovinsky, Leonid

    2017-08-17

    Raman and IR spectroscopy studies on propane were performed at pressures of up to 40 GPa at ambient temperatures using the diamond anvil cell technique. Propane undergoes three phase transitions at 6.4(5), 14.5(5), and 26.5(5) GPa in Raman spectroscopy and at 7.0(5), 14.0(5), and 27.0(5) GPa in IR spectroscopy. The phase transitions were identified using the Raman and IR splitting modes and the appearance or disappearance of peaks, which clearly corresponded to the changes in the frequencies of the modes as the pressure changed. Our results demonstrate the complex high-pressure behavior of solid propane.

  1. Gas metal arc weldability of 1.5 GPa grade martensitic steels

    Science.gov (United States)

    Hwang, Insung; Yun, Hyeonsang; Kim, Dongcheol; Kang, Munjin; Kim, Young-Min

    2018-01-01

    The gas metal arc weldability of 1.5 GPa grade martensitic (MART) steel was evaluated using both inverter direct current (DC) and DC pulse power type welders, under conditions of different welding currents, welding speeds, and shielding gasses. By investigating the bead appearance, tensile strength, and arc stability, it was determined that DC pulse power is better than inverter DC power for arc welding of 1.3 mm thick 1.5 GPa grade MART steel. Further, from the results of the weldability for various shielding gases, it was determined that mixed shielding gas is more effective for welding 1.5 GPa grade MART steel than is pure inert gas (Ar) or active (CO2) gas. In the case of pure shielding gas, no sound bead was formed under any conditions. However, when the mixed shielding gas was used, sound and fine beads were obtained.

  2. Dense Carbon Monoxide to 160 GPa: Stepwise Polymerization to Two-Dimensional Layered Solid

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Young-Jay; Kim, Minseob; Lim, Jinhyuk; Dias, Ranga; Klug, Dennis; Yoo, Choong-Shik

    2016-11-14

    Carbon monoxide (CO) is the first molecular system found to transform into a nonmolecular “polymeric” solid above 5.5 GPa, yet been studied beyond 10 GPa. Here, we show a series of pressure-induced phase transformations in CO to 160 GPa: from a molecular solid to a highly colored, low-density polymeric phase I to translucent, high-density phase II to transparent, layered phase III. The properties of these phases are consistent with those expected from recently predicted 1D P21/m, 3D I212121, and 2D Cmcm structures, respectively. Thus, the present results advocate a stepwise polymerization of CO triple bonds to ultimately a 2D singly bonded layer structure with an enhanced ionic character.

  3. An ab initio study of WO sub 3 under pressure up to 30 GPa

    CERN Document Server

    Pagnier, T

    2003-01-01

    High-pressure polymorphs of WO sub 3 have been studied with a first-principles pseudopotential method. The medium-range (0.01-20 GPa) and high-range (20-30 GPa) polymorphs have been characterized and are compared with recent experimental results. The main new feature is the appearance of a sevenfold coordinated tungsten in the high-pressure polymorph. The subtle phase transitions that were induced from Raman spectra evolutions have not been confirmed. However, changes in the W-O distances and O-W-O and W-O-W angles may explain the changes in Raman spectra.

  4. Solid-state phase transitions in CuCl under hydrostatic pressures to 12.8 GPa

    International Nuclear Information System (INIS)

    Liebenberg, D.H.; Mills, R.L.; Huang, C.Y.; Olsen, C.; Schmidt, L.C.

    1981-01-01

    The phase transitions in solid CuCl under hydrostatic conditions at pressures to 12.8 GPa are examined. The transition at 4.4 GPa from zinc-blende to tetragonal is observed. Our negative observations for the upper transition at 8.2 GPa and for the formation of an opaque phase due to the disproportionation reaction support the contention that pressure gradients are important in affecting the behavior of pure CuCl

  5. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

    Energy Technology Data Exchange (ETDEWEB)

    Gallington, Leighanne C.; Hester, Brett R.; Kaplan, Benjamin S. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332‐0400 (United States); Wilkinson, Angus P., E-mail: angus.wilkinson@chemistry.gatech.edu [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332‐0400 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332‐0245 (United States)

    2017-05-15

    Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP{sub 2}O{sub 7} family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} exhibited a very strong dependence on pressure (∼700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV{sub 2}O{sub 7} was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively). - Graphical abstract: The temperature at which ZrV{sub 2}O{sub 7} transforms to a phase displaying negative thermal expansion is strongly pressure dependent. The high temperature form of ZrV{sub 2}O{sub 7} is elastically stiffer than the low temperature form. - Highlights: • The order-disorder phase transition temperatures in ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} are strongly pressure dependent (∼700 K.GPa). • The high temperature (disordered) phase of ZrV{sub 2}O{sub 7} is much stiffer than the ambient temperature (ordered) phase. • Compression reduces the magnitude of the negative thermal expansion in the high temperature phase of ZrV{sub 2}O{sub 7}.

  6. Hyperosmotic stress strongly potentiates serum response factor (SRF)-dependent transcriptional activity in ehrlich lettré ascites cells through a mechanism involving p38 mitogen-activated protein kinase

    DEFF Research Database (Denmark)

    Gorbatenko, Andrej; Wiwel, Maria; Klingberg, Henrik

    2011-01-01

    ) and cAMP response element-binding protein (CREB) are differentially regulated in ELA cells. SRF Ser103 phosphorylation and SRF-dependent transcriptional activity were strongly augmented 5–30¿min and 24¿h, respectively, after hyperosmotic stress (50% increase in extracellular ionic strength), in a p38...... is transiently inhibited while p38 MAPK is activated, in turn impacting on cell survival (Pedersen et al., 2007, Cell Physiol Biochem 20: 735–750). Here, we show that downstream of these kinases, two transcription factors with major roles in control of cell proliferation and death, serum response factor (SRF......Long-term osmotic stress results in altered gene transcription, however, with the exception of the TonE/TonEBP system, the underlying mechanisms are poorly understood. We previously showed that upon osmotic shrinkage of Ehrlich Lettré Ascites (ELA) fibroblasts, the MEK1-ERK1/2 pathway...

  7. 40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.

    Science.gov (United States)

    2010-07-01

    ...) Designation. Any refiner or importer shall designate any gasoline produced or imported that is subject to the... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase...

  8. Dual Credit Enrollment and GPA by Ethnicity and Gender at Texas 2-Year Colleges

    Science.gov (United States)

    Young, Robert D., Jr.

    2013-01-01

    Purpose: The purpose of this investigation was to determine the extent to which differences were present in dual credit course enrollment. Specifically examined were whether differences were present in the first semester GPA and at the end of the first two semesters for students who enrolled in dual credit courses while in high school from…

  9. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  10. Standardized Testing Placement and High School GPA as Predictors of Success in Remedial Math

    Science.gov (United States)

    Burrow, Susan C.

    2013-01-01

    The purpose of this quantitative study was to determine if a relationship existed between success in elementary algebra and a set of predictor variables including COMPASS score and high school GPA. Relationships for intermediate algebra and college credit accumulation over three semesters were also examined with COMPASS score and high school GPA…

  11. AC calorimetry of H2O at pressures up to 9 GPa in diamond anvil cells

    Science.gov (United States)

    Geballe, Zachary M.; Struzhkin, Viktor V.

    2017-06-01

    If successfully developed, calorimetry at tens of GPa of pressure could help characterize phase transitions in materials such as high-pressure minerals, metals, and molecular solids. Here, we extend alternating-current calorimetry to 9 GPa and 300 K in a diamond anvil cell and use it to study phase transitions in H2O. In particular, water is loaded into the sample chambers of diamond-cells, along with thin metal heaters (1 μm-thick platinum or 20 nm-thick gold on a glass substrate) that drive high-frequency temperature oscillations (20 Hz to 600 kHz; 1 to 10 K). The heaters also act as thermometers via the third-harmonic technique, yielding calorimetric data on (1) heat conduction to the diamonds and (2) heat transport into substrate and sample. Using this method during temperature cycles from 300 to 200 K, we document melting, freezing, and proton ordering and disordering transitions of H2O at 0 to 9 GPa, and characterize changes in thermal conductivity and heat capacity across these transitions. The technique and analysis pave the way for calorimetry experiments on any non-metal at pressures up to ˜100 GPa, provided a thin layer (several μm-thick) of thermal insulation supports a metallic thin-film (tens of nm thick) Joule-heater attached to low contact resistance leads inside the sample chamber of a diamond-cell.

  12. Compression of glycolide-h4 to 6GPa

    DEFF Research Database (Denmark)

    Hutchison, Ian B.; Bull, Craig L.; Marshall, William G.

    2017-01-01

    This study details the structural characterization of glycolide-h4 as a function of pressure to 6GPa using neutron powder diffraction on the PEARL instrument at ISIS Neutron and Muon source. Glycolide-h4, rather than its deuterated isotopologue, was used in this study due to the difficulty of deu...

  13. Compressibility and Optical Properties of Single Crystal Magnesite and Siderite up to 75 GPa

    Science.gov (United States)

    Lavina, B.; Dera, P.; Downs, R. T.; Prakapenka, V.

    2008-12-01

    The stability and properties of carbonates at mantle conditions are of great importance for the carbon cycle, controlling the fate of subducting carbonate rich crust and mantle fertilization processes. Theoretical and experimental observations indicate that magnesite is the product of reaction of carbonates with silicate minerals, and it has been found to be stable within lower mantle conditions. A siderite component is likely to be present at mantle conditions in equilibrium with the surrounding iron bearing phases. We conducted compression experiments on natural single crystals of magnesite and Mg-siderite. By using neon as pressure transmitting medium we collected diffraction data in nearly hydrostatic conditions up to ~ 75GPa. The compression curve of magnesite is in good agreement with literature data. Siderite shows a steep volume decrease between 40 and 50 GPa which is most likely related to the change of ionic size associated with the spin pairing reported in siderite at ~ 50GPa. Siderites single crystals, about 10μ thick, were initially colorless and assumed a green color, progressively deeper, after ~ 40GPa and turned into red at the highest pressure. The color variations were reversible, quantitative absorption data are going to be presented. Siderite is not a major phase of the earth's mantle, therefore its density and optical properties are not likely to significantly affect the earth's density profile or the thermal equilibrium, however it might help to learn in detail the effect of spin transition on mineral physical properties.

  14. High Pressure Study of Electrical Resistivity of CeB6 to 136 GPa

    Science.gov (United States)

    Forouzani, Neda; Lim, Jinhyuk; Schilling, James; Fabbris, Gilberto; Fisk, Zachary

    2014-03-01

    Since the 1960's the dense Kondo compound cerium hexaboride (CeB6) has attracted a great deal of interest. To investigate whether this material might evolve into a topological insulator under sufficient pressure, we have carried out four-point electrical resistivity measurements on CeB6 over the temperature range 1.3 K to 295 K in a diamond anvil cell to 136 GPa. Although a transition into an insulating phase is not observed, the evolution of the initial dense Kondo state under such extreme pressures is of considerable interest. As reported in earlier studies to 13 GPa, the temperature of the resistivity maximum near 3 K initially increases with pressure. We observe that between 33 and 53 GPa the resistivity maximum disappears and by 83 GPa CeB6 appears to have settled into a Fermi liquid state. The marked changes observed under pressure suggest that a change in valence and/or a structural transition may have occurred. Synchrotron x-ray diffraction measurements are being carried out to investigate possible changes in crystal structure under extreme pressures. Work at Washington Univ. supported by NSF DMR-1104742 and Carnegie/DOE/NNSA DE-FC52-08NA28554.

  15. Unraveling the identity of FoxP3+ regulatory T-cells in GPA-patients

    NARCIS (Netherlands)

    Abdulahad, W.H.; Stegeman, Coen A.; Huitema, M.G.; Limburg, Pieter C.; Rutgers, Abraham; Heeringa, Peter; Kallenberg, Cees G.M.

    2013-01-01

    Background/Purpose: Human FoxP3+ Th-cells are heterogeneous in function and include not only suppressive cells (TRegs) but also nonsuppressive cells that abundantly secrete proinflammatory cytokines. We have previously shown that FoxP3+ Th-cells were increased in GPA-patients during remission as

  16. Grade Point Average: Report of the GPA Pilot Project 2013-14

    Science.gov (United States)

    Higher Education Academy, 2015

    2015-01-01

    This report is published as the result of a range of investigations and debates involving many universities and colleges and a series of meetings, presentations, discussions and consultations. Interest in a grade point average (GPA) system was originally initiated by a group of interested universities, progressing to the systematic investigation…

  17. Short- and Long-Term Validity of High School GPA for Admission to Colleges outside the United States

    Science.gov (United States)

    Al-Hattami, Abdulghani

    2014-01-01

    High school GPA is the only admission criterion that is currently used by many colleges in Yemen to select their potential students. Its predictive validity was investigated to ensure the accuracy of the admission decisions in these colleges. The relationship between students' persistence in the 4 years of college and high school GPA was studied…

  18. Increased frequency of circulating IL-21 producing Th-cells in patients with granulomatosis with polyangiitis (GPA)

    NARCIS (Netherlands)

    Abdulahad, Wayel H; Lepse, Nikola; Stegeman, Coen A; Huitema, Minke G; Doornbos-van der Meer, Berber; Tadema, Henko; Rutgers, Abraham; Limburg, Pieter C; Kallenberg, Cees G M; Heeringa, Peter

    2013-01-01

    INTRODUCTION: The present study aimed to explore a possible role for IL-21 producing Th-cells in the immunopathogenesis of granulomatosis with polyangiitis (GPA). METHODS: Peripheral blood from 42 GPA patients in remission and 29 age-matched healthy controls (HCs) were stimulated in vitro, and the

  19. Accuracy of Self-Reported College GPA: Gender-Moderated Differences by Achievement Level and Academic Self-Efficacy

    Science.gov (United States)

    Caskie, Grace I. L.; Sutton, MaryAnn C.; Eckhardt, Amanda G.

    2014-01-01

    Assessments of college academic achievement tend to rely on self-reported GPA values, yet evidence is limited regarding the accuracy of those values. With a sample of 194 undergraduate college students, the present study examined whether accuracy of self-reported GPA differed based on level of academic performance or level of academic…

  20. The compression behavior of blödite at low and high temperature up to ~10GPa: Implications for the stability of hydrous sulfates on icy planetary bodies

    Energy Technology Data Exchange (ETDEWEB)

    Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra; Fei, Yingwei; Prakapenka, Vitali

    2017-03-01

    Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ~10.4 GPa and temperatures from ~118.8 K to ~490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperature equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede. The experimentally determined volume expansivity, α, varies from 7.6 (7) 10-5 K-1 at 0.0001 GPa (from 118.8 to 413.15 K) to 2.6 (3) 10-5 K-1 at 10 GPa (from 313.0 to 453.0 K) with a δα/δP coefficient = -5.6(9)10-6 GPa-1 K-1. The bulk modulus calculated from the least squares fitting of P-V data on the isotherm at 413 K using a second-order Birch - Murnaghan equation of state is 38(5) GPa, which gives the value of δK/δT equal to 0.01(5) GPa K-1. The thermo-baric behavior of blödite appears strongly anisotropic with c lattice parameter being more deformed with respect to a and b. Thermogravimetric analyses performed at ambient pressure showed three endotherms at 413 K, 533 K and 973 K with weight losses of approximately 11%, 11% and 43% caused by partial dehydration, full dehydration and sulfate decomposition respectively. Interestingly, no clear evidence of dehydration was observed up to ~453 K and ~10.4 GPa, suggesting that pressure acts to stabilize the crystalline structure of blödite. The data collected allow to write the following equation of state, V(P, T) = V

  1. Structural stability of boron carbide under pressure proven by spectroscopic studies up to 73 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Chuvashova, Irina [Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth (Germany); Bayerisches Geoinstitut, University of Bayreuth (Germany); Gasharova, Biliana; Mathis, Yves-Laurent [IBPT, Karlsruhe Institute of Technology, Karlsruhe (Germany); Dubrovinsky, Leonid [Bayerisches Geoinstitut, University of Bayreuth (Germany); Dubrovinskaia, Natalia [Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth (Germany)

    2017-11-17

    Being a material of choice for lightweight armor applications, boron carbide has been intensively studied. Its behavior under pressure was investigated using both theoretical and experimental methods, such as powder X-ray diffraction and vibrational spectroscopy. As there is a discrepancy in experimental observations, in the presented work we studied vibrational properties of commercially available, ''nearly stoichiometric'' B{sub 4}C using IR and Raman spectroscopy up to 73 GPa. No phase transitions were found in the entire pressure range. Our results are at odds with the recent report of a phase transition in B{sub 4.3}C at about 40 GPa. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Angle-dispersive neutron diffraction under high pressure to 10 GPa

    International Nuclear Information System (INIS)

    Klotz, S.; Straessle, Th.; Rousse, G.; Hamel, G.; Pomjakushin, V.

    2005-01-01

    We present a method which allows high-quality powder neutron diffraction patterns to be obtained under pressure by angle-dispersive diffraction to at least 10 GPa. This technique uses a new type of Paris-Edinburgh press in conjunction with sintered boron nitride anvils. As an example, we show NiO diffraction patterns obtained under purely hydrostatic pressures up to 10 GPa. These data were collected within a few hours, and are free from any contaminating signal from the pressure cell. High-resolution nuclear and magnetic structural information can be readily extracted by Rietveld refinements, without additional data correction. This technique will allow powder neutron diffraction at elevated pressures to become a standard tool on continuous neutron facilities

  3. Structure of boron carbide after applying shear deformations under a pressure to 55 GPa

    Science.gov (United States)

    Annenkov, M. R.; Kulnitskiy, B. A.; Perezhogin, I. A.; Ovsyannikov, D. A.; Popov, M. Yu.; Blank, V. D.

    2017-05-01

    Transmission electron microscopy has been used to study the structural features of boron carbide treated in a high-pressure shear chamber with diamond anvils in the pressure range 25-55 GPa. Such a treatment has been shown to lead to the predominant crack formation along planes {10 11 } and {10 12} and also the formation of polytypes in the {10 11} planes and strain bands in the {10 12} planes.

  4. GPA/GPSA/OSU-Okmulgee natural gas compression technician training program

    Energy Technology Data Exchange (ETDEWEB)

    Doede, S.

    1999-07-01

    Approximately one year ago, OSU-Okmulgee and the Gas Processors Association began discussions about the possibility of developing a natural Gas Technician Training Program for GPA members. Following a presentation to the Membership and Services Committee, Chairman John Ehlers solicited and obtained the approval of the GPA Executive Committee to sponsor the program. Participation in the program was also made available to GPSA members. The purpose of the program is to upgrade the technical competency and professional level of incoming natural gas compression technicians. It educates students to analytically diagnose, service and maintain gas compression equipment and systems using industry recommended procedures, special tools and service information. It also provides course content, which will enable successful graduates to advance in position after additional experience, and to understand new systems, technologies and components as they are introduced. The two-year Associate-In-Applied Science Degree program includes six successive college semesters. Nearly one-half of the time is designated for technical/academic education at Oklahoma State University-Okmulgee with the balance of time allocated for on-the-job internship experiences at sponsoring GPA/GPSA members. Each block of technical education and general education course work is followed by an immediate work experience time period designated to reinforce the technical and general education. These time periods are approximately seven and one-half weeks in length each. It is essential for the success of the students and the program that the students' education at OSU-Okmulgee and work experiences at GPA/GPSA member facilities be closely aligned for maximum student learning and retention. In addition to technical classes on gas compression equipment and components, the courses offered in math, speech, technical writing, psychology and ethics for example, prepare students to be able to communicate well, get

  5. A Correlation Study on Attachment Style and GPA of Students at an Alternative Education Center

    OpenAIRE

    Cindy L. Burdick

    2014-01-01

    Adolescents in America are dropping out of school in alarming rates. In the school year 2009- 2010, 514,238 adolescents dropped out of high school. While alternative education centers have been created to meet the needs of these individuals, they are not always successful as evidenced by a graduation rate below 5% in several alternative centers in Florida. Previous studies have shown that students with a positive attachment style have higher grade point averages (GPA) and perform better in sc...

  6. Single-crystal elasticity of diaspore, AlOOH, to 12 GPa by Brillouin scattering

    Science.gov (United States)

    Jiang, Fuming; Majzlan, Juraj; Speziale, Sergio; He, Duanwei; Duffy, Thomas S.

    2008-11-01

    The high-pressure elasticity of diaspore (AlOOH) has been determined by Brillouin spectroscopy to 12 GPa in diamond anvil cells. Experiments were carried out using a 16:3:1 methanol-ethanol-water mixture as pressure medium, and ruby as pressure standard. Acoustic velocities were measured in three roughly orthogonal planes at ambient and eight elevated pressures. The nine individual elastic stiffness constants of the orthorhombic crystal were obtained by fitting the velocity data to Christoffel's equation. Aggregate elastic moduli and pressure derivatives were calculated from the Cijs by fits to Eulerian finite strain equations, yielding: K=152(1) GPa, G0 = 117.2(5) GPa, (/∂P)T=3.7(1),   (=1.5(1) for the Voigt-Reuss-Hill average. All individual Cijs increase with pressure but C23 and C55 exhibit anomalously low pressure derivatives. From calculated linear compressibilities, the a-axis is the most compressible. The b-axis becomes the least compressible axis at high pressures. Over the examined pressure range, the azimuthal P-wave anisotropy decreased from 22% to 16%, while the azimuthal S-wave anisotropy increased from 15% to 21%. Both volume and axial compression curves calculated using our Brillouin results are in good agreement with the results from static compression studies. High-pressure sound velocities in diaspore exceed those of other hydrous minerals as well as many anhydrous phases relevant to Earth's upper mantle.

  7. Compaction of Ceramic Microspheres, Spherical Molybdenum Powder and Other Materials to 3 GPa

    International Nuclear Information System (INIS)

    Carlson, S R; Bonner, B P; Ryerson, F J; Hart, M M

    2006-01-01

    Pressure-volume relationships were measured at room temperature for eight granular materials and one specimen of epoxy foam. The granular materials included hollow ceramic microspheres, spherical molybdenum powder, Ottawa sand, aluminum, copper, titanium and silicon carbide powders and glassy carbon spheres. Measurements were made to 0.9 GPa in a liquid medium press for all of the granular materials and to 3 GPa in a solid medium press for the ceramic microspheres and molybdenum powder. A single specimen of epoxy foam was compressed to 30 MPa in the liquid medium press. Bulk moduli were calculated as a function of pressure for the ceramic microspheres, the molybdenum powder and three other granular materials. The energy expended in compacting the granular materials was determined by numerically integrating pressure-volume curves. More energy was expended per unit volume in compacting the molybdenum powder to 1 GPa than for the other materials, but compaction of the ceramic microspheres required more energy per gram due to their very low initial density. The merge pressure, the pressure at which all porosity is removed, was estimated for each material by plotting porosity against pressure on a semi-log plot. The pressure-volume curves were then extrapolated to the predicted merge pressures and numerically integrated to estimate the energy required to reach full density for each material. The results suggest that the glassy carbon spheres and the ceramic microspheres would require more energy than the other materials to attain full density

  8. Phase behaviour and thermoelastic properties of ammonia hydrate and ice polymorphs from 0 - 2 GPa

    Science.gov (United States)

    Fortes, A. D.; Wood, I. G.; Vocadlo, L.

    2008-12-01

    Ammonia remains amongst the most plausible planetary "antifreeze" agents, and its physical properties in hydrate compounds under the appropriate conditions (roughly 0 - 5 GPa, 100 - 300 K) must be known in order for it to be accommodated in planetary models. The pressure melting curve, and the expected polymorphism of the stoichiometric ammonia hydrates have implications for the internal structure of large icy moons like Titan, leading to phase layering and the possible persistence of deep subsurface oceans, the latter being sites of high astrobiological potential. Aqueous ammonia is also a candidate substance involved in cryomagmatism on Titan, and again the melting behaviour, and densities of liquids and solids, in the ammonia-water system must be known to model properly the partial melting and propagation of magma. We describe the results of a series of powder neutron diffraction experiments over the range 0 - 2.0 GPa, 150 - 280 K which were carried out with the objective of determining the phase behaviour and thermoelastic properties of ammonia dihydrate. In addition to the low-pressure cubic crystalline phase, ADH I, we have identified two closely related monoclinic polymorphs of ammonia dihydrate (ADH IIa and IIb) in the range 0.45 - 0.60 GPa (at 175 K), and have determined that this phase dissociates to a mixture of ammonia monohydrate phase II and ice II when warmed to ~190 K, which in turn melts at a binary eutectic at ~196 K; AMH II has a large (Z = 16) orthorhombic unit cell. Above 0.60 GPa, an orthorhombic polymorph of ammonia dihydrate, which we have referred to previously as ADH IV, persists to pressures > 3 GPa, and appears to be the liquidus phase over this whole pressure range. We have observed this phase co- existing with both ice II and ice VI. Here we describe the most plausible synthesis of the high-pressure phase diagram which explains our observations, and provide measurements of the densities, thermal expansion, bulk moduli, and crystal

  9. The Thurgood Marshall School of Law Empirical Findings: A Report of the 2012 Friday Academy Attendance and Statistical Comparisons of 1L GPA (Predicted and Actual)

    Science.gov (United States)

    Kadhi, T.; Rudley, D.; Holley, D.; Krishna, K.; Ogolla, C.; Rene, E.; Green, T.

    2010-01-01

    The following report of descriptive statistics addresses the attendance of the 2012 class and the average Actual and Predicted 1L Grade Point Averages (GPAs). Correlational and Inferential statistics are also run on the variables of Attendance (Y/N), Attendance Number of Times, Actual GPA, and Predictive GPA (Predictive GPA is defined as the Index…

  10. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  11. High-pressure x-ray diffraction study of LiIO sub 3 to 75 GPa

    CERN Document Server

    Zhang, W W; Pan Yue Wu; Dong, S S; Liu, J; Zou Guang Tian

    2002-01-01

    In situ high-pressure energy-dispersive x-ray diffraction measurements on alpha-LiIO sub 3 have been performed by using a diamond anvil cell device with synchrotron radiation up to 75 GPa at room temperature. No new phase was found. The second Birch-Murnaghan equation of state is fitted with B sub 0 = 55 +- 3 GPa for the zero-pressure bulk modulus, B sub 0 ' = 2.9 +- 0.4 for its pressure derivative.

  12. Adakite Induced Metasomatism of the Mantle Wedge: a Systematic Experimental Study at 1.6 GPa

    Science.gov (United States)

    Rapp, R. P.; Laporte, D.; Martin, H.

    2005-12-01

    In order to better understand the origin and nature of the slab-derived agent in subduction zones, and how the arc geochemical signature is imparted to the mantle wedge, it is necessary to have specific geochemical parameters to differentiate between fluids and partial melts generated by dehydration of the crustal component (MORB) of the downgoing oceanic lithosphere. ``Adakite'' magmatism in subduction zones is generally attributed to partial melting of basaltic oceanic crust during prograde metamorphism and dehydration of the subducting slab. In this study, we focus on adakites or ``slab melts'' as the agent of metasomatism of the overlying mantle wedge, armed beforehand with relatively comprehensive major- and trace-element constraints on the geochemical nature of these melts from our previous work. We have conducted a series of melt-rock reaction experiments in the piston-cylinder apparatus at 1.6 GPa and temperatures of 1000-1250°C in which we systematically vary the proportion of adakite melt relative to mantle peridotite. Our starting materials consist of mechanical mixtures of an adakite glass containing ~8 wt% H2O (pre-hydrated in an internally-heated pressure vessel at 900°C and 2.5 kbar for 3-4 hours), and a natural depleted peridotite powder made from a xenolith from the Kamchatkan sub-arc mantle. Experiments were conducted in thick-walled, pressure-welded gold capsules at temperatures below 1100°C, and in Ag-Pd capsules at higher temeperatures; the adakite melt:peridotite rock ratio has been varied from 2:1 to 1:4, with the mixtures allowed to equilibrate over the course of 5-10 days, depending on run temperature. Our results indicate that the reaction between adakite melt and peridotite is dominated by the consumption of olivine and crystallization of orthopyroxene and amphibole, and takes the general form: melts1 (pristine adakite) + olivine 0 melt2 (hybridized adakite) + orthopyroxene + amphibole. The chemical characteristics of metasomatic

  13. Volume temperature relationship for iron at 330 GPa and the Earth's core density deficit

    Science.gov (United States)

    Shanker, J.; Singh, B. P.; Srivastava, S. K.

    2004-12-01

    Estimates of core density deficit (cdd) of the Earth's outer core recently reported by Anderson and Isaak [Another look at the core density deficit of Earth's outer core, Phys. Earth Planet Int. 131 (2002) 19-27] are questionable in view of the serious errors in the pressure-volume and bulk modulus data due to an inadequacy in the calibration process used by Mao et al. [Static compression of iron to 300 GPa and Fe0.8Ni0.2 alloy to 200 GPa: implications for the core, J. Geophys. Res. 94 (1990) 21737-21742]. The data used by Anderson and Isaak deviate significantly from the corresponding values derived from seismology. In the present study we have used the input data on density, isothermal bulk modulus and its pressure derivative from Stacey and Davis [High pressure equations of state with application to lower mantle and core, Phys. Earth Planet Int. 142 (2004) 137-184] which are consistent with the seismological data. Volumes of hexagonal close-packed iron have been calculated at different temperatures under isobaric conditions at P = 330 GPa, the inner core boundary (ICB) pressure using the relationship between thermal pressure and volume expansion based on the lattice potential theory originally due to Born and Huang [Dynamical Theory of Crystal Lattices, Oxford University Press, Oxford, 1954, p. 50]. The formulation for thermal pressure used by Anderson and Isaak has been modified by taking into account the variations of thermal expansivity α and isothermal bulk modulus KT with temperature. Values of cdd are then estimated corresponding to different temperatures ranging from 4000 to 8000 K. The results for cdd at different temperatures obtained in the present study are significantly higher than those estimated by Anderson and Isaak suggesting that the cdd for the Earth's outer core is nearly 10%. The effects of nickel when an Fe-Ni alloy replaces Fe are estimated and found to be insignificant.

  14. Phase E in a water-saturated peridotite system at 9.3 GPa

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Leinenweber, Kurt; Hervig, Richard L.

    1994-01-01

    The stability of hydrous phases in a natural upper mantle system has been investigated at 9.3 GPa using a gel of KLB-1 peridotite composition with brucite which contains 14 wt. percent (30 atom. percent) water. No hydrous mineral was found at 950 (+150 -50) degree C. At 800 degree C, an assemblage of phase A, phase E, enstatite, clinohumite, and garnet is obtained. Although there is a significant thermal gradient over the sample, phase E is found to be surrounded by phase A in the lower temperature part. Electron probe analyses show that phase E has 35.5 SiO2, 4.4 Al2O3, 41.1 MgO and 8.5 wt. percent FeO* (Mg value is 90) with an oxide sum of 89.7 wt. percent, and possesses a stoichiometry similar to that proposed by Kanzaki. CaO and TiO2 are both less than 0.1 wt. percent. Coexisting phase A has 0.5 wt. percent CaO but only 0.4 wt. percent Al2O3 concentration. Phase A coexists with only enstatite in the water-saturated MgO-FeO-SiO2 system at 800 degree C and 9.3 GPa as well as the results in the water-saturated MgO-SiO2 system. Therefore it is suggested that the addition of Al2O3 expands the stability field of phase E to lower than 13 - 17 GPa in the water-saturated MgO-SiO2 system.

  15. The pressure-induced structural response of rare earth hafnate and stannate pyrochlore from 0.1-50 GPa

    Science.gov (United States)

    Turner, K. M.; Rittman, D.; Heymach, R.; Turner, M.; Tracy, C.; Mao, W. L.; Ewing, R. C.

    2017-12-01

    Complex oxides with the pyrochlore (A2B2O7) and defect-fluorite ((A,B)4O7) structure-types undergo structural transformations under high-pressure. These compounds are under consideration for applications including as a proposed waste-form for actinides generated in the nuclear fuel cycle. High-pressure transformations in rare earth hafnates (A2Hf2O7, A=Sm, Eu, Gd, Dy, Y, Yb) and stannates (A2Sn2O7, A=Nd, Gd, Er) were investigated to 50 GPa by in situ Raman spectroscopy and synchrotron x-ray diffraction (XRD). Rare-earth hafnates form the pyrochlore structure for A=La-Tb and the defect-fluorite structure for A=Dy-Lu. Lanthanide stannates form the pyrochlore structure. Raman spectra revealed that at ambient pressure all compositions have pyrochlore-type short-range order. Stannate compositions show a larger degree of pyrochlore-type short-range ordering relative to hafnates. In situ high-pressure synchrotron XRD showed that rare earth hafnates and stannates underwent a pressure-induced phase transition to a cotunnite-like (Pnma) structure that begins between 18-25 GPa in hafnates and between 30-33 GPa in stannates. The phase transition is not complete at 50 GPa, and upon decompression, XRD indicates that all compositions transform to defect-fluorite with an amorphous component. In situ Raman spectroscopy showed that disordering in stannates and hafnates occurs gradually upon compression. Pyrochlore-structured hafnates retain short-range order to a higher pressure (30 GPa vs. <10 GPa) than defect-fluorite-structured hafnates. Hafnates and stannates decompressed from 50 GPa show Raman spectra consistent with weberite-type structures, also reported in irradiated stannates. The second-order Birch-Murnaghan equation of state fit gives a bulk modulus of 250 GPa for hafnate compositions with the pyrochlore structure, and 400 GPa for hafnate compositions with the defect-fluorite structure. Stannates have a lower bulk modulus relative to hafnates (between 80-150 GPa

  16. The heterodimeric glycoprotein hormone, GPA2/GPB5, regulates ion transport across the hindgut of the adult mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Jean-Paul Paluzzi

    Full Text Available A family of evolutionarily old hormones is the glycoprotein cysteine knot-forming heterodimers consisting of alpha- (GPA and beta-subunits (GPB, which assemble by noncovalent bonds. In mammals, a common glycoprotein hormone alpha-subunit (GPA1 pairs with unique beta-subunits that establish receptor specificity, forming thyroid stimulating hormone (GPA1/TSHβ and the gonadotropins luteinizing hormone (GPA1/LHβ, follicle stimulating hormone (GPA1/FSHβ, choriogonadotropin (GPA1/CGβ. A novel glycoprotein heterodimer was identified in vertebrates by genome analysis, called thyrostimulin, composed of two novel subunits, GPA2 and GPB5, and homologs occur in arthropods, nematodes and cnidarians, implying that this neurohormone system existed prior to the emergence of bilateral metazoans. In order to discern possible physiological roles of this hormonal signaling system in mosquitoes, we have isolated the glycoprotein hormone genes producing the alpha- and beta-subunits (AedaeGPA2 and AedaeGPB5 and assessed their temporal expression profiles in the yellow and dengue-fever vector, Aedes aegypti. We have also isolated a putative receptor for this novel mosquito hormone, AedaeLGR1, which contains features conserved with other glycoprotein leucine-rich repeating containing G protein-coupled receptors. AedaeLGR1 is expressed in tissues of the alimentary canal such as the midgut, Malpighian tubules and hindgut, suggesting that this novel mosquito glycoprotein hormone may regulate ionic and osmotic balance. Focusing on the hindgut in adult stage A. aegypti, where AedaeLGR1 was highly enriched, we utilized the Scanning Ion-selective Electrode Technique (SIET to determine if AedaeGPA2/GPB5 modulated cation transport across this epithelial tissue. Our results suggest that AedaeGPA2/GPB5 does indeed participate in ionic and osmotic balance, since it appears to inhibit natriuresis and promote kaliuresis. Taken together, our findings imply this hormone may play an

  17. Dynamic properties of Indiana, Fort Knox and Utah test range limestones and Danby Marble over the stress range 1 to 20 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, M.D.

    1994-12-01

    The responses of the following carbonate materials to shock loading and release have been measured: Indiana limestone (18% porosity; saturated and dry), Jeffersonville/Louisville Limestones (Fort Knox limestone) (variable dolomitization, low porosity), Danby Marble (essentially pure calcite; low porosity), and a limestone from the Utah Test and Training Range (low porosity, with 22% silica). Various experimental configurations were used, some optimized to yield detailed waveform information, others to yield a clean combination of Hugoniot states and release paths. All made use of velocity interferometry as a primary diagnostic. The stress range of 0 - 20 GPa was probed (in most cases, emphasizing the stress range 0 -10 GPa). The primary physical processes observed in this stress regime were material strength, porosity, and polymorphic phase transitions between the CaCO{sub 3} phases I, II, III and VI. Hydration was also a significant reaction under certain conditions. The Indiana Limestone studies in particular represent a significant addition to the low-pressure database for porous limestone. Temperature dependence and the effect of freezing were assessed for the Fort Knox limestone. Experimental parameters and detailed results are provided for the 42 impact tests in this series.

  18. Calibration of a belt apparatus to 1800°C and 6 GPa

    Science.gov (United States)

    Brey, G. P.; Weber, R.; Nickel, K. G.

    1990-09-01

    A belt type solid media high-pressure apparatus has been calibrated to the same accuracy as piston-cylinder apparatuses. This was achieved by ensuring high reproducibility of pressures and temperatures and by calibrating the system with well-established, internally consistent phase transitions. We have used the melting of silver (Mirwald and Kennedy, 1979), the quartz-coesite transition (Mirwald and Masonne, 1980), and the graphite-diamond boundary (Kennedy and Kennedy, 1976). High reproducibility of experimental conditions can be achieved by machining the various components of the furnace assembly very accurately and by using components which do not contaminate the thermocouple and have 99-100% theoretical density (in our case single-crystal MgO and natural polycrystalline CaF2). It is essential that the gasket material has well-defined mechanical properties: its friction behavior must be reproducible in each experiment so that the ram pressure always acts on the pressure vessel and the sample in the same way. Factory-processed pyrophyllite fulfills this requirement. With all precautions taken and on the basis of the reactions cited above, we claim an accuracy of ±7°C and ±(1% nominal pressure+0.05 GPa). This corresponds to the accuracy given by Mirwald et al. (1975) for a low-friction cell for a piston-cylinder apparatus. Our belt apparatus is used routinely to achieve pressures up to 6 GPa and temperatures up to 1800°C.

  19. Academic Self-Efficacy, Emotional Intelligence, GPA and Academic Procrastination in Higher Education

    Directory of Open Access Journals (Sweden)

    Meirav Hen

    2014-05-01

    Full Text Available Academic procrastination has been seen as an impediment to students' academic success because it decreases the quality and quantity of learning while increasing the severity of negative outcomes in students’ lives. Research findings suggest that academic procrastination is closely related to motivation variables such as self-efficacy and self-regulated learning, and with higher levels of anxiety, stress, and illness. Emotional Intelligence is the ability to assess, regulate, and utilize emotions. It has been found to be associated with academic self-efficacy and a variety of better outcomes, including academic performance. The purpose of the present study was to explore and provide an initial understanding to the relationships between emotional intelligence, academic procrastination and GPA, as mediated by academic selfefficacy. A convenience sampling of 287 college students was collected. Structural equation modeling analysis using AMOS was conducted to examine the mediation role of academic selfefficacy between emotional intelligence, procrastination and GPA. Findings indicated that Emotional intelligence has a negative indirect effect on academic procrastination and a positive indirect effect on academic performance. Further research is needed to explore the effect of emotional intelligence on academic procrastination and performance, and to further understand its implications for academic settings.

  20. NMR study of strongly correlated electron systems

    Science.gov (United States)

    Kitaoka, Y.; Tou, H.; Zheng, G.-q.; Ishida, K.; Asayama, K.; Kobayashi, T. C.; Kohda, A.; Takeshita, N.; Amaya, K.; Onuki, Y.; Geibel, G.; Schank, C.; Steglich, F.

    1995-02-01

    Various types of ground states in strongly correlated electron systems have been systematically investigated by means of NMR/NQR at low temperatures under high magnetic field and pressure. We focus on two well-known heavy-electron families, CeCu 2X 2 (X = Si and Ge) (Ce(122)) and UM 2Al 3 (M = Ni and Pd) (U(123)). The Cu NQR experiments on CeCu 2X 2 under high pressure indicate that the physical property of CeCu 2Ge 2 at high pressure, i.e. above the transition at 7.6 GPa from antiferromagnetic (AF) to superconductivity, are clearly related to tha CeCu 2Si 2 at ambient pressure. In addition to the H-T phase diagram established below 7 T, NMR and specific heat experiments on polycrystal CeCu 2.05Si 2 have revealed the presence of a new phase above 7 T. In a high-quality polycrystal of UPd 2Al 3 with a record high- Tc of 2 K at ambient pressure and the narrowest Al NQR line width, the nuclear-spin lattice relaxation rate, 27(1/ T1) measured in zero field has been found to obey the T3 law down to 0.13 K, giving strong evidence that the energy gap vanishes along lines on the Fermi surface. Thus it seems that all heavy-electron superconductors exhibit lines of zero gap, regardless of their different magnetic properties.

  1. High pressure in situ X-ray diffraction study of MnO to 137 GPa and comparison with shock compression experiment

    Science.gov (United States)

    Yagi, T.; Kondo, T.; Syono, Y.

    1998-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment, high pressure in situ X-ray observations were carried out up to 137 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil cell and X-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase was observed above about 40 GPa, which continues to increase up to 90 GPa. Two discontinuous changes of the diffraction profiles were observed at around 90 GPa and 120 GPa. The nature of the intermediate phase between 90 GPa and 120 GPa is not clear yet. It is neither cesium chloride (B2) nor nickel arsenide (B8) structure. On the other hand, the diffraction profile above 120 GPa can be reasonably well explained by the B8 structure. High pressure phases above 90 GPa have metallic luster and all the transformations are reversible on release of pressure.

  2. Optical absorbances of Gd3Ga5O12 single crystals under shock compression to 211 GPa

    Science.gov (United States)

    Liu, Q. C.; Zhou, X. M.; Luo, S. N.

    2017-04-01

    Shock-induced opacity in Gd3Ga5O12 (GGG) single crystals is investigated by transmission/emission measurements at 16 wavelengths (400-800 nm), as well as complementary particle velocity measurements at 1550 nm, in the pressure range of 47-211 GPa. Optical transmission spectra through the shocked samples are measured with a in-situ, shock-generated light source, and the resultant extinction coefficients of different wavelengths and shock pressures obtained. As shock strength increases, the optical opacity of the shocked GGG increases and peaks at 75 GPa (the transparent-opaque transition), drops at 75-100 GPa (the opaque-transparent transition), and then increases again. The transparency recovery coincides with a solid-solid phase transition. The microstructure changes associated with the solid-solid phase transition and plastic deformation most likely cause the loss and recovery of transparency. GGG can be useful as a high pressure window for laser velocimetry (1550 nm) or optical pyrometry (400-800 nm) in the ranges of 100-140 GPa and 80-120 GPa, respectively.

  3. Strength and deformation of shocked diamond single crystals: Orientation dependence

    Science.gov (United States)

    Lang, J. M.; Winey, J. M.; Gupta, Y. M.

    2018-03-01

    Understanding and quantifying the strength or elastic limit of diamond single crystals is of considerable scientific and technological importance, and has been a subject of long standing theoretical and experimental interest. To examine the effect of crystalline anisotropy on strength and deformation of shocked diamond single crystals, plate impact experiments were conducted to measure wave profiles at various elastic impact stresses up to ˜120 GPa along [110] and [111] crystal orientations. Using laser interferometry, particle velocity histories and shock velocities in the diamond samples were measured and were compared with similar measurements published previously for shock compression along the [100] direction. Wave profiles for all three orientations showed large elastic wave amplitudes followed by time-dependent inelastic deformation. From the measured wave profiles, the elastic limits were determined under well characterized uniaxial strain loading conditions. The measured elastic wave amplitudes for the [110] and [111] orientations were lower for higher elastic impact stress (stress attained for an elastic diamond response), consistent with the result reported previously for [100] diamond. The maximum resolved shear stress (MRSS) on the {111}⟨110⟩ slip systems was determined for each orientation, revealing significant orientation dependence. The MRSS values for the [100] and [110] orientations (˜33 GPa) are 25%-30% of theoretical estimates; the MRSS value for the [111] orientation is significantly lower (˜23 GPa). Our results demonstrate that the MRSS depends strongly on the stress component normal to the {111} planes or the resolved normal stress (RNS), suggesting that the RNS plays a key role in inhibiting the onset of inelastic deformation. Lower elastic wave amplitudes at higher peak stress and the effect of the RNS are inconsistent with typical dislocation slip mechanisms of inelastic deformation, suggesting instead an inelastic response

  4. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  5. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  6. Exploring the Effects of Hope on GPA and Retention among College Undergraduate Students on Academic Probation

    Directory of Open Access Journals (Sweden)

    Holly Seirup

    2011-01-01

    Full Text Available This study analyzed the impact of hope on the academic achievement and retention of 235 students on academic probation at a private Northeastern university. Probationary students were enrolled in a mandatory online course designed to facilitate academic and nonacademic skills, to improve student GPAs and overall retention. The Hope Scale (Snyder et al. (1991 was administered to identify whether students with greater levels of hope would experience an increase in academic success upon completion of the course. Students were broken down into groups of high, medium, and low hope based on their scores on the instrument. Results showed students who completed the course were more likely to be retained than those who did not complete the course, had a slight increase in GPA by the end of the semester, and high-hope students showed the greatest overall gain in GPAs.

  7. SAT predicts GPA better for high ability subjects: Implications for Spearman's Law of Diminishing Returns.

    Science.gov (United States)

    Coyle, Thomas; Snyder, Anissa; Pillow, David; Kochunov, Peter

    2011-04-01

    This research examined the predictive validity of the SAT (formerly, the Scholastic Aptitude Test) for high and low ability groups. SAT scores and college GPAs were obtained from the 1997 National Longitudinal Survey of Youth. Subjects were classified as high or low ability by g factor scores from the Armed Services Vocational Aptitude Battery. SAT correlations with GPA were higher for high than low ability subjects. SAT g loadings (i.e., SAT correlations with g) were equivalent for both groups. This is the first study to show that the predictive validity of the SAT varies for ability groups that differ in g. The results contradict a presumption, based on Spearman's Law of Diminishing Returns, that a test's predictive validity should be lower for high ability subjects. Further research is needed to identify factors that contribute to the predictive validity of the SAT for groups that differ in g.

  8. Metal-Silicate Partitioning of Tungsten from 10 to 50 GPa

    Science.gov (United States)

    Shofner, G. A.; Campbell, A. J.; Danielson, L.; Rahman, Z.; Righter, K.

    2014-01-01

    Geochemical models of core formation are commonly based on core and mantle abundances of siderophile elements that partitioned between silicate and metal in a magma ocean in the early Earth. Tungsten is a moderately siderophile element that may provide constraints on the pressure, temperature, composition, and oxygen fugacity conditions, and on the timing of core formation in the Earth. Previous experimental studies suggest that pressure exerts little to no influence over W metal-silicate partitioning up to 24 GPa, and indicate that the stronger influences are temperature, composition, and oxygen fugacity. However, core formation models based in part on W, predict metal-silicate equilibration pressures outside the available experimental pressure range, requiring extrapolation of parameterized models. Therefore, higher pressure experimental data on W were needed to constrain this important parameter.

  9. THE RELATIONSHIP OF MBTI AND STUDENT GPA SCORE IN BINUS MANAGEMENT CLASS 2015

    Directory of Open Access Journals (Sweden)

    Son Wandrial

    2016-09-01

    Full Text Available This article identified the personality type of students by using MBTI models. There are 16 personality types in the MBTI. The method applied was the MBTI approach where the type and composition of the questionsrelated to the MBTI were taken from the Daft’s book. Questionnaires were distributed through discussion forum Binusmaya to all students in three classes that the writer taught. The questionnaires were distributed throughdiscussion forums, and there were about 158 students, but only 143 students who returned it. There were 41 male students and 102 female students. The result shows that the majority of students have approximately 51,04% introvert type and 58,04 % of students have the sensing type. The students with GPA more than 3,5 are ISFJ type.

  10. Preliminary deformation results to 12 GPa pressure using the Deformation-DIA

    Science.gov (United States)

    Mei, S.; Li, L.; Durham, W. B.; Wang, Y.; Uchita, T.; Getting, I. C.; Vaughan, M. T.; Weidner, D. J.; Burnley, P.

    2002-12-01

    High-pressure studies of the rheological behavior of Earth materials under high pressures are essential for understanding the dynamics of Earth's interior. However, outside of shock experiments and those in the diamond anvil cell, the highest working pressure for conventional deformation rigs (e.g., triaxial gas-medium apparatus, Griggs solid-medium apparatus) has been about 4 GPa. We report here first results from a new deformation apparatus called the deformation-DIA (D-DIA), a cubic-anvil, solid-medium apparatus specifically designed for constant-pressure deformation and capable of deforming samples at high temperatures (up to 2000 K) to pressures up to 15 GPa. Based on the cubic DIA apparatus, the D-DIA allows independent motion of the two vertical anvils to impose deformation on samples, and at the same time allows reverse motion on the four side anvils, thus preventing pressure from rising during deformation. Preliminary tests have been conducted on samples of NaCl, MgO, and olivine. The cold-pressed samples (1-2 mm in length and 1.2 mm in diameter), hard alumina pistons, and thermocouples form a 6-mm-long deformation column that is inserted into a graphite resistance heater within a 6-mm edge length cubic pressure medium, either pyrophyllite or boron epoxy. The cell is first squeezed hydrostatically to reach desired pressures and then deformed in compression at constant pressure. Experiments are carried out using synchrotron radiation, which makes it possible to measure sample length change and pressure in-situ to levels of x 10-5 to 4 x 10-4 s-1 over shortening strains of 10 - 30% at temperatures of 500 - 1200°C and pressures of 5 - 12 GPa. Pressure is monitored by the location of diffraction peaks of a small amount of well-characterized proxy material (often MgO) in the deformation column. Pressure is controlled manually by metering hydraulic fluid from the main ram (which drives the side anvils) at a rate such that diffraction pattern holds constant as

  11. Compressional behavior of solid NeHe2 up to 90 GPa

    International Nuclear Information System (INIS)

    Fukui, Hiroshi; Baron, Alfred Q R; Hirao, Naohisa; Ohishi, Yasuo

    2010-01-01

    NeHe 2 was compressed to about 90 GPa using a diamond anvil cell technique. The crystal structure was confirmed to be stable with hexagonal symmetry in the investigated pressure range and its p-V equation of state was determined by angular dispersive x-ray diffraction with synchrotron radiation. With the help of ab initio calculations, the compressibility and inter-atomic distances of NeHe 2 were compared with those of a helium and neon mixture of the same composition. This study shows that the bulk modulus of NeHe 2 is between those of neon and helium and that linear compressibilities of the inter-atomic distances are different from those of the elementary solids. This material can be a pressure-transmitting medium, providing both a large sample space and good quasi-hydrostatic conditions.

  12. The structure of CO2 hydrate between 0.7 and 1.0 GPa

    International Nuclear Information System (INIS)

    Tulk, C. A.; Molaison, J. J.; Machida, S.; Klug, D. D.; Lu, H.; Guthrie, M.

    2014-01-01

    A deuterated sample of CO 2 structure I (sI) clathrate hydrate (CO 2 ·8.3 D 2 O) has been formed and neutron diffraction experiments up to 1.0 GPa at 240 K were performed. The sI CO 2 hydrate transformed at 0.7 GPa into the high pressure phase that had been observed previously by Hirai et al. [J. Phys. Chem. 133, 124511 (2010)] and Bollengier et al. [Geochim. Cosmochim. Acta 119, 322 (2013)], but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO 2 molecules filling the water channels. This CO 2 +water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts a MH-III “like” filled ice structure with considerable disorder of the orientations of the CO 2 molecule. Furthermore, the disorder appears to be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al., our neutron diffraction data show that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO 2 hydrate transforms directly from the sI form to the filled ice structure

  13. The structure of CO2 hydrate between 0.7 and 1.0 GPa

    Science.gov (United States)

    Tulk, C. A.; Machida, S.; Klug, D. D.; Lu, H.; Guthrie, M.; Molaison, J. J.

    2014-11-01

    A deuterated sample of CO2 structure I (sI) clathrate hydrate (CO2.8.3 D2O) has been formed and neutron diffraction experiments up to 1.0 GPa at 240 K were performed. The sI CO2 hydrate transformed at 0.7 GPa into the high pressure phase that had been observed previously by Hirai et al. [J. Phys. Chem. 133, 124511 (2010)] and Bollengier et al. [Geochim. Cosmochim. Acta 119, 322 (2013)], but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO2 molecules filling the water channels. This CO2+water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts a MH-III "like" filled ice structure with considerable disorder of the orientations of the CO2 molecule. Furthermore, the disorder appears to be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al., our neutron diffraction data show that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO2 hydrate transforms directly from the sI form to the filled ice structure.

  14. Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 GPa and 1073 K

    Science.gov (United States)

    Chen, Ting; Liebermann, Robert C.; Zou, Yongtao; Li, Ying; Qi, Xintong; Li, Baosheng

    2017-08-01

    The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 GPa and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach 34% and 45% for P and S wave velocities, respectively, and 64% and 75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences on silica, d(lnVP)/d(SiO2) = 0.38 (wt %)-1 and d(lnVS)/d(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.

  15. Excellent durability of DLC film on carburized steel (JIS-SCr420) under a stress of 3.0 GPa

    International Nuclear Information System (INIS)

    Yakabe, F; Kumagai, M; Kuwahara, H; Ochiai, S; Jinbo, Y; Horiuchi, T

    2008-01-01

    To improve durability of transmission gears, Diamond Like Carbon (DLC) film coated on roller was estimated as well as TiN film. These films were coated on JIS-SCr420 steel, which was carburized, quenched, and tempered. DLC and TiN films were deposited by PCVD and PVD process, respectively. These surface modified rollers were estimated by usual metallurgical methods (observation of microstructure by optical microscope, SEM, and TEM, measurement of hardness by Vickers hardness tester and nano-indentator), measurement of friction coefficient by ball-on-disk in dry atmosphere, analysis of carbon by Raman spectroscopy and hydrogen by EDRA, and lifetime of pitting by the roller-pitting test. The hardness values were 21 GPa and 26 GPa, the elasticity coefficients were 192 GPa and 336 GPa, the friction coefficients were 0.1∼0.15 and 0.5∼0.6 for DLC and TiN films, respectively. The present DLC was a typical DLC called as hydrogenated amorphous carbon (a-C: H). The hydrogen content was about 20%. The surface fatigue resistance of DLC-coated specimen had 100 times longer life than that the carburized and quenched one even under Hertzian contact stress of 3.0 GPa. TiN coated specimen was failed at 3.0 GPa by 5.17·10 5 cycles despite that the strength of the surface of the substrate was reduced due to the exposure at higher temperature in the coating process than the temperature for tempering

  16. Single-crystal elasticity of MgAl2O4-spinel up to 10.9 GPa and 1000 K: Implication for the velocity structure of the top upper mantle

    Science.gov (United States)

    Duan, Yunfei; Li, Xinyang; Sun, Ningyu; Ni, Huaiwei; Tkachev, Sergey N.; Mao, Zhu

    2018-01-01

    The combined effect of pressure and temperature on the single-crystal elasticity of MgAl2O4-spinel has been studied using Brillouin scattering and X-ray diffraction up to 10.9 GPa and 1000 K in externally-heated diamond anvil cells. The obtained single-crystal elastic moduli of MgAl2O4-spinel at ambient conditions are consistent with literature values and follow a linear increase with pressure at high temperatures. More importantly, the pressure dependence of the elastic moduli at high temperatures is much smaller than that at 300 K, indicating a stronger temperature effect on the elastic moduli of MgAl2O4-spinel at high pressures. Our new results were applied to model the sound velocity of MgAl2O4-spinel at relevant pressure and temperature conditions of the top upper mantle, showing that MgAl2O4-spinel has the greatest velocity and the VP /VS ratio among major mantle minerals. We further modeled the velocity of spinel-peridotite at the top upper mantle. Varying the composition of spinel-peridotite can lead to up to 2.1% variation in VP and 1.3% in VS. The top upper mantle with greater VP and VS should contain more olivine and spinel but less orthopyroxene. The velocity of the top upper mantle is thus strongly correlated with the composition of the region. Our results are thus important in understanding the composition and velocity of the top upper mantle.

  17. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  18. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  19. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  20. Strongly correlating liquids and their isomorphs

    OpenAIRE

    Pedersen, Ulf R.; Gnan, Nicoletta; Bailey, Nicholas P.; Schröder, Thomas B.; Dyre, Jeppe C.

    2010-01-01

    This paper summarizes the properties of strongly correlating liquids, i.e., liquids with strong correlations between virial and potential energy equilibrium fluctuations at constant volume. We proceed to focus on the experimental predictions for strongly correlating glass-forming liquids. These predictions include i) density scaling, ii) isochronal superposition, iii) that there is a single function from which all frequency-dependent viscoelastic response functions may be calculated, iv) that...

  1. Optimization of strong and weak coordinates

    NARCIS (Netherlands)

    Swart, M.; Bickelhaupt, F.M.

    2006-01-01

    We present a new scheme for the geometry optimization of equilibrium and transition state structures that can be used for both strong and weak coordinates. We use a screening function that depends on atom-pair distances to differentiate strong coordinates from weak coordinates. This differentiation

  2. Polarization and Strong Infra-Red Activity in Compressed Solid Hydrogen

    OpenAIRE

    Souza, Ivo; Martin, Richard M.

    1998-01-01

    Under a pressure of ~150 GPa solid molecular hydrogen undergoes a phase transition accompanied by a dramatic rise in infra-red absorption in the vibron frequency range. We use the Berry's phase approach to calculate the electric polarization in several candidate structures finding large, anisotropic dynamic charges and strongly IR-active vibron modes. The polarization is shown to be greatly affected by the overlap between the molecules in the crystal, so that the commonly used Clausius-Mossot...

  3. An important role of temperature dependent scattering time in understanding the high temperature thermoelectric behavior of strongly correlated system: La0.75Ba0.25CoO3.

    Science.gov (United States)

    Singh, Saurabh; Kumar, Devendra; Pandey, Sudhir K

    2017-03-15

    In the present work, we report the temperature dependent thermopower (α) behavior of La 0.75 Ba 0.25 CoO 3 compound in the temperature range 300-600 K. Using the Heikes formula, the estimated value of α corresponding to high-spin configuration of Co 3+ and Co 4+ ions is found to be  ∼16 [Formula: see text], which is close to the experimental value, ∼13 [Formula: see text], observed at  ∼600 K. The temperature dependent TE behavior of the compound is studied by combining the WIEN2K and BoltzTrap code. The self consistency field calculations show that the compound have ferromagnetic ground state structure. The electronic structure calculations give half metallic characteristic with a small gap of  ∼50 meV for down spin channel. The large and positive value for down spin channel is obtained due to the unique band structure shown by this spin channel. The temperature dependent relaxation time for both the spin-channel charge carriers is considered to study the thermopower data in temperature range 300-600 K. For evaluation of α, almost linear values of [Formula: see text] and a non-linear values of [Formula: see text] are taken into account. By taking the temperature dependent values of relaxation time for both the spin channels, the calculated values of α using two current model are found to be in good agreement with experimental values in the temperature range 300-600 K. At 300 K, the calculated value of electrical conductivity by using the same value of relaxation time, i.e. 0.1 [Formula: see text] 10 -14 seconds for spin-up and [Formula: see text] seconds for spin-dn channel, is found to be equal to the experimentally reported value.

  4. Pressure dependence of the refractive index of diamond, cubic silicon carbide and cubic boron nitride

    Science.gov (United States)

    Balzaretti, N. M.; da Jornada, J. A. H.

    1996-09-01

    The pressure dependence of the refractive index of diamond, cubic boron nitride and cubic silicon carbide, was measured up to 9 GPa by an interferometric method using the diamond anvil cell. A least-square fit yields the following values for ( {1}/{n}) ( {dn }/{dP }): - 3.6 × 10 -4GPa -1 for diamond, -3.2 × 10 -4GPa -1 for c-BN and, for 3CSiC, -8.3 × 10 -4GPa -1. These results were used to investigate, for the first time under pressure, general empirical relationships between refractive index and energy gap found in the literature. The volume dependence of the electronic polarizability, α, of these compounds was determined through the Lorentz-Lorenz approach. The obtained linear behavior of α for the three cases was correlated to previous results for the pressure dependence of the transverse effective charge, e T∗.

  5. Quantum Hydrodynamical Formulation of Time-Dependent Density Functional Theory for Probing Strong-Field Multiphoton Processes: Application to the Study of High-Order Harmonic Generation of He and Ne in Intense Laser Fields

    Science.gov (United States)

    Roy, A. K.; Chu, Shih-I.

    2002-05-01

    We extend the quantum hydrodynamical (QFD) formulation of time-dependent density functional theory (TDDFT) to the study of multiphoton processes of many-electron atomic systems in intense laser fields (A. K. Roy and S. I. Chu, Phys. Rev. A (in press).). The QFD-TDDFT formulation results in a single generalized nonlinear Schrodinger equation (GNLSE) and includes the many-body effects through a local time-dependent exchange-correlation (xc) potential. The GNLSE is solved by the time- dependent generalized pseudospectral method (X. M. Tong and S.I. Chu, Chem. Phys. 217) (1997) 119. (X. Chu and S. I. Chu, Phys. Rev. A 63) (2001) 023411.. The procedure is applied to the study of multiphoton ionization (MPI) and high harmonic generation (HHG) of He and Ne in intense laser fields. Four different xc energy functionals are used in the study with an aim to explore the roles of exchange and correlation ovn MPI/HHG processes in details ^1.

  6. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  7. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  8. Relationship between mutation frequency of GPA locus and cumulative dose among medical diagnostic X-ray workers

    International Nuclear Information System (INIS)

    Wang Jixian; Yu Wenru; Li Benxiao; Fan Tiqiang; Li Zhen; Gao Zhiwei; Chen Zhenjun; Zhao Yongcheng

    2000-01-01

    Objective: To explore the feasibility of using GPA locus mutation assay as a bio-dosimeter for occupational exposure to ionizing radiation. Methods: An improved technique of GPA locus mutation assay was used in th study. The frequencies of mutant RBC in peripheral blood of 55 medical X-ray workers and 50 controls employed in different calendar-year periods were detected. The relationship between mutation frequencies (MFs) and period of entry, working years and cumulative doses were analyzed. Results: The MFs were significantly elevated among X-ray workers employed before 1970. This finding is similar to the result of cancer epidemiological study among medical X-ray workers , in which the cancer risk was significantly increased only X-ray workers employed before 1970. The MFs of GPA increased with increasing cumulative dose. The dose-effect relationship of Nφ MF with cumulative dose was closer than that of NN MF. Conclusion: There are many problems to be solved for using GPA MF assay as a bio-dosimeter such as individual variation, specificity and calibration curve of dose-effect relationship

  9. The Indirect Effect of Alcohol Use on GPA in First-Semester College Students: The Mediating Role of Academic Effort

    Science.gov (United States)

    Conway, James M.; DiPlacido, Joanne

    2015-01-01

    This study focused on first-semester college students, investigating (a) indirect effects of aggregate alcohol use on grade point average (GPA) through academic effort (skipping class and time on schoolwork) and (b) daily effects of alcohol use on reduced effort. Eighty students reported daily alcohol use and academic effort (skipping class and…

  10. The Differential Effects of Internship Participation on End-of-Fourth-Year GPA by Demographic and Institutional Characteristics

    Science.gov (United States)

    Parker, Eugene T., III.; Kilgo, Cindy A.; Sheets, Jessica K. Ezell; Pascarella, Ernest T.

    2016-01-01

    The purpose of this study is to explore the effects of internship participation on college students, specifically the effect on college GPA. Further, because of the capacity to disaggregate students by race in the sample, this study is significant because it provides much needed empirical evidence surrounding the impact of participation in…

  11. Use of the glycophorin A somatic mutation assay for rapid, unambiguous identification of Fanconi anemia homozygotes regardless of GPA genotype.

    Science.gov (United States)

    Evdokimova, Viktoria N; McLoughlin, Reagan K; Wenger, Sharon L; Grant, Stephen G

    2005-05-15

    A 7-year-old girl was hospitalized with pancytopenia requiring blood transfusion. She and an older brother with suspicious symptoms were referred for laboratory testing to confirm a clinical diagnosis of Fanconi anemia (FA). Blood samples from these two children and one parent were examined with the GPA somatic mutation assay. The patient's total GPA somatic mutation frequency of 1.4 x 10(-4) was determined despite the confounding effects of her recent transfusion, and was greater than 10-fold higher than that of a population of pediatric controls, consistent with the known FA phenotype. Her brother was not informative for the standard GPA assay, which requires heterozygosity for the MN blood group, but was analyzed with a modified assay that measured only allele loss mutation. His mutation frequency, 6.8 x 10(-4) was also supportive of a diagnosis of FA. Both analyses also showed evidence of ongoing mutation through terminal erythroblast differentiation, a characteristic of patients with DNA repair syndromes which further confirmed the diagnoses. These conclusions were confirmed with traditional DEB-induced chromosome breakage studies. The quantitative and qualitative aspects of the GPA assay relevant for applying this test for FA diagnosis, and perhaps for carrier detection, are discussed. (c) 2005 Wiley-Liss, Inc., A Wiley Company.

  12. Indicators of Postsecondary Employment and Education for Youth with Disabilities in Relation to GPA and General Education

    Science.gov (United States)

    McConnell, Amber E.; Martin, James E.; Hennessey, Maeghan N.

    2015-01-01

    This study examined the relations among research-identified non-academic indicators of post-school education and employment measured by the Transition Assessment and Goal Generator (TAGG), student grade point average (GPA), and percentage of time students with disabilities received instruction in the general education classroom. Participants…

  13. 40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?

    Science.gov (United States)

    2010-07-01

    ... Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA? (a) The refinery or importer annual average sulfur standard for gasoline produced or imported for use...), shall be 150.00 ppm. (b) The per-gallon cap standard for gasoline produced or imported for use in the...

  14. Chemokine receptor co-expression reveals aberrantly distributed T-H effector memory cells in GPA patients

    NARCIS (Netherlands)

    Lintermans, Lucas L.; Rutgers, Abraham; Stegeman, Coen A.; Heeringa, Peter; Abdulahad, Wayel H.

    2017-01-01

    Background: Persistent expansion of circulating CD4(+) effector memory T cells (TEM) in patients with granulomatosis with polyangiitis (GPA) suggests their fundamental role in disease pathogenesis. Recent studies have shown that distinct functional CD4(+) TEM cell subsets can be identified based on

  15. Molecular contest between potato and the potato cyst nematode Globodera pallida: modulation of Gpa2-mediated resistance

    NARCIS (Netherlands)

    Koropacka, K.B.

    2010-01-01

    Gpa2 recognition specificity
    Among all the multicellular animals, nematodes are the most numerous. In soil, a high variety
    of free living nematodes feeding on bacteria can be found as well as species that parasitize
    insects, animals or plants. The potato cyst nematode (PCN)

  16. Time-resolved light emission of a, c, and r-cut sapphires shock-compressed to 65 GPa

    Science.gov (United States)

    Liu, Q. C.; Zhou, X. M.

    2018-04-01

    To investigate light emission and dynamic deformation behaviors, sapphire (single crystal Al2O3) samples with three crystallographic orientations (a, c, and r-cut) were shock-compressed by the planar impact method, with final stress ranges from 47 to 65 GPa. Emission radiance and velocity versus time profiles were simultaneously measured with a fast pyrometer and a Doppler pin system in each experiment. Wave profile results show anisotropic elastic-plastic transitions, which confirm the literature observations. Under final shock stress of about 52 GPa, lower emission intensity is observed in the r-cut sample, in agreement with the previous report in the literature. When final shock stress increases to 57 GPa and 65 GPa, spectral radiance histories of the r-cut show two stages of distinct features. In the first stage, the emission intensity of r-cut is lower than those of the other two, which agrees with the previous report in the literature. In the second stage, spectral radiance of r-cut increases with time at much higher rate and it finally peaks over those of the a and c-cut. These observations (conversion of intensified emission in the r-cut) may indicate activation of a second slip system and formation of shear bands which are discussed with the resolved shear stress calculations for the slip systems in each of the three cuts under shock compression.

  17. Associations between baccalaureate nursing students' perceptions of educational environment and HESI scores and GPA.

    Science.gov (United States)

    Payne, Leslie K; Glaspie, Tina

    2014-06-01

    Students' perceptions of their educational environment have been found to be related to their approaches to learning and learning outcomes. Educational environment is just beginning to be researched in nursing education with the vast majority of studies focusing on the clinical educational environment. Perception of educational environment has been shown to influence student implementation of a specific learning style and influences educational outcomes such as program completion and GPA. There is a need for sound research that explores the relationship, if any, between perceptions of environment and outcomes. To explore the relationship between baccalaureate nursing student (BSN) perception of educational environment (SPEE) and objective learning outcomes. Retrospective correlational descriptive study. Private School of Nursing in the Southwest. Convenience sample of 62 graduating baccalaureate students. All graduating BSN students were invited to complete the Dundee Ready Education Environment Measure (DREEM) through the online survey application Qualtrics. A total of 62 students completed the DREEM survey. These results were compared with each student's GPA and HESI score. A total of 62 students completed the survey for an overall response rate of 57%. There was no correlation between total SPEE and nursing grade point average (NGPA) or HESI exit scores. Based on this study at this institution, it appears that students' performance was not influenced by SPEE. One of the major implications of this study is the possibility that an "acceptable" SPEE (one that is neither exceptional nor terrible) may not significantly influence student outcomes. Exploring this relationship has theoretical as well as practical implications as educators seek to determine the effectiveness of educational interventions. Student perception of learning environment is measured in various ways at the majority of institutions. It has been assumed that an educational environment that is

  18. Elastic and Vibrational Properties of FeO to 100 GPa

    Science.gov (United States)

    Diamond, M. R.; Wicks, J. K.; Jackson, J. M.; Sturhahn, W.; Zhang, D.

    2012-12-01

    The large chemical, density, and dynamical contrasts associated with the juxtaposition of a liquid iron-dominant alloy and silicates at the core-mantle boundary (CMB) are associated with a rich range of complex seismological features. Seismic heterogeneity at this boundary includes small patches of anomalously low sound velocities, called ultralow-velocity zones (ULVZs). Their small size (5 to 40 km thick) and depth (~2800 km) present unique challenges for seismic characterization and geochemical interpretation. Previous research has indicated iron-rich (Mg,Fe)O may be present near the CMB and play a major role in the evolution of this boundary layer. The fact that (Mg,Fe)O has enhanced stability and a high density also indicate the likelihood of its existence near Earth's core-mantle boundary. However, there are few constraints on the sound velocities and thermodynamic properties of iron end-member (Mg,Fe)O, namely wüstite or FeO, at conditions approaching those of the CMB. We determined the equation of state, sound velocities, and thermodynamic properties related to the Fe-participating lattice vibrations of FeO using x-ray diffraction and nuclear resonant scattering techniques up to 100 GPa at 300 K. The experiments were conducted using diamond-anvil cells and powdered 57Fe-enriched FeO. Powder x-ray diffraction experiments were conducted using neon as a pressure medium (and marker) and ruby as an additional pressure marker at the Advanced Light Source of Lawrence Berkeley National Laboratory, California. By observing the 2-theta values of the x-ray reflections of FeO, we determined the volume of the sample for each pressure. By combining these results with nuclear resonant scattering measurements on FeO at the Advanced Photon Source of Argonne National Laboratory, we constrain the elasticity, vibrational properties, and spin state of FeO up to 100 GPa. These results represent a step towards understanding the complete thermodynamic properties of FeO under the

  19. High antibody-dependent cellular cytotoxicity responses are correlated with strong CD8 T cell viral suppressive activity but not with B57 status in HIV-1 elite controllers.

    Directory of Open Access Journals (Sweden)

    Olivier Lambotte

    Full Text Available The role of Antibody-dependent cellular cytotoxicity (ADCC responses in HIV-1 controllers is still unclear due to the heterogeneity of these patients. We analyzed 67 HIV-1 controllers and found significantly higher levels of ADCC antibodies in controllers versus viremic subjects (p = 0.017. Moreover, multivariate analysis revealed significantly higher ADCC titers in HLA B57- controllers compared to HLA-B57+ ones (p = 0.0086. These data suggest a role for ADCC in immune control of HIV, especially in HLA B57 negative controllers.

  20. Ultra-thin and strong formvar-based membranes with controlled porosity for micro- and nano-scale systems

    Science.gov (United States)

    Auchter, Eric; Marquez, Justin; Stevens, Garrison; Silva, Rebecca; Mcculloch, Quinn; Guengerich, Quintessa; Blair, Andrew; Litchfield, Sebastian; Li, Nan; Sheehan, Chris; Chamberlin, Rebecca; Yarbro, Stephen L.; Dervishi, Enkeleda

    2018-05-01

    We present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%–65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizations including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m‑1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ∼50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.

  1. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  2. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  3. Progress towards materials science above 1000 GPa (10 Mbar) on the NIF laser

    International Nuclear Information System (INIS)

    Remington, B.A.; Park, H.; Prisbrey, S.T.; Pollaine, S.M.; Cavallo, R.M.; Rudd, R.E.; Lorenz, K.T.; Becker, R.; Bernier, J.; Barton, N.; Arsenlis, T.; Glendinning, S.G.; Hamza, A.; Swift, D.; Jankowski, A.; Meyers, M.A.

    2009-01-01

    Solid state dynamics experiments at extreme pressures, P > 1000 GPa (10 Mbar), and ultrahigh strain rates (1.e6-1.e8 1/s) are being developed for the National Ignition Facility (NIF) laser. These experiments will open up exploration of new regimes of materials science at an order of magnitude higher pressures than have been possible to date. Such extreme, solid state conditions can be accessed with a ramped pressure drive. The experimental, computational, and theoretical techniques are being developed and tested on the Omega laser. Velocity interferometer measurements (VISAR) establish the high pressure conditions generated by the ramped drive. Constitutive models for solid state strength under these conditions are tested by comparing simulations with experiments measuring perturbation growth from the Rayleigh-Taylor instability in solid state samples of vanadium. Radiography techniques using synchronized bursts of x-rays have been developed to diagnose this perturbation growth. Experiments on Omega demonstrating these techniques at peak pressures of ∼1 Mbar will be discussed. The time resolved observation of foil cracking and void formation show the need for tamped samples and a planar drive

  4. The principal Hugoniot of Mg2SiO4 to 950 GPa

    Science.gov (United States)

    Townsend, J. P.; Root, S.; Shulenburger, L.; Lemke, R. W.; Kraus, R. G.; Jacobsen, S. B.; Spaulding, D.; Davies, E.; Stewart, S. T.

    2017-12-01

    We present new measurements and ab-initio calculations of the principal Hugoniot states of forsterite Mg2SiO4 in the liquid regime between 200-950 GPa.Forsterite samples were shock compressed along the principal Hugoniot using plate-impact shock compression experiments on the Sandia National Laboratories Z machine facility.In order to gain insight into the physical state of the liquid, we performed quantum molecular dynamics calculations of the Hugoniot and compare the results to experiment.We show that the principal Hugoniot is consistent with that of a single molecular fluid phase of Mg2SiO4, and compare our results to previous dynamic compression experiments and QMD calculations.Finally, we discuss how the results inform planetary accretion and impact models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  5. Elasticity of cerium up to 4.4 GPa by sound velocity measurements under hydrostatic pressure

    International Nuclear Information System (INIS)

    Wang, Zhigang; Bi, Yan; Xu, Liang; Liu, Lei

    2014-01-01

    We report here the longitudinal and shear sound velocities on polycrystalline cerium under hydrostatic pressure across the iso-structural γ-α phase transition up to 4.4 GPa. Comparing with previous methods, the pressure-density relation of Ce has been calculated by integrating with the initial travel time and pressure without any fitting. The pressure correction of the Grüneisen parameter and linear expansion coefficient are taken into account during the integration process. The sound velocities, bulk modulus, shear modulus, Debye temperature, and vibrational entropy are achieved and have been compared with previous results. The bulk modulus of cerium in α phase agrees with the previous results determined by neutron and x-ray diffraction. The Debye temperature above and below the phase transition are θ D γ =130.9 K and θ D α =151.9 K, respectively. The difference of the Debye temperature from respective experiment is found and has been expounded. We consider that the vibrational entropy change per atom of 0.44 k B as the Kondo collapse of 17% volume change, and 0.70 k B as the total change from γ phase to complete α phase. (papers)

  6. Elasticity of cerium up to 4.4 GPa by sound velocity measurements under hydrostatic pressure

    Science.gov (United States)

    Wang, Zhigang; Bi, Yan; Xu, Liang; Liu, Lei

    2014-04-01

    We report here the longitudinal and shear sound velocities on polycrystalline cerium under hydrostatic pressure across the iso-structural γ-α phase transition up to 4.4 GPa. Comparing with previous methods, the pressure-density relation of Ce has been calculated by integrating with the initial travel time and pressure without any fitting. The pressure correction of the Grüneisen parameter and linear expansion coefficient are taken into account during the integration process. The sound velocities, bulk modulus, shear modulus, Debye temperature, and vibrational entropy are achieved and have been compared with previous results. The bulk modulus of cerium in α phase agrees with the previous results determined by neutron and x-ray diffraction. The Debye temperature above and below the phase transition are \\theta _{D}^{\\gamma }=130.9\\;{\\rm{K}} and \\theta _{D}^{\\alpha }=151.9\\;{\\rm{K}}, respectively. The difference of the Debye temperature from respective experiment is found and has been expounded. We consider that the vibrational entropy change per atom of 0.44 k B as the Kondo collapse of 17% volume change, and 0.70 k B as the total change from γ phase to complete α phase.

  7. SADC Mediation in Zimbabwe's Global Political Agreement (GPA: A Reflection on Opportunities and Complexities

    Directory of Open Access Journals (Sweden)

    Modeni M. Sibanda

    2014-06-01

    Full Text Available This article analyses the opportunities and complexities of the SADC mediation in Zimbabwe’s Global Political Agreement (GPA in facilitating and operationalising theprinciples and values of peace, security, human rights and democracy as set out in Article 4 of the SADC treaty. It attempts to interrogate the extent to which the regional grouping’s mechanisms for enforcing its principles and values have been successful.   The article argues that despite SADC’s noble commitment to promoting the development of democratic institutions and practices, as well as encouraging the observance of universal human rights, peace and security, the resolution of the Zimbabwe crisis shows that, in practice, the operationalisation of SADC protocol principles and values have been a sorry saga of delays, secrecy, purported agreements and nothing concrete coming out of it.  Using the Zimbabwe case study, this article further argues that SADC either lacks appropriate power and authority or is reluctant to hold member states accountable.  This seems so, given that as a regional body, it has allowed itself to be utterly inadequate to the task envisioned by the organ in resolving the Zimbabwe crisis. The paper concludes that the sum of all this has had the effect of exposing SADC and it being perceived as a weak regional organisation.

  8. Phase relations in the hydrous CMAS pyrolite in presence of KCl at 2 GPa

    Science.gov (United States)

    Safonov, O.

    2012-04-01

    In the upper mantle, chlorides are constituents of concentrated aqueous solutions (brines), as well as chloride-carbonate and carbonatite melts. Mineral assemblages coming from diverse depth levels show that mobile (K, Na)Cl-bearing fluids are able to provoke intensive metasomatism of the peridotitic mantle accompanied by melting. Scarce experimental studies on influence of brines on mineral equilibria in the peridotitic mantle (Stalder et al., 2008; Chu et al., 2011) indicate that influence of chlorides on water activity in a fluid equilibrated with forsterite enstatite at pressures above 2 GPa is very similar to their effect at lower "crustal" pressures (e.g. Aranovich, Newton, 1997): decrease of the H2O activity with an increase of the salt content results in an increase of the melting temperature of silicates. Nevertheless, these experiments were performed in the Al-free systems. Presence of Al would provoke an active interaction of alkali chlorides, namely KCl, with silicates with formation of new K-Al-bearing phases, such as phlogopite (in presence of H2O), which would influence on the melting of complex assemblages. In order to investigate an effect of KCl on phase relations in the Al2O3, CaO, Na2O-rich hydrous peridotite and on stability of garnet, pyroxenes, and amphiboles, in particular, experiments on interaction of the model CMAS pyrolite Fo57En17Prp14Di12 (+0.3 wt. % of Na2O) with the H2O-KCl fluid were performed at 2 GPa in the temperature interval 900-1200. Mixtures of synthetic forsterite, diopside, enstatite and pyrope in the above weight ratio were mixed with 14 wt. % of Mg(OH)2 corresponding to 4.4 wt. % of H2O in the system. 2.4, 3.7, 5 and 10 wt. % of KCl were added to silicate-H2O mixture. Experiments were performed using a piston-cylinder apparatus with ½-inch talc high-pressure cells calibrated via brucite = periclase + H2O and albite = jadeite + quartz equilibria curves. Temperature was controlled with accuracy ?1 with the W95Re5/W80Re20

  9. Shock compression of liquid carbon monoxide and methane to 90 GPa (900 kbar)

    International Nuclear Information System (INIS)

    Nellis, W.J.; Ree, F.H.; van Thiel, M.; Mitchell, A.C.

    1981-01-01

    Dynamic equation-of-state data for liquid CO and CH 4 were measured in the shock pressure range 5--92 GPa (50--920 kbar) using a two-stage light-gas gun. The liquids were shocked from initial states near their saturation curves at 77 and 111 K for CO and CH 4 , respectively. The experimental technique used to double-shock CH 4 is described. The CO data were examined by using three theoretical models: (1) a chemically nonreactive model, (2) a quasi-chemical-equilibrium model that allows CO to dissociate into gaseous species and graphite, and (3) a chemical-equilibrium model that also includes a dense carbon phase which exists at higher pressures and temperatures than graphite. This dense phase is assumed to be diamond. Our analysis shows that at low pressure chemical equilibrium takes much longer than a typical shock passage time. As a consequence, the experimental data initially follow the nonreactive Hugoniot to pressures well beyond the chemical dissociation limit. Both the experimental data and the Hugoniot computed with case (3) agree satisfactorily at high pressure. Further consequences of these observations to high-explosive studies are discussed. The theoretical analysis for the CH 4 data was presented in an earlier paper

  10. Structural stability and mechanism of compression of stoichiometric B13C2up to 68GPa.

    Science.gov (United States)

    Chuvashova, Irina; Bykova, Elena; Bykov, Maxim; Svitlyk, Volodymyr; Dubrovinsky, Leonid; Dubrovinskaia, Natalia

    2017-08-21

    Boron carbide is a ceramic material with unique properties widely used in numerous, including armor, applications. Its mechanical properties, mechanism of compression, and limits of stability are of both scientific and practical value. Here, we report the behavior of the stoichiometric boron carbide B 13 C 2 studied on single crystals up to 68 GPa. As revealed by synchrotron X-ray diffraction, B 13 C 2 maintains its crystal structure and does not undergo phase transitions. Accurate measurements of the unit cell and B 12 icosahedra volumes as a function of pressure led to conclusion that they reduce similarly upon compression that is typical for covalently bonded solids. A comparison of the compressional behavior of B 13 C 2 with that of α-B, γ-B, and B 4 C showed that it is determined by the types of bonding involved in the course of compression. Neither 'molecular-like' nor 'inversed molecular-like' solid behavior upon compression was detected that closes a long-standing scientific dispute.

  11. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  12. 40 CFR 80.540 - How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007...

    Science.gov (United States)

    2010-07-01

    ... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline... may apply to EPA for approval to produce gasoline subject to the GPA standards in 2007 and 2008. Such...

  13. Demographic and Psychological Predictors of Grade Point Average (GPA) in North-Norway: A Particular Analysis of Cognitive/School-Related and Literacy Problems

    Science.gov (United States)

    Saele, Rannveig Grøm; Sørlie, Tore; Nergård-Nilssen, Trude; Ottosen, Karl-Ottar; Goll, Charlotte Bjørnskov; Friborg, Oddgeir

    2016-01-01

    Approximately 30% of students drop out from Norwegian upper secondary schools. Academic achievement, as indexed by grade point average (GPA), is one of the strongest predictors of dropout. The present study aimed to examine the role of cognitive, school-related and affective/psychological predictors of GPA. In addition, we examined the…

  14. High Pressure In Situ X-ray Diffraction Study of MnO to 120 GPa and Comparison with Shock Compression Experiment

    Science.gov (United States)

    Yagi, Takehiko; Kondo, Tadashi; Syono, Yasuhiko

    1997-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment (Syono et al., this symposium), high pressure in situ x-ray experiments were carried out up to 120 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil and x-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase into hexagonal unit cell was observed from 25-40 GPa, which continues to increase up to 90 GPa. At around 90 GPa, discontinuous change of the diffraction was observed. This new phase cannot be explained by a simple B2 structure and the analysis of this phase is in progress. This high pressure phase has metallic appearance, which reverses to transparent MnO on release of pressure.

  15. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  16. Radial X-ray diffraction study of the static strength and equation of state of MoB2 to 85 GPa

    International Nuclear Information System (INIS)

    Xiong, Lun; Liu, Jing; Zhang, Xinxin; Tao, Qiang; Zhu, Pinwen

    2015-01-01

    Highlights: • α-MoB 2 powder synthesized under high pressure–temperature condition. • We have firstly investigated the equation of state of α-MoB 2 under uniaxial compression up to 85 GPa. • The complete elastic constant tensor of α-MoB 2 at high pressures up to 100 GPa are firstly calculated from density-functional theory (DFT). • We have investigated the strength of α-MoB 2 under uniaxial compression up to 85 GPa. - Abstract: Investigations of strength and equation of state of α-MoB 2 have been performed under nonhydrostatic compression up to 85 GPa using an angle-dispersive radial X-ray diffraction (RXD) techniques together with the lattice strain theory in a 2-fold panoramic diamond anvil cell at ambient temperature. The RXD data yields a bulk modulus and its pressure derivative as K 0 = 323(6) GPa with K 0 ′ = 4.59(27). The ratio of t/G is found to remain constant above ∼44 GPa, indicating that the α-MoB 2 started to experience yield with plastic deformation at this pressure. Together with theoretical results on high-pressure shear modulus, our results here show that molybdenum diborides sample could support a differential stress of ∼18 GPa when it started to yield with plastic deformation at ∼44 GPa under uniaxial compression. A maximum differential stress, as high as ∼25 GPa can be supported by molybdenum diborides at the high pressure of ∼85 GPa

  17. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

    Science.gov (United States)

    Gallington, Leighanne C.; Hester, Brett R.; Kaplan, Benjamin S.; Wilkinson, Angus P.

    2017-05-01

    Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP2O7 family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV2O7 and HfV2O7 were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV2O7 and HfV2O7 exhibited a very strong dependence on pressure (∼700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV2O7 was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively).

  18. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

    Energy Technology Data Exchange (ETDEWEB)

    Gallington, Leighanne C.; Hester, Brett R.; Kaplan, Benjamin S.; Wilkinson, Angus P. (GIT)

    2017-05-01

    Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP2O7 family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV2O7 and HfV2O7 were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV2O7 and HfV2O7 exhibited a very strong dependence on pressure (~700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV2O7 was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively).

  19. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion require us to understand electrochemistry on the scale of a single atom; and we already know that the only prospect for effective high temperature superconductivity involves strongly correlated materials. Even novel IT technologies are now seen to have value not just for novel function but also for efficiency. While strongly correlated electron systems continue to excite researchers and the public alike due to the fundamental science issues involved, it seems increasingly likely that support for the science will be leveraged by its impact on energy and sustainability. Strongly correlated electron systems contents Strongly correlated electron systemsSiddharth S Saxena and P B Littlewood Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metalsF Steglich, J Arndt, O Stockert, S Friedemann, M Brando, C Klingner, C Krellner, C Geibel, S Wirth, S Kirchner and Q Si High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyN L Wang, W Z Hu, Z G Chen, R H Yuan, G Li, G F Chen and T Xiang Structural investigations on YbRh2Si2: from the atomic to the macroscopic length scaleS Wirth, S Ernst, R Cardoso-Gil, H Borrmann, S Seiro, C Krellner, C Geibel, S Kirchner, U Burkhardt, Y Grin and F Steglich Confinement of chiral magnetic

  20. Pressure-dependent measurements in superconductors

    Science.gov (United States)

    Suresh, N.; Tallon, J. L.

    2008-07-01

    To evaluate the performance of a home-built miniature non-magnetic piston clamp cell we have carried out extensive low-temperature (1.5 to 10 K) measurements of the critical field, Hc, for the element Pb up to a pressure of P = 1.2 GPa. Surprisingly, such data has not previously been reported above 0.3 GPa. From this data the electronic entropy, specific heat, thermal expansion coefficient and compressibility is calculated as a function of temperature, pressure and magnetic field. The zero-field data is consistent with direct thermodynamic measurements and the P-dependence of Tc and specific heat coefficient, γ(T, P), allows the determination of the P-dependence of the pairing interaction. Using Pb as a manometer we investigated the pressure dependence of oxygen isotope effect on Tc for YBa2Cu4O8.

  1. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  2. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  3. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  4. FOREWORD: CCM Second International Seminar: Pressure Metrology from 1 kPa to 1 GPa

    Science.gov (United States)

    Molinar, G. F.

    1994-01-01

    The Comité Consultatif pour la Masse et les Grandeurs Apparentées (CCM), through its High Pressure and Medium Pressure Working Groups, organized this Second International Seminar on Pressure Metrology from 1 kPa to 1 GPa, which was held at the Laboratoire National d'Essais (LNE), Paris, France, from 2 to 4 June 1993. The scope of the seminar was to review the state of the art of pressure measurements in the 1 kPa to I GPa pressure range and to present innovative contributions by standards laboratories, universities and industry. The seminar was organized in six sessions: liquid-column manometers; piston gauge pressure standards; properties of liquids and gases relevant to pressure metrology; pressure transducers and transfer standards; pressure standard comparison (methods and results); dynamic pressure measurements. Each session opened with the presentation of a review paper on major requirements in that field and, at the end of the seminar, a general discussion was organized on the actual limits of accuracy of static and dynamic pressure measurements in fluid media, and the fundamental problems in pressure metrology between 1 kPa and 1 GPa. The seminar was attended by sixty scientists from twenty-four countries, all working in the field of pressure measurements. Forty-nine papers were presented. The participation of scientists from so many countries indicates the importance of pressure metrology from the scientific and industrial points of view. Most papers were presented by scientists from national standards laboratories, with eight papers from universities and four from industry. Eleven papers reported the results of cooperative work involving metrological institutions dealing with high pressure, generally national standards laboratories, an indication that scientific links are already well established at this level. Links are also strengthening between industry and standards laboratories. Although industrial participation at the seminar was relatively small

  5. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  6. Electrical conductivity and equation of state of liquid nitrogen, oxygen, benzene, and 1-butene shocked to 60 GPa

    International Nuclear Information System (INIS)

    Hamilton, D.C.

    1986-01-01

    Measurements are reported for the electrical conductivity of liquid nitrogen (N 2 ), oxygen (O 2 ) and benzene (C 6 H 6 ), and Hugoniot equation of state of liquid 1-butene (C 4 H 8 ) under shock compressed conditions. The conductivity data span 7 x 10 -4 to 7 x 10 1 Ω -1 cm -1 over a dynamic pressure range 18.1 to 61.5 GPa and are discussed in terms of amorphous semiconduction models which include such transport phenomena as hopping, percolation, pseudogaps, and metallization. Excellent agreement is found between the equation-of-state measurements, which span a dynamic pressure range 12.3 to 53.8 GPa, and Ree's calculated values which assume a 2-phase mixture consisting of molecular hydrogen and carbon in a dense diamond-like phase. There is a 2-1/2 fold increase in the thermal pressure contribution over a less dense, stoichiometrically equivalent liquid. 90 refs., 48 figs., 8 tabs

  7. The predictive ability of critical thinking, nursing GPA, and SAT scores on first-time NCLEX-RN performance.

    Science.gov (United States)

    Romeo, Elizabeth M

    2013-01-01

    This study was conducted to investigate the predictability of several variables in achieving first-time success on the NCLEX-RN. Several researchers have attempted to investigate the differences between students who passed the NCLEX-RN the first time and those who failed. No studies used a large enough failure group to have statistical significance. The three specific variables in this study were nursing GPA, SAT combined math and verbal scores, and critical thinking measured on a standardized assessment examination. An ex post facto study design was used to examine data from the records of associate degree nursing graduates during a three-year period. The most significant predictors of NCLEX-RN success were the students' nursing GPA and the overall standardized assessment examination score. The findings of this study could potentially influence the identification of students at risk for NCLEX-RN failure.

  8. Individual differences in the consideration of future consequences scale correlate with sleep habits, sleep quality, and GPA in university students.

    Science.gov (United States)

    Peters, Brandon R; Joireman, Jeff; Ridgway, Richard L

    2005-06-01

    The present study examined relationships between individual differences in the consideration of future consequences, sleep habits and sleep quality, and academic achievement in a sample of 231 undergraduates, 156 women and 75 men, whose ages ranged from 18 to 41 years (M = 19.0 yr., SD=2.82). Individuals were recruited from two introductory courses and two upper-division courses, one each in the fields of biology and psychology. An 8-page questionnaire was administered to assess variables relating to personality, sleep habits and quality, and grade point average (GPA). Each volunteer was given extra credit in their respective courses for participation. Higher scores on the Consideration of Future Consequences scale were associated with self-reported measures of more regular sleep schedules, greater satisfaction with sleep, a reduced likelihood of oversleeping, and higher grade point averages. Moreover, oversleeping was significantly correlated with both scale scores and GPA.

  9. Effect of the fcc-hcp martensitic transition on the equation of state of solid krypton up to 140 GPa

    Science.gov (United States)

    Rosa, A. D.; Garbarino, G.; Briggs, R.; Svitlyk, V.; Morard, G.; Bouhifd, M. A.; Jacobs, J.; Irifune, T.; Mathon, O.; Pascarelli, S.

    2018-03-01

    Solid krypton (Kr) undergoes a pressure-induced martensitic phase transition from a face-centered cubic (fcc) to a hexagonal close-packed (hcp) structure. These two phases coexist in a very wide pressure domain inducing important modifications of the bulk properties of the resulting mixed phase system. Here, we report a detailed in situ x-ray diffraction and absorption study of the influence of the fcc-hcp phase transition on the compression behavior of solid krypton in an extended pressure domain up to 140 GPa. The onset of the hcp-fcc transformation was observed in this study at around 2.7 GPa and the coexistence of these two phases up to 140 GPa, the maximum investigated pressure. The appearance of the hcp phase is also evidenced by the pressure-induced broadening and splitting of the first peak in the XANES spectra. We demonstrate that the transition is driven by a continuous nucleation and intergrowth of nanometric hcp stacking faults that evolve in the fcc phase. These hcp stacking faults are unaffected by high-temperature annealing, suggesting that plastic deformation is not at their origin. The apparent small Gibbs free-energy differences between the two structures that decrease upon compression may explain the nucleation of hcp stacking faults and the large coexistence domain of fcc and hcp krypton. We observe a clear anomaly in the equation of state of the fcc solid at ˜20 GPa when the proportion of the hcp form reaches ˜20 % . We demonstrate that this anomaly is related to the difference in stiffness between the fcc and hcp phases and propose two distinct equation of states for the low and high-pressure regimes.

  10. Thermodynamic data and modeling of the water and ammonia-water phase diagrams up to 2.2 GPa for planetary geophysics.

    Science.gov (United States)

    Choukroun, Mathieu; Grasset, Olivier

    2010-10-14

    We present new experimental data on the liquidus of ice polymorphs in the H(2)O-NH(3) system under pressure, and use all available data to develop a new thermodynamic model predicting the phase behavior in this system in the ranges (0-2.2 GPa; 175-360 K; 0-33 wt % NH(3)). Liquidus data have been obtained with a cryogenic optical sapphire-anvil cell coupled to a Raman spectrometer. We improve upon pre-existing thermodynamic formulations for the specific volumes and heat capacities of the solid and liquid phase in the pure H(2)O phase diagram to ensure applicability of the model in the low-temperature metastable domain down to 175 K. We compute the phase equilibria in the pure H(2)O system with this new model. Then we develop a pressure-temperature dependent activity model to describe the effect of ammonia on phase transitions. We show that aqueous ammonia solutions behave as regular solutions at low pressures, and as close-to-ideal solutions at pressure above 600 MPa. The computation of phase equilibria in the H(2)O-NH(3) system shows that ice III cannot exist at concentrations above 5-10 wt % NH(3) (depending on pressure), and ice V is not expected to form above 25%-27% NH(3). We eventually address the applications of this new model for thermal and evolution models of icy satellites.

  11. X-ray diffraction measurements on CuGeO3 under high pressures to 81 GPa using synchrotron radiation and imaging plates

    International Nuclear Information System (INIS)

    Ming, L C; Eto, T; Takeda, K; Kobayashi, Y; Suzuki, E; Endo, S; Sharma, S K; Jayaraman, A; Kikegawa, T

    2002-01-01

    Angle-dispersive x-ray diffraction measurements using CuGeO 3 (I) and CuGeO 3 (III) as the starting materials were carried out to 81 and 31 GPa, respectively, at room temperature. Data for phase (I) show that phase transitions occur at ∼7, ∼14, and ∼22 GPa, respectively, corresponding to (I) → (II), (II) → (II'), and (II') → (VI) transitions, as reported previously. The tetragonal phase (VI) was found to be stable up to 81 GPa, the highest pressure determined in this study. The volume changes at the transition pressures are estimated to be of ∼5%, ∼0%, and ∼14% for (I) → (II), (II) → (II'), and (II') → (VI) transitions, respectively. Data from measurements where phase (III) was the starting material show that phase (III) first changes to phase (IV) at ∼7 GPa and then to (IV') at 13.5 GPa, and finally to phase (V) at ∼18 GPa, with volume changes of 1.5%, 0%, and 20%, respectively, at the transition pressure. The volume change of 20% at 18 GPa is consistent with the pyroxene-perovskite transition

  12. The lambda sigma calculus and strong normalization

    DEFF Research Database (Denmark)

    Schack-Nielsen, Anders; Schürmann, Carsten

    Explicit substitution calculi can be classified into several dis- tinct categories depending on whether they are confluent, meta-confluent, strong normalization preserving, strongly normalizing, simulating, fully compositional, and/or local. In this paper we present a variant of the λσ-calculus......, which satisfies all seven conditions. In particular, we show how to circumvent Mellies counter-example to strong normalization by a slight restriction of the congruence rules. The calculus is implemented as the core data structure of the Celf logical framework. All meta-theoretic aspects of this work...

  13. High-precision measurements of the compressibility of chalcogenide glasses at a hydrostatic pressure up to 9 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Brazhkin, V. V., E-mail: brazhkin@hppi.troitsk.ru [Vereshchagin Institute of High-Pressure Physics (Russian Federation); Bychkov, E. [Universite du Littoral, LPCA, UMR 8101 CNRS (France); Tsiok, O. B. [Vereshchagin Institute of High-Pressure Physics (Russian Federation)

    2016-08-15

    The volumes of glassy germanium chalcogenides GeSe{sub 2}, GeS{sub 2}, Ge{sub 17}Se{sub 83}, and Ge{sub 8}Se{sub 92} are precisely measured at a hydrostatic pressure up to 8.5 GPa. The stoichiometric GeSe{sub 2} and GeS{sub 2} glasses exhibit elastic behavior in the pressure range up to 3 GPa, and their bulk modulus decreases at pressures higher than 2–2.5 GPa. At higher pressures, inelastic relaxation processes begin and their intensity is proportional to the logarithm of time. The relaxation rate for the GeSe{sub 2} glasses has a pronounced maximum at 3.5–4.5 GPa, which indicates the existence of several parallel structural transformation mechanisms. The nonstoichiometric glasses exhibit a diffuse transformation and inelastic behavior at pressures above 1–2 GPa. The maximum relaxation rate in these glasses is significantly lower than that in the stoichiometric GeSe{sub 2} glasses. All glasses are characterized by the “loss of memory” of history: after relaxation at a fixed pressure, the further increase in the pressure returns the volume to the compression curve obtained without a stop for relaxation. After pressure release, the residual densification in the stoichiometric glasses is about 7% and that in the Ge{sub 17}Se{sub 83} glasses is 1.5%. The volume of the Ge{sub 8}Se{sub 92} glass returns to its initial value within the limits of experimental error. As the pressure decreases, the effective bulk moduli of the Ge{sub 17}Se{sub 83} and Ge{sub 8}Se{sub 92} glasses coincide with the moduli after isobaric relaxation at the stage of increasing pressure, and the bulk modulus of the stoichiometric GeSe{sub 2} glass upon decreasing pressure noticeably exceeds the bulk modulus after isobaric relaxation at the stage of increasing pressure. Along with the reported data, our results can be used to draw conclusions regarding the diffuse transformations in glassy germanium chalcogenides during compression.

  14. What Feels Parallel Strongly Depends on Hand Orientation

    NARCIS (Netherlands)

    Kappers, A.M.L.; Liefers, B.J.

    2012-01-01

    Parallel in the outside world is not necessarily perceived as parallel. Previous studies have shown that what is felt as parallel can deviate significantly from what is physically parallel. In a new set-up, the influence of hand/arm orientation is investigated in detail by systematically varying the

  15. Ecosystem respiration depends strongly on photosynthesis in a temperate heath

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, Andreas; Beier, Claus

    2007-01-01

    We measured net ecosystem CO2 flux (F-n) and ecosystem respiration (R-E), and estimated gross ecosystem photosynthesis (P-g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest...... ecosystems with a net ecosystem carbon gain during the second year of 293 +/- 11 g C m(-2) year(-1) showing that the carbon sink strength of heather-dominated ecosystems may be considerable when C. vulgaris is in the building phase of its life cycle. The estimated gross ecosystem photosynthesis and ecosystem.......65) was improved when the P-g rate was incorporated into the model (second year; R-2 = 0.79), suggesting that daytime R-E increased with increasing photosynthesis. Furthermore, the temperature sensitivity of R-E decreased from apparent Q(10) values of 3.3 to 3.9 by the classic equation to a more realistic Q(10...

  16. Ecosystem respiration depends strongly on photosynthesis in a temperate heath

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, A.; Beier, C.

    2007-01-01

    We measured net ecosystem CO2 flux (F-n) and ecosystem respiration (R-E), and estimated gross ecosystem photosynthesis (P-g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest...... respiration from October to March was 22% and 30% of annual flux, respectively, suggesting that both cold-season carbon gain and loss were important in the annual carbon cycle of the ecosystem. Model fit of R-E of a classic, first-order exponential equation related to temperature ( second year; R-2 = 0......) of 2.5 by the modified model. The model introduces R-photo, which describes the part of respiration being tightly coupled to the photosynthetic rate. It makes up 5% of the assimilated carbon dioxide flux at 0 degrees C and 35% at 20 degrees C implying a high sensitivity of respiration to photosynthesis...

  17. The effect of bulk composition on the solidus of carbonated eclogite from partial melting experiments at 3 GPa

    Science.gov (United States)

    Dasgupta, Rajdeep; Hirschmann, Marc M.; Dellas, Nikki

    2005-05-01

    To explore the effect of bulk composition on the solidus of carbonated eclogite, we determined near-solidus phase relations at 3 GPa for four different nominally anhydrous, carbonated eclogites. Starting materials (SLEC1, SLEC2, SLEC3, and SLEC4) were prepared by adding variable proportions and compositions of carbonate to a natural eclogite xenolith (66039B) from Salt Lake crater, Hawaii. Near-solidus partial melts for all bulk compositions are Fe Na calcio-dolomitic and coexist with garnet + clinopyroxene + ilmenite ± calcio-dolomitic solid solution. The solidus for SLEC1 (Ca#=100 × molar Ca/(Ca + Mg + FeT)=32, 1.63 wt% Na2O, and 5 wt% CO2) is bracketed between 1,050°C and 1,075°C (Dasgupta et al. in Earth Planet Sci Lett 227:73 85, 2004), whereas initial melting for SLEC3 (Ca# 41, 1.4 wt% Na2O, and 4.4 wt% CO2) is between 1,175°C and 1,200°C. The solidus for SLEC2 (Ca# 33, 1.75 wt% Na2O, and 15 wt% CO2) is estimated to be near 1,100°C and the solidus for SLEC3 (Ca# 37, 1.47 wt% Na2O, and 2.2 wt% CO2) is between 1,100°C and 1,125°C. Solidus temperatures increase with increasing Ca# of the bulk, owing to the strong influence of the calcite magnesite binary solidus-minimum on the solidus of carbonate bearing eclogite. Bulk compositions that produce near-solidus crystalline carbonate closer in composition to the minimum along the CaCO3-MgCO3 join have lower solidus temperatures. Variations in total CO2 have significant effect on the solidus if CO2 is added as CaCO3, but not if CO2 is added as a complex mixture that maintains the cationic ratios of the bulk-rock. Thus, as partial melting experiments necessarily have more CO2 than that likely to be found in natural carbonated eclogites, care must be taken to assure that the compositional shifts associated with excess CO2 do not unduly influence melting behavior. Near-solidus dolomite and calcite solid solutions have higher Ca/(Ca + Mg) than bulk eclogite compositions, owing to Ca Mg exchange equilibrium

  18. Physics of Strongly Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)

    2007-07-15

    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of 'warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work performed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and

  19. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    during SCES 2010. As we learned, past dogmas about strongly correlated materials and phenomena must be re-examined with an open and inquisitive mind. Invited speakers and respected leaders in the field were invited to contribute to this special issue and we have insisted that they present new data, ideas, or perspectives, as opposed to simply an overview of their past work. As with the conference, this special issue touches upon recent developments of strongly correlated electron systems in d-electron materials, such as Sr3Ru2O7, graphene, and the new Fe-based superconductors, but it is dominated by topics in f-electron compounds. Contributions reflect the growing appreciation for the influence of disorder and frustration, the need for organizing principles, as well as detailed investigations on particular materials of interest and, of course, new materials. As this special issue could not possibly capture the full breadth and depth that the conference had to offer, it is being published simultaneously with an issue of Journal of Physics: Conference Series containing 157 manuscripts in which all poster presenters at SCES 2010 were invited to contribute. Since this special issue grew out of the 2010 SCES conference, we take this opportunity to give thanks. This conference would not have been possible without the hard work of the SCES 2010 Program Committee, International and National Advisory Committees, Local Committee, and conference organizers, the New Mexico Consortium. We thank them as well as those organizations that generously provided financial support: ICAM-I2CAM, Quantum Design, Lakeshore, the National High Magnetic Field Laboratory and the Department of Energy National Laboratories at Argonne, Berkeley, Brookhaven, Los Alamos and Oak Ridge. Of course, we especially thank the participants for bringing new ideas and new results, without which SCES 2010 would not have been possible. Strongly correlated electron systems contents Spin-orbit coupling and k-dependent

  20. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    Different from the early universe, heavy-ion collisions at very high energies do not reach statistical equilibrium, although thermal models explain many of their features. To account for nonequilibrium strong-coupling effects, a Fokker–Planck equation with time-dependent diffusion coefficient is proposed. A schematic model ...

  1. Competition and coexistence of polar and non-polar states in Sr1-x Ca x TiO3: an investigation using pressure dependent Raman spectroscopy

    Science.gov (United States)

    Tyagi, Shekhar; Sharma, Gaurav; Sathe, Vasant G.

    2018-03-01

    The competition and cooperation between ferroelectric and anti-ferro-distortion (AFD) instabilities are studied using pressure dependent Raman spectroscopy on polycrystalline powder samples of Sr1-x Ca x TiO3(x  =  0.0, 0.06, 0.25, 0.35). For x  =  0.0 composition, a broad polar mode is detected in the Raman spectra above 6 GPa, while for x  =  0.06 composition, the polar modes appear well above 9 GPa where the AFD modes showed strong suppression. In x  =  0.25 and 0.35 composition, the application of small pressure resulted in the appearance of strong AFD modes suppressing the polar modes. At elevated pressures, re-entrant polar modes are observed along with the broad AFD modes and some new peaks are also observed, signifying the lowering of local symmetry. The reappearance of polar modes is found to be related to pressure induced symmetry disorder at local level, suggesting its electronic origin. The re-entrant polar modes observed at higher pressure values are found to be significantly broad and asymmetric in nature, signifying the development of ferroelectric micro regions/nano domains coexisting with AFD. The lower symmetry at local length scale provides a conducive atmosphere for coexisting AFD and FE instabilities.

  2. Manometer extension for high pressure measurement: nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa.

    Science.gov (United States)

    Fukazawa, H; Yamatoji, N; Kohori, Y; Terakura, C; Takeshita, N; Tokura, Y; Takagi, H

    2007-01-01

    We report (63)Cu nuclear quadrupole resonance (NQR) measurement of Cu(2)O under pressure up to about 10 GPa at low temperatures. Because the lattice parameter of Cu(2)O changes with increasing pressure, the electric field gradient at the Cu site also changes correspondingly with pressure. This enables us to use the Cu(2)O as an in situ manometer for high pressure nuclear magnetic resonance/NQR up to about 9 GPa.

  3. Measurement of sound velocities of laser-shocked iron at pressures up to 800 GPa

    Science.gov (United States)

    Sakaiya, T.; Takahashi, H.; Kondo, T.; Shigemori, K.; Kadono, T.; Hironaka, Y.; Osaki, N.; Irifune, T.

    2011-12-01

    When we consider the structure of the Earth's interior, the sound velocity is one of the important physical properties of the interior materials because it can be directly compared with the seismological data which can yield the physical properties of the Earth's interior. Although it needs to measure the sound velocity of the interior material under high pressure and temperature, the sound velocity measurement of the materials on the condition over 200 GPa and 4000 K, such as the Earth's core condition, is technically difficult in static compression technique (e.g. diamond anvil cell: DAC) [1-3]. Therefore, in such higher pressure and temperature, dynamic compression technique, such as gas gun, is used. Although some works about the sound velocity of pure iron have been done by gas gun [4-6], it is not enough to discuss about the Earth's core which consists mainly of iron. We performed laser-shock experiments of iron at GEKKO-XII Laser System HIPER irradiation facility in Institute of Laser Engineering, Osaka University (ILE) [7]. The laser-shock compression can generate pressures over 1TPa, which are much higher pressures than previous works by gas gun. The sound velocities of iron were measured by side-on radiography [6]. The laser-irradiated target (Fe) is backlit with an x ray emitted from a high-Z foil (Ti) that is located along the side of the target and that is irradiated by a separate laser. The intensity distribution of the x ray transmitted through the target is imaged onto an x-ray streak camera. When the motion of the front surface and rear surface of the target is obtained from the radiograph, we can obtain the velocity of the shock and rarefaction wave. The rarefaction wave propagates the target with the sound velocity. The pressure generated by the laser-shock compression is obtained from the shock velocity and particle velocity of the target. The particle velocity is obtained from the time revolution of the front surface in the radiograph. In this

  4. Band gap opening in strongly compressed diamond observed by x-ray energy loss spectroscopy

    International Nuclear Information System (INIS)

    Gamboa, E. J.; Fletcher, L. B.; Lee, H. J.; MacDonald, M. J.; Zastrau, U.; Gauthier, M.; Gericke, D. O.; Vorberger, J.; Granados, E.; Hastings, J. B.; Glenzer, S. H.

    2016-01-01

    The extraordinary mechanical and optical properties of diamond are the basis of numerous technical applications and make diamond anvil cells a premier device to explore the high-pressure behavior of materials. However, at applied pressures above a few hundred GPa, optical probing through the anvils becomes difficult because of the pressure-induced changes of the transmission and the excitation of a strong optical emission. Such features have been interpreted as the onset of a closure of the optical gap in diamond, and can significantly impair spectroscopy of the material inside the cell. In contrast, a comparable widening has been predicted for purely hydrostatic compressions, forming a basis for the presumed pressure stiffening of diamond and resilience to the eventual phase change to BC8. We here present the first experimental evidence of this effect at geo-planetary pressures, exceeding the highest ever reported hydrostatic compression of diamond by more than 200 GPa and any other measurement of the band gap by more than 350 GPa. We here apply laser driven-ablation to create a dynamic, high pressure state in a thin, synthetic diamond foil together with frequency-resolved x-ray scattering as a probe. The frequency shift of the inelastically scattered x-rays encodes the optical properties and, thus, the behavior of the band gap in the sample. Using the ultra-bright x-ray beam from the Linac Coherent Light Source (LCLS), we observe an increasing direct band gap in diamond up to a pressure of 370 GPa. This finding points to the enormous strains in the anvils and the impurities in natural Type Ia diamonds as the source of the observed closure of the optical window. Our results demonstrate that diamond remains an insulating solid to pressures approaching its limit strength.

  5. Band gap opening in strongly compressed diamond observed by x-ray energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, E. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fletcher, L. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lee, H. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); MacDonald, M. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States); Zastrau, U. [High-Energy Density Science Group, Hamburg (Germany); Gauthier, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gericke, D. O. [Univ. of Warwick (United Kingdom); Vorberger, J. [Helmholtz Association of German Research Centres, Dresden (Germany); Granados, E. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Glenzer, S. H. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-01-25

    The extraordinary mechanical and optical properties of diamond are the basis of numerous technical applications and make diamond anvil cells a premier device to explore the high-pressure behavior of materials. However, at applied pressures above a few hundred GPa, optical probing through the anvils becomes difficult because of the pressure-induced changes of the transmission and the excitation of a strong optical emission. Such features have been interpreted as the onset of a closure of the optical gap in diamond, and can significantly impair spectroscopy of the material inside the cell. In contrast, a comparable widening has been predicted for purely hydrostatic compressions, forming a basis for the presumed pressure stiffening of diamond and resilience to the eventual phase change to BC8. We here present the first experimental evidence of this effect at geo-planetary pressures, exceeding the highest ever reported hydrostatic compression of diamond by more than 200 GPa and any other measurement of the band gap by more than 350 GPa. We here apply laser driven-ablation to create a dynamic, high pressure state in a thin, synthetic diamond foil together with frequency-resolved x-ray scattering as a probe. The frequency shift of the inelastically scattered x-rays encodes the optical properties and, thus, the behavior of the band gap in the sample. Using the ultra-bright x-ray beam from the Linac Coherent Light Source (LCLS), we observe an increasing direct band gap in diamond up to a pressure of 370 GPa. This finding points to the enormous strains in the anvils and the impurities in natural Type Ia diamonds as the source of the observed closure of the optical window. Our results demonstrate that diamond remains an insulating solid to pressures approaching its limit strength.

  6. Diaplectic quartz glass and SiO2 melt experimentally generated at only 5 GPa shock pressure in porous sandstone: Laboratory observations and meso-scale numerical modeling

    Science.gov (United States)

    Kowitz, A.; Güldemeister, N.; Reimold, W. U.; Schmitt, R. T.; Wünnemann, K.

    2013-12-01

    A combination of shock recovery experiments and numerical modeling of shock deformation in the low pressure range from 2.5 to 17.5 GPa in dry, porous Seeberger sandstone provides new, significant insights with respect to the heterogeneous nature of shock distribution in such important, upper crustal material, for which to date no pressure-calibrated scheme for shock metamorphism exists. We found that pores are already completely closed at 2.5 GPa shock pressure. Whole quartz grains or parts of them are transformed to diaplectic quartz glass and/or SiO2 melt starting already at 5 GPa, whereas these effects are not observed below shock pressures of 30-35 and ˜45 GPa, respectively, in shock experiments with quartz single crystals. The appearance of diaplectic glass or melt is not restricted to the zone directly below the impacted surface but is related to the occurrence of pores in a much broader zone. The combined amount of these phases increases distinctly with increasing shock pressure from 0.03 vol.% at 5 GPa to ˜80 vol.% at 17.5 GPa. In accordance with a previous shock classification for silica phases in naturally shocked Coconino sandstone from Meteor Crater that was based on varied slopes of the Coconino sandstone Hugoniot curve, our observations allow us to construct a shock pressure classification for porous sandstone consistent with shock stages 1b-4 of the progressive shock metamorphism classification of Kieffer (1971).

  7. Phase transition and equation of state of dense hydrous silica up to 63 GPa: DENSE HYDROUS PURE SILICA

    Energy Technology Data Exchange (ETDEWEB)

    Nisr, C. [School of Earth and Space Exploration, Arizona State University, Tempe Arizona USA; Leinenweber, K. [Department of Chemistry and Biochemistry, Arizona State University, Tempe Arizona USA; Prakapenka, V. [Center for Advanced Radiation Sources, University of Chicago, Chicago Illinois USA; Prescher, C. [Center for Advanced Radiation Sources, University of Chicago, Chicago Illinois USA; Now at Institute of Geology and Mineralogy, University of Cologne, Cologne Germany; Tkachev, S. [Center for Advanced Radiation Sources, University of Chicago, Chicago Illinois USA; Shim, S. -H. Dan [School of Earth and Space Exploration, Arizona State University, Tempe Arizona USA

    2017-09-01

    Although it has previously been considered to be essentially anhydrous, Al-free stishovite can contain up to ~1.3 wt % of H2O, perhaps through the direct substitution ( math formula), according to recent studies. Yet the stability of such substitution and its impact on the properties of silica and rutile-structured hydrous phases (such as δ-AlOOH and phase H) are unknown at the conditions of the deeper mantle. We have synthesized hydrous and anhydrous Al-free stishovite samples at 723 K and 9 GPa, and 1473 K and 10 GPa, respectively. Synchrotron X-ray diffraction patterns show that the unit cell volume of hydrous stishovite is 1.3% greater than that of anhydrous stishovite at 1 bar, suggesting significant incorporation of OH in the crystal structure (3.2 ± 0.5 wt % H2O). At 300 K, we found a lower and broader transition pressure from rutile type to CaCl2 type (28–42 GPa) in hydrous dense silica. We also found that hydrous silica polymorphs are more compressible than their anhydrous counterparts. After the phase transition, the unit cell volume of hydrous silica becomes the same as that of anhydrous silica, showing that the proton incorporation through a direct substitution can be further stabilized at high pressure. The lower pressure transition and the pressure stabilization of the proton incorporation in silica would provide ways to transport and store water in the lower mantle in silica-rich heterogeneities, such as subducted oceanic crust.

  8. Aluminosilicate melts and glasses at 1 to 3 GPa: Temperature and pressure effects on recovered structural and density changes

    Science.gov (United States)

    Bista, S; Stebbins, Jonathan; Hankins, William B.; Sisson, Thomas W.

    2015-01-01

    In the pressure range in the Earth’s mantle where many basaltic magmas are generated (1 to 3 GPa) (Stolper et al. 1981), increases in the coordination numbers of the network-forming cations in aluminosilicate melts have generally been considered to be minor, although effects on silicon and particularly on aluminum coordination in non-bridging oxygen-rich glasses from the higher, 5 to 12 GPa range, are now well known. Most high-precision measurements of network cation coordination in such samples have been made by spectroscopy (notably 27Al and 29Si NMR) on glasses quenched from high-temperature, high-pressure melts synthesized in solid-media apparatuses and decompressed to room temperature and 1 bar pressure. There are several effects that could lead to the underestimation of the extent of actual structural (and density) changes in high-pressure/temperature melts from such data. For non-bridging oxygen-rich sodium and calcium aluminosilicate compositions in the 1 to 3 GPa range, we show here that glasses annealed near to their glass transition temperatures systematically record higher recovered increases in aluminum coordination and in density than samples quenched from high-temperature melts. In the piston-cylinder apparatus used, rates of cooling through the glass transition are measured as very similar for both higher and lower initial temperatures, indicating that fictive temperature effects are not the likely explanation of these differences. Instead, transient decreases in melt pressure during thermal quenching, which may be especially large for high initial run temperatures, of as much as 0.5 to 1 GPa, may be responsible. As a result, the equilibrium proportion of high-coordinated Al in this pressure range may be 50 to 90% greater than previously estimated, reaching mean coordination numbers (e.g., 4.5) that are probably high enough to significantly affect melt properties. New data on jadeite (NaAlSi2O6) glass confirm that aluminum coordination increase

  9. Including virtual photons in strong interactions

    International Nuclear Information System (INIS)

    Rusetsky, A.

    2003-01-01

    In the perturbative field-theoretical models we investigate the inclusion of the electromagnetic interactions into the purely strong theory that describes hadronic processes. In particular, we study the convention for splitting electromagnetic and strong interactions and the ambiguity of such a splitting. The issue of the interpretation of the parameters of the low-energy effective field theory in the presence of electromagnetic interactions is addressed, as well as the scale and gauge dependence of the effective theory couplings. We hope, that the results of these studies are relevant for the electromagnetic sector of ChPT. (orig.)

  10. Topics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Skoric, M.M.

    1981-01-01

    This thesis discusses certain aspects of the turbulence of a fully ionised non-isothermal plasma dominated by the Langmuir mode. Some of the basic properties of strongly turbulent plasmas are reviewed. In particular, interest is focused on the state of Langmuir turbulence, that is the turbulence of a simple externally unmagnetized plasma. The problem of the existence and dynamics of Langmuir collapse is discussed, often met as a non-linear stage of the modulational instability in the framework of the Zakharov equations (i.e. simple time-averaged dynamical equations). Possible macroscopic consequences of such dynamical turbulent models are investigated. In order to study highly non-linear collapse dynamics in its advanced stage, a set of generalized Zakharov equations are derived. Going beyond the original approximation, the author includes the effects of higher electron non-linearities and a breakdown of slow-timescale quasi-neutrality. He investigates how these corrections may influence the collapse stabilisation. Recently, it has been realised that the modulational instability in a Langmuir plasma will be accompanied by the collisionless-generation of a slow-timescale magnetic field. Accordingly, a novel physical situation has emerged which is investigated in detail. The stability of monochromatic Langmuir waves in a self-magnetized Langmuir plasma, is discussed, and the existence of a novel magneto-modulational instability shown. The wave collapse dynamics is investigated and a physical interpretation of the basic results is given. A problem of the transient analysis of an interaction of time-dependent electromagnetic pulses with linear cold plasma media is investigated. (Auth.)

  11. Academic procrastination, emotional intelligence, academic self-efficacy, and GPA: a comparison between students with and without learning disabilities.

    Science.gov (United States)

    Hen, Meirav; Goroshit, Marina

    2014-01-01

    Academic procrastination has been seen as an impediment to students' academic success. Research findings suggest that it is related to lower levels of self-regulated learning and academic self-efficacy and associated with higher levels of anxiety, stress, and illness. Emotional intelligence (EI) is the ability to assess, regulate, and utilize emotions and has been found to be associated with academic self-efficacy and a variety of better outcomes, including academic performance. Students with learning disabilities (LD) are well acquainted with academic difficulty and maladaptive academic behavior. In comparison to students without LD, they exhibit high levels of learned helplessness, including diminished persistence, lower academic expectations, and negative affect. This study examined the relationships among academic procrastination, EI, and academic performance as mediated by academic self-efficacy in 287 LD and non-LD students. Results indicated that the indirect effect of EI on academic procrastination and GPA was stronger in LD students than in non-LD students. In addition, results indicated that LD students scored lower than non-LD students on both EI and academic self-efficacy and higher on academic procrastination. No difference was found in GPA.

  12. Electrical conductivity and equation of state of liquid nitrogen, oxygen, benzene, and 1-butene shocked to 60 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, D.C.

    1986-10-08

    Measurements are reported for the electrical conductivity of liquid nitrogen (N/sub 2/), oxygen (O/sub 2/) and benzene (C/sub 6/H/sub 6/), and Hugoniot equation of state of liquid 1-butene (C/sub 4/H/sub 8/) under shock compressed conditions. The conductivity data span 7 x 10/sup -4/ to 7 x 10/sup 1/ ..cap omega../sup -1/cm/sup -1/ over a dynamic pressure range 18.1 to 61.5 GPa and are discussed in terms of amorphous semiconduction models which include such transport phenomena as hopping, percolation, pseudogaps, and metallization. Excellent agreement is found between the equation-of-state measurements, which span a dynamic pressure range 12.3 to 53.8 GPa, and Ree's calculated values which assume a 2-phase mixture consisting of molecular hydrogen and carbon in a dense diamond-like phase. There is a 2-1/2 fold increase in the thermal pressure contribution over a less dense, stoichiometrically equivalent liquid. 90 refs., 48 figs., 8 tabs.

  13. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  14. Strong negative terahertz photoconductivity in photoexcited graphene

    Science.gov (United States)

    Fu, Maixia; Wang, Xinke; Ye, Jiasheng; Feng, Shengfei; Sun, Wenfeng; Han, Peng; Zhang, Yan

    2018-01-01

    Terahertz (THz) response of a chemical vapor deposited graphene on a quartz substrate has been investigated by using an ultrafast optical-pump THz-probe spectroscopy. Without photoexcitation, the frequency-dependence optical conductivity shows a strong carrier response owing to the intrinsically doped graphene. Upon photoexcitation, an enhancement in THz transmission is observed and the transmission increases nonlinearly with the increase of pump power, which is rooted in a reduction of intrinsic conductivity arising from the strong enhancement of carrier scattering rather than THz emission occurrence. The modulation depth of 18.8% was experimentally achieved, which is more than four times greater than that of the previous reported. The photoinduced response here highlights the variety of response possible in graphene depending on the sample quality, carrier mobility and doping level. The graphene provides promising applications in high-performance THz modulators and THz photoelectric devices.

  15. Partial melting of carbonated pelite at 3-7 GPa and deep cycling of CO2 and H2O in subduction zones

    Science.gov (United States)

    Tsuno, K.; Dasgupta, R.; Danielson, L. R.; Righter, K.

    2011-12-01

    The exchange of water and carbon dioxide between the Earth's crustal rocks and the interior is important for understanding geochemical and geophysical evolution of the planet on geologic timescale. Subduction of pelitic sediments is a key mechanism for volatile introduction to the mantle but the high-pressure behavior of H2O+ CO2 bearing sediments is only constrained for alumina-rich, low-Mg# bulk compositions [1, 2]. However, the ocean-floor sediments for many subduction zones that contain both water and CO2 are alumina-poor and have higher Mg#. To constrain the melting behavior of a model alumina poor carbonated pelite, we performed new experiments. Piston cylinder (3 GPa) and multianvil (5 and 7 GPa) experiments were conducted between 800 and 1150 °C, using a model sediment composition containing 1 wt.% H2O and 5 wt.% CO2 (trace vapor-present at subsolidus conditions). The choice of the bulk composition was aimed to model the loss of siliceous hydrous fluid during the shallow part of subduction. We determined the solidus temperatures between 800 and 850 °C at 3 GPa, 900 and 950 °C at 5 GPa, and calcio-carbonatitic, in contrast to the previous experimental results in alumina-rich and low Mg# bulk composition [1, 2], which showed the stability of Al-rich trachyitic silicate melt at near-solidus temperatures up to 5 GPa, and replaced by carbonate melt only at ≥5.5 GPa. Carbonate-silicate melt immiscibility was observed at 5 GPa, 1100 °C in our study. The phengite-out boundary is located between 850 and 900 °C at 3 GPa, between 1000 and 1100 °C at 5 GPa, and calcio-carbonatitic melt, are likely to be released from relatively hot subducting slabs. The observation of carbonate melt inclusion in cpx and garnet in deeply subducted carbonate-rich sediments [3] might be explained by our experimental results that carbonatite is the stable near-solidus sediment melt at deep sub-arc depths. [1] Thomsen, T.B. and Schmidt, M.W. 2008, EPSL 267, 17-31. [2] Grassi, D. and

  16. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R

    1998-12-14

    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  17. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  18. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  19. 学科GPA を利用した学生の学修意欲を把握する指標

    OpenAIRE

    岸上, 明生

    2016-01-01

    GPA(Grade Point Average)制度は,岐阜女子大学に平成24 年度より導入された。健康栄養学科の国試対策室は,専門科目の成績を用いたGPA(学科GPA)を算出し,学科GPA と国家試験結果の相関を検討した結果,累積GPA を学生指導に用いる方法を提案している。厳密な運用が困難な累積GPA は,別の指標で補完することで利用範囲が広がる可能性がある。新しい指標の候補として,学科GPA より近似一次関数の傾き(Slope)を算出し,その特徴を評価した。Slope が学修意欲を反映する可能性が示唆され,累積GPA の利用を補助することが期待される。...

  20. Titanium: light, strong, and white

    Science.gov (United States)

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  1. SAT predicts GPA better for high ability subjects: Implications for Spearman’s Law of Diminishing Returns

    Science.gov (United States)

    Coyle, Thomas; Snyder, Anissa; Pillow, David; Kochunov, Peter

    2011-01-01

    This research examined the predictive validity of the SAT (formerly, the Scholastic Aptitude Test) for high and low ability groups. SAT scores and college GPAs were obtained from the 1997 National Longitudinal Survey of Youth. Subjects were classified as high or low ability by g factor scores from the Armed Services Vocational Aptitude Battery. SAT correlations with GPA were higher for high than low ability subjects. SAT g loadings (i.e., SAT correlations with g) were equivalent for both groups. This is the first study to show that the predictive validity of the SAT varies for ability groups that differ in g. The results contradict a presumption, based on Spearman’s Law of Diminishing Returns, that a test’s predictive validity should be lower for high ability subjects. Further research is needed to identify factors that contribute to the predictive validity of the SAT for groups that differ in g. PMID:21562615

  2. The equation of state of PbTiO sub 3 up to 37 GPa: a synchrotron x-ray powder diffraction study

    CERN Document Server

    Sani, A; Levy, D

    2002-01-01

    High-pressure synchrotron x-ray powder diffraction patterns were collected using ID09 of ESRF (Grenoble, France) for a powder sample of PbTiO sub 3 , placed in a diamond anvil cell. The patterns were collected at room temperature using nitrogen (up to 37 GPa) and methanol-ethanol solution (up to 7 GPa) as pressure-transmitting media. The bulk moduli were calculated for the first time using the Vinet equation of state and they were compared to those of isostructural compounds. The trend of the spontaneous polarization as a function of pressure confirms that the ferroelectric-paraelectric phase transition at 11.2 GPa possesses a second-order character.

  3. The criterion-related validity of personality measures for predicting GPA: a meta-analytic validity competition.

    Science.gov (United States)

    McAbee, Samuel T; Oswald, Frederick L

    2013-06-01

    Interest in the role of personality traits in predicting academic performance outcomes has steadily increased over the last several decades, enough to produce a number of meta-analyses that summarize this research (e.g., Poropat, 2009; Richardson, Abraham, & Bond, 2012). These previous meta-analyses combine a variety of alternative personality measures under the assumption that they all reflect the same personality traits and thus predict outcomes similarly. The current meta-analysis tests this assumption by comparing different personality measures when predicting postsecondary grade point average (GPA). The operational validities (r+) of 5 frequently used measures of the Big Five personality traits were compared: the NEO Personality Inventory--Revised (NEO-PI-R; Costa & McCrae, 1992), the NEO Five-Factor Inventory (NEO-FFI; Costa & McCrae, 1992), the Big Five Inventory (BFI; e.g., Benet-Martínez & John, 1998), Goldberg's (1992) unipolar Big Five Factor Markers (Markers), and the Big Five International Personality Item Pool (IPIP; Goldberg, 1999). A systematic review of the psychological literature from 1992 to 2012 was conducted, identifying 51 studies containing 274 correlations. Conscientiousness demonstrated the strongest criterion-related validity for predicting GPA (r+ = .23), consistent with previous meta-analyses; in addition, this overall validity was found to be robust across measures (r(BFI)(+) = .24, r(IPIP)(+) = .21, r(Markers)(+) = .15, r(NEO-FFI)(+) = .24, r(NEO-PI-R)(+) = .26). Although the criterion-related validities for Extraversion, Agreeableness, Neuroticism, and Openness to Experience (Intellect) differed by measure, they were generally low (r+s < .10). Practical implications of the findings and directions for future research are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  4. Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 GPa and 1073 K: Tracking Silica in Earth's Upper Mantle

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ting [Department of Geosciences, Stony Brook University, Stony Brook New York USA; Liebermann, Robert C. [Department of Geosciences, Stony Brook University, Stony Brook New York USA; Mineral Physics Institute, Stony Brook University, Stony Brook New York USA; Zou, Yongtao [Mineral Physics Institute, Stony Brook University, Stony Brook New York USA; State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun China; Li, Ying [Mineral Physics Institute, Stony Brook University, Stony Brook New York USA; Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, China Earthquake Administration, Beijing China; Qi, Xintong [Department of Geosciences, Stony Brook University, Stony Brook New York USA; Li, Baosheng [Department of Geosciences, Stony Brook University, Stony Brook New York USA; Mineral Physics Institute, Stony Brook University, Stony Brook New York USA

    2017-08-12

    The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 GPa and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach ~34% and ~45% for P and S wave velocities, respectively, and ~64% and ~75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences on silica, d(lnVP)/d(SiO2) = 0.38 (wt %)-1 and d(lnVS)/d(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.

  5. Making (up) the grade? estimating the genetic and environmental influences of discrepancies between self-reported grades and official GPA scores.

    Science.gov (United States)

    Schwartz, Joseph A; Beaver, Kevin M

    2015-05-01

    Academic achievement has been found to have a pervasive and substantial impact on a wide range of developmental outcomes and has also been implicated in the critical transition from adolescence into early adulthood. Previous research has revealed that self-reported grades tend to diverge from official transcript grade point average (GPA) scores, with students being more likely to report inflated scores. Making use of a sample of monozygotic twin (N = 282 pairs), dizygotic twin (N = 441 pairs), and full sibling (N = 1,757 pairs) pairs from the National Longitudinal Study of Adolescent Health (Add Health; 65 % White; 50 % male; mean age = 16.14), the current study is the first to investigate the role that genetic and environmental factors play in misreporting grade information. A comparison between self-reported GPA (mean score of 2.86) and official transcript GPA scores (mean score of 2.44) revealed that self-reported scores were approximately one-half letter grade greater than official scores. Liability threshold models revealed that additive genetic influences explained between 40 and 63 % of the variance in reporting inflated grades and correctly reporting GPA, with the remaining variance explained by the nonshared environment. Conversely, 100 % of the variance in reporting deflated grade information was explained by nonshared environmental influences. In an effort to identify specific nonshared environmental influences on reporting accuracy, multivariate models that adequately control for genetic influences were estimated and revealed that siblings with lower transcript GPA scores were significantly less likely to correctly report their GPA and significantly more likely to report inflated GPA scores. Additional analyses revealed that verbal IQ and self-control were not significantly associated with self-reported GPA accuracy after controlling for genetic influences. These findings indicate that previous studies that implicate verbal IQ and self

  6. Stokes-Einstein relation in liquid iron-nickel alloy up to 300 GPa

    Science.gov (United States)

    Cao, Q.-L.; Wang, P.-P.

    2017-05-01

    Molecular dynamic simulations were applied to investigate the Stokes-Einstein relation (SER) and the Rosenfeld entropy scaling law (ESL) in liquid Fe0.9Ni0.1 over a sufficiently broad range of temperatures (0.70 ESL hold well in the normal liquid region and break down in the supercooled region under high-pressure conditions, and the deviation becomes larger with decreasing temperature. In other words, the SER can be used to calculate the viscosity of liquid Earth's outer core from the self-diffusion coefficients of iron/nickel and the ESL can be used to predict the viscosity and diffusion coefficients of liquid Earth's outer core form its structural properties. In addition, the pressure dependence of effective diameters cannot be ignored in the course of using the SER. Moreover, ESL provides a useful, structure-based probe for the validity of SER, while the ratio of the self-diffusion coefficients of the components cannot be used as a probe for the validity of SER.

  7. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  8. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  9. Towards TDDFT for Strongly Correlated Materials

    Directory of Open Access Journals (Sweden)

    Shree Ram Acharya

    2016-09-01

    Full Text Available We present some details of our recently-proposed Time-Dependent Density-Functional Theory (TDDFT for strongly-correlated materials in which the exchange-correlation (XC kernel is derived from the charge susceptibility obtained using Dynamical Mean-Field Theory (the TDDFT + DMFT approach. We proceed with deriving the expression for the XC kernel for the one-band Hubbard model by solving DMFT equations via two approaches, the Hirsch–Fye Quantum Monte Carlo (HF-QMC and an approximate low-cost perturbation theory approach, and demonstrate that the latter gives results that are comparable to the exact HF-QMC solution. Furthermore, through a variety of applications, we propose a simple analytical formula for the XC kernel. Additionally, we use the exact and approximate kernels to examine the nonhomogeneous ultrafast response of two systems: a one-band Hubbard model and a Mott insulator YTiO3. We show that the frequency dependence of the kernel, i.e., memory effects, is important for dynamics at the femtosecond timescale. We also conclude that strong correlations lead to the presence of beats in the time-dependent electric conductivity in YTiO3, a feature that could be tested experimentally and that could help validate the few approximations used in our formulation. We conclude by proposing an algorithm for the generalization of the theory to non-linear response.

  10. Vehicle technologies program Government Performance and Results Act (GPA) report for fiscal year 2012

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.; Stephens, T. S.; Birky, A. K. (Energy Systems); (DOE-EERE); (TA Engineering)

    2012-08-10

    The U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy has defined milestones for its Vehicle Technologies Program (VTP). This report provides estimates of the benefits that would accrue from achieving these milestones relative to a base case that represents a future in which there is no VTP-supported vehicle technology development. Improvements in the fuel economy and reductions in the cost of light- and heavy-duty vehicles were estimated by using Argonne National Laboratory's Autonomie powertrain simulation software and doing some additional analysis. Argonne also estimated the fraction of the fuel economy improvements that were attributable to VTP-supported development in four 'subsystem' technology areas: batteries and electric drives, advanced combustion engines, fuels and lubricants, and materials (i.e., reducing vehicle mass, called 'lightweighting'). Oak Ridge National Laboratory's MA{sup 3}T (Market Acceptance of Advanced Automotive Technologies) tool was used to project the market penetration of light-duty vehicles, and TA Engineering's TRUCK tool was used to project the penetrations of medium- and heavy-duty trucks. Argonne's VISION transportation energy accounting model was used to estimate total fuel savings, reductions in primary energy consumption, and reductions in greenhouse gas emissions that would result from achieving VTP milestones. These projections indicate that by 2030, the on-road fuel economy of both light- and heavy-duty vehicles would improve by more than 20%, and that this positive impact would be accompanied by a reduction in oil consumption of nearly 2 million barrels per day and a reduction in greenhouse gas emissions of more than 300 million metric tons of CO{sub 2} equivalent per year. These benefits would have a significant economic value in the U.S. transportation sector and reduce its dependency on oil and its vulnerability to oil price shocks.

  11. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies......, but it is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing - time...

  12. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  13. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  14. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  15. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  16. Electron-hole balance and the anomalous pressure-dependent superconductivity in black phosphorus

    Science.gov (United States)

    Guo, Jing; Wang, Honghong; von Rohr, Fabian; Yi, Wei; Zhou, Yazhou; Wang, Zhe; Cai, Shu; Zhang, Shan; Li, Xiaodong; Li, Yanchun; Liu, Jing; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Xiang, Tao; Cava, Robert J.; Sun, Liling

    2017-12-01

    Here we report the in situ high-pressure (up to ˜50 -GPa) Hall-effect measurements on single-crystal black phosphorus. We find a strong correlation between the sign of the Hall coefficient, an indicator of the dominant carrier type, and the superconducting transition temperature (TC). Importantly, we find a change from electron-dominant to hole-dominant carriers in the simple cubic phase of phosphorus at a pressure of ˜17.2 GPa, providing an explanation for the puzzling valley it displays in its superconducting TC vs pressure phase diagram. Our results reveal that hole carriers play an important role in developing superconductivity in elemental phosphorus and the valley in TC at 18.8 GPa is associated with a Lifshitz transition.

  17. Stimulated Superconductivity at Strong Coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Ning; Dong, Xi; Silverstein, Eva; Torroba, Gonzalo; /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC

    2011-08-12

    Stimulating a system with time dependent sources can enhance instabilities, thus increasing the critical temperature at which the system transitions to interesting low-temperature phases such as superconductivity or superfluidity. After reviewing this phenomenon in non-equilibrium BCS theory (and its marginal fermi liquid generalization) we analyze the effect in holographic superconductors. We exhibit a simple regime in which the transition temperature increases parametrically as we increase the frequency of the time-dependent source.

  18. Novel 1.5 GPa-strength with 50%-ductility by transformation-induced plasticity of non-recrystallized austenite in duplex steels.

    Science.gov (United States)

    Sohn, Seok Su; Song, Hyejin; Jo, Min Chul; Song, Taejin; Kim, Hyoung Seop; Lee, Sunghak

    2017-04-28

    Needs for steel designs of ultra-high strength and excellent ductility have been an important issue in worldwide automotive industries to achieve energy conservation, improvement of safety, and crashworthiness qualities. Because of various drawbacks in existing 1.5-GPa-grade steels, new development of formable cold-rolled ultra-high-strength steels is essentially needed. Here we show a plausible method to achieve ultra-high strengths of 1.0~1.5 GPa together with excellent ductility above 50% by actively utilizing non-recrystallization region and TRansformation-Induced Plasticity (TRIP) mechanism in a cold-rolled and annealed Fe-Mn-Al-C-based steel. We adopt a duplex microstructure composed of austenite and ultra-fine ferrite in order to overcome low-yield-strength characteristics of austenite. Persistent elongation up to 50% as well as ultra-high yield strength over 1.4 GPa are attributed to well-balanced mechanical stability of non-crystallized austenite with critical strain for TRIP. Our results demonstrate how the non-recrystallized austenite can be a metamorphosis in 1.5-GPa-grade steel sheet design.

  19. High-pressure structural study of fluoro-perovskite CsCdF3 up to 60 GPa: A combined experimental and theoretical study

    DEFF Research Database (Denmark)

    Vaitheeswaran, G.; Kanchana, V.; Kumar, Ravhi S.

    2010-01-01

    The structural behavior of CsCdF3 under pressure is investigated by means of theory and experiment. High-pressure powder x-ray diffraction experiments were performed up to a maximum pressure of 60 GPa using synchrotron radiation. The cubic Pm3̅ m crystal symmetry persists throughout this pressure...

  20. 40 CFR 80.595 - How does a small or GPA refiner apply for a motor vehicle diesel fuel volume baseline for the...

    Science.gov (United States)

    2010-07-01

    ... for a motor vehicle diesel fuel volume baseline for the purpose of extending their gasoline sulfur... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive... a small or GPA refiner apply for a motor vehicle diesel fuel volume baseline for the purpose of...

  1. The Impact of Four-Year Participation in Music and/or Athletic Activities in South Dakota Public High Schools on GPA and ACT Scores

    Science.gov (United States)

    Jones, Patrick S.

    2010-01-01

    Finding the key to success for high school students has long been the goal for both school personnel and parents. This study examined the impact of four-year participation in music and/or athletics activities in South Dakota public high schools on student GPA and ACT scores. The data in this study were collected from five Class A high schools…

  2. Impact of Delivery Modality, Student GPA, and Time-Lapse since High School on Successful Completion of College-Level Math after Taking Developmental Math

    Science.gov (United States)

    Acosta, Diane; North, Teresa Lynn; Avella, John

    2016-01-01

    This study considered whether delivery modality, student GPA, or time since high school affected whether 290 students who had completed a developmental math series as a community college were able to successfully complete college-level math. The data used in the study was comprised of a 4-year period historical student data from Odessa College…

  3. Experimental Thermodynamics of [Na-Mg-Cl-SO4] Aqueous Solutions at GPa Pressure With Application to Icy Worlds.

    Science.gov (United States)

    Brown, J. M.; Bollengier, O.; Vance, S.

    2017-12-01

    Water competes with silicates as the main constituent of solid bodies in the outer solar system. Ganymede and Titan, the Mercury-sized satellites of Jupiter and Saturn, are made up half of water present as massive hydrospheres where pressure can reach up to 1.5 GPa. Geophysical data and planetary models unequivocally support the existence of global aqueous oceans trapped in these hydrospheres. However, the extent of these oceans and their role in the processes governing the internal structure of these moons remain unresolved. At issue is the poor to non-existent characterization, at the relevant pressures, of the properties of the aqueous fluids of significance to the outer solar system (with notably the Na-Mg-Cl-SO4 salts found in primitive chondrites), forcing current models to rely on pure water only. Our team at the University of Washington has developed an experimental apparatus to acquire the speed of sound of aqueous solutions in the 0 - 0.7 GPa and 250 - 350 K pressure and temperature ranges covering most of the conditions of existence of these extra-terrestrial oceans. Speeds of sound measured over a grid of pressures and temperatures allow calculation of the thermodynamic quantities (G, ρ, μ...) required for planetary science. Early analysis of pure water samples indicates our experimental results are on par with (at lower pressures), or better than, the IAPWS water laboratory standard, with sound speeds determined to 0.02% over our entire pressure range. For the first time at the high pressures of interest for large icy moons, we achieved the exploration of H2O-NaCl, H2O-MgSO4, H2O-Na2SO4 and H2O-MgCl2 solutions, from dilute concentrations to saturation. We are now in the process of acquiring the first data for H2O-NaCl-MgSO4 mixtures. We will briefly present our experimental setup and the underlying sound speed theory, and will then compare our results for the four endmembers, with an emphasis on their different association behavior under pressure as

  4. Bio-inspired multiproperty materials: strong, self-healing, and transparent artificial wood nanostructures.

    Science.gov (United States)

    Merindol, Rémi; Diabang, Seydina; Felix, Olivier; Roland, Thierry; Gauthier, Christian; Decher, Gero

    2015-02-24

    Nanocomposite films possessing multiple interesting properties (mechanical strength, optical transparency, self-healing, and partial biodegradability) are discussed. We used Layer-by-Layer assembly to prepare micron thick wood-inspired films from anionic nanofibrillated cellulose and cationic poly(vinyl amine). The film growth was carried out at different pH values to obtain films of different chemical composition, whereby, and as expected, higher pH values led to a higher polycation content and also to 6 times higher film growth increments (from 9 to 55 nm per layer pair). In the pH range from 8 to 11, micron thick and optically transparent LbL films are obtained by automated dipping when dried regularly in a stream of air. Films with a size of 10 cm(2) or more can be peeled from flat surfaces; they show tensile strengths up to about 250 MPa and Young's moduli up to about 18 GPa as controlled by the polycation/polyanion ratio of the film. Experiments at different humidities revealed the plasticizing effect of water in the films and allowed reversible switching of their mechanical properties. Whereas dry films are strong and brittle (Young's modulus: 16 GPa, strain at break: 1.7%), wet films are soft and ductile (Young's modulus: 0.1 GPa, strain at break: 49%). Wet film surfaces even amalgamate upon contact to yield mechanically stable junctions. We attribute the switchability of the mechanical properties and the propensity for self-repair to changes in the polycation mobility that are brought about by the plastifying effect of water.

  5. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...... plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning....... The sample size in transition is relatively large and easily accessible in experiments, making our understanding of size dependence11, 12, 13, 14, 15, 16, 17 relevant for applications....

  6. Enhanced thermal photon and dilepton production in strongly coupled = 4 SYM plasma in strong magnetic field

    Science.gov (United States)

    Mamo, Kiminad A.

    2013-08-01

    We calculate the DC conductivity tensor of strongly coupled = 4 super-Yang-Mills (SYM) plasma in a presence of a strong external magnetic field B ≫ T 2 by using its gravity dual and employing both the RG flow approach and membrane paradigm which give the same results. We find that, since the magnetic field B induces anisotropy in the plasma, different components of the DC conductivity tensor have different magnitudes depending on whether its components are in the direction of the magnetic field B. In particular, we find that a component of the DC conductivity tensor in the direction of the magnetic field B increases linearly with B while the other components (which are not in the direction of the magnetic field B) are independent of it. These results are consistent with the lattice computations of the DC conductivity tensor of the QCD plasma in an external magnetic field B. Using the DC conductivity tensor, we calculate the soft or low-frequency thermal photon and dilepton production rates of the strongly coupled = 4 SYM plasma in the presence of the strong external magnetic field B ≫ T 2. We find that the strong magnetic field B enhances both the thermal photon and dilepton production rates of the strongly coupled = 4 SYM plasma in a qualitative agreement with the experimentally observed enhancements at the heavy-ion collision experiments.

  7. Flow curves of hcp-iron up to 19 GPa and 600 K using a combination of synchrotron radiation and the DDIA

    Science.gov (United States)

    Nishiyama, N.; Wang, Y.; Rivers, M. L.; Sutton, S. R.; Cookson, D.

    2006-12-01

    We performed in-situ X-ray diffraction and radiography experiments of hcp-iron up to 19 GPa and 600 K. Deformation experiments were performed at the GSECARS 13-BM-D beamline (APS) using a DDIA with a monochromatic X-ray diffraction and a radiographic imaging system. We used four tungsten carbide and two sintered diamond anvils with truncated edge length of 2 mm. Pressure medium was a mixture of boron and epoxy and a cylindrical graphite furnace was used. The starting material was a fragment of pure bcc-iron wire and two deformation pistons made of alumina were situated above and below the sample. First, the cell assembly was compressed uniformly at room temperature up to about 14 GPa. Then the sample was heated to about 700 K to convert bcc to hcp-iron. After the transformation, several deformation cycles were carried out, yielding five independent stress-strain curves with sample shortening at pressures up to 19 GPa and three different temperatures (600, 400, and 300 K). In all the curves, differential stresses reached saturation at about 3 percent strain, suggesting that deformation reached steady state. The differential stresses at steady state flow were 1.8-2.5 GPa, decreasing with increasing temperature and decreasing strain rate. Using isothermal mechanical data, we determined stress exponents (n) at 600 and 400 K, yielding 7 and 31, respectively. The mechanical data of hcp-iron are consistent with the deformation mechanism map of zinc (Ashby and Frost, 1981), which suggests that, at about 18 GPa, hcp-iron deforms in the Peierls plasticity (low-temperature plasticity) regime at 400 K whereas it deforms in the low-temperature power-law creep regime at 600 K. Thus, deformation mechanisms map of hcp-iron may be similar to those of other hexagonal metals, such as zinc.

  8. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  9. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  10. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  11. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  12. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  13. Shock recovery experiments in the range of 10 to 45 GPa - comparison of results of synthetic magnetite and terrestrial diabase

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Pesonen, L.; Deutsch, A.; Honnermann, U.

    89 /53/, Fall Meeting Supplement (2008), , GP21C-0790-GP21C-0790 ISSN 0096-3941. [American Geophysical Union Fall Meeting. 15.12.2008-19.12.2008, San Francisco] Institutional research plan: CEZ:AV0Z30130516 Keywords : shock experiments * magnetite * diabase Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm08&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=kohout&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c766%7c5433%7cShock%20recovery%20experiments%20in%20the%20range%20of%2010%20to%2045%20GPa%20-%20comparison%20of%20results%20of%20synthetic%20magnetite%20and%20terrestrial%20diabase%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c19257669%2019263102%20%2fdata2%2fepubs%2fwais%2fdata%2ffm08%2ffm08.txt

  14. Accurate Hugoniots and sound velocities of bismuth under shock compression in the 38-100 GPa range

    Directory of Open Access Journals (Sweden)

    Feng Xi

    2018-01-01

    Full Text Available Dynamic compression experiments of bismuth (Bi in a shock pressure range of 38-100 GPa were conducted using an explosive drive. The time-resolved particle velocity profiles at the Bi/LiF (lithium fluoride interface and the impact velocities were recorded with a displacement interferometer system for any reflector (DISAR. Shock velocities of Bi were measured based on the shorted-pin technique. Sound velocities of Bi were obtained from the peak state time duration measurements with the overtake method. Uncertainties in the measured Hugoniots and sound velocities were analyzed carefully. The new Hugoniot relation, Us = (1.666 ± 0.057 km/s + (1.596 ± 0.037Up (1.13 km/s ≤Up≤2.05 km/s, was determined by fitting the measured shock velocity and particle velocity to a line. The relation between the Grüneisen coefficient and the density, γρ=const., is found to be a good approximation to describe the sound velocities of Bi above the shock-induced melting pressure, by carefully analysis of the sound velocity data.

  15. From Wade-Mingos to Zintl-Klemm at 100 GPa: binary compounds of boron and lithium.

    Science.gov (United States)

    Hermann, Andreas; McSorley, Alexandra; Ashcroft, N W; Hoffmann, Roald

    2012-11-14

    Structural diversity and a variety of bonding schemes emerge as characteristics of the Li-B phase diagram in this ground-state theoretical investigation. We studied stoichiometries ranging from LiB(15) to Li(5)B, over a pressure range from 1 atm to 300 GPa. At P = 1 atm, stability is found for the experimentally known LiB(0.8-1.0), LiB(3), and Li(3)B(14) phases. As the pressure rises, the latter two structures are no longer even metastable, while the LiB(0.8-1.0) structures change in geometry and narrow their range of off-stoichiometry, eventually coming at high pressure to a diamondoid NaTl-type LiB. This phase then dominates the convex hull of stability. Other phases emerge as stable points at some pressure: LiB(4), Li(3)B(2), Li(2)B, and Li(5)B. At the boron-rich end, one obtains structures expectedly containing polyhedral motifs, and geometries are governed by Wade-Mingos electron counts; LiB(4) has a BaAl(4) structure. In the center and on the lithium-rich side of the phase diagram, Zintl-phase considerations, i.e., bonding between B(n-) entities, give us insight into the structures-tetrahedral B(-) networks in LiB; B pairs to isolated bonds in Li(5)B.

  16. Response of the polymers KEL-F, polysulfone, high density polyethylene and polymethylmethacrylate to shock loading and release from 0. 3 to 2. 4 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, M.U.

    1991-01-01

    The Bauer PVDF stress-rate gauge has been used to study the response of the cited polymers from measurements at the impact surface and in-situ'' at sample thicknesses of 1.5 and 3 mm. The PVDF stress- rate dependent piezoelectric output combined with appropriate signal recording techniques allow accurate recording over the broad range of stress rates encountered during shock compression of polymers. Strong viscous response effects are observed. The release velocity is found to increase strongly with pressure, and the release-rate history is recorded with PVDF as a continuous function of pressure. 12 refs., 4 figs., 1 tab.

  17. Strongly Interacting Light Dark Matter

    Directory of Open Access Journals (Sweden)

    Sebastian Bruggisser, Francesco Riva, Alfredo Urbano

    2017-09-01

    Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.

  18. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  19. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  20. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  1. Strong Plate, Weak Slab Dichotomy

    Science.gov (United States)

    Petersen, R. I.; Stegman, D. R.; Tackley, P.

    2015-12-01

    Models of mantle convection on Earth produce styles of convection that are not observed on Earth.Moreover non-Earth-like modes, such as two-sided downwellings, are the de facto mode of convection in such models.To recreate Earth style subduction, i.e. one-sided asymmetric recycling of the lithosphere, proper treatment of the plates and plate interface are required. Previous work has identified several model features that promote subduction. A free surface or pseudo-free surface and a layer of material with a relatively low strength material (weak crust) allow downgoing plates to bend and slide past overriding without creating undue stress at the plate interface. (Crameri, et al. 2012, GRL)A low viscosity mantle wedge, possibly a result of slab dehydration, decouples the plates in the system. (Gerya et al. 2007, Geo)Plates must be composed of material which, in the case of the overriding plate, are is strong enough to resist bending stresses imposed by the subducting plate and yet, as in the case of the subducting plate, be weak enough to bend and subduct when pulled by the already subducted slab. (Petersen et al. 2015, PEPI) Though strong surface plates are required for subduction such plates may present a problem when they encounter the lower mantle.As the subducting slab approaches the higher viscosity, lower mantle stresses are imposed on the tip.Strong slabs transmit this stress to the surface.There the stress field at the plate interface is modified and potentially modifies the style of convection. In addition to modifying the stress at the plate interface, the strength of the slab affects the morphology of the slab at the base of the upper mantle. (Stegman, et al 2010, Tectonophysics)Slabs that maintain a sufficient portion of their strength after being bent require high stresses to unbend or otherwise change their shape.On the other hand slabs that are weakened though the bending process are more amenable to changes in morphology. We present the results of

  2. Strong interaction studies with kaonic atoms

    Directory of Open Access Journals (Sweden)

    Marton J.

    2016-01-01

    Full Text Available The strong interaction of antikaons (K− with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K−pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAΦNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K−p atom leading to a hadronic shift ϵ1s and a hadronic broadening Γ1s of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated constrained by the SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent scattering lengths a measurement of the hadronic shift and width of kaonic deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. Many improvements in the experimental setup will allow to measure kaonic deuterium which is challenging due to the anticipated low X-ray yield. Especially important are the data on the X-ray yields of kaonic deuterium extracted from a exploratory experiment within SIDDHARTA.

  3. Electromotive force in strongly compressible magnetohydrodynamic turbulence

    Science.gov (United States)

    Yokoi, N.

    2017-12-01

    Variable density fluid turbulence is ubiquitous in geo-fluids, not to mention in astrophysics. Depending on the source of density variation, variable density fluid turbulence may be divided into two categories: the weak compressible (entropy mode) turbulence for slow flow and the strong compressible (acoustic mode) turbulence for fast flow. In the strong compressible turbulence, the pressure fluctuation induces a strong density fluctuation ρ ', which is represented by the density variance ( denotes the ensemble average). The turbulent effect on the large-scale magnetic-field B induction is represented by the turbulent electromotive force (EMF) (u': velocity fluctuation, b': magnetic-field fluctuation). In the usual treatment in the dynamo theory, the expression for the EMF has been obtained in the framework of incompressible or weak compressible turbulence, where only the variation of the mean density , if any, is taken into account. We see from the equation of the density fluctuation ρ', the density variance is generated by the large mean density variation ∂ coupled with the turbulent mass flux . This means that in the region where the mean density steeply changes, the density variance effect becomes relevant for the magnetic field evolution. This situation is typically the case for phenomena associated with shocks and compositional discontinuities. With the aid of the analytical theory of inhomogeneous compressible magnetohydrodynamic (MHD) turbulence, the expression for the turbulent electromotive force is investigated. It is shown that, among others, an obliqueness (misalignment) between the mean density gradient ∂ and the mean magnetic field B may contribute to the EMF as ≈χ B×∂ with the turbulent transport coefficient χ proportional to the density variance (χ ). This density variance effect is expected to strongly affect the EMF near the interface, and changes the transport properties of turbulence. In the case of an interface under the MHD slow

  4. Prediction of Osteopathic Medical School Performance on the basis of MCAT score, GPA, sex, undergraduate major, and undergraduate institution.

    Science.gov (United States)

    Dixon, Donna

    2012-04-01

    The relationships of students' preadmission academic variables, sex, undergraduate major, and undergraduate institution to academic performance in medical school have not been thoroughly examined. To determine the ability of students' preadmission academic variables to predict osteopathic medical school performance and whether students' sex, undergraduate major, or undergraduate institution influence osteopathic medical school performance. The study followed students who graduated from New York College of Osteopathic Medicine of New York Institute of Technology in Old Westbury between 2003 and 2006. Student preadmission data were Medical College Admission Test (MCAT) scores, undergraduate grade point averages (GPAs), sex, undergraduate major, and undergraduate institutional selectivity. Medical school performance variables were GPAs, clinical performance (ie, clinical subject examinations and clerkship evaluations), and scores on the Comprehensive Osteopathic Medical Licensing Examination-USA (COMLEX-USA) Level 1 and Level 2-Clinical Evaluation (CE). Data were analyzed with Pearson product moment correlation coefficients and multivariate linear regression analyses. Differences between student groups were compared with the independent-samples, 2-tailed t test. A total of 737 students were included. All preadmission academic variables, except nonscience undergraduate GPA, were statistically significant predictors of performance on COMLEX-USA Level 1, and all preadmission academic variables were statistically significant predictors of performance on COMLEX-USA Level 2-CE. The MCAT score for biological sciences had the highest correlation among all variables with COMLEX-USA Level 1 performance (Pearson r=0.304; Posteopathic medical school performance, including GPAs, clinical performance, and COMLEX-USA Level 1 and Level 2-CE results. Clinical performance was predictive of COMLEX-USA Level 2-CE performance.

  5. Strongly coupled dust coulomb clusters

    International Nuclear Information System (INIS)

    Juan Wentau; Lai Yingju; Chen Mingheng; I Lin

    1999-01-01

    The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing

  6. Probability densities in strong turbulence

    Science.gov (United States)

    Yakhot, Victor

    2006-03-01

    In this work we, using Mellin’s transform combined with the Gaussian large-scale boundary condition, calculate probability densities (PDFs) of velocity increments P(δu,r), velocity derivatives P(u,r) and the PDF of the fluctuating dissipation scales Q(η,Re), where Re is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF P(δu,r) often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for the deviation of P(δu,r) from P(δu,r). An expression for the function D(h) of the multifractal theory, free from spurious logarithms recently discussed in [U. Frisch, M. Martins Afonso, A. Mazzino, V. Yakhot, J. Fluid Mech. 542 (2005) 97] is also obtained.

  7. Elasticity moduli dependences on the magnetic field of Fe73.5Cu1Nb3Si13.5B9 strips annealed in the range from 300 to 600 C

    International Nuclear Information System (INIS)

    Kaczkowski, Z.; Vlasak, G.; Duhaj, P.

    1996-01-01

    The magnetic field dependences of the elasticity moduli of Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 strips annealed in vacuum for 1 h at 300-600 C were investigated. The maximum changes (ΔE effect), from 60 to 170 GPa, were observed after annealing at 450 C. After annealing at 550 C these changes were from 180 to 210 GPa. The changes are associated with magnetomechanical coupling. (orig.)

  8. Material properties of Ni-Cr-Al alloy and design of a 4 GPa class non-magnetic high-pressure cell

    CERN Document Server

    Uwatoko, Y; Ueda, K; Uchida, A; Kosaka, M; Mori, N; Matsumoto, T

    2002-01-01

    The Ni-Cr-Al Russian alloy was prepared. Its magnetic and mechanical properties were better than those of MP35N alloy. We fabricated the a piston-cylinder-type hybrid high-pressure cell using the Ni-Cr-Al alloy. It has been found that the maximum working pressure can be repeatedly raised to 3.5 GPa at T = 2 K without any difficulties.

  9. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown......One of the most intriguing recent results in physics is the growing evidence that an unknown energy field and an unknown kind of matter are the major components of the Universe (70% and 30%, respectively; see e.g. Riess et al. 1998, Spergel et al. 2007). Understanding and estimating the precise...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies...

  10. Gas gun experiments and numerical simulations on the HMX-based explosive PBX 9501 in the overdriven 30 to 120 GPa pressure regime

    Science.gov (United States)

    Pittman, E. R.; Gustavsen, R. L.; Hagelberg, C. R.; Schmidt, J. H.

    2017-06-01

    The focus of this set of experiments is the development of data on the Hugoniot for the overdriven products equation of state (EOS) of PBX 9501 (95 weight % HMX, 5 weight % plastic binder) and to extend data from which current computational EOS models draw. This series of shots was conducted using the two-stage gas-guns at Los Alamos and aimed to gather data in the 30 to 120 GPa pressure regime. Experiments were simulated using FLAG, a Langrangian multiphysics code, using a one-dimensional setup which employs the Wescott Stewart Davis (WSD) reactive burn model. Prior to this study, data did not extend above 90 GPa, so the new data allowed the model to be re-evaluated. A comparison of the simulations with the experimental data shows that the model fits well below 80 GPa. However, the model did not fall within the error bars of the data for higher pressures. This is an indication that the PBX 9501 overdriven EOS products model could be modified to better match the data.

  11. ATP-reactive sites in the bacteriophage lambda packaging protein terminase lie in the N-termini of its subunits, gpA and gpNu1.

    Science.gov (United States)

    Babbar, B K; Gold, M

    1998-08-01

    ATP-reactive sites in terminase and its subunits have been successfully identified using three different affinity analogs of ATP (2-and 8-azidoATP and FITC) GpA, the larger subunit of terminase, was shown to have a higher affinity for these analogs than gpNu1, the smaller subunit. The suitability of these reagents as affinity analogs of ATP was demonstrated by ATP protection experiments and in vitro assays done with the modified proteins. These analogs were thus shown to modify the ATP-reactive sites. The results obtained from these experiments also indicate the importance of subunit-subunit interactions in the holoenzyme. Terminase, gpA, and gpNu1 were modified with these analogs and the ATP-reactive sites were identified by isolating the modified peptide by reverse-phase chromatography. The sequence analysis of the modified peptides indicates a region including amino acids 18-35 in the N-terminus of gpNu1 and a region including amino acids 59-85 in the N-terminus of gpA as being the ATP-reactive sites.

  12. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  13. Strong ideal convergence in probabilistic metric spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  14. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  15. John Strong - 1941-2006

    CERN Document Server

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  16. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.

    1988-10-01

    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  17. Strongly interacting photons and atoms

    International Nuclear Information System (INIS)

    Alge, W.

    1999-05-01

    This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)

  18. Promoting Strong Written Communication Skills

    Science.gov (United States)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  19. EVOLUTION DE L’OUVAROVITE A HAUTE PRESSION (50, 60, 70 GPa LOCALISATION DU CHROME DANS LE MANTEAU INFERIEUR TERRESTRE

    Directory of Open Access Journals (Sweden)

    I AHMED ZAID

    2001-12-01

    Full Text Available Le chrome est un élément qui rentre en faible quantité dans la composition chimique globale de la Terre. Si la localisation de certains éléments est bien connue, pour d’autres, tels le calcium et le chrome, les phases-hôtes ne sont pas encore identifiées. Des expériences de haute pression et haute température sont conduites sur un grenat riche en chrome, l’ouvarovite, de formule chimique Ca3(Cr0.54, Al0.26, Fe0.09, Ti0.112Si3O12 en vue d’identifier les phases qui pourraient accueillir le chrome dans les conditions du manteau terrestre. Les échantillons d’ouvarovite sont soumis à des pressions variant entre 50 et 70 GPa, chauffés avec un laser YAG de 60 W jusqu’à des températures de l’ordre de 2500 K et observés en microscopie électronique en transmission. Les observations et analyses montrent que dans ces conditions extrêmes, l’ouvarovite se décompose en quatre phases de haute pression : la pérovskite calcique CaSiO3 renfermant 3% d’aluminium, l’oxyde de chrome Cr2O3, l’oxyde de fer Fe2O3 et l’oxyde d’aluminium Al2O3 probablement avec des structures de corindon. Aucune nouvelle phase de haute pression du type Cr2SiO5 n’a été mise en évidence dans nos expériences. Il est probable que cet élément mineur rentre comme substitut de l’aluminium dans la pérovskite magnésienne (Mg, Fe(Si, Al, CrO3, la solubilité de l’aluminium dans cette dernière phase étant de l’ordre de 20% par mole, ou dans l’une des nombreuses phases alumineuses de haute pression telles (Ca, MgAl2Si2O8 ou Al2SiO5 mises en évidence récemment.

  20. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    Science.gov (United States)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  1. Electrodynamics of a hydrogenlike atom in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Kovarskij, V.A.; Perel'man, N.F.

    1974-01-01

    The quasienergy spectrum of the hydrogen atom in strong electromagnetic radiation is studied, the luminescence of the atom under these conditions is considered. It is shown that in a strong field the atom, being even in the ground state, radiates a spectrum of frequencies corresponding to transitions from the ground state into excited states, the strong field photons being involved. The intensity of such a luminescence is basically a non-linear function of the strong field. The exposure of the atom to two strong electromagnetic fields Ω and ω (Ω>>ω) is considered, the Ω coinciding with one of the natural frquencies of the atom. The effct of modulation of the resonance shift for an atomic level by the ω-field strength is predicted. The dependence of Ω-absorption in the ω-field on the statistic properties of the latter is investigated. (author)

  2. Diffraction plane dependence of elastic constants in ferritic steel in neutron diffraction stress measurement

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ishiwata, Masayuki; Minakawa, Noriaki; Funahashi, Satoru; Root, J.H.

    1995-01-01

    Neutron diffraction measurement have been made to investigate the diffraction plane dependence of elastic constants in ferritic steel. The measured diffraction planes were 110, 220, 112, 222 and 200. In the measurement a small tensile specimen was loaded in the tensile test rig specially designed for a neutron diffractometer. The strains obtained for five diffraction planes increased almost in proportion to the applied stress up to 230 MPa nearly equivalent to the yield stress. The mean elastic constants obtained were E=243 GPa and ν=0.28 for 110, 220 and 112, 182 GPa and 0.31 for softest 200, and 268 GPa and 0.30 for stiffest 222, respectively. The bulk elastic constants, E=222 GPa and ν=0.29, measured by the strain gauges almost agreed with the mean values for 110, 220 and 112. The Kroner elastic model is found to account for the diffraction plane dependence of Young's modulus and Poisson's ratio of the ferritic steel. (author)

  3. Semicalssical quantization of interacting anyons in a strong magnetic field

    International Nuclear Information System (INIS)

    Levit, S.; Sivan, N.

    1992-01-01

    We represent a semiclassical theory of charged interacting anyons in strong magnetic fields. We apply this theory to a number of few anyons systems including two interacting anyons in the presence of an impurity and three interacting anyons. We discuss the dependence of their energy levels on the statistical parameter and find regions in which this dependence follows very different patterns. The semiclassical arguments allow to correlate these patterns with the change in the character of the classical motion of the system. (author)

  4. A Note on Weak vs. Strong Generation in Human Language

    Directory of Open Access Journals (Sweden)

    Fukui Naoki

    2015-12-01

    Full Text Available This paper argues that various important results of formal language theory (e.g., the so-called Chomsky Hierarchy may in fact be illusory as far as the human language faculty is concerned, as has been repeatedly emphasized by Chomsky himself. The paper takes up nested dependencies and cross-serial dependencies, the two important dependencies that typically show up in the discussion of the central classes of grammars and languages, and specifically shows that the fact that nested dependencies abound in human language while cross-serial dependencies are rather limited in human language can be naturally explained if we shift our attention from dependencies defined on terminal strings to abstract structures behind them. The paper then shows that nested dependencies are readily obtained by Merge, applying phase-by-phase, whereas cross-serial dependencies are available only as a result of copying Merge, which requires a constituency of the relevant strings. These results strongly suggest that dependencies are possible in human language only to the extent that they are the results from the structures that can be generated by Merge, leading to the conclusion that it is Merge-generability that determines various dependencies in human language, and that dependencies defined on the terminal strings are indeed illusory. A possible brain science experiment to demonstrate this point is also suggested.

  5. The responses of the four main substitution mechanisms of H in olivine to H2O activity at 1050 °C and 3 GPa

    Science.gov (United States)

    Tollan, Peter M. E.; Smith, Rachel; O'Neill, Hugh St. C.; Hermann, Jörg

    2017-12-01

    The water solubility in olivine ({C}_{{H}_2O}) has been investigated at 1050 °C and 3 GPa as a function of water activity ({a}_{{H}_2O}) at subsolidus conditions in the piston-cylinder apparatus, with {a}_{{H}_2O} varied using H2O-NaCl fluids. Four sets of experiments were conducted to constrain the effect of {a}_{{H}_2O} on the four main substitution mechanisms. The experiments were designed to grow olivine in situ and thus achieve global equilibrium (G-type), as opposed to hydroxylating olivine with a pre-existing point-defect structure and impurity content (M-type). Olivine grains from the experiments were analysed with polarised and unpolarised FTIR spectroscopy, and where necessary, the spectra have been deconvoluted to quantify the contribution of each substitution mechanism. Olivine buffered with magnesiowüstite produced absorbance bands at high wavenumbers ranging from 3566 to 3612 cm-1. About 50% of the total absorbance was found parallel to the a-axis, 30% parallel to the b-axis and 20% parallel to the c-axis. The total absorbance and hence water concentration in olivine follows the relationship of {C}_{{H}_2O}∝ {a_{{H}_2O}}^2 , indicating that the investigated defect must involve four H atoms substituting for one Si atom (labelled as [Si]). Forsterite buffered with enstatite produced an absorbance band exclusively aligned parallel the c-axis at 3160 cm-1. The band position, polarisation and observed {C}_{{H}_2O}∝ {a}_{{H}_2O} are consistent with two H substituting for one Mg (labelled as [Mg]). Ti-doped, enstatite-buffered olivine displays absorption bands, and polarisation typical of Ti-clinohumite point defects where two H on the Si-site are charge-balanced by one Ti on a Mg-site (labelled as [Ti]). This is further supported by {C}_{{H}_2O}∝ {a}_{{H}_2O} and a 1:1 relationship of molar H2O and TiO2 in these experiments. Sc-doped, enstatite-buffered experiments display a main absorption band at 3355 cm-1 with {C}_{{H}_2O}∝ {a_{{H}_2O}}^{0

  6. [Correlation and concordance between the national test of medicine (ENAM) and the grade point average (GPA): analysis of the peruvian experience in the period 2007 - 2009].

    Science.gov (United States)

    Huamaní, Charles; Gutiérrez, César; Mezones-Holguín, Edward

    2011-03-01

    To evaluate the correlation and concordance between the 'Peruvian National Exam of Medicine' (ENAM) and the Mean Grade Point Average (GPA) in recently graduated medical students in the period 2007 to 2009. We carried out a secondary data analysis, using the records of the physicians applying to the Rural and Urban Marginal Service in Health of Peru (SERUMS) processes for the years 2008 to 2010. We extracted from these registers, the grades obtained in the ENAM and GPA. We performed a descriptive analysis using medians and 1st and 3rd quartiles (q1/q3); we calculated the correlation between both scores using the Spearman correlation coefficient, additionally, we conducted a lineal regression analysis, and the concordance was measured using the Bland and Altman coefficient. A total of 6 117 physicians were included, the overall median for the GPA was 13.4 (12.7/14.2) and for the ENAM was 11.6 (10.2/13.0).Of the total assessed, 36.8% failed the TEST. We observed an increase in annual median of ENAM scores, with the consequent decrease in the difference between both grades. The correlation between ENAM and PPU is direct and moderate (0.582), independent from the year, type of university management (Public or Private) and location. However, the concordance between both ratings is regular, with a global coefficient of 0.272 (CI 95%: 0.260 to 0.284). Independently of the year, location or type of university management, there is a moderate correlation between the ENAM and the PPU; however, there is only a regular concordance between both grades.

  7. Charge density analysis of SiO sub 2 under pressures over 50 GPa using a new diamond anvil cell for single-crystal structure analysis

    CERN Document Server

    Yamanaka, T; Komatsu, Y; Sumiya, H

    2002-01-01

    Single-crystal structure analysis of SiO sub 2 stishovite, (rutile type, P4 sub 2 /mnm z = 2) was carried out using the newly devised diamond anvil cell. The electron-density distribution was investigated at high pressures up to 50 GPa using synchrotron radiation at SPring-8 and a laboratory x-ray source generator of Ag K alpha rotating anode generator. Using large diamond crystal windows instead of beryllium for the cell has several advantages for single-crystal diffraction study supplying the large Q-value.

  8. Effect of low dose radiation in lymphocytes from children exposed to ionizing radiation after the Chernobyl accident. Cytogenetic, chromosome painting, GPA and adaptive response studies

    International Nuclear Information System (INIS)

    Padovani, L.; Appolloni, M.; Anzidei, P.; Spano, M.; Stronati, L.; Testa, A.; Mauro, F.

    1997-01-01

    The present study concerns the monitoring of some children coming from Byelorussian, Ukrainian and Russian republics, exposed to the fall-out, or to the initial acute dose of radiation with the aim of assessing the effects of ionizing radiation on human health and of verifying the persisting of chromosomal damage several years after the accident. Both structural chromosomes damage (conventional cytogenetic and chromosome painting) and molecular mutation (GPA) have been investigated, moreover the possible induction of an adaptive response has been tested. (author)

  9. Performance test of diamond-like carbon films for lubricating ITER blanket maintenance equipment under GPa-level high contact stress

    International Nuclear Information System (INIS)

    Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka; Shibanuma, Kiyoshi

    2007-01-01

    Diamond-like carbon (DLC) coating was tested as a candidate solid lubricant for transmission gears of the maintenance equipment of the blanket of the ITER instead of an oil lubricant. The wear tests using the pin-on-disk method were performed on disks with SCM440 and SNCM420 as the base materials and coated with soft, layered, and hard DLCs. All cases satisfied the required allowable contact stress (2 GPa) and lifetime (10 4 cycles), and therefore the feasibility of the DLC coating was validated. Among the three types of DLCs, the soft DLC showed the best performance. (author)

  10. Computational strong-field quantum dynamics intense light-matter interactions

    CERN Document Server

    2017-01-01

    This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time-dependent Schrödinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi-configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.

  11. Computational strong-field quantum dynamics. Intense light-matter interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Dieter (ed.) [Rostock Univ. (Germany). Inst. fuer Physik

    2017-09-01

    This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.

  12. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  13. Strong coupling from the Hubbard model

    Science.gov (United States)

    Minahan, Joseph A.

    2006-10-01

    It was recently observed that the one-dimensional half-filled Hubbard model reproduces the known part of the perturbative spectrum of planar {\\cal N}=4 super Yang Mills in the SU(2) sector. Assuming that this identification is valid beyond perturbation theory, we investigate the behaviour of this spectrum as the 't Hooft parameter λ becomes large. We show that the full dimension Δ of the Konishi superpartner is the solution of a sixth-order polynomial while Δ for a bare dimension 5 operator is the solution of a cubic. In both cases, the equations can be solved easily as a series expansion for both small and large λ and the equations can be inverted to express λ as an explicit function of Δ. We then consider more general operators and show how Δ depends on λ in the strong coupling limit. We are also able to distinguish those states in the Hubbard model which correspond to the gauge-invariant operators for all values of λ. Finally, we compare our results with known results for strings on AdS5 × S5, where we find agreement for a range of R-charges.

  14. Stable states in a strong IR field

    Science.gov (United States)

    Zhong, Changchun; Robicheaux, Francis

    2015-05-01

    It is found that 10% of atoms stay in the quasi-stable states after being exposed to intense laser or microwave (MW) pulses, even though the pulses' intensity is much stronger than that needed for static fields ionization. The reason why atoms survive those strong pulses has attracted growing attentions. A. Arakelyan et al. have observed the optical spectra of the surviving Lithium atoms after interaction with intense 38-GHz MW fields for more than 1000 cycles, and the spectra exhibit a periodic train of peaks 38 GHz apart. It suggests that those weakly bound Rydberg electrons seldom go back to the ionic core, where the cycle average energy exchange happens. In this study, we are interested in the electron behavior in the presence of intense infrared fields with a much shorter wavelength (1000 nm). By solving the full 3D time dependent Schrodinger equation, we calculate the spectra of the surviving atoms under intense IR fields. Our numerical calculations show atoms survive the intense field in quasi-stable states for a long time, and the optical spectra are obviously modulated by the IR frequency. Through tuning the ponderomotive energy, we see how field parameters affect the behavior of electrons. Different atoms, such as Hydrogen, Helium, Lithium, and Sodium, are tested to see how atom's energy structures influence the results.

  15. Dependent Classes

    DEFF Research Database (Denmark)

    Gasiunas, Vaidas; Mezini, Mira; Ostermann, Klaus

    2007-01-01

    of dependent classes and a machine-checked type soundness proof in Isabelle/HOL [29], the first of this kind for a language with virtual classes and path-dependent types. [29] T.Nipkow, L.C. Poulson, and M. Wenzel. Isabelle/HOL -- A Proof Assistant for Higher-Order Logic, volume 2283 of LNCS, Springer, 2002......Virtual classes allow nested classes to be refined in subclasses. In this way nested classes can be seen as dependent abstractions of the objects of the enclosing classes. Expressing dependency via nesting, however, has two limitations: Abstractions that depend on more than one object cannot...... be modeled and a class must know all classes that depend on its objects. This paper presents dependent classes, a generalization of virtual classes that expresses similar semantics by parameterization rather than by nesting. This increases expressivity of class variations as well as the flexibility...

  16. Atoms and clusters in strong laser fields

    NARCIS (Netherlands)

    Marchenko, T.

    2008-01-01

    This thesis describes experimental and theoretical studies on the interaction of strong infrared laser fields with atoms and atomic clusters. Part I provides an overview of the main strong-field phenomena in atoms, molecules and clusters and describes the state-of-the-art in strong-field science.

  17. Strong Bisimilarity of Simple Process Algebras

    DEFF Research Database (Denmark)

    Srba, Jirí

    2003-01-01

    We study bisimilarity and regularity problems of simple process algebras. In particular, we show PSPACE-hardness of the following problems: (i) strong bisimilarity of Basic Parallel Processes (BPP), (ii) strong bisimilarity of Basic Process Algebra (BPA), (iii) strong regularity of BPP, and (iv) ...

  18. 78 FR 15710 - Strong Sensitizer Guidance

    Science.gov (United States)

    2013-03-12

    ... definition of ``strong sensitizer'' found at 16 CFR 1500.3(c)(5). The Commission is proposing to revise the supplemental definition of ``strong sensitizer'' due to advancements in the science of sensitization that have... document is intended to clarify the ``strong sensitizer'' definition, assist manufacturers in understanding...

  19. Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-GPa-Strength-Grade Hot-Press-Forming Steel

    Science.gov (United States)

    Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak

    2018-03-01

    An austenitic Hadfield steel was roll-bonded with a 1.8-GPa-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 GPa was hardly achieved in conventional austenitic steels.

  20. Hydrothermal studies in a new diamond anvil cell up to 10 GPa and from -190°C to 1200°C

    Science.gov (United States)

    Bassett, W. A.; Shen, A. H.; Bucknum, M.; Chou, I.-Ming

    1993-06-01

    The new hydrothermal diamond anvil cell (HDAC) has been designed for optical microscopy and X-ray diffraction at pressures up to 10 GPa and temperatures between -190°C and 1200°C. Laser light reffected from the top and bottom anvil faces and the top and bottom solid sample faces produce interference fringes that provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in solid samples due to transitions and reactions. Synchrotron radiation has been used to make X-ray diffraction patterns of samples under hydrothermal conditions. Individual heaters and individual thermocouples provide temperature control with an accuracy of ±0.5°C. Liquid nitrogen directly introduced into the HDAC has been used to reduce the sample temperature to -190°C. The α-β phase boundary of quartz has been used to calculate the transition pressures from measured transition temperatures. With this method we have redetermined 5 isochores of H2O up to 850°C and 1.2 GPa at which the solution rate of the quartz became so rapid that the quartz dissolved completely before the α-β transition could be observed. When silica solutions were cooled, opal spherules and rods formed.

  1. Lattice dynamics at high pressure: application of inelastic X-ray scattering and ab-initio calculations -MgO at 35 GPa

    International Nuclear Information System (INIS)

    Ghose, Subrata

    2006-01-01

    Full text: Until recently, inelastic neutron scattering (INS) has been extensively used to study the phonon dispersion throughout the Brillouin zone and phonon density of states in crystalline materials. The weak interaction of neutrons with matter and the typical size of the neutron beams require the use of cm-size single crystals that puts an upper limit to the measurement of phonon dispersion at high pressure to about 10-15 Gpa by INS. Inelastic X-ray scattering (IXS) using third generation synchrotron sources now makes it possible to measure the phonon dispersion at high pressures up to 50 GP A in crystals tens of microns in size mounted in a diamond-anvil cell, usually using He as the pressure transmitting medium. We have used this technique to measure the longitudinal acoustic and optic phonon branches of MgO along the Γ-X direction at 35 Gpa. The experimentally observed phonon-branches are in remarkable agreement with ab-initio quantum mechanical calculations using the density-functional perturbation theory. The derived thermodynamic properties, such as specific heat and the entropy are in very good agreement with values obtained from a thermodynamically assessed data set

  2. Simultaneous high-pressure high-temperature elastic velocity measurement system up to 27 GPa and 1873 K using ultrasonic and synchrotron X-ray techniques

    Science.gov (United States)

    Higo, Yuji; Irifune, Tetsuo; Funakoshi, Ken-ichi

    2018-01-01

    A new pulse-echo interferometry system has been developed for measurements of sound velocity at simultaneous high pressure and temperature corresponding to those of the Earth's lower mantle, using synchrotron X-ray techniques at SPring-8. A combination of a low-noise high-frequency amplifier and a high-speed solid-state relay system allowed us to clearly detect the ultrasonic echoes of a small sample (measurement of the length of the tiny sample by X-ray radiography imaging under very high pressure and temperature. The new system was tested by measuring elastic velocities of α-Al2O3 over wide pressure and temperature ranges of up to 27 GPa and 1873 K, respectively. The resultant adiabatic bulk modulus, shear modulus, and pressure and temperature derivatives of α-Al2O3 are K0S = 251.2 (18) GPa, ∂ KS/∂ P = 4.21 (10), ∂ KS/∂ T = -0.025 (1), G = 164.1 (7), ∂ G/∂ P = 1.59 (3), ∂ G/∂ T = -0.021 (1). These values are consistent with those previously reported based on experiments at high temperatures at ambient pressure and high pressures at room temperature. The present system allows precise measurements of the elastic velocities of minerals under the pressures and temperatures corresponding to the lower mantle for the first time, which should greatly contribute to our understanding of mineralogy of the whole mantle.

  3. Upper critical field, pressure-dependent superconductivity and electronic anisotropy of Sm4Fe2As2Te(1-x)O(4-y)F(y).

    Science.gov (United States)

    Pisoni, A; Katrych, S; Szirmai, P; Náfrádi, B; Gaál, R; Karpinski, J; Forró, L

    2016-03-23

    We present a detailed study of the electrical transport properties of a recently discovered iron-based superconductor: Sm4Fe2As2Te0.72O2.8F1.2. We followed the temperature dependence of the upper critical field by resistivity measurement of single crystals in magnetic fields up to 16 T, oriented along the two main crystallographic directions. This material exhibits a zero-temperature upper critical field of 90 T and 65 T parallel and perpendicular to the Fe2As2 planes, respectively. An unprecedented superconducting magnetic anisotropy γH=H(c2)(ab)/H(c2)(c) ~ 14 is observed near Tc, and it decreases at lower temperatures as expected in multiband superconductors. Direct measurement of the electronic anisotropy was performed on microfabricated samples, showing a value of ρ(c)/ρ(ab)(300K) ~ 5 that rises up to 19 near Tc . Finally, we have studied the pressure and temperature dependence of the in-plane resistivity. The critical temperature decreases linearly upon application of hydrostatic pressure (up to 2 GPa) similarly to overdoped cuprate superconductors. The resistivity shows saturation at high temperatures, suggesting that the material approaches the Mott-Ioffe-Regel limit for metallic conduction. Indeed, we have successfully modelled the resistivity in the normal state with a parallel resistor model that is widely accepted for this state. All the measured quantities suggest strong pressure dependence of the density of states.

  4. Application of strong phosphoric acid to radiochemistry

    International Nuclear Information System (INIS)

    Terada, Kikuo

    1977-01-01

    Not only inorganic and organic compounds but also natural substrances, such as accumulations in soil, are completely decomposed and distilled by heating with strong phosphoric acid for 30 to 50 minutes. As applications of strong phosphoric acid to radiochemistry, determination of uranium and boron by use of solubilization effect of this substance, titration of uranyl ion by use of sulfuric iron (II) contained in this substance, application to tracer experiment, and determination of radioactive ruthenium in environmental samples are reviewed. Strong phosphoric acid is also applied to activation analysis, for example, determination of N in pyrographite with iodate potassium-strong phosphoric acid method, separation of Os and Ru with sulfuric cerium (IV) - strong phosphoric acid method or potassium dechromate-strong phosphoric acid method, analysis of Se, As and Sb rocks and accumulations with ammonium bromide, sodium chloride and sodium bromide-strong phosphoric acid method. (Kanao, N.)

  5. Strong Laws of Large Numbers for Arrays of Rowwise NA and LNQD Random Variables

    Directory of Open Access Journals (Sweden)

    Jiangfeng Wang

    2011-01-01

    Full Text Available Some strong laws of large numbers and strong convergence properties for arrays of rowwise negatively associated and linearly negative quadrant dependent random variables are obtained. The results obtained not only generalize the result of Hu and Taylor to negatively associated and linearly negative quadrant dependent random variables, but also improve it.

  6. Perceptual Sensitivity and Response to Strong Stimuli Are Related.

    Science.gov (United States)

    Bolders, Anna C; Tops, Mattie; Band, Guido P H; Stallen, Pieter Jan M

    2017-01-01

    To shed new light on the long-standing debate about the (in)dependence of sensitivity to weak stimuli and overreactivity to strong stimuli, we examined the relation between these tendencies within the neurobehavioral framework of the Predictive and Reactive Control Systems (PARCS) theory (Tops et al., 2010, 2014). Whereas previous studies only considered overreactivity in terms of the individual tendency to experience unpleasant affect (punishment reactivity) resulting from strong sensory stimulation, we also took the individual tendency to experience pleasant affect (reward reactivity) resulting from strong sensory stimulation into account. According to PARCS theory, these temperamental tendencies overlap in terms of high reactivity toward stimulation, but oppose each other in terms of the response orientation (approach or avoid). PARCS theory predicts that both types of reactivity to strong stimuli relate to sensitivity to weak stimuli, but that these relationships are suppressed due to the opposing relationship between reward and punishment reactivity. We measured punishment and reward reactivity to strong stimuli and sensitivity to weak stimuli using scales from the Adult Temperament Questionnaire (Evans and Rothbart, 2007). Sensitivity was also measured more objectively using the masked auditory threshold. We found that sensitivity to weak stimuli (both self-reported and objectively assessed) was positively associated with self-reported punishment and reward reactivity to strong stimuli, but only when these reactivity measures were controlled for each other, implicating a mutual suppression effect. These results are in line with PARCS theory and suggest that sensitivity to weak stimuli and overreactivity are dependent, but this dependency is likely to be obscured if punishment and reward reactivity are not both taken into account.

  7. Dependency Parsing

    CERN Document Server

    Kubler, Sandra; Nivre, Joakim

    2009-01-01

    Dependency-based methods for syntactic parsing have become increasingly popular in natural language processing in recent years. This book gives a thorough introduction to the methods that are most widely used today. After an introduction to dependency grammar and dependency parsing, followed by a formal characterization of the dependency parsing problem, the book surveys the three major classes of parsing models that are in current use: transition-based, graph-based, and grammar-based models. It continues with a chapter on evaluation and one on the comparison of different methods, and it close

  8. Quantum theory of strong-field frustrated tunneling

    Science.gov (United States)

    Popruzhenko, S. V.

    2018-01-01

    We show how the strong-field approximation, widely used for description of multiphoton and tunneling ionization, can be extended to analyse the excitation of bound states in intense low-frequency laser pulses. The proposed theory is based on the formalism of quantum trajectories and fills the gap between the numerical solution of the time-dependent Schrödinger equation and classical simulations. In particular, it allows identifying non-adiabatic and interference effects in strong-field excitation of Rydberg states.

  9. [Affective dependency].

    Science.gov (United States)

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  10. On the impact of the elastic-plastic flow upon the process of destruction of the solenoid in a super strong pulsed magnetic field

    Science.gov (United States)

    Krivosheev, S. I.; Magazinov, S. G.; Alekseev, D. I.

    2018-01-01

    At interaction of super strong magnetic fields with a solenoid material, a specific mode of the material flow forms. To describe this process, magnetohydrodynamic approximation is traditionally used. The formation of plastic shock-waves in material in a rapidly increasing pressure of 100 GPa/μs, can significantly alter the distribution of the physical parameters in the medium and affect the flow modes. In this paper, an analysis of supporting results of numerical simulations in comparison with available experimental data is presented.

  11. Atom collisions in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Smirnov, V.S.; Chaplik, A.V.

    1976-01-01

    It is shown that the long-range part of interatomic interaction is considerably altered in a strong electromagnetic field. Instead of the van der Waals law the potential asymptote can best be described by a dipole-dipole R -3 law. Impact broadening and the line shift in a strong nonresonant field are calculated. The possibility of bound states of two atoms being formed in a strong light field is discussed

  12. Elasto-viscoplastic self consistent modeling of the ambient temperature plastic behavior of periclase deformed up to 5.4 GPa

    Science.gov (United States)

    Lin, F.; Hilairet, N.; Raterron, P.; Addad, A.; Immoor, J.; Marquardt, H.; Tomé, C. N.; Miyagi, L.; Merkel, S.

    2017-11-01

    Anisotropy has a crucial effect on the mechanical response of polycrystalline materials. Polycrystal anisotropy is a consequence of single crystal anisotropy and texture (crystallographic preferred orientation) development, which can result from plastic deformation by dislocation glide. The plastic behavior of polycrystals is different under varying hydrostatic pressure conditions, and understanding the effect of hydrostatic pressure on plasticity is of general interest. Moreover, in the case of geological materials, it is useful for understanding material behavior in the deep earth and for the interpretation of seismic data. Periclase is a good material to test because of its simple and stable crystal structure (B1), and it is of interest to geosciences, as (Mg,Fe)O is the second most abundant phase in Earth's lower mantle. In this study, a polycrystalline sintered sample of periclase is deformed at ˜5.4 GPa and ambient temperature, to a total strain of 37% at average strain rates of 2.26 × 10-5/s and 4.30 × 10-5/s. Lattice strains and textures in the polycrystalline sample are recorded using in-situ synchrotron x-ray diffraction and are modeled with Elasto-Viscoplastic Self Consistent (EVPSC) methods. Parameters such as critical resolved shear stress (CRSS) for the various slip systems, strain hardening, initial grain shape, and the strength of the grain-neighborhood interaction are tested in order to optimize the simulation. At the beginning of deformation, a transient maximum occurs in lattice strains, then lattice strains relax to a "steady-state" value, which, we believe, corresponds to the true flow strength of periclase. The "steady state" CRSS of the {" separators="| 110 } ⟨" separators="| 1 1 ¯ 0 ⟩ slip system is 1.2 GPa, while modeling the transient maximum requires a CRSS of 2.2 GPa. Interpretation of the overall experimental data via modeling indicates dominant {" separators="| 110 } ⟨" separators="| 1 1 ¯ 0 ⟩ slip with initial strain

  13. Melting phase relation of nominally anhydrous, carbonated pelitic-eclogite at 2.5-3.0 GPa and deep cycling of sedimentary carbon

    Science.gov (United States)

    Tsuno, Kyusei; Dasgupta, Rajdeep

    2011-05-01

    We have experimentally investigated melting phase relation of a nominally anhydrous, carbonated pelitic eclogite (HPLC1) at 2.5 and 3.0 GPa at 900-1,350°C in order to constrain the cycling of sedimentary carbon in subduction zones. The starting composition HPLC1 (with 5 wt% bulk CO2) is a model composition, on a water-free basis, and is aimed to represent a mixture of 10 wt% pelagic carbonate unit and 90 wt% hemipelagic mud unit that enter the Central American trench. Sub-solidus assemblage comprises clinopyroxene + garnet + K-feldspar + quartz/coesite + rutile + calcio-ankerite/ankeritess. Solidus temperature is at 900-950°C at 2.5 GPa and at 900-1,000°C at 3.0 GPa, and the near-solidus melt is K-rich granitic. Crystalline carbonates persist only 50-100°C above the solidus and at temperatures above carbonate breakdown, carbon exists in the form of dissolved CO2 in silica-rich melts and as a vapor phase. The rhyodacitic to dacitic partial melt evolves from a K-rich composition at near-solidus condition to K-poor, and Na- and Ca-rich composition with increasing temperature. The low breakdown temperatures of crystalline carbonate in our study compared to those of recent studies on carbonated basaltic eclogite and peridotite owes to Fe-enrichment of carbonates in pelitic lithologies. However, the conditions of carbonate release in our study still remain higher than the modern depth-temperature trajectories of slab-mantle interface at sub-arc depths, suggesting that the release of sedimentary carbonates is unlikely in modern subduction zones. One possible scenario of carbonate release in modern subduction zones is the detachment and advection of sedimentary piles to hotter mantle wedge and consequent dissolution of carbonate in rhyodacitic partial melt. In the Paleo-NeoProterozoic Earth, on the other hand, the hotter slab-surface temperatures at subduction zones likely caused efficient liberation of carbon from subducting sedimentary carbonates. Deeply subducted

  14. Development of a simultaneous Hugoniot and temperature measurement for preheated-metal shock experiments: melting temperatures of Ta at pressures of 100 GPa.

    Science.gov (United States)

    Li, Jun; Zhou, Xianming; Li, Jiabo; Wu, Qiang; Cai, Lingcang; Dai, Chengda

    2012-05-01

    Equations of state of metals are important issues in earth science and planetary science. A major limitation of them is the lack of experimental data for determining pressure-volume and temperature of shocked metal simultaneously. By measuring them in a single experiment, a major source of systematic error is eliminated in determining from which shock pressure release pressure originates. Hence, a non-contact fast optical method was developed and demonstrated to simultaneously measure a Hugoniot pressure-volume (P(H)-V(H)) point and interfacial temperature T(R) on the release of Hugoniot pressure (P(R)) for preheated metals up to 1000 K. Experimental details in our investigation are (i) a Ni-Cr resistance coil field placed around the metal specimen to generate a controllable and stable heating source, (ii) a fiber-optic probe with an optical lens coupling system and optical pyrometer with ns time resolution to carry out non-contact fast optical measurements for determining P(H)-V(H) and T(R). The shock response of preheated tantalum (Ta) at 773 K was investigated in our work. Measured data for shock velocity versus particle velocity at an initial state of room temperature was in agreement with previous shock compression results, while the measured shock data between 248 and 307 GPa initially heated to 773 K were below the Hugoniot evaluation from its off-Hugoniot states. Obtained interfacial temperatures on release of Hugoniot pressures (100-170 GPa) were in agreement with shock-melting points at initial ambient condition and ab initio calculations of melting curve. It indicates a good consistency for shock melting data of Ta at different initial temperatures. Our combined diagnostics for Hugoniot and temperature provides an important approach for studying EOS and the temperature effect of shocked metals. In particular, our measured melting temperatures of Ta address the current controversy about the difference by more than a factor of 2 between the melting

  15. Spin quenching assisted by a strongly anisotropic compression behavior in MnP

    Energy Technology Data Exchange (ETDEWEB)

    Han, Fei; Wang, Di; Wang, Yonggang; Li, Nana; Bao, Jin-Ke; Li, Bing; Botana, Antia S.; Xiao, Yuming; Chow, Paul; Chung, Duck Young; Chen, Jiuhua; Wan, Xiangang; Kanatzidis, Mercouri G.; Yang, Wenge; Mao, Ho-Kwang

    2018-02-01

    We studied the crystal structure and spin state of MnP under high pressure with synchrotron X-ray diffraction and X-ray emission spectroscopy. MnP has an exceedingly strong anisotropy in compressibility, with the primary compressible direction along the b axis of the Pnma structure. X-ray emission spectroscopy reveals a pressure-driven quenching of the spin state in MnP. First-principles calculations suggest that the strongly anisotropic compression behavior significantly enhances the dispersion of the Mn d-orbitals and the splitting of the d-orbital levels compared to the hypothetical isotropic compression behavior. Thus, we propose spin quenching results mainly from the significant enhancement of the itinerancy of d electrons and partly from spin rearrangement occurring in the split d-orbital levels near the Fermi level. This explains the fast suppression of magnetic ordering in MnP under high pressure. The spin quenching lags behind the occurrence of superconductivity at ~8 GPa implying that spin fluctuations govern the electron pairing for superconductivity.

  16. Strong ideal convergence in probabilistic metric spaces

    Indian Academy of Sciences (India)

    sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and ... also important applications in nonlinear analysis [2]. The theory was brought to ..... for each t > 0 since each set on the right-hand side of the relation (3.1) belongs to I. Thus, by Definition 2.11 and the ...

  17. Large N baryons, strong coupling theory, quarks

    International Nuclear Information System (INIS)

    Sakita, B.

    1984-01-01

    It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)

  18. Strong decays of nucleon and delta resonances

    International Nuclear Information System (INIS)

    Bijker, R.; Leviatan, A.

    1996-01-01

    We study the strong couplings of the nucleon and delta resonances in a collective model. In the ensuing algebraic treatment we derive closed expressions for decay widths which are used to analyze the experimental data for strong decays into the pion and eta channels. (Author)

  19. Theoretical studies of strongly correlated fermions

    Energy Technology Data Exchange (ETDEWEB)

    Logan, D. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Strongly correlated fermions are investigated. An understanding of strongly correlated fermions underpins a diverse range of phenomena such as metal-insulator transitions, high-temperature superconductivity, magnetic impurity problems and the properties of heavy-fermion systems, in all of which local moments play an important role. (author).

  20. Hydrothermal crystallization in the KOH-TiO2-GeO2-H2O system at 500 deg C and 0.1 GPa

    International Nuclear Information System (INIS)

    Ilyushin, G.D.

    2003-01-01

    The identification of structural phases and crystallochemical analysis of phases in a KOH-TiO 2 -GeO 2 -H 2 O system under conditions of high temperatures and pressures are performed. A comparison is made with earlier obtained results for a system of KOH-GeO 2 (quartz-like structure)-H 2 O. It is established that K 2 Ti 6 O 13 skeleton potassium titanate is a basic phase in the system of KOH-TiO 2 -GeO 2 -H 2 O at 500 deg C and 0.1 GPa within a wide range of varying TiO 2 :GeO 2 and KOH concentrations [ru

  1. P-ρ-T measurements of H{sub 2}O up to 260 GPa under laser-driven shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, T. [Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577 (Japan); Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Ozaki, N.; Kodama, R. [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Photon Pioneers Center, Osaka University, Suita, Osaka 565-0871 (Japan); Sano, T.; Sakawa, Y. [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Okuchi, T. [Institute for Study of the Earth’s Interior, Okayama University, Misasa, Tottori 682-0193 (Japan); Sano, T.; Miyanishi, K.; Terai, T.; Kakeshita, T. [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Shimizu, K. [KYOKUGEN, Center for Science and Technology under Extreme Conditions, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2015-04-28

    Pressure, density, and temperature data for H{sub 2}O were obtained up to 260 GPa by using laser-driven shock compression technique. The shock compression technique combined with the diamond anvil cell was used to assess the equation of state models for the P-ρ-T conditions for both the principal Hugoniot and the off-Hugoniot states. The contrast between the models allowed for a clear assessment of the equation of state models. Our P-ρ-T data totally agree with those of the model based on quantum molecular dynamics calculations. These facts indicate that this model is adopted as the standard for modeling interior structures of Neptune, Uranus, and exoplanets in the liquid phase in the multi-Mbar range.

  2. Impact of Study Skills and Parent Education on First-Year GPA Among College Students With and Without ADHD: A Moderated Mediation Model.

    Science.gov (United States)

    Gormley, Matthew J; Pinho, Trevor; Pollack, Brittany; Puzino, Kristina; Franklin, Melanie K; Busch, Chelsea; DuPaul, George J; Weyandt, Lisa L; Anastopoulos, Arthur D

    2018-02-01

    To test if the relationship between ADHD and academic achievement is mediated by service utilization and/or study skills, and if these mediation effects are moderated by parental education level. A bootstrapping method within structural equation modeling was used with data from 355 first year college students meeting strict criteria for ADHD or clearly without ADHD to test the mediation and moderation effects. Study skills, but not service utilization, significantly mediated the relationship between ADHD status and GPA; however, this relationship was not significant among students with at least one parent holding a master's degree or higher. Among first year college students study skills may be a more salient predictor of educational outcomes relative to ADHD status. Additional research into support services for college students with ADHD is needed, however, results suggest interventions targeting study skills may hold particular promise for these students.

  3. Experimental determination of the H2O + 15 wt% NaCl and H2O + 25 wt% NaCl liquidi to 1.4 GPa

    Science.gov (United States)

    Valenti, P.; Schmidt, C.

    2009-12-01

    The binary H2O+NaCl is one of the most important model systems for chloridic fluids in many geologic environments such as the Earth’s crust, upper mantle, and subducting slabs, and is also applicable to extraterrestrial icy planetary bodies (e.g., Manning 2004, Zolensky et al., 1999). The knowledge on phase equilibria and PVTx properties of this system is still fragmentary at high pressures, e.g., very little has been reported on liquidi at compositions Daniel 2008). In this study, we investigated the liquidus of 15 and 25 wt% NaCl solutions at pressures up to 1.4 GPa. The experiments were performed using a hydrothermal diamond-anvil cell (Bassett et al. 1993) modified for Raman spectroscopy and accurate temperature measurements. A quartz chip, halite, and water were loaded into the sample chamber, which also contained a small trapped air bubble (10 vol%) when it was sealed. The actual salinity was then determined from measurement of the vapor-saturated liquidus temperature. The sample chamber was then compressed until the bubble disappeared. After freezing, phase transitions occurring with increasing temperature were observed optically, and the pressure was determined from the frequency shift of the 464 cm-1 Raman line of quartz (Schmidt and Ziemann 2000). The sample chamber was then compressed further, and the experiment was repeated at various bulk densities until a pressure of ~1.4 GPa was attained. At some conditions, Raman spectra were acquired for identification of the phase assemblage. The solution always crystallized to a single phase upon cooling above ~0.15 GPa at 25 wt% NaCl and above ~1 GPa at 15 wt% NaCl. Raman spectra in the OH stretching region indicate that this phase contains or is a NaCl hydrate other than hydrohalite, probably in solid solution with ice. Melting of this phase produced liquid and hydrohalite and/or ice VI. Ice VI was the last solid that dissolved upon heating, between 1100 MPa, 3 °C and 1370 MPa, 17 °C for 15 wt% NaCl and at

  4. Morphological Features of Diamond Crystals Dissolved in Fe0.7S0.3 Melt at 4 GPa and 1400°C

    Science.gov (United States)

    Sonin, V. M.; Zhimulev, E. I.; Pomazanskiy, B. S.; Zemnuhov, A. L.; Chepurov, A. A.; Afanasiev, V. P.; Chepurov, A. I.

    2018-01-01

    An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P-T parameters (4 GPa, 1400°C) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts.

  5. Perceptual Sensitivity and Response to Strong Stimuli Are Related

    Directory of Open Access Journals (Sweden)

    Anna C. Bolders

    2017-09-01

    Full Text Available To shed new light on the long-standing debate about the (independence of sensitivity to weak stimuli and overreactivity to strong stimuli, we examined the relation between these tendencies within the neurobehavioral framework of the Predictive and Reactive Control Systems (PARCS theory (Tops et al., 2010, 2014. Whereas previous studies only considered overreactivity in terms of the individual tendency to experience unpleasant affect (punishment reactivity resulting from strong sensory stimulation, we also took the individual tendency to experience pleasant affect (reward reactivity resulting from strong sensory stimulation into account. According to PARCS theory, these temperamental tendencies overlap in terms of high reactivity toward stimulation, but oppose each other in terms of the response orientation (approach or avoid. PARCS theory predicts that both types of reactivity to strong stimuli relate to sensitivity to weak stimuli, but that these relationships are suppressed due to the opposing relationship between reward and punishment reactivity. We measured punishment and reward reactivity to strong stimuli and sensitivity to weak stimuli using scales from the Adult Temperament Questionnaire (Evans and Rothbart, 2007. Sensitivity was also measured more objectively using the masked auditory threshold. We found that sensitivity to weak stimuli (both self-reported and objectively assessed was positively associated with self-reported punishment and reward reactivity to strong stimuli, but only when these reactivity measures were controlled for each other, implicating a mutual suppression effect. These results are in line with PARCS theory and suggest that sensitivity to weak stimuli and overreactivity are dependent, but this dependency is likely to be obscured if punishment and reward reactivity are not both taken into account.

  6. Moderately strong pump-induced ultrafast dynamics in solution

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H.F. [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China); University of Chinese Academy of Sciences (China); Zhang, Yizhu, E-mail: zhangyz@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); Yan, T.-M., E-mail: yantm@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); Wang, Z.Y. [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China); Jiang, Y.H., E-mail: jiangyh@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China)

    2016-09-12

    Graphical abstract: Moderately strong pump pulse is applied to the transient absorption spectrum. The pump and dump processes (resonant impulsive stimulated Raman scattering) finished in one single pump pulse in moderately strong regime make the observation of high-lying excited state dynamics possible. - Highlights: • The pulse intensity in transient absorption spectrum are experimentally studied. • The higher nonlinear susceptibility responses are observed. • The resonant impulsive stimulated Raman scattering. • New dynamics information in strong pump field. - Abstract: The transient transmittance spectra of laser dye IR144 in methanol were investigated experimentally in the moderately strong pump-probe field. Observed emission spectra in the red edge of the incident-field bandwidth, created by resonant impulsive stimulated Raman scattering (RISRS), display significant nonlinear intensity dependence as the pulse intensity increases. Dynamic perspectives of RISRS spectra can be understood well in a wavepacket picture. The excitation of high vibrational levels in the ground electronic state leading to the redshift of emissions presents high dependence of the pump-pulse intensity and ultrafast dynamical features, mapping the spatial overlap and separation of ground and excited wave functions and resolving the ultrafast vibrational relaxation in the femtosecond regime.

  7. Seismic switch for strong motion measurement

    Science.gov (United States)

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  8. Rietveld refinement study of the pressure dependence of the internal structural parameter u in the wurtzite phase of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.; Ding, Y.; Somayazulu, M.; Qian, J.; Shu, J.; Hausermann, D.; Mao, H.-k. (CIW); (LANL)

    2010-07-19

    The pressure dependence of the internal structural parameter u of the wurtzite phase of ZnO was studied using high resolution angular dispersive x-ray diffraction up to 12 GPa in a helium pressure medium. The u parameter increases with pressure up to about 0.430 at about 5.6 GPa, and then rapidly decrease to about 0.380 during the phase transition. Two models of the phase transition path were proposed recently by first-principles calculations [A. M. Saitta and F. Decremps, Phys. Rev. B 70, 035214 (2004); S. Limpijumnong and S. Jungthawan, Phys. Rev. B 70, 054104 (2004)]. These possible mechanisms responsible for the wurtzite-to-rocksalt phase transition under high pressure are experimentally evaluated based on our results. The bulk moduli of the wurtzite and rocksalt phase at zero pressure were estimated as 135.3 {+-} 1.8 and 177.4 {+-} 4.6 GPa, respectively.

  9. High-pressure investigations on Piplia Kalan eucrite meteorite using in-situ X-ray diffraction and 57Fe Mössbauer spectroscopic technique up to 16 GPa

    Directory of Open Access Journals (Sweden)

    Usha Chandra

    2016-03-01

    Full Text Available We report here high-pressure investigations on Piplia Kalan eucrite–a member of HED (Howardite–Eucrite–Diogenite family from asteroid 4-Vesta based on synchrotron X-ray diffraction (up to 16 GPa and 57Fe Mössbauer spectroscopy (up to 8 GPa. Dominant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining amorphous character at 16 GPa. These phase transitions of individual components could be explained simultaneously through variations in high-pressure XRD patterns and the Mössbauer parameters. Most prominent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in Mössbauer parameters and population inversion of Fe2+ in M1 and M2 sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of ∼12 GPa implied residual stress experienced due to shock impact. The presence of high pressure (monoclinic phase of pigeonite and ferrosilite at ambient condition in this eucrite sample confirmed earlier suggestions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences amongst HED members.

  10. Strong and superstrong pulsed magnetic fields generation

    CERN Document Server

    Shneerson, German A; Krivosheev, Sergey I

    2014-01-01

    Strong pulsed magnetic fields are important for several fields in physics and engineering, such as power generation and accelerator facilities. Basic aspects of the generation of strong and superstrong pulsed magnetic fields technique are given, including the physics and hydrodynamics of the conductors interacting with the field as well as an account of the significant progress in generation of strong magnetic fields using the magnetic accumulation technique. Results of computer simulations as well as a survey of available field technology are completing the volume.

  11. Impurity screening in strongly coupled plasma systems

    CERN Document Server

    Kyrkos, S

    2003-01-01

    We present an overview of the problem of screening of an impurity in a strongly coupled one-component plasma within the framework of the linear response (LR) theory. We consider 3D, 2D and quasi-2D layered systems. For a strongly coupled plasma the LR can be determined by way of the known S(k) structure functions. In general, an oscillating screening potential with local overscreening and antiscreening regions emerges. In the case of the bilayer, this phenomenon becomes global, as overscreening develops in the layer of the impurity and antiscreening in the adjacent layer. We comment on the limitations of the LR theory in the strong coupling situation.

  12. Thermalization and confinement in strongly coupled gauge theories

    Directory of Open Access Journals (Sweden)

    Ishii Takaaki

    2016-01-01

    Full Text Available Quantum field theories of strongly interacting matter sometimes have a useful holographic description in terms of the variables of a gravitational theory in higher dimensions. This duality maps time dependent physics in the gauge theory to time dependent solutions of the Einstein equations in the gravity theory. In order to better understand the process by which “real world” theories such as QCD behave out of thermodynamic equilibrium, we study time dependent perturbations to states in a model of a confining, strongly coupled gauge theory via holography. Operationally, this involves solving a set of non-linear Einstein equations supplemented with specific time dependent boundary conditions. The resulting solutions allow one to comment on the timescale by which the perturbed states thermalize, as well as to quantify the properties of the final state as a function of the perturbation parameters. We comment on the influence of the dual gauge theory’s confinement scale on these results, as well as the appearance of a previously anticipated universal scaling regime in the “abrupt quench” limit.

  13. Strong Coupling Corrections in Quantum Thermodynamics

    Science.gov (United States)

    Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

    2018-03-01

    Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

  14. Finding quantum effects in strong classical potentials

    Science.gov (United States)

    Hegelich, B. Manuel; Labun, Lance; Labun, Ou Z.

    2017-06-01

    The long-standing challenge to describing charged particle dynamics in strong classical electromagnetic fields is how to incorporate classical radiation, classical radiation reaction and quantized photon emission into a consistent unified framework. The current, semiclassical methods to describe the dynamics of quantum particles in strong classical fields also provide the theoretical framework for fundamental questions in gravity and hadron-hadron collisions, including Hawking radiation, cosmological particle production and thermalization of particles created in heavy-ion collisions. However, as we show, these methods break down for highly relativistic particles propagating in strong fields. They must therefore be improved and adapted for the description of laser-plasma experiments that typically involve the acceleration of electrons. Theory developed from quantum electrodynamics, together with dedicated experimental efforts, offer the best controllable context to establish a robust, experimentally validated foundation for the fundamental theory of quantum effects in strong classical potentials.

  15. The Charm and Beauty of Strong Interactions

    Science.gov (United States)

    El-Bennich, Bruno

    2018-01-01

    We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.

  16. Atomica ionization by strong coherent radiation

    International Nuclear Information System (INIS)

    Brandi, H.S.; Davidovich, L.

    1979-07-01

    The relation among the three most frequently used non-perturbative methods proposed to study the ionization of atoms by strong electromagnetic fields is established. Their range of validity is also determined. (Author) [pt

  17. Perturbation of an exact strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1982-10-01

    Perturbations of an exact strong gravity solution are investigated. It is shown, by using the new multipole expansions previously presented, that this exact and static spherically symmetric solution is stable under odd parity perturbations. (author)

  18. Strong-force theorists scoop Noble Prize

    CERN Multimedia

    Durrani, Matin

    2004-01-01

    Three US theorists have shared the 2004 Nobel Prize in Physics "for the discovery of asymptotic freedom in the theory of the strong interaction". Their theoretical work explains why quarks behave almost as free particles at high energies (½ page)

  19. Calculating hadronic properties in strong QCD

    International Nuclear Information System (INIS)

    Pennington, M.R.

    1996-01-01

    This talk gives a brief review of the progress that has been made in calculating the properties of hadrons in strong QCD. In keeping with this meeting I will concentrate on those properties that can be studied with electromagnetic probes. Though perturbative QCD is highly successful, it only applies in a limited kinematic regime, where hard scattering occur, and the quarks move in the interaction region as if they are free, pointlike objects. However, the bulk of strong interactions are governed by the long distance regime, where the strong interaction is strong. It is this regime of length scales of the order of a Fermi, that determines the spectrum of light hadrons and their properties. The calculation of these properties requires an understanding of non-perturbative QCD, of confinement and chiral symmetry breaking. (author)

  20. Solubility of Sulfur in Shergottitic Silicate Melts Up to 0.8 GPA: Implications for S Contents of Shergottites

    Science.gov (United States)

    Righter, K.; Pando, K.M.; Danielson, L.

    2009-01-01

    Shergottites have high S contents (1300 to 4600 ppm; [1]), but it is unclear if they are sulfide saturated or under-saturated. This issue has fundamental implications for determining the long term S budget of the martian surface and atmosphere (from mantle degassing), as well as evolution of the highly siderophile elements (HSE) Au, Pd, Pt, Re, Rh, Ru, Ir, and Os, since concentrations of the latter are controlled by sulfide stability. Resolution of sulfide saturation depends upon temperature, pressure, oxygen fugacity (and FeO), and magma composition [2]. Expressions derived from experimental studies allow prediction of S contents, though so far they are not calibrated for shergottitic liquids [3-5]. We have carried out new experiments designed to test current S saturation models, and then show that existing calibrations are not suitable for high FeO and low Al2O3 compositions characteristic of shergottitic liquids. The new results show that existing models underpredict S contents of sulfide saturated shergottitic liquids by a factor of 2.

  1. Building strong brands – does it matter?

    OpenAIRE

    Aure, Kristin Gaaseide; Nervik, Kristine Dybvik

    2014-01-01

    Brand equity has proven, through several decades of research, to be a primary source of competitive advantage and future earnings (Yoo & Donthu, 2001). Building strong brands has therefore become a priority for many organizations, with the presumption that building strong brands yields these advantages (Yasin et al., 2007). A quantitative survey was conducted at Sunnmøre in Norway in order to answer the two developed research questions. - Does the brand equity dimensions; brand...

  2. Algebra of strong and electroweak interactions

    International Nuclear Information System (INIS)

    Bolokhov, S.V.; Vladimirov, Yu.S.

    2004-01-01

    The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru

  3. Ontological dependency

    NARCIS (Netherlands)

    Stamper, R.K.

    1996-01-01

    Successful ontological analysis depends upon having the right underlying theory. The work described here, exploring how to understand organisations as systems of social norms found that the familiar objectivist position did not work, eventually replacing it with a radically subjectivist ontology

  4. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  5. Hydrothermal Diamond Anvil Cell Investigations Into the Alumina-Silica-Water System up to 1073 K and 4 GPa

    Science.gov (United States)

    Davis, M. K.; Stixrude, L. P.

    2004-12-01

    Understanding fluid chemistry in the subduction zone environment is key to unraveling the details of element transport from the slab to the surface. Solubility of different mineral assemblages in predominantly water-rich fluid along with pressure and temperature conditions control the chemical structure of the aqueous fluid and govern the transport opportunities for various chemical components away from the subducting slab. In-situ Raman experiments were performed in the alumina-silica-water system in an externally heated Bassett-type hydrothermal diamond anvil cell in the Department of Geological Sciences at the University of Michigan. Natural quartz samples (from the Owl Creek Mountains, Wyoming) were used as the silica source and synthetic ruby was used for the alumina source. Temperatures inside the diamond cell were monitored using type-K thermocouples wrapped around the diamonds and the pressure calibrated by the Raman shift of diamond or quartz or the fluorescence of ruby depending on conditions. Raman measurements of the aluminosilicate fluid show the presence of multiple alumina, silica, and mixed species. As predicted by calculations an aluminosilicate specie possibly of the form (HO)3SiOAl(OH)32- as well as the silica monomer and dimer specie were observed in the aluminosilicate fluid. There also appeared to be at least one hydrous alumina specie based on the presence of a Raman peaks at 228 cm-1, 339 cm-1 and 970 cm-1 in the fluid and a comparative analysis between Raman peaks in aqueous fluid in the silica-water, alumina-water, and alumina-silica-water systems. Solid phases formed during experiments (diaspore, kyanite) were confirmed with Raman spectroscopy.

  6. Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

  7. The extended reciprocity: Strong belief outperforms persistence.

    Science.gov (United States)

    Kurokawa, Shun

    2017-05-21

    The existence of cooperation is a mysterious phenomenon and demands explanation, and direct reciprocity is one key potential explanation for the evolution of cooperation. Direct reciprocity allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior. Here, relevant to direct reciprocity is information deficiency. When the opponent's last move is unknown, how should players behave? One possibility is to choose cooperation with some default probability without using any further information. In fact, our previous paper (Kurokawa, 2016a) examined this strategy. However, there might be beneficial information other than the opponent's last move. A subsequent study of ours (Kurokawa, 2017) examined the strategy which uses the own last move when the opponent's last move is unknown, and revealed that referring to the own move and trying to imitate it when information is absent is beneficial. Is there any other beneficial information else? How about strong belief (i.e., have infinite memory and believe that the opponent's behavior is unchanged)? Here, we examine the evolution of strategies with strong belief. Analyzing the repeated prisoner's dilemma game and using evolutionarily stable strategy (ESS) analysis against an invasion by unconditional defectors, we find the strategy with strong belief is more likely to evolve than the strategy which does not use information other than the opponent player's last move and more likely to evolve than the strategy which uses not only the opponent player's last move but also the own last move. Strong belief produces the extended reciprocity and facilitates the evolution of cooperation. Additionally, we consider the two strategies game between strategies with strong belief and any strategy, and we consider the four strategies game in which unconditional cooperators, unconditional defectors, pessimistic reciprocators with strong belief, and optimistic reciprocators with

  8. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    FPE) in rapidity space analytically for the case of a time-dependent diffusion coefficient. The solutions represent SPS data for 158 A•GeV/c Pb+Pb very well. With the dependence of the rapidity relaxation coeffi- cients on the available relativistic ...

  9. Single-Crystal X-Ray Diffraction of Orthoenstatite to 48 GPa: New High-Pressure Phases with 4-, 5-, and 6-Coordinated Silicon

    Science.gov (United States)

    Finkelstein, G. J.; Dera, P. K.; Duffy, T. S.

    2013-12-01

    Orthopyroxene (opx, (Mg,Fe)SiO3) is one of the major phases in Earth's upper mantle, comprising ~20% of the region by volume. At high pressures and temperatures, this phase undergoes several well-characterized phase transitions. Its behavior at low temperature is less well known, but may be important for cold subducting slabs (1, 2). Previous studies (3, 4) reported that MgSiO3 orthoenstatite persists up to ~12 GPa, and a phase transition above this pressure was recently discovered by Zhang et al. (5). This structure, which we call β-opx (designated HPCEN2 in previous studies), is related to one predicted by theory (6), and has P21/c monoclinic symmetry. It retains an opx topology despite its lower symmetry, distinguishing it from a true clinopyroxene. We conducted single-crystal X-ray diffraction experiments in a diamond anvil cell at GSECARS and HPCAT at the APS. Mg0.91Fe0.09SiO3 orthopyroxene was compressed in a neon pressure medium with a gold pressure standard. In addition to the orthopyroxene to β-opx transition, we observe two further phase changes at ~28 GPa and ~38 GPa. The transitions result in volume reductions of ~2.5% and ~3.9%, respectively. The Si layers in both new structures are intermediate between the opx structure and that of the ilmenite-structured akimotoite polymorph. Akimotoite consists of edge-sharing MgO6 and SiO6 octahedra arranged in alternating honeycomb sheets. A theoretical study suggested clinoenstatite could transform directly to akimotoite at low temperatures through a shear-based mechanism (7). Here, we observe that the path toward akimotoite-like Si layers is stepwise. In the new MgSiO3 structures, the initial chains of SiO4 tetrahedra are partially converted to the characteristic 6-coordinated honeycomb layers. This results in some 5-coordinated Si sites in both structures. Due to the increased coordination number, we are calling the new structures α- and β-post-orthopyroxene (α-popx and β-popx). The Mg layers, however, do

  10. A strongly coupled quark-gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shuryak, Edward [Department of Physics and Astronomy, University at Stony Brook, NY 11794 (United States)

    2004-08-01

    Successful description of robust collective flow phenomena at RHIC by ideal hydrodynamics, recent observations of bound c-barc,q-barq states on the lattice, and other theoretical developments indicate that QGP produced at RHIC, and probably in a wider temperature region T{sub c} < T < 4T{sub c}, is not a weakly coupled quasiparticle gas as believed previously. We discuss how strong the interaction is and why it seems to generate hundreds of binary channels with bound states, surviving well inside the QGP phase. We in particular discuss their effect on pressure and viscosity. We conclude by reviewing the similar phenomena for other 'strongly coupled systems', such as (i) strongly coupled supersymmetric theories studied via Maldacena duality; (ii) trapped ultra-cold atoms with very large scattering length, tuned to Feschbach resonances.

  11. Strong Coupling between Plasmons and Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Joel Bellessa

    2014-05-01

    Full Text Available In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed.

  12. A theory of the strong interactions

    International Nuclear Information System (INIS)

    Gross, D.J.

    1979-01-01

    The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)

  13. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  14. Patterns of Strong Coupling for LHC Searches

    CERN Document Server

    Liu, Da; Rattazzi, Riccardo; Riva, Francesco

    2016-11-23

    Even though the Standard Model (SM) is weakly coupled at the Fermi scale, a new strong dynamics involving its degrees of freedom may conceivably lurk at slightly higher energies, in the multi TeV range. Approximate symmetries provide a structurally robust context where, within the low energy description, the dimensionless SM couplings are weak, while the new strong dynamics manifests itself exclusively through higher-derivative interactions. We present an exhaustive classification of such scenarios in the form of effective field theories, paying special attention to new classes of models where the strong dynamics involves, along with the Higgs boson, the SM gauge bosons and/or the fermions. The IR softness of the new dynamics suppresses its effects at LEP energies, but deviations are in principle detectable at the LHC, even at energies below the threshold for production of new states. Our construction provides the so far unique structurally robust context where to motivate several searches in Higgs physics, d...

  15. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

    Electronic structure and physical properties of strongly correlated materials containing elements with partially filled 3d, 4d, 4f and 5f electronic shells is analyzed by Dynamical Mean-Field Theory (DMFT). DMFT is the most universal and effective tool used for the theoretical investigation of electronic states with strong correlation effects. In the present book the basics of the method are given and its application to various material classes is shown. The book is aimed at a broad readership: theoretical physicists and experimentalists studying strongly correlated systems. It also serves as a handbook for students and all those who want to be acquainted with fast developing filed of condensed matter physics.

  16. Aperture averaging in strong oceanic turbulence

    Science.gov (United States)

    Gökçe, Muhsin Caner; Baykal, Yahya

    2018-04-01

    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

  17. Electromagnetic Processes in strong Crystalline Fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  18. Emerging signs of strong reciprocity in human ontogeny

    Directory of Open Access Journals (Sweden)

    Erin eRobbins

    2011-12-01

    Full Text Available Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny. Three- and five-year-old middle class American children (N=162 were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By three years, American children demonstrate a willingness to engage in costly punishment. However, only five-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and 3 additional control conditions demonstrate that such propensity is not simply reducible to a straight imitation, or b inequity aversion. To assess the relative universality of such development, a group of five- to six-year-old children from rural Samoa (N=14 were tested and compared to age and gender matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to 1 the developmental emergence of an ethical stance between three and five years of age, and 2 that the expression of such stance by young children could depend on culture.

  19. Membrane-mediated interaction between strongly anisotropic protein scaffolds.

    Directory of Open Access Journals (Sweden)

    Yonatan Schweitzer

    2015-02-01

    Full Text Available Specialized proteins serve as scaffolds sculpting strongly curved membranes of intracellular organelles. Effective membrane shaping requires segregation of these proteins into domains and is, therefore, critically dependent on the protein-protein interaction. Interactions mediated by membrane elastic deformations have been extensively analyzed within approximations of large inter-protein distances, small extents of the protein-mediated membrane bending and small deviations of the protein shapes from isotropic spherical segments. At the same time, important classes of the realistic membrane-shaping proteins have strongly elongated shapes with large and highly anisotropic curvature. Here we investigated, computationally, the membrane mediated interaction between proteins or protein oligomers representing membrane scaffolds with strongly anisotropic curvature, and addressed, quantitatively, a specific case of the scaffold geometrical parameters characterizing BAR domains, which are crucial for membrane shaping in endocytosis. In addition to the previously analyzed contributions to the interaction, we considered a repulsive force stemming from the entropy of the scaffold orientation. We computed this interaction to be of the same order of magnitude as the well-known attractive force related to the entropy of membrane undulations. We demonstrated the scaffold shape anisotropy to cause a mutual aligning of the scaffolds and to generate a strong attractive interaction bringing the scaffolds close to each other to equilibrium distances much smaller than the scaffold size. We computed the energy of interaction between scaffolds of a realistic geometry to constitute tens of kBT, which guarantees a robust segregation of the scaffolds into domains.

  20. Experimental investigation of strong field trident production

    CERN Document Server

    Esberg, J; Knudsen, H; Thomsen, H D; Uggerhøj, E; Uggerhøj, U I; Sona, P; Mangiarotti, A; Ketel, T J; Dizdar, A; Dalton, M M; Ballestrero, S; Connell, S H

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single crystals. For the amorphous material our data are in good agreement with theory, whereas a discrepancy with theory on the magnitude of the trident enhancement is found in the precisely aligned case where the strong electric field acts.

  1. Gluon scattering amplitudes at strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Maldacena, Juan [School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2007-06-15

    We describe how to compute planar gluon scattering amplitudes at strong coupling in N = 4 super Yang Mills by using the gauge/string duality. The computation boils down to finding a certain classical string configuration whose boundary conditions are determined by the gluon momenta. The results are infrared divergent. We introduce the gravity version of dimensional regularization to define finite quantities. The leading and subleading IR divergencies are characterized by two functions of the coupling that we compute at strong coupling. We compute also the full finite form for the four point amplitude and we find agreement with a recent ansatz by Bern, Dixon and Smirnov.

  2. Strong boundedness of analytic functions in tubes

    Directory of Open Access Journals (Sweden)

    Richard D. Carmichael

    1979-01-01

    Full Text Available Certain classes of analytic functions in tube domains TC=ℝn+iC in n-dimensional complex space, where C is an open connected cone in ℝn, are studied. We show that the functions have a boundedness property in the strong topology of the space of tempered distributions g′. We further give a direct proof that each analytic function attains the Fourier transform of its spectral function as distributional boundary value in the strong (and weak topology of g′.

  3. Thermodynamical instabilities under strong magnetic fields

    Science.gov (United States)

    Chen, Y. J.

    2017-03-01

    The thermodynamical instabilities of low densities in the n p matter and n p e matter are studied within several relativistic nuclear models under some values of magnetic fields. The results are compared between each other and the effects of the symmetry energy slope at saturation density on the instability are investigated. The instability regions can exhibit bands due to the presence of Landau levels for very strong magnetic fields of the order of 1017 G, while for weaker magnetic fields, the bands are replaced by many diffused or scattered pieces. It also shows that the proton fraction in the inner crust of neutron stars may be complex under strong magnetic fields.

  4. Universal behavior of strongly correlated Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Shaginyan, Vasilii R [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation); Amusia, M Ya [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation); Popov, Konstantin G [Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar (Russian Federation)

    2007-06-30

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T{sub c} superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  5. Universal behavior of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Shaginyan, Vasilii R; Amusia, M Ya; Popov, Konstantin G

    2007-01-01

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T c superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  6. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  7. De Sitter vacua of strongly interacting QFT

    Energy Technology Data Exchange (ETDEWEB)

    Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)

    2017-03-22

    We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.

  8. Strong-field short-pulse nondipole dynamics

    DEFF Research Database (Denmark)

    Dimitrovski, Darko; Førre, Morten; Madsen, Lars Bojer

    2009-01-01

    We present a quantitative investigation of strong-field short-pulse nondipole dynamics in laser-matter interactions. We find excellent agreement between ab initio numerical and analytic results obtained using the Magnus expansion. We show that in the short-pulse limit, ultrafast transfer and cont......We present a quantitative investigation of strong-field short-pulse nondipole dynamics in laser-matter interactions. We find excellent agreement between ab initio numerical and analytic results obtained using the Magnus expansion. We show that in the short-pulse limit, ultrafast transfer...... and control of population can be achieved using nondipole effects. The relative importance of nondipole to dipole effects depends on the displacement imparted to a free classical electron....

  9. Combined incomplete LU and strongly implicit procedure preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Meese, E.A. [Univ. of Trondheim (Norway)

    1996-12-31

    For the solution of large sparse linear systems of equations, the Krylov-subspace methods have gained great merit. Their efficiency are, however, largely dependent upon preconditioning of the equation-system. A family of matrix factorisations often used for preconditioning, is obtained from a truncated Gaussian elimination, ILU(p). Less common, supposedly due to it`s restriction to certain sparsity patterns, is factorisations generated by the strongly implicit procedure (SIP). The ideas from ILU(p) and SIP are used in this paper to construct a generalized strongly implicit procedure, applicable to matrices with any sparsity pattern. The new algorithm has been run on some test equations, and efficiency improvements over ILU(p) was found.

  10. Remarks on the strong maximum principle for nonlocal operators

    Directory of Open Access Journals (Sweden)

    Jerome Coville

    2008-05-01

    Full Text Available In this note, we study the existence of a strong maximum principle for the nonlocal operator $$ mathcal{M}[u](x :=int_{G}J(gu(x*g^{-1}dmu(g - u(x, $$ where $G$ is a topological group acting continuously on a Hausdorff space $X$ and $u in C(X$. First we investigate the general situation and derive a pre-maximum principle. Then we restrict our analysis to the case of homogeneous spaces (i.e., $ X=G /H$. For such Hausdorff spaces, depending on the topology, we give a condition on $J$ such that a strong maximum principle holds for $mathcal{M}$. We also revisit the classical case of the convolution operator (i.e. $G=(mathbb{R}^n,+, X=mathbb{R}^n, dmu =dy$.

  11. Joint statistics of strongly correlated neurons via dimensionality reduction

    Science.gov (United States)

    Deniz, Taşkın; Rotter, Stefan

    2017-06-01

    The relative timing of action potentials in neurons recorded from local cortical networks often shows a non-trivial dependence, which is then quantified by cross-correlation functions. Theoretical models emphasize that such spike train correlations are an inevitable consequence of two neurons being part of the same network and sharing some synaptic input. For non-linear neuron models, however, explicit correlation functions are difficult to compute analytically, and perturbative methods work only for weak shared input. In order to treat strong correlations, we suggest here an alternative non-perturbative method. Specifically, we study the case of two leaky integrate-and-fire neurons with strong shared input. Correlation functions derived from simulated spike trains fit our theoretical predictions very accurately. Using our method, we computed the non-linear correlation transfer as well as correlation functions that are asymmetric due to inhomogeneous intrinsic parameters or unequal input.

  12. [Dependency syndrome].

    Science.gov (United States)

    Vuorisalo, Sailaritta

    2013-01-01

    The most common causes of lower limb edema include cardiac insufficiency, venous insufficiency, insufficiency of lymph flow, and side effects of drugs. It can also be due to dependency syndrome, in which the edema and skin changes can only be explained by a passive calf muscle pump and the resulting venous hypertension. Underlying the drop foot is always immobilization for one reason or other. The patient must be given an explanation about the situation, activated to move if possible, and in any case guided to the use of support stockings and postural therapy.

  13. Semi-metallic, strong and stretchable wet-spun conjugated polymer microfibers

    KAUST Repository

    Zhou, Jian

    2015-01-21

    A dramatic improvement in electrical conductivity is necessary to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators. In this study, high-performance poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet-spinning followed by hot-drawing. Due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), we achieved a record electrical conductivity of 2804 S cm−1. This is, to the best of our knowledge, a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S cm−1) and a two-fold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S cm−1). Moreover, we found that these highly conductive fibers experience a semiconductor–metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers described here could make them available for conductive smart electronics.

  14. Earthquake source model using strong motion displacement

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  15. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    probes like photons, pions or protons or the heated and compressed hadronic matter generated in a heavy-ion collision. Leaving any nuclear medium without strong final-state interactions, dileptons are the optimum decay channel as they avoid any final-state distortion of the 4- momenta of the decay products entering eq.

  16. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    Properties of hadrons in strongly interacting matter provide a link between quantum chromodynamics in the ... Top: Spectral function of the ρ-meson at normal nuclear matter density as a function of mass and ... directly but folded with the branching ratio ΓV →p1+p2 /Γtot into the specific final channel one is investigating.

  17. Strong industrial base vital for economic revival

    CERN Multimedia

    2001-01-01

    At the inauguration of a 2-day conference on nuclear technology in Islamabad, the chairman of PAEC said that Pakistan needs to develop a strong industrial base and capability to export equipment to improve the economic condition of the country. He descibed how Pakistan has already had a breakthrough with the export of equipment to CERN, Geneva (1 page).

  18. Chaos desynchronization in strongly coupled systems

    International Nuclear Information System (INIS)

    Wu Ye; Liu Weiqing; Xiao, Jinghua; Zhan Meng

    2007-01-01

    The dynamics of chaos desynchronization in strongly coupled oscillator systems is studied. We find a new bifurcation from synchronous chaotic state, chaotic short wave bifurcation, i.e. a chaotic desynchronization attractor is new born in the systems due to chaos desynchronization. In comparison with the usual periodic short wave bifurcation, very rich but distinct phenomena are observed

  19. Strong wind climatic zones in South Africa

    CSIR Research Space (South Africa)

    Kruger, AC

    2010-01-01

    Full Text Available In this paper South Africa is divided into strong wind climate zones, which indicate the main sources of annual maximum wind gusts. By the analysis of wind gust data of 94 weather stations, which had continuous climate time series of 10 years...

  20. Reducing Weak to Strong Bisimilarity in CCP

    Directory of Open Access Journals (Sweden)

    Andrés Aristizábal

    2012-12-01

    Full Text Available Concurrent constraint programming (ccp is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes evolve by posting and querying (partial information in a global medium. Bisimilarity is a standard behavioural equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for ccp, and a ccp partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimiliarity is a central behavioural equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity; a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for ccp. We give an alternative reduction from weak ccp bisimilarity to the strong one that allows us to use the ccp partition refinement algorithm for deciding this equivalence.

  1. Strong motion duration and earthquake magnitude relationships

    International Nuclear Information System (INIS)

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ''strong motion duration'' has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions

  2. Morphological modelling of strongly curved islands

    NARCIS (Netherlands)

    Roelvink, D.; Den Heijer, C.; Van Thiel De Vries, J.S.M.

    2013-01-01

    Land reclamations and island coasts often involve strongly curved shorelines, which are challenging to be properly modeled by numerical morphological models. Evaluation of the long term development of these types of coasts as well as their response to storm conditions requires proper representation

  3. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...

  4. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  5. Experimental investigation of strong field trident production

    NARCIS (Netherlands)

    Esberg, J.; Kirsebom, K.; Knudsen, H.; Thomsen, H.D.; Uggerhøj, E.; Uggerhøj, U.I.; Sona, P.; Mangiarotti, A.; Ketel, T.J.; Ditzdar, A.; Dalton, M.M.; Ballestrero, S.; Connell, S.H.

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single

  6. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    hanced values needed to interpret the data at higher energies point towards the importance of strong-coupling effects. ... when all secondary particles have been created. For short times in the initial phase ... It is decisive for a proper representation of the available data for relativistic heavy-ion collisions at and beyond SPS.

  7. Bottomonia: open bottom strong decays and spectrum

    Directory of Open Access Journals (Sweden)

    Santopinto E.

    2014-05-01

    Full Text Available We present our results for the bottomonium spectrum with self energy corrections. The bare masses used in the calculation are computed within Godfrey and Isgur’s relativized quark model. We also discuss our results for the open bottom strong decay widths of higher bottomonia in the 3P0 pair-creation model.

  8. Strong motion duration and earthquake magnitude relationships

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, M.W.; Short, S.A. [EQE International, Inc., San Francisco, CA (United States); Kennedy, R.P. [RPK Structural Mechanics Consulting, Yorba Linda, CA (United States)

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

  9. Controlling Josephson dynamics by strong microwave fields

    NARCIS (Netherlands)

    Chesca, B.; Savel'ev, E.; Rakhmanov, A.L.; Smilde, H.J.H.; Hilgenkamp, Johannes W.M.

    2008-01-01

    We observe several sharp changes in the slope of the current-voltage characteristics (CVCs) of thin-film ramp-edge Josephson junctions between YBa2Cu3O7−delta and Nb when applying strong microwave fields. Such behavior indicates an intriguing Josephson dynamics associated with the switching from a

  10. Weak and strong nonlinearities in magnetic bearings

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav

    2004-01-01

    Roč. 39, č. 7 (2004), s. 779-795 ISSN 0094-114X R&D Projects: GA ČR GA101/00/1471; GA AV ČR IBS2076301 Institutional research plan: CEZ:AV0Z2076919 Keywords : weak nonlinearitiy * strong nonlinearity * magnetics bearings Subject RIV: BI - Acoustics Impact factor: 0.605, year: 2004

  11. Rotating compressible fluids under strong stratification

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Lu, Y.; Novotný, A.

    2014-01-01

    Roč. 19, October (2014), s. 11-18 ISSN 1468-1218 Keywords : rotating fluid * compressible Navier-Stokes * strong stratification Subject RIV: BA - General Mathematics Impact factor: 2.519, year: 2014 http://www.sciencedirect.com/science/article/pii/S1468121814000212#

  12. Super-strong Magnetic Field in Sunspots

    Science.gov (United States)

    Okamoto, Takenori J.; Sakurai, Takashi

    2018-01-01

    Sunspots are the most notable structure on the solar surface with strong magnetic fields. The field is generally strongest in a dark area (umbra), but sometimes stronger fields are found in non-dark regions, such as a penumbra and a light bridge. The formation mechanism of such strong fields outside umbrae is still puzzling. Here we report clear evidence of the magnetic field of 6250 G, which is the strongest field among Stokes I profiles with clear Zeeman splitting ever observed on the Sun. The field was almost parallel to the solar surface and located in a bright region sandwiched by two opposite-polarity umbrae. Using a time series of spectral data sets, we discuss the formation process of the super-strong field and suggest that this strong field region was generated as a result of compression of one umbra pushed by the horizontal flow from the other umbra, such as the subduction of the Earth’s crust in plate tectonics.

  13. Strongly coupled semidirect mediation of supersymmetry breaking

    International Nuclear Information System (INIS)

    Ibe, M.; Izawa, K.-I.; Nakai, Y.

    2009-01-01

    Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard-model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard-model gaugino masses for a small mediator mass without breaking the standard-model symmetries.

  14. A Note on Strongly Dense Matrices

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.

    2015-01-01

    Roč. 1, č. 4 (2015), s. 721-730 ISSN 2199-675X Institutional support: RVO:67985807 Keywords : strongly dense matrix * Boolean matrix * nonnegative matrix * idempotent matrix * intrinsic product * generalized complementary basic matrix Subject RIV: BA - General Mathematics

  15. Strongly 2-connected orientations of graphs

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2014-01-01

    We prove that a graph admits a strongly 2-connected orientation if and only if it is 4-edge-connected, and every vertex-deleted subgraph is 2-edge-connected. In particular, every 4-connected graph has such an orientation while no cubic 3-connected graph has such an orientation....

  16. The Shape of Strongly Disturbed Dayside Magnetopause

    Directory of Open Access Journals (Sweden)

    Alexei V. Dmitriev Alla V. Suvorova

    2013-01-01

    Full Text Available During strong geomagnetic disturbances, the Earth¡¦s magnetosphere exhibits unusual and nonlinear interaction with the incident flow of magnetized solar wind plasma. Global Magneto-hydro-dynamic (MHD modeling of the magnetosphere predicts that the storm-time effects at the magnetopause result from the abnormal plasma transport and/or extremely strong field aligned currents. In-situ observations of the magnetospheric boundary, magnetopause, by Geosynchronous Operational Environmental Satellite (GOES allowed us to find experimentally such effects as a saturation of the dayside reconnection, unusual bluntness and prominent duskward skewing of the nose magnetopause. The saturation and duskward skewing were attributed to the storm-time magnetopause formation under strong southward interplanetary magnetic field (IMF. The unusual bluntness was observed during both high solar wind pressure and strong southward IMF. We suggest that these phenomena are caused by a substantial contribution of the cross-tail current magnetic field and the hot magnetospheric plasma from the asymmetrical ring current into the pressure balance at the dayside magnetopause.

  17. Solubility of apatite in H2O-NaCl and silicate-bearing solutions at 0.7-3.0 GPa, 800° C

    Science.gov (United States)

    Antignano, A.; Manning, C. E.

    2004-12-01

    Apatite is a major reservoir for the rare-earth elements (REE) in the earth's crust. However, little is known about its solubility in metamorphic fluids. We measured the solubility of apatite in H2O-NaCl and silicate bearing fluids at 800° C and 1.0-2.0 GPa using a piston-cylinder apparatus with NaCl-graphite furnaces. A single Durango fluor-apatite crystal was loaded into a 1.6 mm OD Pt inner capsule, which was crimped and then placed in a 3.5 OD Pt outer capsule with ultra pure H2O and NaCl or powdered albite. Solubility was determined by the weight loss of the apatite grain after 24 hrs. In the H2O-NaCl experiments, total dissolved solids (TDS) were initially below detection (0.4 millimolal) between XNaCl= 0 and XNaCl= 0.025. At XNaCl= 0.035, solubility was 3.3(0.2) millimolal (errors are 1s), and it increased to 57.5(0.4) millimolal at XNaCl= 0.526. Our results show that there is an enhancement in apatite solubility with increasing pressure in pure H2O. Solubility is initially below detection at bearing solutions. This probably explains textures in which monazite mantles apatite, which are common in granulite metamorphic terranes, such as the Kiirunavaara magnetite-apatite ore.

  18. A new diamond anvil cell for hydrothermal studies to 2.5 GPa and from -190 to 1200 °C

    Science.gov (United States)

    Bassett, William A.; Shen, A.H.; Bucknum, M.; Chou, I.-Ming

    1993-01-01

    A new style of diamond anvil cell(DAC) has been designed and built for conducting research in fluids at pressures to 2.5 GPa and temperatures from −190 to 1200 °C. The new DAC has been used for optical microscope observations and synchrotron x‐ray diffraction studies. Fringes produced by interference of laser light reflected from top and bottom anvil faces and from top and bottom sample faces provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in samples that have resulted from transitions and reactions. X‐ray diffraction patterns of samples under hydrothermal conditions have been made by the energy dispersive method using synchrotron radiation. The new DAC has individual heaters and individual thermocouples for the upper and lower anvils that can be controlled and can maintain temperatures with an accuracy of ±0.5 °C. Low temperatures are achieved by introducing liquid nitrogen directly into the DAC. The equation of state of H2O and the α‐β quartz transition are used to determine pressure with an accuracy of ±1% in the aqueous samples. The new DAC has been used to redetermine five isochores of H2O as well as the dehydration curves of brucite, Mg(OH)2, and muscovite, KAl2(Si3Al)O10(OH)2.

  19. A new diamond anvil cell for hydrothermal studies to 2.5 GPa and from -190 to 1200 °C

    Science.gov (United States)

    Bassett, W. A.; Shen, A. H.; Bucknum, M.; Chou, I.-Ming

    1993-08-01

    A new style of diamond anvil cell (DAC) has been designed and built for conducting research in fluids at pressures to 2.5 GPa and temperatures from -190 to 1200 °C. The new DAC has been used for optical microscope observations and synchrotron x-ray diffraction studies. Fringes produced by interference of laser light reflected from top and bottom anvil faces and from top and bottom sample faces provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in samples that have resulted from transitions and reactions. X-ray diffraction patterns of samples under hydrothermal conditions have been made by the energy dispersive method using synchrotron radiation. The new DAC has individual heaters and individual thermocouples for the upper and lower anvils that can be controlled and can maintain temperatures with an accuracy of ±0.5 °C. Low temperatures are achieved by introducing liquid nitrogen directly into the DAC. The equation of state of H2O and the α-β quartz transition are used to determine pressure with an accuracy of ±1% in the aqueous samples. The new DAC has been used to redetermine five isochores of H2O as well as the dehydration curves of brucite, Mg(OH)2, and muscovite, KAl2(Si3Al)O10(OH)2.

  20. The results of pre-design studies on the development of a new design of gas turbine compressor package of GPA-C-16 type

    Science.gov (United States)

    Smirnov, A. V.; Chobenko, V. M.; Shcherbakov, O. M.; Ushakov, S. M.; Parafiynyk, V. P.; Sereda, R. M.

    2017-08-01

    The article summarizes the results of analysis of data concerning the operation of turbocompressor packages at compressor stations for the natural gas transmission system of Ukraine. The basic requirements for gas turbine compressor packages used for modernization and reconstruction of compressor stations are considered. Using a 16 MW gas turbine package GPA-C-16S/76-1,44M1 as an example, the results of pre-design studies and some technical solutions that improve the energy efficiency of gas turbine compressor packages and their reliability, as well as its environmental performance are given. In particular, the article deals with the matching of performance characteristics of a centrifugal compressor (hereinafter compressor) and gas turbine drive to reduce fuel gas consumption; as well as application of energy efficient technologies, in particular, exhaust gas heat recovery units and gas-oil heat exchangers in turbocompressor packages oil system; as well as reducing emissions of carbon monoxide into the atmosphere using a catalytic exhaust system. Described technical solutions can be used for development of other types of gas turbine compressor packages.

  1. Nonmagnetic high pressure cell for magnetic remanence measurements up to 1.5 GPa in a superconducting quantum interference device magnetometer.

    Science.gov (United States)

    Sadykov, Ravil A; Bezaeva, Natalia S; Kharkovskiy, Alexander I; Rochette, Pierre; Gattacceca, Jérome; Trukhin, Vladimir I

    2008-11-01

    We describe here a compact nonmagnetic composite high pressure cell of piston-cylinder type with inner diameter of 6 mm equipped with manganin pressure sensor. This cell was developed for room temperature measurements of magnetic remanence of relatively large rock samples (up to 5.8 mm in diameter and 15 mm long cylinders) under hydrostatic pressure up to 1.5 GPa (the operating pressure limit) in the 2G Enterprises superconducting quantum interference device magnetometer. Its design was focused on minimizing the remanent magnetic moment m(r) of the cell (m(r)=3 x 10(-8) A m(2)) that allowed direct measurements of remanent magnetic moment M(r) under pressure for weakly magnetic materials-rock samples (M(r) epsilon[5 x 10(-7),10(-4)] A m(2)). The inner part of this composite cell is made of hard "Russian alloy" (Ni(57)Cr(40)Al(3)) whereas the envelope of the cell corps is made of less magnetic titanium alloy. This design solution permitted to reduce the total remanent magnetic moment of the whole cell and represents the main device feature. We describe here the choice of materials for pressure cell based on their magnetic and mechanical properties, the choice of the pressure transmitting medium (polyethilsiloxane liquid) providing perfectly hydrostatic conditions for the sample as well as the cell geometry. The cell performance is illustrated by results of pressure demagnetization experiments on rocks and minerals.

  2. Confinement and αs in a strong magnetic field

    Directory of Open Access Journals (Sweden)

    Yu.A. Simonov

    2015-07-01

    Full Text Available Hadron decay widths are shown to increase in strong magnetic fields as Γ(eB∼eBκΓ(0. The same mechanism is shown to be present in the production of the sea quark pair inside the confining string, which decreases the string tension with the growing eB parallel to the string. On the other hand, the average energy of the qq¯ holes in the string world sheet increases, when the direction of B is perpendicular to the sheet. These two effects stipulate the spectacular picture of the B dependent confinement and αs, discovered on the lattice.

  3. Strongly interacting atom lasers in three-dimensional optical lattices.

    Science.gov (United States)

    Hen, Itay; Rigol, Marcos

    2010-10-29

    We show that the dynamical melting of a Mott insulator in a three-dimensional lattice leads to condensation at nonzero momenta, a phenomenon that can be used to generate strongly interacting atom lasers in optical lattices. For infinite on-site repulsion, the case considered here, the momenta at which bosons condense are determined analytically and found to have a simple dependence on the hopping amplitudes. The occupation of the condensates is shown to scale linearly with the total number of atoms in the initial Mott insulator. Our results are obtained by using a Gutzwiller-type mean-field approach, gauged against exact-diagonalization solutions of small systems.

  4. Strong dynamical effects during stick-slip adhesive peeling.

    Science.gov (United States)

    Dalbe, Marie-Julie; Santucci, Stéphane; Cortet, Pierre-Philippe; Vanel, Loïc

    2014-01-07

    We consider the classical problem of the stick-slip dynamics observed when peeling a roller adhesive tape at a constant velocity. From fast imaging recordings, we extract the dependence of the stick and slip phase durations on the imposed peeling velocity and peeled ribbon length. Predictions of Maugis and Barquins [in Adhesion 12, edited by K. W. Allen, Elsevier ASP, London, 1988, pp. 205-222] based on a quasistatic assumption succeed to describe quantitatively our measurements of the stick phase duration. Such a model however fails to predict the full stick-slip cycle duration, revealing strong dynamical effects during the slip phase.

  5. Inelastic electron scattering influence on the strong coupling oxide superconductors

    International Nuclear Information System (INIS)

    Gabovich, A.M.; Voitenko, A.I.

    1995-01-01

    The superconducting order parameters Δ and energy gap Δ g are calculated taking into account the pair-breaking inelastic quasiparticle scattering by thermal Bose-excitations, e.g., phonons. The treatment is self-consistent because the scattering amplitude depends on Δ. The superconducting transition for any strength of the inelastic scattering is the phase transition of the first kind and the dependences Δ (T) and Δ g (T) tend to rectangular curve that agrees well with the experiment for high-Tc oxides. On the basis of the developed theory the nuclear spin-lattice relaxation rate R s in the superconducting state is calculated. The Hebel-Slichter peak in R s (T) is shown to disappear for strong enough inelastic scattering

  6. Coherence and quasistable states in a strong infrared field

    Science.gov (United States)

    Zhong, Changchun; Robicheaux, F.

    2016-03-01

    We study the quasistability of UV-pulse-train-excited H atoms in a strong infrared (IR) laser as a function of the phase delay of the UV pulse train relative to the IR laser. The UV pulse train contains two frequency components. When the two components have frequencies separated by two IR photons, the population of surviving electrons is modulated by up to ten percent. When electrons are excited to right above or below the threshold, the survival probabilities have inverted phase delay dependence, which can be explained classically. When the two frequencies are one IR photon apart, the angular symmetry of the quasistable electrons is broken, and the asymmetry is also controlled by the phase delay. The asymmetrical distribution can be observed while the IR is on and smoothly evolves to a nonzero asymmetry that only weakly depends on the duration of the IR field.

  7. Large linear magnetoresistivity in strongly inhomogeneous planar and layered systems

    International Nuclear Information System (INIS)

    Bulgadaev, S.A.; Kusmartsev, F.V.

    2005-01-01

    Explicit expressions for magnetoresistance R of planar and layered strongly inhomogeneous two-phase systems are obtained, using exact dual transformation, connecting effective conductivities of in-plane isotropic two-phase systems with and without magnetic field. These expressions allow to describe the magnetoresistance of various inhomogeneous media at arbitrary concentrations x and magnetic fields H. All expressions show large linear magnetoresistance effect with different dependencies on the phase concentrations. The corresponding plots of the x- and H-dependencies of R(x,H) are represented for various values, respectively, of magnetic field and concentrations at some values of inhomogeneity parameter. The obtained results show a remarkable similarity with the existing experimental data on linear magnetoresistance in silver chalcogenides Ag 2+δ Se. A possible physical explanation of this similarity is proposed. It is shown that the random, stripe type, structures of inhomogeneities are the most suitable for a fabrication of magnetic sensors and a storage of information at room temperatures

  8. Dependent failures of diesel generators

    International Nuclear Information System (INIS)

    Mankamo, T.; Pulkkinen, U.

    1982-01-01

    This survey of dependent failures (common-cause failures) is based on the data of diesel generator failures in U. S. nuclear power plants as reported in Licensee Event Reports. Failures were classified into random and potentially dependent failures. All failures due to design errors, manufacturing or installation errors, maintenance errors, or deviations in the operational environment were classified as potentially dependent failures.The statistical dependence between failures was estimated from the relative portion of multiple failures. Results confirm the earlier view of the significance of statistical dependence, a strong dependence on the age of the diesel generator was found in each failure class excluding random failures and maintenance errors, which had a nearly constant frequency independent of diesel generator age

  9. Strong electroactive biodegradable shape memory polymer networks based on star-shaped polylactide and aniline trimer for bone tissue engineering.

    Science.gov (United States)

    Xie, Meihua; Wang, Ling; Ge, Juan; Guo, Baolin; Ma, Peter X

    2015-04-01

    Preparation of functional shape memory polymer (SMP) for tissue engineering remains a challenge. Here the synthesis of strong electroactive shape memory polymer (ESMP) networks based on star-shaped polylactide (PLA) and aniline trimer (AT) is reported. Six-armed PLAs with various chain lengths were chemically cross-linked to synthesize SMP. After addition of an electroactive AT segment into the SMP, ESMP was obtained. The polymers were characterized by (1)H NMR, GPC, FT-IR, CV, DSC, DMA, tensile test, and degradation test. The SMP and ESMP exhibited strong mechanical properties (modulus higher than GPa) and excellent shape memory performance: short recovery time (several seconds), high recovery ratio (over 94%), and high fixity ratio (almost 100%). Moreover, cyclic voltammetry test confirmed the electroactivity of the ESMP. The ESMP significantly enhanced the proliferation of C2C12 cells compared to SMP and linear PLA (control). In addition, the ESMP greatly improved the osteogenic differentiation of C2C12 myoblast cells compared to PH10 and PLA in terms of ALP enzyme activity, immunofluorescence staining, and relative gene expression by quantitative real-time polymerase chain reaction (qRT-PCR). These intelligent SMPs and electroactive SMP with strong mechanical properties, tunable degradability, good electroactivity, biocompatibility, and enhanced osteogenic differentiation of C2C12 cells show great potential for bone regeneration.

  10. Strong ground motion prediction using virtual earthquakes.

    Science.gov (United States)

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  11. Gallstone ileus resulting in strong intestinal obstruction

    Directory of Open Access Journals (Sweden)

    Israel Szajnbok

    Full Text Available Mechanic intestinal obstruction, caused by the passage of biliary calculus from vesicle to intestine, through fistulization, although not frequent, deserve study due to the morbi-mortality rates. Incidence in elder people explains the association with chronic degenerative diseases, increasing complexity in terms of therapy decision. Literature discusses the need and opportunity for the one or two-phase surgical attack of the cholecystenteric fistule, in front of the resolution on the obstructive urgency and makes reference to Gallstone Ileus as an exception for strong intestinal obstruction. The more frequent intestinal obstruction observed is when it occurs a Gallstone Ileus impacting in terms of ileocecal valve. The authors submit a Gallstone Ileus manifestation as causing strong intestinal obstruction, discussing aspects regarding diagnostic and treatment.

  12. Strong gauge boson scattering at the LHC

    CERN Document Server

    Rindani, S.D.

    2009-01-01

    In the standard model with electroweak symmetry breaking through the Higgs mechanism, electroweak gauge-boson scattering amplitudes are large if the Higgs boson is heavy, and electroweak gauge interactions become strong. In theories with electroweak symmetry breaking through alternative mechanisms, there could be a strongly interacting gauge sector, possibly with resonances in an accessible energy region. In general, the scattering of longitudinally polarized massive gauge bosons can give information on the mechanism of spontaneous symmetry breaking. At energies below the symmetry breaking scale, the equivalence theorem relates the scattering amplitudes to those of the "would-be" Goldstone modes. In the absence of Higgs bosons, unitarity would be restored by some new physics which can be studied through WW scattering. Some representatives models are discussed. Isolating WW scattering at a hadron collider from other contributions involving W emission from parton lines needs a good understanding of the backgrou...

  13. Strong spin-photon coupling in silicon.

    Science.gov (United States)

    Samkharadze, N; Zheng, G; Kalhor, N; Brousse, D; Sammak, A; Mendes, U C; Blais, A; Scappucci, G; Vandersypen, L M K

    2018-03-09

    Long coherence times of single spins in silicon quantum dots make these systems highly attractive for quantum computation, but how to scale up spin qubit systems remains an open question. As a first step to address this issue, we demonstrate the strong coupling of a single electron spin and a single microwave photon. The electron spin is trapped in a silicon double quantum dot, and the microwave photon is stored in an on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a strong local magnetic field gradient from a nearby micromagnet. Our results provide a route to realizing large networks of quantum dot-based spin qubit registers. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  14. Cosmogenic photons strongly constrain UHECR source models

    Directory of Open Access Journals (Sweden)

    van Vliet Arjen

    2017-01-01

    Full Text Available With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT’s IGRB, as long as their number density is not strongly peaked at recent times.

  15. Waves in strong centrifugal fields: dissipationless gas

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2015-04-01

    Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

  16. Quantum strongly secure ramp secret sharing

    DEFF Research Database (Denmark)

    Zhang, Paul; Matsumoto, Rytaro Yamashita

    2015-01-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together...... however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced....... This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can...

  17. Quantum Transport in Strongly Correlated Systems

    DEFF Research Database (Denmark)

    Bohr, Dan

    2007-01-01

    the density matrix renormalization group (DMRG) method. We present two DMRG setups for calculating the linear conductance of strongly correlated nanostructures in the infinitesimal source-drain voltage regime. The first setup describes the leads by modified real-space tight-binding chains, whereas the second...... screening plays a much less significant role than in bulk systems due to the reduced size of the objects, therefore making it necessary to consider the importance of correlations between electrons. The work presented in this thesis deals with quantum transport through strongly correlated systems using....... Thus both coherence and correlation effects are important in this model, and the methods applied should be able to handle both these effects rigorously. We present the DMRG setup for this model and benchmark against existing Greens function results for the model. Then we present initial DMRG results...

  18. Hydrogen atoms in a strong magnetic field

    International Nuclear Information System (INIS)

    Santos, R.R. dos.

    1975-07-01

    The energies and wave functions of the 14 lowest states of a Hydrogen atom in a strong magnetic field are calculated, using a variational scheme. The equivalence between the atomic problem and the problems related with excitons and impurities in semiconductors in the presence of a strong magnetic field are shown. The calculations of the energies and wave functions have been divided in two regions: the first, for the magnetic field ranging between zero and 10 9 G; in the second the magnetic field ranges between 10 9 and 10 11 G. The results have been compared with those obtained by previous authors. The computation time necessary for the calculations is small. Therefore this is a convenient scheme to obtain the energies and wave functions for the problem. Transition probabilities, wavelengths and oscillator strengths for some allowed transitions are also calculated. (Author) [pt

  19. Strong Josephson Coupling in Planar Graphene Junctions

    Science.gov (United States)

    Park, Jinho; Lee, Gil-Ho; Lee, Jae Hyeong; Takane, Yositake; Imura, Ken-Ichiro; Taniguchi, Takashi; Watanabe, Kenji; Lee, Hu-Jong

    A recent breakthrough of processing graphene, employing encapsulation by hexagonal boron nitride layers (BGB structure), allows realizing the ballistic carrier transport in graphene. Thereafter, ballistic Josephson coupling has been studied by closely edge-contacted BGB structure with two superconducting electrodes. Here, we report on the strong Josephson coupling with planar graphene junction in truly short and ballistic regime. Our device showed high transmission probability and the junction critical current (IC) oscillating for sweeping the gate voltage along with the normal conductance oscillation (Fabry-Perot oscillations), providing a direct evidence for the ballistic nature of the junction pair current. We also observed the convex-upward shape of decreasing critical currents with increasing temperature, canonical properties of the short Josephson coupling. By fitting these curves into theoretical models, we demonstrate the strong Josephson coupling in our devices, which is also supported by the exceptionally large value of ICRN ( 2 Δ / e RNis the normal resistance).

  20. Electroweak and Strong Interactions Phenomenology, Concepts, Models

    CERN Document Server

    Scheck, Florian

    2012-01-01

    Electroweak and Strong Interaction: Phenomenology, Concepts, Models, begins with relativistic quantum mechanics and some quantum field theory which lay the foundation for the rest of the text. The phenomenology and the physics of the fundamental interactions are emphasized through a detailed discussion of the empirical fundamentals of unified theories of strong, electromagnetic, and weak interactions. The principles of local gauge theories are described both in a heuristic and a geometric framework. The minimal standard model of the fundamental interactions is developed in detail and characteristic applications are worked out. Possible signals of physics beyond that model, notably in the physics of neutrinos are also discussed. Among the applications scattering on nucleons and on nuclei provide salient examples. Numerous exercises with solutions make the text suitable for advanced courses or individual study. This completely updated revised new edition contains an enlarged chapter on quantum chromodynamics an...

  1. Frictional Coulomb drag in strong magnetic fields

    DEFF Research Database (Denmark)

    Bønsager, Martin Christian; Flensberg, Karsten; Hu, Ben Yu-Kuang

    1997-01-01

    A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21......) is evaluated using diagrammatic techniques. The transresistivity is given by an integral over energy and momentum transfer weighted by the product of the screened interlayer interaction and the phase space for scattering events. We demonstrate, by a numerical analysis of the transresistivity, that for well...

  2. Orbits in weak and strong bars

    CERN Document Server

    Contopoulos, George

    1980-01-01

    The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).

  3. Strong sum distance in fuzzy graphs.

    Science.gov (United States)

    Tom, Mini; Sunitha, Muraleedharan Shetty

    2015-01-01

    In this paper the idea of strong sum distance which is a metric, in a fuzzy graph is introduced. Based on this metric the concepts of eccentricity, radius, diameter, center and self centered fuzzy graphs are studied. Some properties of eccentric nodes, peripheral nodes and central nodes are obtained. A characterisation of self centered complete fuzzy graph is obtained and conditions under which a fuzzy cycle is self centered are established. We have proved that based on this metric, an eccentric node of a fuzzy tree G is a fuzzy end node of G and a node is an eccentric node of a fuzzy tree if and only if it is a peripheral node of G and the center of a fuzzy tree consists of either one or two neighboring nodes. The concepts of boundary nodes and interior nodes in a fuzzy graph based on strong sum distance are introduced. Some properties of boundary nodes, interior nodes and complete nodes are studied.

  4. Analytical solution of strongly nonlinear Duffing oscillators

    Directory of Open Access Journals (Sweden)

    A.M. El-Naggar

    2016-06-01

    Full Text Available In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε is defined such that the value of α is always small regardless of the magnitude of the original parameter ε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to α. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.

  5. SUSY strong production (leptonic) with ATLAS

    CERN Document Server

    Saito, Tomoyuki; The ATLAS collaboration

    2017-01-01

    Supersymmetry is one of the most motivated scenarios for physics beyond the Standard Model. This article summarizes recent ATLAS results on searches for supersymmetry in proton-proton collisions at a centre-of-mass energy of 13 TeV at LHC, which target supersymmetric particles produced by strong interaction in events with leptonic fi nal states. No signi ficant excess above the Standard Model expectation is observed and exclusion limits have been set on squark and gluino masses in various scenarios.

  6. Strong coupling QED with two fermionic flavors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K.C.

    1990-11-01

    We report the recent results of our simulation of strong coupling QED, with non-compact action, on lattices 10{sup 4} and 16{sup 4}. Since we are dealing with two staggered fermionic flavors, we use hybrid algorithm to do the simulation. In addition to the measurement of the chiral order parameter {l angle}{bar {psi}}{psi}{r angle}, we also measure magnetic monopole susceptibility, {chi}, throughout the region of chiral transition. 6 refs., 6 figs.

  7. Magnetic properties of strongly asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Kutschera, M.; Wojcik, W.

    1988-01-01

    We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)

  8. Strong coupling analogue of the Born series

    International Nuclear Information System (INIS)

    Dolinszky, T.

    1989-10-01

    In a given partial wave, the strength of the centrifugal term to be incorporated into the WKBA solutions in different spatial regions can be adjusted so as to make the first order wave functions everywhere smooth and, in strong coupling, exactly reproduce Quantum Mechanics throughout the space. The relevant higher order approximations supply an absolute convergent series expansion of the exact scattering state. (author) 4 refs.; 2 figs.; 2 tabs

  9. Strong-Q-sequences and small d

    Czech Academy of Sciences Publication Activity Database

    Chodounský, David

    2012-01-01

    Roč. 159, č. 3 (2012), s. 2942-2946 ISSN 0166-8641. [Prague Symposium on General Topology and its Relations to Modern Analysis and Algebra /11./. Prague, 07.08.2011-12.08.2011] Institutional support: RVO:67985840 Keywords : Katowice problem * strong-Q-sequence * dominating number Subject RIV: BA - General Mathematics Impact factor: 0.562, year: 2012 http://www.sciencedirect.com/science/article/pii/S0166864112002222

  10. Strong decays of nonstrange q3 baryons

    International Nuclear Information System (INIS)

    Bijker, R.; Iachello, F.; Leviatan, A.

    1997-01-01

    We study strong decays of nonstrange baryons by making use of the algebraic approach to hadron structure. Within this framework we derive closed expressions for decay widths in an elementary-meson emission model and use these to analyze the experimental data for N * →N+π, N * →Δ+π, N * →N+η, Δ * →N+π, Δ * →Δ+π, and Δ * →Δ+η decays. copyright 1997 The American Physical Society

  11. Simulation of turbulent flows containing strong shocks

    Science.gov (United States)

    Fryxell, Bruce; Menon, Suresh

    2008-12-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  12. Strong CP, flavor, and twisted split fermions

    International Nuclear Information System (INIS)

    Harnik, Roni; Perez, Gilad; Schwartz, Matthew D.; Shirman, Yuri

    2005-01-01

    We present a natural solution to the strong CP problem in the context of split fermions. By assuming CP is spontaneously broken in the bulk, a weak CKM phase is created in the standard model due to a twisting in flavor space of the bulk fermion wavefunctions. But the strong CP phase remains zero, being essentially protected by parity in the bulk and CP on the branes. As always in models of spontaneous CP breaking, radiative corrections to theta bar from the standard model are tiny, but even higher dimension operators are not that dangerous. The twisting phenomenon was recently shown to be generic, and not to interfere with the way that split fermions naturally weaves small numbers into the standard model. It follows that out approach to strong CP is compatible with flavor, and we sketch a comprehensive model. We also look at deconstructed version of this setup which provides a viable 4D model of spontaneous CP breaking which is not in the Nelson-Barr class. (author)

  13. Transport phenomena in strongly correlated Fermi liquids

    Energy Technology Data Exchange (ETDEWEB)

    Kontani, Hiroshi [Nagoya Univ., Aichi (Japan). Dept. of Physics

    2013-03-01

    Comprehensive overview. Written by an expert of this topic. Provides the reader with current developments in the field. In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, {tau}, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical point using a uniform approach. We also discuss spin related transport phenomena in strongly correlated systems. In many d- and f-electron systems, the spin current induced by the spin Hall effect is considerably greater because of the orbital degrees of freedom. This fact attracts much attention due to its potential application in spintronics. We discuss various novel charge, spin and heat transport phenomena in strongly correlated metals.

  14. Simulation of turbulent flows containing strong shocks

    International Nuclear Information System (INIS)

    Fryxell, Bruce; Menon, Suresh

    2008-01-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  15. Strong association between corticosterone levels and temperature-dependent metabolic rate in individual zebra finches

    NARCIS (Netherlands)

    Jimeno Revilla, Blanca; Hau, Michaela; Verhulst, Simon

    2017-01-01

    Glucocorticoid hormones (GCs) are often assumed to be indicators of stress. At the same time, one of their fundamental roles is to facilitate metabolic processes to accommodate changes in energetic demands. Although the metabolic function of GCs is thought to be ubiquitous across vertebrates, we are

  16. Ascaroside expression in Caenorhabditis elegans is strongly dependent on diet and developmental stage

    Science.gov (United States)

    A group of small signaling molecules called ascarosides, associated with dauer formation, male attraction and social behavior in the nematode Caenorhabditis elegans, are shown to be regulated by developmental stage and environmental factors. The concentration of dauer-inducing ascaroside, ascr#2, i...

  17. Atomic structure dependence of nonsequential double ionization of He, Ne and Ar in strong laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, V L B de; Feuerstein, B; Zrost, K; Fischer, D; Rudenko, A; Afaneh, F; Schroeter, C D; Moshammer, R; Ullrich, J [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany)

    2004-04-28

    The ion momentum spectra for nonsequential double ionization of rare gases (He, Ne and Ar) in 23 fs 795 nm laser pulses were measured in the intensity range 0.075-1.25 PW cm{sup -2}. In the studies published, confusing differences in the shape of momentum distributions among different targets are consistently explained within a recollision scenario: excitation during recollision plus subsequent field ionization, not implemented in most theoretical approaches, evidently plays a decisive role for He and Ar nonsequential double ionization whereas it plays only a minor role for Ne. (letter to the editor)

  18. Efficacy of melody-based aphasia therapy may strongly depend on rhythm and conversational speech formulas

    OpenAIRE

    Benjamin Stahl

    2014-01-01

    Left-hemisphere stroke patients suffering from language and speech disorders are often able to sing entire pieces of text fluently. This finding has inspired a number of melody-based rehabilitation programs – most notable among them a treatment known as Melodic Intonation Therapy – as well as two fundamental research questions. When the experimental design focuses on one point in time (cross section), one may determine whether or not singing has an immediate effect on syllable production in p...

  19. Efficacy of melody-based aphasia therapy may strongly depend on rhythm and conversational speech formulas

    Directory of Open Access Journals (Sweden)

    Benjamin Stahl

    2014-04-01

    Full Text Available Left-hemisphere stroke patients suffering from language and speech disorders are often able to sing entire pieces of text fluently. This finding has inspired a number of melody-based rehabilitation programs – most notable among them a treatment known as Melodic Intonation Therapy – as well as two fundamental research questions. When the experimental design focuses on one point in time (cross section, one may determine whether or not singing has an immediate effect on syllable production in patients with language and speech disorders. When the design focuses on changes over several points in time (longitudinal section, one may gain insight as to whether or not singing has a long-term effect on language and speech recovery. The current work addresses both of these questions with two separate experiments that investigate the interplay of melody, rhythm and lyric type in 32 patients with non-fluent aphasia and apraxia of speech (Stahl et al., 2011; Stahl et al., 2013. Taken together, the experiments deliver three main results. First, singing and rhythmic pacing proved to be equally effective in facilitating immediate syllable production and long-term language and speech recovery. Controlling for various influences such as prosody, syllable duration and phonetic complexity, the data did not reveal any advantage of singing over rhythmic speech. This result was independent of lesion size and lesion location in the patients. Second, patients with extensive left-sided basal ganglia lesions produced more correct syllables when their speech was paced by rhythmic drumbeats. This observation is consistent with the idea that regular auditory cues may partially compensate for corticostriatal damage and thereby improve speech-motor planning (Grahn & Watson, 2013. Third, conversational speech formulas and well-known song lyrics yielded higher rates of correct syllable production than novel word sequences – whether patients were singing or speaking rhythmically. Moreover, the training of conversational speech formulas led to long-term progress in the production of formulaic language. The patients were able to establish their own individual formulaic repertoire in order to communicate some basic needs in daily life. This finding may result from the fact that, according to present knowledge, the production of formulaic language engages bilateral neural networks including right frontotemporal areas, the right basal ganglia and, possibly, the right cerebellum (Hughlings-Jackson, 1878; Speedie et al., 1993; Ackermann et al., 1998; Van Lancker Sidtis & Postman, 2006; Sidtis et al., 2009. In other words, left-hemisphere stroke patients may use right-hemisphere language resources to produce conversational speech formulas, whether they are sung or rhythmically spoken. In conclusion, the current experiments highlight the critical role of rhythm and conversational speech formulas in melody-based aphasia therapy.

  20. Block of nicotinic acetylcholine receptors by philanthotoxins is strongly dependent on their subunit composition

    DEFF Research Database (Denmark)

    Kachel, Hamid S; Patel, Rohit N; Franzyk, Henrik

    2016-01-01

    Philanthotoxin-433 (PhTX-433) is an active component of the venom from the Egyptian digger wasp, Philanthus triangulum. PhTX-433 inhibits several excitatory ligand-gated ion channels, and to improve selectivity two synthetic analogues, PhTX-343 and PhTX-12, were developed. Previous work showed a ...