Comments on "Adaptive resolution simulation in equilibrium and beyond" by H. Wang and A. Agarwal

NASA Astrophysics Data System (ADS)

Klein, R.

2015-09-01

Wang and Agarwal (Eur. Phys. J. Special Topics, this issue, 2015, doi: 10.1140/epjst/e2015-02411-2) discuss variants of Adaptive Resolution Molecular Dynamics Simulations (AdResS), and their applications. Here we comment on their report, addressing scaling properties of the method, artificial forcings implemented to ensure constant density across the full simulation despite changing thermodynamic properties of the simulated media, the possible relation between an AdResS system on the one hand and a phase transition phenomenon on the other, and peculiarities of the SPC/E water model.

Corrigendum to "Performance study of a large 1 × 1 m2 MRPC with 1 × 1 cm2 readout pads" [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 113-117

NASA Astrophysics Data System (ADS)

Carnesecchi, F.; Liu, Z.; Kim, D. W.; Rodriguez, O. M.; Park, W.; Vallecorsa, S.; Williams, M. C. S.; Zichichi, A.; Zuyeuski, R.

2018-02-01

The authors regret that 3 authors were missed out in the original article and there is a modification to the Acknowledgements section. The corrected author group information and Acknowledgements is as follows:

The Antiaircraft Journal. Volume 92, Number 5, September-October 1949

DTIC Science & Technology

1949-10-01

philosophical reflections on the subject of po’werand those to whom it should be entrusted. Recall the words of much-studied Machiavelli , than whom...Leavenworth. Kan. Rauch. A. R, Comm. of Basic Phys. Sc.• Res. & Dev. Board, Pentagon. \\Vash. 25. D. C. Rawls . J. W., Jr.. AFF Liaison Off.. Boeing Aircraft

Study of VUV Generation by Coherent Resonant Frequency Mixing in Metal Vapors.

DTIC Science & Technology

1986-04-24

measuroments of coherent two- dye-laser oscillator -2 mplifier system designed for ex- photon aborption in lithium demonstrate that this periments t res(ona-nt...Harmonic Vacuum-Ultraviolet Generation in Metal Vapors," Phys. Rev. A 19, 1589 (1979). 2. ,.-C. Diels. E. W. Van Strvhand. and D. Gold , in Picosecond

Partial entropic stabilization of lattice Boltzmann magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Flint, Christopher; Vahala, George

2018-01-01

The entropic lattice Boltzmann algorithm of Karlin et al. [Phys. Rev. E 90, 031302 (2014), 10.1103/PhysRevE.90.031302] is partially extended to magnetohydrodynamics, based on the Dellar model of introducing a vector distribution for the magnetic field. This entropic ansatz is now applied only to the scalar particle distribution function so as to permit the many problems entailing magnetic field reversal. A 9-bit lattice is employed for both particle and magnetic distributions for our two-dimensional simulations. The entropic ansatz is benchmarked against our earlier multiple relaxation lattice-Boltzmann model for the Kelvin-Helmholtz instability in a magnetized jet. Other two-dimensional simulations are performed and compared to results determined by more standard direct algorithms: in particular the switch over between the Kelvin-Helmholtz or tearing mode instability of Chen et al. [J. Geophys. Res.: Space Phys. 102, 151 (1997), 10.1029/96JA03144], and the generalized Orszag-Tang vortex model of Biskamp-Welter [Phys. Fluids B 1, 1964 (1989), 10.1063/1.859060]. Very good results are achieved.

Laser Spectroscopic Study on Oxygen Isotope Effects in Ozone Surface Decomposition

NASA Astrophysics Data System (ADS)

Minissale, Marco; Boursier, Corinne; Elandaloussi, Hadj; Te, Yao; Jeseck, Pascal; Rouille, Christian; Zanon-Willette, Thomas; Janssen, Christof

2016-04-01

The isotope kinetics of ozone formation in the Chapman reaction [1] O + O2 + M → O3 + M (1) provides the primary example for a chemically induced oxygen isotope anomaly and is associated with large [2] and mass independent [3] oxygen isotope enrichments in the product molecule, linked to a symmetry selection in the ozone formation kinetics [4-5]. The isotopic composition of ozone and its transfer to other molecules is a powerful tracer in the atmospheric and biogeochemical sciences [6] and serves as a primary model for a possible explanation of the oxygen isotopic heterogeneity in the Solar system [7-8]. Recently, the isotope fractionation in the photolytic decomposition process O3 + hν → O2 + O (2) using visible light has been studied in detail [9-10]. Much less is currently known about the isotope fractionation in the dry deposition or in the gas phase thermal decomposition of ozone O3 + M → O2 + O +M. (3) Here we report on first spectroscopic studies of non-photolytic ozone decomposition using a cw-quantum cascade laser at 9.5 μm. The concentration of individual ozone isotopomers (16O3,16O16O17O, and 16O17O16O) in a teflon coated reaction cell is followed in real time at temperatures between 25 and 150 °C. Observed ozone decay rates depend on homogeneous (reaction (3)) processes in the gas phase and on heterogeneous reactions on the wall. A preliminary analysis reveals agreement with currently recommended ozone decay rates in the gas phase and the absence of a large symmetry selection in the surface decomposition process, indicating the absence of a mass independent fractionation effect. This result is in agreement with previous mass spectrometer (MS) studies on heterogeneous ozone formation on pyrex [11], but contradicts an earlier MS study [12] on ozone surface decomposition on pyrex and quartz. Implications for atmospheric chemistry will be discussed. [1] Morton, J., Barnes, J., Schueler, B. and Mauersberger, K. J. Geophys. Res. 95, 901 - 907 (1990). [2] Mauersberger, K. Geophys. Res. Lett. 8, 935-937 (1981). [3] Thiemens, M. H. and Heidenreich, J. E. Science 219, 1073 - 1075 (1983). [4] Janssen, C., Guenther, J., Mauersberger, K. and Krankowsky, D. Phys. Chem. Chem. Phys. 3, 4718-4721 (2001). [5] Gao, Y. Q. and Marcus, R. A. Science 293, 259-263 (2001). [6] Brenninkmeijer, C. A. M. et al. Chem. Rev. 103, 5125 - 5162 (2003). [7] Thiemens, M. H. and Shaheen, in Treatise on Geochemistry, Holland H. and Turekian K. eds., 151 - 177 (2014). [8] Marcus, R. A. J. Chem. Phys. 121, 8201 - 8211 (2004). [9] Früchtl, M., Janssen, C. and Röckmann, T. J. Geophys. Res. Atmos. 120, 4398 - 4416 (2015). [10] Früchtl, M., Janssen, C., Taraborrelli, D., Gromov, S. and Röckmann, T. Geophys. Res. Lett. (2015). [11] Janssen, C. and Tuzson, B. J. Phys. Chem. A 114, 9709-9719 (2010). [12] Chakraborty, S. and Bhattacharya, S. K. Chem. Phys. Lett. 369, 662-667 (2003).

Corrigendum to "Fundamental neutron physics beamline at the spallation neutron source at ORNL" [Nucl. Instrum. Methods Phys. Res. A 773 (2015) 45-51

NASA Astrophysics Data System (ADS)

Fomin, N.; Greene, G. L.; Allen, R. R.; Cianciolo, V.; Crawford, C.; Ito, T. M.; Huffman, P. R.; Iverson, E. B.; Mahurin, R.; Snow, W. M.

2015-07-01

The authors regret that there was an error in the author list of the original publication. The name of author Dr. Ito was misspelled. The correct author list is as above. The authors would like to apologise for any inconvenience caused.

Observation-Based Dissipation and Input Terms for Spectral Wave Models, with End-User Testing

DTIC Science & Technology

2013-09-30

swell dissipation across the ocean. Geophys. Res. Lett., 36, L06607, 4p Ardhuin, F., E. Rogers, A. Babanin, J.-F. Filipot, R. Magne, A. Roland, A. van... definitions , calibration and validations. J. Phys. Oceanogr., 40, 1917-1941 Babanin, A.V., K.N. Tsagareli, I.R Young, and D.J. Walker, 2010: Numerical

Theory of relativistic radiation reflection from plasmas

NASA Astrophysics Data System (ADS)

Gonoskov, Arkady

2018-01-01

We consider the reflection of relativistically strong radiation from plasma and identify the physical origin of the electrons' tendency to form a thin sheet, which maintains its localisation throughout its motion. Thereby, we justify the principle of relativistic electronic spring (RES) proposed in [Gonoskov et al., Phys. Rev. E 84, 046403 (2011)]. Using the RES principle, we derive a closed set of differential equations that describe the reflection of radiation with arbitrary variation of polarization and intensity from plasma with an arbitrary density profile for an arbitrary angle of incidence. We confirm with ab initio PIC simulations that the developed theory accurately describes laser-plasma interactions in the regime where the reflection of relativistically strong radiation is accompanied by significant, repeated relocation of plasma electrons. In particular, the theory can be applied for the studies of plasma heating and coherent and incoherent emissions in the RES regime of high-intensity laser-plasma interaction.

Nanobridge SQUIDs as calorimetric inductive particle detectors

NASA Astrophysics Data System (ADS)

Gallop, John; Cox, David; Hao, Ling

2015-08-01

Superconducting transition edge sensors (TESs) have made dramatic progress since their invention some 65 years ago (Andrews et al 1949 Phys. Rev. 76 154-155 Irwin and Hilton 2005 Topics Appl. Phys. 99 63-149) until now there are major imaging arrays of TESs with as many as 7588 separate sensors. These are extensively used by astronomers for some ground-breaking observations (Hattori et al 2013 Nucl. Instrum. Methods Phys. Res. A 732 299-302). The great success of TES systems has tended to overshadow other superconducting sensor developments. However there are other types (Sobolewski et al 2003 IEEE Trans. Appl. Supercond. 13 1151-7 Hadfield 2009 Nat. Photonics 3 696-705) which are discussed in papers within this special edition of the journal. Here we describe a quite different type of detector, also applicable to single photon detection but possessing possible advantages (higher sensitivity, higher operating temperature) over the conventional TES, at least for single detectors.

3-D, Impulsive Magnetic Reconnection in a Laboratory Plasma (Invited)

NASA Astrophysics Data System (ADS)

Dorfman, S. E.; Ji, H.; Yamada, M.; Yoo, J.; Myers, C. E.; Roytershteyn, V.; Daughton, W. S.; Jara-Almonte, J.

2013-12-01

Magnetic reconnection is a fundamental plasma process involving the efficient conversion of magnetic field energy to plasma kinetic energy through changing field line topology. In many space and astrophysical systems, including the solar surface and the Earth's magnetotail, reconnection is not only fast, but also impulsive; in other words, a slow buildup phase is followed by a comparatively quick release of magnetic energy. An important question in the literature is if these examples of impulsive reconnection can be described by a two-dimensional model with no variation in the out-of-plane direction or if impulsive reconnection is fundamentally three-dimensional. Events observed on the Magnetic Reconnection Experiment (MRX) are characterized by large local gradients in the third direction and cannot be explained by 2-D models [1]. Detailed measurements show that the ejection of flux rope structures from the current sheet plays a key role in these events. By contrast, even though electromagnetic fluctuations in the lower hybrid frequency range are also observed concurrently with the impulsive behavior, they are not the key physics responsible. Furthermore, an important discrepancy in the layer width and force balance between the collisionless regime of MRX and kinetic simulations [2-4] persists when the fluctuations are small or absent, implying that they are not the cause of the wider electron layers observed in the experiment [5]. These wider layers may instead be due to the formation of flux ropes with a wide range of sizes; consistent with this hypothesis, flux rope signatures are observed down to the smallest scales resolved by the diagnostics. Finally, a qualitative, 3-D, two-fluid model is proposed to explain the observed disruptions. Many of the features observed in MRX including current disruptions [6], flux ropes [7], and electromagnetic fluctuations [8] have analogues in space observations. Thus, further detailed comparisons may enhance our understanding of space and astrophysical plasmas where impulsive reconnection occurs. In particular, this work has relevance to the upcoming Magnetospheric Multiscale (MMS) Mission which aims to understand how electron scale structure may affect the global reconnection process. [1] S. Dorfman, et. al., Geophys. Res. Lett. 40, 233-238 (2013). [2] S. Dorfman, et. al., Phys. Plasmas 15, 102107 (2008). [3] H. Ji, et. al., Geophys. Res. Lett., 35, L13106 (2008). [4] V. Roytershteyn, et. al., Phys. Plasmas 17, 055706 (2010). [5] V. Roytershteyn, et. al., Phys. Plasmas 20, 061212 (2013). [6] S. Ohtani, et. al., J. Geophys. Res., 97(A12), 19311-19324 (1992). [7] J. P. Eastwood, et. al., J. Geophys. Res., 112, A06235 (2007). [8] J. S. Pickett, et. al., J. Geophys. Res., 106(A9), 19081-19099 (2001).

Observation of an Ultrahard Phase of Graphite Quenched from High-pressure

DTIC Science & Technology

2011-02-01

Polycrystalline NaCl at High Pressures and 300 °K. J. Geophys. Res. 1978, 83, 1257–1268. 23. Selvi , E.; Ma, Y.; Askoy, R.; Ertas, A.; White, A. High...Pressure X-ray Diffraction Study of Tungsten Disulfide. J. Phys. Chem. Solids 2006, 67, 2183–2186. 24. Askoy, R.; Ma, Y.; Selvi , E.; Chyu, M. C

Characterizing the gender gap in introductory physics

NASA Astrophysics Data System (ADS)

Kost, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

2009-06-01

Previous research [S. J. Pollock , Phys. Rev. ST Phys. Educ. Res. 3, 1 (2007)] showed that despite the use of interactive engagement techniques, the gap in performance between males and females on a conceptual learning survey persisted from pretest to post-test at the University of Colorado at Boulder. Such findings were counter to previously published work [M. Lorenzo , Am. J. Phys. 74, 118 (2006)]. This study begins by identifying a variety of other gender differences. There is a small but significant difference in the course grades of males and females. Males and females have significantly different prior understandings of physics and mathematics. Females are less likely to take high school physics than males, although they are equally likely to take high school calculus. Males and females also differ in their incoming attitudes and beliefs about physics. This collection of background factors is analyzed to determine the extent to which each factor correlates with performance on a conceptual post-test and with gender. Binned by quintiles, we observe that males and females with similar pretest scores do not have significantly different post-test scores (p>0.2) . The post-test data are then modeled using two regression models (multiple regression and logistic regression) to estimate the gender gap in post-test scores after controlling for these important prior factors. These prior factors account for about 70% of the observed gender gap. The results indicate that the gender gap exists in interactive physics classes at our institution but is largely associated with differences in previous physics and math knowledge and incoming attitudes and beliefs.

Elastic fields, dipole tensors, and interaction between self-interstitial atom defects in bcc transition metals

NASA Astrophysics Data System (ADS)

Dudarev, S. L.; Ma, Pui-Wai

2018-03-01

Density functional theory (DFT) calculations show that self-interstitial atom (SIA) defects in nonmagnetic body-centered-cubic (bcc) metals adopt strongly anisotropic configurations, elongated in the <111 > direction [S. Han et al., Phys. Rev. B 66, 220101 (2002), 10.1103/PhysRevB.66.220101; D. Nguyen-Manh et al., Phys. Rev. B 73, 020101 (2006), 10.1103/PhysRevB.73.020101; P. M. Derlet et al., Phys. Rev. B 76, 054107 (2007), 10.1103/PhysRevB.76.054107; S. L. Dudarev, Annu. Rev. Mater. Res. 43, 35 (2013), 10.1146/annurev-matsci-071312-121626]. Elastic distortions, associated with such anisotropic atomic structures, appear similar to distortions around small prismatic dislocation loops, although the extent of this similarity has never been quantified. We derive analytical formulas for the dipole tensors of SIA defects, which show that, in addition to the prismatic dislocation looplike character, the elastic field of a SIA defect also has a significant isotropic dilatation component. Using empirical potentials and DFT calculations, we parametrize dipole tensors of <111 > defects for all the nonmagnetic bcc transition metals. This enables a quantitative evaluation of the energy of elastic interaction between the defects, which also shows that in a periodic three-dimensional simple cubic arrangement of crowdions, long-range elastic interactions between a defect and all its images favor a <111 > orientation of the defect.

Modeling of a new electron-streamer acceleration mechanism

NASA Astrophysics Data System (ADS)

Ihaddadene, K. M. A.; Dwyer, J. R.; Liu, N.; Celestin, S. J.

2017-12-01

Lightning stepped leaders and laboratory spark discharges in air are known to produce X-rays [e.g., Dwyer et al., Geophys. Res. lett., 32, L20809, 2005; Kochkin et al., J. Phys. D: Appl. Phys., 45, 425202, 2012]. However, the processes behind the production of these X-rays are still not very well understood. During discharges, encounters between streamers of different polarities are very common. For example, during the formation of a new leader step, the negative streamer zone around the tip of a negative leader and the positive streamers initiated from the posiive part of a bidirectional space leader strongly interact. In laboratory experiments, when streamers are approaching a sharp electrode, streamers with the opposite polarity are initiated from the electrode and collide with the former streamers. Recently, the encounter between negative and positive streamers has been proposed as a plausible mechanism for the production of X-rays by spark discharges [Cooray et la., JASTP, 71, 1890, 2009; Kochkin et al., J. Phys. D: Appl. Phys., 45, 425202, 2012], but modeling results have shown later that the increase of the electric field involved in this process, which is above the conventional breakdown threshold field, is accompanied by a strong increase of the electron density. The resulting increase in the conductivity, in turn, causes this electric field to collapse over a few tens of picoseconds, preventing the electrons reaching high energies and producing significant X-ray emissions [e.g., Ihaddadene and Celestin, Geophys. Res. Lett., 45, 5644, 2015]. In this work, we will present simulation results of a new electron acceleration mechanism for producing runaway electron energies above hundred keV. The mechanism couples multiple single streamers and streamer head-on collisions, similar to a laboratory discharge, and is suitable for explaining the high-energy X-rays produced by discharges in air and by lightning stepped leaders.

A "Research" into International Student-Related Research: (Re)visualising Our Stand?

ERIC Educational Resources Information Center

Abdullah, Doria; Abd Aziz, Mohd Ismail; Mohd Ibrahim, Abdul Latiff

2014-01-01

This paper uses Tight ("High Educ Res Dev" 23(4):395-411, 2004; "High Educ Res Dev" 31(5):723-740, 2012; "High Educ Res Dev" 32(1):136-151, 2013)'s journal analysis and review framework to review a sample of 497 journal articles on researches concerning international students over the past 30 years. It was found…

Convergent close-coupling calculations of positron-magnesium scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Jeremy S.; Fursa, Dmitry V.; Bray, Igor

2011-06-15

The single-center convergent close-coupling method has been applied to positron-magnesium scattering at incident energies from 0.01 to 100 eV. Cross sections are presented for elastic scattering and excitation of 3 {sup 1}P, as well as for the total ionization and total scattering processes. We also provide an estimate of the positronium formation cross section. The results agree very well with the measurements of the total cross section by Stein et al. [Nucl. Instrum. Methods Phys. Res. Sect. B 143, 68 (1998)], and consistent with the positronium formation measurements of Surdutovich et al. [Phys. Rev. A 68, 022709 (2003)] for positronmore » energies above the ionization threshold. For energies below the positronium formation threshold (0.8 eV) we find a large P-wave resonance at 0.17 eV. A similar resonance behavior was found by Mitroy and Bromley [Phys. Rev. Lett. 98, 173001 (2007)] at an energy of 0.1 eV.« less

Internal Tide Generation by Steep Topography

DTIC Science & Technology

2007-09-01

acting on the barotropic tide ( Foda and Hill 1998) was incomplete. Kunze will put this work in the context of recent internal tide research and...Topographically generated internal waves in the open ocean. J. Geophys. Res., 80, 320-327. Foda , M.A., and D.F. Hill, 1998: Nonlinear energy...Bispectral analysis of energy transfer within the two-dimensional ocean internal wave field. . Phys. Oceanogr., 35, 2104-2109. Garrett, C., and E

Electron temperature response to ECRH on FTU tokamak in transient conditions.

NASA Astrophysics Data System (ADS)

Jacchia, A.; Bruschi, A.; Cirant, S.; Granucci, G.; Sozzi, C.; de Luca, F.; Amadeo, P.; Bracco, G.; Tudisco, O.

2001-10-01

Steady-state electron heat transport analysis of FTU high density plasmas under Electron Cyclotron Heating (ECRH) shows "stiff" electron temperature profiles [1,2,3]. Plasma response to off-axis EC heating, in fact, exibits a lower limit to electron temperature gradient length, Lc , below which electron thermal conductivity switches to higher values. Stiffness, however, is attenuated in the plasma core of saw-tooth free discharges with flat-hollow temperature profile and during current ramp-up [3,4,5], in which cases the temperature gradient length can be brought to very low values by means of on-axis ECH. Steady and current ramp-up discharges probed by steady and modulated ECH are analyzed in terms of stiffnes. Critical gradient length dependence on local features of computed current density profile is discussed. [1] Sozzi, C. et al., Paper EXP5/13, Plasma Phys. Contr. Fus. Res., Proc.18th IAEA Conf., Sorrento, 2000. [2] Jacchia, A. et al. Topical Conference on Radio Frequency Power in Plasmas, Oxnard, USA, (2001). [3] Cirant, S. et al. Topical Conference on Radio Frequency Power in Plasmas, Oxnard, USA, (2001). [4] Sozzi, C. et al., EPS, Madeira 2001. [5] Bracco, G. et al.,Plasma Phys. Contr. Fus. Res., Proc.18th IAEA Conf., Sorrento, 2000.

Reply to ``Comment on `Minimal size of a barchan dune' ''

NASA Astrophysics Data System (ADS)

Parteli, E. J. R.; Durán, O.; Herrmann, H. J.

2007-12-01

We reply to the preceding comment by Andreotti and Claudin [Phys. Rev. E 76, 063301 (2007)] on our paper [Phys. Rev. E 75, 011301 (2007)]. We show that the equations of the dune model used in our calculations are self-consistent and effectively lead to a dependence of the minimal dune size on the wind speed through the saturation length. Furthermore, we show that Meridiani Planum ripples are probably not a good reference to estimate the grain size of Martian dune sands: the soil in the ripple troughs at the landing site is covered with nonerodible elements (“blueberries”), which increase the minimal threshold for saltation by a factor of 2.0. We conclude that, in the absence of large fragments as the ones found at the landing site, basaltic grains of diameter d=500±100μm that compose the large, typical dark Martian dunes [K. S. Edgett and P. R. Christensen, J. Geophys. Res. 96, 22765 (1991)] probably saltate during the strongest storms on Mars. We also show that the wind friction speed u∗≈3.0m/s that we found from the calculations of Martian dunes is within the values of maximum wind speeds that occur during Martian storms a few times a decade [R. E. Arvidson , Science 222, 463 (1983); H. J. Moore, J. Geophys. Res. 90, 163 (1985); R. Sullivan , Nature (London) 436, 58 (2005); D. J. Jerolmack , J. Geophys. Res. 111, E12S02 (2006)]. In this manner, the dune model predicts that Martian dunes can be formed under present Martian conditions, with no need to assume other conditions of wind and atmosphere that could have prevailed in the past.

High energy neutrinos from astrophysical accelerators of cosmic ray nuclei

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.

2008-02-01

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and/or photons. However, there will be a reduction in the predicted neutrino flux if cosmic ray sources accelerate not only protons but also significant numbers of heavier nuclei, as is indicated by recent air shower data. We consider plausible extragalactic sources such as active galactic nuclei, gamma ray bursts and starburst galaxies and demand consistency with the observed cosmic ray composition and energy spectrum at Earth after allowing for propagation through intergalactic radiation fields. This allows us to calculate the expected neutrino fluxes from the sources, normalized to the observed cosmic ray spectrum. We find that the likely signals are still within reach of next generation neutrino telescopes such as IceCube.PACS95.85.Ry98.70.Rz98.54.Cm98.54.EpReferencesFor a review, see:F.HalzenD.HooperRep. Prog. Phys.6520021025A.AchterbergIceCube CollaborationPhys. Rev. Lett.972006221101A.AchterbergIceCube CollaborationAstropart. Phys.262006282arXiv:astro-ph/0611063arXiv:astro-ph/0702265V.NiessANTARES CollaborationAIP Conf. Proc.8672006217I.KravchenkoPhys. Rev. D732006082002S.W.BarwickANITA CollaborationPhys. Rev. Lett.962006171101V.Van ElewyckPierre Auger CollaborationAIP Conf. Proc.8092006187For a survey of possible sources and event rates in km3 detectors see e.g.,W.BednarekG.F.BurgioT.MontaruliNew Astron. Rev.4920051M.D.KistlerJ.F.BeacomPhys. Rev. D742006063007A. Kappes, J. Hinton, C. Stegmann, F.A. Aharonian, arXiv:astro-ph/0607286.A.LevinsonE.WaxmanPhys. Rev. Lett.872001171101C.DistefanoD.GuettaE.WaxmanA.LevinsonAstrophys. J.5752002378F.A.AharonianL.A.AnchordoquiD.KhangulyanT.MontaruliJ. Phys. Conf. Ser.392006408J.Alvarez-MunizF.HalzenAstrophys. J.5762002L33F.VissaniAstropart. Phys.262006310F.W.SteckerC.DoneM.H.SalamonP.SommersPhys. Rev. Lett.6619912697(Erratum-ibid. 69 (1992) 2738)F.W.SteckerPhys. Rev. D722005107301A.AtoyanC.D.DermerPhys. Rev. Lett.872001221102L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B6002004202E.WaxmanJ.N.BahcallPhys. Rev. Lett.7819972292C.D.DermerA.AtoyanPhys. Rev. Lett.912003071102D.GuettaD.HooperJ.Alvarez-MunizF.HalzenE.ReuveniAstropart. Phys.202004429J.Alvarez-MunizF.HalzenD.W.HooperPhys. Rev. D622000093015A.LoebE.WaxmanJCAP06052006003S. Inoue, G. Sigl, F. Miniati, E. Armengaud, arXiv:astro-ph/0701167.E.WaxmanJ.N.BahcallPhys. Rev. D591999023002Phys. Rev. D642001023002K.MannheimR.J.ProtheroeJ.P.RachenPhys. Rev. D632001023003arXiv:astro-ph/9908031M.AhlersL.A.AnchordoquiH.GoldbergF.HalzenA.RingwaldT.J.WeilerPhys. Rev. D722005023001E.WaxmanAstrophys. J.4521995L1Note that the neutrino spectral shape can deviate from that for protons if the Feynman plateau is not flat in pseudo-rapidity space;L.AnchordoquiH.GoldbergC.NunezPhys. Rev. D712005065014This is in fact suggested by Tevatron data;F.AbeCDF CollaborationPhys. Rev. D4119902330J.G.LearnedS.PakvasaAstropart. Phys.31995267F.HalzenD.SaltzbergPhys. Rev. Lett.8119984305J.F.BeacomN.F.BellD.HooperS.PakvasaT.J.WeilerPhys. Rev. D682003093005(Erratum-ibid. D 72 (2005) 019901)L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B593200442L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B621200518A.M.HillasAnn. Rev. Astron. Astrophys.221984425For a general discussion on the acceleration time-scale in these sources see, e.g.,D.F.TorresL.A.AnchordoquiRep. Prog. Phys.6720041663M.C.BegelmanB.RudakM.SikoraAstrophys. J.362199038M.J.ChodorowskiA.A.ZdziarskiM.SikoraAstrophys. J.4001992181S.MichalowskiD.AndrewsJ.EickmeyerT.GentileN.MistryR.TalmanK.UenoPhys. Rev. Lett.391977737J.L.PugetF.W.SteckerJ.H.BredekampAstrophys. J.2051976638D.HooperS.SarkarA.M.TaylorAstropart. Phys.272007199The non-thermal energy release in GRBs is much smaller than that output by AGN.P.L.BiermannP.A.StrittmatterAstrophys. J.3221987643R.J.ProtheroeA.P.SzaboPhys. Rev. Lett.6919922885J.P.RachenP.L.BiermannAstron. Astrophys.2721993161J.P.RachenT.StanevP.L.BiermannAstron. Astrophys.2731993377R.C.HartmanEGRET CollaborationAstrophys. J. Suppl.123199979See e.g.,M.PunchNature3581992477D.PetryHEGRA CollaborationAstron. Astrophys.3111996L13P.M.ChadwickAstrophys. J.5131999161C.D.DermerR.SchlickeiserA.MastichiadisAstron. Astrophys.2561992L27S.D.BloomA.P.MarscherAstrophys. J.4611996657K.MannheimAstron. Astrophys.269199367K.MannheimScience2791998684A.DarA.LaorAstrophys. J.4781997L5F.A.AharonianNew Astron.52000377M.BoettcherAstrophys. J.5151999L21C.D.DermerR.SchlickeiserAstrophys. J.4161993458F.W.SteckerPhys. Rev. Lett.2119681016G.J.FishmanC.A.MeeganAnn. Rev. Astron. Astrophys.331995415For a list of papers related to SWIFT, see: http://swift.gsfc.nasa.gov/docs/swift/results/publist/.B.LinkR.I.EpsteinAstrophys. J.4661996764C.A.MeeganNature3551992143M.R.MetzgerNature3871997878See e.g.,T.PiranPhys. Rep.3141999575T.PiranPhys. Rep.3332000529For a recent review of GRB phenomenology, see:P.MeszarosRep. Prog. Phys.6920062259E.WaxmanLect. Notes Phys.5762001122M.MilgromV.UsovAstrophys. J.4491995L37E.WaxmanPhys. Rev. Lett.751995386M.VietriPhys. Rev. Lett.7819974328D.BandAstrophys. J.4131993281F. Halzen, in: K. Oliver (Ed.), Proceedings of the TASI’98, Boulder, 1998, p. 524.J.W.ElbertP.SommersAstrophys. J.4411995151L.A.AnchordoquiG.E.RomeroJ.A.CombiPhys. Rev. D601999103001L.A. Anchordoqui, J.F. Beacom, H. Goldberg, S. Palomares-Ruiz, T.J. Weiler, arXiv:astro-ph/0611580; arXiv:astro-ph/0611581.The factor 9/(4R) results from calculating ∫dr∫dr|r-r|(4πR/3), where r is the position of a star and r is the position of an observer (the position of the reaction), in a region of radius R uniformly filled with sources.D.A.ForbesM.J.WardV.RotaciucM.BlietzR.GenzelS.DrapatzP.P.van der WerfA.KrabbeAstrophys. J.4061993L11P. Chanial, H. Flores, B. Guiderdoni, D. Elbaz, F. Hammer, L. Vigroux, arXiv:astro-ph/0610900.P.O.LagageC.J.CesarskyAstron. Astrophys.1181983223S.P.LaiJ.M.GirartR.CrutcherAstrophys. J.5982003392W.BednarekMon. Not. R. Astron. Soc.3452003847W.BednarekR.J.ProtheroeAstropart. Phys.162002397P.BlasiA.V.OlintoPhys. Rev. D591999023001F.W.SteckerAstropart. Phys.262007398F.W. Stecker, arXiv:astro-ph/0610208.A γ-ray signal from the nearby starburst galaxy NGC253 was reported by the CANGAROO-II Collaboration but their subsequent re-analysis of the data is consistent with the expectation from backgrounds:C.ItohCANGAROO-II CollaborationAstron. Astrophys.3962002L1(Erratum-ibid. 462 (2007) 67)T.A. Thompson, E. Quataert, E. Waxman, A. Loeb, arXiv:astro-ph/0608699.D.J.BirdFly’s Eye CollaborationPhys. Rev. Lett.7119933401D.R.BergmanHiRes CollaborationNucl. Phys. Proc. Suppl.136200440T.Abu-ZayyadHiRes-MIA CollaborationAstrophys. J.5572001686M.NaganoJ. Phys. G181992423V.BerezinskyA.Z.GazizovS.I.GrigorievaPhys. Rev. D742006043005R.U.AbbasiHiRes CollaborationPhys. Rev. Lett.922004151101V.BerezinskyA.Z.GazizovS.I.GrigorievaPhys. Lett. B6122005147V.S.BerezinskyS.I.GrigorievaB.I.HnatykAstropart. Phys.212004617See Fig. 21 in:L.AnchordoquiM.T.DovaA.MariazziT.McCauleyT.PaulS.ReucroftJ.SwainAnn. Phys.3142004145D.AllardE.ParizotE.KhanS.GorielyA.V.OlintoAstron. Astrophys.4432005L29D.AllardE.ParizotA.V.OlintoAstropart. Phys.27200761T.Abu-ZayyadHigh Resolution Fly’s Eye CollaborationAstropart. Phys.232005157P. Sommers, et al., Pierre Auger Collaboration, arXiv:astro-ph/0507150.R.U.AbbasiHiRes CollaborationAstrophys. J.6222005910B.N. Afanasiev, et al., Yakutsk Collaboration, in: M. Nagano (Ed.), Proceedings of the Tokyo Workshop on Techniques for the Study of the Extremely High Energy Cosmic Rays, 1993.J. Knapp, private communication.J.RanftPhys. Rev. D51199564R.S.FletcherT.K.GaisserP.LipariT.StanevPhys. Rev. D5019945710J.EngelT.K.GaisserT.StanevP.LipariPhys. Rev. D4619925013N.N.KalmykovS.S.OstapchenkoA.I.PavlovNucl. Phys. Proc. Suppl.52B19977It is important to stress that the Auger data are still at a preliminary stage and the reconstruction procedures are still to be finalised. However, even allowing for the systematic uncertainties still present, it does appear that at the highest energies fewer events are seen than expected from the AGASA analysis.V.S.BerezinskyG.T.ZatsepinPhys. Lett. B281969423F.W.SteckerAstrophys. J.2281979919R.EngelD.SeckelT.StanevPhys. Rev. D642001093010Z.FodorS.D.KatzA.RingwaldH.TuJCAP03112003015D.De MarcoT.StanevF.W.SteckerPhys. Rev. D732006043003D.HooperA.TaylorS.SarkarAstropart. Phys.23200511M.AveN.BuscaA.V.OlintoA.A.WatsonT.YamamotoAstropart. Phys.23200519A point worth noting at this juncture: If iron nuclei are accelerated to very high energies (much higher than the energy spectrum has been measured), then disintegration can lead to large numbers of protons above the spectrum cutoff. In this case, the resulting cosmogenic neutrino flux is not dramatically suppressed. On the other hand, if iron nuclei are only largely accelerated to around 10eV or less, then the liberated protons will only rarely interact with the CMB to produce pions, hence the cosmogenic neutrino flux will be significantly reduced.

A Comparison of Optically Measured and Radar-Derived Horizontal Neutral Winds

DTIC Science & Technology

1990-01-01

observations of large-scale gravity waves or3 traveling ionospheric disturbances by Testud [1970], Iunsucker [1982]. The contributions of the parallel...increase in Kp, in agreement with previous findings of excitation by auroral processes [ Testud , 1970; lHernandez and Roble, 1976b; lunsucker, 19821...and 0+ and H+ ions, J. Geophys. Res., 69, 2349-2355, 1964. Testud , J., Gravity waves generated during magnetic substorms, J. Atmos. Terr. Phys., 32

Perceived impact of the 80-hour workweek: five years later.

PubMed

Dozois, Eric J; Holubar, Stefan D; Tsikitis, Vassiliki L; Malireddy, Kishore; Cima, Robert R; Farley, David R; Larson, David W

2009-09-01

We aimed to assess perceptions of the effects of the 80-hour workweek (80hWW) restriction on patient care, education, and resident quality of life. In April 2007, attending surgeons and residents in nine surgical specialties at our institution were surveyed. Respondents were categorized into three groups: (1) attending surgeons; (2) residents beginning their training before the 80hWW implementation (ResBefore); and (3) residents beginning training after the 80hWW implementation (ResAfter). Differences between groups were assessed with univariate analysis. The overall response rate was 57%. A minority in all three groups (< or =33%) believed the 80hWW improved patient care. Fifteen percent of attending surgeons, 30% of ResBefore, and 67% of ResAfter believed patients were safer (P < 0.001). Eighty-three percent of attending surgeons, 74% of ResBefore, and 41% of ResAfter (P < 0.001) believed continuity of care was compromised. All groups (> or =84%) agreed that midlevel providers were now critical to successfully deliver health care (P = 0.40). Fewer attending surgeons (21%) and ResBefore (29%) perceived improvements in education compared with ResAfter (68%; P <0.001). A majority perceived improved work-life balance for residents (attending surgeons [85%], ResBefore [71%], and ResAfter [92%]; P = 0.008), but 76% of attending surgeons reported decreased job satisfaction. We showed a discrepancy between perceptions of attending surgeons and residents regarding the effect of the 80hWW on patient care and surgical education. Quality of life was improved for residents but not for attending surgeons. The impact of the 80hWW on patient care and surgical education needs to be quantified.

Characterising Biomass Burning Aerosol in WRF-Chem using the Volatility Basis Set, with Evaluation against SAMBBA Flight Data

NASA Astrophysics Data System (ADS)

Lowe, D.; Topping, D. O.; Archer-Nicholls, S.; Darbyshire, E.; Morgan, W.; Liu, D.; Allan, J. D.; Coe, H.; McFiggans, G.

2015-12-01

The burning of forests in the Amazonia region is a globally significant source of carbonaceous aerosol, containing both absorbing and scattering components [1]. In addition biomass burning aerosol (BBA) are also efficient cloud condensation nuclei (CCN), modifying cloud properties and influencing atmospheric circulation and precipitation tendencies [2]. The impacts of BBA are highly dependent on their size distribution and composition. A bottom-up emissions inventory, the Brazilian Biomass Burning Emissions Model (3BEM) [3], utilising satellite products to generate daily fire emission maps is used. Injection of flaming emissions within the atmospheric column is simulated using both a sub-grid plume-rise parameterisation [4], and simpler schemes, within the Weather Research and Forecasting Model with Chemistry (WRF-Chem, v3.4.1) [5]. Aerosol dynamics are simulated using the sectional MOSAIC scheme [6], incorporating a volatility basis set (VBS) treatment of organic aerosol [7]. For this work we have modified the 9-bin VBS to use the biomass burning specific scheme developed by May et al. [8]. The model has been run for September 2012 over South America (at a 25km resolution). We will present model results evaluating the modelled aerosol vertical distribution, size distribution, and composition against measurements taken by the FAAM BAe-146 research aircraft during the SAMBBA campaign. The main focus will be on investigating the factors controlling the vertical gradient of the organic mass to black carbon ratio of the measured aerosol. This work is supported by the Nature Environment Research Council (NERC) as part of the SAMBBA project under grant NE/J010073/1. [1] D. G. Streets et al., 2004, J. Geophys. Res., 109, D24212. [2] M. O. Andreae et al., 2004, Science, 303, 1337-1342. [3] K. Longo et al., 2010, Atmos. Chem. Phys., 10, 5,785-5,795. [4] S. Freitas et al., 2007, Atmos. Chem. Phys., 7, 3,385-3,398. [5] S. Archer-Nicholls et al., 2015, Geosci. Model Dev., 8, 549-577 [6] R. Zavari et al., 2008, J. Geophys. Res., 113, D132024. [7] M. Shrivastava et al., 2011, Atmos. Chem. Phys., 11, 6639-6662 [8] A. May et al., 2013, J. Geophys. Res., 118, 11,327-11,338

Theoretical Study of Topside Ionospheric Clutter

DTIC Science & Technology

1992-07-15

investigated. 4. References: Foster. J.C.. C. del Pozo. K. Groves, and J.-P. St. Maurice , Radar observations of the onlst of current drivenr instabilities... Clemmons , and F. S. Mozer, High-resolution sounding rocket observations of large-amplitude Alfvin waves, J. Geophys. Res., 95, 12157-12171, 1990. [51 Breit...equilibrium. Can. J. Phys., 38, 1114-1133, 1960. i16] Foster, J. C., C. del Pozo, K. Groves, and J.-P. St. Maurice , Radar observations of the onset of

Reactivity of Metal Nitrates.

DTIC Science & Technology

1982-07-20

02NOCuOH Any mechanism suggested for the nitration of aromatic systems by titanium(IV) nitrate must take into account the observed similarity, in...occurs. -26- References 1. For recent reviews see (a) R. B. Moodie and K. Schofield, Accounts Chem. Res., 1976, 9, 287; (b) G. A. Olah and S. J. Kuhn...Ithaca, N.Y., 1969, Chapter VI; L. M. Stock, Prog. Phys. Org. Chem., 1976, 12, 21; J. G. Hoggett , R. B. Moodie, J. R. Penton, and K. Schofield

Asymptotics of quantum weighted Hurwitz numbers

NASA Astrophysics Data System (ADS)

Harnad, J.; Ortmann, Janosch

2018-06-01

This work concerns both the semiclassical and zero temperature asymptotics of quantum weighted double Hurwitz numbers. The partition function for quantum weighted double Hurwitz numbers can be interpreted in terms of the energy distribution of a quantum Bose gas with vanishing fugacity. We compute the leading semiclassical term of the partition function for three versions of the quantum weighted Hurwitz numbers, as well as lower order semiclassical corrections. The classical limit is shown to reproduce the simple single and double Hurwitz numbers studied by Okounkov and Pandharipande (2000 Math. Res. Lett. 7 447–53, 2000 Lett. Math. Phys. 53 59–74). The KP-Toda τ-function that serves as generating function for the quantum Hurwitz numbers is shown to have the τ-function of Okounkov and Pandharipande (2000 Math. Res. Lett. 7 447–53, 2000 Lett. Math. Phys. 53 59–74) as its leading term in the classical limit, and, with suitable scaling, the same holds for the partition function, the weights and expectations of Hurwitz numbers. We also compute the zero temperature limit of the partition function and quantum weighted Hurwitz numbers. The KP or Toda τ-function serving as generating function for the quantum Hurwitz numbers are shown to give the one for Belyi curves in the zero temperature limit and, with suitable scaling, the same holds true for the partition function, the weights and the expectations of Hurwitz numbers.

Scaled experimental investigation of the moderation of auroral cyclotron emissions by background plasma

NASA Astrophysics Data System (ADS)

McConville, S. L.; Speirs, D. C.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Koepke, M. E.; Whyte, C. G.; Matheson, K.; Robertson, C. W.; Cairns, R. A.; Vorgul, I.; Bingham, R.; Kellett, B. J.; Ronald, K.

2012-04-01

Scaled laboratory experiments have been conducted at Strathclyde University [1,2] to further the understanding of the naturally occurring generation of Auroral Kilometric Radiation (AKR) in the Earth's polar magnetosphere. At an altitude of around 3200km there exists a region of partial plasma depletion (the auroral density cavity), through which electrons descend towards the Earth's atmosphere and are subject to magnetic compression. Due to conservation of the magnetic moment these electrons sacrifice parallel velocity for perpendicular velocity resulting in a horseshoe shaped distribution in velocity space which is unstable to the cyclotron maser instability [3,4]. The radiation is emitted at frequencies extending down to the local electron cyclotron frequency with a peak in emission at ~300kHz. The wave propagation is in the X-mode with powers ~109W corresponding to radiation efficiencies of 1% of the precipitated electron kinetic energy [5]. The background plasma frequency within the auroral density cavity is approximately 9kHz corresponding to an electron plasma density ~106m-3. Previous laboratory experiments at Strathclyde have studied cyclotron radiation emission from electron beams which have horseshoe shaped velocity distributions. Radiation measurements showed emissions in X-like modes with powers ~20kW and efficiencies ~1-2%, coinciding with both theoretical and numerical predictions [6-9] and magnetospheric studies. To enhance the experimental reproduction of the magnetospheric environment a Penning trap was designed and incorporated into the existing apparatus [10]. The trap was placed in the wave generation region where the magnetic field would be maintained at ~0.21T. The trap allowed a background plasma to be generated and its characteristics were studied using a plasma probe. The plasma had a significant impact on the radiation generated, introducing increasingly sporadic behaviour with increasing density. The power and efficiency of the radiation generated was lower than with no plasma present. Plasma diagnostics established the plasma frequency on the order of 150-300MHz and electron density ranging from ~1014-1015m-3, whilst the cyclotron frequency of the electrons within the Penning trap was 5.87GHz giving fce/fpe ~19-40, comparable to the auroral density cavity. Numerical simulations coinciding with this part of the experimental research program are currently being carried out using the VORPAL code. Details of these simulations will be presented in a separate paper [Speirs et al] at this meeting. McConville SL et al 2008, Plasma Phys. Control. Fusion, 50, 074010 Ronald et al 2011, Plasma Phys. Control. Fusion, 53, 074015 Bingham R and Cairns RA, 2002, Phys. Scr., T98, 160-162 Ergun RE et al, 1998, Geophys. Res. Lett., 25, 2061 Gurnett DA et al, 1974, J. Geophys. Res., 79, 4227-4238 Cairns RA et al, 2011, Phys. Plasmas, 18, 022902 Gillespie KM et al, 2008, Plasma Phys. Control. Fusion, 50, 124038 Speirs et al 2010, Phys. Plasmas, 17, 056501 Vorgul et al 2011, Phys. Plasmas, 18, 056501 McConville SL et al 2011, Plasma Phys. Control. Fusion, 53, 124020

On the calculation of line strengths, oscillator strengths and lifetimes for very large principal quantum numbers in hydrogenic atoms and ions by the McLean-Watson formula

NASA Astrophysics Data System (ADS)

Hey, J. D.

2014-08-01

As a sequel to an earlier study (Hey 2009 J. Phys. B: At. Mol. Opt. Phys. 42 125701), we consider further the application of the line strength formula derived by Watson (2006 J. Phys. B: At. Mol. Opt. Phys. 39 L291) to transitions arising from states of very high principal quantum number in hydrogenic atoms and ions (Rydberg-Rydberg transitions, n > 1000). It is shown how apparent difficulties associated with the use of recurrence relations, derived (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641) by the ladder operator technique of Infeld and Hull (1951 Rev. Mod. Phys. 23 21), may be eliminated by a very simple numerical device, whereby this method may readily be applied up to n ≈ 10 000. Beyond this range, programming of the method may entail greater care and complexity. The use of the numerically efficient McLean-Watson formula for such cases is again illustrated by the determination of radiative lifetimes and comparison of present results with those from an asymptotic formula. The question of the influence on the results of the omission or inclusion of fine structure is considered by comparison with calculations based on the standard Condon-Shortley line strength formula. Interest in this work on the radial matrix elements for large n and n‧ is related to measurements of radio recombination lines from tenuous space plasmas, e.g. Stepkin et al (2007 Mon. Not. R. Astron. Soc. 374 852), Bell et al (2011 Astrophys. Space Sci. 333 377), to the calculation of electron impact broadening parameters for such spectra (Watson 2006 J. Phys. B: At. Mol. Opt. Phys. 39 1889) and comparison with other theoretical methods (Peach 2014 Adv. Space Res. in press), to the modelling of physical processes in H II regions (Roshi et al 2012 Astrophys. J. 749 49), and the evaluation bound-bound transitions from states of high n during primordial cosmological recombination (Grin and Hirata 2010 Phys. Rev. D 81 083005, Ali-Haïmoud and Hirata 2010 Phys. Rev. D 82 063521, Ali-Haïmoud 2013 Phys. Rev. D 87 023526).

Mesoscale Characteristics and the Role of Deformation on Ocean Dynamics

DTIC Science & Technology

1991-06-05

34 Thilus, 41 (A), 416-435, 1989. 3. "Ring Evolution in General Circulation Models from Path Analysis ," J. Geo- phys. Res., 95(C10), 18057-18073, 1990...Loop Curren: (up to three in I year [Elliot,. by Vaukovih and Crt, ,tman (19861. Analysis of drifter data 19821). Lewi.a and Kirwan (1983. 19871...seventh drifter. the Lagrangian data sets along with an analysis and anterpre- number 3354. was entrained in the Loop Current at the tim. tation of

High Resolution Studies of the Structure of the Solar Atmosphere

DTIC Science & Technology

1993-08-04

two-fluid solar wind model", submitted to J. Geophys. Res., August 1993. M. B. Arndt, S. R. Habbal, and M. Karovska , "Discrete and localized nature of...the variable emission from active regions", submitted to Solar Phys., August 1993. M. Karovska and F. Blundell, "The fine structure at the limb in a...coronal hole", submitted to Ap. J, August 1993. M. Karovska , M. Arndt and S. R. Habbal, "Spatial and temporal variability of the emission at the limb

Wave Structures in Thermospheric Density from Satellite Electrostatic Triaxial Accelerometer Measurements.

DTIC Science & Technology

1987-06-04

Testud , J. (1970) Gravity waves generated diring magnetic substorms, .1. Atmos. Terr. Phys., 32:1793. .6 t9, "-€ according to their horizontal...auroral oval during polar substorms, J. Geophys. Res., 74:5721. 7. Testud , J. P., Amayenc, P., and Blanc, M. (1975) Middle and low latitude effects of...1730. 13. Bertin, F.J., Testud , J., Kersley, L., and Rees, P. R. (1978) The meteorological jet stream as a source of medium scale gravity waves in

Thermophysical Properties of Matter-The TPRC Data Series. Volume 10. Thermal Diffusivity

DTIC Science & Technology

1974-01-01

Encyclopaedia Britannica, The 19. Mikryukov , V . E ., "Temperature Dependence of the Heat Encyclopaedia Britannica Co.. New York, 11th Edition, Conductivity and...translation: Phys. Metals and Metallog. USSR, 12 (4), 39-44, 1962. 54 27539 Mikryukov , V . E . and Karagezyan, A. G., "Thermal and Electrical Properties of...Chem. Res., 62 (1), 8-13, 1968. 248 38076, Kirichenko, P.1. and Mikryukov , V . E ., "Thermal and Electrical Properties of Some Alloys of the 36392

A review of astrophysics experiments on intense lasers

NASA Astrophysics Data System (ADS)

Remington, B. A.

1999-11-01

Modern, high power laser facilities open new possibilities for simulating astrophysical systems in the laboratory.(S.J. Rose, Laser & Part. Beams 9, 869 (1991); B.H. Ripin et al., Laser & Part. Beams 8, 183 (1990); B.A. Remington et al., Science 284, 1488 (1999); H. Takabe et al., Plasma Phys. Contr. Fusion 41, A75 (1999); R.P. Drake, J. Geophys. Res. 104, 14505 (1999).) Scaled investigations of the hydrodynamics.(J. Kane et al., Phys. Plasmas 6, 2065 (1999); R.P. Drake et al., Ap. J. 500, L157 (1998); D. Ryutov et al., Ap. J. 518, 821 (1999).) and radiative transfer.(J. Wark et al., Phys. Plasmas 4, 2004 (1997); P.K. Patel et al., JQSRT 58, 835 (1997).) relevant to supernovae, and opacities relevant to stellar interiors.(F.J. Rogers and C.A. Iglesias, Science 263, 50 (1994); H. Merdji et al., JSQRT 58, 783 (1997).) are now possible with laser experiments. Equations of state relevant to the interiors of giant planets and brown dwarfs are also being experimentally accessed.(G.W. Collins et al., Science 281, 1178 (1998); A. Benuzzi et al., Phys. Rev. E 54, 2162 (1996).) With the construction of the NIF laser in the U.S., and the LIL and LMJ lasers in France, controlled investigations of thermonuclear burn physics will become possible in the next decade. And with existing and future ultra-high intensity short pulse lasers, investigations of relativistic astrophysical plasmas are becoming possible.(M.H. Key et al., Phys. Plasmas 5, 1966 (1998); F. Pegoraro et al., Plasma Phys. Contr. Fus. 39, B261 (1997).) A review of laboratory astrophysics experiments using intense lasers will be presented, and the potential for the future will be discussed.

On The Constitutive Properties Of Strongly Magnetized Matter Observed In A Class Of Solar Ejecta

NASA Astrophysics Data System (ADS)

Berdichevsky, D. B.

2013-12-01

Several studies of the transient events known as magnetic clouds at 1 AU suggest that they possess the ';1/2' anomalous value for its adiabatic, polytropic index, i.e., γ= 1/2, which implies that the temperature of the plasma decreases with increased density[1-3]. Coronal mass ejections commonly observed by missions like The Solar Terrestrial Relations Observatory (STEREO) have been successfully modeled previously by Berdichevsky Stenborg and Vourlidas[4] as magnetic flux-ropes which propagate from the Sun with uniform velocity. Building on this existing analytical three-dimensional magnetohydrodynamic (MHD) model of a magnetic flux-rope, we present an interpretation of the anomalous and somewhat counterintuitive dynamic property mentioned above. Using plasma and magnetic field observations by the Wind spacecraft for the magnetic cloud of June 2, 1998, we argue that this anomalous polytropic index is indeed a consequence of thermodynamic processes in this strongly magnetized matter. We show that the derived models of Berdichevsky et al.[5, 6] easily accommodate a familiar thermodynamic explanation of this property. Such an explanation may shed light also on the evolution of other astrophysical observations such as remnants in nebulae of past super-novae, as well other transient interstellar events. This MHD solution may be a good way to go beyond gas-dynamics in the development of a coherent picture of shock and its driver, as they are becoming a current interpretation. 1Osherovich, V.A., 1997, Proc. 31st, ESLAB Symp. Correlated Phenomena at the Sun, in the Heliosphere and in Geospace. 2Sittler, E.C., and L.F., Burlaga, 1998, J. Geophys. Res., 103, 17447. 3Nieves-Chinchilla T., and A., Figueroa-Viñas, 2008, J. Geophys. Res., 113, DOI: 10.1029/2007JA012703 4Berdichevsky, Stenborg, and Vourlidas, 2011, ApJ, 741, 47. 5Berdichevsky, D.B., R.L., Lepping, C.J., Farrugia, 2003, Phys.Rev. E, 67, DOI: 10.1103/PhysRevE036405. 6Berdichevsky, D.B. , 2012, Sol. Phys., 284, 245.

Linear lateral vibration of axisymmetric liquid briges

NASA Astrophysics Data System (ADS)

Ferrera, C.; Montanero, J. M.; Cabezas, M. G.

A liquid bridge is a mass of liquid sustained by the action of the surface tension force between two parallel supporting disks Apart from their basic scientific interest a liquid bridge can be considered as the simplest idealization of the configuration appearing in the floating zone technique used for crystal growth and purification of high melting point materials footnote Messeguer et al emph Crystal Growth Res bf 5 27 1999 This has conferred considerable interest on the study of liquid bridges not only in fluid mechanics but also in the field of material engineering The axisymmetric dynamics of an isothermal liquid bridge has been frequently analysed over the past years The studies have considered different phenomena such as free oscillations footnote Montanero emph E J Mech B Fluids bf 22 169 2003 footnote Acero and Montanero emph Phys Fluids bf 17 078105 2005 forced vibrations footnote Perales and Messeguer emph Phys Fluids A bf 4 1110 1992 g-jitter effects footnote Messeguer and Perales emph Phys Fluids A bf 3 2332 1991 extensional deformation footnote Zhang et al emph J Fluid Mech bf 329 207 1996 and breakup process footnote Espino et al emph Phys Fluids bf 14 3710 2002 among others Works considering the nonaxisymmetric dynamical behaviour of a liquid bridge has been far less common footnote Sanz and Diez emph J Fluid Mech bf 205 503 1989 In the present study the linear vibration of an axisymmetric liquid

On the interconnection between Natural Time and Network Theory as a tool for predicting extreme events in seismology

NASA Astrophysics Data System (ADS)

Sarlis, N. V.; Skordas, E. S.; Varotsos, P.

2009-12-01

A new time domain, termed natural time χ, has been introduced by the authors[1]. This enables, among others, the distinction of Seismic Electric Signals (SES), which are low frequency geoelectric signals (≤1Hz) characterized by critical dynamics and precede earthquakes, from noise emitted from human made sources[2]. If one analyzes in natural time the seismicity subsequent to the SES by using an appropriately constructed network of earthquakes, the time of the impending mainshock can be identified within a few days[3-8]. The values of natural time specify the nodes of this network. Examples are presented, which include the prediction of the largest earthquake that occurred in Greece during the last twenty five years [9]. These examples provide evidence that natural time in conjunction with network theory is beneficial for the prediction of extreme events in seismology[3-6,8] and volcanology[7]. References: [1] P.A. Varotsos, N.V. Sarlis, and E.S. Skordas, Phys. Rev. E 66 , 011902 (2002). [2] P.A. Varotsos, N.V. Sarlis, and E.S. Skordas, Phys. Rev. E 67 , 021109 (2003); 68 , 031106 (2003); Phys. Rev. Lett. 91, 148501(2003). [3] P.A. Varotsos, N.V. Sarlis, H.K. Tanaka, and E.S. Skordas, Phys. Rev. E 72, 041103 (2005). [4] P. A. Varotsos, N. V. Sarlis, E. S. Skordas, H. K. Tanaka, and M. S. Lazaridou, Phys. Rev. E 73 , 031114 (2006); 74 , 021123 (2006). [5] P. A. Varotsos, N. V. Sarlis, E. S. Skordas, and M. S. Lazaridou, J. Appl. Phys. 103 , 014906 (2008). [6] N. V. Sarlis, E. S. Skordas, M. S. Lazaridou, and P. A. Varotsos, Proc. Jpn. Acad., Ser. B: Phys. Biol. Sci. 84 , 331 (2008) [7] S. Uyeda, M. Kamogawa and H. Tanaka, J. Geophys. Res. 114, B02310 (2009). [8] P. A. Varotsos, N. V. Sarlis and E. S. Skordas, CHAOS 19 , 023114 (2009). [9] Uyeda, S., and Kamogawa, M. Eos Trans. AGU 89 , 363 (2008).

Nonlinear heating of ions by electron cyclotron frequency waves

NASA Astrophysics Data System (ADS)

Zestanakis, P. A.; Hizanidis, K.; Ram, A. K.; Kominis, Y.

2010-11-01

We study the nonlinear interaction of ions with electron cyclotron (EC) wave packets in a magnetized plasma. Previous studies have shown that such interactions with high frequency electrostatic lower hybrid waves can lead to coherent energization of ions. It requires the frequency bandwidth of the wave packet to be broader than the ion cyclotron frequency [1,2]. For the electromagnetic high frequency EC waves we have developed a more general theory, based on the Lie transform canonical perturbation method [3,4]. We apply the theory to the case of two overlapping EC beams. The wave frequency of each beam is assumed to be frequency modulated with a modulation bandwidth comparable to the ion cyclotron frequency. We present results for both X-mode and O-mode and illustrate the conditions for ion energization. [4pt] [1] D. Benisti, A. K. Ram, and A. Bers, Phys. Plasmas 5, 3224 (1998). [0pt] [2] A. K. Ram, A. Bers, and D. Benisti , J. Geophys. Res. 103, 9431 (1998). [0pt] [3] J.R. Cary and A.N. Kaufman, Phys. Fluids 24, 1238 (1981). [0pt] [4] R.L. Dewar, J. Phys A-Math. Gen 9, 2043 (1976).

Laboratory studies of key gas-phase HOx-NOx coupling reactions.

NASA Astrophysics Data System (ADS)

Dillon, Terry J.; Dulitz, Katrin; Crowley, John N.

2013-04-01

The HOx (OH & HO2) and NOx (NO & NO2) families of atmospheric radicals are coupled via a number of gas-phase reactions. These reactions have a substantial impact by controlling radical propagation / termination in catalytic cycles, so modifying the oxidation power of the atmosphere and its rate of O3 production. However, field measurements {1-3} have demonstrated that our understanding of HOx - NOx chemistry is incomplete. We have identified four reactions (R1-R4) where the database is particularly unsatisfactory, leading to large uncertainties in atmospheric models {4-5}. HO2 + NO -> OH + NO2 (R1a) HO2 + NO (+ M) -> HNO3 (+ M) (R1b) NO2* + H2O -> NO2 + H2O (R2a) NO2* + H2O -> OH + HONO (R2b) NO3* + H2O -> NO3 + H2O (R3a) NO3* + H2O -> OH + HNO3 (R3b) OH + HNO3 -> H2O + NO3 (R4) In this experimental work, laser-based kinetic and spectroscopic tools were used to investigate recent observations {6-7} of HNO3 formation from the (otherwise radical propagating) HO2 + NO (R1), and OH formation following absorption of abundant, long wavelength photons by NO2 {8} and NO3 in the presence of water vapour (R2, R3). Uncertainties {9} associated with a classical HOx-NOx coupling reaction (R4) were also addressed. Critical photochemical parameters so derived have included absolute rate coefficients for (R1) and (R4) and product yields (R1b, R2b, R3b). The atmospheric implications of these results will be discussed. References: {1} Faloona, I. et al. J. Geophys. Res., 105, 3771-3783, 2000.; {2} Thakur, A.N. et al., Atmos. Environ., 33, 1403-1422, 1999.; {3} Wennberg, P.O. et al., Geophys. Res. Lett., 26, 1373-1376, 1999.; {4} Cariolle, D. et al., Atmos. Chem. Phys., 8, 4061-4068, 2008.; {5} Wennberg P.O. and Dabdub, D. Science, 319, 2008. ; {6} Butkovskaya, N. et al., J. Phys. Chem. A, 111, 9047-9053, 2007.; {7} Butkovskaya, N. et al., J. Phys. Chem. A, 109, 6509-6520, 2005.; {8} Li, S.P. et al., Science, 319, 1657-1660, 2008. {9} Brown, S.S. et al., J. Phys. Chem., 103, 3031-3037, 1999.

Joint Services Electronic Program

DTIC Science & Technology

1991-06-01

Mitzi and A. Kapitulnik and J. S. Harris., Jr., "Optical Anisotropy of Bi2 Sr 2 CaCu2O8 ," Phys. Rev. B, 41, 10, April 1990. 14. P. Cheng and J. S...Pt Films on GaAs", Mat. Res. Soc. Symp. Proc. 181, 253 (1990). 28. Z.-X. Shen, P. A. P. Lindberg, B. 0. Wells, D. B. Mitzi , I. Lindau, W. E. Spicer and...Z.-X. Shen, P. A. P. Lindberg, D. S. Dessau, I. Lindau, D. B. Mitzi , I. Bozovic and A. Kapitulnik, "Photoelectron energy-loss study of the

Synthesis and Self-Assembly of Films Containing FeCoPt Nanoparticles

DTIC Science & Technology

2001-04-01

1989). 5. J.S. Yin and Z.L. Wang. .. Mater. Res. 14, 503 (1999). 6. T . Teranishi, M. Hosoe, T . Tanaka, and M. Miyaka. .1. Phys. Chem. B. 103, 3818 (1999...7. H. Kanazawa; G. Lauhoff; R. Sbiaa; T . Suzuki. Digests of the 8"h Joint MMM-Intermag Conference Jan. 7-11 2001, p. QC-03. 8. D. Weller, A. Moser...L. Folks, M. E. Best, W. Lee, M. F. Toney, M. Schwickert, J.-U. Thiele, and M. F. Doerner, IEEE Trans. Magn. 36, 10 (2000) 9. J. Numazawa and H

Microstructurally Adaptive Constitutive Relations and Reliability Assessment Protocols for Lead Free Solder

DTIC Science & Technology

2015-05-05

Chalmers, Can J Phys 30 (1952) pp. 488. [1.9] L.P. Lehman, S.N. Athavale, T.Z. Fullem, A.C. Giamis, R.K. Kinyanjui, M. Lowenstein, K. Mather , R... Mather , R. Patel, D. Rae, J. Wang, Y. Xing, L. Zavalij, P. Borgesen, E.J. Cotts, Journal of Electronic Materials 33 (2004) pp. 1429. [1.53] L.P...Res. 20 (2005) pp. 2914. 142 [1.72] Lehman L, Athavale S, Fullem T, Giamis A, Kinyanjui R, Lowenstein M, Mather K, Patel R, Rae D, Wang J, Xing Y

CoRes utilization for building PCK in pre-service teacher education on the digestive system topic

NASA Astrophysics Data System (ADS)

Nugraha, Ikmanda

2017-05-01

Knowledge of teachers in learning activities in the classroom has a close relationship with how well and how much students learn. Recently, a promising development in teacher education has appeared that centers on the academic construct of pedagogical content knowledge (PCK). This study was an exploratory study into a science teacher education program that seeks to build the foundations on which pre-service teachers can begin to build their pedagogical content knowledge (PCK). The program involved the use of Content Representations (CoRes), which was initially applied as component of a strategy for exploring and gaining insights into the PCK of in-service science teachers. This study involved the researcher and 20 students (third year) in a pre-service teacher education course (School Science I) in science education when the students worked to make content analysis on the digestive system topic. During the course, the students make their own CoRes through a workshop for digestive system topic individually, in pairs and whole class discussion. Data were recorded from students' CoRes, student reflective journals, interviews, and field notes recorded in the researcher's reflective journal. Pre-service teachers' comments from interviews and reflective journals were coded in relation to references about: (1) the effectiveness of variety strategies in building the knowledge bases required to design a CoRes and (2) their awareness and/or development of tentative components of future PCK for a digestive system topic as a result of CoRes construction. Observational data were examined for indications of increasing independence and competency on the part of student teachers when locating appropriate information for designing their CoRes. From this study, it is hoped that the pre-service science teachers are able to build knowledge and then transform it into a form of PCK for digestive system topic for their first classroom planning and teaching to teach digestive system contents effectively.

How gender and reformed introductory physics impacts student success in advanced physics courses and continuation in the physics major

NASA Astrophysics Data System (ADS)

Rodriguez, Idaykis; Potvin, Geoff; Kramer, Laird H.

2016-12-01

[This paper is part of the Focused Collection on Gender in Physics.] Active-learning approaches to teaching introductory physics have been found to improve student learning and affective gains on short-term outcomes [S. Freeman et al., Proc. Natl. Acad. Sci. U.S.A. 111, 8410 (2014)]; however, whether or not the benefits of active learning impact women to the same degree as men has been a point of concern [A. Madsen, S. B. McKagan, and E. C. Sayre, Phys. Rev. ST Phys. Educ. Res. 9, 020121 (2013)]. Further, the long-term impacts of active-learning experiences are also understudied. At Florida International University, a Hispanic-majority institution, we have implemented Modeling Instruction (MI) and the Integrated Science Learning Environment (ISLE) in introductory physics classes for the past decade. In this empirical paper, we report on a longitudinal investigation of student performance and persistence in upper level physics courses after having previously experienced MI or ISLE in their introductory physics courses, and disaggregate students by gender. Using survival analysis methods, we find women who declare physics as a major are more likely than men to graduate with a physics degree. Women are also just as likely as men to pass through the upper division courses, with the highest failure risk for both men and women occurring in the first semester of upper-division course taking. These results reinforce the need to expand considerations of performance outcomes to be longitudinal to measure the effectiveness of the entire physics experience.

Linear and nonlinear regimes of the 2-D Kelvin-Helmholtz/Tearing instability in Hall MHD.

NASA Astrophysics Data System (ADS)

Chacon, L.; Knoll, D. A.; Finn, J. M.

2002-11-01

The study to date of the magnetic field effects on the Kelvin-Helmholtz instability (KHI) within the framework of Hall MHD has been limited to configurations with uniform magnetic fields and/or with the magnetic field perpendicular to the sheared ion flow (( B_0⊥ v0 )).(E. N. Opp et al., Phys. Fluids B), 3, 885 (1990)^,(M. Fujimoto et al., J. Geophys. Res.), 96, 15725 (1991)^,(J. D. Huba, Phys. Rev. Lett.), 72, 2033 (1994) Here, we are concerned with the effects of Hall physics in configurations in which (B_0allel v0 ) and both are sheared.(L. Chacon et al, Phys. Lett. A), submitted (2002) In resistive MHD, and for this configuration, either the tearing mode instability (TMI) or the KHI instability dominates depending upon their relative strength.( R. B. Dahlburg et al., Phys. Plasmas), 4, 1213 (1997) In Hall MHD, however, Hall physics decouples the ion and electron flows in a boundary layer of thickness (d_i=c/ω_pi) (ion skin depth), within which electrons are the only magnetized species. Hence, while KHI essentially remains an ion instability, TMI becomes an electron instability. As a result, both KHI and TMI can be unstable simultaneously and interact, creating a very rich linear and nonlinear behavior. This is confirmed by a linear study of the Hall MHD equations. Nonlinearly, both saturated regimes and highly dynamic regimes (with vortex and magnetic island merging) are observed.

Light emitting diodes as a monitor to study P-type doping of GaN-based heterostructures grown by MOVPE

NASA Astrophysics Data System (ADS)

Schineller, B.; Guttzeit, A.; Vertommen, F.; Schön, O.; Heuken, M.; Heime, K.; Beccard, R.

1998-06-01

The group-III nitrides are an interesting material system for applications in the blue spectral region and for high-power and high-temperature devices. P-type doping in the metalorganic vapour-phase growth process, however, suffers from the material's high-background donor concentration. Hydrogen passivation furthermore decreases the number of activated acceptors [N.M. Johnson, W. Götz, J. Neugebauer, C.G. van de Walle, Mater. Res. Soc. Symp. Proc. 395 (1996) 723; A. Bosin, V. Fiorentini, Mater. Res. Soc. Symp. Proc. 395 (1996) 503] [1, 2]. Thermal treatment was found to increase the amount of activated acceptors [S.J. Pearton, S. Bendi, K.S. Jones, V. Krishnamoorthy, R.G. Wilson, F. Ren, R.F. Karlicek, R.A. Stall, Appl. Phys. Lett. 69 (1996) 1879; Y. Li, Y. Lu, H. Shen, M. Wraback, C.Y. Hwang, M. Schurman, W. Mayo, T. Salagaj, R.A. Stall, Mater. Res. Soc. Symp. Proc. 395 (1996) 369] [3, 4]. We have investigated the influences of thermal treatment process steps on the electrical and optical properties of Mg-doped single layers and used the results to fabricate AlGaN/GaN heterostructure LED layers. A simple test structure was employed to assess the electro-optical properties of the LED structures.

Model analysis of secondary organic aerosol formation by glyoxal in laboratory studies: the case for photoenhanced chemistry.

PubMed

Sumner, Andrew J; Woo, Joseph L; McNeill, V Faye

2014-10-21

The reactive uptake of glyoxal by atmospheric aerosols is believed to be a significant source of secondary organic aerosol (SOA). Several recent laboratory studies have been performed with the goal of characterizing this process, but questions remain regarding the effects of photochemistry on SOA growth. We applied GAMMA (McNeill et al. Environ. Sci. Technol. 2012, 46, 8075-8081), a photochemical box model with coupled gas-phase and detailed aqueous aerosol-phase chemistry, to simulate aerosol chamber studies of SOA formation by the uptake of glyoxal by wet aerosol under dark and irradiated conditions (Kroll et al. J. Geophys. Res. 2005, 110 (D23), 1-10; Volkamer et al. Atmos. Chem. Phys. 2009, 9, 1907-1928; Galloway et al. Atmos. Chem. Phys. 2009, 9, 3331- 306 3345 and Geophys. Res. Lett. 2011, 38, L17811). We find close agreement between simulated SOA growth and the results of experiments conducted under dark conditions using values of the effective Henry's Law constant of 1.3-5.5 × 10(7) M atm(-1). While irradiated conditions led to the production of some organic acids, organosulfates, and other oxidation products via well-established photochemical mechanisms, these additional product species contribute negligible aerosol mass compared to the dark uptake of glyoxal. Simulated results for irradiated experiments therefore fell short of the reported SOA mass yield by up to 92%. This suggests a significant light-dependent SOA formation mechanism that is not currently accounted for by known bulk photochemistry, consistent with recent laboratory observations of SOA production via photosensitizer chemistry.

Field signatures of non-Fickian transport processes: transit time distributions, spatial correlations, reversibility and hydrogeophysical imaging

NASA Astrophysics Data System (ADS)

Le Borgne, T.; Kang, P. K.; Guihéneuf, N.; Shakas, A.; Bour, O.; Linde, N.; Dentz, M.

2015-12-01

Non-Fickian transport phenomena are observed in a wide range of scales across hydrological systems. They are generally manifested by a broad range of transit time distributions, as measured for instance in tracer breakthrough curves. However, similar transit time distributions may be caused by different origins, including broad velocity distributions, flow channeling or diffusive mass transfer [1,2]. The identification of these processes is critical for defining relevant transport models. How can we distinguish the different origins of non-Fickian transport in the field? In this presentation, we will review recent experimental developments to decipher the different causes of anomalous transport, based on tracer tests performed at different scales in cross borehole and push pull conditions, and time lapse hydrogeophysical imaging of tracer motion [3,4]. References:[1] de Anna-, P., T. Le Borgne, M. Dentz, A. M. Tartakovsky, D. Bolster, P. Davy (2013) Flow Intermittency, Dispersion and Correlated Continuous Time Random Walks in Porous Media, Phys. Rev. Lett., 110, 184502 [2] Le Borgne T., Dentz M., and Carrera J. (2008) Lagrangian Statistical Model for Transport in Highly Heterogeneous Velocity Fields. Phys. Rev. Lett. 101, 090601 [3] Kang, P. K., T. Le Borgne, M. Dentz, O. Bour, and R. Juanes (2015), Impact of velocity correlation and distribution on transport in fractured media : Field evidence and theoretical model, Water Resour. Res., 51, 940-959 [4] Dorn C., Linde N., Le Borgne T., O. Bour and L. Baron (2011) Single-hole GPR reflection imaging of solute transport in a granitic aquifer Geophys. Res. Lett. Vol.38, L08401

Negative Differential Resistance in Insulating Systems: From Molecules to Polymers

NASA Astrophysics Data System (ADS)

Pati, Swapan

2007-03-01

We have developed a microscopic theory to explain the negative differential resistance behavior in molecular bridges. This feature has been observed in many molecules with different on/off ratios, sharpness of the current peak and the critical bias. Our theory, based on simple dimer model (both Peierls and donor/acceptor) together with bias driven conformational/ electronic change, covers almost all the experimental characteristics for a large number of real molecular systems and encompasses all the theory that has been known till date. Similar argument is also extended to Mott insulator, where we find a large number of insulator/quasi-metal transitions in finite size chains and a thermodynamic insulator/metal transition in polymers due to the application of static electric field between two ends of the chain. The interplay between charge inhomogenities and electric field induced polarization will be discussed in a number of cases. We will also show that none of these transitions follow Landau-Zener mechanism. I shall also discuss our theoretical proposal for the experimental strategies to stabilize highly unstable and reactive metal clusters like Al4Li4 and their analogs. Reference: 1. S. Lakshmi and Swapan K. Pati, Phys. Rev. B 72, 193410 (2005). 2. S. Lakshmi, Ayan Datta and Swapan K. Pati, Phys. Rev. B 72, 045131 (2005). 3. S. Lakshmi and Swapan K. Pati, Spl on Nanosc and Tech, Pramana, 65, 593. (2005). 4. S. Sengupta, S. Lakshmi and Swapan K Pati, J. Phys. Cond. Mat. 18, 9189 (2006). 5. Swapan K. Pati and S. Ramasesha, J. Phys. Condens. Matter 16, 989 (2004). 6. S.Lakshmi and Swapan K. Pati, J. Chem. Phys. 121, 11998 (2004). 7. S. Dutta, S. Lakshmi and Swapan K Pati, Submitted (2006). 8. A. Datta and Swapan K. Pati, J. Am. Chem. Soc. 127, 3496 (2005). 9. Sairam S. M., A. Datta and Swapan K. Pati, J. Phys. Chem. B 110, 20098 (2006). 10. A. Datta, Sairam S. M. and Swapan K. Pati, Acc. Chem. Res. (to appear)

Strong core hole in resonant inelastic x-ray scattering (RIXS)

NASA Astrophysics Data System (ADS)

Markiewicz, Robert; Rehr, John; Bansil, Arun

2014-03-01

We apply a lattice version of Mahan, Nozières, and de Dominicis theory1 to RIXS calculations to understand the role of the core hole. The model reproduces the decomposition of the RIXS spectrum into well- and poorly-screened components. While the calculation can reproduce the full multiband spectrum, single pair excitations contribute the dominant part to the RIXS spectrum, and they can be described as the dynamic structure function S(q , ω) dressed by matrix element effects. We find evidence for an edge singularity at the RIXS threshold, similar to that found in x-ray absorption. We will discuss comparisons with long core hole lifetime calculations, and extensions to a system with antiferromagnetic order. 1. G.D. Mahan, Phys. Rev. 163, 612 (1967); P. Nozières and C.T. De Dominicis, ibid. 178, 1097 (1969). Supported by DOE Grants DE-FG02-07ER46352 and DE-FG03-97ER45623 and facilitated by the DOE CMCSN, under grant number DE-SC0007091.

On the Ambjorn-Olesen electroweak condensates

NASA Astrophysics Data System (ADS)

Bartolucci, Daniele; De Marchis, Francesca

2012-07-01

We obtain sufficient conditions for the existence of the Ambjorn-Olesen ["On electroweak magnetism," Nucl. Phys. B315, 606-614 (1989), 10.1016/0550-3213(89)90004-7] electroweak N-vortices in case N ⩾ 1 and therefore generalize earlier results [D. Bartolucci and G. Tarantello, "Liouville type equations with singular data and their applications to periodic multivortices for the electroweak theory," Commun. Math. Phys. 229, 3-47 (2002), 10.1007/s002200200664; J. Spruck and Y. Yang, "On multivortices in the electroweak theory I: Existence of periodic solutions," Commun. Math. Phys. 144, 1-16 (1992), 10.1007/BF02099188] which handled the cases N ∈ {1, 2, 3, 4}. The variational argument provided here has its own independent interest as it generalizes the one adopted by Ding et al. ["Existence results for mean field equations," Ann. Inst. Henri Poincare, Anal. Non Lineaire 16, 653-666 (1999), 10.1016/S0294-1449(99)80031-6] to obtain solutions for Liouville-type equations on closed 2-manifolds. In fact, we obtain at once a second proof of the existence of supercritical conformal metrics on surfaces with conical singularities and prescribed Gaussian curvature recently established by Bartolucci, De Marchis and Malchiodi [Int. Math. Res. Not. 24, 5625-5643 (2011), 10.1093/imrn/rnq285].

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaudoin, B.; Haber, I.; Kishek, R. A.

An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifthmore » turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.« less

Longitudinal confinement and matching of an intense electron beam

NASA Astrophysics Data System (ADS)

Beaudoin, B.; Haber, I.; Kishek, R. A.; Bernal, S.; Koeth, T.; Sutter, D.; O'Shea, P. G.; Reiser, M.

2011-01-01

An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifth turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.

Parametric Study of Preferential Ion Heating Due to Intermittent Magnetic Fields in the Solar Wind

NASA Astrophysics Data System (ADS)

Carbajal Gomez, L.; Chapman, S. C.; Dendy, R. O.; Watkins, N. W.

2014-12-01

In situ observations and remote measurements of the solar wind show strong preferential heating of ions along the ambient magnetic field. Understanding the mechanism for this heating process is an open problem. The observed broad-band spectrum of Alfven waves permeating the fast solar wind provide a candidate mechanism for this preferential heating through wave-particle interactions on ion kinetic scales. Previous analytical and numerical studies have considered a single pump wave [1, 2] or a turbulent, broad-band spectra of Alfven waves [3, 4, 5] to drive the ion heating. The latter studies investigated the effects on ion heating due to different initial 1/fγpower spectral exponents and number of modes and the signals were random phase. However, the observed solar wind fluctuations are intermittent so that the phases of the modes comprising the power spectrum are not random. Non-Gaussian fluctuations are seen both on scales identified with the inertial range of Alfvenic turbulence [6], and on longer scales typified by '1/f' spectra [7]. We present results of the first parametric numerical simulations on the effects of different levels of intermittency of the broad-band spectra of Alfven waves on the preferential heating of ions in the solar wind. We performed hybrid simulations for the local heating of the solar wind, which resolves the full kinetic physics of the ions and treats the electrons as a charge-neutralizing fluid. Our simulations evolve the full vector velocities and electromagnetic fields in one configuration space coordinate and in time.We compare the efficiency of different levels of intermittency of the initial turbulent fields and their effect on the efficiency of the wave-particle interactions which are a mechanism for driving preferential ion heating in the solar wind. [1] J. A. Araneda, E. Marsh, A. F. Viñas, J. Geophys. Res. 112, A04104 (2007). [2] J. A. Araneda, E. Marsh, A. F. Viñas, Phys. Rev. Lett. 100, 125003 (2008) [3] Y. G. Maneva, A. F. Viñas, L. Ofman, J. Geophys. Res. 118, 2842 (2013). [4] L. Ofman, J. Geophys. Res. 115, 1461 (2010). [5] L. Ofman, S. P. Gary, A. Viñas, J. Geophys. Res. 107, 1461 (2002). [6] R. Bruno, V. Carbone, Living Rev. Solar Phys. 10, 2 (2013). [7] R. M. Nicol, S. C. Chapman, R. O. Dendy, The Astrophysical Journal 703, 2138 (2009).

The Encapsulation of Organic Molecules and Enzymes in Sol-Gel Glasses: Novel Photoactive, Optical, Sensing and Bioactive Materials. A Review

DTIC Science & Technology

1992-01-01

Fr.) 1976,1321. 2. Carturan. G .; Fachin. G4; Gottardi, V .; Guglicmi, M1; Movazio, GJ. Non-Cryst. Solids 1982., 4. 219. 23. Lopez. T.; Lopcz-Gaona. A...1976,44,739. 30. Shtelzer, S; Rappoport, S.; Avnir, D; Ottolenghi, M.; Braun, S., Bitech. Appi. Biochem., submitted 199L 3L Martinek, K, Mozhaev , V . V . Adv...Avnir, D4 Ottolcnighi, IM., J.Phys. C/Wffl. 1989, 93, 7544. & idem, Photrohent. Photobiol. 11ŕ, 54.525. 9. e- g ., (a) Gratzel, M. A"c. Chem. ReS

Tsallis non-additive entropy and natural time analysis of seismicity

NASA Astrophysics Data System (ADS)

Sarlis, N. V.; Skordas, E. S.; Varotsos, P.

2017-12-01

Within the context of Tsallis non-additive entropy [1] statistical mechanics -in the frame of which kappa distributions arise [2,3]- a derivation of the Gutenberg-Richter (GR) law of seismicity has been proposed [4,5]. Such an analysis leads to a generalized GR law [6,7] which is applied here to the earthquakes in Japan and California. These seismic data are also studied in natural time [6] revealing that although some properties of seismicity may be recovered by the non-additive entropy approach, temporal correlations between successive earthquake magnitudes should be also taken into account [6,8]. The importance of such correlations is strengthened by the observation of periods of long range correlated earthquake magnitude time series [9] a few months before all earthquakes of magnitude 7.6 or larger in the entire Japanese area from 1 January 1984 to 11 March 2011 (the day of the magnitude 9.0 Tohoku-Oki earthquake) almost simultaneously with characteristic order parameter variations of seismicity [10]. These variations appear approximately when low frequency abnormal changes of the electric and magnetic field of the Earth (less than around 1Hz) are recorded [11] before strong earthquakes as the magnitude 9.0 Tohoku-Oki earthquake in Japan in 2011 [12]. 1. C Tsallis, J Stat Phys 52 (1988) 479 2. G Livadiotis, and D J McComas, J Geophys Res 114 (2009) A11105 3. G Livadiotis, Kappa Distributions. (Elsevier, Amsterdam) 2017. doi: 10.1016/B978-0-12-804638-8.01001-9 4. O Sotolongo-Costa, A Posadas, Phys Rev Lett 92 (2004) 048501 5. R Silva, G França, C Vilar, J Alcaniz, Phys Rev E 73 (2006) 026102 6. N Sarlis, E Skordas, P Varotsos, Phys Rev E 82 (2010) 021110 7. L Telesca, Bull Seismol Soc Am 102 (2012) 886-891 8. P Varotsos, N Sarlis, E Skordas, Natural Time Analysis: The new view of time. (Springer, Berlin) 2011. doi: 10.1007/978-3-642-16449-1 9. P Varotsos, N Sarlis, E Skordas, J Geophys Res Space Physics 119 (2014) 9192. 10. N Sarlis, E Skordas, P Varotsos, T Nagao, M Kamogawa, H Tanaka, S Uyeda, Proc Natl Acad Sci USA 110 (2013) 13734. 11. P Varotsos, N Sarlis, E Skordas, M Lazaridou-Varotsos, Earthq Sci 30 (2017) doi: 10.1007/s11589-017-0189-0 12. P Varotsos, N Sarlis, E Skordas, Earthq Sci 30 (2017) doi: 10.1007/s11589-017-0182-7

Gender disparities in second-semester college physics: The incremental effects of a ``smog of bias''

NASA Astrophysics Data System (ADS)

Kost-Smith, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

2010-07-01

Our previous research [Kost , Phys. Rev. ST Phys. Educ. Res. 5, 010101 (2009)10.1103/PhysRevSTPER.5.010101] examined gender differences in the first-semester, introductory physics class at the University of Colorado at Boulder. We found that: (1) there were gender differences in several aspects of the course, including conceptual survey performance, (2) these differences persisted despite the use of interactive engagement techniques, and (3) the post-test gender differences could largely be attributed to differences in males’ and females’ prior physics and math performance and their incoming attitudes and beliefs. In the current study, we continue to characterize gender differences in our physics courses by examining the second-semester, electricity and magnetism course. We analyze three factors: student retention from Physics 1 to Physics 2, student performance, and students’ attitudes and beliefs about physics, and find gender differences in all three of these areas. Specifically, females are less likely to stay in the physics major than males. Despite males and females performing about equally on the conceptual pretest, we find that females score about 6 percentage points lower than males on the conceptual post-test. In most semesters, females outperform males on homework and participation, and males outperform females on exams, resulting in course grades of males and females that are not significantly different. In terms of students’ attitudes and beliefs, we find that both males and females shift toward less expertlike beliefs over the course of Physics 2. Shifts are statistically equal for all categories except for the Personal Interest category, where females have more negative shifts than males. A large fraction of the conceptual post-test gender gap (up to 60%) can be accounted for by differences in males’ and females’ prior physics and math performance and their pre-Physics 2 attitudes and beliefs. Taken together, the results of this study suggest that it is an accumulation of small gender differences over time that may be responsible for the large differences that we observe in physics participation of males and females.

A quantitative, comprehensive analytical model for ``fast'' magnetic reconnection in Hall MHD

NASA Astrophysics Data System (ADS)

Simakov, Andrei N.

2008-11-01

Magnetic reconnection in nature usually happens on fast (e.g. dissipation independent) time scales. While such scales have been observed computationally [1], a fundamental analytical model capable of explaining them has been lacking. Here, we propose such a quantitative model for 2D Hall MHD reconnection without a guide field. The model recovers the Sweet-Parker and the electron MHD [2] results in the appropriate limits of the ion inertial length, di, and is valid everywhere in between [3]. The model predicts the dissipation region aspect ratio and the reconnection rate Ez in terms of dissipation and inertial parameters, and has been found to be in excellent agreement with non-linear simulations. It confirms a number of long-standing empirical results and resolves several controversies. In particular, we find that both open X-point and elongated dissipation regions allow ``fast'' reconnection and that Ez depends on di. Moreover, when applied to electron-positron plasmas, the model demonstrates that fast dispersive waves are not instrumental for ``fast'' reconnection [4]. [1] J. Birn et al., J. Geophys. Res. 106, 3715 (2001). [2] L. Chac'on, A. N. Simakov, and A. Zocco, Phys. Rev. Lett. 99, 235001 (2007). [3] A. N. Simakov and L. Chac'on, submitted to Phys. Rev. Lett. [4] L. Chac'on, A. N. Simakov, V. Lukin, and A. Zocco, Phys. Rev. Lett. 101, 025003 (2008).

Antihydrogen Trapped in the ALPHA Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowe, Paul David

2011-02-25

In 2010 the ALPHA collaboration succeeded in trapping antihydrogen atoms for the first time.[i] Stored antihydrogen promises to be a unique tool for making high precision measurements of the structure of this first anti-atom. Achieving this milestone presented several substantial experimental challenges and this talk will describe how they were overcome. The unique design features of the ALPHA apparatus will be explained. These allow a high intensity positron source and an antiproton imaging detector similar to the one used in the ATHENA[iii] experiment to be combined with an innovative magnet design of the anti-atom trap. This seeks to minimise themore » perturbations to trapped charged particles which may cause particle loss and heating[iv]. The diagnostic techniques used to measure the diameter, number, density, and temperatures of both plasmas will be presented as will the methods developed to actively compress and cool of both plasma species to sizes and temperatures [v],[vi], [vii] where trapping attempts with a reasonable chance of success can be tried. The results of the successful trapping experiments will be outlined as well as some subsequent experiments to improve the trapping rate and storage time. [i] 'Trapped antihydrogen' G.B. Andresen et al., Nature 468, 673 (2010) [ii]'A Magnetic Trap for Antihydrogen Confinement' W. Bertsche et al., Nucl. Instr. Meth. Phys. Res. A566, 746 (2006) [iii] Production and detection of cold antihydrogen atoms M.Amoretti et al., Nature 419, 456 (2002). [iv]' Antihydrogen formation dynamics in a multipolar neutral anti-atom trap' G.B. Andresen et al., Phys. Lett. B 685, 141 (2010) [v]' Evaporative Cooling of Antiprotons to Cryogenic Temperatures', G.B. Andresen et al. Phys. Rev. Lett 105, 013003 (2010) [vi]'Compression of Antiproton Clouds for Antihydrogen Trapping' G. B. Andresen et al. Phys. Rev. Lett 100, 203401 (2008) [vii] 'Autoresonant Excitation of Antiproton Plasmas' G.B. Andresen et al., Phys. Rev. Lett. 106, 025002 (2011)« less

Antihydrogen Trapped in the ALPHA Experiment

ScienceCinema

Bowe, Paul David

2017-12-18

In 2010 the ALPHA collaboration succeeded in trapping antihydrogen atoms for the first time.[i] Stored antihydrogen promises to be a unique tool for making high precision measurements of the structure of this first anti-atom. Achieving this milestone presented several substantial experimental challenges and this talk will describe how they were overcome. The unique design features of the ALPHA apparatus will be explained. These allow a high intensity positron source and an antiproton imaging detector similar to the one used in the ATHENA[iii] experiment to be combined with an innovative magnet design of the anti-atom trap. This seeks to minimise the perturbations to trapped charged particles which may cause particle loss and heating[iv]. The diagnostic techniques used to measure the diameter, number, density, and temperatures of both plasmas will be presented as will the methods developed to actively compress and cool of both plasma species to sizes and temperatures [v],[vi], [vii] where trapping attempts with a reasonable chance of success can be tried. The results of the successful trapping experiments will be outlined as well as some subsequent experiments to improve the trapping rate and storage time. [i] 'Trapped antihydrogen' G.B. Andresen et al., Nature 468, 673 (2010) [ii]'A Magnetic Trap for Antihydrogen Confinement' W. Bertsche et al., Nucl. Instr. Meth. Phys. Res. A566, 746 (2006) [iii] Production and detection of cold antihydrogen atoms M.Amoretti et al., Nature 419, 456 (2002). [iv]' Antihydrogen formation dynamics in a multipolar neutral anti-atom trap' G.B. Andresen et al., Phys. Lett. B 685, 141 (2010) [v]' Evaporative Cooling of Antiprotons to Cryogenic Temperatures', G.B. Andresen et al. Phys. Rev. Lett 105, 013003 (2010) [vi]'Compression of Antiproton Clouds for Antihydrogen Trapping' G. B. Andresen et al. Phys. Rev. Lett 100, 203401 (2008) [vii] 'Autoresonant Excitation of Antiproton Plasmas' G.B. Andresen et al., Phys. Rev. Lett. 106, 025002 (2011)

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

DOE PAGES

Croft, S.; Cleveland, S.; Favalli, A.; ...

2018-02-23

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

Optimizing Nonlinear Beam Coupling in Low-Symmetry Crystals (Postprint)

DTIC Science & Technology

2014-10-02

Phys. Rev. E 55(1), 1035–1047 (1997). 9. Y. M. Vysochanskii and V. Y. Slivka, “ Ferroelectrics of the Sn2P2S6 family. Properties in Vicinity of Lifshitz...Standard on Piezoelectricity (IEEE, 1987), p. 242. 22. C. D. Carpentier and R. Nitsche, “ Ferroelectricity in Sn2P2S6,” Mater. Res. Bull. 9(8), 1097–1100...90 180 Θ , d e g -0.7 0.7 -180 -90 0 90 180 Θ , d e g -180 -90 0 90 180 j,deg -1. 1. Fig. 3. Pseudocolor 2D maps that represent normalized two-beam

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croft, S.; Cleveland, S.; Favalli, A.

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

Higher-Order Fermi-Liquid Corrections for an Anderson Impurity Away from Half Filling

NASA Astrophysics Data System (ADS)

Oguri, Akira; Hewson, A. C.

2018-03-01

We study the higher-order Fermi-liquid relations of Kondo systems for arbitrary impurity-electron fillings, extending the many-body quantum theoretical approach of Yamada and Yosida. It includes, partly, a microscopic clarification of the related achievements based on Nozières' phenomenological description: Filippone, Moca, von Delft, and Mora [Phys. Rev. B 95, 165404 (2017), 10.1103/PhysRevB.95.165404]. In our formulation, the Fermi-liquid parameters such as the quasiparticle energy, damping, and transport coefficients are related to each other through the total vertex Γσ σ';σ'σ(ω ,ω';ω',ω ), which may be regarded as a generalized Landau quasiparticle interaction. We obtain exactly this function up to linear order with respect to the frequencies ω and ω' using the antisymmetry and analytic properties. The coefficients acquire additional contributions of three-body fluctuations away from half filling through the nonlinear susceptibilities. We also apply the formulation to nonequilibrium transport through a quantum dot, and clarify how the zero-bias peak evolves in a magnetic field.

Higher-Order Fermi-Liquid Corrections for an Anderson Impurity Away from Half Filling.

PubMed

Oguri, Akira; Hewson, A C

2018-03-23

We study the higher-order Fermi-liquid relations of Kondo systems for arbitrary impurity-electron fillings, extending the many-body quantum theoretical approach of Yamada and Yosida. It includes, partly, a microscopic clarification of the related achievements based on Nozières' phenomenological description: Filippone, Moca, von Delft, and Mora [Phys. Rev. B 95, 165404 (2017)PRBMDO2469-995010.1103/PhysRevB.95.165404]. In our formulation, the Fermi-liquid parameters such as the quasiparticle energy, damping, and transport coefficients are related to each other through the total vertex Γ_{σσ^{'};σ^{'}σ}(ω,ω^{'};ω^{'},ω), which may be regarded as a generalized Landau quasiparticle interaction. We obtain exactly this function up to linear order with respect to the frequencies ω and ω^{'} using the antisymmetry and analytic properties. The coefficients acquire additional contributions of three-body fluctuations away from half filling through the nonlinear susceptibilities. We also apply the formulation to nonequilibrium transport through a quantum dot, and clarify how the zero-bias peak evolves in a magnetic field.

Quest for impact ignition and its future prospect

NASA Astrophysics Data System (ADS)

Murakami, Masakatsu; Azechi, H.; Watari, T.; Sakaiya, T.; Ohtani, K.; Takeda, K.; Shiraga, H.; Shigemori, K.; Fujioka, S.; Nagatomo, H.; Johzaki, T.; Gardner, J.; Bates, J.; Velikovich, A.; Aglitskiy, Y.; Karasik, M.; Weaver, J.; Obenschain, S.

2009-11-01

Since the impact ignition has been proposed [1], we have achieved such crucial milestones under the operation of Gekko XII (ILE) and NIKE (NRL) laser systems as super-high-velocity acceleration of foils ranging 700-1000 km/s and hundred-fold increase in neutron yield by impact collision [2]. For the latter achievement, the kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of 1.6 keV. The use of Bromine-doped plastic target are key measure to suppress Rayleigh-Taylor instabilities and thus to achieve effective collisions. Based on these preliminary results, we have done two-dimensional hydrodynamic simulations to demonstrate that ignition occurs when impactor with a velocity beyond 1500 km/s and a density of 50 g/cm3 collides with main fuel with a density of 400 g/cm3, when the maximum impactor kinetic energy is 10 kJ.[4pt] [1] M. Murakami and H. Nagatomo, Nucl. Inst. & Meth. Phys. Res. A544, 67 (2005).[0pt] [2] H. Azechi, et al., Phys. Rev. Lett. 102, 235002 (2009).

First Observation of ^60Ge and ^64Se

NASA Astrophysics Data System (ADS)

Stolz, Andreas

2004-10-01

The neutron-deficient nuclei ^60Ge and ^64Se were observed for the first time following the fragmentation of ^78Kr. This is the first observation of new proton-rich nuclei below Z=50 in over three years. A primary beam of 140-MeV/nucleon ^78Kr was produced using the Coupled Cyclotron Facility and fragmented in a Be target. The secondary neutron-deficient fragments were separated by the A1900 fragment separator [1] and stopped in a stack of silicon PIN diodes. The fragments were identified by a measurement of energy loss, total energy, and time-of-flight. ^60Ge is the last nucleus along the proton dripline lighter than cadmium which is predicted to be bound (S_2p = 50 ± 240 keV) by the latest atomic mass evaluation [2] and which has not yet been observed. Theoretical calculations predict ^60Ge to be bound with respect to two-proton emission by 167(141) keV [3] and 630 keV [4], while ^64Se is predicted not to be bound [2]. >From the number of observed events of ^60Ge and ^64Se the production cross section and lifetime will be estimated. No events of ^59Ga and ^63As were observed confirming that these nuclei are unbound with respect to proton emission and upper limits of the lifetime can be established. [1] D. J. Morrissey, B. M. Sherrill, M. Steiner, A. Stolz, and I. Wiedenhover, Nucl. Instrum. Methods Phys. Res. B 204, 90 (2003). [2] G. Audi, A. H. Wapstra, and C. Thibault, Nucl. Phys. A729, 337 (2003). [3] W. E. Ormand, Phys. Rev. C 55, 2407 (1997). [4] M.V. Stoitsov, J. Dobaczewski, W. Nazarewicz, S. Pittel, and D. J. Dean, Phys. Rev. C 68, 054312 (2003).

Should the Curricular Time Allocated to School Physical Education Be Increased? Insights from Participants in a Follow-up of the Trois-Rivières Study

ERIC Educational Resources Information Center

Larouche, Richard; Laurencelle, Louis; Shephard, Roy J.; Trudeau, François

2015-01-01

In this study, we explored the effects of exposure to an experimental program of daily physical education (PE) during primary school on adult attitudes toward school PE. In 2008, 86 original participants in the Trois-Rivières study (44 women and 42 men aged 44.0 ± 1.2 years) underwent a semistructured interview in which their attitudes toward PE,…

Natural hazards education in global environment leaders education programme for designing a low-carbon society

NASA Astrophysics Data System (ADS)

Lee, Han Soo; Yamashita, Takao; Fujiwara, Akimasa

2010-05-01

Global environmental leader (GEL) education programme at graduate school for international development and cooperation (IDEC) in Hiroshima University is an education and training programme for graduate students especially from developing countries in Asian region to build and enhance their ability to become international environmental leaders. Through this programme, they will participate in regular course works and other activities to learn how to cope with the various environment and resource management issues from global to regional scales toward a low-carbon society via multi-disciplinary approaches considering sustainable development and climate change. Under this GEL programme, there are five different research sub-groups as follows assuming a cause-effect relationship among interacting components of social, economic, and environmental systems; 1) urban system design to prevent global warming, 2) wise use of biomass resources, 3) environmental impact assessment, 4) policy and institutional design, and 5) development of environmental education programs. Candidate students of GEL programme belong to one of the five research sub-groups, perform their researches and participate in many activities under the cross-supervisions from faculty members of different sub-groups. Under the third research group for environmental impact assessment, we use numerical models named as regional environment simulator (RES) as a tool for research and education for assessing the environmental impacts due to natural hazards. Developed at IDEC, Hiroshima University, RES is a meso-scale numerical model system that can be used for regional simulation of natural disasters and environmental problems caused by water and heat circulation in the atmosphere, hydrosphere, and biosphere. RES has three components: i) atmosphere-surface waves-ocean part, ii) atmosphere-land surface process-hydrologic part, and iii) coastal and estuarine part. Each part is constructed with state-of-the-art public domain numerical models that are combined synchronously by an own-developed model coupler. Therefore, RES can provide detailed insights from various aspects of interaction processes between each component in the earth system. For instance, RES has been used for the study of storm surges and the abnormally high ocean waves caused by typhoons, cyclones, hurricanes, and winter monsoon winds in Asian region; dam lake circulation; air-sea interaction of momentum, heat, and tracer material exchange; heavy rainfall and runoff simulation; estuarine circulation with cohesive sediment transport; and wave overtopping in coastal regions. Most recently, a project on the impact of reduced discharge of freshwater and sediment from the Yangtze River basin on the adjacent East China Sea has been initiated by using the RES. Under the GEL programme, we found the RES can be an important and useful tool for graduate students not only from science and engineering background but also from social science so as to evaluate their policy and institutional design.

The ISOLDE facility

NASA Astrophysics Data System (ADS)

Catherall, R.; Andreazza, W.; Breitenfeldt, M.; Dorsival, A.; Focker, G. J.; Gharsa, T. P.; J, Giles T.; Grenard, J.-L.; Locci, F.; Martins, P.; Marzari, S.; Schipper, J.; Shornikov, A.; Stora, T.

2017-09-01

The ISOLDE facility has undergone numerous changes over the last 17 years driven by both the physics and technical community with a common goal to improve on beam variety, beam quality and safety. Improvements have been made in civil engineering and operational equipment while continuing developments aim to ensure operations following a potential increase in primary beam intensity and energy. This paper outlines the principal technical changes incurred at ISOLDE by building on a similar publication of the facility upgrades by Kugler (2000 Hyperfine Interact. 129 23-42). It also provides an insight into future perspectives through a brief summary issues addressed in the HIE-ISOLDE design study Catherall et al (2013 Nucl. Instrum. Methods Phys. Res. B 317 204-207).

The role of physics departments in the recruitment, preparation and support of pre-college teachers of physics

NASA Astrophysics Data System (ADS)

Seeley, Lane

2008-05-01

The United States faces a critical shortage of qualified physics and physical science teachers. The number of high school students taking physics is increasing but the number of physics majors pursuing careers in pre-college teaching is not nearly sufficient to meet the demand. College and university physics departments have content expertise and ready access to potential future teachers of physics. In order to address the crisis in physics and physical science education, APS, AAPT, and AIP have developed the PhysTEC project. Seattle Pacific University is one of six fully funded PhysTEC sites. The PhysTEC project also supports a coalition of more than one hundred institutions that are committed to improving K-12 physics and physical science education. This talk will describe the national PhysTEC project along with our local PhysTEC program. We will explore ways in which physics departments can more fully integrate the preparation of pre-college physics teachers within existing departmental priorities. We will discuss opportunities for regional partnerships between 2-year and 4-year colleges, school districts, and teacher preparation programs. We will also highlight ways in which our research on the learning and teaching of physics informs the development of tools that teachers and teacher educators can use to diagnose student ideas and to design subsequent instruction that capitalizes on these ideas. In collaboration with Stamatis Vokos, Seattle Pacific University and Pam Kraus, Facet Innovations LLC.

Teacher beliefs and cultural models: A challenge for science teacher preparation programs

NASA Astrophysics Data System (ADS)

Bryan, Lynn A.; Atwater, Mary M.

2002-11-01

The purpose of this paper is to present an argument for developing science teacher education programs that examine teachers' beliefs about multicultural issues and their impact on science teaching and learning. In the paper, we (a) delineate a rationale for the study of teacher beliefs about issues of culture and its impact on science teaching and learning; (b) assert three major categories of teacher beliefs to examine for designing teacher education programs that aim to meet the challenges of increasingly culturally diverse classrooms; and (c) discuss implications for science teacher education programs and research. Research has shown that knowing teachers' beliefs and designing instruction and experiences to explicitly confront those beliefs facilitate refinement of and/or transformation of beliefs and practices (Bryan & Abell, J Res Sci Teaching, 36, 121-140, 1999; Harrington & Hathaway, J Teacher Education, 46, 275-284, 1995; Hollingsworth, Am Educational Res J, 26(2), 160-189, 1989; Olmedo, J Teaching Teacher Education, 13, 245-258, 1997; Tobin & LaMaster, J Res Sci Teaching, 32, 225-242, 1995). Furthermore, prior to student teaching, preservice teachers need to be at least culturally sensitive teachers (Gillette, In Teacher Thinking in Cultural Contexts, F. A. Rios (Ed.); Albany, NY: State University of New York Press; 1996, pp. 104-128). Science educators need to continue to identify those beliefs and practices that undergird desirable and equitable science instruction.

PERSPECTIVE: Snow matters in the polar regions

NASA Astrophysics Data System (ADS)

Sodeau, John

2010-03-01

Antarctica is not quite as chemically pristine as might sometimes be thought (Jones et al 2008). For example, as elsewhere, reduced sulfur species such as dimethylsulfide (DMS) are emitted from biogenic marine sources at the poles (Read et al 2008). Somewhat less well known is that inland (as opposed to coastal) field campaigns have also detected, within the Antarctic boundary layer (ABL), emissions containing unexpectedly high levels of diverse, oxidizing chemicals such as NOx, nitrate ions, formaldehyde, ozone and hydrogen peroxide (Honrath et al 1999, Hutterli et al 2004, Sumner and Shepson 1999). And then there are the halogen-containing compounds (Simpson et al 2007). The transformation of DMS to sulfate aerosols capable of acting as cloud condensation nuclei often proceeds via one main oxidized product of DMS, namely methanesulfonic acid (MSA). Two specific reactions have been well studied to date in this regard, namely DMS plus either OH or NO3 radicals. Corresponding reactions with halogen radicals, which also contribute to the oxidizing capacity of our atmosphere, have generally been considered to be of less importance. The reason for this view is that even though the reactivity of bromine- and iodine-containing radicals is much greater than that of OH, the halogens were thought to be relatively scarce in the polar atmosphere. However both BrO (and IO) have been detected in the Antarctic CHABLIS campaign, as discussed in depth in the Atmospheric Chemistry and Physics special issue of 2008, see Jones et al (2008). It was subsequently shown that calculated MSA production from the DMS/BrO reaction may be about an order of magnitude greater than when the OH radical was the oxidizing reactant. The recent analytical measurements by Antony et al (2010) of MSA, Br and NO3 found in snow along the Ingrid Christensen Coast of East Antarctica are important in the above field context. Hence it would appear that the concentrations of these ions in ice-cap sites are up to 30 times greater than those found in ice-free areas. The main question to ask is: how might the bromine have become released to the atmosphere? Many ideas have, in fact, been put forward over the last few years as to how such polar ocean-troposphere exchanges can take place. Much of the interest was driven by the so-called 'sudden' ozone depletion episodes first detected in Arctic air during the 1990s alongside simultaneous bromine 'explosions' which were monitored by ground-based instrumentation and satellite (as the radical BrO) over sea-ice covered by snowpack (Hausmann and Platt 1994, Schonhardt et al 2008). The likely precursors suggested, to date, have been sea-salt, frost-flowers and anthropogenic contents rather than organo- bromine matter (Simpson et al 2007). Associated processing routes including the formation of HOBr, the need for acidity, the involvement of trihalide ions and the potential role of freezing processes and the quasi-liquid layer have all been discussed in this context (Abbatt 1994, Neshyba et al 2009, O'Driscoll et al 2006). Computational work has also led to suggestions that preferential surface dispersion of the more highly polarizable halides (iodide and bromide ions) may lead to their direct interfacial reaction with atmospheric ozone leading to BrO or IO formation (Jungwirth and Winter 2008). The involvement of snow micro-algae in the production of halo-compounds such as CHBr3 and CH2Br2 in Antarctica cannot, of course, be ignored following the measurement of these compounds by Sturges and co-workers over 15 years ago (Sturges et al 1993). And the measurement of high levels of nutrient discussed in the recent work by Antony et al (2010) in the ice-cap areas do provide a basis for understanding why micro- algae growth in snow might be promoted. However the question still comes back to: how are these halo-compounds processed to produce 'active' species like BrO radicals, HOBr, Br atoms, Br2 gas or interhalogens such as BrCl? The relatively long history of this topic was surveyed extensively in 2007 and the answer is probably not related to the photolysis of the halogeno-carbons although the transformation processes are still not completely understood (Simpson et al 2007). This topic along with the potential involvement of both iodine and chlorine species is decidedly 'hot' in the intriguing world of polar cryochemistry. The Antony et al (2010) paper is actually entitled 'Is cloud seeding in coastal Antarctica linked to bromine and nitrate variability in snow?'. Although the nitrate ions were discussed in terms of being a simple nutrient in the study, the photochemistry of nitrate ions in snow has actually become an important focus of research in the laboratory. A further review by Grannas et al (2007) is recommended in this respect. But important questions remain regarding the fate of the NO and NO2 molecules produced in the primary photolytic channels, especially if concentrated into ice 'micropockets' (Hellebust et al 2007). Furthermore the impacts of newly discovered reactions such as HO2/NO to directly produce nitric acid, at the expense of NOx, have not yet been quantified in the polar ABL context (Cariolle et al 2008). Then there is peroxyacetylnitrate (PAN; Mills et al 2007) and other organo-nitrates and their possible interactions with mercury and the halides . . . Clearly, Antarctica is not chemically pristine and snow-ice interfaces in both the laboratory and the field have become a very challenging medium for exploring new and unexpected chemistry relevant to our atmosphere. References Abbatt J P D 1994 Heterogeneous reaction of HOBr with HBr and HCl on ice surfaces at 228 K Geophys. Res. Lett. 21 665-8 Antony R et al 2010 Is cloud seeding in coastal Antarctica linked to bromine and nitrate variability in snow? Environ. Res. Lett. 5 014009 Cariolle D et al 2008 Impact of the new HNO3-forming channel of the HO2 + NO reaction on tropospheric HNO3, NOx, HOx and ozone Atmos. Chem. Phys. 8 4061-8 Grannas A M et al 2007 An overview of snow photochemistry: evidence, mechanisms and impacts Atmos. Chem. Phys. 7 4329-73 Hausmann M and Platt U 1994 Spectroscopic measurement of bromine oxide and ozone in the high Arctic during polar sunrise experiment 1992 J. Geophys. Res. Atmos. 99 25399-413 Hellebust S et al 2007 Potential role of the nitroacidium ion on HONO emissions from the snowpack J. Phys. Chem. A 111 1167-71 Honrath R et al 1999 Evidence of NOx production within or upon ice particles in the Greenland snowpack Geophys. Res. Lett. 26 695-8 Hutterli M A et al 2004 Formaldehyde and hydrogen peroxide in air, snow and interstitial air at South Pole Atmos. Environ. 38 5439-50 Jones A E et al 2008 Chemistry of the Antarctic boundary layer and the interface with snow: an overview of the CHABLIS campaign Atmos. Chem. Phys. 8 3789-803 Jungwirth P and Winter B 2008 Ions at aqueous interfaces: from water surface to hydrated proteins Ann. Rev. Phys. Chem. 59 343-66 Mills G P et al 2007 Seasonal variation of peroxyacetylnitrate (PAN) in coastal Antarctica measured with a new instrument for the detection of sub-part per trillion mixing ratios of PAN Atmos. Chem. Phys. 7 4589-99 Neshyba S et al 2009 Molecular dynamics study of ice-vapor interactions via the quasi-liquid layer J. Phys. Chem. C 113 4597-604 O'Driscoll P et al 2006 Freezing halide ion solutions and the release of interhalogens to the atmosphere J. Phys. Chem. A 110 4615-8 Read K A et al 2008 DMS and MSA measurements in the Antarctic boundary layer: impact of BrO on MSA production Atmos. Chem. Phys. 8 2985-97 Schonhardt A et al 2008 Observations of iodine monoxide columns from satellite Atmos. Chem. Phys. 8 637-53 Simpson W R et al 2007 Halogens and their role in polar boundary-layer ozone depletion Atmos. Chem. Phys. 7 4375-418 Sturges W T et al 1993 Spring measurements of tropospheric bromine at Barrow, Alaska Geophys. Res. Lett. 20 201-4 Sumner A L and Shepson P B 1999 Snowpack production of formaldehyde and its effect on the Arctic troposphere Nature 398 230-3

Charging and performance of the CubeSTAR satellite studied by numerical simulations

NASA Astrophysics Data System (ADS)

Miloch, Wojciech; Bekkeng, Tore André; Lindem, Torfinn

2012-07-01

A good understanding of spacecraft-plasma interaction is important for all space missions and experiments. The spacecraft potential is determined by the plasma, photoemission and other currents [1]. A charged object can significantly disturb the surrounding plasma, and lead to wake formation. The wake features, such as ion focusing, can influence the measurements of the plasma by the instruments onboard. A study of this problem using analytical models is difficult and can not account for all phenomena. This has encouraged use of numerical models for self-consistent studies of the plasma-object interactions on a detailed kinetic level [2][3]. With three-dimensional particle-in-cell (PIC) simulations [3][4], we address the spacecraft-plasma interaction in various plasma environments, and account for the self-consistent charging of the spacecraft by plasma and photoemission currents. As a specific case, we consider the interactions between plasma and a CubeSTAR satellite. CubeSTAR is a nano-satellite for the space weather studies being constructed in Norway, with the launch scheduled for year 2013. With a novel Langmuir probe system [5], it will measure the absolute electron densities with a high spatial resolution, allowing for studies of small scale plasma irregularities. We perform a systematic study of the role of the wakefield on the measurements with the Langmuir probes onboard the CubeSTAR for the plasma conditions relevant for the planned polar orbit. The simulation results are of relevance also for other spacecraft missions. [1] Whipple E C, Rep. Prog. Phys. 44, 1197 (1981). [2] Roussel J F and Berthelier J J, J. Geophys. Res. 109, A01104 (2004). [3] Yaroshenko V V et al., J. Geophys. Res. 116, A12218 (2011). [4] Miloch W J Kroll M and Block D 2010 Phys. Plasmas 17, 103703 (2010). [5] Bekkeng T A et al. Meas. Sci. Technol. 21, 085903 (2010).

Simulations of electron transport and ignition for direct-drive fast-ignition targets

NASA Astrophysics Data System (ADS)

Solodov, A. A.; Anderson, K. S.; Betti, R.; Gotcheva, V.; Myatt, J.; Delettrez, J. A.; Skupsky, S.; Theobald, W.; Stoeckl, C.

2008-11-01

The performance of high-gain, fast-ignition fusion targets is investigated using one-dimensional hydrodynamic simulations of implosion and two-dimensional (2D) hybrid fluid-particle simulations of hot-electron transport, ignition, and burn. The 2D/3D hybrid-particle-in-cell code LSP [D. R. Welch et al., Nucl. Instrum. Methods Phys. Res. A 464, 134 (2001)] and the 2D fluid code DRACO [P. B. Radha et al., Phys. Plasmas 12, 056307 (2005)] are integrated to simulate the hot-electron transport and heating for direct-drive fast-ignition targets. LSP simulates the transport of hot electrons from the place where they are generated to the dense fuel core where their energy is absorbed. DRACO includes the physics required to simulate compression, ignition, and burn of fast-ignition targets. The self-generated resistive magnetic field is found to collimate the hot-electron beam, increase the coupling efficiency of hot electrons with the target, and reduce the minimum energy required for ignition. Resistive filamentation of the hot-electron beam is also observed. The minimum energy required for ignition is found for hot electrons with realistic angular spread and Maxwellian energy-distribution function.

PhysDoc: A Distributed Network of Physics Institutions: Collecting, Indexing, and Searching High Quality Documents by Using Harvest; The Dublin Core Metadata Initiative: Mission, Current Activities, and Future Directions; Information Services for Higher Education: A New Competitive Space; Intellectual Property Conservancies.

ERIC Educational Resources Information Center

Severiens, Thomas; Hohlfeld, Michael; Zimmermann, Kerstin; Hilf, Eberhard R.; von Ossietzky, Carl; Weibel, Stuart L.; Koch, Traugott; Hughes, Carol Ann; Bearman, David

2000-01-01

Includes four articles that discuss a variety to topics, including a distributed network of physics institutions documents called PhysDocs which harvests information from the local Web-servers of professional physics institutions; the Dublin Core metadata initiative; information services for higher education in a competitive environment; and…

Cross Calibration of Omnidirectional Orbital Neutron Detectors of Lunar Prospector (LP) and Lunar Exploration Neutron Detector (LEND) by Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Murray, J.; SU, J. J.; Sagdeev, R.; Chin, G.

2014-12-01

Introduction:Monte Carlo (MC) simulations have been used to investigate neutron production and leakage from the lunar surface to assess the composition of the lunar soil [1-3]. Orbital measurements of lunar neutron flux have been made by the Lunar Prospector Neutron Spectrometer (LPNS)[4] of the Lunar Prospector mission and the Lunar Exploration Neutron Detector (LEND)[5] of the Lunar Reconnaissance Orbiter mission. While both are cylindrical helium-3 detectors, LEND's SETN (Sensor EpiThermal Neutrons) instrument is shorter, with double the helium-3 pressure than that of LPNS. The two instruments therefore have different angular sensitivities and neutron detection efficiencies. Furthermore, the Lunar Prospector's spin-stabilized design makes its detection efficiency latitude-dependent, while the SETN instrument faces permanently downward toward the lunar surface. We use the GEANT4 Monte Carlo simulation code[6] to investigate the leakage lunar neutron energy spectrum, which follows a power law of the form E-0.9 in the epithermal energy range, and the signals detected by LPNS and SETN in the LP and LRO mission epochs, respectively. Using the lunar neutron flux reconstructed for LPNS epoch, we calculate the signal that would have been observed by SETN at that time. The subsequent deviation from the actual signal observed during the LEND epoch is due to the significantly higher intensity of Galactic Cosmic Rays during the anomalous Solar Minimum of 2009-2010. References: [1] W. C. Feldman, et al., (1998) Science Vol. 281 no. 5382 pp. 1496-1500. [2] Gasnault, O., et al.,(2000) J. Geophys. Res., 105(E2), 4263-4271. [3] Little, R. C., et al. (2003), J. Geophys. Res., 108(E5), 5046. [4]W. C. Feldman, et al., (1999) Nucl. Inst. And Method in Phys. Res. A 422, [5] M. L. Litvak, et al., (2012) J.Geophys. Res. 117, E00H32 [6] J. Allison, et al, (2006) IEEE Trans. on Nucl Sci, Vol 53, No 1.

3D modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn

NASA Astrophysics Data System (ADS)

Pérez-Invernón, Francisco J.; Luque, Alejandro; Gordillo-Vázquez, Francisco J.

2017-04-01

Atmospheric electricity is a common phenomenon in some planets of The Solar System. We know that atmospheric discharges exist on Earth and gaseous planets; however, some characteristics of lightning on Saturn and Jupiter as well as their relevance on the effects of lightning in the atmospheres of these planets are still unknown. In the case of Venus, there exist some radio evidences of lightning, but the lack of optical observations suggests exploring indirect methods of detection, such as searching for lightning-induced transient optical emissions from the upper atmosphere. The Akatsuki probe, currently orbiting Venus, is equipped with a camera whose temporal resolution is high enough to detect optical emissions from lightning discharges and to measure nightglow enhancements. In this work, we extend previous models [1,2] to investigate the chemical impact and transient optical emissions produced by possible lightning-emitted electromagnetic pulses (EMP) in Venus, Saturn and Jupiter. Using a 3D FDTD ("Finite Differences Time Domain") model we solve the Maxwell equations coupled with the Langevin equation for electrons [3] and with a kinetic scheme, different for each planetary atmosphere. This method is useful to investigate the temporal and spatial impact of lightning-induced electromagnetic fields in the atmosphere of each planet for different lightning characteristics (e.g. energy released, orientation). This 3D FDTD model allows us to include the saturnian and jovian background magnetic field inclination and magnitude at different latitudes, and to determine the effects of different lightning channel inclinations. Results provide useful information to interpret lightning observations on giant gaseous planets and in the search for indirect optical signals from atmospheric discharge on Venus such as fast nightglow transient enhancements related to lightning as seen on Earth. Furthermore, we underline the observation of electrical discharges characteristics as a powerful tool to obtain information about planetary atmospheres, such as density profiles of electrons or other components. Our model may also be useful to extend some studies about the chemical impact of EMP pulses in the terrestrial atmosphere [4]. References [1] Luque, A., D. Dubrovin, F. J. Gordillo-Vázquez, U. Ebert, F. C. Parra-Rojas, Y. Yair, and C. Price (2014), Coupling between atmospheric layers in gaseous giant planets due to lightning-generated electromagnetic pulses, J. Geophys. Res. (Space Phys), 119, 8705, doi: 10.1002/2014JA020457. [2] Pérez-Invernón, F. J., A. Luque, and F. J. Gordillo-Vázquez (2016), Mesospheric optical signatures of possible lightning on Venus, J. Geophys. Res. (Space Phys), 121, 7026, doi: 10.1029/2016JA022886. [3] Lee, J. H., and D. K. Kalluri (1999), Three-dimensional FDTD simulation of electromagnetic wave transformation in a dynamic inhomogeneous magnetized plasma, IEEE Transactions on Antennas and Propagation, 47, 1146, doi:10.1109/8.785745. [4] Marshall, R. A., U. S. Inan, and V. S. Glukhov (2010), Elves and associated electron density changes due to cloud-to-ground and in-cloud lightning discharges, J. Geophys. Res. (Space Phys), 115, A00E17, doi:10.1029/2009JA014469.

Improving Science Teacher Preparation through the APS PhysTEC and NSF Noyce Programs

NASA Astrophysics Data System (ADS)

Williams, Tasha; Tyler, Micheal; van Duzor, Andrea; Sabella, Mel

2013-03-01

Central to the recruitment of students into science teaching at a school like CSU, is a focus on the professional nature of teaching. The purpose of this focus is twofold: it serves to change student perceptions about teaching and it prepares students to become teachers who value continued professional development and value the science education research literature. The Noyce and PhysTEC programs at CSU place the professional nature of teaching front and center by involving students in education research projects, paid internships, attendance at conferences, and participation in a new Teacher Immersion Institute and a Science Education Journal Reading Class. This poster will focus on specific components of our teacher preparation program that were developed through these two programs. In addition we will describe how these new components provide students with diverse experiences in the teaching of science to students in the urban school district. Supported by the NSF Noyce Program (0833251) and the APS PhysTEC Program.

Mitigating chromatic effects for the transverse focusing of intense charged particle beams

NASA Astrophysics Data System (ADS)

Mitrani, James; Kaganovich, Igor; Davidson, Ronald

2013-09-01

A final focusing scheme designed to minimize chromatic effects is discussed. Solenoids are often used for transverse focusing in accelerator systems that require a charged particle beam with a small focal spot and/or large energy density A sufficiently large spread in axial momentum will reduce the effectiveness of transverse focusing, and result in chromatic effects on the final focal spot. Placing a weaker solenoid upstream of a stronger final focusing solenoid (FFS) mitigates chromatic effects on transverse beam focusing. J.M. Mitrani et al., Nucl. Inst. Meth. Phys. Res. A (2013) http://dx.doi.org/10.1016/j.nima.2013.05.09 This work was supported by DOE contract DE-AC02-09CH11466.

Corrigendum to "Energy-correction photon counting pixel for photon energy extraction under pulse pile-up" [Nucl. Instrum. Methods Phys. Res. A 856 (2017) 36-46

NASA Astrophysics Data System (ADS)

Lee, Daehee; Park, Kyungjin; Lim, Kyung Taek; Cho, Gyuseong

2018-03-01

The authors regret to inform the editorial office that the name for one of the co-authors in the article requires a correction. The co-author's name should be changed from 'Kyungjin Park' to 'Kyeongjin Park'. We would like to emphasize that 'Kyungjin Park' and 'Kyeongjin Park' belong to the identical person. However, 'Kyeongjin Park' is the official spelling on other published journals and his passport. There has been a miscommunication among the authors on the pronunciation for 'Kyeongjin Park' when we were translating his name from Korean to English. Therefore, the author's name spelling needs to be changed from 'Kyungjin Park' to 'Kyeongjin Park.'

Corrigendum to 'A new cross-detection method for improved energy-resolving photon counting under pulse pile-up' [Nucl. Instrum. Methods Phys. Res. A 867 (2017) 154-162

NASA Astrophysics Data System (ADS)

Lee, Daehee; Lim, Kyung Taek; Park, Kyungjin; Lee, Changyeop; Cho, Gyuseong

2018-03-01

The authors regret to inform the editorial office that the name for one of the co-authors in the article requires a correction. The co-author's name should be changed from 'Kyungjin Park' to 'Kyeongjin Park'. We would like to emphasize that 'Kyungjin Park' and 'Kyeongjin Park' belong to the identical person. However, 'Kyeongjin Park' is the official spelling on other published journals and his passport. There has been a miscommunication among the authors on the pronunciation for 'Kyeongjin Park' when we were translating his name from Korean to English. Therefore, the author's name spelling needs to be changed from 'Kyungjin Park' to 'Kyeongjin Park.'

Manpower Education in a Growing Economy.

ERIC Educational Resources Information Center

Darcy, Robert L.; Powell, Phillip E.

This publication provides an introduction to manpower education and presents a summary report on a 2-year res"arch and curriculum development project for manpower and economic education at the junior high school level. The introduction includes "The Meaning of Manpower Education" and "Major Themes for A Manpower Education Course" which outlines…

Immersion freezing by SnomaxTM particles: Comparison of results from different instruments

NASA Astrophysics Data System (ADS)

Wex, Heike; Stratmann, Frank; Rösch, Michael; Niedermeier, Dennis; Nilius, Björn; Möhler, Ottmar; Mitra, Subir K.; Koop, Thomas; Jantsch, Evelyn; Hiranuma, Naruki; Diehl, Karoline; Curtius, Joachim; Budke, Carsten; Boose, Yvonne; Augustin, Stefanie

2014-05-01

Within the DFG funded research unit INUIT (Ice Nucleation research UnIT, FOR 1525), an effort was made to compare results on immersion freezing from a suite of different instruments. Besides mineral dusts, SnomaxTM was picked as one of the substances that were examined by all participating groups. Here, the comparison of the results for SnomaxTM is presented. Every participating group used SnomaxTM from the same batch and, as far as possible, the same particle generation set-up. Instruments participating in the comparison were, in alphabetical order, an acoustic levitator (Diehl et al., 2009), AIDA (Connolly et al., 2009), BINARY (Budke et al., 2013), FINCH (Bundke et al., 2008), LACIS (Hartmann et al., 2011), PINC (Chou et al., 2011) and the Mainz vertical windtunnel (Diehl et al., 2011). Some of the instruments examined droplets directly produced from SnomaxTM suspensions, where the suspensions could have a wide range of concentrations. Other instruments used size segregated particles which were generated via atomization from a SnomaxTM suspension and subsequent drying, followed by size selection with a DMA (Differential Mobility Analyzer). These particles were then activated to droplets and cooled subsequently. For these, the number of ice nucleation active protein complexes present in the droplets depended on the original particle size (for details see e.g. Hartmann et al., 2013). Also, the different measurements spanned a range of different time scales. The shortest residence time of roughly 1 second was used for LACIS measurements, and the longest one was about 6 seconds used in the BINARY setup with a cooling rate of 1 K/min. All data were evaluated using two different approaches: 1) a time dependent approach following Classical Nucleation Theory which included the use of a contact angle distribution (see Niedermeier et al., 2014); 2) a singular approach using an active site density per mass (see Vali, 1971, Murray et al., 2012). Both approaches were found to work equally well, hence freezing by SnomaxTM can be considered to show no time dependence. Particularly data from LACIS and BINARY, i.e. from the "fastest" and "slowest" measurements, were found to agree very well. Acknowledgement: This work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525). Literature Budke et al. (2013), Investigation of Heterogeneous Ice Nucleation Using a Novel Optical Freezing Array, AIP Conference Proceedings, 1527, 949-951, doi: 10.1064/1.4803429. Bundke et al. (2008), The fast Ice Nucleus chamber FINCH, Atmos. Res. 90, 180-186. Chou et al. (2011), Ice nuclei properties within a Saharan dust event at the Jungfraujoch in the Swiss Alps, Atmos. Chem. Phys., 11, 4725-4738. Connolly, et al. (2009), Studies of heterogeneous freezing by three different desert dust samples, Atmos. Chem. Phys., 9, 2805-2824. Diehl et al. (2011), The Mainz vertical wind tunnel facility: A review of 25 years of laboratory experiments on cloud physics and chemistry. In: J.D. Pereira (Ed.), Wind tunnels: Aerodynamics, models, and experiments. Nova Science Publishers, Inc., Chapter 2. Diehl et al. (2009), Homogeneous freezing of single sulfuric and nitric acid solution drops levitated in an acoustic trap, Atm. Res., 94, 356-361, doi:10.1016/j.atmosres.2009.06.001. Hartmann et al. (2011), Homogeneous and heterogeneous ice nucleation at LACIS: Operating principle and theoretical studies, Atmos. Chem. Phys., 11, 1753-1767. Hartmann et al. (2013), Immersion freezing of ice nucleating active protein complexes, Atmos. Chem. Phys., 13, 5751-5766. Murray et al. (2012), Ice nucleation by particles immersed in supercooled cloud droplets, Chem. Soc. Rev., 41, 6519-6554. Niedermeier et al. (2014), A computationally-efficient description of heterogeneous freezing: A simplified version of the Soccer ball model, Geophys. Res. Lett., 10.1002/2013GL058684. Vali, G. (1971), Quantitative evaluation of experimental results on heterogeneous freezing nucleation of supercooled liquids, J. Atmos. Sci., 28(3), 402-409.

The analysis of senior high school students' physics HOTS in Bantul District measured using PhysReMChoTHOTS

NASA Astrophysics Data System (ADS)

Istiyono, Edi

2017-08-01

The purpose of this research is to describe the results of higher order thinking skills in physics (PhysHOTS) measurement including: (1) percentage of PhysHOTS level and (2) percentage of the domination of response in the category of students in each analyzing, evaluating, and creating skill. There were 404 10th grade students in Bantul District as the respondents of this research. The instrument used for measurement was PhysReMChoTHOTS. It was divided into two sets consisting of 44 items and including 8 anchor items stated valid by a Physicist, Physics Education Expert, and Physics Education Measurement Expert. The instrument was fit to PCM. The reliability coefficient of this test is 0.71, while the difficulty index of the items ranges from -0.61 to 0.51. The results of the measurement show that: (1) The percentage of each category of PhysHOTS for the 10th grade students in Bantul District for the very low, low, medium, high, and very high category is 4.75 %, 40.30 %, 33.45 %, 19.50 %, and 2.00 %, respectively; and (2) The order in analyzing skills, starts from the weakest, is attributing, differentiating and organizing. The order in evaluating skills, starts from the weakest, is critiquing and checking. Meanwhile, the order in creating skills, starts from the weakest, is producing, planning, and generating.

Melting curve of materials: theory versus experiments

NASA Astrophysics Data System (ADS)

Alfè, D.; Vocadlo, L.; Price, G. D.; Gillan, M. J.

2004-04-01

A number of melting curves of various materials have recently been measured experimentally and calculated theoretically, but the agreement between different groups is not always good. We discuss here some of the problems which may arise in both experiments and theory. We also report the melting curves of Fe and Al calculated recently using quantum mechanics techniques, based on density functional theory with generalized gradient approximations. For Al our results are in very good agreement with both low pressure diamond-anvil-cell experiments (Boehler and Ross 1997 Earth Planet. Sci. Lett. 153 223, Hänström and Lazor 2000 J. Alloys Compounds 305 209) and high pressure shock wave experiments (Shaner et al 1984 High Pressure in Science and Technology ed Homan et al (Amsterdam: North-Holland) p 137). For Fe our results agree with the shock wave experiments of Brown and McQueen (1986 J. Geophys. Res. 91 7485) and Nguyen and Holmes (2000 AIP Shock Compression of Condensed Matter 505 81) and the recent diamond-anvil-cell experiments of Shen et al (1998 Geophys. Res. Lett. 25 373). Our results are at variance with the recent calculations of Laio et al (2000 Science 287 1027) and, to a lesser extent, with the calculations of Belonoshko et al (2000 Phys. Rev. Lett. 84 3638). The reasons for these disagreements are discussed.

Thermodynamic and Thermoelastic properties of the NAL Phase

NASA Astrophysics Data System (ADS)

Marcondes, M. L.; Yao, C.; Wu, Z.; Wentzcovitch, R.

2017-12-01

Subduction of Mid Ocean Ridge Basalt (MORB) transports crust elements to the deep Earth. Therefore, it is important to study MORB in order to understand geophysical processes in the mantle. The high Al2O3 content of the MORB gives rise to a new aluminous phase (NAL) that constitutes up to 25% of its composition [1]. Phase equilibrium study of MgAl2O4-CaAl2O4 generated the mineral CaMg2Al6O12 with hexagonal symmetry, which was proposed for the NAL phase [2,3]. The NAL chemical composition, however, shows significantly less calcium [1,4] and several compositions have been considered in previous studies of this phase [5,6]. Here we present an ab initio study of NAL phases at high temperatures with several possible compositions. We used the quasiharmonic approximation to address thermodynamic and thermoelastic properties and seismic velocities of this phase as function of composition. References[1] T. Irifune and A. E. Ringwood, Earth Planet. Sci. Lett. 117, 101 (1993). [2] H. Miura, Y. Hamada, T. Suzuki, M. Akaogi, N. Miyajima, and K. Fujino, Am. Mineral. 85, 1799 (2000). [3] M. Akaogi, Y. Hamada, T. Suzuki, M. Kobayashi, and M. Okada, Phys. Earth Planet. Inter. 115, 67 (1999). [4] A. Ricolleau, J. P. Perrillat, G. Fiquet, I. Daniel, J. Matas, A. Addad, N. Menguy, H. Cardon, M. Mezouar, and N. Guignot, J. Geophys. Res. Solid Earth 115, B08202 (2010). [5] M. Mookherjee, B. B. Karki, L. Stixrude, and C. Lithgow-Bertelloni, Geophys. Res. Lett. 39, L19306 (2012). [6] K. Kawai and T. Tsuchiya, Geophys. Res. Lett. 37, L17302 (2010).

Scaling of Convective Mixing in CO2 sequestration}

NASA Astrophysics Data System (ADS)

Hidalgo, J. J.; Cueto-Felgueroso, L.; Fe, J.; Juanes, R.

2012-12-01

Dissolution by convective mixing is a key trapping mechanisms during CO2 sequestration in saline aquifers. It is caused by a Rayleigh-Bénard-type instability resulting from the higher density CO2-brine mixture overlaying the resident brine. During the time period before the convective fingers reach the bottom of the aquifer, the Rayleigh number Ra is not a parameter that describes the system [Hidalgo & Carrera (2009), J. Fluid Mech.; Slim & Ramakrishnan (2010), Phys. Fluids], which suggests that dissolution fluxes should not depend on Ra. However, this appears to be in contradiction with recent experimental results using an analogue-fluid system characterized by a non-monotonic density-concentration curve, which naturally undergoes convection [Neufeld et al. (2010), Geophys. Res. Lett.; Backhaus, Turitsyn & Ecke (2011), Phys. Rev. Lett.]. Here we study the scaling of dissolution fluxes by means of the variance of concentration and the scalar dissipation rate. The fundamental relations among these three quantities allow us to study the canonical and analogue-fluid systems with high-resolution numerical simulations, and to demonstrate that both the canonical and analogue-fluid systems exhibit a dissolution flux that is constant and independent of Ra. Our findings point to the need for alternative explanations of recent nonlinear scalings of the Nusselt number observed experimentally.

Measurements of Turbulent Transport of Fast Ions in the LAPD

NASA Astrophysics Data System (ADS)

Zhang, Y.; Boehmer, H.; Heidbrink, W. W.; McWilliams, R.; Zhao, L.; Carter, T.; Leneman, D.; Vincena, S.

2004-11-01

Understanding the spatial transport induced by fluctuations is important to the confinement of magnetized plasmas. The paradox of fast ions being much better confined than thermal ions, i.e. the effective diffusion coefficient of fast ions being much smaller than that of thermal ions, has been observed experimentally [1], explained theoretically [2], and analyzed by simulations [3]. Gyroradius averaging and drift averaging are two predicted effects that are responsible for reduced fast-ion transport. Our goal is to quantitatively confirm these effects and make further exploration by measuring fast-ion transport as a function of gyroradius in the LArge Plasma Device (LAPD) plasma with well-characterized background fluctuations. A 3D gridded analyzer is used to measure the spatial profile of the beam produced by an ion gun launching 500 eV Argon ions [4]. Strong drift wave fluctuations are generated by inserting a disk into the center of the plasma. First results will be presented. [1] W. Heidbrink, G. Sadler, Nucl. Fusion, Vol. 34, p. 535 (1994); [2] P. C. Efthimion et al., Plasma Phys. and Cont. Nucl. Fusion Res., Vol. 1, p. 307 (1988); [3] G. Manfredi, R. Dendy, Phys. Rev. Lett. 76, p. 4360 (1996); [4] H. Boehmer et al. , Rev. Sci. Instrum. , Vol. 75, p. 1013 (2002)

Educational Reform Hyperwaves: Reconceptualizing Cuban's Theories of Change

ERIC Educational Resources Information Center

Berkovich, Izhak

2017-01-01

The present work builds on Cuban's ("Educ Res" 19(1):3-13, 1990) seminal work on reform waves. The research explores reform waves in Israeli educational policies since 2000s. The historical case study analysis focuses on conservative and liberal-progressive reforms in education, and reveals that these reforms took place as reoccurring…

Speech and Debate as Civic Education

ERIC Educational Resources Information Center

Hogan, J. Michael; Kurr, Jeffrey A.; Johnson, Jeremy D.; Bergmaier, Michael J.

2016-01-01

In light of the U.S. Senate's designation of March 15, 2016 as "National Speech and Debate Education Day" (S. Res. 398, 2016), it only seems fitting that "Communication Education" devote a special section to the role of speech and debate in civic education. Speech and debate have been at the heart of the communication…

High spatial resolution detection of low-energy electrons using an event-counting method, application to point projection microscopy

NASA Astrophysics Data System (ADS)

Salançon, Evelyne; Degiovanni, Alain; Lapena, Laurent; Morin, Roger

2018-04-01

An event-counting method using a two-microchannel plate stack in a low-energy electron point projection microscope is implemented. 15 μm detector spatial resolution, i.e., the distance between first-neighbor microchannels, is demonstrated. This leads to a 7 times better microscope resolution. Compared to previous work with neutrons [Tremsin et al., Nucl. Instrum. Methods Phys. Res., Sect. A 592, 374 (2008)], the large number of detection events achieved with electrons shows that the local response of the detector is mainly governed by the angle between the hexagonal structures of the two microchannel plates. Using this method in point projection microscopy offers the prospect of working with a greater source-object distance (350 nm instead of 50 nm), advancing toward atomic resolution.

Thermodynamics of adaptive molecular resolution

NASA Astrophysics Data System (ADS)

Delgado-Buscalioni, R.

2016-11-01

A relatively general thermodynamic formalism for adaptive molecular resolution (AMR) is presented. The description is based on the approximation of local thermodynamic equilibrium and considers the alchemic parameter λ as the conjugate variable of the potential energy difference between the atomistic and coarse-grained model Φ=U(1)-U(0). The thermodynamic formalism recovers the relations obtained from statistical mechanics of H-AdResS (Español et al., J. Chem. Phys. 142, 064115, 2015 (doi:10.1063/1.4907006)) and provides relations between the free energy compensation and thermodynamic potentials. Inspired by this thermodynamic analogy, several generalizations of AMR are proposed, such as the exploration of new Maxwell relations and how to treat λ and Φ as `real' thermodynamic variables. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

Mirror Instability: Quasi-linear Effects

NASA Astrophysics Data System (ADS)

Hellinger, P.; Travnicek, P. M.; Passot, T.; Sulem, P.; Kuznetsov, E. A.

2008-12-01

Nonlinear properties of the mirror instability are investigated by direct integration of the quasi-linear diffusion equation [Shapiro and Shevchenko, 1964] near threshold. The simulation results are compared to the results of standard hybrid simulations [Califano et al., 2008] and discussed in the context of the nonlinear dynamical model by Kuznetsov et al. [2007]. References: Califano, F., P. Hellinger, E. Kuznetsov, T. Passot, P. L. Sulem, and P. M. Travnicek (2008), Nonlinear mirror mode dynamics: Simulations and modeling, J. Geophys. Res., 113, A08219, doi:10.1029/2007JA012898. Kuznetsov, E., T. Passot and P. L. Sulem (2007), Dynamical model for nonlinear mirror modes near threshold, Phys. Rev. Lett., 98, 235003 . Shapiro, V. D., and V. I. Shevchenko (1964), Quasilinear theory of instability of a plasma with an anisotropic ion velocity distribution, Sov. JETP, 18, 1109.

Trend of surface solar radiation over Asia simulated by aerosol transport-climate model

NASA Astrophysics Data System (ADS)

Takemura, T.; Ohmura, A.

2009-12-01

Long-term records of surface radiation measurements indicate a decrease in the solar radiation between the 1950s and 1980s (“global dimming”), then its recovery afterward (“global brightening”) at many locations all over the globe [Wild, 2009]. On the other hand, the global brightening is delayed over the Asian region [Ohmura, 2009]. It is suggested that these trends of the global dimming and brightening are strongly related with a change in aerosol loading in the atmosphere which affect the climate change through the direct, semi-direct, and indirect effects. In this study, causes of the trend of the surface solar radiation over Asia during last several decades are analyzed with an aerosol transport-climate model, SPRINTARS. SPRINTARS is coupled with MIROC which is a general circulation model (GCM) developed by Center for Climate System Research (CCSR)/University of Tokyo, National Institute for Environmental Studies (NIES), and Frontier Research Center for Global Change (FRCGC) [Takemura et al., 2000, 2002, 2005, 2009]. The horizontal and vertical resolutions are T106 (approximately 1.1° by 1.1°) and 56 layers, respectively. SPRINTARS includes the transport, radiation, cloud, and precipitation processes of all main tropospheric aerosols (black and organic carbons, sulfate, soil dust, and sea salt). The model treats not only the aerosol mass mixing ratios but also the cloud droplet and ice crystal number concentrations as prognostic variables, and the nucleation processes of cloud droplets and ice crystals depend on the number concentrations of each aerosol species. Changes in the cloud droplet and ice crystal number concentrations affect the cloud radiation and precipitation processes in the model. Historical emissions, that is consumption of fossil fuel and biofuel, biomass burning, aircraft emissions, and volcanic eruptions are prescribed from database provided by the Aerosol Model Intercomparison Project (AeroCom) and the latest IPCC inventories. Continuous hindcast simulation during the last several decades is done to compare with surface radiation measurements. Cause of the global dimming and brightening is separated into the aerosol direct and indirect effects from the simulation. Acknowledgments. The simulation in this study was performed on the NIES supercomputer system (NEC SX-8R). This study is partly supported by the Global Environment Research Fund (RF-091) by the Ministry of the Environment of Japan, Grant-in-Aid for Young Scientist (21681001) by the Ministry of Education, Culture, Sports, Science, and Technology of Japan, and Mitsui & Co., Ltd. Environment Fund (R08-D035). References Ohmura, A. (2009), J. Geophys. Res., 114, doi:10.1029/2008JD011290. Takemura, T., et al. (2000), J. Geophys. Res., 105, 17853-17873. Takemura, T., et al. (2002), J. Climate, 15, 333-352. Takemura, T., et al. (2005), J. Geophys. Res., 110, doi:10.1029/2004JD005029. Takemura, T., et al. (2009), Atmos. Chem. Phys., 9, 3061-3073. Wild, M. (2009), J. Geophys. Res., 114, doi:10.1029/2008JD011470.

Radio-Frequency Emissions from Streamer Collisions: Implications for High-Energy Processes.

NASA Astrophysics Data System (ADS)

Luque, A.

2017-12-01

The production of energetic particles in a discharge corona is possibly linked to the collision of streamers of opposite polarities [Cooray et al. (2009), Kochkin et al. (2012), Østgaard et al. (2016)]. There is also experimental evidence linking it to radio-frequency emissions in the UHF frequency range (300 MHz-3 GHz) [Montanyà et al. (2015), Petersen and Beasley (2014)]. Here we investigate these two links by modeling the radio-frequency emissions emanating from an encounter between two counter-propagating streamers. Our numerical model combines self-consistently a conservative, high-order Finite-Volume scheme for electron transport with a Finite-Difference Time-Domain (FDTD) method for electromagnetic propagation. We also include the most relevant reactions for streamer propagation: impact ionization, dissociative attachment and photo-ionization. Our implementation benefits from massive parallelization by running on a General-Purpose Graphical Processing Unit (GPGPU). With this code we found that streamer encounters emit electromagnetic waves predominantly in the UHF range, supporting the hypothesis that streamer collisions are essential precursors of high-energy processes in electric discharges. References Cooray, V., et al., J. Atm. Sol.-Terr. Phys., 71, 1890, doi:10.1016/j.jastp.2009.07.010 (2009). Kochkin, P. O., et al., J. Phys. D, 45, 425202, doi: 10.1088/0022-3727/45/42/425202 (2012). Montanyà, J., et al., J. Atm. Sol.-Terr. Phys., 136, 94, doi:10.1016/j.jastp.2015.06.009, (2015). Østgaard, N., et al., J. Geophys. Res. (Atmos.), 121, 2939, doi:10.1002/2015JD024394 (2016). Petersen, D., and W. Beasley, Atmospheric Research, 135, 314, doi:10.1016/j.atmosres.2013.02.006 (2014).

The defective nature of ice Ic and its implications for atmospheric science

NASA Astrophysics Data System (ADS)

Kuhs, W. F.; Hansen, T. C.

2009-04-01

The possible atmospheric implication of ice Ic (cubic ice) has already been suggested some time ago in the context of snow crystal formation [1]. New findings from air-borne measurements in cirrus clouds and contrails have put ice Ic into the focus of interest to understand the so-called "supersaturation puzzle" [2,3,4,5]. Our recent microstructural work on ice Ic [6,7] appears to be highly relevant in this context. We have found that ice Ic is characterized by a complex stacking fault pattern, which changes as a function of temperature as well as time. Indeed, from our own [8] and other group's work [9] one knows that (in contrast to earlier believe) ice Ic can form up to temperatures at least as high as 240K - thus in the relevant range for cirrus clouds. We have good preliminary evidence that the "cubicity" (which can be related to stacking fault probabilities) as well as the particle size of ice Ic are the relevant parameters for this correlation. The "cubicity" of stacking faulty ice Ic (established by diffraction) correlates nicely with the increased supersaturation at decreasing temperatures observed in cirrus clouds and contrails, a fact, which may be considered as further evidence for the presence of ice Ic. Moreover, the stacking faults lead to kinks in the outer shapes of the minute ice Ic crystals as seen by cryo scanning electron microscopy (cryo-SEM); these defective sites are likely to play some role in heterogeneous reactions in the atmosphere. The cryo-SEM work suggests that stacking-faulty ice Ic has many more active centres for such reactions than the usually considered thermodynamically stable form, ice Ih. [1] T Kobayashi & T Kuroda (1987) Snow Crystals. In: Morphology of Crystals (ed. I Sunagawa), Terra Scientific Publishing, Tokyo, pp.649-743. [2] DM Murphy (2003) Dehydration in cold clouds is enhanced by a transition from from cubic to hexagonal ice. Geophys.Res.Lett.,30, 2230, doi:10.1029/2003GL018566. [3] RS Gao & 19 other authors (2004) Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds. Science 303, 516-520. [4] T Peter, C Marcolli, P Spaichinger, T Corti, MC Baker & T Koop (2006) When dry air is too humid. Science 314, 1399-1402. [5] JE Shilling, MA Tolbert, OB Toon, EJ Jensen, BJ Murray & AK Bertram (2006) Measurements of the vapor pressure of cubic ice and their implications for atmospheric ice clouds. Geophys.Res.Lett. 33, 026671. [6] TC Hansen, MM Koza & WF Kuhs (2008) Formation and annealing of cubic ice: I Modelling of stacking faults. J.Phys.Cond.Matt. 20, 285104. [7] TC Hansen, MM Koza, P Lindner & WF Kuhs (2008) Formation and annealing of cubic ice: II. Kinetic study. J.Phys.Cond.Matt. 20, 285105. [8] WF Kuhs, G Genov, DK Staykova & AN Salamatin (2004) Ice perfection and the onset of anomalous preservation of gas hydrates. Phys.Chem.Chem.Phys. 6, 4917-4920. [9] BJ Murray, DA Knopf & AK Bertram (2005) The formation of cubic ice under conditions relevant to Earth's atmosphere. Nature 434, 292-205.

Role of resilience and social support in alleviating depression in patients receiving maintenance hemodialysis.

PubMed

Liu, Yueh-Min; Chang, Hong-Jer; Wang, Ru-Hwa; Yang, Li-King; Lu, Kuo-Cheng; Hou, Yi-Chou

2018-01-01

Patients who undergo hemodialysis encounter challenges including role changes, physical degeneration, and difficulty in performing activities of daily living (ADLs) and self-care. These challenges deteriorate their physiological and psychosocial conditions, resulting in depression. High resilience (RES) and social support can alleviate stress and depression. This study evaluated the importance of RES and social support in managing depression in elderly patients undergoing maintenance hemodialysis (HD). In this descriptive, correlational study, 194 older patients undergoing HD were enrolled from the HD centers of three hospitals in northern Taiwan. The Barthel ADL Index, RES scale, Inventory of Socially Supportive Behavior, and Beck Depression Inventory-II were used. Hierarchical regression analysis was applied to evaluate the interaction of RES and social support with illness severity, demographics, and ADLs. Of the total participants, 45.9% experienced depressive symptoms. Demographic analysis showed that men and those with high educational level and income and financial independence had less depression ( p <0.01). Patients with a higher Barthel Index (n=103), RES scale (n=33), and social support (n=113) showed less depressive symptoms ( p <0.01). We found a significant negative correlation between depressive symptoms and social support ( r =-0.506, p <0.01) and RES ( r =-0.743, p <0.01). Hierarchical regression analysis showed that RES could buffer the effects of symptom severity on depression ( b =-0.436, p <0.01), but social support did not exert a buffering effect. The severity of illness symptoms and ADLs were the major determinants of depressive symptoms. High RES could alleviate depressive symptoms in the older patients undergoing HD.

Computerized Vocational Guidance (CVG) Systems: Evaluation for Use in Military Recruiting.

DTIC Science & Technology

1984-02-01

how to relate the two, and how to explore, project, and choose. Whether Rogerian or more directive in nature, the essential counseling ingredient is to...Conference, Princeton, NJ: Educational Testing Service, 1974, 43-69. Katz, M. R., & Shatkin, L. Computer-assisted guidance: Concepts and practices (Res. Rep...Canadian Forces Personnel Applied Research Unit, 1980. Katz, M. R., & Shatkin, L. Computer-assisted guidance: Concepts and practices (Res. Rep. RR-80-1

How to improve the collection and analysis of hospital antibiotic consumption: preliminary results of the ConsoRes software experimental implementation.

PubMed

Boussat, S; Demoré, B; Lozniewski, A; Aissa, N; Rabaud, C

2012-04-01

The online software ConsoRes is used to collect and analyze data on antibiotic consumption and evolution of bacterial resistance in healthcare institutions in every hospital ward (HW). We report the first results of ConsoRes implementation in the northeast hospitals of France. ConsoRes was implemented in January 2011, in nine volunteer hospitals after performing an onsite assessment. Five of these hospitals were already monitoring antibiotic consumption with a network such as Raisin ATB or Antibiolor, providing feedback on the various evaluation tools. The ConsoRes data collection import function meets expectations of pharmacists, bacteriologists, or clinicians since it is user friendly, prevents redundant data input, and allows data transfer to the national databases. Importing the hospital organizational structure prevents mistakes on consumption allocation, which was noted in the previous databases, and makes comparison and benchmark analysis reliable. ConsoRes also provides a rapid consumption data feedback to all registered users within the hospital, whether in charge of a ward (clinician) or having a transversal function (pharmacist, bacteriologist). The availability of an automatic standard report or of an online customized report is another major feature of ConsoRes. Besides providing surveillance, the concomitant analysis of local antibiotic consumption and bacterial resistance should have an educational impact by allowing each user to implement actions within the framework of antibiotic stewardship. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Sustaining Physics Teacher Education Coalition Programs in Physics Teacher Education

ERIC Educational Resources Information Center

Scherr, Rachel E.; Plisch, Monica; Goertzen, Renee Michelle

2017-01-01

Understanding the mechanisms of increasing the number of physics teachers educated per year at institutions with thriving physics teacher preparation programs may inspire and support other institutions in building thriving programs of their own. The Physics Teacher Education Coalition (PhysTEC), led by the American Physical Society (APS) and the…

Cinema, Fermi problems and general education

NASA Astrophysics Data System (ADS)

Efthimiou, C. J.; Llewellyn, R. A.

2007-05-01

During the past few years the authors have developed a new approach to the teaching of physical science, a general education course typically found in the curricula of nearly every college and university. This approach, called Physics in Films (Efthimiou and Llewellyn 2006 Phys. Teach. 44 28-33), uses scenes from popular films to illustrate physical principles and has excited student interest and improved student performance. A similar approach at the senior/high-school level, nicknamed Hollywood Physics, has been developed by Chandler (2006 Phys. Teach. 44 290-2 2002 Phys. Teach. 40 420-4). The two approaches may be considered complementary as they target different student groups. The analyses of many of the scenes in Physics in Films are a direct application of Fermi calculations—estimates and approximations designed to make solutions of complex and seemingly intractable problems understandable to the student non-specialist. The intent of this paper is to provide instructors with examples they can use to develop skill in recognizing Fermi problems and making Fermi calculations in their own courses.

Characterization of Acremonium and Isaria ice nuclei

NASA Astrophysics Data System (ADS)

Pummer, Bernhard G.; Pöschl, Ulrich; Fröhlich-Nowoisky, Janine

2014-05-01

Until recently, the only known fungal ice nuclei (IN) were a few exponents of lichen mycobionts and Fusarium spp. [Kieft and Ruscetti 1990, Pouleur et al. 1992, Hasegawa et al. 1994, Tsumuki et al. 1995], as well as two strains of mold [Jayaweera and Flanagan 1982]. Other investigated species did not show any IN activity [Pouleur et al. 1992, Iannone et al. 2011, Pummer et al. 2013]. In the last few years, IN-activity has been discovered in some rust and smut fungi [Morris et al. 2013, Haga et al. 2013], Acremonium implicatum (Acr.) and Isaria farinosa (Isa.) [Huffman et al. 2013] and a handful of other airborne and soil fungi [unpublished data]. We started characterizing the IN of Acr. and Isa.: Like other non-bacterial biological IN, they can be easily separated from the cells in aqueous suspension, and keep their activity. The IN-active aqueous suspensions were processed by filtration (5 μm, 0.1 μm, 300 kDa, 100 kDa) and exposure to heat (60° C) or guanidinium chloride (6 M). The IN activity of the processed samples was measured by a freezing assay of droplets, as described by Pummer et al. [2013]. Via the Vali formula, we calculated the amount of IN per gram of mycelium, which is higher than 105 g-1. The initial freezing temperature was -4° C for Isaria and -8° C for Acremonium IN. Both were completely knocked out by 60° C or guanidinium chloride. The Acremonium IN are in a mass range between 100 and 300 kDa. The Isaria IN seem to be either a bit larger, or more attached to larger particles, since not all of them pass through the 300-kDa-filter. It is likely that both of these new IN are proteinaceous like the IN of Fusarium spp. and lichen mycobionts, which belong to the Ascomycota phylum. Since the Isaria IN show a high onset freezing temperature and are rather large for single molecules, they might be agglomerates. Haga D.I. et al. (2013) J. Geophys. Res.: Atm. 118, 7260-7272 Hasegawa Y. et al. (1994) Biosci. Biotech. Biochem. 58, 2273-2274 Huffman A.J. et al. (2013) Atmos. Chem. Phys. 13, 6151-6164 Iannone R. et al. (2011) Atmos. Chem. Phys. 11, 1191-1201 Jayaweera K. and Flanagan P. (1982) Geophys. Res. Lett. 9, 94-97 Kieft T.L. and Ruscetti T. (1990) J. Bacteriol. 172, 3519-3523 Morris C.E. et al. (2013) Atmos. Chem. Phys. 13, 4223-4233 Pouleur S. et al. (1992) Appl. Environ. Microbiol. 58, 2960-2964 Pummer B. et al. (2013) Biogeosci. 10, 8083-8091 Tsumuki H. et al. (1995) Ann. Phytopathol. Soc. Jpn. 61, 334-339

Droplet Growth Kinetics in Various Environments

NASA Astrophysics Data System (ADS)

Raatikainen, T. E.; Lathem, T. L.; Moore, R.; Lin, J. J.; Cerully, K. M.; Padro, L.; Lance, S.; Cozic, J.; Anderson, B. E.; Nenes, A.

2012-12-01

The largest uncertainties in the effects of atmospherics aerosols on the global radiation budget are related to their indirect effects on cloud properties (IPCC, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007). Cloud formation is a kinetic process where the resulting cloud properties depend on aerosol properties and meteorological parameters such as updraft velocity (e.g. McFiggans et al., Atmos. Chem. Phys., 6, 2593-2649, 2006). Droplet growth rates are limited by the water vapor diffusion, but additional kinetic limitations, e.g., due to organic surface films, slow solute dissociation or highly viscous or glassy aerosol states have been hypothesized. Significant additional kinetic limitations can lead to increased cloud droplet number concentration, thus the effect is similar to those of increased aerosol number concentration or changes in vertical velocity (e.g. Nenes et al., Geophys. Res. Lett., 29, 1848, 2002). There are a few studies where slow droplet growth has been observed (e.g. Ruehl et al., Geophys. Res. Lett., 36, L15814, 2009), however, little is currently known about their global occurrence and magnitude. Cloud micro-physics models often describe kinetic limitations by an effective water vapor uptake coefficient or similar parameter. Typically, determining aerosol water vapor uptake coefficients requires experimental observations of droplet growth which are interpreted by a numerical droplet growth model where the uptake coefficient is an adjustable parameter (e.g. Kolb et al., Atmos. Chem. Phys., 10, 10561-10605, 2010). Such methods have not been practical for high time-resolution or long term field measurements, until a model was recently developed for analyzing Droplet Measurement Technologies (DMT) cloud condensation nuclei (CCN) counter data (Raatikainen et al., Atmos. Chem. Phys., 12, 4227-4243, 2012). Model verification experiments showed that the calibration aerosol droplet size can be predicted accurately for various instrument settings and also in the case of high CCN concentrations when water vapor depletion decreases supersaturation and droplet size (Lathem and Nenes, Aerosol Sci. Tech., 45, 604-615, 2011). The model also accounts for aerosol hygroscopicity and size distribution variations, which can have significant effects on the droplet size. We have examined cloud droplet activation and growth kinetics by analyzing several DMT CCN counter data sets collected from various environments including boreal forests, arctic areas, fresh and aged biomass burning plumes, and polluted and biogenically influenced urban areas (Raatikainen et al., In preparation, 2012). Model simulations show that the variations in observed droplet size are caused by water vapor depletion effects, changes in dry particle size distributions and hygroscopicity, and changes in instrument supersaturation profiles. This means that fast droplet growth kinetics with water uptake coefficient close to 0.2 is prevalent at least for the studied environments.

Role of resilience and social support in alleviating depression in patients receiving maintenance hemodialysis

PubMed Central

Liu, Yueh-Min; Chang, Hong-Jer; Wang, Ru-Hwa; Yang, Li-King; Lu, Kuo-Cheng; Hou, Yi-Chou

2018-01-01

Background Patients who undergo hemodialysis encounter challenges including role changes, physical degeneration, and difficulty in performing activities of daily living (ADLs) and self-care. These challenges deteriorate their physiological and psychosocial conditions, resulting in depression. High resilience (RES) and social support can alleviate stress and depression. This study evaluated the importance of RES and social support in managing depression in elderly patients undergoing maintenance hemodialysis (HD). Patients and methods In this descriptive, correlational study, 194 older patients undergoing HD were enrolled from the HD centers of three hospitals in northern Taiwan. The Barthel ADL Index, RES scale, Inventory of Socially Supportive Behavior, and Beck Depression Inventory-II were used. Hierarchical regression analysis was applied to evaluate the interaction of RES and social support with illness severity, demographics, and ADLs. Results Of the total participants, 45.9% experienced depressive symptoms. Demographic analysis showed that men and those with high educational level and income and financial independence had less depression (p<0.01). Patients with a higher Barthel Index (n=103), RES scale (n=33), and social support (n=113) showed less depressive symptoms (p<0.01). We found a significant negative correlation between depressive symptoms and social support (r=−0.506, p<0.01) and RES (r=−0.743, p<0.01). Hierarchical regression analysis showed that RES could buffer the effects of symptom severity on depression (b=−0.436, p<0.01), but social support did not exert a buffering effect. Conclusion The severity of illness symptoms and ADLs were the major determinants of depressive symptoms. High RES could alleviate depressive symptoms in the older patients undergoing HD. PMID:29535526

Thermodynamics of adaptive molecular resolution.

PubMed

Delgado-Buscalioni, R

2016-11-13

A relatively general thermodynamic formalism for adaptive molecular resolution (AMR) is presented. The description is based on the approximation of local thermodynamic equilibrium and considers the alchemic parameter λ as the conjugate variable of the potential energy difference between the atomistic and coarse-grained model Φ=U (1) -U (0) The thermodynamic formalism recovers the relations obtained from statistical mechanics of H-AdResS (Español et al, J. Chem. Phys. 142, 064115, 2015 (doi:10.1063/1.4907006)) and provides relations between the free energy compensation and thermodynamic potentials. Inspired by this thermodynamic analogy, several generalizations of AMR are proposed, such as the exploration of new Maxwell relations and how to treat λ and Φ as 'real' thermodynamic variablesThis article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).

Corrigendum to "Crater functions for compound materials: A route to parameter estimation in coupled-PDE models of ion bombardment" [Nucl. Instr. Meth. Phys. Res. B 318B (2014) 245-252

NASA Astrophysics Data System (ADS)

Norris, Scott A.; Samela, Juha; Vestberg, Matias; Nordlund, Kai; Aziz, Michael J.

2015-04-01

Because Eq. (1) is independent of the details of the crater function Δh , updated formulae for { A, C,A‧,C‧ } that account for the curvature dependence are obtained simply by inserting Harrison and Bradley's expressions (2) into Eq. (1). As those authors show, at normal incidence the added terms are expected to have positive values, increasing estimates of C (which is a sum of SX,YZ, type terms), while producing a less noticable effect on the value of C‧ (which is a difference of SX,YZ, type terms). These modifications therefore do not alter the primary physical conclusions of our study, which are that for the GaSb system both C and (A‧ C -C‧ A) appear to be positive.

High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fletcher, L. B., E-mail: lbfletch@slac.stanford.edu; Galtier, E.; Gamboa, E. J.

2016-11-15

We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focusedmore » on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less

Numerical Simulations of Strong MHD Turbulence

NASA Astrophysics Data System (ADS)

Mason, J.; Cattaneo, F.; Boldyrev, S.

2007-11-01

Magnetohydrodynamic turbulence plays an important role in many astrophysical phenomena, including the solar wind, angular momentum transport in accretion disks and interstellar scintillation. Despite more than 40 years of investigations much within the subject remains controversial. Recently a new theory has been developed [1, 2]. It predicts a scale-dependent dynamic alignment between the velocity and magnetic fluctuations and leads to the field-perpendicular energy spectrum E(k)k-3/2. Here we discuss this new theory and present the results of a series of numerical tests. Quantities measured include the alignment angle, the spectrum and the third order structure functions for which the exact relations due to Politano & Pouquet [3] hold. [1] Boldyrev, S. (2005) Astrophys. J. 626, L37. [2] Boldyrev, S. (2006) Phys. Rev. Lett. 96, 115002. [3] Politano, H. & Pouquet, A. (1998) Geophys. Res. Lett. 25, 273.

Matter density versus distance for the neutrino beam from Fermilab to Lead, South Dakota, and comparison of oscillations with variable and constant density

NASA Astrophysics Data System (ADS)

Roe, Byron

2017-06-01

This paper is divided into two parts. In the first part, the material densities passed through for neutrinos going from FNAL to Sanford Laboratory are calculated using two recent density tables, Crustal [G. Laske, G. Masters, Z. Ma, and M. Pasyanos, Update on CRUST1.0—A 1-degree global model of Earth's crust, Geophys. Res. Abstracts 15, EGU2013-2658 (2013),; For the programs and tables, see the website: http://igppweb.ucsd.edu/ gabi/crust1.html.] and Shen-Ritzwoller [W. Shen and M. H. Ritzwoller, Crustal and uppermost mantle structure beneath the United States, J. Geophys. Res.: Solid Earth 121, 4306 (2016)], as well as the values from an older table PEMC [A. M. Dziewonski, A. L. Hales, and E. R. Lapwood, Parametrically simple earth models consistent with geophysical data, Phys. Earth Plan. Int. 10, 12 (1975); For further information see the website: http://ds.iris.edu/ds/products/emc-pem/.]. In the second part, neutrino oscillations at Sanford Laboratory are examined for the variable density table of Shen-Ritzwoller. These results are then compared with oscillation results using the mean density from the Shen-Ritzwoller tables and with one other fixed density. For the tests made here, the mean density results are quite similar to the results using the variable density vs distance.

Detection of Heater Generated Super Small Scale Striations Using GPS Signal Diagnostics

NASA Astrophysics Data System (ADS)

Najmi, A. C.; Milikh, G. M.; Chiang, K.; Psiaki, M.; Secan, J. A.; Bernhardt, P. A.; Briczinski, S. J.; Siefring, C. L.; Papadopoulos, K.

2013-12-01

Recent theoretical models predict that super small striations (SSS) of the electron density, on the order of ten centimeters, can be excited by HF waves with frequency close to multiples of the electron gyro frequency [Gurevich et al., 2006]. The first experimental verification of SSS was made at HAARP [Milikh et al., 2008]. We present results of HAARP experiments that include simultaneous observations of GPS carrier phase and SEE observations of ionospheric turbulence. These observations show that SSS excited by HF frequencies near the fourth harmonic of the gyro frequency scatter GPS signals, and in three out of six experiments indicate the presence of strong turbulence, similar to that observed in descending artificial ionized layer experiments [Pedersen et al., 2010]. This turbulence is capable of generating suprathermal electrons, and in one of the experiments, the presence of fast electrons was confirmed by the HAARP incoherent scattering radar. Estimates on the SSS shows that they correspond to 3-10% electron density depletions. Such irregularities affect UHF signals including GPS, and thus can be important in applications. Gurevich, A.V. and K.P. Zybin (2006), Phys. Lett. A, 358, 159. Milikh, G., et al. (2008), Geophys. Res. Let., 35, L22102, doi:10.1029/2008GL035527. Pedersen, T. et al. (2010), Geophys. Res. Let., 37, L02106, doi:10.1029/2009GL041895.

Shock vaporization of carbonate and sulfate minerals

NASA Astrophysics Data System (ADS)

Shen, A. H.; Ahrens, T. J.; O'Keefe, J. D.

2001-12-01

Strong shock waves induced by impacts can cause vaporization of rocks and minerals. The products of such process play important roles in planetary differentiation (Yakovlev et al., Geochem. International, 38, 1027, 2000) and in effecting the planetary climate. Many experiments and computer simulations have been performed to simulate the Chicxulub impact at Cretaceous/Tertiary boundary (see, for example, Pierazzo et al., J. Geophys. Res., 103, 28607, 1998 and Pope et al., J. Geophys. Res., 102, 21645, 1997). However, the pressure range for incipient and complete vaporization of carbonates and sulfates are not well constrained, especially, for minerals with various initial porosities. Furthermore, evidence for chemical species in the products of vaporized carbonate and sulfate minerals is almost non-existing. In this study, we employed published Hugoniot data for carbonate and sulfate minerals. By using the methods described in Ahrens (J. Appl. Phys., 43, 2443, 1972) and Ahrens and O'Keefe (The Moon, 4, 214, 1972), we calculated the entropy associated with the thermodynamic states produced by hypervelocity impacts at various velocities for carbonate and sulfate minerals with different initial porosities. The results were compared with the entropy of incipient vaporization and complete vaporization of these minerals to determine the degree of vaporization due to impacts. Moreover, these results are utilized to guide our experimental study in speciation reactions in shock-induced vaporization of carbonates and sulfates.

Building on "Red Dirt" Perspectives: What Counts as Important for Remote Education?

ERIC Educational Resources Information Center

Guenther, John; Disbray, Samantha; Osborne, Sam

2015-01-01

The Remote Education Systems (RES) project within the Cooperative Research Centre for Remote Economic Participation (CRC-REP) has, over the last four years, gathered and analysed qualitative data directly from over 230 remote education stakeholders and from more than 700 others through surveys. The research was designed to answer four questions:…

Concurrent Enrollment: Comparing How Educators and Students Categorize Students' Motivations

ERIC Educational Resources Information Center

Dare, Alec; Dare, Lynn; Nowicki, Elizabeth

2017-01-01

High-ability students have special education needs that are often overlooked or misunderstood (Blaas in "Aust J Guid Couns" 24(2):243-255, 2014) which may result in talent loss (Saha and Sikora in "Int J Contemp Sociol Discuss J Contemp Ideas Res" 48(1):9-34, 2011). Educational acceleration can help avoid these circumstances…

Continuum Vlasov Simulation in Four Phase-space Dimensions

NASA Astrophysics Data System (ADS)

Cohen, B. I.; Banks, J. W.; Berger, R. L.; Hittinger, J. A.; Brunner, S.

2010-11-01

In the VALHALLA project, we are developing scalable algorithms for the continuum solution of the Vlasov-Maxwell equations in two spatial and two velocity dimensions. We use fourth-order temporal and spatial discretizations of the conservative form of the equations and a finite-volume representation to enable adaptive mesh refinement and nonlinear oscillation control [1]. The code has been implemented with and without adaptive mesh refinement, and with electromagnetic and electrostatic field solvers. A goal is to study the efficacy of continuum Vlasov simulations in four phase-space dimensions for laser-plasma interactions. We have verified the code in examples such as the two-stream instability, the weak beam-plasma instability, Landau damping, electron plasma waves with electron trapping and nonlinear frequency shifts [2]^ extended from 1D to 2D propagation, and light wave propagation.^ We will report progress on code development, computational methods, and physics applications. This work was performed under the auspices of the U.S. DOE by LLNL under contract no. DE-AC52-07NA27344. This work was funded by the Lab. Dir. Res. and Dev. Prog. at LLNL under project tracking code 08-ERD-031. [1] J.W. Banks and J.A.F. Hittinger, to appear in IEEE Trans. Plas. Sci. (Sept., 2010). [2] G.J. Morales and T.M. O'Neil, Phys. Rev. Lett. 28,417 (1972); R. L. Dewar, Phys. Fluids 15,712 (1972).

Experimental derivation of the fluence non-uniformity correction for air kerma near brachytherapy linear sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vianello, E. A.; Almeida, C. E. de

2008-07-15

In brachytherapy, one of the elements to take into account for measurements free in air is the non-uniformity of the photon fluence due to the beam divergence that causes a steep dose gradient near the source. The correction factors for this phenomenon have been usually evaluated by two available theories by Kondo and Randolph [Radiat. Res. 13, 37-60 (1960)] and Bielajew [Phys. Med. Biol. 35, 517-538 (1990)], both conceived for point sources. This work presents the experimental validation of the Monte Carlo calculations made by Rodriguez and deAlmeida [Phys. Med. Biol. 49, 1705-1709 (2004)] for the non-uniformity correction specifically formore » a Cs-137 linear source measured using a Farmer type ionization chamber. The experimental values agree very well with the Monte Carlo calculations and differ from the results predicted by both theoretical models widely used. This result confirms that for linear sources there are some important differences at short distances from the source and emphasizes that those theories should not be used for linear sources. The data provided in this study confirm the limitations of the mentioned theories when linear sources are used. Considering the difficulties and uncertainties associated with the experimental measurements, it is recommended to use the Monte Carlo data to assess the non-uniformity factors for linear sources in situations that require this knowledge.« less

Improved Critical Eigenfunction Restriction Estimates on Riemannian Surfaces with Nonpositive Curvature

NASA Astrophysics Data System (ADS)

Xi, Yakun; Zhang, Cheng

2017-03-01

We show that one can obtain improved L 4 geodesic restriction estimates for eigenfunctions on compact Riemannian surfaces with nonpositive curvature. We achieve this by adapting Sogge's strategy in (Improved critical eigenfunction estimates on manifolds of nonpositive curvature, Preprint). We first combine the improved L 2 restriction estimate of Blair and Sogge (Concerning Toponogov's Theorem and logarithmic improvement of estimates of eigenfunctions, Preprint) and the classical improved {L^∞} estimate of Bérard to obtain an improved weak-type L 4 restriction estimate. We then upgrade this weak estimate to a strong one by using the improved Lorentz space estimate of Bak and Seeger (Math Res Lett 18(4):767-781, 2011). This estimate improves the L 4 restriction estimate of Burq et al. (Duke Math J 138:445-486, 2007) and Hu (Forum Math 6:1021-1052, 2009) by a power of {(log logλ)^{-1}}. Moreover, in the case of compact hyperbolic surfaces, we obtain further improvements in terms of {(logλ)^{-1}} by applying the ideas from (Chen and Sogge, Commun Math Phys 329(3):435-459, 2014) and (Blair and Sogge, Concerning Toponogov's Theorem and logarithmic improvement of estimates of eigenfunctions, Preprint). We are able to compute various constants that appeared in (Chen and Sogge, Commun Math Phys 329(3):435-459, 2014) explicitly, by proving detailed oscillatory integral estimates and lifting calculations to the universal cover H^2.

Asymmetric kinetic equilibria: Generalization of the BAS model for rotating magnetic profile and non-zero electric field

NASA Astrophysics Data System (ADS)

Dorville, Nicolas; Belmont, Gérard; Aunai, Nicolas; Dargent, Jérémy; Rezeau, Laurence

2015-09-01

Finding kinetic equilibria for non-collisional/collisionless tangential current layers is a key issue as well for their theoretical modeling as for our understanding of the processes that disturb them, such as tearing or Kelvin Helmholtz instabilities. The famous Harris equilibrium [E. Harris, Il Nuovo Cimento Ser. 10 23, 115-121 (1962)] assumes drifting Maxwellian distributions for ions and electrons, with constant temperatures and flow velocities; these assumptions lead to symmetric layers surrounded by vacuum. This strongly particular kind of layer is not suited for the general case: asymmetric boundaries between two media with different plasmas and different magnetic fields. The standard method for constructing more general kinetic equilibria consists in using Jeans theorem, which says that any function depending only on the Hamiltonian constants of motion is a solution to the steady Vlasov equation [P. J. Channell, Phys. Fluids (1958-1988) 19, 1541 (1976); M. Roth et al., Space Sci. Rev. 76, 251-317 (1996); and F. Mottez, Phys. Plasmas 10, 1541-1545 (2003)]. The inverse implication is however not true: when using the motion invariants as variables instead of the velocity components, the general stationary particle distributions keep on depending explicitly of the position, in addition to the implicit dependence introduced by these invariants. The standard approach therefore strongly restricts the class of solutions to the problem and probably does not select the most physically reasonable. The BAS (Belmont-Aunai-Smets) model [G. Belmont et al., Phys. Plasmas 19, 022108 (2012)] used for the first time the concept of particle accessibility to find new solutions: considering the case of a coplanar-antiparallel magnetic field configuration without electric field, asymmetric solutions could be found while the standard method can only lead to symmetric ones. These solutions were validated in a hybrid simulation [N. Aunai et al., Phys. Plasmas (1994-present) 20, 110702 (2013)], and more recently in a fully kinetic simulation as well [J. Dargent and N. Aunai, Phys. Plasmas (submitted)]. Nevertheless, in most asymmetric layers like the terrestrial magnetopause, one would indeed expect a magnetic field rotation from one direction to another without going through zero [J. Berchem and C. T. Russell, J. Geophys. Res. 87, 8139-8148 (1982)], and a non-zero normal electric field. In this paper, we propose the corresponding generalization: in the model presented, the profiles can be freely imposed for the magnetic field rotation (although restricted to a 180 rotation hitherto) and for the normal electric field. As it was done previously, the equilibrium is tested with a hybrid simulation.

Broadening the Horizons of Research on Discovery-Based Learning

ERIC Educational Resources Information Center

Clements, Douglas H.; Joswick, Candace

2018-01-01

In reviewing the six articles within this "Instructional Science" special issue, we are reminded of Schoenfeld's ("Educ Res" 45(2):105-111, 2016) review of American Educational Research Association president-authored papers for the centennial celebration of AERA. There, he succinctly unveiled the content focus of AERA research…

Reserve Educational Assistance Program (REAP), Chapter 1607 Title 10, U.S. Code

ERIC Educational Resources Information Center

US Department of Veterans Affairs, 2005

2005-01-01

The Reserve Education Assistance Program, or REAP (Chapter 1607 of title 10, U.S. Code), is a new benefit providing educational assistance to members of the reserve components--Selected Reserve (Sel Res) and Individual Ready Reserve (IRR)--who are called or ordered to active service in response to a war or national emergency, as declared by the…

On the melting temperature measurements of metals under shock compression by pyrometry

NASA Astrophysics Data System (ADS)

Dai, Chengda; Hu, Jianbo; Tan, Hua

2009-06-01

The high-pressure melting temperatures are of interest in validating equation of state and modeling constitutive equation. The determination of melting temperatures for metals at megabars by pyrometry experiments is principally associated with the one-dimensional models for heat flow through dissimilar media: Grover-Urtiew model (J. App. Phys. 1974, 45: 146-152) and Tan-Ahrens model (High Press. Res. 1990, 2: 159-182). In the present work, we analyzed the insufficiency of Grover-Urtiew model in determining melting temperatures from observed interface temperatures. Based on the Tan-Ahrens model, we extracted the upper and lower bound on melting temperature at interface pressure, and proposed that the median of the both bounds was a good approximation to the melting temperatures at interface pressure. Pyrometry experiments were performed on tantalum, and the high-pressure melting temperatures were evaluated by application of the proposed approximation. The obtained results were compared with available theoretical calculations.

Index of Refraction of Shock Loaded Soda-Lime Glass

NASA Astrophysics Data System (ADS)

Alexander, C. S.

2009-12-01

Soda-lime glass (SLG) is a potential low-cost VISAR window for use at moderate shock pressures (up to 2430 GPa) where the material remains transparent. In order for SLG to be practical as a VISAR window, the correction factor, which describes the frequency correction related to the strain dependence of the refractive index, and hence the index of refraction itself, must be characterized as a function of pressure. Characterization data are reported in this paper and compared to previous results. The present data show good agreement with those of Dandekar [J. Appl. Phys. 84, 6614 (1998)] and separate study results by Gibbons and Ahrens [J. Geophys. Res. 76, 5489 (1971)] up to 7 GPa. However, at stresses over 7 GPa, marked discrepancies are evident between the present data and that of Gibbons and Ahrens. Differences in test methods may explain these discrepancies.

INDEX OF REFRACTION OF SHOCK LOADED SODA-LIME GLASS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexander, C. S.

2009-12-28

Soda-lime glass (SLG) is a potential low-cost VISAR window for use at moderate shock pressures (up to 2430 GPa) where the material remains transparent. In order for SLG to be practical as a VISAR window, the correction factor, which describes the frequency correction related to the strain dependence of the refractive index, and hence the index of refraction itself, must be characterized as a function of pressure. Characterization data are reported in this paper and compared to previous results. The present data show good agreement with those of Dandekar [J. Appl. Phys. 84, 6614 (1998)] and separate study results bymore » Gibbons and Ahrens [J. Geophys. Res. 76, 5489 (1971)] up to 7 GPa. However, at stresses over 7 GPa, marked discrepancies are evident between the present data and that of Gibbons and Ahrens. Differences in test methods may explain these discrepancies.« less

Dynamical core-hole screening in the x-ray absorption spectra of hydrogenated carbon nanotubes and graphene

NASA Astrophysics Data System (ADS)

Wessely, O.; Katsnelson, M. I.; Nilsson, A.; Nikitin, A.; Ogasawara, H.; Odelius, M.; Sanyal, B.; Eriksson, O.

2007-10-01

We have calculated the electronic structure and the x-ray absorption (XA) spectrum of a hydrogenated single graphite plane, in order to simulate recent experimental results on hydrogenated single wall carbon nanotubes (SWCNT) as well as hydrogenated graphene. We find that the presence of H induces a substantial component of sp3 bonding and as a result the π and π* components to the electronic structure vanish. We have calculated a theoretical x-ray absorption spectrum using a multiband version of the Mahan-Nozières-De Dominicis theory. By making a fitting of the XA signal of C atoms that have H attached to them and C atoms without H in the vicinity we obtain a good representation of the experimental data and we can draw the conclusion that in the experiments [A. Nikitin , Phys. Rev. Lett. 95, 225507 (2005)] some 35-50 % H have been absorbed in the SWCNT.

Effects of Density Fluctuations on Weakly Nonlinear Alfven Waves: An IST Perspective

NASA Astrophysics Data System (ADS)

Hamilton, R.; Hadley, N.

2012-12-01

The effects of random density fluctuations on oblique, 1D, weakly nonlinear Alfven waves is examined through a numerical study of an analytical model developed by Ruderman [M.S. Ruderman, Phys. Plasmas, 9 (7), pp. 2940-2945, (2002).]. Consistent with Ruderman's application to the one-parameter dark soliton, the effects on both one-parameter bright and dark solitons, the two-parameter soliton as well as pairs of one-parameter solitons were similar to that of Ohmic dissipation found by Hamilton et al. [R. Hamilton, D. Peterson, and S. Libby, J. Geophys. Res 114, A03104,doi:10.1029/2008JA013582 (2009).] It was found in all cases where bright or two-parameter solitons are present initially, that the effects of density fluctuations results in the eventual damping of such compressive wave forms and the formation of a train of dark solitons, or magnetic depressions.

High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

DOE PAGES

Fletcher, L. B.; Zastrau, U.; Galtier, E.; ...

2016-08-15

Here, we present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen andmore » focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less

Extension of the momentum transfer model to time-dependent pipe turbulence.

PubMed

Calzetta, Esteban

2012-02-01

We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows [Phys. Rev. Lett. 96, 044502 (2006)] to the case of time- and/or space-dependent turbulent flows. The end result is an expression for the stress at the wall as the sum of a steady and a dynamic component. The steady part is obtained by using the instantaneous velocity in the expression for the stress at the wall of a stationary flow. The unsteady part is a weighted average over the history of the flow acceleration, with a weighting function similar to that proposed by Vardy and Brown [J. Sound Vibr. 259, 1011 (2003); J. Sound Vibr. 270, 233 (2004)], but naturally including the effect of spatial derivatives of the mean flow, as in the Brunone model [Brunone et al., J. Water Res. Plan. Manage. 126, 236 (2000)].

Celebration of the Past--Challenge for the Future

ERIC Educational Resources Information Center

Black, Paul

2016-01-01

In this article, Paul Black reflects on his career's enrichment, due to the commitment of Kevin Keohane in the 1960s and 70s to reform the school science education. Black's commentary is based on a paper written by Kevin Keohane, ("Physics Education--21 Years On," 1987 "Phys. Educ." 22 142) where Keohane recalls the innovations…

Open Course Ware, Distance Education, and 21st Century Geoscience Education

NASA Astrophysics Data System (ADS)

Connors, M. G.

2010-12-01

Open Course Ware (OCW) allows the highest quality educational materials (including videos of lectures from the best classroom lecturers) to find a wide audience. This audience may include many who wish to obtain credentials for formal study yet who are unable to be campus-based students. This opens a role for formal, credentialed and accredited distance education (DE) to efficiently integrate OCW into DE courses. OCW materials will in this manner be able to be used for education of credential-seeking students who would not otherwise benefit from them. Modern presentation methods using the Internet and video (including mobile device) technologies may offer pedagogical advantages over even traditional classroom learning. A detailed analysis of the development of Athabasca University’s PHYS 302 Vibrations and Waves course (based mainly on MIT’s OCW), and application of lessons learned to development of PHYS 305 Electromagnetism is presented. These courses are relevant to the study of geophysics, but examples of GEOL (Geology) courses will also be mentioned, along with an broad overview of OCW resources in Geoscience.

Preparing Science Teachers for the future

NASA Astrophysics Data System (ADS)

Stein, Fredrick

2002-04-01

What will teachers need in the future to be successful? What will "successful" mean in the future? Are the teaching approaches learned 40 years ago still relevant for tomorrow's classrooms? Will technology really change the way physics is taught (K-16)? Will we close the performance gap between students of differing ethnicity? Are schools of education rising to the challenge to answer these questions? Can college and university physics departments rise to the challenge of presenting physics to all students in an engaging manner? What can the APS, in partnership with AAPT and AIP, do to find the answers and provide strategies to improve the science preparation of future teachers? PhysTEC aims to help physics and education faculty work together to provide an education for future teachers that emphasizes a student-centered, hands-on, inquiry-based approach to learning science. The compelling evidence produced from Physics Education Research warrants this approach. A National Science Foundation grant of 5.76 million and a 498 thousand grant from the Fund for the Improvement of Postsecondary Education support PhysTEC, its partners and activities. http://www.phystec.org/

Measuring Meaningful Outcomes in Consequential Contexts: Searching for a Happy Medium in Educational Technology Research (Phase II)

ERIC Educational Resources Information Center

Ross, Steven M.; Morrison, Jennifer R.

2014-01-01

In a paper published 25 years ago, Ross and Morrison ("Educ Technol Res Dev" 37(1):19-33, 1989) called for a "happy medium" in educational technology research, to be achieved by balancing high rigor of studies (internal validity) with relevance to real-world applications (external validity). In this paper, we argue that,…

Non-CMC Solutions of the Einstein Constraint Equations on Compact Manifolds with Apparent Horizon Boundaries

NASA Astrophysics Data System (ADS)

Holst, Michael; Meier, Caleb; Tsogtgerel, G.

2018-01-01

In this article we continue our effort to do a systematic development of the solution theory for conformal formulations of the Einstein constraint equations on compact manifolds with boundary. By building in a natural way on our recent work in Holst and Tsogtgerel (Class Quantum Gravity 30:205011, 2013), and Holst et al. (Phys Rev Lett 100(16):161101, 2008, Commun Math Phys 288(2):547-613, 2009), and also on the work of Maxwell (J Hyperbolic Differ Eqs 2(2):521-546, 2005a, Commun Math Phys 253(3):561-583, 2005b, Math Res Lett 16(4):627-645, 2009) and Dain (Class Quantum Gravity 21(2):555-573, 2004), under reasonable assumptions on the data we prove existence of both near- and far-from-constant mean curvature (CMC) solutions for a class of Robin boundary conditions commonly used in the literature for modeling black holes, with a third existence result for CMC appearing as a special case. Dain and Maxwell addressed initial data engineering for space-times that evolve to contain black holes, determining solutions to the conformal formulation on an asymptotically Euclidean manifold in the CMC setting, with interior boundary conditions representing excised interior black hole regions. Holst and Tsogtgerel compiled the interior boundary results covered by Dain and Maxwell, and then developed general interior conditions to model the apparent horizon boundary conditions of Dainand Maxwell for compact manifolds with boundary, and subsequently proved existence of solutions to the Lichnerowicz equation on compact manifolds with such boundary conditions. This paper picks up where Holst and Tsogtgerel left off, addressing the general non-CMC case for compact manifolds with boundary. As in our previous articles, our focus here is again on low regularity data and on the interaction between different types of boundary conditions. While our work here serves primarily to extend the solution theory for the compact with boundary case, we also develop several technical tools that have potential for use for other cases.

A multicharge ion source (Supernanogan) for the OLIS facility at ISAC/TRIUMF.

PubMed

Jayamanna, K; Wight, G; Gallop, D; Dube, R; Jovicic, V; Laforge, C; Marchetto, M; Leross, M; Louie, D; Laplante, R; Laxdal, R; McDonald, M; Wiebe, G J; Wang, V; Yan, F

2010-02-01

The Off-Line Ion Source (OLIS) [K. Jayamanna, D. Yuan, T. Kuo, M. MacDonald, P. Schmor, and G. Dutto, Rev. Sci. Instrum. 67, 1061 (1996); K. Jayamanna, Rev. Sci. Instrum. 79, 02711 (2008)] facility consists of a high voltage terminal containing a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source [K. Jayamanna and C. Vockenhuber, Rev. Sci. Instrum. 79, 02C712 (2008)], and an electrostatic switch that allows the selection of any one of the sources without mechanical intervention. These sources provide a variety of +1 beams up to mass 30 for Isotope Separator and ACcelerator (ISAC) [R. E. Laxdal, Nucl. Instrum. Methods Phys. Res. B 204, 400 (2003)] experiments, commissioning the accelerators, setting up the radioactive experiments, and for tuning the beam lines. The radio frequency quadrupole (RFQ) [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] injector accelerator is a constant velocity machine designed to accept only 2 keV/u and the source extraction energy is limited to 60 kV. Further stripping is then needed downstream of the RFQ to inject the beam into the drift tube linac [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] accelerator that requires A/q up to 6. Base on this constraints a multicharge ion source capable to deliver beams above mass 30 with A/q up to 6 was needed in order to reach full capability of the ISAC facility. A Supernanogan [C. Bieth et al., Nucleonika 48, S93 (2003)] multicharge ion source was then purchased from Pantechnik and was installed in the OLIS terminal. Commissioning and performance of the Supernanogan with some results such as emittance dependence of the charge states as well as charge state efficiencies are presented.

An Algebraic Construction of Duality Functions for the Stochastic {U_q( A_n^{(1)})} Vertex Model and Its Degenerations

NASA Astrophysics Data System (ADS)

Kuan, Jeffrey

2018-03-01

A recent paper (Kuniba in Nucl Phys B 913:248-277, 2016) introduced the stochastic U}_q(A_n^{(1)})} vertex model. The stochastic S-matrix is related to the R-matrix of the quantum group {U_q(A_n^{(1)})} by a gauge transformation. We will show that a certain function {D^+_{m intertwines with the transfer matrix and its space reversal. When interpreting the transfer matrix as the transition matrix of a discrete-time totally asymmetric particle system on the one-dimensional lattice Z , the function {D^+m} becomes a Markov duality function {Dm} which only depends on q and the vertical spin parameters μ_x. By considering degenerations in the spectral parameter, the duality results also hold on a finite lattice with closed boundary conditions, and for a continuous-time degeneration. This duality function had previously appeared in a multi-species ASEP(q, j) process (Kuan in A multi-species ASEP(q, j) and q-TAZRP with stochastic duality, 2017). The proof here uses that the R-matrix intertwines with the co-product, but does not explicitly use the Yang-Baxter equation. It will also be shown that the stochastic U}_q(A_n^{(1)})} is a multi-species version of a stochastic vertex model studied in Borodin and Petrov (Higher spin six vertex model and symmetric rational functions, 2016) and Corwin and Petrov (Commun Math Phys 343:651-700, 2016). This will be done by generalizing the fusion process of Corwin and Petrov (2016) and showing that it matches the fusion of Kulish and yu (Lett Math Phys 5:393-403, 1981) up to the gauge transformation. We also show, by direct computation, that the multi-species q-Hahn Boson process (which arises at a special value of the spectral parameter) also satisfies duality with respect to D_∞, generalizing the single-species result of Corwin (Int Math Res Not 2015:5577-5603, 2015).

Raman spectroscopy of triolein under high pressures

NASA Astrophysics Data System (ADS)

Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

2010-03-01

This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

A dichotomy in primary marine organic aerosol-cloud-climate system

NASA Astrophysics Data System (ADS)

Ceburnis, D.; Ovadnevaite, J.; Martucci, G.; Bialek, J.; Monahan, C.; Rinaldi, M.; Facchini, C.; Berresheim, H.; Worsnop, D. R.; O'Dowd, C.

2011-12-01

D. Ceburnis1, J. Ovadnevaite1, G. Martucci1, J. Bialek1, C. Monahan1, M. Rinaldi2, M. C. Facchini2, H. Berresheim1, D. R. Worsnop3,4 and C. D. O'Dowd1 1School of Physics & Centre for Climate and Air Pollution Studies, National University of Ireland Galway, University Road, Galway, Ireland 2Institute of Atmospheric Sciences and Climate, National Research Council, Bologna, 20129, Italy. 3 Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821-3976, USA 4 Physics Department, University of Helsinki, P.O. Box 64, 00014, Helsinki, Finland Organic matter has been observed to significantly contribute to particulate matter in every environment including pristine remote oceans. A significant if not dominant contribution of insoluble organic matter to marine aerosol has been proved to be of biogenic origin1,2. High time resolution measurements of marine organic matter have demonstrated a dynamic system with regular organic matter plume events occurring during summer3 as well as frequent open ocean particle formation events4. High-time resolution measurements of primary marine organic sea-spray physico-chemical properties reveal an apparent dichotomous behavior in terms of water uptake: specifically sea-spray aerosol enriched in organic matter possesses a low hygroscopic Growth Factor (GF~1.25) while simultaneously having a cloud condensation nucleus/condensation nuclei (CCN/CN) activation efficiency of between 83% at 0.25% supersaturation and 100% at 0.75%5. Simultaneous retrieval of Cloud Droplet Number Concentration (CDNC) during primary organic aerosol plumes reveal CDNC concentrations of 350 cm-3 in newly formed marine stratocumulus cloud for boundary layer organic mass concentrations of 3-4 ug m-36. It is suggested that marine hydrogels are responsible for this dichotomous behavior which has profound impacts to aerosol-cloud-climate system along with a better understood process analysis of aerosol formation by sea-spray7. A hydrophobic character of organic matter dominated aerosol in sub-saturated conditions should have significant implications for direct radiative effect while effectively forming cloud condensation nuclei should have significant contribution to indirect effect. 1 O'Dowd, C. D. et al. Nature 431, 676-680, doi:10.1038/Nature02959 (2004). 2 Ceburnis, D. et al. Atmos. Chem. Phys. Discuss. 11, 2749-2772, doi:doi:10.5194/acpd-11-2749-2011 (2011). 3 Ovadnevaite, J. et al. Geophys Res Lett 38, L02807, doi:10.1029/2010gl046083 (2011). 4 O'Dowd, C., et al. Geophys Res Lett 37, doi:L19805 10.1029/2010gl044679 (2010). 5 Ovadnevaite, J. et al. Geophys Res Lett (2011). 6 Martucci, G. and O'Dowd, C. D. Atmos. Meas. Tech. Discuss., 4, 4825-4865, doi:10.5194/amtd-4-4825-2011 (2011) 7 Gantt, B. et al. Atmos. Chem. Phys. Discuss. 11, 10525-10555, doi:10.5194/acpd-11-10525-2011 (2011).

What Can We Learn from PER: Physics Education Research?

ERIC Educational Resources Information Center

Singh, Chandralekha

2014-01-01

Physics Education Research (PER) focuses on understanding how students learn physics at all levels and developing strategies to help students with diverse prior preparations learn physics more effectively. New physics instructors are encouraged to visit http://PhysPort.org, a website devoted to helping instructors find effective teaching resources…

Electromagnetically Driven Plasma-Field Dynamics in Modified Ionosphere

NASA Astrophysics Data System (ADS)

Kochetov, Andrey; Terina, Galina

Under sounding of an artificial ionospheric turbulence by short probing radio pulses of ordinary polarization the two types of scattered signals were observed: a "caviton" signal (CS) and a "plasma" signal (PS), which appeared with the heating transmitter switching on and disap-peared after its switching off (G.I. Terina J. Atm. Terr. Phys, 57, 1995, 273, Izv. VUZov, Radiofizika, 39, 1998, 203). The scattered signal of PS type was revealed also after the heating switching off. It was called an "aftereffect plasma signal" (AEPS) (G.I. Terina Izv .VUZov, Radiofizika, 43, 2000, 958). This signal had large time and spatial delays and appeared mostly when corresponding PS had envelope fluctuations. The aftereffect phenomenon was expressed at time on CS by amplitude increasing at once after the heating transmitter turning off. The theoretical model of this phenomenon is proposed in and some peculiarities of the aftereffect phenomena of the scattered signals in modified ionospheric plasma are considered and discussed. For theoretical interpretation of the characteristics of CS and AEPS the numerical solution of nonlinear Shrüdinger equation (NSE) with driven extension were carried out in inhomogeneous plasma layer with linear electron density profile (A.V. Kochetov, V.A. Mironov, G.I. Terina, Adv. Space Reseacrh, 29, 2002, 1369) and for the one with prescribed density depletion (and A.V. Kochetov, G.I. Terina, Adv. Space Reseacrh, 38, 2006, 2490). The simulation results obtained for linear inhomogeneous plasma layer and for plasma one with density depletion al-low us to interpret the aftereffect of CS and PS qualitatively. The field amplitude increase at relaxation stage displayed at calculations allows us to interpret of CS aftereffect. The large time delays of AEPS can be explained as a result of powerful radio waves trapping in the forming at the plasma resonance regions density depletions (E. Mjøhus, J. Geophys. Res. 103, 1998, 14711; B. Eliasson and L. Stenflo, J. Geophys. Res., 113, 2008, A02305). It should be noted that PS and CS are analogous to different components of the stimulated electromagnetic emis-sion (SEE): "broad continuum" (BC) and narrow continuum" (NC) accordingly (see, e.g. (B. Isham, C. La Hoz, M.T. Rietveld, T. Hagfors, T.B. Leyser, Phys. Rev. Lett., 83, 1999, 2576)). AEPS is corresponded to Diagnostic SEE at the relaxation stage. The work was supported in part by RFBR grant 09-02-01150-a.

Periodicities in solar wind-magnetosphere coupling functions and geomagnetic activity during the past solar cycles

NASA Astrophysics Data System (ADS)

Andriyas, T.; Andriyas, S.

2017-09-01

In this paper, we study the solar-terrestrial relation through the wavelet analysis. We report periodicities common between multiple solar wind coupling functions and geomagnetic indices during five solar cycles and also and the strength of this correspondence. The Dst (found to be most predictable in Newell et al., J. Geophys. Res. Space Phys. 112(A1):A01206, 2007) and AL (least predictable in Newell et al., J. Geophys. Res. Space Phys. 112(A1):A01206, 2007) indices are used for this purpose. During the years 1966-2016 (which includes five solar cycles 20, 21, 22, 23, and 24), prominent periodicities ≤720 days with power above 95% confidence level were found to occur around 27, 182, 385, and 648 days in the Dst index while those in the AL index were found in bands around 27, 187, and 472 days. Ten solar wind coupling functions were then used to find periodicities common with the indices. All the coupling functions had significant power in bands centered around 27, 280, and 648 days while powers in fluctuations around 182, 385, and 472 days were only found in some coupling functions. All the drivers and their variants had power above the significant level in the 280-288 days band, which was absent in the Dst and AL indices. The normalized scale averaged spectral power around the common periods in the coupling functions and the indices indicated that the coupling functions most correlated with the Dst index were the Newell (27 and 385 days), Wygant (182 days), and Scurry-Russell and Boynton (648 days) functions. An absence of common power between the coupling functions and the Dst index around the annual periodicity was noted during the even solar cycles. A similar analysis for the AL index indicated that Newell (27 days), Rectified (187 days), and Boynton (472 days) were the most correlated functions. It was also found that the correlation numbers were relatively weaker for the AL index, specially for the 187 day periodicity. It is concluded that as the two indices respond to solar wind forcing with varying levels of strength at various prominent scales and the coupling function used, the response might be dependent on the scale (days or months or years) of interest at which the solar wind driving is to be predicted.

Charging and Discharging of Amorphous Solid Water Ice: Effects of Porosity

NASA Astrophysics Data System (ADS)

Bu, Caixia; Baragiola, Raul A.

2015-11-01

Introduction: Amorphous solid water (ASW) is abundant on Saturn’s icy satellites and rings [1,2], where it is subject to bombardment of energetic ions, electrons, and photons; together with secondary electron and ion emission, this may leave the surfaces charged. Surface potential can affect the flux of incoming charged particles, altering surface evolution. We examined the role of porosity [3] on electrostatic charging and discharging of ASW films at 30-140 K.Experiment: Experiments were performed in ultra-high vacuum [4]. ASW films were deposited at 30 K onto a liquid-He-cooled quartz crystal microbalance (QCM). Film porosity was calculated from the areal mass via the QCM and thickness via a UV-visible interferometry. ASW films were charged at 30 K using 500 eV He+. Surface potentials (Vs) of the films were measured with a Kelvin probe, and infrared spectra were collected using a Fourier transform infrared spectrometer.Results: We measured Vs of the ASW film at 30 K as a function of ion fluence (F). The Vs(F) deviates from a straight line at low fluence, attributed to emitted secondary electrons due to the negative polarization voltage [5,6], and increases linearly when the Vs is positive. We also measured Vs as a function of annealing temperature. We prepared ASW films with various porosities by annealing the films to different temperatures (Ta) prior to irradiation or varying the vapor-beam incidence angle (θ). Upon heating, we observed sharp decreases of the Vs at temperatures that strongly depend on Ta and θ. Decreases of the infrared absorbance of the dangling OH bands of the charged film share similar trends as that of the Vs. We propose a model that includes porosity for electrostatic charging/discharging of ASW films at temperatures below 100 K. Results are applicable to the study of plasma-surface interactions of icy satellites and rings.References: [1] Jurac et al., J. Geophys. Res. 100, 14821 (1995); [2] A. L. Graps et al., Space Sci. Rev. 137, 435 (2008); [3] U. Raut et al., J. Chem. Phys. 127, 204713 (2007); [4] C. Bu and R. B. Baragiola, J. Chem. Phys. 143, 074702 (2015); [5] C. Bu et al., J. Chem. Phys. 142, 134702 (2015); [6] M. J. Iedema et al., J. Phys. Chem. B 102, 9203 (1998).

Maser emission from planetary and stellar magnetospheres

NASA Astrophysics Data System (ADS)

Speirs, David

2012-07-01

A variety of astrophysical radio emissions have been identified to date in association with non-uniform magnetic fields and charged particle streams. From terrestrial auroral kilometric radiation (AKR) to observations of auroral radio emission from the flare star UV Ceti and CU Virginis, there are numerous examples of this intense, highly polarised magnetospheric radio signature [1][2]. Characterised by discrete spectral components at ~300kHz in the terrestrial auroral case, the radiation is clearly non-thermal and there is a strong belief that such emissions are generated by an electron cyclotron maser instability [1]. Previous work has focussed on a loss cone generation mechanism and cavity ducting model for radiation beaming, however recent theory and simulations suggest an alternative model comprising emission driven by an electron horseshoe distribution [1]. Such distributions are formed when particles descend into the increasing magnetic field of planetary / stellar auroral magnetospheres, where conservation of the magnetic moment results in conversion of axial momentum into rotational momentum. Theory has demonstrated that such distributions are highly unstable to cyclotron emission in the X-mode [3], and that these emissions when propagating tangential to the plasma cavity boundary may refract upwards due to plasma density inhomogeneity [4]. Scaled experiments have been conducted at the University of Strathclyde to study the emission process under controlled laboratory conditions [5]. In addition, numerical models have simulated the emission mechanism in the presence of a background plasma and in the absence of radiation boundaries [6]. Here we present the results of beam-plasma simulations that confirm the radiation model for tangential growth and upward refraction [4] and agree with recent Jodrell Bank observations of pulsed, narrowly beamed radio emission from the oblique rotator star CU Virginis [2]. [1] R. Bingham and R. A. Cairns, Phys. Plasmas, 7, 3089 (2000). [2] B.J. Kellett, V. Graffagnino, R. Bingham et al., ArXiv Astrophysics, 0701214 (2007). [3] R.A. Cairns, I. Vorgul, R. Bingham et al., Phys. Plasmas 18, 022902 (2011). [4] J.D. Menietti, R.L. Mutel, I.W. Christopher et al., J. Geophys. Res., 116, A12219 (2011). [5] S.L. McConville, M.E. Koepke, K.M. Gillespie et al., Plasma Phys. Control. Fusion, 53, 124020 (2011). [6] D.C. Speirs, K. Ronald, S.L. McConville, Phys. Plasmas, 17, 056501 (2010).

Scaling of convective dissolution in porous media

NASA Astrophysics Data System (ADS)

Hidalgo, Juan J.; Cueto-Felgueroso, Luis; Fe, Jaime; Juanes, Ruben

2012-11-01

Convective mixing in porous media results from the density increase in an ambient fluid as a substance (a solute or another fluid) dissolves into it., which leads to a Rayleigh-Bènard-type instability. The canonical model of convective mixing in porous media, which exhibits a dissolution flux that is constant during the time period before the convective fingers reach the bottom of the aquifer, is not described by the Rayleigh number Ra [Hidalgo & Carrera (2009), J. Fluid Mech.; Slim & Ramakrishnan (2010), Phys. Fluids]. That suggests that dissolution fluxes should not depend on Ra. However, this appears to be in contradiction with recent experimental results using an analogue-fluid system characterized by a non-monotonic density-concentration curve, which naturally undergoes convection [Neufeld et al. (2010), Geophys. Res. Lett.; Backhaus, Turitsyn & Ecke (2011), Phys. Rev. Lett.]. Here we study the scaling of dissolution fluxes by means of the variance of concentration and the scalar dissipation rate. The fundamental relations among these three quantities allow us to study the canonical and analogue-fluid systems with high-resolution numerical simulations, and to demonstrate that both the canonical and analogue-fluid systems exhibit a dissolution flux that is constant and independent of Ra. Our findings point to the need for alternative explanations of recent nonlinear scalings of the Nusselt number observed experimentally. JJH acknowledges the support from the FP7 Marie Curie Actions of the European Commission, via the CO2-MATE project (PIOF-GA-2009-253678).

Adaptive Quantum Control of Charge Motion in Semiconductor Heterostructures

NASA Astrophysics Data System (ADS)

Reitze, David

1998-05-01

Quantum control of electronic wavepacket motion and interactions using ultrafast lasers has moved from the conceptual stage to reality, in large part driven by advances in quantum control theory (R. J. Gordon and S. A. Rice, Ann. Rev. Phys. Chem. (1997), in press.) (M. Shapiro and P. Brumer, J. Chem. Soc. Faraday Trans. V93, 1263 (1997).) (D. Neuhauser and H. Rabitz, Acc. Chem. Res. V26, 496 (1993).) and experimental pulse shaping methods (A. M. Weiner, D. E. Leaird, G. P. Wiederrecht, and K. A. Nelson, Science V247, 412 (1990).) (A. Efimov, C. Schaffer, and D. H. Reitze, J. Opt. Soc. Am VB12, 1968 (1995).). Here, we apply these methods to controlling charge motion in semiconductor heterostructures. Control of coherent charge dynamics in heterostructures enjoys an advantage in that spatial potential profiles can be adjusted almost arbitrarily. Thus, control of charge motion can be exerted by tailoring both the temporal and spatial interactions of the charges with the controlling optical and static fields. In this talk, we demonstrate an experimental feedback loop which adaptively shapes fs pulses in a quantum contol pump-probe experiment, apply it to the control of coherent wavepacket motion in DC-biased asymmetric double quantum well(ADQW) structures, and compare to theoretical predictions of quantum control in ADQWs (N. M. Beach, D. H. Reitze, and J. L. Krause, submitted to Opt. Exp.) (J. L. Krause, D. H. Reitze, G. D. Sanders, A. Kuznetsov, and C. J. Stanton, to appear in Phys. Rev. B).

The Significance of Land-Atmosphere Processes in the Earth System

NASA Astrophysics Data System (ADS)

Suni, T.; Kulmala, M. T.; Guenther, A. B.

2012-12-01

The land-atmosphere interface is where humans primarily operate. Humans modify the land surface in many ways that influence the fluxes of energy and trace gases between land and atmosphere. Their emissions change the chemical composition of the atmosphere and anthropogenic aerosols change the radiative balance of the globe directly by scattering sunlight back to space and indirectly by changing the properties of clouds. Feedback loops among all these processes, land, the atmosphere, and biogeochemical cycles of nutrients and trace gases extend the human influence even further. Over the last decade, the importance of land-atmosphere processes and feedbacks in the Earth System has been shown on many levels and with multiple approaches, and a number of publications have shown the crucial role of the terrestrial ecosystems as regulators of climate [1-6]. Modellers have clearly shown the effect of missing land cover changes and other feedback processes and regional characteristics in current climate models and recommended actions to improve them [7-11]. Unprecedented insights of the long-term net impacts of aerosols on clouds and precipitation have also been provided [12-14]. Land-cover change has been emphasized with model intercomparison projects that showed that realistic land-use representation was essential in land surface modelling [11, 15]. Crucially important tools in this research have been the networks of long-term flux stations and large-scale land-atmosphere observation platforms that are also beginning to combine remote sensing techniques with ground observations [16-20]. Human influence has always been an important part of land-atmosphere science but in order to respond to the new challenges of global sustainability, closer ties with social science and economics groups will be necessary to produce realistic estimates of land use and anthropogenic emissions by analysing future population increase, migration patterns, food production allocation, land management practices, energy production, industrial development, and urbanization. Emphasis should be placed on, for instance, new observation networks incorporating remote sensing techniques with ground-based observations; the role of land-cover changes in modulating carbon, nitrogen, and hydrological cycles and, consequently, atmospheric chemistry, aerosol dynamics, and climate; regional (high-latitude) processes and their influence on global simulations; and interactions among anthropogenic and biogenic aerosols, clouds, and climate. 1. Ciais Ph 2005 Nature 2. Kulmala M et al 2004 Atmos Chem Phys 3. Philippon N et al 2005 J Geophys Res 4. Arneth A et al 2010a Nature Geoscience 5. Ganzeveld L et al 2010 J Geophys Res 6. Teuling A et al. 2010 Nature Geoscience 7. Arneth A et al 2010b Biogeosciences 8. Bonan GB et al. 2011 J Geophys Res 9. Davin EL and Seneviratne SI 2011 Biogeosciences 10. Pitman AJ et al 2011 Int J Clim 11. de Noblet-Ducoudré N et al 2012 J Clim 12. Rosenfeld D et al. 2008 Science 13. Stevens B and Feingold G 2009 Nature 14. Li Z et al 2011 Nature Geoscience 15. Pitman AJ et al 2009 Geophys Res Let 16. Baldocchi DD et al. 2005 Int J Biomet 17. Hari P et al 2009 Bor Env Res 18. Guenther A et al 2011 Bor Env Res 19. de Leeuw G et al. 2011 Biogeosciences 20. Jung M et al 2011 J Geophys Res

Asbestos in schools. Hearing before the Subcommittee on Transportation, Tourism, and Hazardous Materials on the Committee on Energy and Commerce, House of Representatives, One Hundredth Congress, First Session on H. J. Res. 153, February 19, 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-01-01

A hearing on H.J. Res. 153, under which the Environmental Protection Agency (EPA) would issue grants and loans to help school administrators finish the job of eliminating asbestos hazards from school buildings, included testimony from educators, school boards, citizen groups, and representatives of EPA. At issue was the administration's position that there is need for federal assistance for the clean-up, and that previous federal expenditures have been adequate. Witnesses explored the financial problems local schoold face in removing the asbestos and their need for further help. The hearing record includes the test of H.J. Res. 153, the testimony of themore » nine principal witnesses, and additional material submitted for the record.« less

The Use of Lego Technologies in Elementary Teacher Preparation

ERIC Educational Resources Information Center

Hadjiachilleos, Stella; Avraamidou, Lucy; Papastavrou, Stavros

2013-01-01

The need to reform science teacher preparation programs has been pointed out in research (Bryan and Abell in "J Res Sci Teach" 36:121-140, 1999; Bryan and Atwater in "Sci Educ" 8(6):821-839, 2002; Harrington and Hathaway in "J Teach Educ" 46(4):275-284, 1995). Science teachers are charged with the responsibility of…

Globalisation and Science Education: The Case of "Sustainability by the Bay"

ERIC Educational Resources Information Center

Carter, Lyn; Dediwalage, Ranjith

2010-01-01

It is impossible to consider contemporary science education in isolation from globalisation as the dominant logic, rethinking and reconfiguring social and cultural life in which it is located. Carter (J Res Sci Teach 42, 561-580, "2005") calls for a close reading of policy documents, curriculum projects, research studies and a range of other…

Cinema, Fermi Problems and General Education

ERIC Educational Resources Information Center

Efthimiou, C. J.; Llewellyn, R. A.

2007-01-01

During the past few years the authors have developed a new approach to the teaching of physical science, a general education course typically found in the curricula of nearly every college and university. This approach, called "Physics in Films" (Efthimiou and Llewellyn 2006 Phys. Teach. 44 28-33), uses scenes from popular films to illustrate…

Asymmetric kinetic equilibria: Generalization of the BAS model for rotating magnetic profile and non-zero electric field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorville, Nicolas, E-mail: nicolas.dorville@lpp.polytechnique.fr; Belmont, Gérard; Aunai, Nicolas

Finding kinetic equilibria for non-collisional/collisionless tangential current layers is a key issue as well for their theoretical modeling as for our understanding of the processes that disturb them, such as tearing or Kelvin Helmholtz instabilities. The famous Harris equilibrium [E. Harris, Il Nuovo Cimento Ser. 10 23, 115–121 (1962)] assumes drifting Maxwellian distributions for ions and electrons, with constant temperatures and flow velocities; these assumptions lead to symmetric layers surrounded by vacuum. This strongly particular kind of layer is not suited for the general case: asymmetric boundaries between two media with different plasmas and different magnetic fields. The standard methodmore » for constructing more general kinetic equilibria consists in using Jeans theorem, which says that any function depending only on the Hamiltonian constants of motion is a solution to the steady Vlasov equation [P. J. Channell, Phys. Fluids (1958–1988) 19, 1541 (1976); M. Roth et al., Space Sci. Rev. 76, 251–317 (1996); and F. Mottez, Phys. Plasmas 10, 1541–1545 (2003)]. The inverse implication is however not true: when using the motion invariants as variables instead of the velocity components, the general stationary particle distributions keep on depending explicitly of the position, in addition to the implicit dependence introduced by these invariants. The standard approach therefore strongly restricts the class of solutions to the problem and probably does not select the most physically reasonable. The BAS (Belmont-Aunai-Smets) model [G. Belmont et al., Phys. Plasmas 19, 022108 (2012)] used for the first time the concept of particle accessibility to find new solutions: considering the case of a coplanar-antiparallel magnetic field configuration without electric field, asymmetric solutions could be found while the standard method can only lead to symmetric ones. These solutions were validated in a hybrid simulation [N. Aunai et al., Phys. Plasmas (1994-present) 20, 110702 (2013)], and more recently in a fully kinetic simulation as well [J. Dargent and N. Aunai, Phys. Plasmas (submitted)]. Nevertheless, in most asymmetric layers like the terrestrial magnetopause, one would indeed expect a magnetic field rotation from one direction to another without going through zero [J. Berchem and C. T. Russell, J. Geophys. Res. 87, 8139–8148 (1982)], and a non-zero normal electric field. In this paper, we propose the corresponding generalization: in the model presented, the profiles can be freely imposed for the magnetic field rotation (although restricted to a 180 rotation hitherto) and for the normal electric field. As it was done previously, the equilibrium is tested with a hybrid simulation.« less

Career Outcomes of Graduates of R25E Short-Term Cancer Research Training Programs.

PubMed

Desmond, Renee A; Padilla, Luz A; Daniel, Casey L; Prickett, Charles T; Venkatesh, Raam; Brooks, C Michael; Waterbor, John W

2016-03-01

The efficacy of short-term cancer research educational programs in meeting its immediate goals and long-term cancer research career objectives has not been well studied. The purpose of this report is to describe the immediate impact on, and the long-term career outcomes of, 499 medical students and graduate students who completed the Cancer Research Experiences for Students (CaRES) program at the University of Alabama at Birmingham (UAB) from 1999 to 2013. In summer 2014, all 499 program alumni were located and 96.4 % (481 of 499) agreed to complete a longitudinal tracking survey. About 23 % of CaRES alumni (110 of 499) have published at least one cancer-related paper. Overall 238 cancer-related papers have been published by CaRES alumni, one third of this number being first-authored publications. Nearly 15 % (71 of 481 respondents) reported that their current professional activities include cancer research, primarily clinical research and outcomes research. Of these 71 individuals, 27 (38 %) have completed their training and 44 (62 %) remain in training. Of all respondents, 58 % reported that they administered care to cancer patients and 30 % reported other cancer-related professional responsibilities such as working with a health department or community group on cancer control activities. Of the 410 respondents not currently engaged in cancer research, 118 (29 %) stated intentions to conduct cancer research in the next few years. Nearly all respondents (99.6 %) recommended CaRES to today's students. Challenging short-term educational cancer research programs for medical students and graduate health professional students can help them refine and solidify their career plans, with many program alumni choosing cancer research careers.

Long-term Field Experiments as Important Source of Knowledge - Aims of the BonaRes Data Centre

NASA Astrophysics Data System (ADS)

Grosse, Meike; Hierold, Wilfried

2017-04-01

BonaRes is short for "soil as a sustainable resource for the bioeconomy". It is funded by the German Federal Ministry of Education and Research (BMBF) under the umbrella of the National Research Strategy BioEconomy 2030. BonaRes consists of ten interdisciplinary research project consortia and the 'BonaRes - Centre for Soil Research' (see also Wollschläger et al 2016). It is one task of the BonaRes Data Centre as part of the 'BonaRes - Centre for Soil Research', to collect data and meta-data of agricultural long-term field experiments (LTFE) in Germany. The definition of LTFE in the context of BonaRes is a minimum duration of twenty years and a static design. LTFE are essential research infrastructures for agricultural sciences and soil sciences amongst other disciplines. Some LTFE run since a very long time; the start of the oldest one in Germany was 1878. Therefore, in many cases valuable time series exist. Data sets of LTFE shall be compiled and made publicly available by the BonaRes Data Centre. The public availability together with an easy access will lead to an enhanced usability of the data. This probably makes the LTFE itself more valuable through an improved visibility and may also help to maintain the LTFE. Beyond the data compilation there is the possibility for every data owner to make a data publication, which offers an additional value for the data owner after his first right of use. A first step towards a joint database is a compilation of all existing LTFE in Germany with meta information to each trial. This information is shown in an interactive web map, what is completely new in that context. Besides the exact position of the LTFE the following metadata are shown: name of the LTFE, website (if available), institution, land use category, participation in existing networks, research theme, start (and maybe end) of the trial, and research parameters. Details on the meta information will be presented in the speech. Literature Wollschläger, U; Helming, K.; Heinrich, U.; Bartke, S.; Kögel-Knabner, I.; Russell, D.; Eberhardt, E. & Vogel, H.-J. (2016): The BonaRes Centre - A virtual institute for soil research in the context of a sustainable bio-economy. Geophysical Research Abstracts Vol. 18, EGU2016-9087, http://meetingorganizer.copernicus.org/EGU2016/EGU2016-9087.pdf.

Bounce—the answer

NASA Astrophysics Data System (ADS)

Featonby, David

2018-05-01

In my article (Featonby 2018 Phys. Educ. 53 027002) Three experiments were presented which involved dropping objects and observing the “bounce”. The question was, for each object, can you predict what might happen and explain the differences.

Potatoes and elastic—the answer

NASA Astrophysics Data System (ADS)

Featonby, D.

2018-07-01

In my article (Featonby 2018 Phys. Educ. 53 037002) we asked what happens when two objects connected by elastic are held vertically, so that the elastic is stretched, and dropped. Which object reaches the ground first.

To b or not to b ?? A nonextensive view of b-value in the Gutenberg-Richter law.

NASA Astrophysics Data System (ADS)

Vallianatos, Filippos

2014-05-01

The Gutenberg-Richter (GR) (Gutenberg and Richter, 1944) law one of the cornerstones of modern seismology has been considered as a paradigm of manifestation of self-organized criticality since the dependence of the cumulative number of earthquakes with energy, i.e., the number of earthquakes with energy greater than E, behaves as a power law with the b value related to the critical exponent. A great number of seismic hazard studies have been originated as a result of this law. The Gutenberg-Richter (GR) law is an empirical relationship, which recent efforts relate it with general physical principles (Kagan and Knopoff, 1981; Wesnousky, 1999; Sarlis et al., 2010; Telesca, 2012; Vallianatos and Sammonds, 2013). Nonextensive statistical mechanics pioneered by Tsallis (Tsallis, 2009) provides a consistent theoretical framework for the studies of complex systems in their nonequilibrium stationary states, systems with multi fractal and self-similar structures, long-range interacting systems, etc. Earth is such system. In the present work we analyze the different pathways (originated in Sotolongo-Costa, A. Posadas , 2004; Silva et al., 2006) to extract the generalization of the G-R law as obtained in the frame of non extensive statistical physics. We estimate the b-value and we discuss its underline physics. This research has been funded by the European Union (European Social Fund) and Greek national resources under the framework of the "THALES Program: SEISMO FEAR HELLARC" project of the "Education & Lifelong Learning" Operational Programme. References Gutenberg, B. and C. F. Richter (1944). Bull. Seismol. Soc. Am. 34, 185-188. Kagan, Y. Y. and L. Knopoff (1981). J. Geophys. Res. 86, 2853-2862. Sarlis, N., E. Skordas and P. Varotsos (2010). Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 82 (2) , 021110. Silva, R., G. Franca, C. Vilar and J. Alcaniz (2006). Phys. Rev. E, 73, 026102 Sotolongo-Costa, O. and A. Posadas (2004). Phys. Rev. Lett., 92, 048501 Telesca, L. (2012). Bull. Seismol. Soc. Amer., 102,886-891. Tsallis, C. (2009). Introduction to Nonextensive Statistical Mechanics, Approaching a Complex World Springer, New York Vallianatos, F. and P. Sammonds, (2013). Tectonophysics 590, 52-58 Wesnousky, S. G. (1999). Bull. Seismol. Soc. Am. 89, 1131-1137.

Information transfer across the scales of climate variability: The effect of the 7-8 year cycle on the annual and interannual scales

NASA Astrophysics Data System (ADS)

Palus, Milan; Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, Sergey; Tsonis, Anastasios

2016-04-01

Complexity of the climate system stems not only from the fact that it is variable over a huge range of spatial and temporal scales, but also from the nonlinear character of the climate system that leads to interactions of dynamics across scales. The dynamical processes on large time scales influence variability on shorter time scales. This nonlinear phenomenon of cross-scale causal interactions can be observed due to the recently introduced methodology [1] which starts with a wavelet decomposition of a multi-scale signal into quasi-oscillatory modes of a limited bandwidth, described using their instantaneous phases and amplitudes. Then their statistical associations are tested in order to search for interactions across time scales. An information-theoretic formulation of the generalized, nonlinear Granger causality [2] uncovers causal influence and information transfer from large-scale modes of climate variability with characteristic time scales from years to almost a decade to regional temperature variability on short time scales. In analyses of air temperature records from various European locations, a quasioscillatory phenomenon with the period around 7-8 years has been identified as the factor influencing variability of surface air temperature (SAT) on shorter time scales. Its influence on the amplitude of the SAT annual cycle was estimated in the range 0.7-1.4 °C and the effect on the overall variability of the SAT anomalies (SATA) leads to the changes 1.5-1.7 °C in the annual SATA means. The strongest effect of the 7-8 year cycle was observed in the winter SATA means where it reaches 4-5 °C in central European station and reanalysis data [3]. This study is supported by the Ministry of Education, Youth and Sports of the Czech Republic within the Program KONTAKT II, Project No. LH14001. [1] M. Palus, Phys. Rev. Lett. 112 078702 (2014) [2] M. Palus, M. Vejmelka, Phys. Rev. E 75, 056211 (2007) [3] N. Jajcay, J. Hlinka, S. Kravtsov, A. A. Tsonis, M. Palus, Time-scales of the European surface air temperature variability: The role of the 7-8 year cycle. Geophys. Res. Lett., in press, DOI: 10.1002/2015GL067325

Exploring a Model of Situated Professional Development: Impact on Classroom Practice

ERIC Educational Resources Information Center

Singer, Jonathan; Lotter, Christine; Feller, Robert; Gates, Harry

2011-01-01

A hallmark of current science education reform involves teaching through inquiry. However, the widespread use of inquiry-based instruction in many classrooms has not occurred (Roehrig and Luft in "Int J Sci Educ" 26:3-24, 2004; Schneider et al. in "J Res Sci Teach" 42:283-312, 2005). The purpose of this study was to investigate the impact of a…

Toward Re-Thinking Science Education in Terms of Affective Practices: Reflections from the Field

ERIC Educational Resources Information Center

Kayumova, Shakhnoza; Tippins, Deborah

2016-01-01

Rational and operationalized views of science and what it means for teachers and students to know and enact legitimate science practices have dominated science education research for many decades (Fusco and Barton in "J Res Sci Teach" 38(3):337-354, 2001. doi: 10.1002/1098-2736(200103)38:3<337::AID-TEA1009>3.0.CO;2-0). Michalinos…

Health Care and Education Reconciliation Act of 2010 (Public Law 111-152)

ERIC Educational Resources Information Center

US Congress, 2010

2010-01-01

The Health Care and Education Reconciliation Act of 2010 (Public Law 111-152) was put in place to provide for reconciliation pursuant to Title II of the concurrent resolution on the budget for fiscal year 2010 (S. Con. Res. 13). The table of contents for this Act is as follows: (1) Sec. 1. Short title; table of contents. (A) Title--Coverage,…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, J.H.; Wilson, W.E.

The beads on a string model proposed by Ganguly and Magee (A.K. Ganguly and J.L. Magee, J. Chem. Phys. 25, 129 (1956)) was generalized to allow Monte Carlo techniques to be used in calculating the influence of track structure on the yield of free radicals at early times following energy deposition by ionizing radiation in aqueous solutions. The results of the Monte Carlo calculations can be interpreted in terms of an effective linear energy transfer (LET) that is significantly less than the stopping power of the radiation when the track structure has a diffuse radial distribution due to energy transportmore » by delta-rays. By incorporating this effective LET for deuterons and alpha particles into a one radical approximation, the model can account for the effect of track structure on the yield of hydrated electrons measured by Sauer and co-workers (M.C. Sauer, Jr., K.H. Schmidt, E.J. Hart, C.A. Naleway and C.D. Jonah, Radiat. Res. 70, 91 (1977)).« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, J.H.; Wilson, W.E.

The beads on a string model proposed by Ganguly and Magee (A.K. Ganguly and J.L. Magee, J. Chem. Phys. 25, 129(1956)) was generalized to allow Monte Carlo techniques to be used in calculating the influence of track structure on the yield of free radicals at early times following energy deposition by ionizing radiation in aqueous solutions. The results of the Monte Carlo calculations can be interpreted in terms of an effective linear energy transfer (LET) that is significantly less than the stopping power of the radiation when the track structure has a diffuse radial distribution due to energy transport bymore » delta-rays. By incorporating this effective LET for deuterons and alpha particles into a one radical approximation, the model can account for the effect of track structure on the yield of hydrated electrons measured by Sauer and co-workers (M.C. Sauer, Jr., K.H. Schmidt, E.J. Hart, C.A. Naleway and C.D. Jonah, Radiat. Res. 70, 91(1977)). 3 figures.« less

Robust numerical simulation of porosity evolution in chemical vapor infiltration III: three space dimension

NASA Astrophysics Data System (ADS)

Jin, Shi; Wang, Xuelei

2003-04-01

Chemical vapor infiltration (CVI) process is an important technology to fabricate ceramic matrix composites (CMC's). In this paper, a three-dimension numerical model is presented to describe pore microstructure evolution during the CVI process. We extend the two-dimension model proposed in [S. Jin, X.L. Wang, T.L. Starr, J. Mater. Res. 14 (1999) 3829; S. Jin. X.L. Wang, T.L. Starr, X.F. Chen, J. Comp. Phys. 162 (2000) 467], where the fiber surface is modeled as an evolving interface, to the three space dimension. The 3D method keeps all the virtue of the 2D model: robust numerical capturing of topological changes of the interface such as the merging, and fast detection of the inaccessible pores. For models in the kinetic limit, where the moving speed of the interface is constant, some numerical examples are presented to show that this three-dimension model will effectively track the change of porosity, close-off time, location and shape of all pores.

Experimental verification of a gain reduction model for the space charge effect in a wire chamber

NASA Astrophysics Data System (ADS)

Nagakura, Naoki; Fujii, Kazuki; Harayama, Isao; Kato, Yu; Sekiba, Daiichiro; Watahiki, Yumi; Yamashita, Satoru

2018-01-01

A wire chamber often suffers significant saturation of the multiplication factor when the electric field around its wires is strong. An analytical model of this effect has previously been proposed [Y. Arimoto et al., Nucl. Instrum. Meth. Phys. Res. A 799, 187 (2015)], in which the saturation was described by the multiplication factor, energy deposit density per wire length, and one constant parameter. In order to confirm the validity of this model, a multi-wire drift chamber was developed and irradiated by a MeV-range proton beam at the University of Tsukuba. The saturation effect was compared for energy deposits ranging from 70 keV/cm to 180 keV/cm and multiplication factors 3× 103 to 3× 104. The chamber was rotated with respect to the proton beam in order to vary the space charge density around the wires. The energy deposit distribution corrected for the effect was consistent with the result of a Monte Carlo simulation, thus validating the proposed model.

Elastic positron scattering by C{sub 2}H{sub 2}: Differential cross sections and virtual state formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carvalho, Claudia R.C. de; Varella, Marcio T. do N; Lima, Marco A.P.

2003-12-01

We present calculated elastic differential cross sections for positron-acetylene scattering, obtained by using the Schwinger multichannel method. Our results are in very good agreement with quasielastic experimental data of Kauppila et al. [Nucl. Instrum. Meth. Phys. Res. B 192, 162 (2002)]. We also discuss the existence of a virtual state (zero-energy resonance) in e{sup +}-C{sub 2}H{sub 2} collisions, based on the behavior of the integral cross section and of the s-wave phase shift. As expected the fixed-nuclei cross section and annihilation parameter (Z{sub eff}) present the same energy dependence at very low impact energies. As the virtual state energy approachesmore » zero, the magnitude of both cross section and Z{sub eff} are extremely enhanced (at zero impact energy). The possibility of shifting from a low-lying virtual state to a shallow bound state is not expected to significantly affect room-temperature annihilation rates.« less

Investigating the heterogeneous freezing behavior of supercooled droplets containing different amounts of SNOMAX

NASA Astrophysics Data System (ADS)

Niedermeier, D.; Budke, C.; Koop, T.; Hartmann, S.; Augustin, S.; Stratmann, F.; Wex, H.

2013-12-01

Heterogeneous ice nucleation, a fundamental process for ice formation in the atmosphere, has been observed to occur in clouds at temperatures higher than -20 °C (Kanitz et al., 2011). However, laboratory studies showed that mineral dust particles, which are the most abundant atmospheric ice nuclei (IN), are ice active at lower temperature (Murray et al., 2012). Biological particles such as bacteria nucleate ice at higher temperatures similar to those observed in the atmosphere. But their atmospheric relevance is controversially discussed (Hartmann et al., 2013; Hoose et al., 2010). In order to achieve a better understanding, fundamental processes underlying ice nucleation on bacteria should be investigated. Within the Ice Nuclei research UnIT (INUIT), the ice nucleating ability of SNOMAX, which contains non-viable Pseudomonas syringae bacteria as well as their fragments, was quantified using different measurement devices featuring different measurement techniques. Here, results determined with the Bielefeld Ice Nucleation ARraY (BINARY, Budke et al., 2013) and the Leipzig Aerosol Cloud Interaction Simulator (LACIS, Hartmann et al., 2011) are presented exemplarily. Within these devices, droplets with different amounts of SNOMAX were exposed to supercooling temperatures until they froze (BINARY: cooling rate: 1K/min; LACIS: residence time of supercooled droplets at a certain temperature: ~0.2s). Frozen fractions were determined in a temperature range of ca. -4 to -20 °C. These fractions increase steeply and, in part, level off at values lower than 100% (i.e., they reach a plateau value indicating the number of SNOMAX IN per droplet) depending on the SNOMAX concentration. With increasing amount of SNOMAX per droplet, the frozen fraction curve is shifted to higher temperature and the plateau value increases, reaching 100% for the highest SNOMAX concentrations. It has been suggested that ice nucleation active (INA) macromolecules, i.e. protein complexes in the case of bacteria, initiate the freezing process (Wolber et al. 1986). The Soccer ball model (Niedermeier et al., 2011) was used to parameterize the ice nucleation behavior of these INA macromolecules. One parameter set (mean contact angle and its standard deviation) could be derived that matches the experimental results of both devices. This parameterization can be used to describe the ice nucleation behavior of the INA bacteria in atmospheric models for a given number concentration being present in the atmosphere. Acknowledgement This work is funded by the German Research Foundation (DFG projects WE 4722/1-1 and KO 2944/2-1, both part of the research unit INUIT). References Budke et al., Proc.19th ICNAA, Fort Collins, CO, USA, 949-951, 2013. Hartmann et al., Atmos. Chem. Phys., 11, 1753-1767, 2011. Hartmann et al., Atmos. Chem. Phys., 13, 5751-5766, 2013. Hoose et al., Environ. Res. Lett. 5, 024009, 2010. Kanitz et al., Geophys. Res. Lett., 38, L17802, 2011. Niedermeier et al., Atmos. Chem. Phys., 11, 8767-8775, 2011. Murray et al., Chem. Soc. Rev., 41, 6519-6554, 2012. Wolber et al., P. Natl. A. Sci., 83, 7256-7260, 1986.

Laboratory Studies of FeO and NiO Chemiluminescence

NASA Astrophysics Data System (ADS)

Kalogerakis, K. S.; Bartlett, N. C.; Copeland, R. A.; Slanger, T. G.

2013-12-01

Although the terrestrial nightglow spectrum has been studied for over a century, new identifications of spectral features continue to be made. Recently, FeO* continuum emissions in the mesosphere were identified by comparison of results from the OSIRIS spectrometer to existing laboratory spectra [1]. This discovery has sparked a renewal of interest in the reactions of meteoric metals with mesospheric gases [2,3], and has motivated the current study. We report laboratory-based chemiluminescence spectra from the reactions Fe + O3 and Ni + O3 produced under various conditions. Iron and nickel vapor was prepared in a vacuum cell using laser ablation at 248 and 800 nm in the presence of ozone. Emission spectra from FeO* and NiO* were recorded in the region of 450-700 nm using a commercial fiber-coupled spectrometer and compared to previous results using different methods. Knowledge of the excited-state production efficiency of Fe + O3 → FeO* + O2 and the analogous reaction with Ni is critical in modeling upper atmospheric dynamics of meteoric metal layers. The only relevant experimental study in the literature for iron oxide is from West and Broida [4], who reported a yield of approximately 2% at around 1 Torr, in stark contrast with the 100% efficiency used in relevant model calculations [5]. This work was supported by the National Science Foundation's Aeronomy Program under grant AGS-0637433. References 1. W.F.J. Evans, R.L. Gattinger, T.G. Slanger, D.V. Saran, D.A. Degenstein, and E.J. Llewellyn, Geophys. Res. Lett., 37, L22105 (2010). 2. D.V. Saran, T.G. Slanger, W. Feng, and J.M.C. Plane, J. Geophys. Res. 116, D12303 (2011). 3. R.L. Gattinger, W.F.J. Evans, and E.J. Llewellyn, Canadian Journal of Physics 89, 869 (2011). 4. J.B. West and H.P. Broida, J. Chem. Phys. 62, 2566 (1975 ). 5. C.S. Gardner, J.M.C. Plane, W.L. Pan, T. Vondrak, B.J. Murray, and X.Z. Chu, J. Geophys. Res. 110, D10302 (2005).

Quantifying apparent anisotropy in a chemically heterogeneous Earth's mantle

NASA Astrophysics Data System (ADS)

Faccenda, M.; Ferreira, A. M.; Lithgow-Bertelloni, C. R.; Stixrude, L. P.; Pennacchioni, G.

2017-12-01

The interpretation of seismic observations of anisotropy is not straightforward. For example, it is well established that a finely layered, purely isotropic medium is equivalent at large scale to a homogeneous anisotropic medium (Backus, 1962) and there is seismological evidence for fine layered media, such as quasi-laminated structures constrained from high-frequency scattered waves (e.g., Furumura and Kennett, 2005; Kennett and Furumura, 2008). Thus, when imaging fine layering with seismic wave data with wavelength larger than the layer's thickness may result in artificial (also called apparent) anisotropy. Recent studies identified families of stable fine scale models that are equivalent to long-wavelength, vertically transversely isotropic (VTI) models (Fichtner et al., 2013; Wang et al., 2013; Bodin et al., 2015), and efforts to consider more general media are currently under way (e.g., Capdeville et al., 2010a,b). However, it is not clear whether the equivalent fine scale models are compatible with the properties of Earth's mantle materials. In this contribution, we quantify apparent anisotropy arising from fine layering by considering a range of realistic Earth's compositions both at grain and rock scale. We show that significant apparent anisotropy can be formed in ideal conditions only in very narrow regions, while in most of the Earth's mantle apparent anisotropy will hardly be detectable. ReferencesBackus, G.E., 1962. J. Geophys. Res. 67, 4427-4440. Bodin, T., Capdeville, Y., Romanowicz, B. & Montagner, J.-P., 2015. In The Earth's Heterogeneous Mantle, pp. 105-144, eds Khan, A. & Deschamps, F., Springer. Capdeville, Y., Guillot, L., Marigo, J.J., 2010a. Geophys. J. Int. 182, 903-922. Capdeville, Y., Guillot, L., Marigo, J.J., 2010b. Geophys. J. Int. 181, 897-910. Fichtner, A., B. Kennett, and J. Trampert, 2013. Phys. Earth Planet. Inter., 219, 11-20. Furumura, T., Kennett, B.L.N., 2005. J. Geophys. Res. 110, 10.129/2004JB003486. Kennett, B.L.N., Furumura, T., 2008. Geophys. J. Int. 172, 363-382. Wang, N., Montagner J.-P., Fichtner, A., Capdeville, Y., 2013. Geophys. Res. Lett. 40, 4284-4288.

Genetic Pedagogical Content Knowledge (PCK) Ability Profile of Prospective Biology Teacher

NASA Astrophysics Data System (ADS)

Purwianingsih, W.; Muthmainnah, E.; Hidayat, T.

2017-02-01

Genetics is one of the topics or subject matter in biology that are considered difficult. Student difficulties of understanding genetics, can be caused by lack of understanding this concept and the way of teachers teach. Pedagogical Content Knowledge (PCK) is a way to understand the complex relationships between teaching and content taught through the use of specific teaching approaches. The aims of study was to analyze genetic PCK ability profile of prospective biology teacher.13 student of sixth semester Biology education department who learned Kapita Selekta Biologi SMA course, participated in this study. PCK development was measured by CoRes (Content Representation). Before students fill CoRes, students are tested mastery genetic concepts through a multiple-choice test with three tier-test. Data was obtained from the prior CoRes and its revisions, as well as the mastery concept in pre and post test. Results showed that pre-test of genetic mastery concepts average on 55.4% (low category) and beginning of the writing CoRes, student get 43.2% (Pra PCK). After students get lecture and simulating learning, the post-test increased to 63.8% (sufficient category) and PCK revision is also increase 58.1% (growing PCK). It can be concluded that mastery of subject matter could affects the ability of genetic PCK.

Further thoughts on the solar constant

NASA Astrophysics Data System (ADS)

Thompson, Frank

2018-05-01

I read with interest the recent paper (Brizova and Slegr 2017 Phys. Educ. 52 013008) regarding an experiment to measure the solar constant using a bolometer. The authors admitted that their measurements gave a value much lower than expected.

Total ozone patterns over the northern mid-latitudes: spatial correlations, extreme events and dynamical contributions

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Staehelin, J.; Maeder, J. A.; Ribatet, M.; Bodeker, G. E.; Davison, A. C.

2009-04-01

Tools from geostatistics and extreme value theory are applied to analyze spatial correlations in total ozone for the northern mid-latitudes. The dataset used in this study is the NIWA combined total ozone dataset (Bodeker et al., 2001; Müller et al., 2008). New tools from extreme value theory (Coles, 2001; Ribatet, 2007) have recently been applied to the world's longest total ozone record from Arosa, Switzerland (e.g. Staehelin 1998a,b), in order to describe extreme events in low and high total ozone (Rieder et al., 200x). Within the current study, patterns in spatial correlation and frequency distributions of extreme events (e.g. ELOs and EHOs) are studied for the northern mid-latitudes. New insights in spatial patterns of total ozone for the northern mid-latitudes are presented. Koch et al. (2005) found that the increase in fast isentropic transport of tropical air to northern mid-latitudes contributed significantly to ozone changes between 1980 and 1989. Within this study the influence of changes in atmospheric dynamics (e.g. tropospheric and lower stratospheric pressure systems) on column ozone over the northern mid-latitudes is analyzed for the time period 1979-2007. References: Bodeker, G.E., J.C. Scott, K. Kreher, and R.L. McKenzie, Global ozone trends in potential vorticity coordinates using TOMS and GOME intercompared against the Dobson network: 1978-1998, J. Geophys. Res., 106 (D19), 23029-23042, 2001. Coles, S.: An Introduction to Statistical Modeling of Extreme Values, Springer Series in Statistics, ISBN:1852334592, Springer, Berlin, 2001. Koch, G., H. Wernli, C. Schwierz, J. Staehelin, and T. Peter (2005), A composite study on the structure and formation of ozone miniholes and minihighs over central Europe, Geophys. Res. Lett., 32, L12810, doi:10.1029/2004GL022062. Müller, R., Grooß, J.-U., Lemmen, C., Heinze, D., Dameris, M., and Bodeker, G.: Simple measures of ozone depletion in the polar stratosphere, Atmos. Chem. Phys., 8, 251-264, 2008. Ribatet, M.: POT: Modelling peaks over a threshold, R News, 7, 34-36, 2007. Rieder, H.E., Staehelin, J., Maeder, J.A., Ribatet, M., Stübi, R., Weihs, P., Holawe, F., Peter, T., and Davison, A.C.: From ozone mini holes and mini highs towards extreme value theory: New insights from extreme events and non stationarity, submitted to J. Geophys. Res., 200x. Staehelin, J., Kegel, R., and Harris, N. R.: Trend analysis of the homogenized total ozone series of Arosa (Switzerland), 1929-1996, J. Geophys. Res., 103(D7), 8389-8400, doi:10.1029/97JD03650, 1998a. Staehelin, J., Renaud, A., Bader, J., McPeters, R., Viatte, P., Hoegger, B., Bugnion, V., Giroud, M., and Schill, H.: Total ozone series at Arosa (Switzerland): Homogenization and data comparison, J. Geophys. Res., 103(D5), 5827-5842, doi:10.1029/97JD02402, 1998b.

Photovoltaic reciprocity and quasi-Fermi level splitting in nanostructure-based solar cells (Conference Presentation)

NASA Astrophysics Data System (ADS)

Aeberhard, Urs

2017-04-01

The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions [1]. So far, the theory has been verified for a wide range of devices and material systems and forms the basis of a growing number of luminesecence imaging techniques used in the characterization of photovoltaic materials, cells and modules [2-5]. However, there are also some examples where the theory fails, such as in the case of amorphous silicon. In our contribution, we critically assess the assumptions made in the derivation of the theory and compare its predictions with rigorous formal relations as well as numerical computations in the framework of a comprehensive quantum-kinetic theory of photovoltaics [6] as applied to ultra-thin absorber architectures [7]. One of the main applications of the photovoltaic reciprocity relation is the determination of quasi-Fermi level splittings (QFLS) in solar cells from the measurement of luminescence. In nanostructure-based photovoltaic architectures, the determination of QFLS is challenging, but instrumental to assess the performance potential of the concepts. Here, we use our quasi-Fermi level-free theory to investigate existence and size of QFLS in quantum well and quantum dot solar cells. [1] Uwe Rau. Reciprocity relation between photovoltaic quantum efficiency and electrolumines- cent emission of solar cells. Phys. Rev. B, 76(8):085303, 2007. [2] Thomas Kirchartz and Uwe Rau. Electroluminescence analysis of high efficiency cu(in,ga)se2 solar cells. J. Appl. Phys., 102(10), 2007. [3] Thomas Kirchartz, Uwe Rau, Martin Hermle, Andreas W. Bett, Anke Helbig, and Jrgen H. Werner. Internal voltages in GaInP-GaInAs-Ge multijunction solar cells determined by electro- luminescence measurements. Appl. Phys. Lett., 92(12), 2008. [4] Thomas Kirchartz, Anke Helbig, Wilfried Reetz, Michael Reuter, Jürgen H. Werner, and Uwe Rau. Reciprocity between electroluminescence and quantum efficiency used for the characterization of silicon solar cells. Prog. Photovolt: Res. Appl., 17(6):394-402, 2009. [5] U. Hoyer, M. Wagner, Th. Swonke, J. Bachmann, R. Auer, A. Osvet, and C. J. Brabec. Electroluminescence imaging of organic photovoltaic modules. Appl. Phys. Lett., 97(23), 2010. [6] U. Aeberhard. Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Greens function formalism. J. Comput. Electron., 10:394-413, 2011. [7] U. Aeberhard. Simulation of ultrathin solar cells beyond the limits of the semiclassical bulk picture. IEEE J. Photovolt., 6(3):654-660, 2016.

Higher-order Fermi-liquid corrections for an Anderson impurity away from half filling : Equilibrium properties

NASA Astrophysics Data System (ADS)

Oguri, Akira; Hewson, A. C.

2018-01-01

We study the low-energy behavior of the vertex function of a single Anderson impurity away from half filling for finite magnetic fields, using the Ward identities with careful consideration of the antisymmetry and analytic properties. The asymptotic form of the vertex function Γσσ';σ'σ(i ω ,i ω';i ω',i ω ) is determined up to terms of linear order with respect to the two frequencies ω and ω', as well as the ω2 contribution for antiparallel spins σ'≠σ at ω'=0 . From these results, we also obtain a series of the Fermi-liquid relations beyond those of Yamada-Yosida [Prog. Theor. Phys. 54, 316 (1975), 10.1143/PTP.54.316]. The ω2 real part of the self-energy Σσ(i ω ) is shown to be expressed in terms of the double derivative ∂2Σσ(0 ) /∂ ɛdσ 2 with respect to the impurity energy level ɛdσ, and agrees with the formula obtained recently by Filippone, Moca, von Delft, and Mora (FMvDM) in the Nozières phenomenological Fermi-liquid theory [Phys. Rev. B 95, 165404 (2017), 10.1103/PhysRevB.95.165404]. We also calculate the T2 correction of the self-energy and find that the real part can be expressed in terms of the three-body correlation function ∂ χ↑↓/∂ ɛd,-σ , where χ↑↓ is the static susceptibility between antiparallel spins. We also provide an alternative derivation of the asymptotic form of the vertex function. Specifically, we calculate the skeleton diagrams for the vertex function Γσσ ;σ σ(i ω ,0 ;0 ,i ω ) for parallel spins up to order U4 in the Coulomb repulsion U . It directly clarifies the fact that the analytic components of order ω vanish as a result of the cancellation of four related Feynman diagrams, which are related to each other through the antisymmetry operation.

The Resilience of Women in Higher Education in Afghanistan. Study No 1: Obstacles and Opportunities in Women's Enrollment and Graduation; Study No. 2: The Human, Social and Institutional Resilience of Female Doctors and Postgraduate Residency Programs. Resilience in Education Settings (RES)-Research Studies Series

ERIC Educational Resources Information Center

Kosha, Afifa; Oriya, Spozhmay; Nabi, Tahira; Halim, Sabera; Hofyani, Sohaila; Liwal, Abida; Safi, Najibullah; Sahak, Mohamad Nadir; Noormal, Bashir

2014-01-01

Female access to higher education in Afghanistan has been and continues to be limited. At the basic education level, the country has made great advances since 2000; it increased access from 900,000 students in 2000, almost all boys, to 6.7 million students in 2009, and girl's enrollment increased from 5,000 under the Taliban to 2.4 million in the…

A Riemann-Hilbert approach to asymptotic questions for orthogonal polynomials

NASA Astrophysics Data System (ADS)

Deift, P.; Kriecherbauer, T.; McLaughlin, K. T.-R.; Venakides, S.; Zhou, X.

2001-08-01

A few years ago the authors introduced a new approach to study asymptotic questions for orthogonal polynomials. In this paper we give an overview of our method and review the results which have been obtained in Deift et al. (Internat. Math. Res. Notices (1997) 759, Comm. Pure Appl. Math. 52 (1999) 1491, 1335), Deift (Orthogonal Polynomials and Random Matrices: A Riemann-Hilbert Approach, Courant Lecture Notes, Vol. 3, New York University, 1999), Kriecherbauer and McLaughlin (Internat. Math. Res. Notices (1999) 299) and Baik et al. (J. Amer. Math. Soc. 12 (1999) 1119). We mainly consider orthogonal polynomials with respect to weights on the real line which are either (1) Freud-type weights d[alpha](x)=e-Q(x) dx (Q polynomial or Q(x)=x[beta], [beta]>0), or (2) varying weights d[alpha]n(x)=e-nV(x) dx (V analytic, limx-->[infinity] V(x)/logx=[infinity]). We obtain Plancherel-Rotach-type asymptotics in the entire complex plane as well as asymptotic formulae with error estimates for the leading coefficients, for the recurrence coefficients, and for the zeros of the orthogonal polynomials. Our proof starts from an observation of Fokas et al. (Comm. Math. Phys. 142 (1991) 313) that the orthogonal polynomials can be determined as solutions of certain matrix valued Riemann-Hilbert problems. We analyze the Riemann-Hilbert problems by a steepest descent type method introduced by Deift and Zhou (Ann. Math. 137 (1993) 295) and further developed in Deift and Zhou (Comm. Pure Appl. Math. 48 (1995) 277) and Deift et al. (Proc. Nat. Acad. Sci. USA 95 (1998) 450). A crucial step in our analysis is the use of the well-known equilibrium measure which describes the asymptotic distribution of the zeros of the orthogonal polynomials.

Test Particle Simulations of Electron Injection by the Bursty Bulk Flows (BBFs) using High Resolution Lyon-Feddor-Mobarry (LFM) Code

NASA Astrophysics Data System (ADS)

Eshetu, W. W.; Lyon, J.; Wiltberger, M. J.; Hudson, M. K.

2017-12-01

Test particle simulations of electron injection by the bursty bulk flows (BBFs) have been done using a test particle tracer code [1], and the output fields of the Lyon-Feddor-Mobarry global magnetohydro- dynamics (MHD) code[2]. The MHD code was run with high resolu- tion (oct resolution), and with specified solar wind conditions so as to reproduce the observed qualitative picture of the BBFs [3]. Test par- ticles were injected so that they interact with earthward propagating BBFs. The result of the simulation shows that electrons are pushed ahead of the BBFs and accelerated into the inner magnetosphere. Once electrons are in the inner magnetosphere they are further energized by drift resonance with the azimuthal electric field. In addition pitch angle scattering of electrons resulting in the violation conservation of the first adiabatic invariant has been observed. The violation of the first adiabatic invariant occurs as electrons cross a weak magnetic field region with a strong gradient of the field perturbed by the BBFs. References 1. Kress, B. T., Hudson,M. K., Looper, M. D. , Albert, J., Lyon, J. G., and Goodrich, C. C. (2007), Global MHD test particle simulations of ¿ 10 MeV radiation belt electrons during storm sudden commencement, J. Geophys. Res., 112, A09215, doi:10.1029/2006JA012218. Lyon,J. G., Fedder, J. A., and Mobarry, C.M., The Lyon- Fedder-Mobarry (LFM) Global MHD Magnetospheric Simulation Code (2004), J. Atm. And Solar-Terrestrial Phys., 66, Issue 15-16, 1333- 1350,doi:10.1016/j.jastp. Wiltberger, Merkin, M., Lyon, J. G., and Ohtani, S. (2015), High-resolution global magnetohydrodynamic simulation of bursty bulk flows, J. Geophys. Res. Space Physics, 120, 45554566, doi:10.1002/2015JA021080.

Natural time analysis and Tsallis non-additive entropy statistical mechanics.

NASA Astrophysics Data System (ADS)

Sarlis, N. V.; Skordas, E. S.; Varotsos, P.

2016-12-01

Upon analyzing the seismic data in natural time and employing a sliding natural time window comprising a number of events that would occur in a few months, it has been recently uncovered[1] that a precursory Seismic Electric Signals activity[2] initiates almost simultaneously with the appearance of a minimum in the fluctuations of the order parameter of seismicity [3]. Such minima have been ascertained [4] during periods of the magnitude time series exhibiting long range correlations [5] a few months before all earthquakes of magnitude 7.6 or larger that occurred in the entire Japanese area from 1 January 1984 to 11 March 2011 (the day of the M9 Tohoku-Oki earthquake). Before and after these minima, characteristic changes of the temporal correlations between earthquake magnitudes are observed which cannot be captured by Tsallis non-additive entropy statistical mechanics in the frame of which it has been suggested that kappa distributions arise [6]. Here, we extend the study concerning the existence of such minima in a large area that includes Aegean Sea and its surrounding area which exhibits in general seismo-tectonics [7] different than that of the entire Japanese area. References P. A. Varotsos et al., Tectonophysics, 589 (2013) 116. P. Varotsos and M. Lazaridou, Tectonophysics 188 (1991) 321. P.A. Varotsos et al., Phys Rev E 72 (2005) 041103. N. V. Sarlis et al., Proc Natl Acad Sci USA 110 (2013) 13734. P. A. Varotsos, N. V. Sarlis, and E. S. Skordas, J Geophys Res Space Physics 119 (2014), 9192, doi: 10.1002/2014JA0205800. G. Livadiotis, and D. J. McComas, J Geophys Res 114 (2009) A11105, doi:10.1029/2009JA014352. S. Uyeda et al., Tectonophysics, 304 (1999) 41.

The Blame Game in the Science Preparation of Future Teachers

NASA Astrophysics Data System (ADS)

Stein, Fredrick

2003-10-01

Who is responsible for the general lack of science preparation in our newly certified K-12 teachers? If it is true that teachers "teach as they were taught," then we must look to the college and university departments. The American Physical Society (APS), in partnership with the American Association of Physics Teachers (AAPT) and the American Institute of Physics (AIP), has initiated PhysTEC in concert with national reports calling for the improvement of K-12 science teaching. PhysTEC aims to help physics and education faculty work together to provide an education for future teachers that emphasizes a student-centered, hands-on, inquiry-based approach to learning science. An update of the first two years of the project will be given. Program components include: (1) A long-term, active collaboration between the physics and education departments; (2) A full-time Teacher-in-Residence (TIR) program that provides for a local K-12 science teacher to become a full-time participant in assisting faculty with both team-teaching and course revisions; (3) The redesign of content and pedagogy of targeted physics and education courses; and (4) The establishment of a Induction and mentoring program novice science teachers. This includes the participation of physics faculty in increasing and improving a wide array of school experiences. http://www.phystec.org/

U.S. - India Collaboration on Air Quality and Climate Research and Education

EPA Science Inventory

With partial support from the U.s. National Science Foundation and U.S. Department of Energy, a workshop held March 14 - 24,2011, in India, brought together experts from the United States and India (among other countries) with a common vision for identifying priority areas of res...

Local Heroes Live!

NASA Astrophysics Data System (ADS)

1999-09-01

Physics teacher Andrew Morrison from High Pavement College in Nottingham has recently been appointed as Schools' officer for particle physics by the Particle Physics and Astronomy Research Council, as part of the Council's Public Understanding of Science programme. As well as his role as an experienced physics teacher, Andrew has acted as marketing manager for his college and chair of the Nottinghamshire section of the Association for Science Education. He will now be working two days each week in his new role with PPARC, acting as a link between the science education and research communities, helping researchers develop ideas for promoting particle physics and leading some specific new projects for the production of schools materials. Andrew can be contacted at High Pavement Sixth Form College, Gainsford Crescent, Nottingham NG5 5HT (tel: 0115 916 6165 or e-mail: morrison@innotts.co.uk). On the other side of the Atlantic, an 18 year-old student at Atlee High School in Mechanicsville, Virginia, USA was the recipient of the `1999 Young Scientist of the Year' award. Jakob Harmon submitted a project on magnetic levitation (maglev) in this extracurricular competition organized by PhysLINK.com, a leading Internet authority on physics and engineering education. The prize was a summer placement at Virginia Polytechnic Institute, Blacksburg, where Jakob continued his education in one of the most active maglev research and development groups in the USA. He also received science books and software as part of the award. The PhysLINK.com award was established to recognize, encourage and foster talented high school students in physics and engineering, with the prize being designed to fit the specific needs and aspirations of each individual winner. Details of next year's competition, along with Jakob's project and more about magnetic levitation can be viewed at www.physlink.com or by contacting Anton Skorucak of PhysLINK.com at 11271 Ventura Blvd #299, Studio City, CA 91606, USA (fax: (1) 818 985 2466, e-mail: info@physlink.com).

The root coverage esthetic score: Intra-examiner reliability among students and faculty at tufts university school of dental medicine.

PubMed

Isaia, Federica; Gyurko, Robert; Roomian, Tamar C; Hawley, Charles E

2018-04-06

The Root Coverage Esthetic Score (RES) was published in 2009 as an esthetic scoring system to measure visible final outcomes of root coverage procedures performed on Miller I and II recession defects. The aim of this study was to evaluate the intra-examiner, intra-group, and inter-examiner reliability of the (Root Coverage Esthetic Score) RES when used among periodontal faculty, post-graduate students in periodontology, and pre-doctoral DMD students when using the RES at Tufts University School of Dental Medicine (TUSDM). Thirty-three participants (12 second year DMD students, 11 periodontal residents, and 10 faculty members) were assembled to evaluate 25 baseline and 6-months post-treatment outcomes of mucogingival surgeries using the RES. Each projection was shown for 30 seconds during which the participants were asked to use the RES scoring system to evaluate the surgical outcomes. The results were then recorded on a standardized worksheet grid. To test intra-examiner reliability, 7 of the 25 projections were shown twice. Intra-examiner reliability and inter-examiner reliability were assessed using intraclass correlation coefficient using a two-way mixed effects model, and stratified by education level. PG residents had the highest tendency to agree with each other with an interclass correlation (ICC) of 0.53 (95%CI 0.36 - 0.74). DMD students had an ICC: 0.51 (95%CI: 0.33 - 0.75), and PG faculty members produced an ICC: 0.41 (95%CI: 0.24 - 0.64). There was no statistically significant difference in ICC among the three groups of participants (Kruskal-Wallis test, P = 0.2440). When the data for each RES element were then combined, the mean ICC for the total interrater agreement for RES was 0.48 (95% CI: 0.32-0.71). This corresponds to an overall moderate agreement among all participants using the RES to evaluate the 25 surgical outcomes. The intra-examiner reliability within each of the three groups was quite high. The highest mean ICC was produced by the PG Faculty (0.908). The mean ICCs for PG residents was 0.867, and the mean ICC for DMD students was 0.855. The Kruskal-Wallis test (p = 0.46) failed to find any statistical difference in intra-examiner reliability between the three groups of participants CONCLUSIONS: The RES is a "moderately" reliable scoring system for mucogingival treatments in a dental school setting and can be used even by operators with different level of periodontal experience. This scoring system can be repeated by the same examiner obtaining reliable results. This article is protected by copyright. All rights reserved. © 2018 American Academy of Periodontology.

Aerosol Processing in Mixed-Phase Clouds in ECHAM5-HAM: Comparison of Single-Column Model Simulations to Observations

NASA Astrophysics Data System (ADS)

Hoose, C.; Lohmann, U.; Stier, P.; Verheggen, B.; Weingartner, E.; Herich, H.

2007-12-01

The global aerosol-climate model ECHAM5-HAM (Stier et al., 2005) has been extended by an explicit treatment of cloud-borne particles. Two additional modes for in-droplet and in-crystal particles are introduced, which are coupled to the number of cloud droplet and ice crystal concentrations simulated by the ECHAM5 double-moment cloud microphysics scheme (Lohmann et al., 2007). Transfer, production and removal of cloud-borne aerosol number and mass by cloud droplet activation, collision scavenging, aqueous-phase sulfate production, freezing, melting, evaporation, sublimation and precipitation formation are taken into account. The model performance is demonstrated and validated with observations of the evolution of total and interstitial aerosol concentrations and size distributions during three different mixed-phase cloud events at the alpine high-altitude research station Jungfraujoch (Switzerland) (Verheggen et al, 2007). Although the single-column simulations can not be compared one-to-one with the observations, the governing processes in the evolution of the cloud and aerosol parameters are captured qualitatively well. High scavenged fractions are found during the presence of liquid water, while the release of particles during the Bergeron-Findeisen process results in low scavenged fractions after cloud glaciation. The observed coexistence of liquid and ice, which might be related to cloud heterogeneity at subgrid scales, can only be simulated in the model when forcing non-equilibrium conditions. References: U. Lohmann et al., Cloud microphysics and aerosol indirect effects in the global climate model ECHAM5-HAM, Atmos. Chem. Phys. 7, 3425-3446 (2007) P. Stier et al., The aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys. 5, 1125-1156 (2005) B. Verheggen et al., Aerosol partitioning between the interstitial and the condensed phase in mixed-phase clouds, Accepted for publication in J. Geophys. Res. (2007)

Theoretical Study of Group 14 M^{+}(^{2}P_{J})-RG Complexes (M^{+} = C^{+}, Si^{+}; RG = he - Ar)

NASA Astrophysics Data System (ADS)

Tuttle, William Duncan; Thorington, Rebecca L.; Wright, Timothy G.; Viehland, Larry A.

2017-06-01

The light group 14 cations are found in a wide variety of environments, with, for example, C^{+} ions thought to play a key role in the chemistry of the interstellar medium, while Si^{+} ions are an important component of the upper atmosphere of the Earth due to their presence in meteoroids. We calculate accurate interatomic potentials for a singly charged carbon cation and a singly charged silicon cation interacting with the rare gas atoms helium, neon and argon. The RCCSD(T) method is employed, with basis sets of quadruple-ζ and quintuple-ζ quality, and the energies counterpoise corrected and extrapolated to the basis set limit at each point. In all cases, we consider the lowest electronic states of the M^{+} atom, (^{2}P_{J}), interacting with the ground electronic state of the RG atom, (^{1}S_{0}), and compute potentials corresponding to the molecular terms, ^{2}Π and ^{2}Σ^{+}, as well as the spin-orbit levels which arise: ^{2}Π_{3/2}, ^{2}Π_{1/2} and ^{2}Σ_{1/2}^{+}. The potentials are employed to calculated spectroscopic constants and ion transport properties. S. Petrie and D. K. Bohme, Mass Spec. Rev., 26, 258 (2007). J. M. C. Plane, J. C. Gómez-Martin, W. Feng, and D. Janches, J. Geophys. Res. Atmos. 121, 3718 (2016). W. D. Tuttle, R. L. Thorington, L. A. Viehland and T. G. Wright, Mol. Phys. 113, 3767 (2015). W. D. Tuttle, R. L. Thorington, L. A. Viehland and T. G. Wright (in preparation). W. D. Tuttle, R. L. Thorington, L. A. Viehland and T. G. Wright, Mol. Phys. 115, 437 (2017).

Perturbation of a planetary orbit by the Lambda-term (dark energy) in Einstein equations

NASA Astrophysics Data System (ADS)

Dumin, Yurii

The problem of cosmological influences at small (e.g. interplanetary) scales is discussed for a few decades, starting from the early 1930's, but still remains unsolved definitively by now [1]. This subject became especially topical in the context of the dark-energy-dominated cosmology, because the commonly-used arguments against the local Hubble expansion (such as Einstein-Straus theorem [2]) are inapplicable when the most contribution to the energy density of the Universe comes from the perfectly-uniform dark energy (Lambda-term). Moreover, there are some empirical evidences in favor of the local cosmological influences. For example, inclusion of the local Hubble expansion into dynamics of the Earth-Moon system enables us to resolve a long-standing discrepancy in the rates of secular increase of the lunar semi-major axis (a) mea-sured by the lunar laser ranging and (b) derived from the astrometric observations of the Earth's rotation deceleration [3, 4]. The aim of the present report is to provide a detailed mathematical treatment of the respective two-body problem in the framework of General Relativity, which is based on the Kottler metric reduced to the Robertson-Walker cosmological asymptotics, as outlined in our earlier work [5]. References: 1. W.B. Bonnor. Gen. Rel. Grav., v.32, p.1005 (2000). 2. A. Einstein and E.G. Straus. Rev. Mod. Phys., v.17, p.120 (1945). 3. Yu.V. Dumin. Adv. Space Res., v.31, p.2461 (2003). 4. Yu.V. Dumin. In Proc. 11th Marcel Grossmann Meeting on General Relativity, World Sci., Singapore, p.1752 (2008). 5. Yu.V. Dumin. Phys. Rev. Lett., v.98, p.059001 (2007).

Quantum many-body effects in x-ray spectra efficiently computed using a basic graph algorithm

NASA Astrophysics Data System (ADS)

Liang, Yufeng; Prendergast, David

2018-05-01

The growing interest in using x-ray spectroscopy for refined materials characterization calls for an accurate electronic-structure theory to interpret the x-ray near-edge fine structure. In this work, we propose an efficient and unified framework to describe all the many-electron processes in a Fermi liquid after a sudden perturbation (such as a core hole). This problem has been visited by the Mahan-Noziéres-De Dominicis (MND) theory, but it is intractable to implement various Feynman diagrams within first-principles calculations. Here, we adopt a nondiagrammatic approach and treat all the many-electron processes in the MND theory on an equal footing. Starting from a recently introduced determinant formalism [Phys. Rev. Lett. 118, 096402 (2017), 10.1103/PhysRevLett.118.096402], we exploit the linear dependence of determinants describing different final states involved in the spectral calculations. An elementary graph algorithm, breadth-first search, can be used to quickly identify the important determinants for shaping the spectrum, which avoids the need to evaluate a great number of vanishingly small terms. This search algorithm is performed over the tree-structure of the many-body expansion, which mimics a path-finding process. We demonstrate that the determinantal approach is computationally inexpensive even for obtaining x-ray spectra of extended systems. Using Kohn-Sham orbitals from two self-consistent fields (ground and core-excited state) as input for constructing the determinants, the calculated x-ray spectra for a number of transition metal oxides are in good agreement with experiments. Many-electron aspects beyond the Bethe-Salpeter equation, as captured by this approach, are also discussed, such as shakeup excitations and many-body wave function overlap considered in Anderson's orthogonality catastrophe.

Spatial and Time Dynamics of Non-Linear Vortices in Plasma Lens for High-Current Ion Beam Focusing

NASA Astrophysics Data System (ADS)

Goncharov, Alexei A.; Maslov, Vasyl I.; Onishchenko, Ivan N.; Tretyakov, Vitalij N.

2002-11-01

It is known from numerical simulation (see, for example, [1]) and from experiments (see, for example, [2]), that an electron density bunches as discrete vortices are long - living structures in vacuum. However, in laboratory experiments [2] it has been shown that the vortices are changed faster, when they are submersed in electrons, distributed around them. The charged plasma lens intended for a focussing of high-current ion beams, has the same crossed configuration of a radial electrical and longitudinal magnetic field [3], as only electron plasma. In this lens the vortical turbulence is excited [3]. The vortex - bunch and vortex - hole are rotated in the inverse directions in system of their rest. The instability development in initially homogeneous plasma causes that the vortices are excited by pairs. Namely, if the vortex - bunch of electrons is generated, near the vortex - hole of electrons is also generated. It is shown, that in nonuniform plasma the vortices behave is various in time. Namely, the vortex - bunch goes to area of larger electron density, and the vortex - hole goes to area of smaller electron density. The speed of the vortex - hole is less than speed of the vortex - bunch. It is shown, that the electron vortices, generated in the plasma lens, can result in to formation of spiral distribution of electron density. The physical mechanism of coalescence of electron vortices - bunches is proposed. 1.Driscoll C.F. et al. Plasma Phys. Contr. Fus. Res. 3 (1989) 507. 2.Kiwamoto Y. et al. Non-neutral plasma physics. Princeton. 1999. P. 99-105. 3.Goncharov A. et al. Plasma Phys. Rep. 20 (1994) 499.

First principles study of iron-bearing MgO under ultrahigh pressure

NASA Astrophysics Data System (ADS)

Umemoto, K.; Hsu, H.

2017-12-01

Understanding of minerals under ultrahigh pressure is essential to model interiors of super-Earths. Chemical compositions of the super-Earths are expected to be similar to those of the Earth. Computational studies on Mg-Si-O ternary systems under ultrahigh pressures, which are difficult to be achieved by diamond-anvil-cell experiments, have been intensively performed (e.g., [1] for MgO, [2,3] for SiO2, and [4,5] for MgSiO3). However, as far as we know, these studies have been restricted to pure Mg-Si-O systems. In the mantles of super-Earths, we expect that there should be impurities as in the Earth's mantle. Among candidates of impurities, iron is especially important to model interiors of super-Earths. Here, we investigate iron-bearing MgO under ultrahigh pressures by first principles. We clarify effects of iron on the phase transition of MgO and thermodynamic quantities by first principles. The role of the 3d electrons will be elucidated. [1] Z. Wu, R. M. Wentzcovitch, K. Umemoto, B. Li, K. Hirose, and J. C. Zheng, J. Geophys. Res. 113, B06204 (2008). [2] S. Q. Wu, K. Umemoto, M. Ji, C. Z. Wang, K. M. Ho, and R. M. Wentzcovitch, Phys. Rev. B 83, 184102 (2011). [3] T. Tsuchiya and J. Tsuchiya, Proc. Nat. Acad. Sci. 108, 1252 (2011) [4] S. Q. Wu, M. Ji, C. Z. Wang, M. C. Nguye, X. Zhao, K. Umemoto, R. M. Wentzcovitch, and K. M. Ho, J. Phys.: Condens. Matter 26, 035402 (2014). [5] H. Niu, A. R. Oganov, X.-C. Chen, and D. Li, Sci. Rep. 5, 18347 (2015).

Impact of Aerosol Processing on Orographic Clouds

NASA Astrophysics Data System (ADS)

Pousse-Nottelmann, Sara; Zubler, Elias M.; Lohmann, Ulrike

2010-05-01

Aerosol particles undergo significant modifications during their residence time in the atmosphere. Physical processes like coagulation, coating and water uptake, and aqueous surface chemistry alter the aerosol size distribution and composition. At this, clouds play a primary role as physical and chemical processing inside cloud droplets contributes considerably to the changes in aerosol particles. A previous study estimates that on global average atmospheric particles are cycled three times through a cloud before being removed from the atmosphere [1]. An explicit and detailed treatment of cloud-borne particles has been implemented in the regional weather forecast and climate model COSMO-CLM. The employed model version includes a two-moment cloud microphysical scheme [2] that has been coupled to the aerosol microphysical scheme M7 [3] as described by Muhlbauer and Lohmann, 2008 [4]. So far, the formation, transfer and removal of cloud-borne aerosol number and mass were not considered in the model. Following the parameterization for cloud-borne particles developed by Hoose et al., 2008 [5], distinction between in-droplet and in-crystal particles is made to more physically account for processes in mixed-phase clouds, such as the Wegener-Bergeron-Findeisen process and contact and immersion freezing. In our model, this approach has been extended to allow for aerosol particles in five different hydrometeors: cloud droplets, rain drops, ice crystals, snow flakes and graupel. We account for nucleation scavenging, freezing and melting processes, autoconversion, accretion, aggregation, riming and selfcollection, collisions between interstitial aerosol particles and hydrometeors, ice multiplication, sedimentation, evaporation and sublimation. The new scheme allows an evaluation of the cloud cycling of aerosol particles by tracking the particles even when scavenged into hydrometeors. Global simulations of aerosol processing in clouds have recently been conducted by Hoose et al. [6]. Our investigation regarding the influence of aerosol processing will focus on the regional scale using a cloud-system resolving model with a much higher resolution. Emphasis will be placed on orographic mixed-phase precipitation. Different two-dimensional simulations of idealized orographic clouds will be conducted to estimate the effect of aerosol processing on orographic cloud formation and precipitation. Here, cloud lifetime, location and extent as well as the cloud type will be of particular interest. In a supplementary study, the new parameterization will be compared to observations of total and interstitial aerosol concentrations and size distribution at the remote high alpine research station Jungfraujoch in Switzerland. In addition, our simulations will be compared to recent simulations of aerosol processing in warm, mixed-phase and cold clouds, which have been carried out at the location of Jungfraujoch station [5]. References: [1] Pruppacher & Jaenicke (1995), The processing of water vapor and aerosols by atmospheric clouds, a global estimate, Atmos. Res., 38, 283295. [2] Seifert & Beheng (2006), A two-moment microphysics parameterization for mixed-phase clouds. Part 1: Model description, Meteorol. Atmos. Phys., 92, 4566. [3] Vignati et al. (2004), An efficient size-resolved aerosol microphysics module for large-scale transport models, J. Geophys. Res., 109, D22202 [4] Muhlbauer & Lohmann (2008), Sensitivity studies of the role of aerosols in warm-phase orographic precipitation in different flow regimes, J. Atmos. Sci., 65, 25222542. [5] Hoose et al. (2008), Aerosol processing in mixed-phase clouds in ECHAM5HAM: Model description and comparison to observations, J. Geophys. Res., 113, D071210. [6] Hoose et al. (2008), Global simulations of aerosol processing in clouds, Atmos. Chem. Phys., 8, 69396963.

Monitoring of Student Right To Know and Campus Security Act of 1990. Report To Accompany H. Res. 470. House of Representatives, 104th Congress, 2d Session.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. House Committee on Economic and Educational Opportunities.

This report to accompany House Resolution 470 expresses the sense of Congress that the Department of Education should play a more active role in the monitoring of and enforcing compliance with the Higher Education Act of 1965 related to campus crime. The report makes reference to the Campus Crime and Security Awareness Act, enacted as part of the…

Investigation of a Particle into Liquid Sampler to Study the Formation & Ageing of Secondary Organic Aerosol

NASA Astrophysics Data System (ADS)

Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Munoz, A.; Vazquez, M.; Rodenas, M.; Vera, T.; Borrás, E.

2012-12-01

The atmospheric oxidation of Volatile Organic Compounds (VOCs) in the presence of NOx results in the formation of tropospheric ozone and Secondary Organic Aerosol (SOA) [Hallquist et al., 2009]. Whilst SOA is known to affect both climate and human health, the VOC oxidation pathways leading to SOA formation are poorly understood [Solomon et al., 2007]. This is in part due to the vast number and the low concentration of SOA species present in the ambient atmosphere. It has been estimated as many as 10,000 to 100,000 VOCs have been detected in the atmosphere, all of which can undergo photo-chemical oxidation and contribute to SOA formation [Goldstein and Galbally, 2007]. Atmospheric simulation chambers such as the EUropean PHOtoREactor (EUPHORE) in Valencia, Spain, are often used to study SOA formation from a single VOC precursor under controlled conditions. SOA composition and formation can be studied using online techniques such as Aerosol Mass Spectrometry (AMS), which provide high time resolution but limited structural information [Zhang et al., 2007]. Offline techniques, such as collection onto filters, extraction and subsequent analysis, provide detailed SOA composition but only usually one or two samples per experiment. In this work we report time resolved SOA composition analysis using a Particle into Liquid Sampler (PILS) followed by Liquid Chromatography Ion-Trap Mass Spectrometry (LC-IT-MS/MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS/MS). Experiments were performed at EUPHORE investigating the formation and composition of Methyl Chavicol SOA. Methyl Chavicol (also known as Estragole) was identified as the highest floral emission from an oil palm plantation in Malaysian Borneo and has also been observed in US pine forests [Bouvier-Brown et al., 2009; Misztal et al., 2010]. Previous studies indicate a high SOA yield from Methyl Chavicol at around 40 % [Lee et al., 2006], however currently there have been very few literature reports of the atmospheric degradation of Methyl Chavicol. Methyl Chavicol oxidation was investigated using a series of photosmog and ozonolysis experiments with varying ratios of NOx:VOC. An extensive range of instruments were used to monitor radical and product formation [including: LIF (HOx intermediates), LOPAP (HONO), FT-IR, PTR-MS, GC-FID, and SMPS]. Samples were collected using the PILS at 30 minute intervals with filters taken at the end of each experiment for comparison. A number of key oxidation products have been identified. Time profiles can be used to determine the importance of first, second & higher oxidation products and may indicate which species are undergoing oxidation or heterogeneous reactions during aerosol ageing. This data will allow for modelled vs. measured SOA composition comparison, with the potential to determine the rates of reactions for the condensed phase oxidation products formed. References Bouvier-Brown et al., Atmos. Chem. Phys. 9, 2061-2074, 2009. Goldstein and Galbally, Environ. Sci. Technol. 41, 1514-1521, 2007. Hallquist et al., Atmos. Chem. Phys. 9, 5155-5236, 2009. Lee et al., J. Geophys. Res. 111, D17305, 2006. Misztal et al., Atmos. Chem. Phys. Discuss. 10, 1517-1557, 2010. Solomon et al., Climate Change 2007: IPCC Report. Cambridge, 2007. Zhang et al., Geophys. Res. Lett. 34, L13801, 2007.

Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons

NASA Astrophysics Data System (ADS)

Makarova, Anastasia; Gottschalk, Bernard; Sauerwein, Wolfgang

2017-08-01

Usually, Monte Carlo models are validated against experimental data. However, models of multiple Coulomb scattering (MCS) in the Gaussian approximation are exceptional in that we have theories which are probably more accurate than the experiments which have, so far, been done to test them. In problems directly sensitive to the distribution of angles leaving the target, the relevant theory is the Molière/Fano/Hanson variant of Molière theory (Gottschalk et al 1993 Nucl. Instrum. Methods Phys. Res. B 74 467-90). For transverse spreading of the beam in the target itself, the theory of Preston and Koehler (Gottschalk (2012 arXiv:1204.4470)) holds. Therefore, in this paper we compare Geant4 simulations, using the Urban and Wentzel models of MCS, with theory rather than experiment, revealing trends which would otherwise be obscured by experimental scatter. For medium-energy (radiotherapy) protons, and low-Z (water-like) target materials, Wentzel appears to be better than Urban in simulating the distribution of outgoing angles. For beam spreading in the target itself, the two models are essentially equal.

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

DOE PAGES

Yamada, Masaaki

2016-01-01

This study briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactormore » program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.« less

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

NASA Astrophysics Data System (ADS)

Yamada, Masaaki

2016-03-01

This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactor program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

NASA Astrophysics Data System (ADS)

Lai, Xiaochun; Meng, Ling-Jian

2018-02-01

In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147-51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Masaaki

2016-03-25

This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactormore » program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.« less

Determination by Small-angle X-ray Scattering of Pore Size Distribution in Nanoporous Track-etched Polycarbonate Membranes

NASA Astrophysics Data System (ADS)

Jonas, A. M.; Legras, R.; Ferain, E.

1998-03-01

Nanoporous track-etched membranes with narrow pore size distributions and average pore size diameters tunable from 100 to 1000 Åare produced by the chemical etching of latent tracks in polymer films after irradiation by a beam of accelerated heavy ions. Nanoporous membranes are used for highly demanding filtration purposes, or as templates to obtain metallic or polymeric nanowires (L. Piraux et al., Nucl. Instr. Meth. Phys. Res. 1997, B131, 357). Such applications call for developments in nanopore size characterization techniques. In this respect, we report on the characterization by small-angle X-ray scattering (SAXS) of nanopore size distribution (nPSD) in polycarbonate track-etched membranes. The obtention of nPSD requires inverting an ill-conditioned inhomogeneous equation. We present different numerical routes to overcome the amplification of experimental errors in the resulting solutions, including a regularization technique allowing to obtain the nPSD without a priori knowledge of its shape. The effect of deviations from cylindrical pore shape on the resulting distributions are analyzed. Finally, SAXS results are compared to results obtained by electron microscopy and conductometry.

Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons.

PubMed

Makarova, Anastasia; Gottschalk, Bernard; Sauerwein, Wolfgang

2017-07-06

Usually, Monte Carlo models are validated against experimental data. However, models of multiple Coulomb scattering (MCS) in the Gaussian approximation are exceptional in that we have theories which are probably more accurate than the experiments which have, so far, been done to test them. In problems directly sensitive to the distribution of angles leaving the target, the relevant theory is the Molière/Fano/Hanson variant of Molière theory (Gottschalk et al 1993 Nucl. Instrum. Methods Phys. Res. B 74 467-90). For transverse spreading of the beam in the target itself, the theory of Preston and Koehler (Gottschalk (2012 arXiv:1204.4470)) holds. Therefore, in this paper we compare Geant4 simulations, using the Urban and Wentzel models of MCS, with theory rather than experiment, revealing trends which would otherwise be obscured by experimental scatter. For medium-energy (radiotherapy) protons, and low-Z (water-like) target materials, Wentzel appears to be better than Urban in simulating the distribution of outgoing angles. For beam spreading in the target itself, the two models are essentially equal.

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Enhancing Technical Skill Learning through Interleaved Mixed-Model Observational Practice

ERIC Educational Resources Information Center

Welsher, Arthur; Grierson, Lawrence E. M.

2017-01-01

A broad foundation of behavioural (Hayes et al. in "Exp Brain Res" 204(2): 199-206, 2010) and neurophysiological (Kohler et al. in "Science" 297(5582): 846-848, 2002) evidence has revealed that the acquisition of psychomotor skills, including those germane to clinical practice (Domuracki et al. in "Med Educ" 49(2):…

"On the Nature of Institutional Research" Revisited: "Plus ca Change..."?

ERIC Educational Resources Information Center

Terenzini, Patrick T.

2013-01-01

In reconsidering the three "tiers of institutional intelligence" needed for effective institutional research practice he first offered 20 years ago (Terenzini in "Res Higher Educ" 34:1-10, 1993), Terenzini suggests that those forms of intelligence retain their overall relevance today, but that they also require some important redefinition. The…

Mapping cognitive structures of community college students engaged in basic electrostatics laboratories

NASA Astrophysics Data System (ADS)

Haggerty, Dennis Charles

Community college students need to be abstract thinkers in order to be successful in the introductory Physics curriculum. The purpose of this dissertation is to map the abstract thinking of community college Physics students. The laboratory environment was used as a vehicle for the mapping. Three laboratory experiments were encountered. One laboratory was based on the classic Piagetian task, the centripetal motion (CM) problem. The other two laboratories were introductory electrostatic Physics experiments, Resistance (RES) and Capacitance (CAP). The students performed all laboratories using the thinking-aloud technique. The researcher collected their verbal protocols using audiotapes. The audiotaped data was quantified by comparing it to a scoring matrix based on the Piagetian logical operators (Inhelder & Piaget, 1958) for abstract thinking. The students received scores for each laboratory experiment. These scores were compared to a reliable test of intellectual functioning, the Shipley Institute of Living Scale (SILS). Spearman rank correlation coefficients (SRCC) were obtained for SILS versus CM; SILS versus RES; and SILS versus CAP. Statistically significant results were obtained for SILS versus CM and SILS versus RES at the p < 0.05 level. When an outlier to the data was considered and suppressed, the SILS versus CAP was also statistically significant at the p < 0.05 level. The scoring matrix permits a bridge from the qualitative Piagetian level of cognitive development to a quantified, mapped level of cognitive development. The ability to quantify student abstract thinking in Physics education provides a means to adjust an instructional approach. This approach could lead to a proper state of Physics education.

Resolution Urging Continuation of Federal Involvement in Child Nutrition Programs. Hearings on H. Con. Res. 384 Before the Subcommittee on Elementary, Secondary, and Vocational Education of the Committee on Education and Labor. House of Representatives, Ninety-Seventh Congress, Second Session (September 21, 22, 1982).

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. House Committee on Education and Labor.

This report presents the transcript of Congressional committee hearings on a resolution urging continuation of Federal support for child nutrition programs, in view of proposals by the Reagan administration to turn responsibility for such programs over to the States. The report includes texts of statements, letters, and supplemental materials…

Magnetic Reconnection Controls Impacts of Solar Wind Ions at Mercury's Surface : Investigation By Global Hybrid Simulations

NASA Astrophysics Data System (ADS)

Chanteur, G. M.; Modolo, R.; Leblanc, F.

2014-12-01

MESSENGER has revealed the complexity of the Hermean magnetic field which is dominated by dipolar and quadrupolar components (Anderson et al., 2012 and references therein). By contrast to other magnetized planets having large scale dynamo driven magnetic fields Mercury has a quadrupolar field large enough to reinforce the dipolar field at high northern latitudes and to shape the topology of the planetary field in the equatorial region and the southern hemisphere. Magnetic reconnection at Mercury is extremely effective for all IMF orientations [DiBraccio et al., JGR, 2013]. Global hybrid simulations by Richer et al. (2012) have demonstrated the dramatic influence of the quadrupolar field of Mercury on the topology of the Hermean magnetosphere. Then Chanteur et al. (AOGS 2014) have investigated the impacts of solar wind protons and alphas on Mercury's surface with the same hybrid code and have presented a case study to demonstrate the importance of magnetic reconnection between the IMF and the planetary field in this process. We will present a set of different results corresponding to different configurations depending upon the IMF orientation and solar wind parameters. References Anderson, B. J., C. L. Johnson, H. Korth, R. M. Winslow, J. E. Borovsky, M. E. Purucker, J. A. Slavin, S. C. Solomon, M. T. Zuber, and R. L. McNutt Jr. (2012), Low-degree structure in Mercury's planetary magnetic field, J. Geophys. Res., 117, E00L12, doi:10.1029/2012JE004159. DiBraccio, G. A., J. A. Slavin, S. A. Boardsen, B. J. Anderson, H. Korth, T. H. Zurbuchen, J. M. Raines, D. N. Baker, R. L. McNutt Jr., and S. C. Solomon (2013), MESSENGER observations of magnetopause structure and dynamics at Mercury, J. Geophys. Res. Space Phys., 118, 997-1008, doi:10.1002/jgra50123. Richer, E., R. Modolo, G. M. Chanteur, S. Hess, and F. Leblanc (2012), A global hybrid model for Mercury's interaction with the solar wind: Case study of the dipole representation, J. Geophys. Res., 117, A10228, doi:10.1029/2012JA017898. Chanteur, G.M., R. Modolo, and F. Leblanc (2014), Effect of the Hermean Magnetic quadrupole on Magnetic Reconnection and Penetration of the SW Plasma Inside the Magnetosphere, AOGS, 11th annual meeting, Sapporo, Japan, July 28th - August 1st.

Is there a self-organization principle of river deltas?

NASA Astrophysics Data System (ADS)

Tejedor, Alejandro; Longjas, Anthony; Foufoula-Georgiou, Efi

2017-04-01

River deltas are known to possess a complex topological and flux-partitioning structure which has recently been quantified using spectral graph theory [Tejedor et al., 2015a,b]. By analysis of real and simulated deltas it has also been shown that there is promise in formalizing relationships between this topo-dynamic delta structure and the underlying delta forming processes [e.g., Tejedor et al., 2016]. The question we pose here is whether there exists a first order organizational principle behind the self-organization of river deltas and whether this principle can be unraveled from the co-evolving topo-dynamic structure encoded in the delta planform. To answer this question, we introduce a new metric, the nonlocal Entropy Rate (nER) that captures the information content of a delta network in terms of the degree of uncertainty in delivering fluxes from any point of the network to the shoreline. We hypothesize that if the "guiding principle" of undisturbed deltas is to efficiently and robustly build land by increasing the diversity of their flux pathways over the delta plane, then they would exhibit maximum nonlocal Entropy Rate at states at which geometry and flux dynamics are at equilibrium. At the same time, their nER would be non-optimal at transient states, such as before and after major avulsions during which topology and dynamics adjust to each other to reach a new equilibrium state. We will present our results for field and simulated deltas, which confirm this hypothesis and open up new ways of thinking about self-organization, complexity and robustness in river deltas. One particular connection of interest might have important implications since entropy rate and resilience are related by the fluctuation theorem [Demetrius and Manke, 2005], and therefore our results suggest that deltas might in fact self-organize to maximize their resilience to structural and dynamic perturbations. References: Tejedor, A., A. Longjas, I. Zaliapin, and E. Foufoula­-Georgiou (2015), Water Resour. Res., 51, 3998-4018. Tejedor, A., A. Longjas, I. Zaliapin, and E. Foufoula-­Georgiou (2015), Water Resour. Res., 51, 4019-4045. Tejedor, A., A. Longjas, R. Caldwell, D. A. Edmonds, I. Zaliapin, and E. Foufoula­-Georgiou (2016), Geophys. Res. Lett., 43, 3280-3287. Demetrius, L., and T. Manke (2005), Phys. A Stat. Mech. Appl., 346, 682-696.

Simple Numerical Analysis of Longboard Speedometer Data

ERIC Educational Resources Information Center

Hare, Jonathan

2013-01-01

Simple numerical data analysis is described, using a standard spreadsheet program, to determine distance, velocity (speed) and acceleration from voltage data generated by a skateboard/longboard speedometer (Hare 2012 "Phys. Educ." 47 409-17). This simple analysis is an introduction to data processing including scaling data as well as…

Producing Liquid Oxygen in the Classroom

ERIC Educational Resources Information Center

Williams, David; Warden, Nicole; Wharton, Barry

2016-01-01

A number of organisations have provided instructions on how to produce small quantities of liquid oxygen in the classroom using liquid nitrogen and a copper condensation coil (Lister 1995 "Classic Chemistry Demonstrations" (London: Royal Society of Chemistry) pp 61-2, French and Hibbert 2010 "Phys. Educ." 45 221-2). The method…

The immersion freezing behavior of mixtures of mineral dust and biological substances

NASA Astrophysics Data System (ADS)

Augustin, Stefanie; Schneider, Johannes; Schmidt, Susan; Niedermeier, Dennis; Ebert, Martin; Voigtländer, Jens; Rösch, Michael; Stratmann, Frank; Wex, Heike

2014-05-01

Biological particles such as bacteria or pollen are known to be efficient ice nuclei. It is also known that ice nucleating active (INA) macromolecules, i.e. protein complexes in the case of bacteria (e.g. Wolber et al., 1986), and most likely polysaccharides in the case of pollen (Pummer et al., 2012) are responsible for the freezing. Very recently it was suggested that these INA macromolecules maintain their nucleating ability even when they are separated from their original carriers (Hartmann et al., 2013; Augustin et al., 2013). This opens the possibility of accumulation of such INA macromolecules in e.g. soils and the resulting particles could be an internal mixture of mineral dust and INA macromolecules. If such biological IN containing soil particles are then dispersed into the atmosphere due to e.g. wind erosion or agricultural processes they could induce ice nucleation at temperatures higher than -20°C. To explore this hypothesis, we performed a measurement campaign within the research unit INUIT, where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INA macromolecules. Specifically, we mixed pure mineral dust (illite) with INA biological material (SNOMAX and birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). To characterize the mixing state of the produced aerosol we used single mass spectrometry as well as electron microscopy. We found that internally mixed particles which containing ice active biological material show the same ice nucleation behavior as the purely biological particles. That shows that INA macromolecules which are located on a mineral dust particle dominate the freezing process. Acknowledgement: Part of this work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525) under WE 4722/1-1. Augustin, S., Hartmann, S., Pummer, B., Grothe, H., Niedermeier, D., Clauss, T., Voigtländer, J., Tomsche, L, Wex, H. and Stratmann, F., Atmos. Chem. Phys. Discuss., 13, 10989-11003, 2013. Hartmann, S., Augustin, S.,D. Niedermeier, J. Voigtlander, T. Clauss, H. Wex, and F. Stratmann, Atmos. Chem. Physics , 13, 5751-5766, 2013. Hoose, C., Kristjansson, J. E., Burrows, S. M., Environ. Res. Lett. 5, 024009, 2010. Kanitz, T., Seifert, P., Ansmann, A., Engelmann, R., Althausen, D., Casiccia, C., and Rohwer, E. G., Geophys. Res. Lett., 38, L17802, 2011. Murray, B. J., OSullivan, D., Atkinson, J. D. and Webb, M. E., Chem. Soc. Rev., 41, 6519-6554, 2012. Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S. and Grothe, H, Atmos. Chem. Phys., 12, 2541-2550, 2012. Wolber, P. K., Deininger, C. A., Southworth, M. W., Vandekerckhove, J., Vanmontagu, M. and Warren, G. J, Proc. Natl. Acad. Sci. USA, 83, 7256- 7260, 1986

Numerically derived parametrisation of optimal RMP coil phase as a guide to experiments on ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Ryan, D. A.; Liu, Y. Q.; Li, L.; Kirk, A.; Dunne, M.; Dudson, B.; Piovesan, P.; Suttrop, W.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

2017-02-01

Edge localised modes (ELMs) are a repetitive MHD instability, which may be mitigated or suppressed by the application of resonant magnetic perturbations (RMPs). In tokamaks which have an upper and lower set of RMP coils, the applied spectrum of the RMPs can be tuned for optimal ELM control, by introducing a toroidal phase difference {{Δ }}{{Φ }} between the upper and lower rows. The magnitude of the outermost resonant component of the RMP field | {b}{{res}}1| (other proposed criteria are discussed herein) has been shown experimentally to correlate with mitigated ELM frequency, and to be controllable by {{Δ }}{{Φ }} (Kirk et al 2013 Plasma Phys. Control. Fusion 53 043007). This suggests that ELM mitigation may be optimised by choosing {{Δ }}{{Φ }}={{Δ }}{{{Φ }}}{{opt}}, such that | {b}{{res}}1| is maximised. However it is currently impractical to compute {{Δ }}{{{Φ }}}{{opt}} in advance of experiments. This motivates this computational study of the dependence of the optimal coil phase difference {{Δ }}{{{Φ }}}{{opt}}, on global plasma parameters {β }N and q 95, in order to produce a simple parametrisation of {{Δ }}{{{Φ }}}{{opt}}. In this work, a set of tokamak equilibria spanning a wide range of ({β }N, q 95) is produced, based on a reference equilibrium from an ASDEX Upgrade experiment. The MARS-F code (Liu et al 2000 Phys. Plasmas 7 3681) is then used to compute {{Δ }}{{{Φ }}}{{opt}} across this equilibrium set for toroidal mode numbers n = 1-4, both for the vacuum field and including the plasma response. The computational scan finds that for fixed plasma boundary shape, rotation profiles and toroidal mode number n, {{Δ }}{{{Φ }}}{{opt}} is a smoothly varying function of ({β }N, q 95). A 2D quadratic function in ({β }N, q 95) is used to parametrise {{Δ }}{{{Φ }}}{{opt}}, such that for given ({β }N, q 95) and n, an estimate of {{Δ }}{{{Φ }}}{{opt}} may be made without requiring a plasma response computation. To quantify the uncertainty of the parametrisation relative to a plasma response computation, {{Δ }}{{{Φ }}}{{opt}} is also computed using MARS-F for a set of benchmarking points. Each benchmarking point consists of a distinct free boundary equilibrium reconstructed from an ASDEX Upgrade RMP experiment, and set of experimental kinetic profiles and coil currents. Comparing the MARS-F predictions of {{Δ }}{{{Φ }}}{{opt}} for these benchmarking points to predictions of the 2D quadratic, shows that relative to a plasma response computation with MARS-F the 2D quadratic is accurate to 26.5° for n = 1, and 20.6° for n = 2. Potential sources for uncertainty are assessed.

Arctic chlorine activation and ozone depletion: Comparison of chemistry transport models with satellite observations.

NASA Astrophysics Data System (ADS)

Grooß, J.-U.; Wegner, T.; Müller, R.; Chipperfield, M. P.; Feng, W.; Santee, M. L.

2009-04-01

The accurate simulation of Arctic stratospheric ozone depletion has been an issue for two decades. However, there are still notable quantitative discrepancies between the models and observations. We show results from the SLIMCAT and CLaMS 3D chemistry-transport models that differ in some aspects of simulated chlorine activation and descent in the polar vortex. Consequently, the estimates of accumulated ozone depletion in the polar vortex for these two models in cold Arctic winters still largely disagree. As shown recently by Santee et al. (JGR, 2008) using MLS and ACE data, the extent of chlorine activation for the cold Arctic winter of 2004/2005 within the basic SLIMCAT model is overestimated with the likely consequence of too much simulated ozone depletion. In contrast, the CLaMS simulation for the same winter shows too little chlorine activation compared to observations, and therefore likely too little loss. For SLIMCAT the version used by Santee et al. has been updated to replace the equilibrium treatment of NAT PSCs with a Lagrangian microphysical scheme. This leads to smaller regions of NAT particles and less denitrification, in better agreement with observations. The impact of this on the modeled extent of chlorine activation will be discussed. For CLaMS we have changed the parameterization of heterogeneous reactions on liquid aerosols from Carslaw et al. to that of Shi et al. (2001), with which chlorine activation on liquid aerosol becomes more efficient. In turn, the simulated chlorine activation agrees better with the observations. The impact of these model changes on chlorine activation and ozone loss will be assessed and remaining model-observation discrepancies will be discussed in terms of different model formulations. We will also show the impact of recent lab measurements of Cl2O2 absorption cross sections by von Hobe et al. (2009) on the simulated ozone depletion. References: von Hobe, M., F. Stroh, H. Beckers, T. Benter, and H. Willner, The UV/Vis absorption spectrum of matrix isolated dichlorine peroxide, ClOOCl, Phys. Chem. Chem. Phys. , doi:10.1039/B814373K, 2009. Santee M. L., I. A. MacKenzie, G. L. Manney, M. P. Chipperfield, P. F. Bernath, K. A. Walker, C. D. Boone, L. Froidevaux, N. J. Livesey, J. W. Waters, A study of stratospheric chlorine partitioning based on new satellite measurements and modeling, J. Geophys. Res., 113, D12307, doi:10.1029/2007JD009057, 2008. Shi, Q., J. Jayne, C. Kolb, D. Worsnop, and P. Davidovits, Kinetic model for reaction of ClONO2 with H2O and HCl and HOCl with HCl in sulfuric acid solutions, J. Geophys. Res., 106, 24259-24274, 2001.

Generation of ion temperature anisotropy in kinetic hybrid-Vlasov simulations (Invited)

NASA Astrophysics Data System (ADS)

Perrone, D.; Valentini, F.; Servidio, S.; Dalena, S.; Veltri, P.

2013-12-01

The interplanetary medium is a multi-component and weakly collisional system generally observed to be in a fully turbulent regime [1,2]. The system dynamics at short spatial scales appears to be dominated by kinetic effects that drive the interstellar gas far from the configuration of thermodynamic equilibrium [3-5]. We present a numerical analysis of a turbulent plasma composed of kinetic ions (protons and alpha particles) and fluid electrons in the typical conditions of the solar-wind environment, developed by using a low-noise hybrid Vlasov-Maxwell code [6,7] in a five dimensional phase space configuration (two dimensions in physical space and three dimensions in velocity space) [8]. The ion dynamics at short spatial scales (shorter than the proton skin depth) display several interesting aspects, mainly consisting in the departure of the distribution functions from the typical Maxwellian configuration, which has been systematically quantified through the evalutation of the temperature anisotropy ratio (perpendicular to parallel temperature ratio) with respect to the local magnetic field. This temperature anisotropy appears to be a direct effect of the turbulent nature of the system dynamics. Moreover, the turbulent activity leads to the generation of coherent structures, such as vortices and current sheets. Conditioned ion temperature distributions suggest heating associated with coherent structures; the distribution of ion temperatures moves towards higher values with increasing PVI threshold for the upper inertial range in the turbulent spectra. This behavior is more evident for alpha particles than for protons. The physical phenomenology recovered in these numerical simulations reproduces very common features recovered in 'in situ' measurements in the turbulent solar wind [9-11], suggesting that the multi-ion Vlasov model represents a valid approach to the understanding of the nature of complex kinetic effects in astrophysical plasmas. [1] R. Bruno and V. Carbone, LRSP 2, 4 (2005) [2] E. Marsch, LRSP 3, 1 (2006) [3] E. Marsch, K.-H. Mühlh.user, R. Schwenn, et al., J. Geophys. Res. 87, A1 (1982) [4] E. Marsch, K.-H. Mühlh.user, R. Schwenn, et al., J. Geophys. Res. 35, A1 (1982) [5] J.C. Kasper, A.J. Lazarus and S.P. Gary, Phys. Rev. Lett. 101, 261103 (2008) [6] F. Valentini, P. Trávnícek, F. Califano et al., J. Comput. Phys. 225, 753 (2007) [7] D. Perrone, F. Valentini and P. Veltri, Astrophys. J. 741, 43 (2011) [8] D. Perrone, F. Valentini, S. Servidio et al., Astrophys. J. 762, 99 (2013) [9] B.A. Maruca, J.C. Kasper and S.P. Gary, Astrophys. J. 748, 137 (2012) [10] S. Bourouaine, E. Marsch and F.M. Neubauer, Astron. and Astrophys. 536, A39 (2011) [11] P. Wu, S. Perri, K. Osman, et al., Astrophys. J. Lett. 763, L30 (2013)

Continuum viscoplastic simulation of a granular column collapse on large slopes : μ(I) rheology and lateral wall effects

NASA Astrophysics Data System (ADS)

Martin, Nathan; Mangeney, Anne; Ionescu, Ioan; Bouchut, Francois

2016-04-01

The description of the mechanical behaviour of granular flows and in particular of the static/flowing transition is still an open and challenging issue with strong implication for hazard assessment [{Delannay et al.}, 2016]. In particular, {detailed quantitative} comparison between numerical models and observations is necessary to go further in this direction. We simulate here dry granular flows resulting from the collapse of granular columns on an inclined channel (from horizontal to 22^o) and compare precisely the results with laboratory experiments performed by {Mangeney et al.} [2010] and {Farin et al.} [2014]. Incompressibility is assumed despite the dilatancy observed in the experiments (up to 10%). The 2-D model is based on the so-called μ(I) rheology that induces a Drucker-Prager yield stress and a variable viscosity. A nonlinear Coulomb friction term, representing the friction on the lateral walls of the channel is added to the model. We demonstrate that this term is crucial to accurately reproduce granular collapses on slopes higher than 10o whereas it remains of little effect on horizontal slope [{Martin et al.}, 2016]. We show that the use of a variable or a constant viscosity does not change significantly the results provided that these viscosities are of the same order [{Ionescu et al.}, 2015]. However, only a fine tuning of the constant viscosity (η = 1 Pa.s) makes it possible to predict the slow propagation phase observed experimentally on large slopes. This was not possible when using, without tuning, the variable viscosity calculated from the μ(I) rheology with the parameters estimated from experiments. Finally, we discuss the well-posedness of the model with variable and constant viscosity based in particular on the development of shear bands observed in the numerical simulations. References Delannay, R., Valance, A., Mangeney, A., Roche, O., and Richard, P., 2016. Granular and particle-laden flows: from laboratory experiments to field observations, {J. Phys. D: Appl. Phys.}, submitted. Farin, M., Mangeney, A., and Roche, O., 2014. Dynamics, deposit and erosion processes in granular collapse over sloping beds, {J. Geophys. Res. Earth Surf.}, 119(3), 504-532. Ionescu, I., Mangeney, A., Bouchut, F., and Roche, O., 2015. Viscoplastic modelling of granular column collapse with pressure and rate dependent viscosity, {J. Non-Newtonian Fluid Mech.}, 219, 1-18. Mangeney, A., Roche, O., Hungr, O., Mangold, Faccanoni, G., and Lucas, A., 2010. Erosion and mobility in granular collapse over sloping beds, {J. Geophys. Res.-Earth Surf.}, 115, F03040. Martin, N., Ionescu, I. R., Mangeney, A., Bouchut, F. and Farin, M., Continuum viscoplastic simulation of a granular column collapse on large slopes: μ(I) rheology and lateral wall effects, submitted.

Study of Fractal Features of Geomagnetic Activity Through an MHD Shell Model

NASA Astrophysics Data System (ADS)

Dominguez, M.; Nigro, G.; Munoz, V.; Carbone, V.

2013-12-01

Studies on complexity have been of great interest in plasma physics, because they provide new insights and reveal possible universalities on issues such as geomagnetic activity, turbulence in laboratory plasmas, physics of the solar wind, etc. [1, 2]. In particular, various studies have discussed the relationship between the fractal dimension, as a measure of complexity, and physical processes in magnetized plasmas such as the Sun's surface, the solar wind and the Earth's magnetosphere, including the possibility of forecasting geomagnetic activity [3, 4, 5]. Shell models are low dimensional dynamical models describing the main statistical properties of magnetohydrodynamic (MHD) turbulence [6]. These models allow us to describe extreme parameter conditions hence reaching very high Reynolds (Re) numbers. In this work a MHD shell model is used to describe the dissipative events which are taking place in the Earth's magnetosphere and causing geomagnetic storms. The box-counting fractal dimension (D) [7] is calculated for the time series of the magnetic energy dissipation rate obtained in this MHD shell model. We analyze the correlation between D and the energy dissipation rate in order to make a comparison with the same analysis made on the geomagnetic data. We show that, depending on the values of the viscosity and the diffusivity, the fractal dimension and the occurrence of bursts exhibit correlations similar as those observed in geomagnetic and solar data, [8] suggesting that the latter parameters could play a fundamental role in these processes. References [1] R. O. Dendy, S. C. Chapman, and M. Paczuski, Plasma Phys. Controlled Fusion 49, A95 (2007). [2] T. Chang and C. C. Wu, Phys. Rev. E 77, 045401 (2008). [3] R. T. J. McAteer, P. T. Gallagher, and J. Ireland, Astrophys. J. 631, 628 (2005). [4] V. M. Uritsky, A. J. Klimas, and D. Vassiliadis, Adv. Space Res. 37, 539 (2006). [5] S. C. Chapman, B. Hnat, and K. Kiyani, Nonlinear Proc. Geophys. 15, 445 (2008). [6] G. Boffetta, V. Carbone, P. Giuliani, P. Veltri, and A. Vulpiani, Phys. Rev. Lett. 83, 4662 (1999). [7] P. S. Addison, Fractals and Chaos, an Illustrated Course, vol. 1 (Institute of Physics Publishing, Bristol and Philadelphia, 1997), second ed. [8] M. Domínguez, V. Muñoz, and J. A. Valdivia, Temporal evolution of fractality in the Earth's magnetosphere and the solar photosphere, in preparation.

Charactering biomass burning aerosol in the Weather Research and Forecasting model with Chemistry (WRF-Chem), with evaluation against SAMBBA flight data.

NASA Astrophysics Data System (ADS)

Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W.; Freitas, S. R.; Longo, K.; Coe, H.; McFiggans, G.

2014-12-01

The burning of forests in the Amazonia region is a globally significant source of carbonaceous aerosol, containing both absorbing and scattering components. Biomass burning aerosol (BBA) are efficient CCN, modifying cloud properties and influencing atmospheric circulation and precipitation tendencies. The impacts of BBA are highly dependent on their size distribution and composition. Studies in this region can therefore benefit greatly from the use of state-of-the-art sectional aerosol representations. A bottom-up fire emissions inventory, 3BEM, has been developed by Longo et al.1. It uses satellite products to identify fire locations, applying the emissions factors of Andrei and Merlot3 to generate daily emission maps. Flaming emissions are very buoyant, and a method for injecting emissions at altitude is needed to accurately describe the vertical profile of BBA. A parameterisation has been developed to simulate this sub-grid process4, and previously implemented in WRF-Chem using a modal aerosol scheme5. For this work we have modified the WRF-Chem model to simulate 3BEM emissions using the MOSAIC sectional aerosol scheme6. This modified version of WRF-Chem v3.4.1 has been run for September 2012 over South America (25km grid-spacing). We will present model results evaluating the modelled aerosol vertical distribution, size distribution, composition and optical properties against measurements taken by the FAAM BAe-146 research aircraft during the SAMBBA field campaign. The plume-rise parameterisation was found to inject flaming emissions too high over most fires, resulting in high modelled aerosol loadings at high altitude. We probed the behaviour of the parameterisation by developing a new SAMBBA-tuned 3BEM emissions scenario, which uses more realistic estimates of fire size. Results from high-resolution (5 and 1km) nested simulations will also be presented, in order to evaluate the impacts of explicit aerosol-cloud interactions in non-parameterised clouds. 1. K. Longo et al., 2010, Atmos. Chem. Phys., 10, 5785-5795. 2. M. O. Andreae and P. Merlot, 2001, Global Biogeochem. Cy., 15(4), 955-966. 3. S. Freitas et al., 2007, Atmos. Chem. Phys., 7, 3385-3398. 4. G. Grell et al., 2011, Atmos. Chem. Phys., 11, 5289-5303. 5. R. Zavari et al., 2008, J. Geophys. Res., 113, D132024.

Using collaborative technology to enhance pre-service teachers' pedagogical content knowledge in Science

NASA Astrophysics Data System (ADS)

Donnelly, Dermot Francis; Hume, Anne

2015-01-01

Background:Supporting pre-service teacher (PT) collaboration as a means of professional learning is a challenging but essential task for effective practice. However, teacher placements or practicums in schools, which is common practice within teacher education programmes, can often isolate PTs from sharing their experiences with each other. Further, the articulation of effective pedagogical practices by high-quality teachers is limited, restricting PTs' ability to access such professional knowledge. Purpose:This study investigates how the introduction of a collaborative technology, a wiki, may enhance existing and new opportunities for pre-service teachers' (PTs) to develop pedagogical content knowledge (PCK). Sample:Seven PT chemistry teachers of varied backgrounds participated in this study. Design and method:The PTs were learning to collaboratively formulate and document their early topic-specific teaching knowledge using a pedagogical tool known as Content Representation (CoRe) design. Once scaffolded into this process, the PTs continued and extended this collaborative work online through the introduction of a wiki. Data were collected for qualitative analysis through the CoRe artefacts, a semi-structured focus group interview, and PTs' reflective essays about their collaborative experiences representing their teaching knowledge in CoRes through the wiki. Results:Data analysis highlighted that while wiki use showed some potential for collaborative representation when participants were not face-to-face, the PTs were hesitant in critiquing each other's work. As such, the online representations remained relatively static without face-to-face interaction. However, developing artefacts online was favoured over established practice and the access to artefacts of their peers on the wiki enhanced PTs' consideration for their own PCK. Conclusion:Wikis show some potential in the hosting of CoRes, but issues in simultaneous posting and lack of chat functionality may hinder PTs' ability to easily critique each others' work. However, the PTs in this study also demonstrated a broader unwillingness to critique each other's CoRes that teacher educators need to challenge. The use of technology to support PTs' CoRes and critiquing warrants further research.

Responding to Students' Learning Preferences in Chemistry

NASA Astrophysics Data System (ADS)

Lewthwaite, Brian; Wiebe, Rick

2014-04-01

This paper reports on a teacher's and his students' responsiveness to a new tetrahedral-oriented (Mahaffy in J Chem Educ 83(1):49-55, 2006) curriculum requiring more discursive classroom practices in the teaching of chemistry. In this instrumental case study, we identify the intentions of this learner-centered curriculum and a teacher's development in response to this curriculum. We also explore the tensions this teacher experiences as students subsequently respond to his adjusted teaching. We use a Chemistry Teacher Inventory (Lewthwaite and Wiebe in Res Sci Educ 40(11):667-689, 2011; Lewthwaite and Wiebe in Can J Math Sci Technol Educ 12(1):36-61, 2012; Lewthwaite in Chem Educ Res Pract. doi:10.1039/C3RP00122A, 2014) to assist the teacher in monitoring how he teaches and how he would like to improve his teaching. We also use a student form of the instrument, the Chemistry Classroom Inventory and Classroom Observation Protocol (Lewthwaite and Wiebe 2011) to verify the teacher's teaching and perception of student preferences for his teaching especially in terms of the discursive processes the curriculum encourages. By so doing, the teacher is able to use both sets of data as a foundation for critical reflection and work towards resolution of the incongruence in data arising from students' preferred learning orientations and his teaching aspirations. Implications of this study in regards to the authority of students' voice in triggering teachers' pedagogical change and the adjustments in `teachering' and `studenting' required by such curricula are considered.

Synergistic effect of PEGylated resveratrol on delivery of anticancer drugs.

PubMed

Wang, Wenlong; Zhang, Liang; Le, Yuan; Chen, Jian-Feng; Wang, Jiexin; Yun, Jimmy

2016-02-10

Resveratrol (RES) is a natural polyphenol which can be considered as a nutraceutical because of its benefits such as anticancer and antioxidant activity. In this paper, we designed polymer-RES conjugates as anticancer drug carrier for synergistic therapeutic effect in cancer treatment. Bicalutamide (BIC) was used as a model drug to investigate the drug release behaviors and in vitro anticancer performance. PEG-RES and PEG-Glycine-RES nanoparticles were prepared and characterized. The size of the prepared particles was around 50 nm with RES content of 17.2 and 16.3 wt% for PEG-RES and PEG-Glycine-RES, respectively, and BIC loading efficiency were of 81.6% and 84.5%, separately. Release rate of RES from conjugates depended on the stability of ester group against hydrolysis. BIC release was much faster than RES release. The anticancer activity of BIC loaded PEGylated RES nanoparticles was much better than that of free BIC, indicating the conjugates provided a synergetic cytotoxicity to cancer cells. Confocal laser scanning microscopy observation and flow cytometry analyses indicated that PEGylated RES conjugates were more efficiently internalized into cells, released drug into cytoplasm. These results suggest that PEGylated RES conjugates show great potential for cancer therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

Overview of long-term field experiments in Germany - metadata visualization

NASA Astrophysics Data System (ADS)

Muqit Zoarder, Md Abdul; Heinrich, Uwe; Svoboda, Nikolai; Grosse, Meike; Hierold, Wilfried

2017-04-01

BonaRes ("soil as a sustainable resource for the bioeconomy") is conducting to collect data and metadata of agricultural long-term field experiments (LTFE) of Germany. It is funded by the German Federal Ministry of Education and Research (BMBF) under the umbrella of the National Research Strategy BioEconomy 2030. BonaRes consists of ten interdisciplinary research project consortia and the 'BonaRes - Centre for Soil Research'. BonaRes Data Centre is responsible for collecting all LTFE data and regarding metadata into an enterprise database upon higher level of security and visualization of the data and metadata through data portal. In the frame of the BonaRes project, we are compiling an overview of long-term field experiments in Germany that is based on a literature review, the results of the online survey and direct contacts with LTFE operators. Information about research topic, contact person, website, experiment setup and analyzed parameters are collected. Based on the collected LTFE data, an enterprise geodatabase is developed and a GIS-based web-information system about LTFE in Germany is also settled. Various aspects of the LTFE, like experiment type, land-use type, agricultural category and duration of experiment, are presented in thematic maps. This information system is dynamically linked to the database, which means changes in the data directly affect the presentation. An easy data searching option using LTFE name, -location or -operators and the dynamic layer selection ensure a user-friendly web application. Dispersion and visualization of the overlapping LTFE points on the overview map are also challenging and we make it automatized at very zoom level which is also a consistent part of this application. The application provides both, spatial location and meta-information of LTFEs, which is backed-up by an enterprise geodatabase, GIS server for hosting map services and Java script API for web application development.

Simulation of the Physics of Flight

ERIC Educational Resources Information Center

Lane, W. Brian

2013-01-01

Computer simulations continue to prove to be a valuable tool in physics education. Based on the needs of an Aviation Physics course, we developed the PHYSics of FLIght Simulator (PhysFliS), which numerically solves Newton's second law for an airplane in flight based on standard aerodynamics relationships. The simulation can be used to pique…

Productive Resources in Students' Ideas about Energy: An Alternative Analysis of Watts' Original Interview Transcripts

ERIC Educational Resources Information Center

Harrer, Benedikt W.; Flood, Virginia J.; Wittmann, Michael C.

2013-01-01

For over 30 years, researchers have investigated students' ideas about energy with the intent of reforming instructional practice. In this pursuit, Watts contributed an influential study with his 1983 paper "Some alternative views of energy" ["Phys. Educ." 18, 213 (1983)]. Watts' "alternative frameworks"…

Geometry and the Physics of Seasons

ERIC Educational Resources Information Center

Khavrus, Vyacheslav; Shelevytsky, Ihor

2012-01-01

By means of a simple mathematical model recently developed by the authors (2010 "Phys. Educ." 45 641), the passage of the seasons on the Earth is simulated for arbitrary latitudes, taking into account sunlight attenuation in the atmosphere. The method developed can be used to predict a realistic value of the solar energy input (insolation) that…

Interactions of Ultracold Impurity Particles with Bose-Einstein Condensates

DTIC Science & Technology

2015-06-23

Lukin et al ., Phys. Rev. Lett. 87, 037901 (2001). [2] D. Jaksch et al ., Phys. Rev. Lett. 85, 2208 (2000). [3] L. Isenhower et al ., Phys. Rev. Lett...104, 010503 (2010). [4] T. Wilk et al ., Phys. Rev. Lett. 104, 010502 (2010). [5] I. Mourachko et al ., Phys. Rev. Lett. 80, 253 (1998). [6] W. R...Phys. 12, 103044 (2010). [12] R. M. W. van Bijnen et al ., J. Phys. B 44, 184008 (2011). [13] I. Lesanovsky, Phys. Rev. Lett. 106, 025301 (2011). [14] E

Co-encapsulated resveratrol and quercetin in chitosan and peg modified chitosan nanoparticles: For efficient intra ocular pressure reduction.

PubMed

Natesan, Subramanian; Pandian, Saravanakumar; Ponnusamy, Chandrasekar; Palanichamy, Rajaguru; Muthusamy, Sivakumar; Kandasamy, Ruckmani

2017-11-01

Natural anti-oxidants resveratrol (RES) and quercetin (QUR) posses the ability to reduce intra ocular pressure efficiently. Concurrent administration of RES and QUR was able to enhance the bioavailability of RES. Present research work describes upsurge of QUR in RES loaded chitosan (CS) nanoparticles (NPs) and polyethylene glycol (PEG) modified CS NPs for improved delivery and synergic effects on reducing intra ocular pressure for the treatment of glaucoma. CS NPs and PEG modified CS NPs were prepared by ionic gelation of tripolyphosphate and CS. The synthesised NPs were spherical in shape and RES entrapment and loading efficiency in the formulation decreased with increasing PEG concentration. Particle size of the formulation increased while incorporating PEG and drugs. The crystalline nature of RES and QUR changed in the NPs and that was confirmed by XRD study. Free radical neutralising efficiency improved while incorporating QUR in the formulation. Ex-vivo corneal permeation of RES was higher from RES and QUR loaded formulation than RES alone containing NPs and free RES dispersion. RES and QUR loaded PEG modified CS NPs showed sustained and enhanced reduction of intra ocular pressure (5.5±0.5mmHg) in normotensive rabbits. Copyright © 2017 Elsevier B.V. All rights reserved.

The Quality of Pre-Service Science Teachers' Argumentation: Influence of Content Knowledge

ERIC Educational Resources Information Center

Cetin, Pinar Seda; Dogan, Nihal; Kutluca, Ali Yigit

2014-01-01

Research exploring the possible link between quality of argumentation and content knowledge is not straightforward. Some studies suggest a positive relationship (e.g. Dawson & Schibeci in "J Biol Educ" 38(1):7-12, 2003) while others do not (e.g. Zohar & Nemet in "J Res Sci Teach" 39:35-62, 2002). This study examined the…

Fifty years of Jaynes-Cummings physics

NASA Astrophysics Data System (ADS)

Greentree, Andrew D.; Koch, Jens; Larson, Jonas

2013-11-01

This special issue commemorates the 50th anniversary of the seminal paper published by E T Jaynes and F W Cummings [1], the fundamental model which they introduced and now carries their names, and celebrates the remarkable host of exciting research on Jaynes-Cummings physics throughout the last five decades. The Jaynes-Cummings model has been taking the prominent stance as the 'hydrogen atom of quantum optics' [2]. Generally speaking, it provides a fundamental quantum description of the simplest form of coherent radiation-matter interaction. The Jaynes-Cummings model describes the interaction between a single electromagnetic mode confined to a cavity, and a two-level atom. Energy is exchanged between the field and the atom, which leads directly to coherent population oscillations (Rabi oscillations) and superposition states (dressed states). Being exactly solvable, the Jaynes-Cummings model serves as a most useful toy model, and as such it is a textbook example of the physicists' popular strategy of simplifying a complex problem to its most elementary constituents. Thanks to the simplicity of the Jaynes-Cummings model, this caricature of coherent light-matter interactions has never lost its appeal. The Jaynes-Cummings model is essential when discussing experiments in quantum electrodynamics (indeed the experimental motivation of the Jaynes-Cummings model was evident already in the original paper, dealing as it does with the development of the maser), and it has formed the starting point for much fruitful research ranging from ultra-cold atoms to cavity quantum electrodynamics. In fact, Jaynes-Cummings physics is at the very heart of the beautiful experiments by S Haroche and D Wineland, which recently earned them the 2012 Nobel Prize in physics. Indeed, as with most significant models in physics, the model is invoked in settings that go far beyond its initial framework. For example, recent investigations involving multi-level atoms, multiple atoms [3, 4], multiple electromagnetic modes, arrays of coupled cavities [5-7], and optomechanical systems [8] have further enriched the physics of the Jaynes-Cummings model. From the early interests in masers and the consistent quantum description of radiation and atom-photon interaction, the Jaynes-Cummings model has evolved into a cornerstone of quantum state engineering [9]. The authors of this editorial had not been born when Jaynes and Cummings wrote their remarkable paper. It is, therefore, a special honour for us to be able to draw the reader's attention to the accompanying reminiscence contributed by Frederick Cummings where he gives us a glimpse of the early history of the Jaynes-Cummings model from his perspective [11]. By now, the original 1963 paper by Jaynes and Cummings has gathered numerous citations and, at the time of writing, the number of articles involving Jaynes-Cummings physics is approaching 15 000.1 This special issue does not attempt to review this impressive wealth of research. The interested reader, however, is urged to consult the definitive article by Shore and Knight [10] for a comprehensive review of the first 30 years of Jaynes-Cummings physics. The collection of 26 papers presented in this issue, showcases a snapshot of some of the most recent and continuing research devoted to Jaynes-Cummings physics. We begin our special issue with Professor Cumming's recollections [11]. We then have six papers on quantum information aspects of the Jaynes-Cummings model [12-17]. The next topic includes seven papers on the Dicke and generalized Jaynes-Cummings models [18-24], followed by six papers on circuit QED, which is one of the most important experimental frameworks for Jaynes-Cummings systems [25-30]. Finally, we have six papers on the extension to many cavities, the Jaynes-Cummings-Hubbard model [31-36]. The snapshot of research captured in this special issue illustrates the unifying language provided by the Jaynes-Cummings model, tying together research in a number of subfields in physics. Jaynes-Cummings physics started with the diagonalization of a 2 × 2 matrix, as Frederick Cummings points out. There is no doubt that this elegance of simplicity will continue to guide exciting new research in the decades to come. References [1] Jaynes E T and Cummings F W 1963 Comparison of quantum and semiclassical radiation theories with application to the beam maser Proc. IEEE 51 89 [2] Shore B W and Knight P L 2004 Physics and Probability: Essays in Honor of Edwin T Jaynes (Cambridge: Cambridge University Press) [3] Tavis M and Cummings F W 1968 Exact solution for an N -molecule-radiation-field Hamiltonian Phys. Rev. 170 379-84 [4] Tavis M and Cummings F W 1969 Approximate solutions for an N -molecule-radiation-field Hamiltonian Phys. Rev. 188 692-5 [5] Hartmann M J, Brandão F G S L and Plenio M B 2006 Strongly interacting polaritons in coupled arrays of cavities Nature Phys. 2 849-55 [6] Greentree A D, Tahan C, Cole J H and Hollenberg L C L 2006 Quantum phase transitions of light Nature Phys. 2 856-61 [7] Angelakis D G, Santos M F and Bose S 2007 Photon-blockade-induced Mott transitions and XY spin models in coupled cavity arrays Phys. Rev. A 76 031805(R) [8] Schwab K C and Roukes M L 2005 Putting mechanics into quantum mechanics Phys. Today 58 36-42 [9] Blatt R, Milburn G J and Lvovksy A 2013 The 20th anniversary of quantum state engineering J. Phys. B: At. Mol. Opt. Phys. 46 100201 [10] Shore B and Knight P L 1993 The Jaynes-Cummings model J. Mod. Opt. 40 1195-238 [11] Cummings F W 2013 J. Phys. B: At. Mol. Opt. Phys. 46 220202 [12] Arenz C 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224001 [13] Quesada N 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224002 [14] Everitt M 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224003 [15] Kitajima S 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224004 [16] Groves E 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224005 [17] Bougouffa S 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224006 [18] Braak D 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224007 [19] Emary C 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224008 [20] Miroshnychenko Y 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224009 [21] Dombi A 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224010 [22] Tavis M 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224011 [23] Grimsmo A 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224012 [24] Stenholm S I 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224013 [25] Kockum A F 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224014 [26] Larson J 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224015 [27] Larson J 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224016 [28] Agarwal S 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224017 [29] Deng W-W 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224018 [30] Leppaekangas J 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224019 [31] Schmidt S 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224020 [32] Schiro M 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224021 [33] Susa C 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224022 [34] del Valle E 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224023 [35] Correa B V 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224024 [36] Schetakis N 2013 J. Phys. B: At. Mol. Opt. Phys. 46 224025 1Number estimate based on a Google Scholar search.

The Intersection of Inquiry-Based Science and Language: Preparing Teachers for ELL Classrooms

NASA Astrophysics Data System (ADS)

Weinburgh, Molly; Silva, Cecilia; Smith, Kathy Horak; Groulx, Judy; Nettles, Jenesta

2014-08-01

As teacher educators, we are tasked with preparing prospective teachers to enter a field that has undergone significant changes in student population and policy since we were K-12 teachers. With the emphasis placed on connections, mathematics integration, and communication by the New Generation Science Standards (NGSS) (Achieve in Next generation science standards, 2012), more research is needed on how teachers can accomplish this integration (Bunch in Rev Res Educ 37:298-341, 2013; Lee et al. in Educ Res 42(4):223-233, 2013). Science teacher educators, in response to the NGSS, recognize that it is necessary for pre-service and in-service teachers to know more about how instructional strategies in language and science can complement one another. Our purpose in this study was to explore a model of integration that can be used in classrooms. To do this, we examined the change in science content knowledge and academic vocabulary for English language learners (ELLs) as they engaged in inquiry-based science experience utilizing the 5R Instructional Model. Two units, erosion and wind turbines, were developed using the 5R Instructional Model and taught during two different years in a summer school program for ELLs. We analyzed data from interviews to assess change in conceptual understanding and science academic vocabulary over the 60 h of instruction. The statistics show a clear trend of growth supporting our claim that ELLs did construct more sophisticated understanding of the topics and use more language to communicate their knowledge. As science teacher educators seek ways to prepare elementary teachers to help preK-12 students to learn science and develop the language of science, the 5R Instructional Model is one pathway.

The New Phys Ed.: Dodgeball Is Passe; Schools Are Teaching Lifelong Fitness

ERIC Educational Resources Information Center

Schachter, Ron

2011-01-01

A growing number of physical education teachers are introducing a new kind of P.E. in schools, emphasizing lifelong activities such as running, cycling, yoga, and skateboarding, in an attempt to make exercise more engaging--and lifelong--for elementary and middle school students. The new generation of P.E. classes is introducing youngsters to…

The Physics of Flight: I. Fixed and Rotating Wings

ERIC Educational Resources Information Center

Linton, J. Oliver

2007-01-01

Almost all elementary textbook explanations of the theory of flight rely heavily on Bernoulli's principle and the fact that air travels faster over a wing than below it. In recent years the inadequacies and, indeed, fallacies in this explanation have been exposed (see Babinsky's excellent article in 2003 Phys. Educ. 38 497-503) and it is now…

Resveratrol inhibits estrogen-induced breast carcinogenesis through induction of NRF2-mediated protective pathways

PubMed Central

Singh, Bhupendra; Shoulson, Rivka; Chatterjee, Anwesha; Ronghe, Amruta; Bhat, Nimee K.; Dim, Daniel C.; Bhat, Hari K.

2014-01-01

The importance of estrogens in the etiology of breast cancer is widely recognized. Estrogen-induced oxidative stress has been implicated in this carcinogenic process. Resveratrol (Res), a natural antioxidant phytoestrogen has chemopreventive effects against a variety of illnesses including cancer. The objective of the present study was to characterize the mechanism(s) of Res-mediated protection against estrogen-induced breast carcinogenesis. Female August Copenhagen Irish rats were treated with 17β-estradiol (E2), Res and Res + E2 for 8 months. Cotreatment of rats with Res and E2 inhibited E2-mediated proliferative changes in mammary tissues and significantly increased tumor latency and reduced E2-induced breast tumor development. Resveratrol treatment alone or in combination with E2 significantly upregulated expression of nuclear factor erythroid 2-related factor 2 (NRF2) in mammary tissues. Expression of NRF2-regulated antioxidant genes NQO1, SOD3 and OGG1 that are involved in protection against oxidative DNA damage was increased in Res- and Res + E2-treated mammary tissues. Resveratrol also prevented E2-mediated inhibition of detoxification genes AOX1 and FMO1. Inhibition of E2-mediated alterations in NRF2 promoter methylation and expression of NRF2 targeting miR-93 after Res treatment indicated Res-mediated epigenetic regulation of NRF2 during E2-induced breast carcinogenesis. Resveratrol treatment also induced apoptosis and inhibited E2-mediated increase in DNA damage in mammary tissues. Increased apoptosis and decreased DNA damage, cell migration, colony and mammosphere formation in Res- and Res + E2-treated MCF-10A cells suggested a protective role of Res against E2-induced mammary carcinogenesis. Small-interfering RNA-mediated silencing of NRF2 inhibited Res-mediated preventive effects on the colony and mammosphere formation. Taken together, these results suggest that Res inhibits E2-induced breast carcinogenesis via induction of NRF2-mediated protective pathways. PMID:24894866

ISICS2008: An expanded version of ISICS for calculating K-, L-, and M-shell cross sections from PWBA and ECPSSR theory

NASA Astrophysics Data System (ADS)

Cipolla, Sam J.

2009-09-01

New version program summaryProgram title: ISICS2008 Catalogue identifier: ADDS_v4_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADDS_v4_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5420 No. of bytes in distributed program, including test data, etc.: 107 669 Distribution format: tar.gz Programming language: C Computer: 80 486 or higher level PCs Operating system: Windows XP and all earlier operating systems Classification: 16.7 Catalogue identifier of previous version: ADDS_v3_0 Journal reference of previous version: Comput. Phys. Comm. 179 (2008) 616 Does the new version supersede the previous version?: Yes Nature of problem: Ionization and X-ray production cross section calculations for ion-atom collisions. Solution method: Numerical integration of form factor using a logarithmic transform and Gaussian quadrature, plus exact integration limits. Reasons for new version: Addition of relativistic treatment of both projectile and K-shell electrons. Summary of revisions: A new addition to ISICS is the option (R) to calculate ECPSSR cross sections that account for the relativistic treatment of both projectile and K-shell electron, as proposed recently by Lapicki [1], accordingly as σKRECPSSR=Cṡ(1+0.07(()ṡσ(√{(mKRυ1R)}/Z,ςθ), where υ1R is the relativistic projectile velocity. The option can also be invoked in calculating ECPSShsR, where hsR stands for the Hartree-Slater description of the K-shell electron, which was already incorporated into ISICS2006 [2,3], and is now expressed in this option as, σKRECPSShsR=CṡhsR((2υ1R)/(Zςθ),Z/137)ṡ(1+0.07(()ṡσ(υ1R/Z,ςθ) using the function hsR that is already incorporated into ISICS2006. It should be noted that these expressions are corrected versions [4] from the ones published in Ref. [1]. In this new version, ISICS2008, the option line in the main menu that read "Use Relativistic Proj. velocity" has been replaced by "R option for K-shell … Uses Rel. Proj. vel.". As before, various combinations of options can be utilized and each is denoted in the output. Restrictions: The consumed CPU time increases with the atomic shell (K,L,M), but execution is still very fast. Additional comments: A revised User Manual is included in the distribution file. Running time: This depends on which shell and the number of different energies to be used in the calculation. The running time is not significantly changed from the previous version. As before, to calculate K-shell cross sections for protons striking carbon for 19 different proton energies it took less than 10 s; to calculate M-shell cross sections for protons on gold for 21 proton energies it took 4.2 min. References:G. Lapicki, J. Phys. B: At. Mol. Op. Phys. 41 (2008) 115201. S. Cipolla, Comput. Phys. Comm. 176 (2007) 157. S. Cipolla, Nucl. Instrum. Methods Phys. Res. B 261 (2007) 142. G. Lapicki, private communication.

Supplemental progesterone and timing of resynchronization on pregnancy outcomes in lactating dairy cows.

PubMed

Bilby, T R; Bruno, R G S; Lager, K J; Chebel, R C; Moraes, J G N; Fricke, P M; Lopes, G; Giordano, J O; Santos, J E P; Lima, F S; Stevenson, J S; Pulley, S L

2013-01-01

The objective was to determine the effect of exogenous progesterone (P4) in a timed artificial insemination (TAI) protocol initiated at 2 different times post-AI on pregnancies per AI (P/AI) in lactating dairy cows. Cows (n=1,982) in 5 dairy herds were assigned randomly at a nonpregnancy diagnosis 32 ± 3 d post-AI to 1 of 4 resynchronization (RES) treatments arranged in a 2 × 2 factorial design using the Ovsynch-56 (GnRH, 7d later PGF2α, 56 h later GnRH, 16 h later TAI) protocol. Treatments were as follows: cows initiating RES 32 ± 3 d after AI with no supplemental P4 (d 32 RES-CON; n=516); same as d 32 RES-CON plus a controlled internal drug release (CIDR) insert containing P4 at the onset of Ovsynch-56 (d 32 RES-CIDR; n=503); cows initiating RES 39 ± 3 d after AI (d 39 RES-CON; n=494); and same as d 39 RES-CON plus a CIDR (d 39 RES-CIDR; n=491). Cows were inseminated if observed in estrus before TAI. The P/AI was determined 32 and 60 d after TAI. In a subgroup of cows (n=1,152), blood samples were collected and ovarian structures examined by ultrasonography on the days of the first GnRH (G1) and PGF2α of Ovsynch-56. Percentage of cows with a corpus luteum (CL) at G1 was unaffected by timing of treatments, but percentage of cows with a CL at PGF2α was greater for d 32 than for d 39 cows (87.9 vs. 79.4%). In addition, percentage of cows with P4 ≥ 1 ng/mL at G1 was unaffected by timing of treatments, but was increased for d 32 compared with d 39 RES cows on the day of the PGF2α of the RES protocols (86.5 vs. 74.3%). Treatment did not affect ovulation to G1 or P/AI 32 d after RES TAI (d 32 RES-CON=30.1%, d 32 RES-CIDR=28.8%, d 39 RES-CON=27.5%, d 39 RES-CIDR=30.5%). A greater percentage of d 39 RES cows underwent premature luteolysis during the RES protocol compared with d 32 RES cows. An interaction was detected between day of RES initiation and CIDR treatment, in which the CIDR increased P/AI 60 d after TAI for d 39 (CON=23.7% vs. CIDR=28.0%), but not for d 32 (CON=26.9% and CIDR=24.2%) cows. Pregnancy loss was unaffected by treatment. In addition, cows had improved P/AI 60 d after TAI when they received a CIDR and did not have a CL (CON-CL=28.2%, CON-No CL=19.2%, CIDR-CL=27.0%, and CIDR-No CL=26.5%) or had P4 <1 ng/mL (CON-High P4=27.8%, CON-Low P4=15.0%, CIDR-High P4=25.0%, and CIDR-Low P4=29.4%) at G1, but not if a CL was present or P4 was ≥ 1 ng/mL at G1. In conclusion, addition of a CIDR insert to supplement P4 during the RES protocol increased P/AI for cows initiating RES 39 ± 3 d after AI but not 32 ± 3 d after AI. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Pulmonary Metabolism of Resveratrol: In Vitro and In Vivo Evidence

PubMed Central

Sharan, Satish

2013-01-01

The role of pulmonary metabolism in trans-resveratrol (RES) pharmacokinetics was studied in a mouse model. Plasma concentrations of RES and its major metabolites trans-resveratrol-3-sulfate (R3S) and trans-resveratrol-3-glucuronide (R3G) were compared after administration of RES by intravenous (IV) and intra-arterial (IA) routes. Total area under the curve (AUC) of RES decreased by approximately 50% when RES was administered by the IV route compared with the IA route. The AUC of R3G was also significantly higher in mice administered RES by the IV route compared with the IA route. In vitro studies performed with mouse and human lung fractions confirmed pulmonary metabolism of RES. Interestingly, mouse-lung fractions gave rise to both R3S and R3G, whereas human lung fractions yielded R3S. This indicates marked interspecies variation in RES conjugation, especially in the context of extrapolating rodent data to humans. Taken together, the results presented here underline, for the first time, the impact of pulmonary metabolism on resveratrol pharmacokinetics and interspecies differences in RES pulmonary metabolism. PMID:23474649

Toward the sociopolitical in science education

NASA Astrophysics Data System (ADS)

Tolbert, Sara; Bazzul, Jesse

2017-06-01

In this paper, we explore how Jacques Rancière's (The ignorant schoolmaster: five lessons in intellectual emancipation. Stanford University Press, Stanford, 1991) notions of radical equality and dissensus reveal horizons for activism and sociopolitical engagement in science education theory, research, and practice. Drawing on Rochelle Gutiérrez' (J Res Math Educ 44(1):37-68, 2013a. doi: 10.5951/jresematheduc.44.1.0037; J Urban Math Educ 6(2):7-19, b) "sociopolitical turn" for mathematics education, we identify how the field of science education can/is turning from more traditional notions of equity, achievement and access toward issues of systemic oppression, identity and power. Building on the conversation initiated by Lorraine Otoide who draws from French philosopher Jacques Rancière to experiment with a pedagogy of radical equality, we posit that a sociopolitical turn in science education is not only imminent, but necessary to meet twenty-first century crises.

KANSAS WIND POWERING AMERICAN STATE OUTREACH: KANSAS WIND WORKING GROUP

DOE Office of Scientific and Technical Information (OSTI.GOV)

HAMMARLUND, RAY

2010-10-27

The Kansas Wind Working Group (WWG) is a 33-member group announced by former Governor Kathleen Sebelius on Jan. 7, 2008. Formed through Executive Order 08-01, the WWG will educate stakeholder groups with the current information on wind energy markets, technologies, economics, policies, prospects and issues. Governor Mark Parkinson serves as chair of the Kansas Wind Working Group. The group has been instrumental in focusing on the elements of government and coordinating government and private sector efforts in wind energy development. Those efforts have moved Kansas from 364 MW of wind three years ago to over 1000 MW today. Further, themore » Wind Working Group was instrumental in fleshing out issues such as a state RES and net metering, fundamental parts of HB 2369 that was passed and is now law in Kansas. This represents the first mandatory RES and net metering in Kansas history.« less

Electron heating and energy inventory during asymmetric reconnection in a laboratory plasma

NASA Astrophysics Data System (ADS)

Yoo, J.; Na, B.; Jara-Almonte, J.; Yamada, M.; Ji, H.; Roytershteyn, V.; Argall, M. R.; Fox, W.; Chen, L. J.

2017-12-01

Electron heating and the energy inventory during asymmetric reconnection are studied in the Magnetic Reconnection Experiment (MRX) [1]. In this plasma, the density ratio is about 8 across the current sheet. Typical features of asymmetric reconnection such as the large density gradients near the low-density-side separatrices, asymmetric in-plane electric field, and bipolar out-of-plane magnetic field are observed. Unlike the symmetric case [2], electrons are also heated near the low-density-side separatrices. The measured parallel electric field may explain the observed electron heating. Although large fluctuations driven by lower-hybrid drift instabilities are also observed near the low-density-side separatrices, laboratory measurements and numerical simulations reported here suggest that they do not play a major role in electron energization. The average electron temperature increase in the exhaust region is proportional to the incoming magnetic energy per an electron/ion pair but exceeds the scaling of the previous space observations [3]. This discrepancy is explained by differences in the boundary condition and system size. The profile of electron energy gain from the electric field shows that there is additional electron energy gain associated with the electron diamagnetic current besides a large energy gain near the X-line. This additional energy gain increases electron enthalpy, not the electron temperature. Finally, a quantitative analysis of the energy inventory during asymmetric reconnection is conducted. Unlike the symmetric case where the ion energy gain is about twice more than the electron energy gain [4], electrons and ions obtain a similar amount of energy during asymmetric reconnection. [1] J. Yoo et al., accepted for a publication in J. Geophys. Res. [2] J. Yoo et al., Phys. Plasmas 21, 055706 (2014). [3] T. Phan et al., Geophys. Res. Lett. 40, 4475 (2013). [4] M. Yamada et al., Nat. Comms. 5, 4474 (2014).

Initiation of Negative Streamers from Hydrometeors at Subbreakdown Field Conditions

NASA Astrophysics Data System (ADS)

Shi, F.; Liu, N.; Dwyer, J. R.; Tilles, J.

2017-12-01

Recent high-speed interferometer observations have indicated that the initiation of lightning may begin as compact intracloud discharges (CIDs) [Rison et al., Nat. Commun., 7, 10721, 2016], which are caused by a process termed fast positive breakdown. It is hypothesized that fast positive breakdown consists of a system of positive streamers [Rison et al., 2016]. A follow-up investigation by using the same interferometer has found that CIDs can also be caused by fast negative breakdown [Tilles et al., AE12A-03, AGU Fall Meeting, 2016]. If negative streamers are the underlying process driving fast negative breakdown, this suggests that negative streamers can be initiated and propagate through a significant distance of about one kilometer without detectable signals from positive streamers. However, initiation of negative streamers from isolated hydrometeors in subbreakdown fields has never been reproduced by modeling studies [Liu et al., Phys. Rev. Lett., 109, 025002, 2012; Sadighi et al., J. Geophys. Res. Atmos., 120, 3660, 2015; Shi et al., J. Geophys. Res. Atmos., 121, 7284, 2016]. In this talk, we will show that negative streamers can be successfully initiated from the tip of a cone-shape hydrometeor in an electric field well below conventional breakdown threshold field, suggesting that the shape of a hydrometeor plays an important role in streamer initiation. Formation of positive streamers may follow the initiation of negative streamers, and the characteristics of positive and negative streamers developing in the same subbreakdown field can be very different. For example, the peak field of the positive streamer head is almost two times larger than that of the negative head; the streamer channel density of the positive streamer is larger than that of the negative streamer; and the growth rate of the positive streamer is larger than that of the negative streamer. We will discuss the implications of our modeling results in the context of the observations of fast positive and negative breakdown.

Dependence of radiation belt simulations to assumed radial diffusion rates tested for two empirical models of radial transport

NASA Astrophysics Data System (ADS)

Drozdov, Alexander; Shprits, Yuri; Aseev, Nikita; Kellerman, Adam; Reeves, Geoffrey

2017-04-01

Radial diffusion is one of the dominant physical mechanisms that drives acceleration and loss of the radiation belt electrons, which makes it very important for nowcasting and forecasting space weather models. We investigate the sensitivity of the two parameterizations of the radial diffusion of Brautigam and Albert [2000] and Ozeke et al. [2014] on long-term radiation belt modeling using the Versatile Electron Radiation Belt (VERB). Following Brautigam and Albert [2000] and Ozeke et al. [2014], we first perform 1-D radial diffusion simulations. Comparison of the simulation results with observations shows that the difference between simulations with either radial diffusion parameterization is small. To take into account effects of local acceleration and loss, we perform 3-D simulations, including pitch-angle, energy and mixed diffusion. We found that the results of 3-D simulations are even less sensitive to the choice of parameterization of radial diffusion rates than the results of 1-D simulations at various energies (from 0.59 to 1.80 MeV). This result demonstrates that the inclusion of local acceleration and pitch-angle diffusion can provide a negative feedback effect, such that the result is largely indistinguishable simulations conducted with different radial diffusion parameterizations. We also perform a number of sensitivity tests by multiplying radial diffusion rates by constant factors and show that such an approach leads to unrealistic predictions of radiation belt dynamics. References Brautigam, D. H., and J. M. Albert (2000), Radial diffusion analysis of outer radiation belt electrons during the October 9, 1990, magnetic storm, J. Geophys. Res., 105(A1), 291-309, doi:10.1029/1999ja900344. Ozeke, L. G., I. R. Mann, K. R. Murphy, I. Jonathan Rae, and D. K. Milling (2014), Analytic expressions for ULF wave radiation belt radial diffusion coefficients, J. Geophys. Res. [Space Phys.], 119(3), 1587-1605, doi:10.1002/2013JA019204.

The 557.7 and 297.2 nm lines of O(1S) in the atmospheres of the terrestrial planets

NASA Astrophysics Data System (ADS)

Slanger, Tom; Sharpee, Brian; Pejakovic, Dusan; Gattinger, Richard; Llewellyn, Edward J.; McDade, Ian; Siskind, David; Minschwaner, Kenneth

There are few examples of spectral features in nightglows or in auroras which can be used for relative intensity calibration from space, particularly over a broad wavelength region. One potential candidate is the atomic oxygen line pair at 297.2 nm (the trans-auroral line) and 557.7 nm (the green line). They share the common O(1 S0 ) upper level, and therefore the observed intensity ratio of the O(1 S0 -1 D2 ) and O(1 S0 -3 P1 ) lines has a value that is a quantum-mechanical constant, equal to the ratio of the respective transition probabilities. The recently-published figure of 9.3 ± 0.5 [Gattinger et al., 2009] for I557.7 /I297.2 confirms the earlier value of 9.8 ± 1.0 [Slanger et al., 2006] as well as a previous estimate of 9 [Sharp and Siskind,1989] (all expressed in photon units). Such good agreement suggests that this value can be used for a two-point calibration of orbiting spectrometers where both lines can be observed. O(1 S) emission is seen in the atmospheres of all three terrestrial planets -Venus, Earth, Mars. Comparison with theory is less satisfactory. The current ratio of these transition probabilities recommended by NIST is 16.7, based on numerous calculations. This emphasizes the uncertain-ties inherent in making calculations on strongly forbidden transitions. For the O(1 S) case, the transition to O(3 P) proceeds by spin-orbit interaction, whereas that to O(1 D) involves electric quadrupole interaction. References Gattinger, R.L., et al., Can. J. Phys. 87, 1133, 2009 Sharp, W.E. and D.E. Siskind, Geophys. Res. Lett. 16, 1453, 1989 Slanger, T.G., et al., J. Geophys. Res. 111, A12318, 2006

On the properties and limitations of magnetic reconnection in Hall MHD

NASA Astrophysics Data System (ADS)

Chacon, L.; Simakov, A. N.; Zocco, A.

2008-12-01

Magnetic reconnection is a key process in nature whereby magnetic energy is converted into kinetic and thermal energy. Magnetic reconnection fundamentally affects space, astrophysical, and laboratory plasmas, and usually happens on very fast time scales, possibly unrelated to underlying dissipation mechanisms. However, despite substantial theoretical progress in the understanding of fast reconnection (J. Birn et al., , J. Geophys. Res. 106, 3715, 2001). A fundamental analytical model capable of explaining these time scales has been lacking. Developing such a model is of the essence not only to further the basic understanding of reconnection, but also to provide resolution to controversies arising from numerical computations, which by necessity can only cover a limited region in parametric space. In this presentation, we will discuss a recently- developed analytical framework for describing the dynamics of a 2D diffusion region in Hall MHD. Equations controlling the diffusion region can be coupled to those modeling a macroscopic driver, thus providing a time- dependent description of the reconnection process (A. N. Simakov, L. Chacón, D. A. Knoll, Phys. Plasmas, 13, 082103, 2006). A steady-state analysis of the microscopic equations gives insight into the properties and limitations of the 2D reconnecting system. Despite the steady-state assumption, such insight has been shown to be applicable to predict maximum reconnection rates of highly dynamic systems.c,d,f Furthermore, we have found that the steady-state model adequately describes all regimes of interest of the ion inertial length di (A. N. Simakov and L. Chacón, Phys. Rev. Lett., accepted (2008)), recovering the resistive (Sweet-Parker) and electron MHD solutions in the appropriate limits (L. Chacón, A. N. Simakov, and A. Zocco, Phys. Rev. Lett. 99, 235001 (2007)). It also describes finite electron inertia effects (A. Zocco, L. Chacón, A. N. Simakov, "Electron inertia effects in 2D driven reconnection in electron MHD," Proc. of the Joint Varenna-Lausanne International Workshop on the Theory of Fusion Plasmas, Varenna, Italy, Aug. 25-29 (2008)). The model gives predictions for the dissipation region aspect ratio and the reconnection rate Ez in terms of dissipation and inertial parameters, and has been found to be in excellent agreement with non-linear simulations. It confirms a number of long-standing empirical results, and resolves several controversies. In particular, we find that both open X-point and elongated dissipation regions are possible, and that Ez depends strongly on di and on the length of the current sheet. Moreover, when applied to electron-positron plasmas, the model demonstrates that fast dispersive waves are not instrumental for fast reconnection (L. Chacón, A. N. Simakov, V. Lukin, and A. Zocco, Phys. Rev. Lett., 101, 025003, 2008). and that small-scale dissipation holds the key for the understanding of this phenomenon. The latter is a striking prediction, with important implications for the understanding of highly dynamic reconnection processes.

Anti-hepatocarcinoma effects of resveratrol nanoethosomes against human HepG2 cells

NASA Astrophysics Data System (ADS)

Meng, Xiang-Ping; Zhang, Zhen; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

2017-02-01

Hepatocarcinoma, a malignant cancer, threaten human life badly. It is a current issue to seek the effective natural remedy from plant to treat cancer due to the resistance of the advanced hepatocarcinoma to chemotherapy. Resveratrol (Res) has been widely investigated with its strong anti-tumor activity. However, its low oral bioavailability restricts its wide application. In this study, we prepared resveratrol nanoethosomes (ResN) via ethanol injection method. The in vitro anti-hepatocarcinoma effects of ResN relative to efficacy of bulk Res were evaluated on proliferation and apoptosis of human HepG2 cells. ResN were spherical vesicles and its particle diameter, zeta potential were (115.8 +/- 1.3) nm and (-12.8 +/- 1.9) mV, respectively. ResN exhibited significant inhibitory effects against human HepG2 cells by MTT assay, and the IC50 value was 49.2 μg/ml (105.4 μg/ml of Res bulk solution). By flow cytometry assay, there was an increase in G2/M phase cells treated with ResN. The results demonstrated ResN could effectively block the G2/M phase of HepG2 cells, which can also enhance the inhibitory effect of Res against HepG2 cells.

Green tea extract selectively targets nanomechanics of live metastatic cancer cells

NASA Astrophysics Data System (ADS)

Cross, Sarah E.; Jin, Yu-Sheng; Lu, Qing-Yi; Rao, JianYu; Gimzewski, James K.

2011-05-01

Green tea extract (GTE) is known to be a potential anticancer agent (Yang et al 2009 Nat. Rev. Cancer 9 429-39) with various biological activities (Lu et al 2005 Clin. Cancer Res. 11 1675-83 Yang et al 1998 Carcinogenesis 19 611-6) yet the precise mechanism of action is still unclear. The biomechanical response of GTE treated cells taken directly from patient's body samples was measured using atomic force microscopy (AFM) (Binnig et al 1986 Phys. Rev. Lett. 56 930). We found significant increase in stiffness of GTE treated metastatic tumor cells, with a resulting value similar to untreated normal mesothelial cells, whereas mesothelial cell stiffness after GTE treatment is unchanged. Immunofluorescence analysis showed an increase in cytoskeletal-F-actin in GTE treated tumor cells, suggesting GTE treated tumor cells display mechanical, structural and morphological features similar to normal cells, which appears to be mediated by annexin-I expression, as determined by siRNA analysis of an in vitro cell line model. Our data indicates that GTE selectively targets human metastatic cancer cells but not normal mesothelial cells, a finding that is significantly advantageous compared to conventional chemotherapy agents.

Galactic cosmic ray spectral index: the case of Forbush decreases of March 2012

NASA Astrophysics Data System (ADS)

Livada, M.; Mavromichalaki, H.; Plainaki, C.

2018-01-01

During the burst of solar activity in March 2012, close to the maximum of solar cycle 24, a number of X-class and M-class flares and halo CMEs with velocity up to 2684 km/s were recorded. During a relatively short period (7-21 March 2012) two Forbush decreases were registered in the ground-level neutron monitor data. In this work, after a short description of the solar and geomagnetic background of these Forbush decreases, we deduce the cosmic ray density and anisotropy variations based on the daily cosmic ray data of the neutron monitor network (http://www.nmdb.eu; http://cosray.phys.uoa.gr). Applying to our data two different coupling functions methods, the spectral index of these Forbush decreases was calculated following the technique of Wawrzynczak and Alania (Adv. Space Res. 45:622-631, 2010). We pointed out that the estimated values of the spectral index γ of these events are almost similar for both cases following the fluctuation of the Forbush decrease. The study and the calculation of the cosmic ray spectrum during such cosmic ray events are very important for Space Weather applications.

Nonvariational calculation of the relativistic, finite-size, and QED corrections for the 2 1S excited state of the helium atom

NASA Astrophysics Data System (ADS)

Haftel, M. I.; Mandelzweig, V. B.

1994-05-01

Relativistic and QED corrections are calculated by using a direct solution of the Schrödinger equation for the 2 1S excited state of the helium atom obtained with the correlation-function hyperspherical-harmonic method. Our extremely accurate nonvariational results for relativistic, QED, and finite-size corrections coincide exactly (up to 0.000 03 cm-1) with the values obtained in precision variational calculations of Drake [Nucl. Instrum. Methods Phys. Res. B 5, 2207 (1988)] and Baker, Hill, and Morgan [in Relativistic, Quantum Electrodynamic and Weak Interaction Effects in Atoms, edited by Walter Johnson, Peter Mohr, and Joseph Sucher, AIP Conf. Proc. No. 189 (AIP, New York, 1989), p. 123] for both infinite and finite nuclear masses. This confirms that a discrepancy of 0.0033 cm-1 between theory and experiment is not a result of an inaccuracy of variational wave functions, but is rooted in our inadequate knowledge of the QED operators. A better understanding of the different QED contributions to the operators (such as, for example, a more precise estimate of the Bethe logarithm) is therefore needed to explain the discrepancy.

Development of Wien filter for small ion gun of surface analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahng, Jungbae; Busan Center, Korea Basic Science Institute, Busan 609-735; Hong, Jonggi

The gas cluster ion beam (GCIB) and liquid metal ion beam have been studied in the context of ion beam usage for analytical equipment in applications such as X-ray photoelectron spectroscopy and secondary ion mass spectroscopy (SIMS). In particular, small ion sources are used for the secondary ion generation and ion etching. To set the context to this study, the SIMS project has been launched to develop ion-gun based analytical equipment for the Korea Basic Science Institute. The objective of the first stage of the project is the generation of argon beams with a GCIB system [A. Kirkpatrick, Nucl. Instrum.more » Methods Phys. Res., Sect. B 206, 830–837 (2003)] that consists of a nozzle, skimmer, ionizer, acceleration tube, separation system, transport system, and target. The Wien filter directs the selected cluster beam to the target system by exploiting the velocity difference of the generated particles from GCIB. In this paper, we present the theoretical modeling and three-dimensional electromagnetic analysis of the Wien filter, which can separate Ar{sup +}{sub 2500} clusters from Ar{sup +}{sub 2400} to Ar{sup +}{sub 2600} clusters with a 1-mm collimator.« less

Beyond detection: biological physics informing progression and treatment of cancer Beyond detection: biological physics informing progression and treatment of cancer

NASA Astrophysics Data System (ADS)

Newman, T. J.; Thompson, A. M.

2012-12-01

The full text of the Preface is given in the PDF file. References [1] Kaur P et al 2012 Phys. Biol. 9 065001 [2] Lobikin M et al 2012 Phys. Biol. 9 065002 [3] Tanner K 2012 Phys. Biol. 9 065003 [4] Liu S V et al 2012 Phys. Biol. 9 065004 [5] Liao D et al 2012 Phys. Biol. 9 065005 [6] Liao D et al 2012 Phys. Biol. 9 065006 [7] Orlando P A et al 2012 Phys. Biol. 9 065007

The BonaRes Centre - A virtual institute for soil research in the context of a sustainable bio-economy

NASA Astrophysics Data System (ADS)

Wollschläger, Ute; Helming, Katharina; Heinrich, Uwe; Bartke, Stephan; Kögel-Knabner, Ingrid; Russell, David; Eberhardt, Einar; Vogel, Hans-Jörg

2016-04-01

Fertile soils are central resources for the production of biomass and provision of food and energy. A growing world population and latest climate targets lead to an increasing demand for both, food and bio-energy, which require preserving and improving the long-term productivity of soils as a bio-economic resource. At the same time, other soil functions and ecosystem services need to be maintained. To render soil management sustainable, we need to establish a scientific knowledge base about complex soil system processes that allows for the development of model tools to quantitatively predict the impact of a multitude of management measures on soil functions. This, finally, will allow for the provision of site-specific options for sustainable soil management. To face this challenge, the German Federal Ministry of Education and Research recently launched the funding program "Soil as a Natural Resource for the Bio-Economy - BonaRes". In a joint effort, ten collaborative projects and the coordinating BonaRes Centre are engaged to close existing knowledge gaps for a profound and systemic understanding of soil functions and their sensitivity to soil management. This presentation provides an overview of the concept of the BonaRes Centre which is responsible for i) setting up a comprehensive data base for soil-related information, ii) the development of model tools aiming to estimate the impact of different management measures on soil functions, and iii) establishing a web-based portal providing decision support tools for a sustainable soil management. A specific focus of the presentation will be laid on the so-called "knowledge-portal" providing the infrastructure for a community effort towards a comprehensive meta-analysis on soil functions as a basis for future model developments.

Development of an enzyme-linked immunoelectrotransfer blot (EITB) assay using two baculovirus expressed recombinant antigens for diagnosis of Taenia solium taeniasis.

PubMed

Levine, Min Z; Lewis, Melissa M; Rodriquez, Silvia; Jimenez, Juan A; Khan, Azra; Lin, Sehching; Garcia, Hector H; Gonzales, Armando E; Gilman, Robert H; Tsang, Victor C W

2007-04-01

Taeniasis diagnosis is an important step in the control and elimination of both cysticercosis and taeniasis. We report the development of 2 serological taeniasis diagnostic tests using recombinant antigens rES33 and rES38 expressed by baculovirus in insect cells in an EITB format. In laboratory testing with defined sera from nonendemic areas, rES33 has a sensitivity of 98% (n = 167) and a specificity of 99% (n = 310) (J index: 0.97); rES38 has a sensitivity of 99% (n = 146) and a specificity of 97% (n = 275) (J index: 0.96). Independent field testing in Peru showed 97% (n = 203) of the taeniasis sera were positive with rES33, and 100% of the nontaeniasis sera (n = 272) were negative with rES33; 98% (n = 198) of taeniasis sera were positive with rES38, and 91% (n = 274) of the nontaeniasis sera were negative with rES38. Among the Peruvian sera tested, 17 of 26 Peruvian Taenia saginata sera were false positive with rES38 test. Both tests were also examined with cysticercosis sera, with a positive rate ranging from 21% to 46%. rES33 and rES38 tests offer sensitive and specific diagnosis of taeniasis and easy sample collection through finger sticks that can be used in large-scale studies. They are currently being used in cysticercosis elimination programs in Peru.

The Effects of Letter Spacing and Coloured Overlays on Reading Speed and Accuracy in Adult Dyslexia

ERIC Educational Resources Information Center

Sjoblom, Amanda M.; Eaton, Elizabeth; Stagg, Steven D.

2016-01-01

Background: Zorzi et al. (2012, Proc. Natl. Acad. Sci. U.S.A., 109, 11455) found evidence that extra-large letter spacing aids children with dyslexia, but the evidence for the coloured overlays is contradictory (e.g., Henderson et al., 2013, "J. Res. Special Educ. Needs," 13, 57; Wilkins, 2002, "Ophthalmic Physiol. Opt.," 22,…

Reading, Writing, and Math Self-Concept in Elementary School Children: Influence of Dimensional Comparison Processes

ERIC Educational Resources Information Center

Ehm, Jan-Henning; Lindberg, Sven; Hasselhorn, Marcus

2014-01-01

The internal/external (I/E) frame of reference model (Marsh, "Am Educ Res J" 23:129-149, 1986) conceptualizes students' self-concepts as being formed by dimensional as well as social comparison processes. In the present study, the I/E model was tested and extended in a sample of elementary school children. Core academic skills of…

Capturing and portraying science student teachers' pedagogical content knowledge through CoRe construction

NASA Astrophysics Data System (ADS)

Thongnoppakun, Warangkana; Yuenyong, Chokchai

2018-01-01

Pedagogical content knowledge (PCK) is an essential kind of knowledge that teacher have for teaching particular content to particular students for enhance students' understanding, therefore, teachers with adequate PCK can give content to their students in an understandable way rather than transfer subject matter knowledge to learner. This study explored science student teachers' PCK for teaching science using Content representation base methodology. Research participants were 68 4th year science student teachers from department of General Science, faculty of Education, Phuket Rajabhat University. PCK conceptualization for teaching science by Magnusson et al. (1999) was applied as a theoretical framework in this study. In this study, Content representation (CoRe) by Loughran et al. (2004) was employed as research methodology in the lesson preparation process. In addition, CoRe consisted of eight questions (CoRe prompts) that designed to elicit and portray teacher's PCK for teaching science. Data were collected from science student teachers' CoRes design for teaching a given topic and student grade. Science student teachers asked to create CoRes design for teaching in topic `Motion in one direction' for 7th grade student and further class discussion. Science student teachers mostly created a same group of science concepts according to subunits of school science textbook rather than planned and arranged content to support students' understanding. Furthermore, they described about the effect of student's prior knowledge and learning difficulties such as students' knowledge of Scalar and Vector quantity; and calculating skill. These responses portrayed science student teacher's knowledge of students' understanding of science and their content knowledge. However, they still have inadequate knowledge of instructional strategies and activities for enhance student learning. In summary, CoRes design can represented holistic overviews of science student teachers' PCK related to the teaching of a particular topic and also support them to gain more understanding about how to teach for understanding. Research implications are given for teacher education and educational research to offer a potential way to enhance science student teachers' PCK for teaching science and support their professional learning.

EDITORIAL: 'Best article' prize for the 5th anniversary of Environmental Research Letters 'Best article' prize for the 5th anniversary of Environmental Research Letters

NASA Astrophysics Data System (ADS)

Kammen, Dan; Wright, Guillaume

2011-12-01

To celebrate the 5th anniversary of Environmental Research Letters (ERL) the publishers of the journal, IOP Publishing, have awarded a prize for the five best articles published in ERL since the journal began in 2006. The procedure for deciding the winning articles was as thorough as possible to ensure that the most outstanding articles would win the prize. A shortlist of 25 nominated research articles, five for each year since ERL was launched, which were chosen based on a range of criteria including novelty, scientific impact, readership, broad appeal and wider media coverage, was selected. The ERL Editorial Board then assessed and rated these 25 articles in order to choose a winning article for each year. We would like to announce that the following articles have been awarded ERL's 5th anniversary best article prize: 2006/7 The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest Ilan Koren, Yoram J Kaufman, Richard Washington, Martin C Todd, Yinon Rudich, J Vanderlei Martins and Daniel Rosenfeld 2006 Environ. Res. Lett. 1 014005 2008 Causes and impacts of the 2005 Amazon drought Ning Zeng, Jin-Ho Yoon, Jose A Marengo, Ajit Subramaniam, Carlos A Nobre, Annarita Mariotti and J David Neelin 2008 Environ. Res. Lett. 3 014002 2009 How difficult is it to recover from dangerous levels of global warming? J A Lowe, C Huntingford, S C B Raper, C D Jones, S K Liddicoat and L K Gohar 2009 Environ. Res. Lett. 4 014012 2010 Is physical water scarcity a new phenomenon? Global assessment of water shortage over the last two millennia Matti Kummu, Philip J Ward, Hans de Moel and Olli Varis 2010 Environ. Res. Lett. 5 034006 2011 Implications of urban structure on carbon consumption in metropolitan areas Jukka Heinonen and Seppo Junnila 2011 Environ. Res. Lett. 6 014018 Our congratulations go to these authors. In recognition of their outstanding work, we are delighted to offer all of the authors of the winning articles free publication in the journal until the end of 2012. Of course all of the shortlisted papers were of great merit, and the full list of nominees can be found below (in alphabetical order). Nominees Achard F, DeFries R, Eva H, Hansen M, Mayaux P and Stibig H-J 2007 Environ. Res. Lett. 2 045022 Baccini A, Laporte N, Goetz S J, Sun M and Dong H 2008 Environ. Res. Lett. 3 045011 Barona E, Ramankutty N, Hyman G and Coomes O T 2010 Environ. Res. Lett. 5 024002 Charpentier A D, Bergerson J A and MacLean H L 2009 Environ. Res. Lett. 4 014005 Chester M V and Horvath A 2009 Environ. Res. Lett. 4 024008 Cooley S R and Doney S C 2009 Environ. Res. Lett. 4 024007 Diffenbaugh N S, White M A, Jones G V and Ashfaq M 2011 Environ. Res. Lett. 6 024024 Farrell A E and Brandt A R 2006 Environ. Res. Lett. 1 014004 Graham W M, Condon R H, Carmichael R H, D'Ambra I, Patterson H K, Linn L J and Hernandez F J Jr 2010 Environ. Res. Lett. 5 045301 Hansen J E 2007 Environ. Res. Lett. 2 024002 Heinonen J and Junnila S 2011 Environ. Res. Lett. 6 014018 Jackson R B et al 2008 Environ. Res. Lett. 3 044006 Jiang M, Michael Griffin W, Hendrickson C, Jaramillo P, VanBriesen J and Venkatesh A 2011 Environ. Res. Lett. 6 034014 Koren I, Kaufman Y J, Washington R, Todd M C, Rudich Y, Martins J V and Rosenfeld D 2006 Environ. Res. Lett. 1 014005 Kummu M, Ward P J, de Moel H and Varis O 2010 Environ. Res. Lett. 5 034006 Lau W K M, Kim M-K, Kim K-M and Lee W-S 2010 Environ. Res. Lett. 5 025204 Lindeboom H J et al 2011 Environ. Res. Lett. 6 035101 Lowe J A, Huntingford C, Raper S C B, Jones C D, Liddicoat S K and Gohar L K 2009 Environ. Res. Lett. 4 014012 Möhler O, Benz S, Saathoff H, Schnaiter M, Wagner R, Schneider J, Walter S, Ebert V and Wagner S 2008 Environ. Res. Lett. 3 025007 Menon S, Akbari H, Mahanama S, Sednev I and Levinson R 2010 Environ. Res. Lett. 5 014005 Schneider A, Friedl M A and Potere D 2009 Environ. Res. Lett. 4 044003 Sloan T and Wolfendale A W 2008 Environ. Res. Lett. 3 024001 Tedesco M, Fettweis X, van den Broeke M R, van de Wal R S W, Smeets C J P P, van de Berg W J, Serreze M C and Box J E 2011 Environ. Res. Lett. 6 014005 Wang M, Wu M and Huo H 2007 Environ. Res. Lett. 2 024001 Zeng N, Yoon J H, Marengo J A, Subramaniam A, Nobre C A, Mariotti A and Neelin J D 2008 Environ. Res. Lett. 3 014002

Revisited comparison of thermal instability theory with MARFE density limit experiment in TEXTOR.

NASA Astrophysics Data System (ADS)

Kelly, Frederick

2006-03-01

Density limit shots in TEXTOR [Tokamak EXperiment for Technology Oriented Research] that ended in MARFE [Multifaceted Asymmetric Radiation From the Edge] are analyzed by several thermal instability theories^1-7 with convective effects included. ^1W. M. Stacey, Phys. Plasmas 3, 2673 (1996); Phys. Plasmas 3, 3032 (1996); Phys. Plasmas 4, 134 (1997); Phys. Plasmas 4, 242 (1997). ^2W. M. Stacey, Plasma Phys. Contr. Fusion 39, 1245 (1997). ^3W. M. Stacey, Fusion Technol. 36, 38 (1999).^ ^4W. M. Stacey, Phys. Plasmas 7, 3464 (2000). ^5F. A. Kelly, W. M. Stacey, J. Rapp and M. Brix, Phys. Plasmas 8, 3382 (2001). ^6M. Z. Tokar and F. A. Kelly, Phys. Plasmas 10, 4378 (2003). ^7M. Z. Tokar, F. A. Kelly and X. Loozen, Phys. Plasmas 12, 052510 (2005).

Regional Emphysema Score Predicting Overall Survival, Quality of Life and Pulmonary Function Recovery in Early-stage Lung Cancer Patients

PubMed Central

Dai, Jie; Liu, Ming; Swensen, Stephen J.; Stoddard, Shawn M.; Wampfler, Jason A.; Limper, Andrew H.; Jiang, Gening; Yang, Ping

2017-01-01

Introduction Pulmonary emphysema is a common comorbidity in lung cancer, but its role in tumor prognosis remains obscure. Our aim was to evaluate the impact of the regional emphysema score (RES) on patient’s overall survival, quality of life (QOL), and pulmonary function recovery in stage I–II lung cancer. Methods Between 1997 and 2009, 1,073 patients were identified and divided into two surgical groups (cancer in emphysematous [group 1, n=565] and non-emphysematous [group 2, n=435] region) and one non-surgical group (group 3, n=73). RES was derived from the emphysematous region and categorized into mild (≤5%), moderate (6–24%) and severe (25–60%). Results In group 1, patients with moderate and severe RES experienced slight decreases in postoperative FEV1, but increases in FEV1/FVC, compared to those with mild RES (p<0.01); however, this correlation was not observed in group 2. Post-treatment QOL was lower in patients with greater RES in all groups mainly due to dyspnea (p<0.05). Cox-regression analysis revealed that patients with higher RES had a significantly poorer survival in both surgical groups, with adjusted HRs of 1.41 and 1.43 for moderate RES and 1.63 and 2.04 for severe RES, respectively; however, this association was insignificant in the non-surgical group (adjusted HR of 0.99 for moderate/severe RES). Conclusions In surgically-treated patients with cancer in emphysematous region, RES is associated with postoperative changes in lung function. RES is also predictive of post-treatment QOL related to dyspnea in early-stage lung cancer. In both surgical groups, RES is an independent predictor of survival. PMID:28126539

Factors and trade-offs with rehabilitation effectiveness and efficiency in newly disabled older persons.

PubMed

Chow, Patsy; Chen, Cynthia; Cheong, Angela; Fong, Ngan Phoon; Chan, Kin Ming; Tan, Boon Yeow; Menon, Edward; Ee, Chye Hua; Lee, Kok Keng; Koh, David; Koh, Gerald C

2014-08-01

To determine the factors for rehabilitation effectiveness (REs) and rehabilitation efficiency (REy) among newly disabled older persons and if there is any trade-off between REs and REy. Retrospective cohort study. Rehabilitation hospitals. Patients (N=8828) aged ≥65 years admitted for inpatient rehabilitation from 1996 to 2005. Not applicable. Independent factors affecting REs and REy were determined. The median rank ratios of REs to REy for each admission Barthel Index (BI) unit and number of days of stay were generated. The ideal ranges of admission BI score and length of stay (LOS) that corresponded to the REs to REy median rank ratio of 1 (both REs and REy optimized) were identified. Factors associated with poorer REs and REy were older age, Malay ethnicity, delayed admission, admission diagnosis of amputation, and comorbidities of dementia and stroke. An increase of 10 in admission BI score was associated with an increase of 3.47% in REs but a decrease of 1.1 per 30 days in REy; and an increase in LOS of 2.7 days was associated with an increase of 28% in REs but a decrease of 5.2 per 30 days in REy. A trade-off relation between REs and REy with respect to admission functional status and LOS was observed. The range, which optimized both REs and REy, was 50 to 59 units for admission BI score and 37 to 46 days for LOS. There are trade-offs between REs and REy with respect to admission functional status and LOS. Clinicians, policymakers, patients, and other stakeholders should be aware of such trade-offs when they make joint policy decisions about rehabilitation services. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Best Practices in Physics Program Assessment: Should APS Provide Accreditation Standards for Physics?

NASA Astrophysics Data System (ADS)

Hodapp, Theodore

The Phys21 report, ``Preparing Physics Students for 21st Century Careers,'' provides guidance for physics programs to improve their degree programs to make them more relevant for student career choices. Undertaking such changes and assessing impact varies widely by institution, with many departments inventing assessments with each periodic departmental or programmatic review. American Physical Society has embarked on a process to integrate information from Phys21, the results of other national studies, and educational research outcomes to generate a best-practices guide to help physics departments conduct program review, assessment, and improvement. It is anticipated that departments will be able to use this document to help with their role in university-level accreditation, and in making the case for improvements to departmental programs. Accreditation of physics programs could stem from such a document, and I will discuss some of the thinking of the APS Committee on Education in creating this guide, and how they are advising APS to move forward in the higher education landscape that is increasingly subject to standards-based evaluations. I will describe plans for the design, review, and dissemination of this guide, and how faculty can provide input into its development. This material is based upon work supported by the National Science Foundation under Grant No. 1540570. Opinions expressed do not necessarily reflect those of the NSF.

Obliquely Propagating Waves in Bi-Kappa Plasmas

NASA Astrophysics Data System (ADS)

Gaelzer, R.; Ziebell, L. F.; Meneses, A. R.

2016-12-01

The effects of kappa velocity distribution functions (VDFs) have been the subjectof intense research. Such functions have beenfound to provide a better fitting to the VDFs measured by spacecraftin the solar wind. An anisotropic VDF contains free energy that can excite wavesin the plasma. The induced turbulence also determines the observed shape of the VDF.The general treatment for waves excited by (bi-)Maxwellian plasmas is well-established.However, for kappa distributions (isotropic or anisotropic), the majority of the studieswere restricted to the limiting cases of purely parallel or perpendicular propagation.Contributions to the general case of obliquely-propagating waves have been scarcely reported.The absence of a general treatment prevents a complete analysis of the wave-particle interactionin kappa plasmas, since some instabilities can operate both in the parallel and oblique directions.A series of papers published by the authors begin to remedy this situation. In a first work [1],we have obtained the dielectric tensor and dispersion relations for quasi-perpendicular dispersive Alfvén waves resulting from a kappa VDF. This approach was later generalized by [2],where the formalism was extended to the general case of electrostatic/electromagnetic waves propagatingin an isotropic kappa plasma in any frequency range and for arbitrary angles.In the present work [3], we generalize even further the formalism by the derivation of thegeneral dielectric tensor of an anisotropic bi-kappa plasma. We present the state-of-the-art of theformalism and show how it enables a systematic study of waves and instabilities propagating inarbitrary directions and frequencies in a bi-kappa plasma.[1] R. Gaelzer, L. F. Ziebell, J. Geophys. Res. 119, 9334 (2014), doi: 10.1002/2014JA020667.[2] R. Gaelzer, L. F. Ziebell, Phys. Plasmas 23, 022110 (2016), doi: 10.1063/1.4941260.[3] R. Gaelzer et al., Phys. Plasmas 23, 062108 (2016), doi: 10.1063/1.4953430.

On the Distribution of Earthquake Interevent Times and the Impact of Spatial Scale

NASA Astrophysics Data System (ADS)

Hristopulos, Dionissios

2013-04-01

The distribution of earthquake interevent times is a subject that has attracted much attention in the statistical physics literature [1-3]. A recent paper proposes that the distribution of earthquake interevent times follows from the the interplay of the crustal strength distribution and the loading function (stress versus time) of the Earth's crust locally [4]. It was also shown that the Weibull distribution describes earthquake interevent times provided that the crustal strength also follows the Weibull distribution and that the loading function follows a power-law during the loading cycle. I will discuss the implications of this work and will present supporting evidence based on the analysis of data from seismic catalogs. I will also discuss the theoretical evidence in support of the Weibull distribution based on models of statistical physics [5]. Since other-than-Weibull interevent times distributions are not excluded in [4], I will illustrate the use of the Kolmogorov-Smirnov test in order to determine which probability distributions are not rejected by the data. Finally, we propose a modification of the Weibull distribution if the size of the system under investigation (i.e., the area over which the earthquake activity occurs) is finite with respect to a critical link size. keywords: hypothesis testing, modified Weibull, hazard rate, finite size References [1] Corral, A., 2004. Long-term clustering, scaling, and universality in the temporal occurrence of earthquakes, Phys. Rev. Lett., 9210) art. no. 108501. [2] Saichev, A., Sornette, D. 2007. Theory of earthquake recurrence times, J. Geophys. Res., Ser. B 112, B04313/1-26. [3] Touati, S., Naylor, M., Main, I.G., 2009. Origin and nonuniversality of the earthquake interevent time distribution Phys. Rev. Lett., 102 (16), art. no. 168501. [4] Hristopulos, D.T., 2003. Spartan Gibbs random field models for geostatistical applications, SIAM Jour. Sci. Comput., 24, 2125-2162. [5] I. Eliazar and J. Klafter, 2006. Growth-collapse and decay-surge evolutions, and geometric Langevin equations, Physica A, 367, 106 - 128.

Effect of texture on rheological properties: the case of ɛ-Fe (Invited)

NASA Astrophysics Data System (ADS)

Merkel, S.; Gruson, M.; Tomé, C. N.; Nishiyama, N.; Wang, Y.

2009-12-01

Lattice preferred orientations (LPO) are known to affect the physical properties of materials. However, in most high pressure deformation experiments, LPO are ignored when interpreting the measured stress-strain curves. In addition, stress measurements in those experiments are complicated by the effect of plastic deformation on the measured lattice strains(1). Here, we present a new interpretation of the results obtained on hcp-iron at up to 19 GPa and 600 K in the deformation-DIA(2). In those experiments, five independent stress-strain curves were obtained on axial shortening with a ductile behavior of the sample for all. Stress were studied using results of monochromatic X-ray diffraction and the elastic theory of lattice strains(3). However, measured stresses were inconsistent with a change of behavior after 4% axial strain, particularly for strains measured on the 0002 line. We use elasto-plastic self consistent modeling(1) to show that this change of behavior is due to the evolution of LPO in the sample. With compression, 10-10 planes in hcp-iron align parallel to the compression direction and this affects the rheological behavior of the sample, which can not be summarized in a simple average law. We will also discuss the implication of those results for the extraction of polycrystalline rheological properties for materials with non-random lattice preferred orientations and how this could affect our understanding of the Earth deep interior. 1- S. Merkel, C.N. Tomé, H.-R Wenk, A modeling analysis of the influence of plasticity on high pressure deformation of hcp-Co, Phys. Rev. B, 79, 064110 (2009) 2- N. Nishiyama, Y. Wang, M. L. Rivers, S. R. Sutton, D. Cookson, Rheology of e-iron up to 19 GPa and 600 K in the D-DIA, Geophys. Res. Lett., 34, L23304 (2007) 3- A. K. Singh, C. Balasingh, H. K. Mao, R. J. Hemley, J. Shu, Analysis of lattice strains measured under non-hydrostatic pressure, J. Appl. Phys., 83, 7567-7575 (1998)

Randomized clinical study assessing two membranes for guided bone regeneration of peri-implant bone defects: clinical and histological outcomes at 6 months.

PubMed

Naenni, Nadja; Schneider, David; Jung, Ronald E; Hüsler, Jürg; Hämmerle, Christoph H F; Thoma, Daniel S

2017-10-01

To test whether or not one of two membranes is superior for peri-implant-guided bone regeneration in terms of clinical and histologic outcomes. In 27 patients, 27 two-piece dental implants were placed in single-tooth gaps in the esthetic area. Buccal dehiscence and/or fenestration-type defects were regenerated using demineralized bovine bone mineral and randomly covered with either a resorbable membrane (RES) or a titanium-reinforced non-resorbable membrane (N-RES). Clinical measurements included vertical defect resolution and the horizontal thickness of regenerated bone at implant placement and at 6 months. Statistics were performed by means of nonparametric testing. The remaining mean vertical defect measured 4 mm (±2.07) (RES) and 2.36 mm (±2.09) (N-RES) (P = 0.044) at baseline and 0.77 mm (±0.85) (RES) and 0.21 mm (±0.80) (N-RES) (P = 0.021) at re-entry. This translated into a defect resolution of 85% (RES) and 90.7% (N-RES) (P = 0.10). The horizontal thickness after augmentation measured 3.46 mm (±0.52) (RES) and 2.82 mm (±0.50) (N-RES) (P = 0.004). The mean loss in horizontal thickness from baseline to re-entry measured 2.23 mm (SD ±1.21) (RES) and 0.14 mm (±0.79) (N-RES) (P = 0.017). The horizontal changes in thickness at the implant shoulder level were statistically significant between the groups (P = 0.0001). Both treatment modalities were clinically effective in regenerating bone as demonstrated by a similar horizontal thickness and vertical defect fill at 6 months. The N-RES group exhibited significantly less horizontal bone thickness reduction from baseline to follow-up. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Soil as a Sustainable Resource for the Bioeconomy - BonaRes

NASA Astrophysics Data System (ADS)

Wollschläger, Ute; Amelung, Wulf; Brüggemann, Nicolas; Brunotte, Joachim; Gebbers, Robin; Grosch, Rita; Heinrich, Uwe; Helming, Katharina; Kiese, Ralf; Leinweber, Peter; Reinhold-Hurek, Barbara; Veldkamp, Edzo; Vogel, Hans-Jörg; Winkelmann, Traud

2017-04-01

Fertile soils are a fundamental resource for the production of biomass and provision of food and energy. A growing world population and latest climate targets lead to an increasing demand for bio-based products which require preserving and - ideally - improving the long-term productivity of soils as a bio-economic resource. At the same time, other soil functions and ecosystem services need to be maintained: filter for clean water, carbon sequestration, provision and recycling of nutrients, and habitat for biological activity. All these soil functions result from the interaction of a multitude of physical, chemical and biological processes which are insufficiently understood. In addition, we lack understanding about the interplay between the socio-economic system and the soil system and how soil functions benefit human wellbeing, including SDGs. However, a solid and integrated assessment of soil quality requires the consideration of the ensemble of soil functions and its relation to soil management. To make soil management sustainable, we need to establish a scientific knowledge base of complex soil system processes that allows for developing models and tools to quantitatively predict the impact of a multitude of management measures on soil functions. This will finally allow for the provision of options for a site-specific, sustainable soil management. To face this challenge, the German Federal Ministry of Education and Research (BMBF) recently launched the funding program "Soil as a Sustainable Resource for the Bioeconomy - BonaRes". In a joint effort, ten collaborative projects and the coordinating BonaRes Centre are engaged to close existing knowledge gaps for a profound and systemic assessment and understanding of soil functions and their sensitivity to soil management. In BonaRes, the complete process chain of sustainable soil use in the context of a sustainable bio-economy is being addressed: from understanding of soil processes using state-of the art and novel measurement and modelling techniques towards soil functions and ecosystem services driving the development of assessment and decision support tools for a sustainable soil management. To this end, soil scientists and researchers from several other disciplines including social sciences are collaborating closely. Besides a better understanding of fundamental soil processes from each of the collaborative projects and the development of novel measurement techniques and models, the outcome of the joint BonaRes programme will be a web-based portal (www.bonares.de) providing information, knowledge, models, a data repository with doi-referenced, internationally available, open soil data from the BonaRes funding initiative and beyond, as well as decision support options for a sustainable soil management. This presentation will provide an overview about the BonaRes funding initiative and the research conducted therein.

Misconceptions indeed

NASA Astrophysics Data System (ADS)

Schumayer, D.; Scott, T. F.

2016-11-01

In a recent article Fotou and Abrahams (2016 Phys. Educ. 51 044003) described a study which investigated how students approach novel situations and whether their reasoning can be understood as theory-like misconceptions or phenomenological primitives. Two exemplary questions polling students’ concepts of gravity were presented in their article. Although we find the authors’ motivation and approach interesting we also raise concerns about one of these problems.

Projectile Motion on an Inclined Misty Surface: II. Scoring a Goal

ERIC Educational Resources Information Center

Foong, S. K.; Lim, C. C.; Kuppan, L.

2009-01-01

Feedback on part I of this series (Ho "et al" 2009 "Phys. Educ." 44 253) motivated us to make hitting the target more interesting with a simple innovation: changing the target to a ring shaped hoop or goalpost and shooting for it in the "air", as if playing basketball on the inclined plane. We discuss in detail the…

Newton's Laws: A Very Persistent Consistency

ERIC Educational Resources Information Center

Viennot, Laurence

2012-01-01

This note is a response to a recent paper by McClelland (2011 "Phys. Educ." 46 469-471). The situation of a person who is walking horizontally along the ground is examined, and the statement "The person is accelerated by a net force from the Earth" is considered invalid. A key point in McClelland's analysis is his claim that: "The force…

A Teacher's Guide to Including Students with Disabilities in General Physical Education, Third Edition

ERIC Educational Resources Information Center

Block, Martin E.

2007-01-01

This book, provides a comprehensive guide to making phys. ed. inclusion work for students of all ages. In this new edition of the trusted bestseller, renowned expert Martin E. Block and a select group of highly respected contributors provide: (1) new information reflecting all the latest updates to IDEA, other disability-related legislation, and…

Self-Nanoemulsifying Drug Delivery System for Resveratrol: Enhanced Oral Bioavailability and Reduced Physical Fatigue in Rats

PubMed Central

Yen, Ching-Chi; Hsu, Mei-Chich; Wu, Yu-Tse

2017-01-01

Resveratrol (RES), a natural polyphenolic compound, exerts anti-fatigue activity, but its administration is complicated by its low water solubility. To improve RES bioavailability, this study developed a self-nanoemulsifying drug delivery system (SNEDDS) for RES and evaluated its anti-fatigue activity and rat exercise performance by measuring fatigue-related parameters, namely lactate, ammonia, plasma creatinine phosphokinase, and glucose levels and the swimming time to exhaustion. Through solubility and emulsification testing, the optimized SNEDDS composed of Capryol 90, Cremophor EL, and Tween 20 was developed; the average particle size in this formulation, which had favorable self-emulsification ability, was approximately 41.3 ± 4.1 nm. Pharmacokinetic studies revealed that the oral bioavailability of the optimized RES-SNEDDS increased by 3.2-fold compared with that of the unformulated RES-solution. Pretreatment using the RES-SNEDDS before exercise accelerated the recovery of lactate after exercise; compared with the vehicle group, the plasma ammonia level in the RES-SNEDDS group significantly decreased by 65.4%, whereas the glucose level significantly increased by approximately 1.8-fold. Moreover, the swimming time to exhaustion increased by 2.1- and 1.8-fold, respectively, compared with the vehicle and RES-solution pretreatment groups. Therefore, the developed RES-SNEDDS not only enhances the oral bioavailability of RES but may also exert anti-fatigue pharmacological effect. PMID:28841149

Resveratrol and its combination with α-tocopherol mediate salt adaptation in citrus seedlings.

PubMed

Kostopoulou, Zacharoula; Therios, Ioannis; Molassiotis, Athanassios

2014-05-01

Resveratrol, a phytoalexin found in red wine, has the potential to impact a variety of human diseases but its function in plants exposed to stressful conditions is still unknown. In the present study the effect of exogenous application of resveratrol (Res), α-tocopherol (α-Toc) and their combination (Res+α-Toc) in salt adaptation of citrus seedlings was investigated. It was found that Res, α-Toc or Res+α-Toc treatments reduced NaCl-derived membrane permeability (EL), lipid peroxidation (MDA) and pigments degradation, whereas companied Res and α-Toc application also reduced H2O2 accumulation in leaves and restored the reduction of photosynthesis induced by NaCl. Application of Res under salinity retained Cl- in roots while Res+α-Toc reduced the translocation of Na+ and Cl- to leaves. Carbohydrates and proline, phenols, total ascorbic acid and glutathione were remarkably affected by NaCl as well as by chemical treatments in leaves and roots of citrus. NaCl treatment increased the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), glutathione reductase (GR), polyphenol oxidase (PPO) in leaves while SOD and POD activities were decreased in roots by this treatment. Also, Res, α-Toc or Res+α-Toc treatments displayed tissue specific activation or deactivation of the antioxidant enzymes. Overall, this work revealed a new functional role of Res in plants and provided evidence that the interplay of between Res and α-Toc is involved in salinity adaptation. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Series of (2+1)-dimensional stable self-dual interacting conformal field theories

NASA Astrophysics Data System (ADS)

Cheng, Meng; Xu, Cenke

2016-12-01

Using the duality between seemingly different (2+1)-dimensional [(2 +1 )d ] conformal field theories (CFT) proposed recently [D. T. Son, Phys. Rev. X 5, 031027 (2015), 10.1103/PhysRevX.5.031027; M. A. Metlitski and A. Vishwanath, Phys. Rev. B 93, 245151 (2016), 10.1103/PhysRevB.93.245151; C. Wang and T. Senthil, Phys. Rev. X 6, 011034 (2015), 10.1103/PhysRevX.6.011034; C. Wang and T. Senthil, Phys. Rev. X 5, 041031 (2015), 10.1103/PhysRevX.5.041031; C. Wang and T. Senthil, Phys. Rev. B 93, 085110 (2016), 10.1103/PhysRevB.93.085110; C. Xu and Y.-Z. You, Phys. Rev. B 92, 220416 (2015), 10.1103/PhysRevB.92.220416; D. F. Mross et al., Phys. Rev. Lett. 117, 016802 (2016), 10.1103/PhysRevLett.117.016802; A. Karch and D. Tong, arXiv:1606.01893; N. Seiberg et al., arXiv:1606.01989; P.-S. Hsin and N. Seiberg, arXiv:1607.07457], we study a series of (2 +1 )d stable self-dual interacting CFTs. These CFTs can be realized (for instance) on the boundary of the 3 d bosonic topological insulator protected by U(1) and time-reversal symmetry (T ), and they remain stable as long as these symmetries are preserved. When realized as a boundary system, these CFTs can be driven into anomalous fractional quantum Hall states once T is broken. We demonstrate that the newly proposed dualities allow us to study these CFTs quantitatively through a controlled calculation, without relying on a large flavor number of matter fields. We also propose a numerical test for our results, which would provide strong evidence for the originally proposed duality between Dirac fermion and QED.

Tests of Sunspot Number Sequences: 4. Discontinuities Around 1946 in Various Sunspot Number and Sunspot-Group-Number Reconstructions

NASA Astrophysics Data System (ADS)

Lockwood, M.; Owens, M. J.; Barnard, L.

2016-11-01

We use five test data series to search for, and quantify, putative discontinuities around 1946 in five different annual-mean sunspot-number or sunspot-group-number data sequences. The data series tested are the original and new versions of the Wolf/Zürich/International sunspot number composite [R_{{ISNv1}} and R_{{ISNv2}}] (respectively Clette et al. in Adv. Space Res. 40, 919, 2007 and Clette et al. in The Solar Activity Cycle 35, Springer, New York, 2015); the corrected version of R ISNv1 proposed by Lockwood, Owens, and Barnard ( J. Geophys. Res. 119, 5193, 2014a) [R C]; the new "backbone" group-number composite proposed by Svalgaard and Schatten ( Solar Phys. 291, 2016) [R_{{BB}}]; and the new group-number composite derived by Usoskin et al. ( Solar Phys. 291, 2016) [R_{{UEA}}]. The test data series used are the group-number [NG] and total sunspot area [A G] from the Royal Observatory, Greenwich/Royal Greenwich Observatory (RGO) photoheliographic data; the Ca K index from the recent re-analysis of Mount Wilson Observatory (MWO) spectroheliograms in the Calcium ii K ion line; the sunspot-group-number from the MWO sunspot drawings [N_{{MWO}}]; and the dayside ionospheric F2-region critical frequencies measured by the Slough ionosonde [foF2]. These test data all vary in close association with sunspot numbers, in some cases non-linearly. The tests are carried out using both the before-and-after fit-residual comparison method and the correlation method of Lockwood, Owens, and Barnard, applied to annual mean data for intervals iterated to minimise errors and to eliminate uncertainties associated with the precise date of the putative discontinuity. It is not assumed that the correction required is by a constant factor, nor even linear in sunspot number. It is shown that a non-linear correction is required by RC, R_{BB}, and R_{{ISNv1}}, but not by R_{{ISNv2}} or R_{{UEA}}. The five test datasets give very similar results in all cases. By multiplying the probability distribution functions together, we obtain the optimum correction for each sunspot dataset that must be applied to pre-discontinuity data to make them consistent with the post-discontinuity data. It is shown that, on average, values for 1932 - 1943 are too low (relative to later values) by about 12.3 % for R_{{ISNv1}} but are too high for R_{{ISNv2}} and R_{BB} by 3.8 % and 5.2 %, respectively. The correction that was applied to generate RC from R ISNv1 reduces this average factor to 0.5 % but does not remove the non-linear variation with the test data, and other errors remain uncorrected. A valuable test of the procedures used is provided by R_{{UEA}}, which is identical to the RGO NG values over the interval employed.

Relations between overturning length scales at the Spanish planetary boundary layer

NASA Astrophysics Data System (ADS)

López, Pilar; Cano, José L.

2016-04-01

We analyze the behavior of the maximum Thorpe displacement (dT)max and the Thorpe scale LTat the atmospheric boundary layer (ABL), extending previous research with new data and improving our studies related to the novel use of the Thorpe method applied to ABL. The maximum Thorpe displacements vary between -900 m and 950 m for the different field campaigns. The maximum Thorpe displacement is always greater under convective conditions than under stable ones, independently of its sign. The Thorpe scale LT ranges between 0.2 m and 680 m for the different data sets which cover different stratified mixing conditions (turbulence shear-driven and convective regions). The Thorpe scale does not exceed several tens of meters under stable and neutral stratification conditions related to instantaneous density gradients. In contrast, under convective conditions, Thorpe scales are relatively large, they exceed hundreds of meters which may be related to convective bursts. We analyze the relation between (dT)max and the Thorpe scale LT and we deduce that they verify a power law. We also deduce that there is a difference in exponents of the power laws for convective conditions and shear-driven conditions. These different power laws could identify overturns created under different mechanisms. References Cuxart, J., Yagüe, C., Morales, G., Terradellas, E., Orbe, J., Calvo, J., Fernández, A., Soler, M., Infante, C., Buenestado, P., Espinalt, Joergensen, H., Rees, J., Vilà, J., Redondo, J., Cantalapiedra, I. and Conangla, L.: Stable atmospheric boundary-layer experiment in Spain (Sables 98). A report, Boundary-Layer Meteorology, 96, 337-370, 2000. Dillon, T. M.: Vertical Overturns: A Comparison of Thorpe and Ozmidov Length Scales, J. Geophys. Res., 87(C12), 9601-9613, 1982. Itsweire, E. C.: Measurements of vertical overturns in stably stratified turbulent flow, Phys. Fluids, 27(4), 764-766, 1984. Kitade, Y., Matsuyama, M. and Yoshida, J.: Distribution of overturn induced by internal tides and Thorpe scale in Uchiura Bay, Journal of Oceanography, 59, 845-850, 2003. López P., Cano J. L., Cano D. and Tijera M.: Thorpe method applied to planetary boundary layer data, Il Nuovo Cimento, 31C(5-6), 881-892, 2008. DOI: 10.1393/ncc/i2009-10338-3. Lorke A. and Wüest A.: Probability density of displacement and overturning length scales under diverse stratification, J. Geophys. Res., 107 (C12), 3214-3225, 2002. Piera, J., Roget, E. and Catalan, J.: Turbulent patch identification in microstructure profiles: a method based on wavelet denoising and Thorpe displacement analysis, J. Atmospheric and Oceanic Technology, 19, 1390-1402, 2002. Piera, J.: Signal processing of microstructure profiles: integrating turbulent spatial scales in aquatic ecological modelling, Ph. D. Thesis, Gerona University, Spain, 2004. Smyth, W. D. and Moum, J. N.: Length scales of turbulence in stably stratified mixing layers, Phys. Fluids., 12, 1327-1342, 2000. Thorpe, S.A.: Turbulence and Mixing in a Scottish Loch, Philos. Trans. R. Soc. London (Ser. A), 286(1334), 125-18, 1977.

Special issue: diagnostics of atmospheric pressure microplasmas

NASA Astrophysics Data System (ADS)

Bruggeman, Peter; Czarnetzki, Uwe; Tachibana, Kunihide

2013-11-01

In recent decades, a strong revival of non-equilibrium atmospheric pressure plasma studies has developed in the form of microplasmas. Microplasmas have typical scales of 1 mm or less and offer a very exciting research direction in the field of plasma science and technology as the discharge physics can be considerably different due to high collisionality and the importance of plasma-surface interaction. These high-pressure small-scale plasmas have a diverse range of physical and chemical properties. This diversity coincides with various applications including light/UV sources [1], material processing [2], chemical analysis [3], material synthesis [4], electromagnetics [5], combustion [6] and even medicine [7]. At atmospheric pressure, large scale plasmas have the tendency to become unstable due to the high collision rates leading to enhanced heating and ionization compared to their low-pressure counterparts. As low-pressure plasmas typically operate in reactors with sizes of tens of centimetres, scaling up the pressure to atmospheric pressure the size of the plasma reduces to typical sizes below 1 mm. A natural approach of stabilizing atmospheric pressure plasmas is thus the use of microelectrode geometries. Traditionally microplasmas have been produced in confined geometries which allow one to stabilize dc excited discharges. This stabilization is intrinsically connected to the large surface-to-volume ratio which enhances heat transfer and losses of charged and excited species to the walls. Currently challenging boundaries are pushed by producing microcavity geometries with dimensions of the order of 1 µm [8]. The subject of this special issue, diagnostics of microplasmas, is motivated by the many challenges in microplasma diagnostics in view of the complex chemistry and strong spatial (and even temporal) gradients of species densities and plasma properties. Atmospheric pressure plasmas have a very long history dating back more than 100 years, with early work of, e.g. Werner von Siemens [9], who studied a dielectric barrier discharge (DBD) in the context of ozone generation. DBD discharges often consist of numerous filamentary discharges which are inherently transient in nature and with a characteristic size similar to the dimensions of microplasmas. Several groups are investigating the stabilization of such plasma filaments to perform temporal and spatial resolved diagnostics. To this end and due to the many similar challenges for diagnostics, this type of discharge is also included in this special issue. Research on microplasmas is performed in many groups spread all over the world, and a biannual workshop is devoted to the topic. The 7th edition of this International Workshop on Microplasmas was held in Beijing in May 2013. Large research programs consisting of clusters of research labs such as in Japan, Germany, France and the USA have been producing a wealth of information available in the literature. As the editors of this special issue, we are very pleased to have attracted a collection of excellent papers from leading experts in the field covering most of the current diagnostics performed in microplasmas. As an introduction to the regular special issue papers, a review paper is included [10]. It describes the key characteristics of atmospheric pressure plasmas and microplasmas in particular, and reviews the state of the art in plasma diagnostics. Special attention has been given in this review to highlighting the issues and challenges to probe microplasmas. The regular papers cover a large range of different diagnostics including coherent anti-Stokes Raman scattering (CARS) [11], (two-photon) laser induced fluorescence ((Ta)LIF) [12, 13, 18, 24], absorption spectroscopy [13-18], optical emission spectroscopy [12, 16-21, 24], imaging [22, 23], surface diagnostics [24, 25] and mass spectrometry [26, 27]. Different aspects of microplasmas are broadly investigated from a perspective of diagnostics, modelling and applications. Diagnostics are pivotal to both the development of models and the optimization and exploration of novel applications. Consequently, this special issue is focused on the various aspects and challenges for diagnostics in microplasmas. In addition, previous special issues on the topic of microplasmas have already covered many aspects of source development, applications and modelling [28-31]. The reader who wishes to access additional background information on microplasmas is referred to the following review papers [32-35]. We would like to thank all the contributors and the editorial staff who were of tremendous support in the preparation of this special issue. It is our sincere hope that you enjoy reading this special issue and that it will be a reference and helpful guidance for young researchers embarking in the field of microplasmas. The continued effort to increase our understanding of plasmas by modelling and diagnostics is of key importance for plasma science and the development of novel technologies. References [1] Eden J G, Park S-J, Herring C M and Bulson J M 2011 J. Phys. D: Appl. Phys. 44 224011 [2] Lucas N, Ermel V, Kurrat M and Buttgenbach S 2008 J. Phys. D: Appl. Phys. 41 215202 [3] Karnassios V 2004 Spectrochim. Acta B 59 909-28 [4] Mariotti D and Sankaran RM 2010 J. Phys. D: Appl. Phys. 43 323001 [5] Sakai O and Tachibana K 2012 Plasma Sources Sci. Technol. 21 013001 [6] Starikovskaia S M 2006 Plasma assisted ignition and combustion J. Phys. D.: Appl. Phys. 39 R265-99 [7] Fridman G, Friedman G, Gutsol A, Shekhter A B, Vasilets V N and Fridman A 2008 Plasma Process. Polym. 5 503-33 [8] Eden G et al 2013 IEEE Trans. Plasma Sci. 41 661-75 [9] Siemens W 1857 Poggendorffs. Ann. Phys. Chem. 102 66-122 [10] Bruggeman P and Brandenburg R 2013 J. Phys. D: Appl. Phys. 46 464001 [11] Montello A et al 2013 J. Phys. D: Appl. Phys. 46 464002 [12] Schröder D et al 2013 J. Phys. D: Appl. Phys. 46 464003 [13] Verreycken T et al 2013 J. Phys. D: Appl. Phys. 46 464004 [14] Sousa J S and Puech V 2013 J. Phys. D: Appl. Phys. 46 464005 [15] Takeda K et al 2013 J. Phys. D: Appl. Phys. 46 464006 [16] Vallade J and Massines F 2013 J. Phys. D: Appl. Phys. 46 464007 [17] Wang C and Wu W 2013 J. Phys. D: Appl. Phys. 46 464008 [18] Schröter S et al 2013 J. Phys. D: Appl. Phys. 46 464009 [19] Rusterholtz D L et al 2013 J. Phys. D: Appl. Phys. 46 464010 [20] Huang B-D et al 2013 J. Phys. D: Appl. Phys. 46 464011 [21] Pothiraja R et al 2013 J. Phys. D: Appl. Phys. 46 464012 [22] Marinov I et al 2013 J. Phys. D: Appl. Phys. 46 464013 [23] Akishev Y et al 2013 J. Phys. D: Appl. Phys. 46 464014 [24] Brandenburg R et al 2013 J. Phys. D: Appl. Phys. 46 464015 [25] Houlahan T J Jret al 2013 J. Phys. D: Appl. Phys. 46 464016 [26] Benedikt J et al 2013 J. Phys. D: Appl. Phys. 46 464017 [27] McKay K et al 2013 J. Phys. D: Appl. Phys. 46 464018 [28] Selected papers from the 2nd International Workshop on Microplasmas 2005 J. Phys. D: Appl. Phys. 38 1633-759 [29] Special issue: 3rd International Workshop on Microplasmas 2007 Control. Plasma Phys. 47 3-128 [30] Cluster issue on Microplasmas: 4th International Workshop on Microplasmas 2008 J. Phys. D: Appl. Phys. 41 1904001 [31] Microplasmas: scientific challenges and technological opportunities 2010 Eur. Phys. J. D 60 437-608 [32] Becker K H, Schoenbach K H and Eden J G 2006 J. Phys. D: Appl. Phys. 39 R55 [33] Iza F, Kim G J, Lee S M, Lee J K, Walsh J L, Zhang Y T and Kong M G 2008 Plasma Process. Polym. 5 322-44 [34] Tachibana K 2006 Trans. Electr. Electron. Eng. 1 145-55 [35] Samukawa S et al 2012 J. Phys. D: Appl. Phys. 45 253001

Preparing Physics and Chemistry Teachers at the University of Arizona

NASA Astrophysics Data System (ADS)

Novodvorsky, Ingrid

2006-04-01

Beginning in 2000, science majors at the University of Arizona who wish to teach in middle or high schools have enrolled in the College of Science Teacher Preparation Program (CoS TPP). Students in the program take General Education courses, content courses, and science pedagogy courses that make them eligible for teacher certification. Students can remain in their science degree programs, and take the required science pedagogy courses, or they can enroll in a BS in Science Education degree that includes the pedagogy courses, with concentrations available in Biology, Chemistry, Earth Science, and Physics. Science educators from six different departments, two permanent Adjunct Instructors, and two Teachers in Residence teach the program's courses. (One of the Teachers in Residence is supported by the PhysTEC project.) Most of the pedagogy courses include field experiences in area science classrooms; the program works with some 115 mentor teachers from throughout the Tucson area, who host preservice teachers in their field experiences. In the first six years of the program, 14 program graduates have been chemistry and physics teachers. This compares to a total of six chemistry and physics teachers produced by the College of Education program in the four years preceding the creation of the CoS TPP. In this presentation, I will describe the unique features of the courses that prospective chemistry and physics teachers take and the field experiences in which they participate. In addition, I will describe how PhysTEC-supplied resources have been used to improve the program, and the ways in which we are assessing the program's success.

Effective Practices for Training and Inspiring High School Physics Teachers

NASA Astrophysics Data System (ADS)

Magee-Sauer, Karen

It is well-documented that there is a nationwide shortage of highly qualified high school physics teachers. Not surprising, institutions of higher education report that the most common number of physics teacher graduates is zero with the majority of institutions graduating less than two physics teachers per year. With these statistics in mind, it is critical that institutions take a careful look at how they recruit, train, and contribute to the retention of high school physics teachers. PhysTEC is a partnership between the APS and AAPT that is dedicated to improving and promoting the education of high school physics teachers. Primarily funded by the NSF and its partnering organizations, PhysTEC has identified key components that are common to successful physics teacher preparation programs. While creating a successful training program in physics, it is also important that students have the opportunity for a ``do-able'' path to certification that does not add further financial debt. This talk will present an overview of ``what works'' in creating a path for physics majors to a high school physics teaching career, actions and activities that help train and inspire pre-service physics teachers, and frameworks that provide the support for in-service teachers. Obstacles to certification and the importance of a strong partnership with colleges of education will be discussed. Several examples of successful physics high school teacher preparation programs will be presented. This material is part of the Physics Teacher Education Coalition project, which is based upon work supported by the National Science Foundation under Grant Nos. 0808790, 0108787, and 0833210.

Aging and Rejuvenation with Fractional Derivatives

DTIC Science & Technology

2004-09-10

Chechkin , J. Klafter, V . Yu . Gonchar , R. Metzler, and L. V . Tanatarov, Phys. Rev. E 67, 010102(R) (2003). [12] I. M. Sokolov and R. Metzler, Phys. Rev. E 67...051106 (2001). [7] A . V . Chechkin , R. Gorenflo, and I. M. Sokolov, Phys. Rev. E 66, 046129 (2002). [8] J. Bisquert, Phys. Rev. Lett. 91, 010602 (2003...9] R. Metzler and J. Klafter, J. Phys. Chem. B 104 3851 (2000). [10] E. Barkai and R. J. Silbey, J. Phys. Chem. B 104 3866 (2000).

Performance of the JULES land surface model for UK Biogenic VOC emissions

NASA Astrophysics Data System (ADS)

Hayman, Garry; Comyn-Platt, Edward; Vieno, Massimo; Langford, Ben

2017-04-01

Emissions of biogenic non-methane volatile organic compounds (NMVOCs) are important for air quality and tropospheric composition. Through their contribution to the production of tropospheric ozone and secondary organic aerosol (SOA), biogenic VOCs indirectly contribute to climate forcing and climate feedbacks [1]. Biogenic VOCs encompass a wide range of compounds and are produced by plants for growth, development, reproduction, defence and communication [2]. There are both biological and physico-chemical controls on emissions [3]. Only a few of the many biogenic VOCs are of wider interest and only two or three (isoprene and the monoterpenes, α- and β-pinene) are represented in chemical transport models. We use the Joint UK Land Environment Simulator (JULES), the UK community land surface model, to estimate biogenic VOC emission fluxes. JULES is a process-based model that describes the water, energy and carbon balances and includes temperature, moisture and carbon stores [4, 5]. JULES currently provides emission fluxes of the 4 largest groups of biogenic VOCs: isoprene, terpenes, methanol and acetone. The JULES isoprene scheme uses gross primary productivity (GPP), leaf internal carbon and the leaf temperature as a proxy for the electron requirement for isoprene synthesis [6]. In this study, we compare JULES biogenic VOC emission estimates of isoprene and terepenes with (a) flux measurements made at selected sites in the UK and Europe and (b) gridded estimates for the UK from the EMEP/EMEP4UK atmospheric chemical transport model [7, 8], using site-specific or EMEP4UK driving meteorological data, respectively. We compare the UK-scale emission estimates with literature estimates. We generally find good agreement in the comparisons but the estimates are sensitive to the choice of the base or reference emission potentials. References (1) Unger, 2014: Geophys. Res. Lett., 41, 8563, doi:10.1002/2014GL061616; (2) Laothawornkitkul et al., 2009: New Phytol., 183, 27, doi:10.1111/j.1469-8137.2009.02859.x; (3) Grote and Niinemets, 2008: Plant Biol., 10, 8, doi:10.1055/s-2007-964975; (4) Best et al., 2011: Geosci. Model Dev., 4, 677, doi:10.5194/gmd-4-677-2011; (5) Clark et al., 2011: Geosci. Model Dev., 4, 701, doi:10.5194/gmd-4-701-2011; (6) Pacifico et al., 2011: Atmos. Chem. Phys., 11, 4371, doi:10.5194/acp-11-4371-2011; [7] Simpson et al., 2012: Atmos. Chem. Phys., 12, 7825, doi: 10.5194/acp-12-7825-2012; [8] Vieno et al., 2016: Atmos. Chem. Phys., 16, 265, doi: 10.5194/acp-16-265-2016.

Cardiovascular Small Heat Shock Protein HSPB7 Is a Kinetically Privileged Reactive Electrophilic Species (RES) Sensor.

PubMed

Surya, Sanjna L; Long, Marcus J C; Urul, Daniel A; Zhao, Yi; Mercer, Emily J; EIsaid, Islam M; Evans, Todd; Aye, Yimon

2018-02-08

Small heat shock protein (sHSP)-B7 (HSPB7) is a muscle-specific member of the non-ATP-dependent sHSPs. The precise role of HSPB7 is enigmatic. Here, we disclose that zebrafish Hspb7 is a kinetically privileged sensor that is able to react rapidly with native reactive electrophilic species (RES), when only substoichiometric amounts of RES are available in proximity to Hspb7 expressed in living cells. Among the two Hspb7-cysteines, this RES sensing is fulfilled by a single cysteine (C117). Purification and characterizations in vitro reveal that the rate for RES adduction is among the most efficient reported for protein-cysteines with native carbonyl-based RES. Covalent-ligand binding is accompanied by structural changes (increase in β-sheet-content), based on circular dichroism analysis. Among the two cysteines, only C117 is conserved across vertebrates; we show that the human ortholog is also capable of RES sensing in cells. Furthermore, a cancer-relevant missense mutation reduces this RES-sensing property. This evolutionarily conserved cysteine-biosensor may play a redox-regulatory role in cardioprotection.

Atmospheric ions, boreal forests and impacts on climate

NASA Astrophysics Data System (ADS)

Manninen, H. E.; Nieminen, T.; Franchin, A.; Järvinen, E.; Kontkanen, J.; Hirsikko, A.; Hõrrak, U.; Mirme, A.; Tammet, H.; Kerminen, V.-M.; Petäjä, T.; Kulmala, M.

2012-04-01

Aerosol particles play an important role in the Earth's atmosphere and in the climate system: They scatter and absorb solar radiation, facilitate chemical processes, and serve as seeds for cloud formation. The aerosol particles have direct cooling and warming effects on climate (IPCC, 2007). Secondary new particle formation (NPF) is a globally important source of aerosol particles (Kulmala and Kerminen, 2008). Currently, the mechanisms of particle formation and the vapors participating in this process are, however, not truly understood. Several formation and growth mechanisms have been proposed for the very first steps of the process: homogeneous, heterogeneous, ion-induced and kinetic nucleation and activation type cluster growth. Small ions are part of the atmospheric aerosol spectrum, and in atmospheric sciences study of ion-aerosol interactions is essential. Small ions are small molecular clusters carrying a net electric charge. They are produced by ionisation of molecules in the air. Typically the small ion concentrations vary in the range of 100-2000 cm-3 in both polarities (Hirsikko et al., 2011). Ion-induced NPF is limited by the ion production rate, which typically is around 10 ion pairs cm-3s-1 in the boundary layer over the ground. The ion production rate has strong spatial and temporal dependence. The ionisation mechanisms change with altitude: radon and gamma radiation from the ground and galactic cosmic rays dominate close to the Earth's surface, while higher in the free troposphere cosmic rays become the main driving factor. In order to fully explain atmospheric NPF and subsequent growth, we need to measure directly the very initial steps of the formation processes. Air ion spectrometers measure the mobility distributions of charged aerosol particles in the mobility diameter range of 0.8-42 nm (Mirme et al., 2007; Tammet et al., 2011). Neutral cluster and air ion spectrometers measure additionally the mobility distribution of neutral particles larger than 2 nm in diameter by charging the aerosol sample with unipolar corona chargers (Manninen et al., 2009). According to earlier studies, the atmospheric nucleation and cluster activation take place at the mobility diameter range of 1.5-2 nm. Therefore, the ion spectrometers allow direct measurements at exactly the size where atmospheric nucleation takes place. The results indicate that the ion-induced nucleation contributes ~1-30% to the NPF events in most atmospheric conditions (Manninen et al., 2010). In other words, neutral particle formation seems to dominate over ion-mediated mechanisms, at least in the boreal forest conditions. Acknowledgements. This research was supported by the Academy of Finland Center of Excellence program (project number 1118615). Hirsikko, A. et al.: Atmospheric ions and nucleation: a review of observations, Atmos. Chem. Phys., 11, 767-798, 2011. IPCC, Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 996 pp, 2007. Kulmala, M., and Kerminen, V.-M.: On the growth of atmospheric nanoparticles, Atmos. Res., 90, 132-150, 2008. Manninen, H.E. et al.: Long-term field measurements of charged and neutral clusters using Neutral cluster and Air Ion Spectrometer (NAIS). Boreal Env. Res. 14, 591-605, 2009. Manninen, H.E. et al., EUCAARI ion spectrometer measurements at 12 European sites - analysis of new particle formation events, Atmos. Chem. Phys., 10, 7907-7927, 2010. Mirme, A. et al.: A Wide-range multi-channel Air Ion Spectrometer, Boreal Environ. Res., 12, 247-264, 2007. Tammet, H.: Symmetric inclined grid mobility analyzer for the measurement of charged clusters and fine nanoparticles in atmospheric air. Aerosol Science and Technology, 45, 468 - 479, 2011.

New Fks hot spot for acquired echinocandin resistance in Saccharomyces cerevisiae and its contribution to intrinsic resistance of Scedosporium species.

PubMed

Johnson, Michael E; Katiyar, Santosh K; Edlind, Thomas D

2011-08-01

Echinocandins represent a new antifungal group with potent activity against Candida species. These lipopeptides inhibit the synthesis of β-1,3-glucan, the major cell wall polysaccharide. Acquired resistance or reduced echinocandin susceptibility (RES) is rare and associated with mutations in two "hot spot" regions of Fks1 or Fks2, the probable β-1,3-glucan synthases. In contrast, many fungi demonstrate intrinsic RES for reasons that remain unclear. We are using Saccharomyces cerevisiae to understand the basis for RES by modeling echinocandin-Fks interaction. Previously characterized mutations confer cross-RES; we screened for mutations conferring differential RES, implying direct interaction of that Fks residue with a variable echinocandin side chain. One mutant (in an fks1Δ background) exhibited ≥16-fold micafungin and anidulafungin versus caspofungin RES. Sequencing identified a novel Fks2 mutation, W714L/Y715N. Equivalent W695L/Y696N and related W695L/F/C mutations in Fks1 generated by site-directed mutagenesis and the isolation of a W695L-equivalent mutation in Candida glabrata confirmed the role of the new "hot spot 3" in RES. Further mutagenesis expanded hot spot 3 to Fks1 residues 690 to 700, yielding phenotypes ranging from cross-RES to differential hypersusceptibility. Fks1 sequences from intrinsically RES Scedosporium species revealed W695F-equivalent substitutions; Fks1 hybrids expressing Scedosporium prolificans hot spot 3 confirmed that this substitution imparts RES.

How Much Is Enough?

DTIC Science & Technology

2015-01-01

argues that pay appears to be an ambivalent fac- tor in job satisfaction or dissatisfaction.20 Additionally, a 2012 survey by the Center for Strategic and...Cohn, “Who Will Serve? Labour Markets and Military Personnel Policy,” Res Militaris 3, no. 2 (Winter–Spring 2013): http://www.resmilitaris.net...ence to Education (New York: Columbia University Press, 1975). 11. Bruce C. Greenwald, “Adverse Selection in the Labour Market,” Review of Economic

Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

NASA Astrophysics Data System (ADS)

Järveoja, J.; Peichl, M.; Maddison, M.; Soosaar, K.; Vellak, K.; Karofeld, E.; Teemusk, A.; Mander, Ü.

2015-10-01

Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting water table levels (WTL) on the annual C and GHG balances of restoration treatments with high (Res-H) and low (Res-L) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res-H relative to Res-L. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res-L compared to Res-H. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between Res-H and Res-L. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges in Res-H and Res-L, respectively. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, Res-H, Res-L and BP were C sources of 111, 103 and 268 g C m-2 yr-1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha-1 yr-1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments three years following restoration. However, the C and GHG balances in Res-H and Res-L were considerably lower than in BP owing to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

Three-electron spin qubits

NASA Astrophysics Data System (ADS)

Russ, Maximilian; Burkard, Guido

2017-10-01

The goal of this article is to review the progress of three-electron spin qubits from their inception to the state of the art. We direct the main focus towards the exchange-only qubit (Bacon et al 2000 Phys. Rev. Lett. 85 1758-61, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each three-spin qubit we describe the qubit model, the envisioned physical realization, the implementations of single-qubit operations, as well as the read-out and initialization schemes. Two-qubit gates and decoherence properties are discussed for the RX qubit and the exchange-only qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the charge-stability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchange-only qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spin-charge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchange-only qubit and its modification, the RX qubit, whose single-qubit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of two-qubit operations are presented for the exchange-only qubits which can be divided into short-ranged and long-ranged interactions. Both of these interaction types are expected to be necessary in a large-scale quantum computer. The short-ranged interactions use the exchange coupling by placing qubits next to each other and applying exchange-pulses (DiVincenzo et al 2000 Nature 408 339, Fong and Wandzura 2011 Quantum Inf. Comput. 11 1003, Setiawan et al 2014 Phys. Rev. B 89 085314, Zeuch et al 2014 Phys. Rev. B 90 045306, Doherty and Wardrop 2013 Phys. Rev. Lett. 111 050503, Shim and Tahan 2016 Phys. Rev. B 93 121410), while the long-ranged interactions use the photons of a superconducting microwave cavity as a mediator in order to couple two qubits over long distances (Russ and Burkard 2015 Phys. Rev. B 92 205412, Srinivasa et al 2016 Phys. Rev. B 94 205421). The nature of the three-electron qubit states each having the same total spin and total spin in z-direction (same Zeeman energy) provides a natural protection against several sources of noise (DiVincenzo et al 2000 Nature 408 339, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Kempe et al 2001 Phys. Rev. A 63 042307, Russ and Burkard 2015 Phys. Rev. B 91 235411). The price to pay for this advantage is an increase in gate complexity. We also take into account the decoherence of the qubit through the influence of magnetic noise (Ladd 2012 Phys. Rev. B 86 125408, Mehl and DiVincenzo 2013 Phys. Rev. B 87 195309, Hung et al 2014 Phys. Rev. B 90 045308), in particular dephasing due to the presence of nuclear spins, as well as dephasing due to charge noise (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434), fluctuations of the energy levels on each dot due to noisy gate voltages or the environment. Several techniques are discussed which partly decouple the qubit from magnetic noise (Setiawan et al 2014 Phys. Rev. B 89 085314, West and Fong 2012 New J. Phys. 14 083002, Rohling and Burkard 2016 Phys. Rev. B 93 205434) while for charge noise it is shown that it is favorable to operate the qubit on the so-called ‘(double) sweet spots’ (Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434, Malinowski et al 2017 arXiv: 1704.01298), which are least susceptible to noise, thus providing a longer lifetime of the qubit.

Hi-Res scan mode in clinical MDCT systems: Experimental assessment of spatial resolution performance

PubMed Central

Cruz-Bastida, Juan P.; Gomez-Cardona, Daniel; Li, Ke; Sun, Heyi; Hsieh, Jiang; Szczykutowicz, Timothy P.; Chen, Guang-Hong

2016-01-01

Purpose: The introduction of a High-Resolution (Hi-Res) scan mode and another associated option that combines Hi-Res mode with the so-called High Definition (HD) reconstruction kernels (referred to as a Hi-Res/HD mode in this paper) in some multi-detector CT (MDCT) systems offers new opportunities to increase spatial resolution for some clinical applications that demand high spatial resolution. The purpose of this work was to quantify the in-plane spatial resolution along both the radial direction and tangential direction for the Hi-Res and Hi-Res/HD scan modes at different off-center positions. Methods: A technique was introduced and validated to address the signal saturation problem encountered in the attempt to quantify spatial resolution for the Hi-Res and Hi-Res/HD scan modes. Using the proposed method, the modulation transfer functions (MTFs) of a 64-slice MDCT system (Discovery CT750 HD, GE Healthcare) equipped with both Hi-Res and Hi-Res/HD modes were measured using a metal bead at nine different off-centered positions (0–16 cm with a step size of 2 cm); at each position, both conventional scans and Hi-Res scans were performed. For each type of scan and position, 80 repeated acquisitions were performed to reduce noise induced uncertainties in the MTF measurements. A total of 15 reconstruction kernels, including eight conventional kernels and seven HD kernels, were used to reconstruct CT images of the bead. An ex vivo animal study consisting of a bone fracture model was performed to corroborate the MTF results, as the detection of this high-contrast and high frequency task is predominantly determined by spatial resolution. Images of this animal model generated by different scan modes and reconstruction kernels were qualitatively compared with the MTF results. Results: At the centered position, the use of Hi-Res mode resulted in a slight improvement in the MTF; each HD kernel generated higher spatial resolution than its counterpart conventional kernel. However, the MTF along the tangential direction of the scan field of view (SFOV) was significantly degraded at off-centered positions, yet the combined Hi-Res/HD mode reduced this azimuthal MTF degradation. Images of the animal bone fracture model confirmed the improved spatial resolution at the off-centered positions through the use of the Hi-Res mode and HD kernels. Conclusions: The Hi-Res/HD scan improve spatial resolution of MDCT systems at both centered and off-centered positions. PMID:27147351

Hi-Res scan mode in clinical MDCT systems: Experimental assessment of spatial resolution performance.

PubMed

Cruz-Bastida, Juan P; Gomez-Cardona, Daniel; Li, Ke; Sun, Heyi; Hsieh, Jiang; Szczykutowicz, Timothy P; Chen, Guang-Hong

2016-05-01

The introduction of a High-Resolution (Hi-Res) scan mode and another associated option that combines Hi-Res mode with the so-called High Definition (HD) reconstruction kernels (referred to as a Hi-Res/HD mode in this paper) in some multi-detector CT (MDCT) systems offers new opportunities to increase spatial resolution for some clinical applications that demand high spatial resolution. The purpose of this work was to quantify the in-plane spatial resolution along both the radial direction and tangential direction for the Hi-Res and Hi-Res/HD scan modes at different off-center positions. A technique was introduced and validated to address the signal saturation problem encountered in the attempt to quantify spatial resolution for the Hi-Res and Hi-Res/HD scan modes. Using the proposed method, the modulation transfer functions (MTFs) of a 64-slice MDCT system (Discovery CT750 HD, GE Healthcare) equipped with both Hi-Res and Hi-Res/HD modes were measured using a metal bead at nine different off-centered positions (0-16 cm with a step size of 2 cm); at each position, both conventional scans and Hi-Res scans were performed. For each type of scan and position, 80 repeated acquisitions were performed to reduce noise induced uncertainties in the MTF measurements. A total of 15 reconstruction kernels, including eight conventional kernels and seven HD kernels, were used to reconstruct CT images of the bead. An ex vivo animal study consisting of a bone fracture model was performed to corroborate the MTF results, as the detection of this high-contrast and high frequency task is predominantly determined by spatial resolution. Images of this animal model generated by different scan modes and reconstruction kernels were qualitatively compared with the MTF results. At the centered position, the use of Hi-Res mode resulted in a slight improvement in the MTF; each HD kernel generated higher spatial resolution than its counterpart conventional kernel. However, the MTF along the tangential direction of the scan field of view (SFOV) was significantly degraded at off-centered positions, yet the combined Hi-Res/HD mode reduced this azimuthal MTF degradation. Images of the animal bone fracture model confirmed the improved spatial resolution at the off-centered positions through the use of the Hi-Res mode and HD kernels. The Hi-Res/HD scan improve spatial resolution of MDCT systems at both centered and off-centered positions.

A Physical Model of Cosmogenic Nuclide Production in Stony and Iron Meteoroids on the Basis of Simulation Experiments

NASA Astrophysics Data System (ADS)

Leya, I.; Lange, H.-J.; Michel, R.; Meltzow, B.; Herpers, U.; Busemann, H.; Wieler, R.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.

1995-09-01

By extending and improving earlier model calculations [1-4] of cosmogenic nuclide production by GCR particles in extraterrestrial matter, we can now present a physical model without free parameters for a consistent description of GCR production rates in stony and iron meteoroids. The model takes explicitely into account p and n-induced reactions. GCR 4He particles are considered only approximately. It is based on depth-size and bulk-chemistry-dependent spectra of primary and secondary protons and of secondary neutrons calculated by HET and MORSE codes within the HERMES code system [5] and on the cross sections of the underlying reactions. Comprehensive and reliable sets of proton cross sections from thresholds up to 2.6 GeV exist now for many cosmogenic nuclides (see [6] for a review). For n-induced reactions the situation is not so good. Only a few data at low energies and practically no data at higher energies exist. GCR production of cosmogenic nuclides in stony meteoroids is already dominated by neutron-induced reactions for most meteoroid radii. In iron meteoroids neutrons are even more important because of the high mass numbers of the bulk and of consequently higher multiplicities for production of secondary neutrons. In order to overcome this problem, the necessary excitation functions of neutron-induced reactions were determined from experimental thick-target production rates by least-squares unfolding procedures using the code STAYS'L [7]. The data were produced in laboratory experiments under completely controlled conditions [8-11]. The unfolding procedure starts from guess functions (from threshold up to 900 MeV) based on all available experimental neutron cross sections and on theoretical ones calculated by the AREL [12] code which is a relativistic version of the hybrid model of pre-equilibrium reactions [13]. With the new neutron cross sections it is possible to describe simultanously all data from the simulation experiments with an accuracy of better than 10 % and to calculate consistent cosmogenic nuclide production rates in stony and iron meteoroids. The new model calculations are so far valid for 10Be, 26Al, 36Cl, 41Ca, 53Mn as well as He, Ne and Ar isotopes. The new theoretical production rates are compared with measured depth profiles in stony and iron meteorites and will be discussed with respect to primary GCR spectra and preatmospheric radii and exposure histories of stony and iron meteoroids. Acknowledgement: This work was partially supported by the Deutsche Forschungsgemeinschaft and the Swiss National Science Foundation. References: [1] Michel R. et al. (1991) Meteoritics, 26, 221-242. [2] Michel R. et al. (1995) Planet. Space Sci., in press. [3] Bhandari N. et al. (1993) GCA, 57, 2361-2375. [4] Herpers U. et al. (1995) Planet. Space Sci., in press. [5] Cloth P. et al. (1988) JUEL-2203. [6] Michel R. (1994) in Nuclear Data for Science and Technology (J. K. Dickens, ed.), 337-343, Am. Nucl. Soc., La Grange Park. [7] Perrey F. G. (1977) Code STAYS'L, NEA Data Bank, OECD Paris. [8] Michel R. et al. (1986) Nucl. Instr. Meth. Phys. Res., B16, 61-82. [9] Michel R. et al. (1989) Nucl. Instr. Meth. Phys. Res., B42, 76-100. [10] Michel R. et al. (1993) J. Radioanal. Nucl. Chem., 169, 13-25. [11] Michel R. et al. (1994) in Nuclear Data for Science and Technology (J. K. Dickens, ed.), 377-379, Am. Nucl. Soc., La Grange Park. [12] Blann M. (1994) Code AREL, personal communication to R. Michel. [13] Blann M. (1972) Phys. Rev. Lett., 27, 337-340.

Far Infrared, Magnetic and Electronic Studies of High Tc Superconducting Materials

DTIC Science & Technology

1992-09-30

Phys. Rev. Left. 63, 2421(1989). 8. K. H. Fischer and T. Nattermann, Phys. Rev. .43, 10372(1991). 9. R. E. Walstedt, R. F. Bell, and D. B. Mitzi , Phys...Duran, J. Yazyi, F. dela Cruz, D. J. Bishop, D. B. Mitzi , and A. Kapitulnik, Phys. Rev. B 44, 17737(1991). 14. Y. Yeshurun and A. P. Malozemoff, Phys

The Mpemba Effect, Shechtman's Quasicrystals and Student Exploration Activities

ERIC Educational Resources Information Center

Balazovic, Marek; Tomasik, Boris

2012-01-01

In the 1960s, Tanzanian student Erasto Mpemba and his teacher published a paper with the title "Cool?" in this journal (Mpemba and Osborne 1969 "Phys. Educ." 4 172-5). They claimed that hot water freezes more quickly than cold water. The paper not only led to a wave of discussion, and more publications about this topic, but also to a whole series…

Three Important Taylor Series for Introductory Physics

DTIC Science & Technology

2009-09-01

series by the sum of its first few terms is useful throughout an introductory physics course . Example applications [1, 2] include estimating square...Lat. Am. J. Phys. Educ. Vol. 3, No. 3, Sept. 2009 535 http://www.journal.lapen.org.mx Three Important Taylor Series for Introductory Physics...one dimension, which instructively ties the mathematical development to physics concepts already presented in introductory courses . Keywords

New Fks Hot Spot for Acquired Echinocandin Resistance in Saccharomyces cerevisiae and Its Contribution to Intrinsic Resistance of Scedosporium Species▿

PubMed Central

Johnson, Michael E.; Katiyar, Santosh K.; Edlind, Thomas D.

2011-01-01

Echinocandins represent a new antifungal group with potent activity against Candida species. These lipopeptides inhibit the synthesis of β-1,3-glucan, the major cell wall polysaccharide. Acquired resistance or reduced echinocandin susceptibility (RES) is rare and associated with mutations in two “hot spot” regions of Fks1 or Fks2, the probable β-1,3-glucan synthases. In contrast, many fungi demonstrate intrinsic RES for reasons that remain unclear. We are using Saccharomyces cerevisiae to understand the basis for RES by modeling echinocandin-Fks interaction. Previously characterized mutations confer cross-RES; we screened for mutations conferring differential RES, implying direct interaction of that Fks residue with a variable echinocandin side chain. One mutant (in an fks1Δ background) exhibited ≥16-fold micafungin and anidulafungin versus caspofungin RES. Sequencing identified a novel Fks2 mutation, W714L/Y715N. Equivalent W695L/Y696N and related W695L/F/C mutations in Fks1 generated by site-directed mutagenesis and the isolation of a W695L-equivalent mutation in Candida glabrata confirmed the role of the new “hot spot 3” in RES. Further mutagenesis expanded hot spot 3 to Fks1 residues 690 to 700, yielding phenotypes ranging from cross-RES to differential hypersusceptibility. Fks1 sequences from intrinsically RES Scedosporium species revealed W695F-equivalent substitutions; Fks1 hybrids expressing Scedosporium prolificans hot spot 3 confirmed that this substitution imparts RES. PMID:21576441

The protective effects of resveratrol on Schwann cells with toxicity induced by ethanol in vitro.

PubMed

Yuan, Hongtu; Zhang, Jingfen; Liu, Huaxiang; Li, Zhenzhong

2013-09-01

Schwann cells (SCs) are the myelin forming cells in the peripheral nervous system, they play a key role in the pathology of various polyneuropathies and provide trophic support to axons via expression of various neurotrophic factors, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). Ethanol (EtOH) adversely affected both SCs proliferation and myelin formation in culture. Resveratrol (Res) has been shown to regulate many cellular processes and to display multiple protective and therapeutic effects. Whether Res has protective effects on SCs with EtOH-induced toxicity is still unclear. The protective efficacy of Res on EtOH-treated SCs in vitro was investigated in the present study. Res improved cell viability of the EtOH-treated SCs. Hoechst 33342 staining and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate nick-end labeling analysis showed that the EtOH-induced apoptosis was inhibited by Res. The effects of Res were blocked by the 5'-adenosine monophosphate-activated protein kinase inhibitor Compound C and the silencing information regulator T1 inhibitor nicotinamide. Res could increase the mRNA and protein levels of BDNF and GDNF in the EtOH-treated SCs. However, the EtOH-induced increase of NGF in the SCs is inhibited by Res. The data from the present study indicate that Res protects SCs from EtOH-induced cell death and regulates the expression of neurotrophicfactors. Res and its derivative may be effective for the treatment of neuropathic diseases induced by EtOH. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dimethyl Sulfoxide Attenuates Acute Lung Injury Induced by Hemorrhagic Shock/Resuscitation in Rats.

PubMed

Tsung, Yu-Chi; Chung, Chih-Yang; Wan, Hung-Chieh; Chang, Ya-Ying; Shih, Ping-Cheng; Hsu, Han-Shui; Kao, Ming-Chang; Huang, Chun-Jen

2017-04-01

Inflammation following hemorrhagic shock/resuscitation (HS/RES) induces acute lung injury (ALI). Dimethyl sulfoxide (DMSO) possesses anti-inflammatory and antioxidative capacities. We sought to clarify whether DMSO could attenuate ALI induced by HS/RES. Male Sprague-Dawley rats were allocated to receive either a sham operation, sham plus DMSO, HS/RES, or HS/RES plus DMSO, and these were denoted as the Sham, Sham + DMSO, HS/RES, or HS/RES + DMSO group, respectively (n = 12 in each group). HS/RES was achieved by drawing blood to lower mean arterial pressure (40-45 mmHg for 60 min) followed by reinfusion with shed blood/saline mixtures. All rats received an intravenous injection of normal saline or DMSO immediately before resuscitation or at matching points relative to the sham groups. Arterial blood gas and histological assays (including histopathology, neutrophil infiltration, and lung water content) confirmed that HS/RES induced ALI. Significant increases in pulmonary expression of tumor necrosis factor-α (TNF-α), malondialdehyde, nuclear factor-kappa B (NF-κB), inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2) confirmed that HS/RES induced pulmonary inflammation and oxidative stress. DMSO significantly attenuated the pulmonary inflammation and ALI induced by HS/RES. The mechanisms for this may involve reducing inflammation and oxidative stress through inhibition of pulmonary NF-κB, TNF-α, iNOS, and COX-2 expression.

Resveratrol stimulates mitochondrial fusion by a mechanism requiring mitofusin-2.

PubMed

Robb, Ellen L; Moradi, Fereshteh; Maddalena, Lucas A; Valente, Andrew J F; Fonseca, Joao; Stuart, Jeffrey A

2017-04-01

Resveratrol (RES) is a plant-derived stilbene associated with a wide range of health benefits. Mitochondria are a key downstream target of RES, and in some cell types RES promotes mitochondrial biogenesis, altered cellular redox status, and a shift toward oxidative metabolism. Mitochondria exist as a dynamic network that continually remodels via fusion and fission processes, and the extent of fusion is related to cellular redox status and metabolism. We investigated RES's effects on mitochondrial network morphology in several cell lines using a quantitative approach to measure the extent of network fusion. 48 h continuous treatment with 10-20 μM RES stimulated mitochondrial fusion in C2C12 myoblasts, PC3 cancer cells, and mouse embryonic fibroblasts stimulated significant increases in fusion in all instances, resulting in larger and more highly branched mitochondrial networks. Mitofusin-2 (Mfn2) is a key protein facilitating mitochondrial fusion, and its expression was also stimulated by RES. Using Mfn2-null cells we demonstrated that RES's effects on mitochondrial fusion, cellular respiration rates, and cell growth are all dependent upon the presence of Mfn2. Taken together, these results demonstrate that Mfn2 and mitochondrial fusion are affected by RES in ways that appear to relate to RES's known effects on cellular metabolism and growth. Copyright © 2017 Elsevier Inc. All rights reserved.

Zoledronate and ion-releasing resins impair dentin collagen degradation.

PubMed

Tezvergil-Mutluay, A; Seseogullari-Dirihan, R; Feitosa, V P; Tay, F R; Watson, T F; Pashley, D H; Sauro, S

2014-10-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. © International & American Associations for Dental Research.

Zoledronate and Ion-releasing Resins Impair Dentin Collagen Degradation

PubMed Central

Tezvergil-Mutluay, A.; Seseogullari-Dirihan, R.; Feitosa, V.P.; Tay, F.R.; Watson, T.F.; Pashley, D.H.; Sauro, S.

2014-01-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. PMID:25074494

Protective effects of resveratrol and its analogs on age-related macular degeneration in vitro.

PubMed

Kang, Jung-Hwan; Choung, Se-Young

2016-12-01

Damage of retinal pigment epithelial (RPE) cells by A2E may be critical for age-related macular degeneration (AMD) management. Accumulation and photooxidation of A2E are known to be one of the critical causes in AMD. Here, we evaluated the protective effect of resveratrol (RES), piceatannol (PIC) and RES glycones on blue-light-induced RPE cell death caused by A2E photooxidation. A2E treatment followed by blue light exposure caused significant damages on human RPE cells (ARPE-19). But the damages were attenuated by post- and pre-treatment of RES and PIC in our in vitro models. The results of cell free system and FAB-MS analysis clearly showed that the reduction of A2E by blue light exposure was significantly rescued, and that oxidized forms of A2E were significantly reduced by RES or PIC treatment. Besides, RES or PIC inhibited the intracellular accumulation of A2E. Not only RES and PIC but RES glycones showed protection of ARPE-19 cells against A2E and blue-light-induced photo-damage. These findings demonstrate that RES and its analogs may have protective effects against A2E and blue-light-induced ARPE-19 cell death through regulation of A2E accumulation as well as photooxidation of A2E. Thus RES and its analogs may be beneficial for AMD treatment.

Hydrogen-induced structural transition in single layer ReS2

NASA Astrophysics Data System (ADS)

Yagmurcukardes, M.; Bacaksiz, C.; Senger, R. T.; Sahin, H.

2017-09-01

By performing density functional theory-based calculations, we investigate how structural, electronic and mechanical properties of single layer ReS2 can be tuned upon hydrogenation of its surfaces. It is found that a stable, fully hydrogenated structure can be obtained by formation of strong S-H bonds. The optimized atomic structure of ReS2H2 is considerably different than that of the monolayer ReS2 which has a distorted-1T phase. By performing phonon dispersion calculations, we also predict that the Re2-dimerized 1T structure (called 1T {{}\\text{R{{\\text{e}}2}}} ) of the ReS2H2 is dynamically stable. Unlike the bare ReS2 the 1T {{}\\text{R{{\\text{e}}2}}} -ReS2H2 structure which is formed by breaking the Re4 clusters into separated Re2 dimers, is an indirect-gap semiconductor. Furthermore, mechanical properties of the 1T {{}\\text{R{{\\text{e}}2}}} phase in terms of elastic constants, in-plane stiffness (C) and Poisson ratio (ν) are investigated. It is found that full hydrogenation not only enhances the flexibility of the single layer ReS2 crystal but also increases anisotropy of the elastic constants.

Investigation of the High, Finite n Ballooning Mode Limit for Compact Quasi-Axially Symmetric Stellarators

NASA Astrophysics Data System (ADS)

Redi, Martha; Canik, John; Fredrickson, E.; Fu, G.; Nuehrenberg, C.; Boozer, A. H.

2000-10-01

The standard ballooning-mode beta limit comes from an infinite-n, radially local, ideal magnetohydrodynamic (MHD) calculation. Finite-n ballooning modes have been observed in tokamak plasmas [1]. Investigations of optimized quasiaxially symmetric stellarators with three dimensional, global, ideal MHD codes have recently shown good stability for the external kink, ``vertical" and infinite-n ballooning modes [2,3]. However, infinite-n ballooning stability may be too restrictive, due to its sensitivity to features in the local shear and curvature. The CAS3D [4] code is being used to compare the stability of the high-n ballooning modes to the infinite-n calculations from TERPSICHORE [5]. [1] E. Fredrickson, et al. Phys. Plas. 3 (1996) 2620. [2] G. Fu, Phys. Plas. 7 (2000)1079; Phys. Plas. 7 (2000) 1809. M. Redi, et al. Phys. Plas 7 (2000)1911. [3] A. Reiman, et al., Plas. Phys. Cont. Fus. 41 (1999) B273. [4] C. Nuehrenberg, Phys. Plas. 6 (1999) 275. C. Nuehrenberg, Phys. Plas. 3 (1996) 2401. C. Schwab, Phys. Fluids B5 (1993) 3195. [5] W. A. Cooper, Phys. Plas. 3 (1996) 275.

Chemical Vapor Deposition Growth of Degenerate p-Type Mo-Doped ReS2 Films and Their Homojunction.

PubMed

Qin, Jing-Kai; Shao, Wen-Zhu; Xu, Cheng-Yan; Li, Yang; Ren, Dan-Dan; Song, Xiao-Guo; Zhen, Liang

2017-05-10

Substitutional doping of transition metal dichalcogenide two-dimensional materials has proven to be effective in tuning their intrinsic properties, such as band gap, transport characteristics, and magnetism. In this study, we realized substitutional doping of monolayer rhenium disulfide (ReS 2 ) with Mo via chemical vapor deposition. Scanning transmission electron microscopy demonstrated that Mo atoms are successfully doped into ReS 2 by substitutionally replacing Re atoms in the lattice. Electrical measurements revealed the degenerate p-type semiconductor behavior of Mo-doped ReS 2 field effect transistors, in agreement with density functional theory calculations. The p-n diode device based on a doped ReS 2 and ReS 2 homojunction exhibited gate-tunable current rectification behaviors, and the maximum rectification ratio could reach up to 150 at V d = -2/+2 V. The successful synthesis of p-type ReS 2 in this study could largely promote its application in novel electronic and optoelectronic devices.

Mastery of Content Representation (CoRes) Related TPACK High School Biology Teacher

NASA Astrophysics Data System (ADS)

Nasution, W. R.; Sriyati, S.; Riandi, R.; Safitri, M.

2017-09-01

The purpose of this study was to determine the mastery of Content Representation (CoRes) teachers related to the integration of technology and pedagogy in teaching Biology (TPACK). This research uses a descriptive method. The data were taken using instruments CoRes as the primary data and semi-structured interviews as supporting data. The subjects were biology teacher in class X MIA from four schools in Bandung. Teachers raised CoRes was analyzed using a scoring rubric CoRes with coding 1-3 then categorized into a group of upper, middle, or lower. The results showed that the two teachers in the lower category. This results means that the control of teachers in defining the essential concept in the CoRes has not been detailed and specific. Meanwhile, two other teachers were in the middle category. This means that the ability of teachers to determine the essential concepts in the CoRes are still inadequate so that still needs to be improved.

The AAPT/ComPADRE Digital Library: Supporting Physics Education at All Levels

NASA Astrophysics Data System (ADS)

Mason, Bruce

For more than a decade, the AAPT/ComPADRE Digital Library has been providing online resources, tools, and services that support broad communities of physics faculty and physics education researchers. This online library provides vetted resources for teachers and students, an environment for authors and developers to share their work, and the collaboration tools for a diverse set of users. This talk will focus on the recent collaborations and developments being hosted on or developed with ComPADRE. Examples include PhysPort, making the tools and resources developed by physics education researchers more accessible, the Open Source Physics project, expanding the use of numerical modeling at all levels of physics education, and PICUP, a community for those promoting computation in the physics curriculum. NSF-0435336, 0532798, 0840768, 0937836.

Link-Prediction Enhanced Consensus Clustering for Complex Networks (Open Access)

DTIC Science & Technology

2016-05-20

92:022816. Available from: http://link.aps.org/doi/10.1103/PhysRevE.92.022816. doi: 10. 1103 /PhysRevE.92.022816 16. Aldecoa R, Marín I. Exploring the...from: http://link.aps.org/doi/10.1103/PhysRevE.80.056117. doi: 10. 1103 /PhysRevE.80.056117 18. Dahlin J, Svenson P. Ensemble approaches for improving...046110. Available from: http://link.aps.org/doi/10.1103/PhysRevE.81.046110. doi: 10. 1103 /PhysRevE.81.046110 28. Gfeller D, Chappelier JC, De Los Rios P

Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

NASA Astrophysics Data System (ADS)

Järveoja, Järvi; Peichl, Matthias; Maddison, Martin; Soosaar, Kaido; Vellak, Kai; Karofeld, Edgar; Teemusk, Alar; Mander, Ülo

2016-05-01

Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m-2 yr-1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha-1 yr-1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

Protective effects of resveratrol on postmenopausal osteoporosis: regulation of SIRT1-NF-κB signaling pathway.

PubMed

Feng, Jing; Liu, Shuai; Ma, Sai; Zhao, Jian; Zhang, Wei; Qi, Wei; Cao, Pengchong; Wang, Zheng; Lei, Wei

2014-12-01

Postmenopausal osteoporosis severely jeopardizes human health. Seeking for therapeutic drugs without side effects is of great necessity. Our study was designed to investigate whether resveratrol, an agonist of SIRT1, could have favorable effect on osteoporosis and to explore the underlying mechanisms. Rat osteoporosis model (ovariectomy group, OVX) was established by bilateral ovariectomy. Three different doses of resveratrol were used: 5 mg/kg/d (low-dosed, RES(LD)), 25 mg/kg/d (medium-dosed, RES(MD)), and 45 mg/kg/d (high-dosed, RES(HD)). Results showed that RES(LD) did not show any significant effect on OVX alterations, while RES(MD) and RES(HD) significantly elevated the decreased bone mineral density induced by osteoporosis (RES(MD) 0.205 ± 0.023, RES(HD) 0.214 ± 0.053 vs. OVX 0.165 ± 0.050 g/cm(2) respectively; P < 0.05). Serum markers alkaline phosphatase (ALP) and osteocalcin were moderately restored by resveratrol. Moreover, resveratrol improved bone structure in OVX rats, demonstrated by hematoxylin-eosin staining and micro-computed tomographic results. In vitro results revealed that resveratrol promoted osteoblast differentiation of bone marrow mesenchymal stromal cells, evidenced by the increase of ALP generation and mRNA expression of collagen 1 (P < 0.05; RES(MD), RES(HD) vs. control group). SIRT1 gene silencing by siRNA transfection blocked these beneficial effects of resveratrol (P < 0.05; RES + SIRT1(KD) vs. RES(HD)). Western blot results showed that resveratrol activated SIRT1 and subsequently suppressed the activity of NF-κB with decreased expression level of p-IκBα and NF-κB p65 (P < 0.05). Our findings verified the effects of specific dosed resveratrol on postmenopausal osteoporosis through osteoblast differentiation via SIRT1-NF-κB signaling pathway. This study suggested the therapeutic potential of resveratrol against osteoporosis and stressed the importance of effective doses. © The Author 2014. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

Regional Emphysema Score Predicting Overall Survival, Quality of Life, and Pulmonary Function Recovery in Early-Stage Lung Cancer Patients.

PubMed

Dai, Jie; Liu, Ming; Swensen, Stephen J; Stoddard, Shawn M; Wampfler, Jason A; Limper, Andrew H; Jiang, Gening; Yang, Ping

2017-05-01

Pulmonary emphysema is a frequent comorbidity in lung cancer, but its role in tumor prognosis remains obscure. Our aim was to evaluate the impact of the regional emphysema score (RES) on a patient's overall survival, quality of life (QOL), and recovery of pulmonary function in stage I to II lung cancer. Between 1997 and 2009, a total of 1073 patients were identified and divided into two surgical groups-cancer in the emphysematous (group 1 [n = 565]) and nonemphysematous (group 2 [n = 435]) regions-and one nonsurgical group (group 3 [n = 73]). RES was derived from the emphysematous region and categorized as mild (≤5%), moderate (6%-24%), or severe (25%-60%). In group 1, patients with a moderate or severe RES experienced slight decreases in postoperative forced expiratory volume in 1 second, but increases in the ratio of forced expiratory volume in 1 second to forced vital capacity compared with those with a mild RES (p < 0.01); however, this correlation was not observed in group 2. Posttreatment QOL was lower in patients with higher RESs in all groups, mainly owing to dyspnea (p < 0.05). Cox regression analysis revealed that patients with a higher RES had significantly poorer survival in both surgical groups, with adjusted hazard ratios of 1.41 and 1.43 for a moderate RES and 1.63 and 2.04 for a severe RES, respectively; however, this association was insignificant in the nonsurgical group (adjusted hazard ratio of 0.99 for a moderate or severe RES). In surgically treated patients with cancer in the emphysematous region, RES is associated with postoperative changes in lung function. RES is also predictive of posttreatment QOL related to dyspnea in early-stage lung cancer. In both surgical groups, RES is an independent predictor of survival. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Editorial

NASA Astrophysics Data System (ADS)

2003-06-01

In December 2002 we announced some changes to Journal of Physics B: Atomic, Molecular and Optical Physics: an extended scope to highlight the wide range of articles published in the journal and a new definition of Letters to the Editor. As always, comments and suggestions are welcome and should be sent to jphysb@iop.org. Extended scope of J. Phys. B J. Phys. B covers all aspects of atomic, molecular and optical physics. We publish articles on the study of atoms, ions, molecules, condensates or clusters, from their structure and interactions with particles, photons, fields and surfaces to all aspects of spectroscopy. Quantum optics, non-linear optics, laser physics, astrophysics, plasma physics, chemical physics, optical cooling and trapping and other investigations where the objects of study are the elementary atomic, ionic or molecular properties of processes are also included. With the introduction of the BEC Matters! portal and IOP Select, J. Phys. B, one of the major contributors, offers authors of articles in this research area wider visibility and more flexible publication with the opportunity to display multimedia attachments or web links to key groups and results. The recent papers listed below reflect the wide scope of J. Phys. B: Calculation of cross sections for very low-energy hydrogen-antihydrogen scattering using the Kohn variational method E A G Armour and C W Chamberlain J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 22 (28 November 2002) L489-L494 Imaging the electron transfer reaction of Ne2+ with Ar using position-sensitive coincidence spectroscopy Sarah M Harper, Wan-Ping Hu and Stephen D Price J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 21 (14 November 2002) 4409-4423 Ultraviolet-infrared wavelength scalings for strong field induced L-shell emissions from Kr and Xe clusters Alex B Borisov, Xiangyang Song, Fabrizio Frigeni, Yang Dai, Yevgeniya Koshman, W Andreas Schroeder, Jack Davis, Keith Boyer and Charles K Rhodes J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 21 (14 November 2002) L461-L467 A Bose-Einstein condensate in an optical lattice J Hecker Denschlag, J E Simsarian, H Häffner, C McKenzie, A Browaeys, D Cho, K Helmerson, S L Rolston and W D Phillips J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 14 (28 July 2002) 3095-3110 Locality of a class of entangled states I R Senitzky J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 14 (28 July 2002) 3029-3039 Solitons and vortices in ultracold fermionic gases Tomasz Karpiuk, Miroslaw Brewczyk and Kazimierz Rzazewski J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 14 (28 July 2002) L315-L321 Stable islands in chaotic atom-optics billiards, caused by curved trajectories M F Andersen, A Kaplan, N Friedman and N Davidson J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 9 (14 May 2002) 2183-2190 Emission probability and photon statistics of a coherently driven mazer Jin Xiong and Zhi-Ming Zhang J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 9 (14 May 2002) 2159-2172 The Li+-H2 system in a rigid-rotor approximation: potential energy surface and transport coefficients I Røeggen, H R Skullerud, T H Løvaas and D K Dysthe J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 7 (14 April 2002) 1707-1725 The stochastic Gross-Pitaevskii equation C W Gardiner, J R Anglin and T I A Fudge J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 6 (28 March 2002) 1555-1582 Oxygen ion impurity in the TEXTOR tokamak boundary plasma observed and analysed by Zeeman spectroscopy J D Hey, C C Chu, S Brezinsek, Ph Mertens and B Unterberg J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 6 (28 March 2002) 1525-1553 Electron-hexafluoropropene (C3F6) scattering at intermediate energies Czeslaw Szmytkowski, Pawel Mozejko and Stanislaw Kwitnewski J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 5 (14 March 2002) 1267-1274 High-resolution investigations of C2 and CN optical emissions in laser-induced plasmas during graphite ablation S Acquaviva and M L De Giorgi J. Phys. B: At. Mol. Opt. Phys. Vol 35, No 4 (28 February 2002) 795-806 New definition of a Letter to the Editor A Letter to the Editor should present new results, likely to stimulate further research and be of interest to the wider atomic, molecular and optical physics community. Above all the results should be sufficiently new and important to merit rapid publication as a Letter, which implies accelerated refereeing procedures. This should be made clear either in the body of the Letter, if appropriate, or with a supporting cover letter from the author on submission to the journal. Letters will have an upper limit of eight journal pages and, as an additional quality check, two referees instead of one will be used to review them. The Board will be asked to make a final publication decision in the event of two conflicting reports. With these measures in place it is hoped that the important new results will receive the exposure they deserve as a Letter. If you have any questions or comments on this or anything relating to J. Phys. B please contact Nicola Gulley, Publisher, J. Phys. B (E-mail: jphysb@iop.org).

P-gp, MRP2 and OAT1/OAT3 mediate the drug-drug interaction between resveratrol and methotrexate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Yongming

The purpose of present study was to investigate the effect of resveratrol (Res) on altering methotrexate (MTX) pharmacokinetics and clarify the related molecular mechanism. Res significantly increased rat intestinal absorption of MTX in vivo and in vitro. Simultaneously, Res inhibited MTX efflux transport in MDR1-MDCK and MRP2-MDCK cell monolayers, suggesting that the target of drug interaction was MDR1 and MRP2 in the intestine during the absorption process. Furthermore, there was a significant decrease in renal clearance of MTX after simultaneous intravenous administration. Similarly, MTX uptake was markedly inhibited by Res in rat kidney slices and hOAT1/3-HEK293 cell, indicating that OAT1more » and OAT3 were involved in the drug interaction in the kidney. Additionally, concomitant administration of Res decreased cytotoxic effects of MTX in hOAT1/3-HEK293 cells, and ameliorated nephrotoxicity caused by MTX in rats. Conversely, intestinal damage caused by MTX was not exacerbated after Res treatment. In conclusion, Res enhanced MTX absorption in intestine and decreased MTX renal elimination by inhibiting P-gp, MRP2, OAT1 and OAT3 in vivo and in vitro. Res improved MTX-induced renal damage without increasing intestinal toxicity. - Highlights: • DDI between MTX and Res will occur when they are co-administered. • The first targets of the DDI are P-gp and MRP2 located in intestine. • The second targets of the DDI are OAT1 and OAT3 in kidney. • Res improved MTX-induced renal damage without increasing intestinal toxicity.« less

Obesity-induced hepatic hypoperfusion primes for hepatic dysfunction after resuscitated hemorrhagic shock.

PubMed

Matheson, Paul J; Hurt, Ryan T; Franklin, Glen A; McClain, Craig J; Garrison, R Neal

2009-10-01

Obese patients (BMI>35) after blunt trauma are at increased risk compared to non-obese for organ dysfunction, prolonged hospital stay, infection, prolonged mechanical ventilation, and mortality. Obesity and non-alcoholic fatty liver disease (NAFLD) produce a low grade systemic inflammatory response syndrome (SIRS) with compromised hepatic blood flow, which increases with body mass index. We hypothesized that obesity further aggravates liver dysfunction by reduced hepatic perfusion following resuscitated hemorrhagic shock (HEM). Age-matched Zucker rats (Obese, 314-519 g & Lean, 211-280 g) were randomly assigned to 4 groups (n = 10-12/group): (1) Lean-Sham; (2) Lean, HEM, and resuscitation (HEM/RES); (3) Obese-Sham; and (4) Obese-HEM/RES. HEM was 40% of mean arterial pressure (MAP) for 60 min; RES was return of shed blood/5 min and 2 volumes of saline/25 min. Hepatic blood flow (HBF) using galactose clearance, liver enzymes and complete metabolic panel were measured over 4 h after completion of RES. Obese rats had increased MAP, heart rate, and fasting blood glucose and BUN concentrations compared to lean controls, required less blood withdrawal (mL/g) to maintain 40% MAP, and RES did not restore BL MAP. Obese rats had decreased HBF at BL and during HEM/RES, which persisted 4 h post RES. ALT and BUN were increased compared to Lean-HEM/RES at 4 h post-RES. These data suggest that obesity significantly contributes to trauma outcomes through compromised vascular control or through fat-induced sinusoidal compression to impair hepatic blood flow after HEM/RES resulting in a greater hepatic injury. The pro-inflammatory state of NAFLD seen in obesity appears to prime the liver for hepatic ischemia after resuscitated hemorrhagic shock, perhaps intensified by insidious and ongoing hepatic hypoperfusion established prior to the traumatic injury or shock.

Evaluating uncertainty in predicting spatially variable representative elementary scales in fractured aquifers, with application to Turkey Creek Basin, Colorado

USGS Publications Warehouse

Wellman, Tristan P.; Poeter, Eileen P.

2006-01-01

Computational limitations and sparse field data often mandate use of continuum representation for modeling hydrologic processes in large‐scale fractured aquifers. Selecting appropriate element size is of primary importance because continuum approximation is not valid for all scales. The traditional approach is to select elements by identifying a single representative elementary scale (RES) for the region of interest. Recent advances indicate RES may be spatially variable, prompting unanswered questions regarding the ability of sparse data to spatially resolve continuum equivalents in fractured aquifers. We address this uncertainty of estimating RES using two techniques. In one technique we employ data‐conditioned realizations generated by sequential Gaussian simulation. For the other we develop a new approach using conditioned random walks and nonparametric bootstrapping (CRWN). We evaluate the effectiveness of each method under three fracture densities, three data sets, and two groups of RES analysis parameters. In sum, 18 separate RES analyses are evaluated, which indicate RES magnitudes may be reasonably bounded using uncertainty analysis, even for limited data sets and complex fracture structure. In addition, we conduct a field study to estimate RES magnitudes and resulting uncertainty for Turkey Creek Basin, a crystalline fractured rock aquifer located 30 km southwest of Denver, Colorado. Analyses indicate RES does not correlate to rock type or local relief in several instances but is generally lower within incised creek valleys and higher along mountain fronts. Results of this study suggest that (1) CRWN is an effective and computationally efficient method to estimate uncertainty, (2) RES predictions are well constrained using uncertainty analysis, and (3) for aquifers such as Turkey Creek Basin, spatial variability of RES is significant and complex.

The physical therapy clinical research network (PTClinResNet): methods, efficacy, and benefits of a rehabilitation research network.

PubMed

Winstein, Carolee; Pate, Patricia; Ge, Tingting; Ervin, Carolyn; Baurley, James; Sullivan, Katherine J; Underwood, Samantha J; Fowler, Eileen G; Mulroy, Sara; Brown, David A; Kulig, Kornelia; Gordon, James; Azen, Stanley P

2008-11-01

This article describes the vision, methods, and implementation strategies used in building the infrastructure for PTClinResNet, a clinical research network designed to assess outcomes for health-related mobility associated with evidence-based physical therapy interventions across and within four different disability groups. Specific aims were to (1) create the infrastructure necessary to develop and sustain clinical trials research in rehabilitation, (2) generate evidence to evaluate the efficacy of resistance exercise-based physical interventions designed to improve muscle performance and movement skills, and (3) provide education and training opportunities for present and future clinician-researchers and for the rehabilitation community at-large in its support of evidence-based practice. We present the network's infrastructure, development, and several examples that highlight the benefits of a clinical research network. We suggest that the network structure is ideal for building research capacity and fostering multisite, multiinvestigator clinical research projects designed to generate evidence for the efficacy of rehabilitation interventions.

Resveratrol Induces Cancer Cell Apoptosis through MiR-326/PKM2-Mediated ER Stress and Mitochondrial Fission.

PubMed

Wu, Haili; Wang, Yingying; Wu, Changxin; Yang, Peng; Li, Hanqing; Li, Zhuoyu

2016-12-14

Resveratrol (Res), a natural phytoalexin found in a variety of plants, has significant antitumor activity. Pyruvate kinase M2 (PKM2) has abnormally high expression in various tumor cells, and it has been implicated in the survival of tumors. However, whether and how Res inhibits PKM2 expression is poorly understood. In the present study, we found that treatment with Res inhibited cell proliferation and induced cell apoptosis. The IC 50 values of Res against DLD1, HeLa, and MCF-7 cells were 75 ± 4.54, 50 ± 3.65, and 50 ± 3.32 μM, respectively. To elucidate mechanisms underlying its antitumor activities, serial experiments were performed. Results showed that reduction of PKM2 expression in tumor cells by Res treatment increased the expression of ER stress and mitochondrial fission proteins but reduced cell viability and the levels of fusion proteins. These phenomena were reversed by artificial overexpression of PKM2. Quantitative analyses showed that the expression of microRNA-326 (miR-326) was increased upon Res treatment. Treatment with the miR-326 mimic reduced PKM2 expression, promoting recovery from ER stress and mitochondrial fission. Overall, these results demonstrate that miR-326/PKM2-mediated ER stress and mitochondrial dysfunction participate in apoptosis induced by Res. These results provide novel insight into the molecular mechanisms by which Res suppresses tumors and further support for the use of Res as an antitumor drug.

Vertically oriented arrays of ReS 2 nanosheets for electrochemical energy storage and electrocatalysis

DOE PAGES

Gao, Jian; Li, Lu; Tan, Jiawei; ...

2016-05-17

Here, transition-metal dichalcogenide (TMD) nanolayers show potential as high-performance catalysts in energy conversion and storage devices. Synthetic TMDs produced by chemical-vapor deposition (CVD) methods tend to grow parallel to the growth substrate. Here, we show that with the right precursors and appropriate tuning of the CVD growth conditions, ReS 2 nanosheets can be made to orient perpendicular to the growth substrate. This accomplishes two important objectives; first, it drastically increases the wetted or exposed surface area of the ReS 2 sheets, and second, it exposes the sharp edges and corners of the ReS 2 sheets. We show that these structuralmore » features of the vertically grown ReS 2 sheets can be exploited to significantly improve their performance as polysulfide immobilizers and electrochemical catalysts in lithium–sulfur (Li–S) batteries and in hydrogen evolution reactions (HER). After 300 cycles, the specific capacity of the Li–S battery with vertical ReS 2 catalyst is retained above 750 mA h g –1, with only ~0.063% capacity decay per cycle, much better than the baseline battery (without ReS 2), which shows ~0.184% capacity decay per cycle under the same test conditions. As a HER catalyst, the vertical ReS 2 provides very small onset overpotential (<100 mV) and an exceptional exchange-current density (~67.6 μA/cm 2), which is vastly superior to the baseline electrode without ReS 2.« less

Small volcanic eruptions and the stratospheric sulfate aerosol burden

NASA Astrophysics Data System (ADS)

Pyle, David M.

2012-09-01

Understanding of volcanic activity and its impacts on the atmosphere has evolved in discrete steps, associated with defining eruptions. The eruption of Krakatau, Indonesia, in August 1883 was the first whose global reach was recorded through observations of atmospheric phenomena around the world (Symons 1888). The rapid equatorial spread of Krakatau's ash cloud revealed new details of atmospheric circulation, while the vivid twilights and other optical phenomena were soon causally linked to the effects of particles and gases released from the volcano (e.g. Stothers 1996, Schroder 1999, Hamilton 2012). Later, eruptions of Agung, Bali (1963), El Chichón, Mexico (1982) and Pinatubo, Philippines (1991) led to a fuller understanding of how volcanic SO2 is transformed to a long-lived stratospheric sulfate aerosol, and its consequences (e.g. Meinel and Meinel 1967, Rampino and Self 1982, Hoffman and Rosen 1983, Bekki and Pyle 1994, McCormick et al 1995). While our ability to track the dispersal of volcanic emissions has been transformed since Pinatubo, with the launch of fleets of Earth-observing satellites (e.g. NASA's A-Train; ESA's MetOp) and burgeoning networks of ground-based remote-sensing instruments (e.g. lidar and sun-photometers; infrasound and lightning detection systems), there have been relatively few significant eruptions. Thus, there have been limited opportunities to test emerging hypotheses including, for example, the vexed question of the role of 'smaller' explosive eruptions in perturbations of the atmosphere—those that may just be large enough to reach the stratosphere (of size 'VEI 3', Newhall and Self 1982, Pyle 2000). Geological evidence, from ice-cores and historical eruptions, suggests that small explosive volcanic eruptions with the potential to transport material into the stratosphere should be frequent (5-10 per decade), and responsible for a significant proportion of the long-term time-averaged flux of volcanic sulfur into the stratosphere (Rampino and Self 1984, Pyle et al 1996, Self and Rampino 2012). But as yet, there is little evidence for the consequences of this scale of eruption for the climate system (Miles et al 2004), and few data against which to test simulations of stratospheric sulfur-injection 'geoengineering' scenarios of a similar scale and frequency (e.g. English et al 2012). A hint of the new volcano-observing capability came during the eruption of Eyjafjallajökull, Iceland. For a few days in April 2010 meteorological conditions, coupled with a dramatic increase in volcanic ash production, led to the wide dispersal of fine volcanic particles across northern Europe; an event which was widely tracked by ground-based and satellite-borne instruments, augmented by in situ measurements from balloons and aircraft (Bennett et al 2010, Flentje et al 2010, Harrison et al 2010, Stohl et al 2011). Despite the interest in Eyjafjallajökull at the time, this was, geologically, only a very modest eruption with limited sulfur emissions and an impact restricted mainly to the regional troposphere (e.g. Thomas and Prata 2011, Walker et al 2012). Then, in June 2011, a previously dormant volcano in north-east Africa began to erupt violently. Little is known about Nabro, which is a partially collapsed volcano that straddles the Eritrea-Ethiopia border, and has had no known historical activity (Wiart and Oppenheimer 2005). Despite the remote location, and lack of prior warning, the event and its aftermath were remarkably well captured by remote-sensing instruments, as demonstrated in the new letter by Sawamura et al (2012). Using both ground-based and satellite-borne laser-ranging (lidar) data, Sawamura et al (2012) were able to extract detailed information about the nature of the volcanic aerosol layer, and its spread around the globe. The eruption started strongly, with substantial ash plumes for the first 48 h, rising to 9-14 km altitude (Smithsonian Institution 2011, Bourassa et al 2012), that carried at least 1.3-1.5 Tg of SO2 (Krotkov et al 2011, Clarisse et al 2012). This was probably the largest sulfur yield from an explosive eruption since Pinatubo and Hudson in 1991 (Deshler et al 2006, Krotkov et al 2010). Within two weeks, volcanic aerosol had been detected at elevations of 15-20 km within the upper troposphere/lower stratosphere above north Africa and southern Eurasia; and within a month, the aerosol had been detected by lidar instruments on every continent in the northern hemisphere, from 20°-45°N. The aerosol, presumed to be dominated by sulfate, persisted for the period of observation (June-September 2011), and led to a small but significant stratospheric aerosol optical depth (AOD) perturbation (average ~0.02). While this is an order of magnitude lower than global AOD perturbations following the most significant eruptions of the 20th century (e.g. Stothers 1996), it is nonetheless substantially larger than estimates of the typical 'nonvolcanic' stratospheric aerosol background ( < 0.01, Deshler 2008). The Nabro eruption was a particularly interesting event, partly because it was unremarkable. Without remote-sensing measurements, this eruption would probably have passed with little notice; and the geological record of this event is likely to be modest. But now we know that events of this scale still have the potential to have a hemispheric impact on the stratosphere. In this case, as both Sawamura et al (2012) and Bourassa et al (2012) show, the strong Asian summer monsoon was probably responsible for the rapid lofting of the SO2 plume into the lower stratosphere, where it was able to react to form a fine sulfate aerosol with the potential to persist for some months. Similar arguments will pertain to other geological small—but sulfur-rich—volcanic events in the past, and this calls for a reassessment of our assumptions about the potential impact of small volcanic eruptions on the stratospheric sulfate aerosol burden. References Bekki S and Pyle J A 1994 A 2-dimensional modeling study of the volcanic eruption of Mount Pinatubo J. Geophys. Res. 99 18861-9 Bennett A J, Odams P, Edwards D and Arason P 2010 Monitoring of lightning from the April-May 2010 Eykafjallajökull volcanic eruption using a very low frequency lightning location network Environ. Res. Lett. 5 044013 Bourassa A E, Robock A, Randel W J, Deshler T, Rieger L A, Lloyd N D, Llewellyn E J and Degenstein D A 2012 Large volcanic aerosol load in the stratosphere linked to Asian monsoon transport Science 337 78-81 Clarisse L, Hurtmans D, Clerbaux C, Hadji-Lazaro J, Ngadi Y and Coheur P F 2012 Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI) Atmos. Meas. Technol. 5 581-94 Deshler T 2008 A review of global stratospheric aerosol: measurements, importance, life cycle and local stratospheric aerosol Atmos. Res. 90 223-32 Deshler T et al 2006 Trends in the nonvolcanic component of stratospheric aerosol over the period 1971-2004 J. Geophys. Res. 111 D01201 English J M, Toon O B and Mills M J 2012 Microphysical simulations of sulphur burdens from stratospheric sulphur geoengineering Atmos. Chem. Phys. 12 4775-93 Flentje H et al 2010 The Eyjafjallajökull eruption in April 2010—detection of volcanic plume using in situ measurements, ozone sondes and lidar-ceilometer profiles Atmos. Chem. Phys. 10 10085-92 Hamilton K 2012 Sereno Bishop, Rollo Russell, Bishop's Ring and the discovery of the 'Krakatoa easterlies' Atmos. Ocean 50 169-75 Harrison R G, Nicoll K A, Ulanowski Z and Mather T A 2010 Self-charging of the Eyjafjallajökull volcanic ash plume Environ. Res. Lett. 5 024004 Hoffman D J and Rosen J M 1983 Sulfuric acid droplet formation and growth in the stratosphere after the 1982 eruption of El Chichon Science 222 325-7 Krotkov N, Yang K and Carn S 2011 A-Train observations of Nabro (Eritrea) eruption on June 13-16, 2011 (http://aura.gsfc.nasa.gov/science/feature-20120305b.html, retrieved 23 July 2012) Krotkov N A, Schoeberl M R, Morris G A, Carn S and Yang K 2010 Dispersion and lifetime of the SO2 cloud from the August 2008 Kasatochi eruption J. Geophys. Res. 115 D00L20 McCormick M P, Thomason L W and Trepte C R 1995 Atmospheric effects of the Mt Pinatubo eruption Nature 373 399-404 Meinel A B and Meinel M P 1967 Volcanic sunset-glow stratum—origin Science 15 189 Miles G M, Grainger R G and Highwood E J 2004 The significance of volcanic eruption strength and frequency for climate Q. J. R. Met. Soc. 130 2361-76 Newhall C G and Self S 1982 The volcanic explosivity index (VEI): an estimate of explosive magnitude for historical volcanism J. Geophys. Res. 87 1231-8 Pyle D M 2000 Sizes of volcanic eruptions Encyclopedia of Volcanoes ed H Sigurdsson et al (New York: Academic) pp 263-70 Pyle D M, Beattie P D and Bluth G J S 1996 Sulphur emissions to the stratosphere from explosive volcanic eruptions Bull. Volcanol. 57 663-71 Rampino M R and Self S 1982 Historic eruptions of Tambora (1815), Krakatau (1883) and Agung (1963), their stratospheric aerosols and climatic impact Quat. Res. 18 127-43 Rampino M R and Self S 1984 Sulfur-rich volcanic eruptions and stratospheric aerosols Nature 310 677-9 Sawamura P et al 2012 Stratospheric AOD after the 2011 eruption of Nabro volcano measured by lidars over the Northern Hemisphere Environ. Res. Lett. 7 034013 Schroder W 1999 Were noctilucent clouds caused by the Krakatoa eruption? A case study of the research problems before 1885 Bull. Am. Meterol. Soc. 80 2081-5 Self S and Rampino M R 2012 The 1963-1964 eruption of Agung volcano (Bali, Indonesia) Bull. Volcanol. 74 1521-36 Smithsonian Institution 2011 Nabro. First historically observed eruption began 13 June 2011 Bull. Glob. Volcanism Netw. 36 (9) (www.volcano.si.edu/reports/bulletin/contents.cfm?issue=3609) Stohl A et al 2011 Determination of time- and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: the 2010 Eyjafjallajökull eruption Atmos. Chem. Phys. 11 4333-51 Stothers R B 1996 Major optical depth perturbations to the stratosphere from volcanic eruptions: pyrheliometric period 1881-1960 J. Geophys. Res. 101 3901-20 Symons G J (ed) 1888 The Eruption of Krakatoa and Subsequent Phenomena (London: Trubner and Co) Thomas H E and Prata A J 2011 Sulphur dioxide as a volcanic ash proxy during the April-May 2010 eruption of Eyjafjallajökull Atmos. Chem. Phys. 11 6871-80 Walker J C, Carboni E, Dudhia A and Grainger R G 2012 Improved detection of sulphur dioxide in volcanic plumes using satellite-based hyperspectral infrared measurements: application to the Eyjafjallajökull 2010 eruption J. Geophys. Res. 117 D00U16 Wiart P and Oppenheimer C 2005 Large magnitude silicic volcanism in north Afar: the Nabro volcanic range and Ma'alalta volcano Bull. Volcanol. 67 99-115

Optical Emissions of Sprite Streamers in Weak Electric Fields

NASA Astrophysics Data System (ADS)

Liu, N.; Pasko, V. P.

2004-12-01

Sprites commonly consist of large numbers of needle-shaped filaments of ionization [e.g., Gerken and Inan, JASTP, 65, 567, 2003] and typically initiate at altitudes 70-75 km in a form of upward and downward propagating streamers [Stanley et al., GRL, 26, 3201, 1999; Stenbaek-Nielsen et al., GRL, 27, 3829, 2000; McHarg et al., JGR, 107, 1364, 2002; Moudry et al., JASTP, 65, 509, 2003]. The strong electric fields E exceeding the conventional breakdown threshold field Ek are needed for initiation of sprite streamers from single electron avalanches and recent modeling studies indicate that streamers propagating in fields E>Ek experience strong acceleration and expansion in good agreement with the above cited observations [Liu and Pasko, JGR, 109, A04301, 2004]. The initiated streamers are capable of propagating in fields substantially lower than Ek [Allen and Ghaffar, J. Phys. D: Appl. Phys., 28, 331, 1995] and it is expected that a significant part of sprite optical output comes from regions with EEk). Additionally, the values of electric fields inside of the streamer channel are always well below Ek and since the excitation coefficients for optical emissions are very sensitive to the driving electric field magnitude most of the optical luminosity of streamers in this case arises from streamer tips, indicating that observed streamer filaments in many cases may be produced by time averaging of optical luminosity coming from localized regions around streamer tips as streamers move through an instrument's field of view. We will discuss pressure dependent differences of optical emissions at different sprite altitudes, and important similarities between observed sprite streamers and recent time resolved (<1 ns) imaging of laboratory streamers in point-to-plane discharge geometry conducted at ground and near ground pressures [van Veldhuizen et al., IEEE Trans. Plasma Sci., 30, 162, 2002; Yi and Williams, J. Phys. D. Appl. Phys., 35, 205, 2002].

Resveratrol and Cardiovascular Diseases

PubMed Central

Bonnefont-Rousselot, Dominique

2016-01-01

The increased incidence of cardiovascular diseases (CVDs) has stimulated research for substances that could improve cardiovascular health. Among them, resveratrol (RES), a polyphenolic compound notably present in grapes and red wine, has been involved in the “French paradox”. RES is known for its antioxidant and anti-inflammatory properties and for its ability to upregulate endothelial NO synthase (eNOS). RES was able to scavenge •OH/O2•− and peroxyl radicals, which can limit the lipid peroxidation processes. Moreover, in bovine aortic endothelial cells (BAEC) under glucose-induced oxidative stress, RES restored the activity of dimethylargininedimethylaminohydrolase (DDAH), an enzyme that degrades an endogenous inhibitor of eNOS named asymmetric dimethylarginine (ADMA). Thus, RES could improve •NO availability and decrease the endothelial dysfunction observed in diabetes. Preclinical studies have made it possible to identify molecular targets (SIRT-1, AMPK, Nrf2, NFκB…); however, there are limited human clinical trials, and difficulties in the interpretation of results arise from the use of high-dose RES supplements in research studies, whereas low RES concentrations are present in red wine. The discussions on potential beneficial effects of RES in CVDs (atherosclerosis, hypertension, stroke, myocardial infarction, heart failure) should compare the results of preclinical studies with those of clinical trials. PMID:27144581

Low-Frequency Noise in Layered ReS2 Field Effect Transistors on HfO2 and Its Application for pH Sensing.

PubMed

Liao, Wugang; Wei, Wei; Tong, Yu; Chim, Wai Kin; Zhu, Chunxiang

2018-02-28

Layered rhenium disulfide (ReS 2 ) field effect transistors (FETs), with thickness ranging from few to dozens of layers, are demonstrated on 20 nm thick HfO 2 /Si substrates. A small threshold voltage of -0.25 V, high on/off current ratio of up to ∼10 7 , small subthreshold swing of 116 mV/dec, and electron carrier mobility of 6.02 cm 2 /V·s are obtained for the two-layer ReS 2 FETs. Low-frequency noise characteristics in ReS 2 FETs are analyzed for the first time, and it is found that the carrier number fluctuation mechanism well describes the flicker (1/f) noise of ReS 2 FETs with different thicknesses. pH sensing using a two-layer ReS 2 FET with HfO 2 as a sensing oxide is then demonstrated with a voltage sensitivity of 54.8 mV/pH and a current sensitivity of 126. The noise characteristics of the ReS 2 FET-based pH sensors are also examined, and a corresponding detection limit of 0.0132 pH is obtained. Our studies suggest the high potential of ReS 2 for future low-power nanoelectronics and biosensor applications.

RES-loaded pegylated CS NPs: for efficient ocular delivery.

PubMed

Pandian, Saravanakumar; Jeevanesan, Vinoth; Ponnusamy, Chandrasekar; Natesan, Subramanian

2017-02-01

The objective of this study is to develop resveratrol (RES) loaded polyethylene glycols (PEGs) modified chitosan (CS) nanoparticles (NPs) by ionic gelation method for the treatment of glaucoma. While increasing the concentration of PEG, the particle size and polydispersity index of the formulations increased. Entrapment efficiency and RES loading (RL) of NPs decreased while increasing PEG concentration. The in vitro release of NPs showed an initial burst release of RES (45%) followed by controlled release. Osmolality of formulations revealed that the prepared NPs were iso-osmolar with the tear. Ocular tolerance of the NPs was evaluated using hen's egg test on the chorioallantoic membrane and it showed that the NPs were non-irritant. RES-loaded PEG-modified CS NPs shows an improved corneal permeation compared with RES dispersion. Fluorescein isothiocyanate loaded CS NPs accumulated on the surface of the cornea but the PEG-modified CS NPs crossed the cornea and reached retinal choroid. RES-loaded PEG-modified CS NPs reduced the intra-ocular pressure (IOP) by 4.3 ± 0.5 mmHg up to 8 h in normotensive rabbits. These results indicate that the developed NPs have efficient delivery of RES to the ocular tissues and reduce the IOP for the treatment of glaucoma.

Hierarchical architecture of ReS2/rGO composites with enhanced electrochemical properties for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Qi, Fei; Chen, Yuanfu; Zheng, Binjie; He, Jiarui; Li, Qian; Wang, Xinqiang; Lin, Jie; Zhou, Jinhao; Yu, Bo; Li, Pingjian; Zhang, Wanli

2017-08-01

Rhenium disulfide (ReS2), a two-dimensional (2D) semiconductor, has attracted more and more attention due to its unique anisotropic electronic, optical, mechanical properties. However, the facile synthesis and electrochemical property of ReS2 and its composite are still necessary to be researched. In this study, for the first time, the ReS2/reduced graphene oxide (rGO) composites have been synthesized through a facile and one-pot hydrothermal method. The ReS2/rGO composites exhibit a hierarchical, interconnected, and porous architecture constructed by nanosheets. As anode for lithium-ion batteries, the as-synthesized ReS2/rGO composites deliver a large initial capacity of 918 mAh g-1 at 0.2 C. In addition, the ReS2/rGO composites exhibit much better electrochemical cycling stability and rate capability than that of bare ReS2. The significant enhancement in electrochemical property can be attributed to its unique architecture constructed by nanosheets and porous structure, which can allow for easy electrolyte infiltration, efficient electron transfer, and ionic diffusion. Furthermore, the graphene with high electronic conductivity can provide good conductive passageways. The facile synthesis approach can be extended to prepare other 2D transition metal dichalcogenides semiconductors for energy storage and catalytic application.

Expanding Science Teacher Preparation: the Role of External Funding

NASA Astrophysics Data System (ADS)

Lindberg, John M.; Vokos, S.; Seeley, L.; Close, E.

2006-12-01

The Department of Physics and the School of Education at Seattle Pacific University are in the early stages of expanding the scope and reach of our science teacher preparation. We will describe how we are putting the puzzle together and our results to date. * Supported in part by NSF grant #ESI-0455796, NSF grant # DUE-0630460, NSF grant DUE-0310583, The Boeing Corporation, PhysTec and the SPU Science Initiative.

The Nature of Light: II. A Historical Survey from the Planck Era and Implications for Budding Physicists

ERIC Educational Resources Information Center

Oon, Pey Tee; Subramaniam, R.

2009-01-01

Following on from our previous article (Oon and Subramaniam 2009 "Phys. Educ." 44 384-91), here we trace ideas on the history of light from the Planck era to modern times. In particular, the seminal contributions of Planck, Einstein and de Broglie are highlighted. Some lesser known facets of the nature of light are also emphasized. It is stressed…

Optimism Predicts Positive Health in Repatriated Prisoners of War

DTIC Science & Technology

2014-09-08

of officer rank (93%), educated (M 16 years, SD 2), and approximately 72 years old (SD 6). Informed consent was obtained from each repatriate...total cholesterol to HDL cholesterol (5.9), HDL cholesterol (37 g/dl), glycosylated hemoglobin (7.1%), urine cortisol (25.7 g/g creatinine), urine...strength, nutritional status, fatigue, and overall phys- ical function (Waldo, 1996; Cooper, 2007). To assess grip strength, we used the Lafayette Hand

Thermodynamics of quantum spacetime histories

NASA Astrophysics Data System (ADS)

Smolin, Lee

2017-11-01

We show that the simplicity constraints, which define the dynamics of spin foam models, imply, and are implied by, the first law of thermodynamics, when the latter is applied to causal diamonds in the quantum spacetime. This result reveals an intimate connection between the holographic nature of gravity, as reflected by the Bekenstein entropy, and the fact that general relativity and other gravitational theories can be understood as constrained topological field theories. To state and derive this correspondence we describe causal diamonds in the causal structure of spin foam histories and generalize arguments given for the near horizon region of black holes by Frodden, Gosh and Perez [Phys. Rev. D 87, 121503 (2013); , 10.1103/PhysRevD.87.121503Phys. Rev. D 89, 084069 (2014); , 10.1103/PhysRevD.89.084069Phys. Rev. Lett. 107, 241301 (2011); , 10.1103/PhysRevLett.107.241301Phys. Rev. Lett.108, 169901(E) (2012)., 10.1103/PhysRevLett.108.169901] and Bianchi [arXiv:1204.5122.]. This allows us to apply a recent argument of Jacobson [Phys. Rev. Lett. 116, 201101 (2016).10.1103/PhysRevLett.116.201101] to show that if a spin foam history has a semiclassical limit described in terms of a smooth metric geometry, that geometry satisfies the Einstein equations. These results suggest also a proposal for a quantum equivalence principle.

Epitaxial growth of ReS2(001) thin film via deposited-Re sulfurization

NASA Astrophysics Data System (ADS)

Urakami, Noriyuki; Okuda, Tetsuya; Hashimoto, Yoshio

2018-02-01

In this paper, we present the formation of large-size rhenium disulfide (ReS2) films via the sulfurization of Re films deposited on sapphire substrates. The effects of sulfurization temperature and pressure on the crystal quality were investigated. A [001]-oriented single crystal of ReS2 films with 6 × 10 mm2 area was realized. By sulfurizing Re films at 1100 °C, ReS2 films with well-defined sharp interfaces to c-plane sapphire substrates could be formed. Below and above the sulfurization temperature of 1100 °C, incomplete sulfurization and film degradation were observed. The twofold symmetry of the monocrystalline in-plane structure composed of Re-Re bonds along with Re-S bonds pointed to a distorted 1T structure, indicating that this structure is the most stable atomic arrangement for ReS2. For a S/Re compositional ratio equal to or slightly lower than 2.0, characteristic Raman vibrational modes with the narrowest line widths were observed. The typical absorption peak of ReS2 can be detected at 1.5 eV.

Residual Deep Convolutional Neural Network Predicts MGMT Methylation Status.

PubMed

Korfiatis, Panagiotis; Kline, Timothy L; Lachance, Daniel H; Parney, Ian F; Buckner, Jan C; Erickson, Bradley J

2017-10-01

Predicting methylation of the O6-methylguanine methyltransferase (MGMT) gene status utilizing MRI imaging is of high importance since it is a predictor of response and prognosis in brain tumors. In this study, we compare three different residual deep neural network (ResNet) architectures to evaluate their ability in predicting MGMT methylation status without the need for a distinct tumor segmentation step. We found that the ResNet50 (50 layers) architecture was the best performing model, achieving an accuracy of 94.90% (+/- 3.92%) for the test set (classification of a slice as no tumor, methylated MGMT, or non-methylated). ResNet34 (34 layers) achieved 80.72% (+/- 13.61%) while ResNet18 (18 layers) accuracy was 76.75% (+/- 20.67%). ResNet50 performance was statistically significantly better than both ResNet18 and ResNet34 architectures (p < 0.001). We report a method that alleviates the need of extensive preprocessing and acts as a proof of concept that deep neural architectures can be used to predict molecular biomarkers from routine medical images.

When the brain does not adequately feel the body: Links between low resilience and interoception.

PubMed

Haase, Lori; Stewart, Jennifer L; Youssef, Brittany; May, April C; Isakovic, Sara; Simmons, Alan N; Johnson, Douglas C; Potterat, Eric G; Paulus, Martin P

2016-01-01

This study examined neural processes of resilience during aversive interoceptive processing. Forty-six individuals were divided into three groups of resilience Low (LowRes), high (HighRes), and normal (NormRes), based on the Connor-Davidson Resilience Scale (2003). Participants then completed a task involving anticipation and experience of loaded breathing during functional magnetic resonance imaging (fMRI) recording. Compared to HighRes and NormRes groups, LowRes self-reported lower levels of interoceptive awareness and demonstrated higher insular and thalamic activation across anticipation and breathing load conditions. Thus, individuals with lower resilience show reduced attention to bodily signals but greater neural processing to aversive bodily perturbations. In low resilient individuals, this mismatch between attention to and processing of interoceptive afferents may result in poor adaptation in stressful situations. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

NASA Astrophysics Data System (ADS)

Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

2018-05-01

Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

Terrestrial FeO Continuum Emission Observed in Sky Spectra

NASA Astrophysics Data System (ADS)

Slanger, Tom G.; Melchiorri, R.; Saran, D. V.

2011-01-01

The terrestrial continuum emission in the visible spectral region has often been studied by both astronomers and aeronomers, in order to clarify backgrounds and the nature of the emissions. New observations from the ESI spectrograph on the Keck II telescope, as well as from the OSIRIS/Odin spectrograph and orbiter, have established that a major component of the emission originates with the FeO molecule [Evans et al., 2010]. This quasi-continuum peaks at 5950 A and extends from 5000 A well into the infrared. The identity has been demonstrated by comparison with meteor trains and laboratory measurements [Jenniskens et al., 2000]. Early studies of the continuum show consistency with the FeO emission as presently observed [Gadsden and Marovich, 1973]. Analysis of spectra from Kitt Peak [Neugent and Massey, 2010] demonstrates the great similarity between FeO emission in a clean atmosphere and high pressure sodium lamp emission in a polluted atmosphere. This research was supported by NSF Aeronomy under Grant ATM-0637433 . Evans, W.F.J., et al., Geophys. Res. Lett. [in press, 2010] Gadsden, M. and E. Marovich, J. Atm. Terr. Phys., 35, 1601-1614 [1973] Jenniskens, P., et al., Earth, Moon and Planets, 82-83, 429-434 [2000] Neugent, K.F. and P. Massey, PASP [in press, 2010

Spin-symmetry conversion and internal rotation in high J molecular systems

NASA Astrophysics Data System (ADS)

Mitchell, Justin; Harter, William

2006-05-01

Dynamics and spectra of molecules with internal rotation or rovibrational coupling is approximately modeled by rigid or semi-rigid rotors with attached gyroscopes. Using Rotational Energy (RE)^1 surfaces, high resolution molecular spectra for high angular momentum show two distinct but related phenomena; spin-symmetry conversion and internal rotation. For both cases the high total angular momentum allows for transitions that would otherwise be forbidden. Molecular body-frame J-localization effects associated with tight energy level-clusters dominate the rovibronic spectra of high symmetry molecules, particularly spherical tops at J>10. ^2 The effects include large and widespread spin-symmetry mixing contrary to conventional wisdom^3 about weak nuclear moments. Such effects are discussed showing how RE surface plots may predict them even at low J. Classical dynamics of axially constrained rotors are approximated by intersecting rotational-energy-surfaces (RES) that have (J-S).B.(J-S) forms in the limit of constraints that do no work. Semi-classical eigensolutions are compared to those found by direct diagonalization. ^1 W.G Hater, in Handbook of Atomic, Molecular and Optical Physics, edited by G.W.F Drake (Springer, Germany 2006) ^2 W. G. Harter, Phys. Rev. A24,192-262(1981). ^3 G. Herzberg, Infrared and Raman Spectra (VanNostrand 1945) pp. 458,463.

Numerical Simulations of Laser-Driven Microflyer Plates

NASA Astrophysics Data System (ADS)

Colvin, Jeffrey D.; Frank, Alan M.; Lee, Ronald S.; Remington, Bruce A.

2000-10-01

Experiments conducted in the US and France have accelerated few-micron-thick foils of aluminum to velocities of 3 - 5 km/s using 25 - 50 J/cm^2 of 1-μm laser light (1,2). These microflyer plates are not too dissimilar in size and velocity from interplanetary dust particles (3). We are performing numerical simulations of these experiments with the 2-D radiation-hydrodynamics code LASNEX (4), incorporating a model for low-fluence electromagnetic wave reflection and absorption in metals, with the objective of determining the physical processes important to optimizing the flyer design. We will discuss our preliminary findings, including the efficacy of a thermal insulation layer and the role played by the substrate on which the flyer is mounted. (1) W.M. Trott, R.E. Setchell, and A.V. Farnsworth, Jr., in Shock Compression of Condensed Matter-1999, ed. M.D. Furnish, L.C. Chhabildas, and R.S. Hixson, AIP, 2000, pp. 1203-06. (2) J. L. Labaste, M. Doucet, and P. Joubert, in Shock Compression of Condensed Matter-1995, ed. S.C. Schmidt and W.C. Tao, AIP, 1996, pp. 1221-24. (3) W.W. Anderson and T.J. Ahrens, J. Geophys. Res. 99, 2063 (1994). (4) G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Controlled Fusion 2, 51 (1975).

Electronic Structure of Ethynyl Substituted Cyclobutadienes

NASA Astrophysics Data System (ADS)

Emmert, Frank Lee Emmert, III; Thompson, Stephanie J.; Slipchenko, Lyudmila V.

2011-06-01

We investigated the effects of ethynyl substitution on the electronic structure of cyclobutadiene. These species are involved in Bergman Cyclization reactionsand are possible intermediates in the formation of fullerenes and graphite sheets. Prediction of the electronic energy of cyclobutadiene is challenging for single-reference ab initio methods such as HF, MP2 or DFT because of Jahn-Teller distortions and the diradical character of the singlet state. We determined the vertical and adiabatic singlet-triplet energy splittings, the natural charges and spin densities in substituted cyclobutadienes, using the equations of motion spin flip coupled cluster with single and double excitations (EOM-SF-CCSD) method that accurately describes diradical states. The adiabatic singlet-triplet gaps decrease upon substituent addition, but the singlet state is always lower in energy. However, we found that the results are affected by spin-contamination of the reference state and deteriorate when an unrestricted HF reference is employed. O. L. Chapman, C. L. McIntosh, J. Pacansky, "Cyclobutadiene" J. Am. Chem. Soc. 1973, 95, (2), 614-617. N. S. Goroff, "Mechanism of Fullerene Formation." Acc. Chem. Res. 1996, 29, (2), 77-83. L.V. Slipchenko and A.I. Krylov, "Singlet-triplet gaps in diradicals by the Spin-Flip approach: A benchmark study", J. Chem. Phys. 2002, 117, 4694-4708.

Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

NASA Astrophysics Data System (ADS)

Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

2017-11-01

Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

Nearly axisymmetric hot plasmas in a highly rippled tokamak

NASA Astrophysics Data System (ADS)

Bellan, Paul

2002-11-01

Tokamak ohmic heating current flowing along toroidally rippled flux surfaces results in a poloidal torque. Since pressure gradients cannot offset torques, the torque drives plasma flows which convect plasma toroidally from ripple necks (high B_pol^2) to ripple bulges (low B_pol^2). Stagnation of the oppositely directed toroidal flows at the ripple bulges thermalizes the directed flow velocity ˜ B_pol/μ_0ρ , giving β _pol ˜1. These flows also convect frozen-in poloidal field lines which accumulate at the bulges enhancing the pinch force there and so reducing the bulge. Thus, a nearly axisymmetric β_pol ˜1 equilibrium is achieved using only a few TF coils. Particles bouncing in step between approaching flows will be Fermi accelerated to form a high energy tail. The ST tokamak magnetic mountain experiment [1] showed that, compared to a 1.8% ripple configuration, a 28% ripple configuration had four times the neutron production, and only a modest degradation of overall confinement; the former is consistent with the notion of Fermi acceleration of particles bouncing between colliding toroidal flows and the latter is consistent with ripple reduction due to toroidal convection of poloidal field lines. [1] W. Stodiek et al, Proc. 4th Intl. Conf. Plasma Phys. and Contr. Nuc. Fusion Res., (Madison, 1971), Vol. 1, p. 465

Detection of fissionable material in cargo containers using active neutron interrogation

NASA Astrophysics Data System (ADS)

Church, Jennifer

2006-10-01

Roughly 6 million cargo containers will be shipped to U.S. seaports in a single year, each container carrying up to 30 tons of freight in varied configurations. Highly enriched uranium and other fissionable material concealed inside these containers is a challenge for existing portal monitors, due in part to the attenuation of signals in the cargo. A system is currently being developed to overcome these challenges without slowing the flow of commerce through the port, keeping the likelihood of false-negative and false- positive detections to a minimum. The technique utilizes a neutron beam to induce fission, and a wall of plastic scintillators to detect subsequent delayed high-energy γ- rays after β-decay of the fission products Decay curves utilizing these delayed γ-rays with energies above 3 MeV are an efficient diagnostic. New experimental work using a 3-7 MeV broad spectrum neutron source will be presented and compared to simulations and past experimental results. This work is performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory contract No. W-7405-Eng-4, UCRL-ABS-219231. E.B.,orman et al., Nucl. Instr. Methods Phys. Res. A, 521, 608 (2004).

A First-Principles Analytical Theory for 2D Magnetic Reconnection in Electron and Hall Magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Chacon, L.; Simakov, A. N.; Zocco, A.

2007-12-01

Although the relevance of two-fluid effects in fast magnetic reconnection is well-known, (J. Birn et al., J. Geophys. Res., 106 (A3), 3715 (2001) a first-principles theory -- akin to Sweet and Parker's in resistive MHD -- has been elusive. Here, we present such a first principles steady-state analytical theory for electron MHD, (L. Chacón, A. N. Simakov, A. Zocco, Phys. Rev. Lett., submitted) and its extension to Hall MHD. (A. N. Simakov, L. Chacón, in preparation) The theory discretizes the extended MHD equations at the reconnection site, leading to a set of time-dependent ODEs. Their steady-state analysis, which describes the system at or around the point of maximum reconnection rate, provides predictions for the scaling of relevant quantities with the dissipation coefficients (e.g, resistivity and hyper-resistivity) and other relevant parameters. In particular, we will show that EMHD admits both elongated and open-X point configurations of the reconnection region, and that the reconnection rate can be shown not to scale explicitly with the dissipation parameters. This result is, to our knowledge, the first analytical confirmation of the possibility of fast magnetic reconnection in EMHD. In Hall MHD, the transition between resistive MHD and EMHD is studied, and scalings with the ion inertial length are obtained.

An empirical approach to the stopping power of solids and gases for ions from 3Li to 18Ar - Part II

NASA Astrophysics Data System (ADS)

Paul, Helmut; Schinner, Andreas

2002-10-01

This paper is a continuation of the work presented in Nucl. Instr. and Meth. Phys. Res. B 179 (2001) 299. Its aim is to produce a table of stopping powers by fitting empirical stopping values. Our database has been increased and we use a better fit function. As before, we treat solid and gaseous targets separately, but we now obtain results also for H 2 and He targets. Using an improved version of our program MSTAR, we can calculate the stopping power for any ion (3⩽ Z1⩽18) at specific energies from 0.001 to 1000 MeV/nucleon and for any element, mixture or compound contained in ICRU Report 49. MSTAR is available in the internet; it can be used as stand alone or built as a subroutine into other programs. Using a statistical program for comparing our fits with the experimental data, we find that MSTAR represents the data within 2% at high energy and within up to 20% (25% for gases) at the lowest energies. Fitting errors are 40-110% larger than experimental errors given by the authors. For some gas targets, MSTAR describes the data better than Ziegler's program TRIM.

Simulation study of disruption characteristics in KSTAR

NASA Astrophysics Data System (ADS)

Lee, Jongkyu; Kim, J. Y.; Kessel, C. E.; Poli, F.

2012-10-01

A detailed simulation study of disruption in KSTAR had been performed using the Tokamak Simulation Code(TSC) [1] during the initial design phase of KSTAR [2]. Recently, however, a partial modification in the structure of passive plate was made in relation to reduce eddy current and increase the efficiency of control of vertical position. A substantial change can then occur in disruption characteristics and plasma behavior during disruption due to changes in passive plate structure. Because of this, growth rate of vertical instability is expected to be increased and eddy current and its associated electomagnetic force are expected to be reduced. To check this in more detail, a new simulation study is here given with modified passive plate structure of KSTAR. In particular, modeling of vertical disruption that is vertical displacement event (VDE) was carried out. We calculated vertical growth rate for a drift phase of plasma and electromagnetic force acting on PFC structures and compared the results between in a new model and an old model. [4pt] [1] S.C. Jardin, N. Pomphrey and J. Delucia, J. Comp. Phys. 66, 481 (1986).[0pt] [2] J.Y. Kim, S.Y. Cho and KSTAR Team, Disruption load analysis on KSTAR PFC structures, J. Accel. Plasma Res. 5, 149 (2000).

A first-principles analytical theory for 2D magnetic reconnection in electron and Hall MHD.

NASA Astrophysics Data System (ADS)

Zocco, A.; Simakov, A. N.; Chacon, L.

2007-11-01

While the relevance of two-fluid effects in fast magnetic reconnection is well-known,ootnotetextJ. Birn et al., J. Geophys. Res., 106 (A3), pp. 3715--3719 (2001) a first-principles theory --akin to Sweet and Parker's in resistive MHD-- has been elusive. Here, we present such a first principles steady-state theory for electron MHD,ootnotetextL. Chac'on, A. N. Simakov, A. Zocco, Phys. Rev. Lett., submitted and its extension to Hall.ootnotetextA. N. Simakov, L. Chac'on, in preparation The theory discretizes the extended MHD equations at the reconnection site, leading to a set of time-dependent ODEs. Their steady-state analysis provides predictions for the scaling of relevant quantities with the dissipation coefficients (e.g, resistivity and hyper-resistivity) and other relevant parameters. In particular, we will show that EMHD admits both elongated and open-X point configurations of the reconnection region, and that the reconnection rate Ez can be shown not to scale explicitly with the dissipation parameters. This analytic result confirms earlier computational work on the possibility of fast (dissipation-independent) magnetic reconnection in EMHD. We have extended the EMHD results to Hall MHD, and have found a general scaling law for the reconnection rate (and associated length scales) that bridges the gap between resistive and EMHD.

Gestion de la douleur chronique par les infirmières des Groupes de médecine de famille

PubMed Central

Bergeron, Dave A; Bourgault, Patricia; Gallagher, Frances

2015-01-01

INTRODUCTION : Des milliers de personnes souffrent actuellement de douleur chronique (DC) pour laquelle la prise en charge s’avère souvent inadéquate. Au Québec, les infirmières qui oeuvrent dans les Groupes de médecine de famille (GMF) jouent un rôle clé dans le suivi des personnes aux prises avec des problèmes de santé chroniques dont la DC. OBJECTIFS : Cette étude a pour objectifs de décrire les activités réalisées par les infirmières œuvrant en GMF en lien avec la gestion de la douleur chez la clientèle souffrant de DC, ainsi que les barrières à ces activités. MÉTHODE : Un dispositif descriptif corrélationnel transversal de type enquête postale a été utilisé. La population accessible à l’étude comprend les infirmières qui figurent sur la liste des membres de l’Ordre des infirmières et infirmiers du Québec travaillant en GMF. L’ensemble des infirmières figurant sur cette liste ayant consenti à être contactées à leur domicile pour des fins de recherche ont été contactées. Un questionnaire postal auto-administré (Pain Management Activities Questionnaire) a été complété par 53 infirmières travaillant en GMF. RÉSULTATS : Les trois activités le plus souvent réalisées par les infirmières sont d’établir une relation thérapeutique avec le client; de discuter avec le médecin de l’efficacité des mesures thérapeutiques et de faire un enseignement personnalisé au client. Les infirmières ont la perception qu’elles rencontrent en moyenne 2,68 personnes par semaine qui souffrent de DC. La méconnaissance des interventions possibles en douleur (71,7%) et la non-disponibilité de l’information sur la gestion de la douleur (52,8%) constituent les principales barrières selon les infirmières sondées. CONCLUSION : Les infirmières au sein des GMF font actuellement peu d’activités en gestion de la DC probablement en raison du manque de reconnaissance de la DC. PMID:25848847

Evaluate the ability of PVP to inhibit crystallization of amorphous solid dispersions by density functional theory and experimental verify.

PubMed

Wang, Bing; Wang, Dandan; Zhao, Shan; Huang, Xiaobin; Zhang, Jianbin; Lv, Yan; Liu, Xiaocen; Lv, Guojun; Ma, Xiaojun

2017-01-01

In this study, we used density functional theory (DFT) to predict polymer-drug interactions, and then evaluated the ability of poly (vinyl pyrrolidone) (PVP) to inhibit crystallization of amorphous solid dispersions by experimental-verification. Solid dispersions of PVP/resveratrol (Res) and PVP/griseofulvin (Gri) were adopted for evaluating the ability of PVP to inhibit crystallization. The density functional theory (DFT) with the B3LYP was used to calculate polymer-drug and drug-drug interactions. Fourier transform infrared spectroscopy (FTIR) was used to confirm hydrogen bonding interactions. Polymer-drug miscibility and drug crystallinity were characterized by the modulated differential scanning calorimetry (MDSC) and X-ray powder diffraction (XRD). The release profiles were studied to investigate the dissolution advantage. DFT results indicated that E PVP-Res >E Res-Res (E: represents hydrogen bonding energy). A strong interaction was formed between PVP and Res. In addition, Fourier transform infrared spectroscopy (FTIR) analysis showed hydrogen bonding formed between PVP and Res, but not between PVP and Gri. MDSC and XRD results suggested that 70-90wt% PVP/Res and PVP/Gri solid dispersions formed amorphous solid dispersions (ASDs). Under the accelerated testing condition, PVP/Res dispersions with higher miscibility quantified as 90/10wt% were more stable than PVP/Gri dispersions. The cumulative dissolution rate of 90wt% PVP/Res dispersions still kept high after 90days storage due to the strong interaction. However, the cumulative dissolution rate of PVP/Gri solid dispersions significantly dropped because of the recrystallization of Gri. Copyright © 2016 Elsevier B.V. All rights reserved.

Southeast Regional Experiment Station

NASA Astrophysics Data System (ADS)

1994-08-01

This is the final report of the Southeast Regional Experiment Station project. The Florida Solar Energy Center (FSEC), a research institute of the University of Central Florida (UCF), has operated the Southeast Regional Experiment Station (SE RES) for the US Department of Energy (DOE) since September 1982. Sandia National Laboratories, Albuquerque (SNLA) provides technical program direction for both the SE RES and the Southwest Regional Experiment Station (SW RES) located at the Southwest Technology Development Institute at Las Cruces, New Mexico. This cooperative effort serves a critical role in the national photovoltaic program by conducting system evaluations, design assistance and technology transfer to enhance the cost-effective utilization and development of photovoltaic technology. Initially, the research focus of the SE RES program centered on utility-connected PV systems and associated issues. In 1987, the SE RES began evaluating amorphous silicon (a-Si) thin-film PV modules for application in utility-interactive systems. Stand-alone PV systems began receiving increased emphasis at the SE RES in 1986. Research projects were initiated that involved evaluation of vaccine refrigeration, water pumping and other stand-alone power systems. The results of this work have led to design optimization techniques and procedures for the sizing and modeling of PV water pumping systems. Later recent research at the SE RES included test and evaluation of batteries and charge controllers for stand-alone PV system applications. The SE RES project provided the foundation on which FSEC achieved national recognition for its expertise in PV systems research and related technology transfer programs. These synergistic products of the SE RES illustrate the high visibility and contributions the FSEC PV program offers to the DOE.

Defects, Tunneling, and EPR Spectra of Single-Molecule Magnets

DTIC Science & Technology

2003-01-01

Caranin, Phys. Rev. Lett. 87, 187203 (2001); Phys. Rev. B 65, 094423 (2002). 19. A. Cornia, R. Sessoli, L. Sorace, D. Gatteschi , A. L. Barra, and C...Phys. Rev. B 64, 184426 (2001). 25. A. Mukhin, B. Gorshunov, M. Dressel, C. Sangregorio. and D. Gatteschi , Phys. Rev. B 63, 214411 (2001). 26. W

Aerosol Formation In The Presence of Iodine and Ozone, Atmospheric Implications Based On Laboratory and Modelling Results

NASA Astrophysics Data System (ADS)

McFiggans, G.; Plane, J.; Joseph, M.; Casey, J.; Coe, H.; Williams, P.

The magnitude of the radiative forcing by aerosol depends on the number reaching optically active size (the direct effect) and the number that will activate into cloud droplets (the indirect effect). Aerosol number will depend on coagulation and depo- sitional loss processes in addition to the generation of nucleation mode particles to repopulate the ambient aerosol distribution. Great uncertainties surround the formation mechanisms of such atmospheric ultrafine particles, the dominant mechanisms changing with location and prevailing conditions (see e.g. Coe et al., 2000 &refs therein). It has been suggested that coastal ultrafine particle bursts measured under a wide variety of conditions (e.g. O Dowd et al., 1999) are related to iodocarbon compounds (Hoffmann et al., 2001) released by macroalgae in intertidal beds exposed during low tide (Carpenter et al., 1999). Since the particle bursts are only observed during daytime, it has been postulated that they are formed as a result of iodine photochemistry, probably involving higher iodine oxides. It has been known for some time that thick smokes are formed in laboratory kinetics exper- iments where iodine has been studied in the presence of ozone (Cox &Coker, 1983). The purpose of this study is to investigate whether the mechanism responsible for the laboratory phenomenon is a candidate for the formation of particles in the atmosphere. This study presents data from flow reactor experiments in which diiodomethane was photolysed in the presence of ozone under a variety of conditions. The formation of ultrafine particles and the subsequent evolution of the distribution was measured by a SMPS system. Such distributions were collected as a function of reactant concentra- tion, light intensity, relative humidity and a variety of other conditions and the results were found to be consistent and highly repeatable. A photochemical model has been developed to investigate the laboratory system. An existing gas phase model (McFiggans et al., 2000) with updated reaction kinetics (in- cluding a newly determined OIO photolysis cross-section) is coupled with a moving centre sectional consideration of coagulation and multicomponent condensation (Ja- 1 cobson, 1999). Several channels for the gaseous formation of the initial particle pre- cursor have been investigated. Ab initio studies have shown that a possible candidate for the gaseous precursor is di-iodine pentoxide and the photochemical model uses I2O5 polymerisation to initiate the particle formation mechanism. Multi-molecular clusters are allowed to form at the collision number by use of a polymerisation kernel, leading to a so-called barrierless nucleation system with all clusters stable. Clusters larger than a certain size are not explicitly considered and enter the evolving aerosol distribution. A comparison between modelled and experimental results will be pre- sented. Simulations at atmospheric concentrations will be used to discuss the implica- tions for atmospheric particle bursts. Coe H, Williams P., McFiggans G., Gallagher M., Beswick K., Bower K., Choularton T., J. Geophys. Res., 105, 26891, 2000 O Dowd, C., G. McFiggans, D. Creasey, L. Pirjola, C. Hoell, M. Smith, B. Allan, J. M. C. Plane, D. E. Heard, J. E. Lee, M. J. Pilling, M. Kulmala, Geophys. Res. Letts, 26, 1707, 1999 Hoffmann, T., C. O Dowd, J. H. Seinfeld, Geophys. Res. Letts, 28, 1949, 2001 Carpenter, L., W. Sturges, S. A. Penkett, P. S. Liss, B. Alicke, K. Hebestreit, U. Platt, J. Geophys. Res., 104, 1679, 1999 Cox, R. A. &G. B. Coker, J. Phys. Chem., 87, 4478, 1983 McFiggans, G., Plane, J.M.C., Allan, B.J, Carpenter, L.J, Coe, H, O Dowd, C., J. Geophys. Res., 104, 1679, 2000 Jacobson, M.Z., Fundamentals of Atmospheric Modelling, Cambridge Univ. Press, 1999 2

Links between extreme UV-radiation, total ozone, surface albedo and cloudiness: An analysis of 30 years of data from Switzerland and Austria

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Staehelin, J.; Weihs, P.; Vuilleumier, L.; Blumthaler, M.; Holawe, F.; Lindfors, A.; Maeder, J. A.; Simic, S.; Wagner, J. E.; Walker, D.; Ribatet, M.

2009-04-01

Since the discovery of anthropogenic ozone depletion in the early 1970s (e.g. Molina and Rowland, 1974; Farman et al., 1985) the interest in stratospheric ozone trends and solar UV-B increased within the scientific community and the general public because of the link between reduced total column ozone and increased UV-radiation doses. Stratospheric ozone (e.g. Koch et al., 2005) and erythemal UV-radiation (e.g. Rieder et al., 2008) in the northern mid-latitudes are characterized by strong temporal variability. Long-term measurements of UV-B radiation are rare and datasets are only available for few locations and most of these measurements do not provide spectral information on the UV part of the spectra. During strong efforts in the reconstruction of erythemal UV, datasets of past UV-radiation doses became available for several measurement sites all over the globe. For Switzerland and Austria reconstructed UV datasets are available for 3 measurement sites (Davos, Sonnblick and Vienna) (Lindfors and Vuilleumier, 2005; Rieder et al., 2008). The world's longest ozone time series dating back to 1926 is available from Arosa, Switzerland, and is discussed in detail by Staehelin et al. (1998a,b). Recently new tools from extreme value theory have been applied to the Arosa time series to describe extreme events in low and high total ozone (Rieder et al., 2009). In our study we address the question of how much of the extremes in UV-radiation can be attributed to extremes in total ozone, high surface albedo and cloudiness. An analysis of the frequency distributions of such extreme events for the last decades is presented to gain a better understanding of the links between extreme erythemal UV-radiation, total ozone, surface albedo and clouds. References: Farman, J. C., Gardiner, B. G., and Shanklin, J. D.: Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction, Nature, 315, 207-210, 1985. Koch, G., Wernli, H., Schwierz, C., Staehelin, J., and Peter, T.: A composite study on the structure and formation of ozone miniholes and minihights over central Europe, J. Geophys. Res., 32, doi:10.1029/2004GL022062, 2005. Lindfors, A., and Vuilleumier, L.: Erythemal UV at Davos (Switzerland), 1926-2003, estimated using total ozone, sunshine duration, and snow depth, J. Geophys. Res., 110, D02104, doi:10.1029/2004JD005231, 2005. Molina, M. J., and Rowland, F. S.: Stratospheric sink for chlorofluoromethans: Chlorine atom-catalysed destruction of ozone, Nature, 249, 810-812, 1974. Rieder, H.E., Holawe, F., Simic, S., Blumthaler, M., Krzyscin, J.W., Wagner J.E., Schmalwieser A.W., and Weihs, P.: Reconstruction of erythemal UV-doses for two stations in Austria: A comparison between alpine and urban regions, Atmos. Chem. Phys., 8, 6309-6323, 2008. Rieder, H.E., Staehelin, J., Maeder, J.A., Ribatet, M., Stübi, R., Weihs, P., Holawe, F., Peter, T., and Davison, A.C.: From ozone mini holes and mini highs towards extreme value theory: New insights from extreme events and non stationarity, submitted to J. Geophys. Res., 2009. Staehelin, J., Kegel, R., and Harris, N. R.: Trend analysis of the homogenized total ozone series of Arosa (Switzerland), 1929-1996, J. Geophys. Res., 103(D7), 8389-8400, doi:10.1029/97JD03650, 1998a. Staehelin, J., Renaud, A., Bader, J., McPeters, R., Viatte, P., Hoegger, B., Bugnion, V., Giroud, M., and Schill, H.: Total ozone series at Arosa (Switzerland): Homogenization and data comparison, J. Geophys. Res., 103(D5), 5827-5842, doi:10.1029/97JD02402, 1998b.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohapatra, Purusottam; Satapathy, Shakti Ranjan; Das, Dipon

Cigarette smoking is a key factor for the development and progression of different cancers including mammary tumor in women. Resveratrol (Res) is a promising natural chemotherapeutic agent that regulates many cellular targets including p21, a cip/kip family of cyclin kinase inhibitors involved in DNA damage-induced cell cycle arrest and blocking of DNA replication and repair. We have recently shown that cigarette smoke condensate (CSC) prepared from commercially available Indian cigarette can cause neoplastic transformation of normal breast epithelial MCF-10A cell. Here we studied the mechanism of Res mediated apoptosis in CSC transformed (MCF-10A-Tr) cells in vitro and in vivo. Resmore » mediated apoptosis in MCF-10A-Tr cells was a p21 dependent event. It increased the p21 protein expression in MCF-10A-Tr cells and MCF-10A-Tr cells-mediated tumors in xenograft mice. Res treatment reduced the tumor size(s) and expression of anti-apoptotic proteins (e.g. PI3K, AKT, NFκB) in solid tumor. The expressions of cell cycle regulatory (Cyclins, CDC-2, CDC-6, etc.), BER associated (Pol-β, Pol-δ, Pol-ε, Pol-η, RPA, Fen-1, DNA-Ligase-I, etc.) proteins and LP-BER activity decreased in MCF-10A-Tr cells but remain significantly unaltered in isogenic p21 null MCF-10A-Tr cells after Res treatment. Interestingly, no significant changes were noted in SP-BER activity in both the cell lines after Res exposure. Finally, it was observed that increased p21 blocks the LP-BER in MCF-10A-Tr cells by increasing its interaction with PCNA via competing with Fen-1 after Res treatment. Thus, Res caused apoptosis in CSC-induced cancer cells by reduction of LP-BER activity and this phenomenon largely depends on p21. - Highlights: • Resveratrol (Res) caused reduction of MCF-10A-Tr cell growth by inducing apoptosis. • Res caused cell cycle arrest and DNA damage in p21 dependent manner. • Res mediated LP-BER reduction in MCF-10A-Tr cells was a p21 dependent phenomenon. • Res inhibits BER and PI3K, AKT, and NFκB protein expressions in tumor and xenografts. • Res-induced-p21 inhibited DNA repair by modulating Fen-1 binding to PCNA complex.« less

Dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status

PubMed Central

Zhang, C.; Wang, L.; Zhao, X. H.; Chen, X. Y.; Yang, L.; Geng, Z. Y.

2017-01-01

Abstract This experiment was to evaluate the effect of dietary resveratrol (Res) supplementation (0, 400 mg/kg) on growth performance, meat quality, and muscle anaerobic glycolysis and antioxidant capacity of transported broilers. A total of 360 21-day-old male Cobb broilers was randomly allotted to 2 dietary treatments (Res-free group and Res group) with 12 replicates of 15 birds each. On the morning of d 42, after a 9-hour fast, 24 birds (2 birds of each replicate) were selected from the Res-free group and then equally placed into 2 crates, and the other 12 birds (one bird of each replicate) were selected from the Res group and then placed into the other crate. All birds in the 3 crates were transported according to the following protocols: 0-hour transport of birds in the Res-free group (control group), 3-hour transport of birds in the Res-free group (T group), and 3-hour transport of birds in the Res group (T + Res group). The results showed that Res not only improved feed conversion ratio (P < 0.05) but also tended to improve birds’ final body weight (P < 0.10). In the Res-free group, a 3-hour transport increased serum corticosterone concentration, muscle malondialdehyde (MDA) and lactate contents, and muscle lactate dehydrogenase (LDH) activity, while it decreased muscle glycogen content, total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-PX) activities (P < 0.05), which induced decreased breast meat quality (lower pH24h and higher drip loss and L*24 h, P < 0.05). Nevertheless, compared with the T group, Res increased muscle glycogen content and T-SOD and GSH-PX activities (P < 0.05 or P < 0.10), while it decreased muscle MDA content and LDH activity (P < 0.05), which is beneficial to the meat quality maintenance of transported broilers (lower drip loss, L*24 h, and higher pH24h, P < 0.05 or P < 0.10). This study provides the first evidence that dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers, possibly through decreasing the muscle anaerobic glycolysis metabolism and improving the muscle antioxidant capacity. PMID:28339929

Hypoglycemic depression of RES function.

PubMed

Buchanan, B J; Filkins, J P

1976-07-01

The intravascular removal rates of colloidal carbon and of biologically active endotoxin by the reticuloendothelial system (RES) were evaluated as a function of blood-glucose levels. There was a significant negative correlation of carbon clearance half time on blood glucose in both saline-treated and insulin-treated rats. Insulin hypoglycemia depressed RES carbon clearance with the maximal effect occurring at blood glucose values below 30 mg/dl. Insulin hypoglycemia also severely impaired the intravascular removal of endotoxin as evaluated by lethality bioassay in lead-sensitized rats. It is concluded that blood glucose may modulate RES phagocytic function and that the hypoglycemia of endotoxin shock may augment the shock state due to impairment of RES host defense clearance functions.

CeREs_VCLS_CubeSat_0002

NASA Image and Video Library

2018-04-10

A host of CubeSats, or small satellites, are undergoing the final stages of processing at Rocket Lab USA’s facility in Huntington Beach, California, for NASA’s first mission dedicated solely to spacecraft of their size. This will be the first launch under the agency’s new Venture Class Launch Services. Scientists, including those from NASA and various universities, began arriving at the facility in early April with spacecraft small enough to be a carry-on to be prepared for launch. A team from NASA’s Goddard Spaceflight Center in Greenbelt, Maryland, completed final checkouts of a CubeSat called the Compact Radiation Belt Explorer (CeREs), before placing the satellite into a dispenser to hold the spacecraft during launch inside the payload fairing. Among its missions, the satellite will examine the radiation belt and how electrons are energized and lost, particularly during events called microbursts — when sudden swarms of electrons stream into the atmosphere. This facility is the final stop for designers and builders of the CubeSats, but the journey will continue for the spacecraft. Rocket Lab will soon ship the satellites to New Zealand for launch aboard the company’s Electron orbital rocket on the Mahia Peninsula this summer. The CubeSats will be flown on an Educational Launch of Nanosatellites (ELaNa) mission to space through NASA’s CubeSat Launch Initiative. CeREs is one of the 10 ELaNa CubeSats scheduled to be a part of this mission.

Inventory of File sref_nmb.t03z.pgrb221.ctl.grib2

Science.gov Websites

006 10 m above ground UGRD analysis U-Component of Wind [m/s] ENS=low-res ctl 007 10 m above ground VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl 008 surface WEASD analysis Water Equivalent of -Component of Wind [m/s] ENS=low-res ctl 021 250 mb VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl

Inventory of File sref_nmb.t03z.pgrb132.ctl.grib2

Science.gov Websites

006 10 m above ground UGRD analysis U-Component of Wind [m/s] ENS=low-res ctl 007 10 m above ground VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl 008 surface WEASD analysis Water Equivalent of -Component of Wind [m/s] ENS=low-res ctl 021 250 mb VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl

Inventory of File sref_nmb.t03z.pgrb243.ctl.grib2

Science.gov Websites

006 10 m above ground UGRD analysis U-Component of Wind [m/s] ENS=low-res ctl 007 10 m above ground VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl 008 surface WEASD analysis Water Equivalent of -Component of Wind [m/s] ENS=low-res ctl 021 250 mb VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl

Inventory of File sref_nmb.t03z.pgrb216.ctl.grib2

Science.gov Websites

006 10 m above ground UGRD analysis U-Component of Wind [m/s] ENS=low-res ctl 007 10 m above ground VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl 008 surface WEASD analysis Water Equivalent of -Component of Wind [m/s] ENS=low-res ctl 021 250 mb VGRD analysis V-Component of Wind [m/s] ENS=low-res ctl

Resveratrol ameliorates chronic unpredictable mild stress-induced depression-like behavior: involvement of the HPA axis, inflammatory markers, BDNF, and Wnt/β-catenin pathway in rats.

PubMed

Yang, Xin-Hua; Song, Su-Qi; Xu, Yun

2017-01-01

Classic antidepressant drugs are modestly effective across the population and most are associated with intolerable side effects. Recently, numerous lines of evidence suggest that resveratrol (RES), a natural polyphenol, possesses beneficial therapeutic activity for depression. The aim of the present study was to explore whether RES exhibits an antidepressant-like effect in a depression model and to explore the possible mechanism. A depression model was established via chronic unpredictable mild stress (CUMS), after which the model rats in the RES and fluoxetine groups received a daily injection of RES or fluoxetine, respectively. The sucrose preference test, open field test, and forced swimming test were used to explore the antidepressant-like effects of RES. The activity of the hypothalamic-pituitary-adrenal (HPA) axis was evaluated by detecting the plasma corticosterone concentration and hypothalamic mRNA expression of corticotrophin-releasing hormone. The plasma interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) concentrations were measured by enzyme-linked immunosorbent assay. Hippocampal protein expression of brain-derived neurotrophic factor (BDNF) and the Wnt/β-catenin pathway were analyzed by western blot. The results showed that RES relieved depression-like behavior of CUMS rats, as indicated by the increased sucrose preference and the decreased immobile time. Rats that received RES treatment exhibited reduced plasma corticosterone levels and corticotrophin-releasing hormone mRNA expression in the hypothalamus, suggesting that the hyperactivity of the HPA axis in CUMS rats was reversed by RES. Moreover, after RES treatment, the rats exhibited increased plasma IL-6, CRP, and TNF-α concentrations. Furthermore, RES treatment upregulated the hippocampal protein levels of BDNF and the relative ratio of p-β-catenin/β-catenin while downregulating the relative ratio of p-GSK-3β/GSK-3β. Our findings suggest that RES improved depressive behavior in CUMS rats by downregulating HPA axis hyperactivity, increasing BDNF expression and plasma IL-6, CRP, and TNF-α concentrations, and regulating the hippocampal Wnt/β-catenin pathway.

Detection of colorectal masses in CT colonography: application of deep residual networks for differentiating masses from normal colon anatomy

NASA Astrophysics Data System (ADS)

Näppi, Janne J.; Hironaka, Toru; Yoshida, Hiroyuki

2018-02-01

Even though the clinical consequences of a missed colorectal cancer far outweigh those of a missed polyp, there has been little work on computer-aided detection (CADe) for colorectal masses in CT colonography (CTC). One of the problems is that it is not clear how to manually design mathematical image-based features that could be used to differentiate effectively between masses and certain types of normal colon anatomy such as ileocecal valves (ICVs). Deep learning has demonstrated ability to automatically determine effective discriminating features in many image-based problems. Recently, residual networks (ResNets) were developed to address the practical problems of constructing deep network architectures for optimizing the performance of deep learning. In this pilot study, we compared the classification performance of a conventional 2D-convolutional ResNet (2D-ResNet) with that of a volumetric 3D-convolutional ResNet (3D-ResNet) in differentiating masses from normal colon anatomy in CTC. For the development and evaluation of the ResNets, 695 volumetric images of biopsy-proven colorectal masses, ICVs, haustral folds, and rectal tubes were sampled from 196 clinical CTC cases and divided randomly into independent training, validation, and test datasets. The training set was expanded by use of volumetric data augmentation. Our preliminary results on the 140 test samples indicate that it is feasible to train a deep volumetric 3D-ResNet for performing effective image-based discriminations in CTC. The 3D-ResNet slightly outperformed the 2D-ResNet in the discrimination of masses and normal colon anatomy, but the statistical difference between their very high classification accuracies was not significant. The highest classification accuracy was obtained by combining the mass-likelihood estimates of the 2D- and 3D-ResNets, which enabled correct classification of all of the masses.

Equilibrium Structure and Vibrational Spectra of Sila-Adamantane

DTIC Science & Technology

2006-10-27

42, 3276 (1990); M. R. Pederson, K. A. Jackson, Phys. Rev. B. 43, 7312 ( 1991 ); M. R. Pederson, D. V. Porezag, J. Kortus, and D. C. Patton, Phys... Pankratov , Phys. Rev. B 68, 085310 (2003); P. H. Han, W. G. Schmidt, and F. Becstedt, Phys. Rev. B 72, 245425 (2005). [13] T. Yamada, T. Inoue, K. Yamada, N

Magnetotransport in Two Dimensional Electron Systems Under Microwave Excitation and in Highly Oriented Pyrolytic Graphite

DTIC Science & Technology

2012-01-01

Phys. Rev. Lett. 82, 2147 (1999). [89] Y. Zhang, Y. Tan, H. L. Stormer and P. Kim, Nature 438, 10 (2005). [90] J. W. McClure, Phys. Rev. 108, 612 (1957...Phys. 2, 595 (2006). [97] H. L. Stormer , J. P. Eisenstein, A. C. Gossard, W. Wiegmann, and K. Baldwin, Phys. Rev. Lett. 56, 85 (1985). [98] B. A...Sadowski, J. M. Schneider, and M. Potemski, J. Phys.: Cond. Matter 20, 454223 (2008). [108] W. Pan, J. S. Xia, H. L. Stormer , D. C. Tsui, C. L

The performances of standard and ResMed masks during bag-valve-mask ventilation.

PubMed

Lee, Hyoung Youn; Jeung, Kyung Woon; Lee, Byung Kook; Lee, Seung Joon; Jung, Yong Hun; Lee, Geo Sung; Min, Yong Il; Heo, Tag

2013-01-01

A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

Resveratrol Improves the Mitochondrial Function and Fertilization Outcome of Bovine Oocytes

PubMed Central

TAKEO, Shun; SATO, Daichi; KIMURA, Koji; MONJI, Yasunori; KUWAYAMA, Takehito; KAWAHARA-MIKI, Ryoka; IWATA, Hisataka

2013-01-01

The aim of the present study was to address the effect of resveratrol-mediated upregulation of sirtuin 1 (SIRT1) during oocyte maturation on mitochondrial function, the developmental ability of oocytes and on mechanisms responsible for blockage of polyspermic fertilization. Oocytes collected from slaughterhouse-derived ovaries were cultured in TCM-199 medium supplemented with 10% FCS and 0 or 20 µM resveratrol (Res). We examined the effect of Res on SIRT1 expression in in vitro-matured oocytes (Exp 1); fertilization and developmental ability (Exp 2); mitochondrial DNA copy number (Mt number), ATP content and mitochondrial membrane potential in matured oocytes (Exp 3); and the time required for proteinase to dissolve the zona pellucida following in vitro fertilization (as a marker of zona pellucida hardening), as well as on the distribution of cortical granules before and after fertilization (Exp 4). In Exp 1, the 20 µM Res treatment upregulated protein expression of SIRT1 in oocytes. In Exp 2, Res treatment improved the ratio of normal fertilization and the total cell number of blastocysts. In Exp 3, Res treatment significantly increased the ATP content in matured oocytes. Additionally, Res increased the overall Mt number and mitochondrial membrane potential, but the effect was donor-dependent. In Exp 4, Res-induced zona hardening improved the distribution and exocytosis of cortical granules after in vitro fertilization. In conclusion, Res improved the quality of oocytes by improving mitochondrial quantity and quality. In addition, Res added to the maturation medium enhanced SIRT1 protein expression in oocytes and improved fertilization via reinforcement of the mechanisms responsible for blockage of polyspermic fertilization. PMID:24390595

Development of renewable energy in China: Studying the experience and making recommendations for Russia

NASA Astrophysics Data System (ADS)

Lanshina, T. A.; Kulakov, A. V.

2017-07-01

The article reviews a state policy of China, due to which the country has managed to develop the world's largest sector of renewable energy sources (RES). Basic aspects of the formation and development of a comprehensive system of state support for the sector, i.e., the creation of scientific and technological advancement, stimulation of renewable energy equipment manufacturing, and support for RES electricity generation, are studied. Key programs implemented in specific stages are analyzed. Considerable attention is paid to the role and characteristics of foreign technology transfers. The dynamics of China's RES sector and the results of its rapid growth with the active participation of the state are researched. On the basis of the analysis, it is concluded that, in general, China's experience in development of RES is successful. Using the example of China, it is safe to say that, in the presence of a balanced state policy, a country is able to create in a decade a strong renewable energy equipment industry and to become a leader in the area of RES electricity generation. Specific features and main problems of the Russian RES sector are considered. On the basis of China's experience, recommendations for improving the state policy in RES are made for Russia. According to the authors, first of all, a sharp increase in state support for scientific research and development (R&D), pilot and demonstration projects, recognition of RES as a part of the fuel and energy sector at all tiers of authority, guarantees of state support for RES in the long run, ensuring access to long-term funds, and the creation of state programs supporting households participation in the distributed power generation are needed.

SIRT1 activation attenuates diastolic dysfunction by reducing cardiac fibrosis in a model of anthracycline cardiomyopathy.

PubMed

Cappetta, Donato; Esposito, Grazia; Piegari, Elena; Russo, Rosa; Ciuffreda, Loreta Pia; Rivellino, Alessia; Berrino, Liberato; Rossi, Francesco; De Angelis, Antonella; Urbanek, Konrad

2016-02-15

Doxorubicin (DOXO) is an effective anti-neoplastic drug but its clinical benefits are hampered by cardiotoxicity. Oxidative stress, apoptosis and myocardial fibrosis mediate the anthracycline cardiomyopathy. ROS trigger TGF-β pathway that activates cardiac fibroblasts promoting fibrosis. Myocardial stiffness contributes to diastolic dysfunction, less studied aspect of anthracycline cardiomyopathy. Considering the role of SIRT1 in the inhibition of the TGF-β/SMAD3 pathway, resveratrol (RES), a SIRT1 activator, might improve cardiac function by interfering with the development of cardiac fibrosis in a model of DOXO-induced cardiomyopathy. F344 rats received a cumulative dose of 15 mg/kg of DOXO in 2 weeks or DOXO+RES (DOXO and RES, 2.5mg/kg/day, concomitantly for 2 weeks and then RES alone for 1 more week). The effects of RES on cardiac fibroblasts were also tested in vitro. Along with systolic dysfunction, DOXO was also responsible of diastolic abnormalities. Myocardial stiffness correlated with fibroblast activation and collagen deposition. DOXO+RES co-treatment significantly improved ± dP/dt and, more interestingly, ameliorated end-diastolic pressure/volume relationship. Treatment with RES resulted in reduced fibrosis and fibroblast activation and, most importantly, the mortality rate was significantly reduced in DOXO+RES group. Fibroblasts isolated from DOXO+RES-treated rats, in which SIRT1 was upregulated, showed decreased levels of TGF-β and pSMAD3/SMAD3 when compared to cells isolated from DOXO-exposed hearts. Our findings reveal a key role of SIRT1 in supporting animal survival and functional parameters of the heart. SIRT1 activation by interfering with fibrogenesis can improve relaxation properties of myocardium and attenuate myocardial remodeling related to chemotherapy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

SCAPS, a two-dimensional ion detector for mass spectrometer

NASA Astrophysics Data System (ADS)

Yurimoto, Hisayoshi

2014-05-01

Faraday Cup (FC) and electron multiplier (EM) are of the most popular ion detector for mass spectrometer. FC is used for high-count-rate ion measurements and EM can detect from single ion. However, FC is difficult to detect lower intensities less than kilo-cps, and EM loses ion counts higher than Mega-cps. Thus, FC and EM are used complementary each other, but they both belong to zero-dimensional detector. On the other hand, micro channel plate (MCP) is a popular ion signal amplifier with two-dimensional capability, but additional detection system must be attached to detect the amplified signals. Two-dimensional readout for the MCP signals, however, have not achieve the level of FC and EM systems. A stacked CMOS active pixel sensor (SCAPS) has been developed to detect two-dimensional ion variations for a spatial area using semiconductor technology [1-8]. The SCAPS is an integrated type multi-detector, which is different from EM and FC, and is composed of more than 500×500 pixels (micro-detectors) for imaging of cm-area with a pixel of less than 20 µm in square. The SCAPS can be detected from single ion to 100 kilo-count ions per one pixel. Thus, SCAPS can be accumulated up to several giga-count ions for total pixels, i.e. for total imaging area. The SCAPS has been applied to stigmatic ion optics of secondary ion mass spectrometer, as a detector of isotope microscope [9]. The isotope microscope has capabilities of quantitative isotope images of hundred-micrometer area on a sample with sub-micrometer resolution and permil precision, and of two-dimensional mass spectrum on cm-scale of mass dispersion plane of a sector magnet with ten-micrometer resolution. The performance has been applied to two-dimensional isotope spatial distribution for mainly hydrogen, carbon, nitrogen and oxygen of natural (extra-terrestrial and terrestrial) samples and samples simulated natural processes [e.g. 10-17]. References: [1] Matsumoto, K., et al. (1993) IEEE Trans. Electron Dev. 40, 82-85. [2] Takayanagi et al. (1999) Proc. 1999 IEEE workshop on Charge-Coupled Devices and Advanced Image Sensors, 159-162. [3] Kunihiro et al. (2001) Nucl. Instrum. Methods Phys. Res. Sec. A 470, 512-519. [4] Nagashima et al. (2001) Surface Interface Anal. 31, 131-137. [5] Takayanagi et al. (2003) IEEE Trans. Electron Dev. 50, 70- 76. [6] Sakamoto and Yurimoto (2006) Surface Interface Anal. 38, 1760-1762. [7] Yamamoto et al. (2010) Surface Interface Anal. 42, 1603-1605. [8] Sakamoto et al. (2012) Jpn. J. Appl. Phys. 51, 076701. [9] Yurimoto et al. (2003) Appl. Surf. Sci. 203-204, 793-797. [10] Nagashima et al. (2004) Nature 428, 921-924. [11] Kunihiro et al. (2005) Geochim. Cosmochim. Acta 69, 763-773. [12] Nakamura et al. (2005) Geology 33, 829-832. [13] Sakamoto et al. (2007) Science 317, 231-233. [14] Greenwood et al. (2008) Geophys. Res. Lett., 35, L05203. [15] Greenwood et al. (2011) Nature Geoscience 4, 79-82. [16] Park et al. (2012) Meteorit. Planet. Sci. 47, 2070-2083. [17] Hashiguchi et al. (2013) Geochim. Cosmochim. Acta. 122, 306-323.

New particle formation events as a source for cloud condensation nuclei in an urban environment

NASA Astrophysics Data System (ADS)

Wonaschütz, Anna; Burkart, Julia; Wagner, Robert; Reischl, Georg; Steiner, Gerhard; Hitzenberger, Regina

2014-05-01

Nucleation and growth events have been observed in many remote, urban and rural environments. The new particles can contribute significantly to cloud condensation nuclei concentrations, after growing into the appropriate size range (Kerminen et al., 2012). Several studies have attempted to quantify this contribution (e.g. Asmi et al., 2011, Matsui et al., 2013), but only a limited number of them to date have used simultaneous measurements of CCN concentrations and particle size distributions for this purpose (e.g. Levin et al., 2012). In this study, a data set from an urban background station, consisting of 22 months of size distribution and 12 months of CCN concentration measurements (Burkart et al., 2011, Burkart et al., 2012) with 10 months of overlapping measurements is combined to explore the variability of CCN concentrations, their possible causes, and the contribution of nucleation and growth events to CCN concentrations. Consistent with observations in many other locations, nucleation and growth events occur on 30% of all days in spring and summer, on 11% of days in fall and on 4% of days in winter. This suggests a potentially large source of CCN from nucleation and growth events, particularly in the warm season. We acknowledge funding from FWF (Austrian Science Fund) P19515-N20 References: Asmi E., Kivekas, N., Kerminen, V. M., Komppula, M., Hyvarinen, A. P., Hatakka, J., Viisanen, Y., and Lihavainen, H.: Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010, Atmos. Chem. Phys., 11, 12959-12972, doi: 10.5194/acp-11-12959-2011, 2011 Burkart J., Steiner, G., Reischl, G., and Hitzenberger, R.: Long-term study of cloud condensation nuclei (CCN) acticvation of the atmospheric aerosol in Vienna, Atmos. Environ., 45, 5751-5759, doi: 10.1016/j.atmosenv.2011.07.022, 2011. Burkart J., Hitzenberger, R., Reischl, G., Bauer, H., Leder, K., and Puxbaum, H.: Activation of "synthetic ambient" aerosols - relation to chemical composition of particles < 100 nm, Atmos. Environ., 54, 583-591, doi: 10.1016/j.atmosenv.2012.01.063, 2012. Kerminen V.-M., Paramonov, M., Anttila, T., Riipinen, I., Fountoukis, C., Korhonen, H., Asmi, E., Laakso, L., Lihavainen, H., Swietlicki, E., Svenningsson, B., Asmi, A., Pandis, S. N., Kulmala, M., and Petäjä, T.: Cloud condensation nuclei production associated with atmospheric nucleation: a synthesis based on existing literature and new results, Atmos. Chem. Phys., 12, 12037-12059, doi: 10.5194/acp-12-12037-2012, 2012. Levin, E. J. T., Prenni, A. J., Petters, M. D., Kreidenweis, S. M., Sullivan, R. C., Atwood, S. A., Ortega, J., DeMott, P. J., and Smith, J. N.: An annual cycle of size-resolved aerosol hygroscopicity at a forested site in Colorado, J. Geophys. Res., 117, 06201, doi:10.1029/2011JD016854, 2012. Matsui, H., Koike, M., Kondo, Y., Takegawa, N., Wiedensohler, A., Fast, J. D., and Zaveri, R. A.: Impact of new particle formation on the concentrations of aerosols and cloud condensation nuclei around Beijing, J. Geophys. Res., 116, 19208, doi:10.1029/2011JD016025, 2011.

Fundamental properties of fracture and seismicity in a non extensive statistical physics framework.

NASA Astrophysics Data System (ADS)

Vallianatos, Filippos

2010-05-01

A fundamental challenge in many scientific disciplines concerns upscaling, that is, of determining the regularities and laws of evolution at some large scale, from those known at a lower scale. Earthquake physics is no exception, with the challenge of understanding the transition from the laboratory scale to the scale of fault networks and large earthquakes. In this context, statistical physics has a remarkably successful work record in addressing the upscaling problem in physics. It is natural then to consider that the physics of many earthquakes has to be studied with a different approach than the physics of one earthquake and in this sense we can consider the use of statistical physics not only appropriate but necessary to understand the collective properties of earthquakes [see Corral 2004, 2005a,b,c;]. A significant attempt is given in a series of works [Main 1996; Rundle et al., 1997; Main et al., 2000; Main and Al-Kindy, 2002; Rundle et al., 2003; Vallianatos and Triantis, 2008a] that uses classical statistical physics to describe seismicity. Then a natural question arises. What type of statistical physics is appropriate to commonly describe effects from fracture level to seismicity scale?? The application of non extensive statistical physics offers a consistent theoretical framework, based on a generalization of entropy, to analyze the behavior of natural systems with fractal or multi-fractal distribution of their elements. Such natural systems where long - range interactions or intermittency are important, lead to power law behavior. We note that this is consistent with a classical thermodynamic approach to natural systems that rapidly attain equilibrium, leading to exponential-law behavior. In the frame of non extensive statistical physics approach, the probability function p(X) is calculated using the maximum entropy formulation of Tsallis entropy which involves the introduction of at least two constraints (Tsallis et al., 1998). The first one is the classical normalization of p(X). The second one is based on the definition of the expectation value which has to be generalized to the "q-expectation value", according to the generalization of the entropy [Abe and Suzuki, 2003]. In order to calculate p(X) we apply the technique of Langrange multipliers maximizing an appropriate functional and leading tο maximization of the Tsallis entropy under the constraints on the normalization and the q-expectation value. It is well known that the Gutenberg-Richter (G-R) power law distribution has to be modified for large seismic moments because of energy conservation and geometrical reasons. Several models have been proposed, either in terms of a second power law with a larger b value beyond a crossover magnitude, or based on a magnidute cut-off using an exponential taper. In the present work we point out that the non extensivity viewpoint is applicable to seismic processes. In the frame of a non-extensive approach which is based on Tsallis entropy we construct a generalized expression of Gutenberg-Richter (GGR) law [Vallianatos, 2008]. The existence of lower or/and upper bound to magnitude is discussed and the conditions under which GGR lead to classical GR law are analysed. For the lowest earthquake size (i.e., energy level) the correlation between the different parts of elements involved in the evolution of an earthquake are short-ranged and GR can be deduced on the basis of the maximum entropy principle using BG statistics. As the size (i.e., energy) increases, long range correlation becomes much more important, implying the necessity of using Tsallis entropy as an appropriate generalization of BG entropy. The power law behaviour is derived as a special case, leading to b-values being functions of the non-extensivity parameter q. Furthermore a theoretical analysis of similarities presented in stress stimulated electric and acoustic emissions and earthquakes are discussed not only in the frame of GGR but taking into account a universality in the description of intrevent times distribution. Its particular form can be well expressed in the frame of a non extensive approach. This formulation is very different from an exponential distribution expected for simple random Poisson processes and indicates the existence of a nontrivial universal mechanism in the generation process. All the aforementioned similarities within stress stimulated electrical and acoustic emissions and seismicity suggests a connection with fracture phenomena at much larger scales implying that a basic general mechanism is "actively hidden" behind all this phenomena [Vallianatos and Triantis, 2008b]. Examples from S.Aegean seismicity are given. Acknowledgements: This work is partially supported by the "NEXT EARTH" project FP7-PEOPLE, 2009-2011 References Abe S. and Suzuki N., J. Goephys. Res. 108 (B2), 2113, 2003. Corral A., Phys. Rev. Lett. 92, 108501, 2004. Corral A., Nonlinear Proc. Geophys. 12, 89, 2005a. Corral A., Phys. Rev. E 71, 017101, 2005b. Corral A., Phys. Rev. Lett. 95, 028501, 2005c. Main I. G., Rev. of Geoph., 34, 433, 1996. Main I. G., O' Brien G. And Henderson R., J. Geoph. Res., 105, 6105, 2000. Main I. G. and Al-Kindy F. H., Geoph. Res. Let., 29, 7, 2002. Rundle J. B., Gross S., Klein W., Fergunson C. and Turcotte D., Tectonophysics, 277, 147-164, 1997. Rundle J. B., Turcotte D. L., Shcherbakov R., Klein W. and Sammis C., Rev. Geophys. 41, 1019, 2003. Tsallis C., J. Stat. Phys. 52, 479, 1988; See also http://tsallis.cat.cbpf.br/biblio.htm for an updated bibliography. Vallianatos, F., 2th IASME/WSEAS International Conference on Geology and Seismology (GES08), Cambridge, U.K, 2008. Vallianatos F. and Triantis D., Physica A, 387, 4940-4946, 2008a.

Chemical Reactions at the in vacuo Au/InP Interface.

DTIC Science & Technology

1987-07-25

Phys. C: Solid State Phys. 10, 4545 (1977). 2 A. Hiraki, K. Shuto, S. Kim, W. Kanmnura, and M. Iwami, Appl.Phys. Letts. 31, 611 (1977). 3. P.W. Chye ...Pelous, and P. Henoc, J.Appl.Phys. 52, 5112 (1981). 13. 1. Camlibel, A.K. Chin , F. Ermanis, M.A. DiGiuseppe, J.A. Lourenco and W.A. Bonner

Laboratory Simulations of Space Weathering of Asteroid Surfaces by Solar Wind Ions.

NASA Astrophysics Data System (ADS)

Miller, Kenneth A.; De Ruette, Nathalie; Harlow, George; Domingue, Deborah L.; Savin, Daniel Wolf

2014-06-01

Studies into the formation of the terrestrial planets rely on the analysis of asteroids and meteorites. Asteroids are solar system remnants from the planetary formation period. By characterizing their mineralogical composition we can better constrain the formation and evolution of the inner planets.Remote sensing is the primary means for studying asteroids. Sample return missions, such as Hayabusa, are complex and expensive, hence we rely on asteroid reflectance spectra to determine chemical composition. Links have been made and debated between meteorite classes and asteroid types [1, 2]. If such relationships can be confirmed, then meteorites would provide a low cost asteroid sample set for study. However, a major issue in establishing this link is the spectral differences between meteorite samples and asteroid surfaces. The most commonly invoked explanation for these differences is that the surfaces of asteroids are space weathered [2, 3]. The dominant mechanism for this weathering is believed to be solar-wind ion irradiation [2, 4, 5]. Laboratory simulations of space weathering have demonstrated changes in the general direction required to alter spectra from unweathered meteorite samples to asteroid observations [3, 6 -10], but many open questions remain and we still lack a comprehensive understanding. We propose to explore the alleged connection of ordinary chondrite (OC) meteorites to S-type asteroids through a series of systematic laboratory simulations of solar-wind space weathering of asteroid surface materials. Here we describe the issue in more detail and describe the proposed apparatus. [1] Chapman C. R. (1996) Meteorit. Planet. Sci., 31, 699-725. [2] Chapman C. R. (2004), Annu. Rev. Earth Planet. Sci., 32, 539-567. [3] Hapke B. (2001) J. Ge-ophys. Res., 106, 10039-10074. [4] Pieters C.M. et al. (2000) Meteorit. Planet. Sci., 35, 1101-1107. [5] Ver-nazza P. et al. (2009) Nature, 458, 993-995. [6] Stra-zulla G. et al. (2005) Icarus, 174, 31-35 (2005). [7] Brunetto R and Strazzulla G (2005) Icarus, 179, 265-273. [8] Marchi S et al. (2005) Astron. Astrophys., 443, 769-775. [9] Loeffler M. J. et al. (2009) J. Geo-phys. Res., 114, E03003. [10] Fu X. et al. (2012) Ica-rus, 219, 630-640

Revisiting the IAGOS-CARIBIC CO and O3 observations and their correlation in the UT/LS

NASA Astrophysics Data System (ADS)

Boenisch, Harald; Zahn, Andreas; Brenninkmeijer, Carl; Williams, Jonathan; Rauthe-Schöch, Armin; Scharffe, Dieter; van Velthoven, Peter

2017-04-01

The CARIBIC research project, the predecessor of the actual IAGOS-CARIBIC project, is divided into two distinct phases: 1997-2002 and 2005-2016. Here, we will present a reassessment of CO and O3 observed during IAGOS-CARIBIC. The distribution and particularly the tracer-tracer correlation of both species has been widely used as a diagnostic tool for UT/LS transport processes (e.g. Hoor et al., 2002 and 2004; Pan et al., 2004). Up to now, only the early phase of CARIBIC observations of CO and O3 has been applied for transport studies in the tropopause region (Zahn et al., 2000 and 2002). The focus of this work here will be on the variability of the CO-O3 distribution and correlation on seasonal and interannual timescales in the extratropics using the IAGOS-CARIBIC in-situ measurements of CO and O3 spanning a time period from 1997 to 2016 with more than 400 flights. For a more detailed analysis and understanding of the underlying transport processes, the observations will be interpreted in combination with meteorological reanalysis data sets. The distribution of CO and O3 will be analysed relative to different tropopause definitions (chemical, dynamical, thermal) and in different coordinate systems (e.g. equivalent latitude, potential temperature, potential vorticity and distance to the tropopause). Also, the role of static stability and the tropopause inversion layer (TIL) on the tracer distribution will be investigated. Hoor, P., H. Fischer, L. Lange, J. Lelieveld, and D. Brunner (2002), Seasonal variations of a mixing layer in the lowermost stratosphere as identified by the CO-O3 correlation from in situ measurements, J. Geophys. Res., 107(D5), 4044, doi:10.1029/2000JD000289. Hoor, P., C. Gurk, D. Brunner, M. I. Hegglin, H. Wernli, and H. Fischer (2004), Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT, Atmos. Chem. Phys., 4, 1427-1442. Pan, L. L., W. J. Randel, B. L. Gary, M. J. Mahoney, and E. J. Hintsa (2004), Definitions and sharpness of the extratropical tropopause: A trace gas perspective, J. Geophys. Res., 109, D23103, doi:10.1029/ 2004JD004982.

Long-term trends in the total electron content (TEC)

NASA Astrophysics Data System (ADS)

Laštovička, Jan

2017-04-01

The long-term trends in the total electron content (TEC) have very little been studied. Lean et al. (2011; J. Geophys. Res., 116, A00H04, doi:10.1029/2010JA016378) studied trends in TEC globally based on JPL maps for 1995-2010. However, their trends appear to be too positive, which is not plausible taking into account the trends in other ionospheric parameters. Therefore they prefer the less positive trends calculated under the assumption of the same level of solar activity in solar cycle minima 22/23 and 23/24. However, as it is now clear, this is not a correct assumption. Lastovicka (2013; J. Geophys. Res. Space Phys., 118, 3831-3835, doi:10.1002/jgra.50261) selected a region around Florence, Italy, as a region with available historical TEC data based on Faraday rotation measurements and remarkably larger than average trends in TEC by Lean et al. (2011). Historical data from Florence provide no trend in TEC. However, foF2 from Juliusruh provide slight negative trends for 1976-1996 but no trends for 1995-2010. Thus the question of reality of trends by Lean et al. (2011) remained open. Here we use TEC from GIM and JPL data for two European regions with high Lean's trends, regions around Florence and around Prague, using 10-14 LT medians, 1998-2015, yearly average values. A classical approach is applied. First a model of solar activity dependence of TEC is constructed separately for each region from all data. Then model data are subtracted from experimental data and analysis is made with residuals. This analysis shows that early data (1998-2001) are by several TECU lower than they should be according to solar activity, the year 2002 is intermediate and in 2003-2015 the data fit well a weak or rather no trend of TEC. The change in TEC data does not seem to be jump-like, it lasted at least a year, if not longer. Thus the positive TEC trends reported by Lean et al. (2011) appear to be affected by data problem; real trends are evidently less positive if any.

Pacific slab beneath northeast China revealed by regional and teleseismic waveform modeling

NASA Astrophysics Data System (ADS)

WANG, X.; Chen, Q. F.; Wei, S.

2015-12-01

Accurate velocity and geometry of the slab is essential for better understanding of the thermal, chemical structure of the mantle earth, as well as geodynamics. Recent tomography studies show similar morphology of the subducting Pacific slab beneath northeast China, which was stagnant in the mantle transition zone with thickness of more than 200km and an average velocity perturbation of ~1.5% [Fukao and Obayashi, 2013]. Meanwhile, waveform-modeling studies reveal that the Pacific slab beneath Japan and Kuril Island has velocity perturbation up to 5% and thickness up to 90km [Chen et al., 2007; Zhan et al., 2014]. These discrepancies are probably caused by the smoothing and limited data coverage in the tomographic inversions. Here we adopted 1D and 2D waveform modeling methods to study the fine structure of Pacific slab beneath northeast China using dense regional permanent and temporary broadband seismic records. The residual S- and P-wave travel time, difference between data and 1D synthetics, shows significant difference between the eastern and western stations. S-wave travel time residuals indicate 5-10s earlier arrivals for stations whose ray path lies within the slab, compared with those out of the slab. Teleseimic waveforms were used to rule out the major contribution of the possible low velocity structure above 200km. Furthermore, we use 2D finite-difference waveform modeling to confirm the velocity perturbation and geometry of the slab. Our result shows that the velocity perturbation in the slab is significantly higher than those reported in travel-time tomography studies. ReferencesChen, M., J. Tromp, D. Helmberger, and H. Kanamori (2007), Waveform modeling of the slab beneath Japan, J. Geophys. Res.-Solid Earth, 112(B2), 19, doi:10.1029/2006jb004394.Fukao, Y., and M. Obayashi (2013), Subducted slabs stagnant above, penetrating through, and trapped below the 660 km discontinuity, J. Geophys. Res.-Solid Earth, 118(11), 5920-5938, doi:10.1002/2013jb010466.Zhan, Z. W., D. V. Helmberger, and D. Z. Li (2014), Imaging subducted slab structure beneath the Sea of Okhotsk with teleseismic waveforms, Phys. Earth Planet. Inter., 232, 30-35, doi:10.1016/j.pepi.2014.03.008.

The Warming Hiatus, Natural Variability and Thermal Ocean Structure

NASA Astrophysics Data System (ADS)

Groth, A.; Moron, V.; Robertson, A. W.; Kondrashov, D. A.; Ghil, M.

2015-12-01

Long before the recent concern with the warming hiatus, Ghil and Vautard (1991, Nature) stated at the end of their abstract that "The oscillatory components [in global temperature time series] have combined (peak-to-peak) amplitudes of 0.2°C, and therefore limit our ability to predict whether the inferred secular warming of 0.005°C/yr will continue." Present capabilities of the advanced spectral methods introduced into the global warming problem by that paper permit us now to consider oscillatory aspects of natural variability in much greater detail. In a multivariate analysis of the upper-ocean thermal structure, we examine properties of the recent long-term changes and of the naturally occurring global-climate fluctuations on interannual-to-interdecadal time scales. M. Ghil and associates (Ghil and Vautard 1991; Plaut et al. 1995, Science; Ghil et al. 2002, Rev. Geophys.), among others, have argued that this natural variability has some regularity embedded into it. Although the existence of such regularity on the interannual time scale is fairly well established by now, evidence for similar regularity on decadal and interdecadal time scales is more difficult to establish, due to the shortness of instrumental temperature data. To identify spatio-temporal patterns, we rely on the method of multichannel singular spectrum analysis [M-SSA; see Ghil et al. (2002) for a review] and on its recent improvements that help separate distinct patterns (Groth and Ghil 2011, Phys. Rev. E; Groth and Ghil 2015, J. Climate). Results on the temperature field from the Simple Ocean Data Assimilation (SODA) reanalysis (Carton and Giese 2008, Mon. Wea. Rev.; Giese and Ray 2011, J. Geophys. Res.) will be shown and contrasted with results on the HadCRUT surface temperature dataset (Morice et al. 2012, J. Geophys. Res.). We will focus, in particular, on the robustness of the geographical distribution of long-term changes in both data sets and discuss the significance of superimposed natural regularities in the traditional context of red noise (Hasselmann 1976, Tellus A). Finally, we will discuss the extent to which these regularities could have contributed to the recent hiatus in the long-term changes, as predicted by Ghil and Vautard (1991).

The impacts of renewable energy policies on renewable energy sources for electricity generating capacity

NASA Astrophysics Data System (ADS)

Koo, Bryan Bonsuk

Electricity generation from non-hydro renewable sources has increased rapidly in the last decade. For example, Renewable Energy Sources for Electricity (RES-E) generating capacity in the U.S. almost doubled for the last three year from 2009 to 2012. Multiple papers point out that RES-E policies implemented by state governments play a crucial role in increasing RES-E generation or capacity. This study examines the effects of state RES-E policies on state RES-E generating capacity, using a fixed effects model. The research employs panel data from the 50 states and the District of Columbia, for the period 1990 to 2011, and uses a two-stage approach to control endogeneity embedded in the policies adopted by state governments, and a Prais-Winsten estimator to fix any autocorrelation in the panel data. The analysis finds that Renewable Portfolio Standards (RPS) and Net-metering are significantly and positively associated with RES-E generating capacity, but neither Public Benefit Funds nor the Mandatory Green Power Option has a statistically significant relation to RES-E generating capacity. Results of the two-stage model are quite different from models which do not employ predicted policy variables. Analysis using non-predicted variables finds that RPS and Net-metering policy are statistically insignificant and negatively associated with RES-E generating capacity. On the other hand, Green Energy Purchasing policy is insignificant in the two-stage model, but significant in the model without predicted values.

Vanishing Hall conductance in the phase-glass Bose metal at zero temperature

NASA Astrophysics Data System (ADS)

May-Mann, Julian; Phillips, Philip W.

2018-01-01

Motivated in part by numerical simulations [H. G. Katzgraber and A. P. Young, Phys. Rev. B 66, 224507 (2002), 10.1103/PhysRevB.66.224507; J. M. Kosterlitz and N. Akino, Phys. Rev. Lett. 81, 4672 (1998), 10.1103/PhysRevLett.81.4672; Phys. Rev. Lett. 81, 4672 (1998), 10.1103/PhysRevLett.81.4672] that reveal that the energy to create a defect in a gauge or phase glass scales as Lθ with θ <0 for two dimensions, thereby implying a vanishing stiffness, we reexamine the relevance of these kinds of models to the Bose metal in light of the new experiments [N. P. Breznay and Kapitulnik (unpublished); Y. Wang, I. Tamir, D. Shahar, and N. P. Armitage, arXiv:1708.01908 [cond-mat.supr-con

Bone metabolic responses to low energy availability achieved by diet or exercise in active eumenorrheic women.

PubMed

Papageorgiou, Maria; Martin, Daniel; Colgan, Hannah; Cooper, Simon; Greeves, Julie P; Tang, Jonathan C Y; Fraser, William D; Elliott-Sale, Kirsty J; Sale, Craig

2018-06-19

We aimed to explore the effects of low energy availability (EA)[15 kcal·kg lean body mass (LBM) -1 ·d -1 ] achieved by diet or exercise on bone turnover markers in active, eumenorrheic women. By using a crossover design, ten eumenorrheic women (VO 2 peak : 48.1 ± 3.3 ml·kg -1 ·min -1 ) completed all three, 3-day conditions in a randomised order: controlled EA (CON; 45 kcal·kgLBM -1 ·d -1 ), low EA through dietary energy restriction (D-RES; 15 kcal·kgLBM -1 ·d -1 ) and low EA through increasing exercise energy expenditure (E-RES; 15 kcal·kgLBM -1 ·d -1 ), during the follicular phase of three menstrual cycles. In CON, D-RES and E-RES, participants consumed diets providing 45, 15 and 45 kcal·kgLBM -1 ·d -1 . In E-RES only, participants completed supervised running sessions (129 ± 10 min·d -1 ) at 70% of their VO 2 peak that resulted in an exercise energy expenditure of 30 kcal·kg LBM -1 ·d -1 . Blood samples were collected at baseline (BASE) and at the end of the 3-day period (D6) and analysed for bone turnover markers (β-CTX and P1NP), markers of calcium metabolism (PTH, albumin-adjusted Ca, Mg and PO 4 ) and hormones (IGF-1, T 3 , insulin, leptin and 17β-oestradiol). In D-RES, P1NP concentrations at D6 decreased by 17% (BASE: 54.8 ± 12.7 μg·L -1 , D6: 45.2 ± 9.3 μg·L -1 , P < 0.001, d = 0.91) and were lower than D6 concentrations in CON (D6: 52.5 ± 11.9 μg·L -1 , P = 0.001). P1NP did not change significantly in E-RES (BASE: 55.3 ± 14.4 μg·L -1 , D6: 50.9 ± 15.8 μg·L -1 , P = 0.14). β-CTX concentrations did not change following D-RES (BASE: 0.48 ± 0.18 μg·L -1 , D6: 0.55 ± 0.17 μg·L -1 ) or E-RES (BASE: 0.47 ± 0.24 μg·L -1 , D6: 0.49 ± 0.18 μg·L -1 ) (condition × time interaction effect, P = 0.17). There were no significant differences in P1NP (P = 0.25) or β-CTX (P = 0.13) responses between D-RES and E-RES. Both conditions resulted in reductions in IGF-1 (-13% and - 23% from BASE in D-RES and E-RES, both P < 0.01) and leptin (-59% and - 61% from BASE in D-RES and E-RES, both P < 0.001); T 3 decreased in D-RES only (-15% from BASE, P = 0.002) and PO 4 concentrations decreased in E-RES only (-9%, P = 0.03). Low EA achieved through dietary energy restriction resulted in a significant decrease in bone formation but no change in bone resorption, whereas low EA achieved through exercise energy expenditure did not significantly influence bone metabolism. Both low EA conditions elicited significant and similar changes in hormone concentrations. Copyright © 2018. Published by Elsevier Inc.

DPEMC: A Monte Carlo for double diffraction

NASA Astrophysics Data System (ADS)

Boonekamp, M.; Kúcs, T.

2005-05-01

We extend the POMWIG Monte Carlo generator developed by B. Cox and J. Forshaw, to include new models of central production through inclusive and exclusive double Pomeron exchange in proton-proton collisions. Double photon exchange processes are described as well, both in proton-proton and heavy-ion collisions. In all contexts, various models have been implemented, allowing for comparisons and uncertainty evaluation and enabling detailed experimental simulations. Program summaryTitle of the program:DPEMC, version 2.4 Catalogue identifier: ADVF Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVF Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: any computer with the FORTRAN 77 compiler under the UNIX or Linux operating systems Operating system: UNIX; Linux Programming language used: FORTRAN 77 High speed storage required:<25 MB No. of lines in distributed program, including test data, etc.: 71 399 No. of bytes in distributed program, including test data, etc.: 639 950 Distribution format: tar.gz Nature of the physical problem: Proton diffraction at hadron colliders can manifest itself in many forms, and a variety of models exist that attempt to describe it [A. Bialas, P.V. Landshoff, Phys. Lett. B 256 (1991) 540; A. Bialas, W. Szeremeta, Phys. Lett. B 296 (1992) 191; A. Bialas, R.A. Janik, Z. Phys. C 62 (1994) 487; M. Boonekamp, R. Peschanski, C. Royon, Phys. Rev. Lett. 87 (2001) 251806; Nucl. Phys. B 669 (2003) 277; R. Enberg, G. Ingelman, A. Kissavos, N. Timneanu, Phys. Rev. Lett. 89 (2002) 081801; R. Enberg, G. Ingelman, L. Motyka, Phys. Lett. B 524 (2002) 273; R. Enberg, G. Ingelman, N. Timneanu, Phys. Rev. D 67 (2003) 011301; B. Cox, J. Forshaw, Comput. Phys. Comm. 144 (2002) 104; B. Cox, J. Forshaw, B. Heinemann, Phys. Lett. B 540 (2002) 26; V. Khoze, A. Martin, M. Ryskin, Phys. Lett. B 401 (1997) 330; Eur. Phys. J. C 14 (2000) 525; Eur. Phys. J. C 19 (2001) 477; Erratum, Eur. Phys. J. C 20 (2001) 599; Eur. Phys. J. C 23 (2002) 311]. This program implements some of the more significant ones, enabling the simulation of central particle production through color singlet exchange between interacting protons or antiprotons. Method of solution: The Monte Carlo method is used to simulate all elementary 2→2 and 2→1 processes available in HERWIG. The color singlet exchanges implemented in DPEMC are implemented as functions reweighting the photon flux already present in HERWIG. Restriction on the complexity of the problem: The program relying extensively on HERWIG, the limitations are the same as in [G. Marchesini, B.R. Webber, G. Abbiendi, I.G. Knowles, M.H. Seymour, L. Stanco, Comput. Phys. Comm. 67 (1992) 465; G. Corcella, I.G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson, M. Seymour, B. Webber, JHEP 0101 (2001) 010]. Typical running time: Approximate times on a 800 MHz Pentium III: 5-20 min per 10 000 unweighted events, depending on the process under consideration.

Chaotic and Bifurcating Nonlinear Systems Driven by Noise with Applications to Laser Dynamics

DTIC Science & Technology

1988-12-30

W. o. leich and M. 0. Scully, Phys. Rev. A . 37, 3010 (1988) and ibid, 1261 (1988), and references therein. 14. A . K. Dhara and S. V . G. Menon, J...Fronzoni, F. Moss, R. Mannella and P. V . E. McClintock. Phys. Rev. A 36. 834 (1987) 35. L. Fronzoni, F. Moss and P. V . E. McClintock, Phys. Rev. A . 36...1492 (1987). 36. V . Altares and G. Nicolis, Phys. Rev. A 37. 3630 (1988) 37. R. Lefever and JI Win. Turner. Phys. Rev. Lett. 56, 1631 (1986) 38. K

Relativistically induced transparency acceleration of light ions by an ultrashort laser pulse interacting with a heavy-ion-plasma density gradient

NASA Astrophysics Data System (ADS)

Sahai, Aakash A.; Tsung, Frank S.; Tableman, Adam R.; Mori, Warren B.; Katsouleas, Thomas C.

2013-10-01

The relativistically induced transparency acceleration (RITA) scheme of proton and ion acceleration using laser-plasma interactions is introduced, modeled, and compared to the existing schemes. Protons are accelerated with femtosecond relativistic pulses to produce quasimonoenergetic bunches with controllable peak energy. The RITA scheme works by a relativistic laser inducing transparency [Akhiezer and Polovin, Zh. Eksp. Teor. Fiz 30, 915 (1956); Kaw and Dawson, Phys. FluidsPFLDAS0031-917110.1063/1.1692942 13, 472 (1970); Max and Perkins, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.27.1342 27, 1342 (1971)] to densities higher than the cold-electron critical density, while the background heavy ions are stationary. The rising laser pulse creates a traveling acceleration structure at the relativistic critical density by ponderomotively [Lindl and Kaw, Phys. FluidsPFLDAS0031-917110.1063/1.1693437 14, 371 (1971); Silva , Phys. Rev. E1063-651X10.1103/PhysRevE.59.2273 59, 2273 (1999)] driving a local electron density inflation, creating an electron snowplow and a co-propagating electrostatic potential. The snowplow advances with a velocity determined by the rate of the rise of the laser's intensity envelope and the heavy-ion-plasma density gradient scale length. The rising laser is incrementally rendered transparent to higher densities such that the relativistic-electron plasma frequency is resonant with the laser frequency. In the snowplow frame, trace density protons reflect off the electrostatic potential and get snowplowed, while the heavier background ions are relatively unperturbed. Quasimonoenergetic bunches of velocity equal to twice the snowplow velocity can be obtained and tuned by controlling the snowplow velocity using laser-plasma parameters. An analytical model for the proton energy as a function of laser intensity, rise time, and plasma density gradient is developed and compared to 1D and 2D PIC OSIRIS [Fonseca , Lect. Note Comput. Sci.9783-540410.1007/3-540-47789-6_36 2331, 342 (2002)] simulations. We model the acceleration of protons to GeV energies with tens-of-femtoseconds laser pulses of a few petawatts. The scaling of proton energy with laser power compares favorably to other mechanisms for ultrashort pulses [Schreiber , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.97.045005 97, 045005 (2006); Esirkepov , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.92.175003 92, 175003 (2004); Silva , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.92.015002 92, 015002 (2004); Fiuza , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.215001 109, 215001 (2012)].

Spouse READI (Resilience Education and Deployment Information): Randomized Clinical Trial. Formerly Reintegration: The Role of Spouse Telephone BATTLEMIND Randomized Clinical Trial

DTIC Science & Technology

2014-04-01

families. Mil Behav Health 2013; 1(1): 22-30. 4 Aday, Lu Ann ; Andersen R. A framework for the study of access to medical care. Health Serv Res 1974...identifying and re -shaping negative and destructive thoughts), and support (Belle et al., 2006; Gottman, Gottman, & Atkins, 2011, Schulz et al...Research, Translation and Practice. University of Michigan Geriatrics Retreat, Human Research across the Translational Spectrum: From the Lab to the

Assessing changes in stratospheric mean age of air and fractional release using historical trace gas observations

NASA Astrophysics Data System (ADS)

Laube, Johannes; Bönisch, Harald; Engel, Andreas; Röckmann, Thomas; Sturges, William

2014-05-01

Large-scale stratospheric transport is pre-dominantly governed by the Brewer-Dobson circulation. Due to climatic change a long-term acceleration of this residual stratospheric circulation has been proposed (e.g. Austin et al.,2006). Observational evidence has revealed indications for temporary changes (e.g. Bönisch et al., 2011) but a confirmation of a significant long-term trend is missing so far (e.g. Engel et al., 2009). A different aspect is a possible long-term change in the break-down of chemically important species such as chlorofluorocarbons as proposed by Butchart et al. 2001. Recent studies show significant differences adding up to more than 20 % in the chlorine released from such compounds (Newman et al., 2007; Laube et al., 2013). We here use a data set of three long-lived trace gases, namely SF6, CF2Cl2, and N2O, as measured in whole-air samples collected during balloon and aircraft flights between 1975 and 2011, to assess changes in stratospheric transport and chemistry. For this purpose we utilise the mean stratospheric transit times (or mean ages of air) in combination with a measure of the chemical decomposition (i.e. fractional release factors). We also evaluate the influence of different trend correction methods on these quantities and explore their variability with latitude, altitude, and season. References Austin, J. & Li, F.: On the relationship between the strength of the Brewer-Dobson circulation and the age of stratospheric air, Geophys. Res. Lett., 33, L17807, 2006. Bönisch, H., Engel, A., Birner, Th., Hoor, P., Tarasick, D. W., and Ray, E. A.: On the structural changes in the Brewer-Dobson circulation after 2000, Atmos. Chem. Phys., 11, 3937-3948, 2011. Butchart, N. & Scaife, A. A. Removal of chlorofluorocarbons by increased mass exchange between the stratosphere and troposphere in a changing climate. Nature, 410, 799-802, 2001. Engel, A., Möbius, T., Bönisch, H., Schmidt, U., Heinz, R., Levin, I., Atlas, E., Aoki, S., Nakazawa, T., Sugawara, S., Moore, F., Hurst, D., Elkins, J., Schauffler, S., Andrews, A., and Boering, K.: Age of stratospheric air unchanged within uncertainties over the past 30 years, Nature Geoscience, 2, 28-31, 2009 Laube, J.C., Keil, A., Bönisch, H., Engel., A., Röckmann, T., Volk, C. M., and Sturges, W. T.: Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases, Atmos. Chem. Phys., 13, 2779-2791, 2013 Newman, P. A., Daniel, J. S., Waugh, D. W., and Nash, E. R.: A new formulation of equivalent effective stratospheric chlorine (EESC), Atmos. Chem. Phys., 7, 4537-4552, 2007.

Impact of Duality Violations on Spectral Sum Rule analyses

NASA Astrophysics Data System (ADS)

Catà, Oscar

2007-02-01

Recent sum rule analyses on the two-point correlator have led to significant discrepancies in the values found for the OPE condensates, most dramatically in the dimension eight condensate and to a lesser extent in the dimension six one [R. Barate et al., ALEPH Collaboration, Eur. Phys. J. C 4 (1998) 409; K. Ackerstaff et al., OPAL Collaboration, Eur. Phys. J. C 7 (1999) 571, arXiv:hep-ex/9808019; S. Peris, B. Phily and E. de Rafael, Phys. Rev. Lett. 86 (2001) 14, arXiv:hep-ph/0007338; S. Friot, D. Greynat and E. de Rafael, JHEP 0410 (2004) 043, arXiv:hep-ph/0408281; M. Davier, L. Girlanda, A. Hocker and J. Stern, Phys. Rev. D 58 (1998) 096014, arXiv:hep-ph/9802447; B.L. Ioffe and K.N. Zyablyuk, Nucl. Phys. A 687 (2001) 437, arXiv:hep-ph/0010089. K.N. Zyablyuk, Eur. Phys. J. C 38 (2004) 215, arXiv:hep-ph/0404230; J. Bijnens, E. Gamiz and J. Prades, JHEP 0110 (2001) 009, arXiv:hep-ph/0108240; C.A. Dominguez and K. Schilcher, Phys. Lett. B 581 (2004) 193, arXiv:hep-ph/0309285; J. Rojo and J. I. Latorre, JHEP 0401 (2004) 055, arXiv:hep-ph/0401047; V. Cirigliano, E. Golowich and K. Maltman, Phys. Rev. D 68 (2003) 054013, arXiv:hep-ph/0305118; S. Ciulli, C. Sebu, K. Schilcher and H. Spiesberger, Phys. Lett. B 595 (2004) 359, arXiv:hep-ph/0312212. S. Narison, arXiv:hep-ph/0412152]. Precise knowledge of these condensates is of relevance in kaon decays [M. Knecht, S. Peris and E. de Rafael, Phys. Lett. B 457 (1999) 227, arXiv:hep-ph/9812471; J.F. Donoghue and E. Golowich, Phys. Lett. B 478 (2000) 172, arXiv:hep-ph/9911309; M. Knecht, S. Peris and E. de Rafael, Phys. Lett. B 508 (2001) 117, arXiv:hep-ph/0102017] and therefore it seems mandatory to assess the actual impact of what is commonly neglected in spectral sum rules, most prominently the issue of duality violations. We will explicitly compute them in a toy model and show that they are a priori non-negligible.

The global impact of mineral dust on cloud droplet number concentration

NASA Astrophysics Data System (ADS)

Karydis, V.; Tsimpidi, A.; Bacer, S.; Pozzer, A.; Nenes, A.; Lelieveld, J.

2016-12-01

This study assesses the importance of mineral dust for cloud droplet formation by taking into account i) the adsorption of water on the surface of insoluble dust particles, ii) the coating of soluble material on the surface of mineral particles which augments their cloud condensation nuclei activity, and iii) the effect of dust on the inorganic aerosol concentrations through thermodynamic interactions with mineral cations. Simulations are carried out with the EMAC chemistry climate model that calculates the global atmospheric aerosol composition using the ISORROPIA-II thermodynamic equilibrium model and considers the gas phase interactions with K+-Ca2+-Mg2+-NH4+-Na+-SO42-NO3-Cl-H2O particle components. Emissions of the inert mineral dust and the reactive dust aerosol components are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide (Karydis et al., 2016). We have implemented the "unified dust activation parameterization" (Kumar et al., 2011; Karydis et al., 2011) to calculate the droplet number concentration by taking into account the inherent hydrophilicity from adsorption and the acquired hygroscopicity from soluble salts by dust particles. Our simulations suggest that mineral dust significantly increases the cloud droplet number concentration (CDNC) over the main deserts and the adjacent oceans. However, over polluted areas the CDNC decreases significantly in the presence of dust. Furthermore, we investigate the role of adsorption activation of insoluble aerosols and the mineral dust thermodynamic interactions with inorganic anions on the cloud droplet formation. The CDNC sensitivity to the emission load, chemical composition, and inherent hydrophilicity of mineral dust is also tested. ReferencesKarydis, et al. (2011). "On the effect of dust particles on global cloud condensation nuclei and cloud droplet number." J. Geophys. Res. Atmos. 116. Karydis, et al. (2016). "Effects of mineral dust on global atmospheric nitrate concentrations." Atmos. Chem. Phys. 16(3): 1491-1509. Kumar, et al. (2011). "Measurements of cloud condensation nuclei activity and droplet activation kinetics of wet processed regional dust samples and minerals." Atmos. Chem. Phys. Discuss. 11(4): 12561-12605.

Multi-Fluid Interpenetration Mixing in X-ray and Directly Laser driven ICF Capsule Implosions

NASA Astrophysics Data System (ADS)

Wilson, Douglas

2003-10-01

Mix between a surrounding shell and the fuel leads to degradation in ICF capsule performance. Both indirectly (X-ray) and directly laser driven implosions provide a wealth of data to test mix models. One model, the multi-fluid interpenetration mix model of Scannapieco and Cheng (Phys. Lett. A., 299, 49, 2002), was implemented in an ICF code and applied to a wide variety of experiments (e.g. J. D. Kilkenny et al., Proc. Conf Plasm. Phys. Contr. Nuc. Fus. Res. 3, 29(1988), P. Amendt, R. E. Turner, O. L. Landen, Phy. Rev. Lett., 89, 165001 (2002), or Li et al., Phy. Rev. Lett, 89, 165002 (2002)). With its single adjustable parameter fixed, it replicates well the yield degradation with increasing convergence ratio for both directly and indirectly driven capsules. Often, but not always the ion temperatures with mixing are calculated to be higher than in an unmixed implosion, agreeing with observations. Comparison with measured directly driven implosion yield rates ( from the neutron temporal diagnostic or NTD) shows mixing increases rapidly during the burn. The model also reproduces the decrease of the fuel "rho-r" with fill gas pressure, measured by observing escaping deuterons or secondary neutrons. The mix model assumes fully atomically mixed constituents, but when experiments with deuterated plastic layers and 3He fuel are modeled, less that full atomic mix is appropriate. Applying the mix model to the ablator - solid DT interface in indirectly driven ignition capsules for the NIF or LMJ suggests that the capsules will ignite, but that burn after ignition may be somewhat degraded. Situations in which the Scannapieco and Cheng model fails to agree with experiments can guide us to improvements or the development of other models. Some directly driven symmetric implosions suggest that in highly mixed situations, a higher value of the mix parameter may needed. Others show the model underestimating the fuel burn temperature. This work was performed by the Los Alamos National Laboratory under DOE contract number W-7405-Eng-36.

Observations on the Freezing of Supercooled Pollen Washing Water by a New Electrodynamic Balance

NASA Astrophysics Data System (ADS)

Tong, Haijie; Pope, Francis D.; Kalberer, Markus

2014-05-01

Primary biological particles can act as efficient ice nuclei (IN) by initiating freezing events at temperatures warmer than the homogenous freezing temperature [1, 2]. For example, pollen grain particles can trigger freezing events at temperatures as warm as -5 °C in the contact freezing mode [3]. More recently pollen residues, which are released by washing pollen grains in water, were also observed to act as efficient IN in the immersion mode [4, 5]. In this study we developed a new cold electrodynamic balance (CEDB) system and investigated the freezing properties of single particles of supercooled pollen washing water (SPWW). The EDB technique allows for a contact free measurement of freezing events. The phase of the particle (liquid or frozen solid) can be distinguished via measuring the Mie scattering signal from the particle. Furthermore the size of liquid (spherical) particles can be determined. The freezing events are characterized through the loss of the regular Mie scattering signal from the levitated droplet as it changes state from liquid to a frozen solid. The statistical freezing probabilities of SPWW were obtained in the temperature range: -15 to -40 °C. Each temperature measurement point consists of the analysis of 30-100 droplets. Preliminary conclusions are that SPWW is IN active in the immersion mode. Further discussion will focus on the temperature range of the IN activity, the important variables (other than temperature) for IN activity, other likely modes of IN activity, and the implications of these results in terms of the atmospheric relevance of SPWW. This study was supported by the NERC. We acknowledge Professor Jonathan Reid and James Davis from the University of Bristol for providing information of the design of the warm EDB system. References: [1] Möhler, O., et al. (2007) Biogeosciences, 4, 1059-1071. [2] Prenni, A. J., et al. (2009) Nat. Geosci., 2, 401-404. [3] Diehl, K., et al. (2002) Atmos. Res., 61, 125-133. [4] Pummer, B. G., et al. (2012) Atmos. Chem. Phys., 12, 2541-2550. [5] Augustin, S., et al. (2013) Atmos. Chem. Phys., 13, 10989-11003.

Theoretical study of the effect of the size of a high-energy proton beam of the Large Hadron Collider on the formation and propagation of shock waves in copper irradiated by 450-GeV proton beams

NASA Astrophysics Data System (ADS)

Ryazanov, A. I.; Stepakov, A. V.; Vasilyev, Ya. S.; Ferrari, A.

2014-02-01

The interaction of 450-GeV protons with copper, which is the material of the collimators of the Large Hadron Collider, has been theoretically studied. A theoretical model for the formation and propagation of shock waves has been proposed on the basis of the analysis of the energy released by a proton beam in the electronic subsystem of the material owing to the deceleration of secondary particles appearing in nuclear reactions induced by this beam on the electronic subsystem of the material. The subsequent transfer of the energy from the excited electronic subsystem to the crystal lattice through the electron-phonon interaction has been described within the thermal spike model [I.M. Lifshitz, M.I. Kaganov, and L.V. Tanatarov, Sov. Phys. JETP 4, 173 (1957); I.M. Lifshitz, M.I. Kaganov, and L.V. Tanatarov, At. Energ. 6, 391 (1959); K. Yasui, Nucl. Instrum. Methods Phys. Res., Sect. B 90, 409 (1994)]. The model of the formation of shock waves involves energy exchange processes between excited electronic and ionic subsystems of the irradiated material and is based on the hydrodynamic approximation proposed by Zel'dovich [Ya.B. Zel'dovich and Yu.P. Raizer, Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena (Nauka, Moscow, 1966; Dover, New York, 2002)]. This model makes it possible to obtain the space-time distributions of the main physical characteristics (temperatures of the ionic and electronic subsystems, density, pressure, etc.) in materials irradiated by high-energy proton beams and to analyze the formation and propagation of shock waves in them. The nonlinear differential equations describing the conservation laws of mass, energy, and momentum of electrons and ions in the Euler variables in the case of the propagation of shock waves has been solved with the Godunov scheme [S. K. Godunov, A.V. Zabrodin, M.Ya. Ivanov, A.N. Kraiko, and G.P. Prokopov, Numerical Solution of Multidimensional Problems in Gas Dynamics (Nauka, Moscow, 1976) [in Russian

Conformational Transformation of Five-Membered Rings: the Gas Phase Structure of 2-METHYLTETRAHYDROFURAN

NASA Astrophysics Data System (ADS)

Van, Vinh; Nguyen, Ha Vinh Lam; Stahl, Wolfgang

2015-06-01

2-Methyltetrahydrofuran (2-MeTHF) is a promising environmentally friendly solvent and biofuel component which is derived from renewable resources. Following the principles of Green Chemistry, 2-MeTHF has been evaluated in various fields like organometallics, metathesis, and biosynthesis on the way to more eco-friendly syntheses. Cyclopentane as the prototype of five-membered rings is well-known to exist as twist or envelope structures. However, the conformational analysis of its heterocyclic derivative 2-methyl-tetrahydrothiophene (MTTP) yielded two stable twist conformers and two envelope transition states. Here, we report on the heavy atom r_s structure of the oxygen-analog of MTTP, 2-MeTHF, studied by a combination of molecular beam Fourier transform microwave spectroscopy and quantum chemistry. One conformer of 2-MeTHF was observed and highly accurate molecular parameters were determined using the XIAM program. In addition, all 13C-isotopologues were assigned in natural abundance of 1%. A structural determination based on the r_s positions of all carbon atoms was achieved via Kraitchman's equations. The methyl group in 2-MeTHF undergoes internal rotation and causes A-E splittings of the rotational lines. The barrier was calculated to be 1142 wn at the MP2/6-311++G(d,p) level of theory, which is rather high. Accordingly, narrow A-E splittings could be observed for only a few transitions. However, the barrier height could be fitted while the angles between the internal rotor axis and the principal axes of inertia were taken from the experimental geometry. V. Pace, P. Hoyos, L. Castoldi, P. Domínguez de María, A. R. Alcántara, ChemSusChem 5 (2012), 1369-1379. a) D. F. Aycock, Org. Process Res. Dev. 11 (2007),156-159. b) M. Smoleń, M. Kȩdziorek, K. Grela, Catal. Commun. 44 (2014), 80-84. V. Van, C. Dindic, H.V.L. Nguyen, W. Stahl, ChemPhysChem 16 (2015), 291-294. H. Hartwig, H. Dreizler, Z. Naturforsch. A 51 (1996), 923-932. J. Kraitchman, Am. J. Phys. 21 (1953), 17-24.

RES-E Support Policies In The Baltic States: Development Aspect (Part I)

NASA Astrophysics Data System (ADS)

Bobinaite, V.; Priedite, I.

2015-02-01

Despite quite similar conditions (natural resources) for electricity production from renewable energy sources (RES-E) in three Baltic States (Estonia, Latvia and Lithuania), significant differences exist in these countries as to the RES-E production volume. In Latvia this volume is the highest, while in Estonia and Lithuania it is half as high. One of the factors that determine the RES-E production volumes is support policies, which in the Baltic States are different. The main objective of this work was to analyze and compare these support policies. The results have shown that for rapid RES-E development the most effective policy is to be market-oriented (as in Estonia), whereas for more stable development such policy should be producer-oriented (as in Lithuania).

Resveratrol cocrystals with enhanced solubility and tabletability.

PubMed

Zhou, Zhengzheng; Li, Wanying; Sun, Wei-Jhe; Lu, Tongbu; Tong, Henry H Y; Sun, Changquan Calvin; Zheng, Ying

2016-07-25

Two new 1:1 cocrystals of resveratrol (RES) with 4-aminobenzamide (RES-4ABZ) and isoniazid (RES-ISN) were synthesized by liquid assisted grinding (LAG) and rapid solvent removal (RSR) methods using ethanol as solvent. Their physiochemical properties were characterized using PXRD, DSC, solid state and solution NMR, FT-IR, and HPLC. Pharmaceutically relevant properties, including tabletability, solubility, intrinsic dissolution rate, and hygroscopicity, were evaluated. Temperature-composition phase diagram for RES-ISN cocrystal system was constructed from DSC data. Both cocrystals show higher solubility than resveratrol over a broad range of pH. They are phase stable and non-hygroscopic even under high humidity conditions. Importantly, both cocrystals exhibit improved solubility and tabletability compared with RES, which make them more suitable candidates for tablet formulation development. Copyright © 2016 Elsevier B.V. All rights reserved.

The wheat Lr34 multipathogen resistance gene confers resistance to anthracnose and rust in sorghum.

PubMed

Schnippenkoetter, Wendelin; Lo, Clive; Liu, Guoquan; Dibley, Katherine; Chan, Wai Lung; White, Jodie; Milne, Ricky; Zwart, Alexander; Kwong, Eunjung; Keller, Beat; Godwin, Ian; Krattinger, Simon G; Lagudah, Evans

2017-11-01

The ability of the wheat Lr34 multipathogen resistance gene (Lr34res) to function across a wide taxonomic boundary was investigated in transgenic Sorghum bicolor. Increased resistance to sorghum rust and anthracnose disease symptoms following infection with the biotrophic pathogen Puccinia purpurea and the hemibiotroph Colletotrichum sublineolum, respectively, occurred in transgenic plants expressing the Lr34res ABC transporter. Transgenic sorghum lines that highly expressed the wheat Lr34res gene exhibited immunity to sorghum rust compared to the low-expressing single copy Lr34res genotype that conferred partial resistance. Pathogen-induced pigmentation mediated by flavonoid phytoalexins was evident on transgenic sorghum leaves following P. purpurea infection within 24-72 h, which paralleled Lr34res gene expression. Elevated expression of flavone synthase II, flavanone 4-reductase and dihydroflavonol reductase genes which control the biosynthesis of flavonoid phytoalexins characterized the highly expressing Lr34res transgenic lines 24-h post-inoculation with P. purpurea. Metabolite analysis of mesocotyls infected with C. sublineolum showed increased levels of 3-deoxyanthocyanidin metabolites were associated with Lr34res expression, concomitant with reduced symptoms of anthracnose. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Inhibition of protease-resistant prion protein formation by porphyrins and phthalocyanines

PubMed Central

Caughey, Winslow S.; Raymond, Lynne D.; Horiuchi, Motohiro; Caughey, Byron

1998-01-01

A central aspect of pathogenesis in the transmissible spongiform encephalopathies or prion diseases is the conversion of normal protease-sensitive prion protein (PrP-sen) to the abnormal protease-resistant form, PrP-res. Here we identify porphyrins and phthalocyanines as inhibitors of PrP-res accumulation. The most potent of these tetrapyrroles had IC50 values of 0.5–1 μM in scrapie-infected mouse neuroblastoma (ScNB) cell cultures. Inhibition was observed without effects on protein biosynthesis in general or PrP-sen biosynthesis in particular. Tetrapyrroles also inhibited PrP-res formation in a cell-free reaction composed predominantly of hamster PrP-res and PrP-sen. Inhibitors were found among phthalocyanines, deuteroporphyrins IX, and meso-substituted porphines; examples included compounds containing anionic, neutral protic, and cationic peripheral substituents and various metals. We conclude that certain tetrapyrroles specifically inhibit the conversion of PrP-sen to PrP-res without apparent cytotoxic effects. The inhibition observed in the cell-free conversion reaction suggests that the mechanism involved direct interactions of the tetrapyrrole with PrP-res and/or PrP-sen. These findings introduce a new class of inhibitors of PrP-res formation that represents a potential source of therapeutic agents for transmissible spongiform encephalopathies. PMID:9770449

Complement inhibition prevents gut ischemia and endothelial cell dysfunction after hemorrhage/resuscitation.

PubMed

Fruchterman, T M; Spain, D A; Wilson, M A; Harris, P D; Garrison, R N

1998-10-01

Complement, a nonspecific immune response, is activated during hemorrhage/resuscitation (HEM/RES) and is involved in cellular damage. We hypothesized that activated complement injures endothelial cells (ETCs) and is responsible for intestinal microvascular hypoperfusion after HEM/RES. Four groups of rats were studied by in vivo videomicroscopy of the intestine: SHAM, HEM/RES, HEM/RES + sCR1 (complement inhibitor, 15 mg/kg intravenously given before resuscitation), and SHAM + sCR1. Hemorrhage was to 50% of mean arterial pressure for 60 minutes followed by resuscitation with shed blood plus an equal volume of saline. ETC function was assessed by response to acetylcholine. Resuscitation restored central hemodynamics to baseline after hemorrhage. After resuscitation, inflow A1 and premucosal A3 arterioles progressively constricted (-24% and -29% change from baseline, respectively), mucosal blood flow was reduced, and ETC function was impaired. Complement inhibition prevented postresuscitation vasoconstriction and gut ischemia. This protective effect appeared to involve preservation of ETC function in the A3 vessels (SHAM 76% of maximal dilation, HEM/RES 61%, HEM/RES + sCR1 74%, P < .05). Complement inhibition preserved ETC function after HEM/RES and maintained gut perfusion. Inhibition of complement activation before resuscitation may be a useful adjunct in patients experiencing major hemorrhage and might prevent the sequelae of gut ischemia.

Postactivation Potentiation Following Acute Bouts of Plyometric versus Heavy-Resistance Exercise in Collegiate Soccer Players.

PubMed

Sharma, Sourabh Kumar; Raza, Shahid; Moiz, Jamal Ali; Verma, Shalini; Naqvi, Irshad Husain; Anwer, Shahnawaz; Alghadir, Ahmad H

2018-01-01

Postactivation potentiation is referred to as an acute and temporary enhancement of muscle performance resulting from previous muscle contraction. The purpose of this study was to compare the acute effect of plyometric exercise (PLY) and heavy-resistance exercise (RES) on the blood lactate level (BLa) and physical performance. Fourteen male collegiate soccer players were randomized to perform either RES or PLY first and then crossed over to perform the opposite intervention. PLY consisted of 40 jumps, whereas RES comprised ten single repetitions at 90% of one repetition maximum. BLa and physical performance (countermovement jump height and 20-m sprint) were measured before and at 1 and 10 min following the exercise. No significant difference was observed in the BLa for both exercises (PLY and RES). Relative to baseline, countermovement jump (CMJ) height was significantly better for the PLY group after 1 min ( P = 0.004) and after 10 min ( P = 0.001) compared to that of the RES group. The 20-m sprint time was significantly better for PLY at 10 min ( P = 0.003) compared to that of RES. The present study concluded that, compared to RES, PLY causes greater potentiation, which leads to improved physical performance. This trial is registered with NCT03150277.

Collaborative decision-making on wind power projects based on AHP method

NASA Astrophysics Data System (ADS)

Badea, A.; Proştean, G.; Tămăşilă, M.; Vârtosu, A.

2017-01-01

The complexity of projects implementation in Renewable Energy Sources (RES) requires finding collaborative alliances between suppliers and project developers in RES. Links activities in supply chain in RES, respectively, transportation of heavy components, processing orders to purchase quality raw materials, storage and materials handling, packaging, and other complex activities requiring a logistics system collaboratively to be permanently dimensioned properly selected and monitored. Requirements imposed by stringency of wind power energy projects implementation inevitably involves constraints in infrastructure, implementation and logistics. Thus, following an extensive research in RES project, to eliminate these constraints were identified alternative collaboration to provide feasible solutions on different levels of performance. The paper presents a critical analysis of different collaboration alternatives in supply chain for RES projects, selecting the ones most suitable for particular situations by using decision-making method Analytic Hierarchy Process (AHP). The role of AHP method was to formulate a decision model by which can be establish the collaboration alternative choice through mathematical calculation to reduce the impact created by constraints encountered. The solution provided through AHP provides a framework for detecting optimal alternative collaboration between suppliers and project developers in RES and avoids some breaks in the chain by resizing safety buffers for leveling orders in RES projects.

A study of the turn-up effect in the electron momentum spectroscopy

NASA Astrophysics Data System (ADS)

Dal Cappello, C.; Menas, F.; Houamer, S.; Popov, Yu V.; Roy, A. C.

2015-10-01

Recently, a number of electron momentum spectroscopy measurements for the ionization of atoms and molecules have shown that the triple differential cross section (TDCS) has an unexpected higher intensity in a low momentum regime (Brunger M J, Braidwood S W, Mc Carthy I E and Weigold E 1994 J. Phys. B: At. Mol. Opt. Phys. 27 L597, Hollebone B P, Neville J J, Zheng Y, Brion C E, Wang Y and Davidson E R 1995 Chem. Phys. 196 13, Brion C E, Zheng Y, Rolke J, Neville J J, McCarthy I E and Wang J 1998 J. Phys. B: At. Mol. Opt. Phys. 31 L223, Ren X G, Ning C G, Deng J K, Zhang S F, Su G L, Huang F and Li G Q 2005 Phys. Rev. Lett. 94 163201, Deng J K, et al 2001 J. Chem. Phys. 114 882, Ning C G, Ren X G, Deng J K, Su G L, Zhang S F and Li G Q 2006 Phys. Rev. A 73 022704). This surprising result is now called the turn-up effect. Our aim is to investigate such an effect by studying the case of the ionization of atomic hydrogen in an excited state using the 3C model (Brauner M, Briggs J S and Klar H 1989 J. Phys. B: At. Mol. Opt. Phys. 22 2265) which is able to describe all the measured results of the single ionization of atomic hydrogen in its ground state for an incident energy beyond 200 eV. A comparison is also made of the findings of the present method with those of the plane wave impulse approximation and distorted wave models.

How can we help students appreciate physics education?

NASA Astrophysics Data System (ADS)

Lin, Jia-Ling; Zaki, Eman; Schmidt, Jason; Woolston, Don

2004-03-01

Helping students appreciate physics education is a formidable task, considering that many students struggle to pass introductory physics courses. Numerous efforts have been made for this undertaking because it is an important step leading to successful learning. In an out-of-classroom academic program, the Supplemental Instruction (SI) Program, we have used the approach, INSPIRE (inquiry, network, skillfulness, perseverance, intuition, reasoning, and effort), to help more students value their experiences in these courses. The method basically includes key elements outlined by experts in physics education [1]. Student responses have been encouraging. Having undergraduates as facilitators in the program is advantageous in promoting principles of physics education. Their training emphasizes tenacity, resourcefulness, understanding, support, and teamwork, i.e. TRUST. We present the organization and focus of the SI Program, and discuss how these improve learning atmosphere and facilitate learning. [1] Edward F. Redish et al, Am J. Phys. 66(3), March 1998.

Physics of the Cosmos Program Analysis Group (PhysPAG) Report

NASA Astrophysics Data System (ADS)

Nousek, John A.

2015-01-01

The Physics of the Cosmos Program Analysis Group (PhysPAG) serves as a forum for soliciting and coordinating input and analysis from the scientific community in support of the PCOS program objectives. I will outline the activities of the PhysPAG over the past year, since the last meeting during the AAS meeting in National Harbor, and mention the activities of the PhysPAG related Scientific Interest Groups.

Nonequilibrium Plasma Research

DTIC Science & Technology

2010-05-01

Kulikovsky, IEEE Trans. Plasma Sci. 25, 439 (1997). 61. W. Yi and P. Williams, J. Phys. D: Appl. Phys. 35, 205 (2002). 62. E. van Veldhuizen and W...Rutgers, J. Phys. D: Appl. Phys. 35, 2169 (2002). 63. E. van Veldhuizen , A. Baede, D. Hayashi, and W. Rutgers, APP Spring Meeting (Bad Honnef...Nonequilibrium Air Plasmas at Atmosphere Pressure, (Institute of Physics, Bristol, UK 2005) Review Article: P. Bletzinger, B. N. Ganguly, D. Van Wie and

Impurity and Defect Characterization in Epitaxial GaAs, InP and the Ternary and Quaternary Compound Semiconductors.

DTIC Science & Technology

1982-11-02

Wolfe, Phys. Rev. Lett. 27, 988 (1971). 5. H.R. Fetterman , D.M. Larsen, G.E. Stillman, P.E. Tannenwald, and J. Waldman, Phys.Rev. Lett. 26. 975(1971). 6...Kirkman, P.E. Simmonds, and R.A. Stradling, J. Phys. C., Solid State Phys. 8, 530 (1975). 18. H.R. Fetterman , J. Waldman and C.M. Wolfe, Solid State Commun

Methodological Choices in Muscle Synergy Analysis Impact Differentiation of Physiological Characteristics Following Stroke

PubMed Central

Banks, Caitlin L.; Pai, Mihir M.; McGuirk, Theresa E.; Fregly, Benjamin J.; Patten, Carolynn

2017-01-01

Muscle synergy analysis (MSA) is a mathematical technique that reduces the dimensionality of electromyographic (EMG) data. Used increasingly in biomechanics research, MSA requires methodological choices at each stage of the analysis. Differences in methodological steps affect the overall outcome, making it difficult to compare results across studies. We applied MSA to EMG data collected from individuals post-stroke identified as either responders (RES) or non-responders (nRES) on the basis of a critical post-treatment increase in walking speed. Importantly, no clinical or functional indicators identified differences between the cohort of RES and nRES at baseline. For this exploratory study, we selected the five highest RES and five lowest nRES available from a larger sample. Our goal was to assess how the methodological choices made before, during, and after MSA affect the ability to differentiate two groups with intrinsic physiologic differences based on MSA results. We investigated 30 variations in MSA methodology to determine which choices allowed differentiation of RES from nRES at baseline. Trial-to-trial variability in time-independent synergy vectors (SVs) and time-varying neural commands (NCs) were measured as a function of: (1) number of synergies computed; (2) EMG normalization method before MSA; (3) whether SVs were held constant across trials or allowed to vary during MSA; and (4) synergy analysis output normalization method after MSA. MSA methodology had a strong effect on our ability to differentiate RES from nRES at baseline. Across all 10 individuals and MSA variations, two synergies were needed to reach an average of 90% variance accounted for (VAF). Based on effect sizes, differences in SV and NC variability between groups were greatest using two synergies with SVs that varied from trial-to-trial. Differences in SV variability were clearest using unit magnitude per trial EMG normalization, while NC variability was less sensitive to EMG normalization method. No outcomes were greatly impacted by output normalization method. MSA variability for some, but not all, methods successfully differentiated intrinsic physiological differences inaccessible to traditional clinical or biomechanical assessments. Our results were sensitive to methodological choices, highlighting the need for disclosure of all aspects of MSA methodology in future studies. PMID:28912707

Methodological Choices in Muscle Synergy Analysis Impact Differentiation of Physiological Characteristics Following Stroke.

PubMed

Banks, Caitlin L; Pai, Mihir M; McGuirk, Theresa E; Fregly, Benjamin J; Patten, Carolynn

2017-01-01

Muscle synergy analysis (MSA) is a mathematical technique that reduces the dimensionality of electromyographic (EMG) data. Used increasingly in biomechanics research, MSA requires methodological choices at each stage of the analysis. Differences in methodological steps affect the overall outcome, making it difficult to compare results across studies. We applied MSA to EMG data collected from individuals post-stroke identified as either responders (RES) or non-responders (nRES) on the basis of a critical post-treatment increase in walking speed. Importantly, no clinical or functional indicators identified differences between the cohort of RES and nRES at baseline. For this exploratory study, we selected the five highest RES and five lowest nRES available from a larger sample. Our goal was to assess how the methodological choices made before, during, and after MSA affect the ability to differentiate two groups with intrinsic physiologic differences based on MSA results. We investigated 30 variations in MSA methodology to determine which choices allowed differentiation of RES from nRES at baseline. Trial-to-trial variability in time-independent synergy vectors (SVs) and time-varying neural commands (NCs) were measured as a function of: (1) number of synergies computed; (2) EMG normalization method before MSA; (3) whether SVs were held constant across trials or allowed to vary during MSA; and (4) synergy analysis output normalization method after MSA. MSA methodology had a strong effect on our ability to differentiate RES from nRES at baseline. Across all 10 individuals and MSA variations, two synergies were needed to reach an average of 90% variance accounted for (VAF). Based on effect sizes, differences in SV and NC variability between groups were greatest using two synergies with SVs that varied from trial-to-trial. Differences in SV variability were clearest using unit magnitude per trial EMG normalization, while NC variability was less sensitive to EMG normalization method. No outcomes were greatly impacted by output normalization method. MSA variability for some, but not all, methods successfully differentiated intrinsic physiological differences inaccessible to traditional clinical or biomechanical assessments. Our results were sensitive to methodological choices, highlighting the need for disclosure of all aspects of MSA methodology in future studies.

Summary of PhysPAG Activity

NASA Astrophysics Data System (ADS)

Nousek, John A.

2014-01-01

The Physics of the Cosmos Program Analysis Group (PhysPAG) is responsible for solicitiing and coordinating community input for the development and execution of NASA's Physics of the Cosmos (PCOS) program. In this session I will report on the activity of the PhysPAG, and solicit community involvement in the process of defining PCOS objectives, planning SMD architecture, and prioritizing PCOS activities. I will also report on the activities of the PhysPAG Executive Committee, which include the chairs of the Science Analysis Groups/ Science Interest Groups which fall under the PhysPAG sphere of interest. Time at the end of the presentation willl be reserved for questions and discussion from the community.

Cancer Treatment Side Effects: A Meta-analysis of the Relationship Between Response Expectancies and Experience.

PubMed

Devlin, Elise J; Denson, Linley A; Whitford, Hayley S

2017-08-01

Although previous research has, overall, suggested a moderate relationship between response expectancies (REs) and cancer treatment-related side effects, empirical results have been mixed. We aimed to further explore these relationships, hypothesizing that REs would predict subsequent toxicities with the inclusion of more recent studies, across a broader range of side effects, while incorporating the impact of potential moderators including patients' experience with treatment and measurement methods. We further investigated the impact of REs across individual toxicities. A systematic search and analysis were conducted across four databases (PsychInfo, PubMed, CINAHL, and Embase) and reference lists, from 1985 to February 2016. This provided 27 eligible studies with 4474 participants, through which the main analysis, moderator analyses, and individual side-effect analyses were explored. REs were moderately related to side effects overall (r = 0.26), and effect sizes were significantly influenced by sample diagnostic homogeneity, whereas differences between type and timing of measurement showed trends. Of the 16 toxicities examined, 15 demonstrated significant relationships between REs and side-effect experience, with hair loss (r = 0.48) the strongest. No clear difference emerged between objective and subjective side effects; however, significant differences across individual toxicities were revealed. Findings support a relationship between REs and a wide range of subsequent side effects, yet differences between individual RE-toxicity associations emerged. These findings provide direction for the measurement of side effects and REs and support REs as potential targets for intervention during the informed consent process. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Activation of mutated TRPA1 ion channel by resveratrol in human prostate cancer associated fibroblasts (CAF).

PubMed

Vancauwenberghe, Eric; Noyer, Lucile; Derouiche, Sandra; Lemonnier, Loïc; Gosset, Pierre; Sadofsky, Laura R; Mariot, Pascal; Warnier, Marine; Bokhobza, Alexandre; Slomianny, Christian; Mauroy, Brigitte; Bonnal, Jean-Louis; Dewailly, Etienne; Delcourt, Philippe; Allart, Laurent; Desruelles, Emilie; Prevarskaya, Natalia; Roudbaraki, Morad

2017-08-01

Previous studies showed the effects of resveratrol (RES) on several cancer cells, including prostate cancer (PCa) cell apoptosis without taking into consideration the impact of the tumor microenvironment (TME). The TME is composed of cancer cells, endothelial cells, blood cells, and cancer-associated fibroblasts (CAF), the main source of growth factors. The latter cells might modify in the TME the impact of RES on tumor cells via secreted factors. Recent data clearly show the impact of CAF on cancer cells apoptosis resistance via secreted factors. However, the effects of RES on PCa CAF have not been studied so far. We have investigated here for the first time the effects of RES on the physiology of PCa CAF in the context of TME. Using a prostate cancer CAF cell line and primary cultures of CAF from prostate cancers, we show that RES activates the N-terminal mutated Transient Receptor Potential Ankyrin 1 (TRPA1) channel leading to an increase in intracellular calcium concentration and the expression and secretion of growth factors (HGF and VEGF) without inducing apoptosis in these cells. Interestingly, in the present work, we also show that when the prostate cancer cells were co-cultured with CAF, the RES-induced cancer cell apoptosis was reduced by 40%, an apoptosis reduction canceled in the presence of the TRPA1 channel inhibitors. The present work highlights CAF TRPA1 ion channels as a target for RES and the importance of the channel in the epithelial-stromal crosstalk in the TME leading to resistance to the RES-induced apoptosis. © 2017 Wiley Periodicals, Inc.

Quantum-Critical Dynamics of the Skyrmion Lattice.

NASA Astrophysics Data System (ADS)

Green, Andrew G.

2002-03-01

Slightly away from exact filling of the lowest Landau level, the quantum Hall ferromagnet contains a finite density of magnetic vortices or Skyrmions[1,2]. These Skyrmions are expected to form a square lattice[3], the low energy excitations of which (translation/phonon modes and rotation/breathing modes) lead to dramatically enhanced nuclear relaxation[4,5]. Upon changing the filling fraction, the rotational modes undergo a quantum phase transition where zero-point fluctuations destroy the orientational order of the Skyrmions[4,6]. I will discuss the effect of this quantum critical point upon nuclear spin relaxation[7]. [1]S. L. Sondhi et al., Phys. Rev. B47, 16419 (1993). [2]S. E. Barrett et al., Phys. Rev. Lett. 74, 5112 (1995), A. Schmeller et al., Phys. Rev. Lett. 75, 4290 (1995). [3]L. Brey et al, Phys. Rev. Lett. 75, 2562 (1995). [4]R. Côté et al., Phys. Rev. Lett. 78, 4825 (1997). [5]R. Tycko et al., Science 268, 1460 (1995). [6]Yu V. Nazarov and A. V. Khaetskii, Phys. Rev. Lett. 80, 576 (1998). [7]A. G. Green, Phys. Rev. B61, R16 299 (2000).

Reynolds number effects on the single-mode Richtmyer-Meshkov instability

NASA Astrophysics Data System (ADS)

Walchli, B.; Thornber, B.

2017-01-01

The Reynolds number effects on the nonlinear growth rates of the Richtmyer-Meshkov instability are investigated using two-dimensional numerical simulations. A decrease in Reynolds number gives an increased time to reach nonlinear saturation, with Reynolds number effects only significant in the range Re<256 . Within this range there is a sharp change in instability properties. The bubble and spike amplitudes move towards equal size at lower Reynolds numbers and the bubble velocities decay faster than predicted by Sohn's model [S.-I. Sohn, Phys. Rev. E 80, 055302 (2009), 10.1103/PhysRevE.80.055302]. Predicted amplitudes show reasonable agreement with the existing theory of Carles and Popinet [P. Carles and S. Popinet, Phys. Fluids Lett. 13, 1833 (2001), 10.1063/1.1377863; Eur. J. Mech. B 21, 511 (2002), 10.1016/S0997-7546(02)01199-8] and Mikaelian [K. O. Mikaelian, Phys. Rev. E 47, 375 (1993), 10.1103/PhysRevE.47.375; K. O. Mikaelian, Phys. Rev. E 87, 031003 (2013), 10.1103/PhysRevE.87.031003], with the former being the closest match to the current computations.

NREL: International Activities - Pakistan Resource Maps

Science.gov Websites

. The high-resolution (1-km) annual wind power maps were developed using a numerical modeling approach along with NREL's empirical validation methodology. The high-resolution (10-km) annual and seasonal KB) | High-Res (ZIP 281 KB) 40-km Resolution Annual Maps (Direct) Low-Res (JPG 156 KB) | High-Res

ResStock - Targeting Energy and Cost Savings for U.S. Homes | NREL

Science.gov Websites

ResStock - Targeting Energy and Cost Savings for U.S. Homes Science and Technology Highlights Highlights in Research & Development ResStock - Targeting Energy and Cost Savings for U.S. Homes Key discovered $49 billion in potential annual utility bill savings through cost-effective energy efficiency

University of Utrecht 1636-1676: "Res Ecclesia, Res Publica and … Res Pecunia"

ERIC Educational Resources Information Center

van Rinsum, Henk; Koops, Willem

2016-01-01

The early history of Utrecht University (founded 1636) reflects an emerging public sphere (Habermas's "bürgerliche öffentlichkeit") of a major town in the Netherlands. This public sphere was a contested field among the different groups establishing and administering the university: university professors, town magistrates and…

Neuroprotective effect of resveratrol against brain ischemia reperfusion injury in rats entails reduction of DJ-1 protein expression and activation of PI3K/Akt/GSK3b survival pathway.

PubMed

Abdel-Aleem, Ghada A; Khaleel, Eman F; Mostafa, Dalia G; Elberier, Lydia K

2016-10-01

In the current study, we aimed to investigate the mechanistic role of DJ-1/PI3K/Akt survival pathway in ischemia/reperfusion (I/R) induced cerebral damage and to investigate if the resveratrol (RES) mediates its ischemic neuroptotection through this pathway. RES administration to Sham rats boosted glutathione level and superoxide dismutase activity and downregulated inducible nitric oxide synthase expression without affecting redox levels of DJ-1 forms or components of PI3K/Akt pathway including PTEN, p-Akt or p/p-GSK3b. However, RES pre-administration to I/R rats reduced infarction area, oxidative stress, inflammation and apoptosis. Concomitantly, RES ameliorated the decreased levels of oxidized forms of DJ-1 and enhancing its reduction, increased the nuclear protein expression of Nfr-2 and led to activation of PI3K/Akt survival pathway. In conclusion, overoxidation of DJ-1 is a major factor that contributes to post-I/R cerebral damage and its reduction by RES could explain the neuroprotection offered by RES.

Influence of signal processing strategy in auditory abilities.

PubMed

Melo, Tatiana Mendes de; Bevilacqua, Maria Cecília; Costa, Orozimbo Alves; Moret, Adriane Lima Mortari

2013-01-01

The signal processing strategy is a parameter that may influence the auditory performance of cochlear implant and is important to optimize this parameter to provide better speech perception, especially in difficult listening situations. To evaluate the individual's auditory performance using two different signal processing strategy. Prospective study with 11 prelingually deafened children with open-set speech recognition. A within-subjects design was used to compare performance with standard HiRes and HiRes 120 in three different moments. During test sessions, subject's performance was evaluated by warble-tone sound-field thresholds, speech perception evaluation, in quiet and in noise. In the silence, children S1, S4, S5, S7 showed better performance with the HiRes 120 strategy and children S2, S9, S11 showed better performance with the HiRes strategy. In the noise was also observed that some children performed better using the HiRes 120 strategy and other with HiRes. Not all children presented the same pattern of response to the different strategies used in this study, which reinforces the need to look at optimizing cochlear implant clinical programming.

Nanoparticle-macrophage interactions: A balance between clearance and cell-specific targeting

PubMed Central

Rattan, Rahul; Bhattacharjee, Somnath; Zong, Hong; Swain, Corban; Siddiqui, Muneeb A.; Visovatti, Scott H.; Kanthi, Yogendra; Desai, Sajani; Pinsky, David J.; Goonewardena, Sascha N.

2017-01-01

The surface properties of nanoparticles (NPs) are a major factor that influences how these nanomaterials interact with biological systems. Interactions between NPs and macrophages of the reticuloendothelial system (RES) can reduce the efficacy of NP diagnostics and therapeutics. Traditionally, to limit NP clearance by the RES system, the NP surface is neutralized with molecules like poly(ethylene glycol) (PEG) which are known to resist protein adsorption and RES clearance. Unfortunately, PEG modification is not without drawbacks including difficulties with the synthesis and associations with immune reactions. To overcome some of these obstacles, we neutralized the NP surface by acetylation and compared this modification to PEGylation for RES clearance and tumor-specific targeting. We found that acetylation was comparable to PEGylation in reducing RES clearance. Additionally, we found that dendrimer acetylation did not impact folic acid (FA)-mediated targeting of tumor cells whereas PEG surface modification reduced the targeting ability of the NP. These results clarify the impact of different NP surface modifications on RES clearance and cell-specific targeting and provide insights into the design of more effective NPs. PMID:28705434

US defensive operations against Libya and the nuclear accident at Chernobyl. Markup before the Committee on Foreign Affairs, House of Representatives, Ninety-Ninth Congress, Second Session on H. Res. 424 and H. Res 440, May 1, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-01-01

The House Foreign Affairs Committee met to mark up two resolutions: H. Res. 424 and H. Res. 440. H. Res. 424 thanks the United Kingdom for its assistance in the April 14, 1986 operation against Libya. Despite objections to the raid and to including the British, as well as questions about the quality of the US response and about the President's compliance with the Constitution and the War Powers Resolution, the resolution passed. H. Res. 440 expresses sympathy to the victims of the Chernobyl accident and asks the Soviet Union to relax restrictions on communications and the transfer of whatevermore » technology and assistance will be helpful. It also criticizes the Soviet handling of information about the accident. An amendment strengthened the wording of the criticism, and the resolution passed. The report includes the committee discussion and the tests of the two resolutions.« less

Reply to "Comment on `Particle path through a nested Mach-Zehnder interferometer' "

NASA Astrophysics Data System (ADS)

Griffiths, Robert B.

2018-02-01

While much of the technical analysis in the preceding Comment is correct, in the end it confirms the conclusion reached in my previous work [Phys. Rev. A 94, 032115 (2016), 10.1103/PhysRevA.94.032115]: A consistent histories analysis provides no support for the claim of counterfactual quantum communication put forward by Salih et al. [Phys. Rev. Lett. 110, 170502 (2013), 10.1103/PhysRevLett.110.170502].

α-decay systematics for superheavy elements

NASA Astrophysics Data System (ADS)

Duarte, S. B.; Teruya, N.

2012-01-01

In this Brief Report we extend the α-decay half-life calculation to the superheavy emitter region to verify whether these nuclei satisfy the recently observed systematics [D. N. Poenaru , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.83.014601 83, 014601 (2011);C. Qi , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.80.044326 80, 044326 (2009)]. To establish the systematics, we have used the α-cluster potential description, which was originally developed to study α decay in connection with nuclear energy level structure [B. Buck , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.51.559 51, 559 (1995)]. The quantum-mechanical tunneling calculation has been employed to obtain the half-lives, showing that with this treatment the systematics are well reproduced in the region of heavy nuclei. Finally, the half-life calculation has been extended to the superheavy emitters to verify whether the systematics can still be observed.

One-loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus

NASA Astrophysics Data System (ADS)

Bondarenko, S.; Lipatov, L.; Pozdnyakov, S.; Prygarin, A.

2017-09-01

The effective action for reggeized gluons is based on the gluodynamic Yang-Mills Lagrangian with external current for longitudinal gluons added, see Lipatov (Nucl Phys B 452:369, 1995; Phys Rep 286:131, 1997; Subnucl Ser 49:131, 2013; Int J Mod Phys Conf Ser 39:1560082, 2015; Int J Mod Phys A 31(28/29):1645011, 2016; EPJ Web Conf 125:01010, 2016). On the base of classical solutions, obtained in Bondarenko et al. (Eur Phys J C 77(8):527, 2017), the one-loop corrections to this effective action in light-cone gauge are calculated. The RFT calculus for reggeized gluons similarly to the RFT introduced in Gribov (Sov Phys JETP 26:414, 1968) is proposed and discussed. The correctness of the results is verified by calculation of the propagators of A+ and A- reggeized gluons fields and application of the obtained results is discussed as well.

Effects of ranavirus infection of red-eared sliders (Trachemys scripta elegans) on plasma proteins.

PubMed

Moore, A Russell; Allender, Matthew C; MacNeill, Amy L

2014-06-01

Ranavirus is an emerging disease that infects fish, amphibians, and reptiles. Ranavirus induces an inflammatory response leading to death in many susceptible species. Red-eared sliders (RES; Trachemys scripta elegans) are vulnerable to ranavirus infection and are economically significant chelonians kept in the pet trade and utilized in research. Early identification of RES with inflammatory diseases would allow for isolation of affected individuals and subsequent disease investigation, including molecular testing for ranavirus. Validation of an inexpensive, clinically relevant, and reproducible diagnostic test that detects inflammation in turtles is needed. Although commonly used, plasma protein electrophoresis to detect an inflammatory acute-phase protein response has not been evaluated in a controlled environment in turtles with experimentally induced inflammatory disease. The objective of this study was to measure plasma protein fractions by electrophoresis to determine if an acute-phase protein response occurs in RES during infection with a frog virus 3-like ranavirus (FV3-like virus) isolated from a chelonian. A Bradford assay and agarose gel electrophoresis (AGE) were performed using plasma collected during a study of the effect of temperature on the pathogenesis of ranavirus in RES. In RES at the time of viremia, total albumin (ALB(mg/ml)) and albumin to globulin ratio were significantly lower and beta-globulin percentage was significantly higher in RES exposed to ranavirus (n = 4) as compared to matched, uninfected RES (n = 8). In the last sample collected prior to death, total protein (TP(mg/ml)), ALB(mg/ml), alpha-globulin percentage, and total alpha-globulin (alpha(mg/ml)) were significantly lower in RES exposed to ranavirus (n = 4) than control individuals (n = 8). In summary, FV3-like virus induces a decrease in plasma albumin concentration at the onset ofviremia and decreases in TP(mg/ml, ALB(mg/ml), and alpha(mg/ml) concentrations prior to death in RES as measured by AGE.

Hepatic transcriptome analysis of juvenile GIFT tilapia (Oreochromis niloticus), fed diets supplemented with different concentrations of resveratrol.

PubMed

Zheng, Yao; Wu, Wei; Hu, Gengdong; Zhao, Zhixiang; Meng, Shunlong; Fan, Limin; Song, Chao; Qiu, Liping; Chen, Jiazhang

2018-01-01

The GIFT (Genetically Improved Farmed Tilapia) tilapia, Oreochromis niloticus, is cultured widely for the production of freshwater fish in China. Streptococcosis, which is related to pathogenic infections, occurs frequently in juvenile and adult female GIFT individuals. Resveratrol (RES) has been used in feed to control these infections in freshwater tilapia. To address the effects of RES on tilapia, we used high-throughput RNA sequencing technology (RNA-Seq, HiSeq. 2500) to explore the global transcriptomic response and specific involvement of hepatic mRNA of juvenile O. niloticus fed with diets containing different concentrations of (0, 0.025, 0.05, and 0.1g/kg) RES. A total of > 24,513,018 clean reads were generated and then assembled into 23,244 unigenes. The unigenes were annotated by comparing them against non-redundant protein sequence (Nr), non-redundant nucleotide (Nt), Swiss-Prot, Pfam, Gene Ontology database (GO), Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and 12,578 unigenes were annotated to the GO database. A total of 1444 (0.025g/kg RES), 1526 (0.05g/kg RES), and 3135 (0.1g/kg RES) genes were detected as significant differentially expressed genes (DEGs), when compared with the controls. A total of 6 (0.025 vs 0.05g/kg RES), 19 (0.025 vs 0.1g/kg RES), and 124 (0.05 vs 0.1g/kg RES) genes were detected as significant DEGs. Six genes, including dnah7x1, sox4, fam46a, hsp90a, ddit4, and nmrk2, were associated with an immune response. These findings provide information on the innate immunity of GIFT and might contribute to the development of strategies for the effective management of diseases and long-term sustainability of O. niloticus culture. Copyright © 2017 Elsevier Inc. All rights reserved.

Alleviation of Acute Lung Injury in Rats with Sepsis by Resveratrol via the Phosphatidylinositol 3-Kinase/Nuclear Factor-Erythroid 2 Related Factor 2/Heme Oxygenase-1 (PI3K/Nrf2/HO-1) Pathway.

PubMed

Wang, Yu; Wang, Xiaofeng; Zhang, Lichun; Zhang, Rong

2018-05-30

BACKGROUND Resveratrol (Res) is a type of polyphenol found in many plants, which can protect important organs from the damage induced by sepsis. However, the exact mechanism of its protective effect has not been established. This study investigated the effect of Res on the PI3K/Nrf2/HO-1 signaling pathway in rats with sepsis-induced acute lung injury (ALI). MATERIAL AND METHODS Male Wistar rats were treated with 30 mg/kg Res by intraperitoneal administration for 1 hour immediately after cecal ligation and puncture. Levels of MIP-2, IL-18, and IL-10 in bronchoalveolar lavage fluid (BALF) were determined. Lung tissues were collected to measure the wet-to-dry (W/D) ratios, oxidative stress index, and lung injury scores. Expression levels of Akt, p-Akt, HO-1, Nrf-2, and active caspase-3 proteins were determined by western blotting; expression of HO-1 mRNA was determined by RT-PCR. RESULTS Treatment with Res significantly decreased the levels of MIP-2 and IL-18 and increased IL-10 in the BALF of rats with sepsis-induced ALI. In addition, Res also effectively reduced the W/D lung weight ratio, lung injury score, and the levels of MDA (malondialdehyde) and 8-OHdG. Conversely, Res increased SOD (superoxide dismutase) activity in the lung tissue. Moreover, Res significantly induced higher HO-1 mRNA expression, upregulated HO-1 and Nrf-2 protein expression, and the phosphorylation of Akt in the lung tissue. In contrast, the levels of activated caspase-3 protein were decreased in Res-treated rats (P<0.05). CONCLUSIONS Res could inhibit inflammation, oxidative stress, and cell apoptosis to alleviate ALI in septic rats through the inhibition of the PI3K/Nrf2/HO-1 signaling pathway.

Aqueous aerosol may build up large upper tropospheric ice supersaturation

NASA Astrophysics Data System (ADS)

Bogdan, Anatoli; Molina, Mario J.

2010-05-01

Keywords: ice supersaturation, upper tropospheric cirrus clouds, freezing of aqueous aerosol. Observations often reveal enhanced and persistent upper tropospheric (UT) ice supersaturation, Si up to 100%, independently of whether cirrus ice clouds are present or not (Krämer et al., 2009; Lawson et al., 2008). However, a water activity criterion (WAC) (Koop et al., 2000) does not allow the formation of Si > ~67% by the homogeneous freezing of aqueous droplets even at the lowest atmospheric temperature of ~185 K. For aqueous aerosol the WAC predicts the existence of a so called homogeneous ice nucleation threshold which, being expressed as Si, is between ~52 and 67% in the temperature range of ~220 - 185 K. The nature of the formation of large Si remains unclear. Since water vapor is the dominant greenhouse gas it is important to know the nature of the accumulation and persistence of water vapor in the UT. We studied the freezing behavior of micrometer-scaled 3-, 4-, and 5-component droplets, which contain different weight fractions of H2O, H2SO4, HNO3, (NH4)2SO4, (NH4)HSO4, NH4NO3, and (NH4)3H(SO4)2. The study was performed between 133 and 278 K at cooling rates of 3, 0.1, and 0.05 K/min using differential scanning calorimetry (DSC) (Bogdan and Molina, 2010). The cooling rates of 0.1 and 0.05 K/min (6 and 3 K/h) are similar to the smallest reported synoptic temperature change of ~2 K/h (Carslaw et al., 1998). Using the measured freezing temperature of ice, Ti, and the thermodynamic E-AIM model of the system of H+ - NH4+ - SO42-- NO3-- H2O (Clegg et al., 1998), we calculated the corresponding clear-sky Si which would be built up immediately prior to the formation of ice cirrus clouds by the homogeneous freezing of aqueous aerosol of similar composition. We found that our calculated values of Si are both larger and smaller than the homogeneous ice nucleation threshold. For example, for the droplets of compositions of 15/10 and 20/10 wt % (NH4)3H(SO4)2/H2SO4, which freeze at 194 and 186 K, respectively, the calculated clear-sky Si can exceed 80%. Although our Si values are smaller than the largest observed value of Si ≈ 100%, they are nevertheless larger than the Si ≈ 67% predicted by the WAC at 185 K. Our results can give an impetus for the study of whether multi-component aqueous aerosol, which besides inorganic components also contains organics, may produce the observed Si ≈ 100%. Krämer, M., Schiller, C., Afchine, A., Bauer, R., Gensch, I., Mangold, A.., Schlicht, S., Spelten, N., Sitnikov, N., Borrmann, S., de Reus, M., Spichtinger, P. (2009), Atmos. Chem. Phys. 9, 3505. Lawson, R. P., Pilson, B., Baker, B., Mo, Q., Jensen, E., Pfister, L., Bui, P. (2008), Atmos. Chem. Phys. 8, 1609. Koop, T., Luo, B., Tsias, A., Peter, T. (2000), Nature, 406, 611. Bogdan, A. and Moilna, M. J. (2010), J. Phys. Chem. A (Published online: 5 February). Carslaw, K. S., Wirth, M., Tsias, A., Luo, B. P., Dörnbrack, A., Leutbecher, M., Volkert, H., Renger, W., Bacmeister, J. T., Peter, T. (1998), J. Geophys. Res. 103, 5785. Clegg, S. L., Brimblecombe, P., Wexler, A. S. (1998), J. Phys. Chem. A 102, 2137.

Sources of Water-soluble Organic Aerosol in the Southeastern United States - Evidence of SOA Formed Through Heterogeneous Reactions

NASA Astrophysics Data System (ADS)

Zhang, X.; Weber, R. J.

2010-12-01

Recent laboratory studies suggest partitioning of semi-volatile organic compounds (SVOCs) to liquid water followed by heterogeneous chemical transformation as a possible route to forming secondary organic aerosol (SOA). This paper will present results from observational studies of SOA formation using Water-Soluble Organic Carbon (WSOC) fraction of SOA, soluble brown carbon (e.g., light absorption spectra), organic acids and a number of aerosol source tracers in the Southeastern U.S., a region known for extensive biogenic and anthropogenic VOC emissions. Based on 24-h integrated filter measurements at 15 sites in the southeast throughout the year of 2007, a PMF analysis identified a factor characterized by the co-abundance of WSOC (58 percent of the total), oxalate (51 percent) and brown carbon (Abs365) (44 percent), which is consistent with the aqueous phase SOA formation mechanism in which water-soluble organic products from gas-phase photochemistry dissolve in liquid (fog/cloud droplets or particle water) and react further to form oligomers, light absorbing compounds, and light-weight organic acids, with oxalic acid being the most abundant one [Hecobian et al., 2010; Zhang et al., 2010]. The temporal variability of this factor correlated well with ambient temperature, possibly owing to the large impact from biogenic emissions, which are dependent on temperature and known to be significant over the southeast. PMF analysis of other data sets collected in Atlanta with online instruments during summer support these findings; as do other studies based on different data sets and data-analysis methods [Hennigan et al., 2008a; Hennigan et al., 2008b; Hennigan et al., 2008c; Hennigan et al., 2009]. Overall, we find that WSOC is largely secondary (roughly 75 to 85 percent) and estimate that 65 to 75 percent of the secondary WSOC formed in the southeast involves some form of aqueous phase chemical process. Hecobian, A., X. Zhang, M. Zheng, N. Frank, E. S. Edgerton, and R. J. Weber (2010), Water-soluble organic aerosol material and the light-absorption characteristics of aqueous extracts measured over the southeastern United States, Atm. Chem. Phys., 10, 5965-5977. Hennigan, C. J., M. H. Bergin, J. E. Dibb, and R. J. Weber (2008a), Enhanced secondary organic aerosol formation due to water uptake by fine particles, Geophys. Res. Lett., 35, L18801, 18810.11029/12008GL035046. Hennigan, C. J., M. H. Bergin, and R. J. Weber (2008b), Correlations between water-soluble organic aerosol and water vapor: A synergistic effect from biogenic emissions?, Environ. Sci. Tech., 42(24), 9079-9085. Hennigan, C. J., et al. (2008c), On the volatility and production mechanisms of newly formed nitrate and water soluble organic aerosol in Mexico City, Atm. Chem. Phys., 8, 3761-3768. Hennigan, C. J., M. H. Bergin, A. G. Russell, A. Nenes, and R. J. Weber (2009), Gas/particle partitioning of water-soluble organic aerosol in Atlanta, Atm. Chem. Phys., 9, 3613-3628. Zhang, X., A. Hecobian, M. Zheng, N. Frank, and R. J. Weber (2010), Biomass buring impact on PM2.5 over the southeastern U.S.: Intgrating chemically speciated FRM filter measurements, MODIS fire counts and PMF analysis, Atm. Chem. Phys., 10, 6839-6853.

The time-dependence of the defective nature of ice Ic (cubic ice) and its implications for atmospheric science

NASA Astrophysics Data System (ADS)

Sippel, Christian; Koza, Michael M.; Hansen, Thomas C.; Kuhs, Werner F.

2010-05-01

The possible atmospheric implication of ice Ic (cubic ice) has already been suggested some time ago in the context of snow crystal formation [1]. New findings from air-borne measurements in cirrus clouds and contrails have put ice Ic into the focus of interest to understand the so-called "supersaturation puzzle" [2,3,4]. Our recent microstructural work on ice Ic [5,6] appears to be highly relevant in this context. We have found that ice Ic is characterized by a complex stacking fault pattern, which changes as a function of temperature as well as time. Indeed, from our own [7] and other group's work [8] one knows that (in contrast to earlier believe) ice Ic can form up to temperatures at least as high as 240K - thus in the relevant range for cirrus clouds. We have good preliminary evidence that the "cubicity" (which can be related to stacking fault probabilities) as well as the particle size of ice Ic are the relevant parameters for this correlation. The "cubicity" of stacking faulty ice Ic (established by diffraction) correlates nicely with the increased supersaturation at decreasing temperatures observed in cirrus clouds and contrails, a fact, which may be considered as further evidence for the presence of ice Ic. Recently, we have studied the time-dependency of the changes in both "cubicity" and particle size at various temperatures of relevance for cirrus clouds and contrails by in-situ neutron powder diffraction. The timescales over which changes occur (several to many hours) are similar to the life-time of cirrus clouds and contrails and suggest that the supersaturation situation may change within this time span in the natural environment too. Some accompanying results obtained by cryo-SEM (scanning electron microscopy) work will also be presented and suggest that stacking-faulty ice Ic has kinky surfaces providing many more active centres for heterogeneous reactions on the surface than in the usually assumed stable hexagonal form of ice Ih with its rather flat low-indexed crystal faces. [1] T Kobayashi & T Kuroda (1987) Snow Crystals. In: Morphology of Crystals (ed. I Sunagawa), Terra Scientific Publishing, Tokyo, pp.649-743. [2] RS Gao & 19 other authors (2004) Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds. Science 303, 516-520. [3] T Peter, C Marcolli, P Spichtinger, T Corti, MC Baker & T Koop (2006) When dry air is too humid. Science 314, 1399-1402. [4] JE Shilling, MA Tolbert, OB Toon, EJ Jensen, BJ Murray & AK Bertram (2006) Measurements of the vapor pressure of cubic ice and their implications for atmospheric ice clouds. Geophys.Res.Lett. 33, 026671. [5] TC Hansen, MM Koza & WF Kuhs (2008) Formation and annealing of cubic ice: I Modelling of stacking faults. J.Phys.Cond.Matt. 20, 285104. [6] TC Hansen, MM Koza, P Lindner & WF Kuhs (2008) Formation and annealing of cubic ice: II. Kinetic study. J.Phys.Cond.Matt. 20, 285105. [7] WF Kuhs, G Genov, DK Staykova & AN Salamatin, T Hansen (2004) Ice perfection and the onset of anomalous preservation of gas hydrates. Phys.Chem.Chem.Phys. 6, 4917-4920. [8] BJ Murray, DA Knopf & AK Bertram (2005) The formation of cubic ice under conditions relevant to Earth's atmosphere. Nature 434, 292-205.

Shock-wave ion acceleration by an ultra-relativistic short laser pulse

NASA Astrophysics Data System (ADS)

Zhidkov, A.; Batishchev, O.; Uesaka, M.

2002-11-01

Research on ion acceleration by intense short laser pulses grows in the last few years [1-9] because of various applications. However, the study is mainly focused on the forward ion acceleration. We study ion inward acceleration, which in contrast to other mechanisms has density of ions per unit energy not decreased with the laser intensity [8]. Magnetic field generated due to a finite size of laser spot can affect electron distribution. In the present work we study the effect of magnetic field on the shock wave formation and ion acceleration in a solid target via 2D PIC and Vlasov simulation. Though the PIC simulation can provide detailed information, in relativistic plasmas it may not calculate B correctly: (i) too many particles are needed to make B disappeared in thermal plasmas, (ii) local scheme [10] does not satisfy curl(Epl)=0. Therefore, two approaches are used in the present study. [1] S. P. Hatchett et al., Phys. Plas. 7, 2076 (2000); [2] A. Maksimchuk et al., Phys. Rev. Lett. 84, 4108 (2000); [3] E.L. Clark et al., Phys. Rev. Lett. 85, 1654 (2000); [4] A. Zhidkov et al., Phys. Rev. E60, 3273 (1999); E61, R2224 (2000); [5] Y. Murakami et al, Phys. Plasmas 8,4138 (2001); [6] T.Zh. Esirkepov et al, JETP Lett. 70, 82 (1999); [7] A. Pukhov, Phys. Rev. Lett. 86, 3562(2001); [8] A.A. Andreev et al., Plasma Phys. Contr. Fusion (2002); [9] O.V. Batishchev et al., Plasma Phys. Rep. 20, 587 (1994); [10] J. Villasenor et al., Comp. Phys. Comm. 69, 306 (1992).

Loading Intensity Prediction by Velocity and the OMNI-RES 0-10 Scale in Bench Press.

PubMed

Naclerio, Fernando; Larumbe-Zabala, Eneko

2017-02-01

Naclerio, F and Larumbe-Zabala, E. Loading intensity prediction by velocity and the OMNI-RES 0-10 scale in bench press. J Strength Cond Res 32(1): 323-329, 2017-This study examined the possibility of using movement velocity and the perceived exertion as indicators of relative load in the bench press (BP) exercise. A total of 308 young, healthy, resistance trained athletes (242 men and 66 women) performed a progressive strength test up to the one repetition maximum for the individual determination of the full load-velocity and load-exertion relationships. Longitudinal regression models were used to predict the relative load from the average velocity (AV) and the OMNI-Resistance Exercise Scales (OMNI-RES 0-10 scale), considering sets as the time-related variable. Load associated with the AV and the OMNI-RES 0-10 scale value expressed after performing a set of 1-3 repetitions were used to construct 2 adjusted predictive equations: Relative load = 107.75 - 62.97 × average velocity; and Relative load = 29.03 + 7.26 × OMNI-RES 0-10 scale value. The 2 models were capable of estimating the relative load with an accuracy of 84 and 93%, respectively. These findings confirm the ability of the 2 calculated regression models, using load-velocity and load-exertion from the OMNI-RES 0-10 scale, to accurately predict strength performance in BP.

What influences climate and glacier change in southwestern China?

NASA Astrophysics Data System (ADS)

Yasunari, Teppei J.

2011-12-01

The subject of climate change in the Tibetan Plateau (TP) and Himalayas has taken on increasing importance because of the availability of water resources from their mountain glaciers (Immerzeel et al 2010). Many of the glaciers over these regions have been retreating, while some are advancing and stable (Yao et al 2004, Scherler et al 2011). Other studies report that some glaciers in the Himalayas show acceleration of their shrinkage (e.g., Fujita and Nuimura 2011). However, the causes of glacier melting are still difficult to grasp because of the complexity of climatic change and its influence on glacier issues. Despite this, it is vital that we pursue further study to enable future predictions of glacier changes. The paper entitled 'Climate and glacier change in southwestern China during the past several decades' by Li et al (2011) provided carefully analyzed, quality controlled, long-term data on atmospheric temperature and precipitation during the period 1961-2008. The data were obtained from 111 Chinese stations. The researchers performed systematic analyses of temperature and precipitation over the whole southwestern Chinese domain. They discussed those changes in terms of other meteorological components such as atmospheric circulation patterns, radiation and altitude difference, and then showed how these factors could contribute to climate and glacier changes in the region. Air temperature and precipitation are strongly associated with glacier mass balance because of heat balance and the addition of mass when it snows. Temperature warming trends over many places in southwestern China were unequivocally dominant in all seasons and at higher altitudes. This indicates that the heat contribution to the glaciers has been increasing. On the other hand, precipitation has a wider variability in time and space. It is more difficult to clearly understand the effect of precipitation on the climate and glacier melting characteristics in the whole of southwestern China as a collective view. However, the precipitation patterns in southwestern China are probably modulated by climate feedbacks through many factors. Precipitation seasonality may also affect the climatic sensitivity of glacier mass balance (Fujita 2008). In addition to the authors' main focus above, other factors, also probably directly and indirectly, influence the climate and glacier mass balance changes. Those factors are: (a) The debris-covered effect which heats (if it is thin) or insulates (if it is thick) the ice below the debris; it probably causes no uniform response on glacier melting (Scherler et al 2011); (b) Interaction between glacial lakes and exposed ice parts on glaciers (e.g., Sakai et al 2009, Fujita et al 2009); (c) The atmospheric heating effect over the foothills of the Himalayas due to the Atmospheric Brown Cloud (ABC), including absorbing aerosols such as black carbon, dust and organic matters (Ramanathan et al 2007), the so called Elevated Heat Pump (EHP) effect suggested by Lau et al (2006, 2010); (d) The snow darkening effect over non debris-covered parts of glaciers as the absorbing aerosol depositions reduce snow albedo and accelerate snow melting by absorbing more solar energy at the snow surface (Warren and Wiscombe 1980, Flanner et al 2007, 2009, Yasunari et al 2010, Qian et al 2011); (e) Another kind of snow darkening effect over non debris-covered glaciers due to the growth of biological activities, with dark-colored materials on glaciers also reducing snow albedo (Takeuchi et al 2001); (f) Other factors on snow albedo reductions such as snow grain size, specific surface area and depth changes, melt-water effect on snow, and changes in solar illumination conditions (e.g., Wiscombe and Warren 1980, Flanner et al 2006, Yasunari et al 2011, Aoki et al 1999, 2011); and finally, (g) Feedbacks via interactions between the snow surface and atmosphere including all the factors above. What I'd like to emphasize is that the atmospheric warming trend indicated by Li et al (2011) is robust and very likely associated with the dominant characteristics of glacier shrinkage across southwestern China, as discussed by the authors. However, the shrinkage rate of sub-regional scale variability is probably due to the modulation of precipitation, as well as the other factors identified above. Further, atmospheric warming is not limited only to southwestern China, but is also probable in the surrounding Tibetan and Himalayan regions (Gautam et al 2010). Comprehensive studies, including international projects discussing all the contributors above by (a) field observations, (b) global or regional modeling, and (c) satellite data analyses, are essential to assess the future climate change and glacier retreat in/around the TP and Himalayas. The authors' findings showed robust information on atmospheric warming trends and some wider variety on precipitation during 1961-2008 in southwestern China. In addition, they indicated some possible connections between these findings and atmospheric circulation, altitudinal difference and meteorological conditions. Future studies should promote a deeper discussion and understanding of these relationships. Hereafter, we must make a committed effort to study climate and glacier issues in/around the TP and Himalayas involving the existing warming trend. This trend fluctuates year-by-year. The fluctuation of the warming and precipitation changes may directly contribute to climate change and glacier retreats. However, the seven factors noted above likely modulate the climate change and glacier melting patterns in southwestern China on the warming trend in intra- and inter-annual timescales. The temperature and precipitation data in this study offer a terrific asset for future studies on climate and glacier issues in/around this region. Acknowledgement I wish to thank Jan Angevine at NASA/GSFC for proofreading. References Aoki Te, Aoki Ta, Fukabori M and Uchiyama A 1999 Numerical simulation of the atmospheric effects on snow albedo with a multiple scattering radiative transfer model for the atmosphere-snow system J. Meteorol. Soc. Japan 77 595-614 Aoki Te, Kuchiki K, Niwano M, Kodama Y, Hosaka M and Tanaka T 2011 Physically based snow albedo model for calculating broadband albedos and the solar heating profile in snowpack for general circulation models J. Geophys. Res. 116 D11114 Flanner M G and Zender C S 2006 Linking snowpack microphysics and albedo evolution J. Geophys. Res. 111 D12208 Flanner M G, Zender C S, Randerson J T and Rasch P J 2007 Present-day climate forcing and response from black carbon in snow J. Geophys. Res. 112 D11202 Flanner M G, Zender C S, Hess P G, Mahowald N M, Painter T H, Ramanathan V and Rasch P J 2009 Springtime warming and reduced snow cover from carbonaceous particles Atmos. Chem. Phys. 9 2481-97 Fujita K 2008 Effect of precipitation seasonality on climatic sensitivity of glacier mass balance Earth Planet. Sci. Lett. 276 14-9 Fujita K, Sakai A, Nuimura T, Yamaguchi S and Sharma R 2009 Recent changes in Imja Glacial Lake and its damming moraine in the Nepal Himalaya revealed by in situ surveys and multi-temporal ASTER imagery Environ. Res. Lett. 4 045205 Fujita K and Nuimura T 2011 Spatially heterogeneous wastage of Himalayan glaciers Proc. Natl Acad. Sci. USA at press doi: 10.1073/pnas.1106242108 Gautam R, Hsu N C and Lau K M 2010 Premonsoon aerosol characterization and radiative effects over the Indo-Gangetic Plains: Implications for regional climate warming J. Geophys. Res. 115 D17208 Immerzeel W W, van Beek L P H and Bjerkens M F P 2010 Climate change will affect the Asian water towers Science 328 1382-5 Lau K M, Kim M K and Kim K M 2006 Asian monsoon anomalies induced by aerosol direct effects Clim. Dyn. 26 855-64 Lau K M, Kim M K, Kim K M and Lee W S 2010 Enhanced surface warming and accelerated snow melt in the Himalayas and Tibetan Plateau induced by absorbing aerosols Environ. Res. Lett. 5 025204 Li Z, He Y, An W, Song L, Zhang W, Norm C, Cao W, Wilfred H T, Liu H, Wang S, Du J, Xin H and Chang Li 2011 Climate and glacier change in southwestern China during the past several decades Environ. Res. Lett. 6 045404 Qian Y, Flanner M G, Leung L R and Wang W 2011 Sensitivity studies on the impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate Atmos. Chem. Phys. 11 1929-48 Ramanathan V, Li F, Ramana M V, Praveen P S, Kim D, Corrigan C E, Nguyen H, Stone E A, Schauer J J, Carmichael G R, Adhikary B and Yoon S C 2007 Atmospheric brown clouds: Hemispherical and regional variations in long-range transport, absorption, and radiative forcing J. Geophys. Res. 112 D22S21 Sakai A, Nakawo M and Fujita K 1998 Melt rate of ice cliffs on the Lirung Glacier, Nepal Himalayas, 1996 Bull. Glaciol. Res. 16 57-66 Sakai A, Nishimura K, Kadota T and Takeuchi N 2009 Onset of calving at supraglacial lakes on debris covered glaciers of the Nepal Himalayas J. Glaciol. 55 909-17 Scherler D, Bookhagen B and Strecker M R 2011 Spatially variable response of Himalayan glaciers to climate change affected by debris cover Nature Geosci. 4 156-9 Takeuchi N, Kohshima S and Seko K 2001 Structure, formation, darkening process of albedo reducing material (cryoconite) on a Himalayan glacier: a granular algal mat growing on the glacier Arct. Antarct. Alp. Res. 33 115-22 Warren S G and Wiscombe W J 1980 A model for the spectral albedo of snow. II: Snow containing atmospheric aerosols J. Atmos. Sci. 37 2734-45 Wiscombe W J and Warren S G 1980 A model for the spectral albedo of snow. I: Pure snow J. Atmos. Sci. 37 2712-3 Yao T D, Wang Y, Liu S, Pu J, Shen Y and Lu A 2004 Recent glacial retreat in high Asia in China and its impact on water resource in Northwest China Sci. China Ser. D 47 1065-75 Yasunari T J, Bonasoni P, Laj P, Fujita K, Vuillermoz E, Marinoni A, Cristofanelli P, Duchi R, Tartari G and Lau K M 2010 Estimated impact of black carbon deposition during pre-monsoon season from Nepal Climate Observatory--Pyramid data and snow albedo changes over Himalayan glaciers Atmos. Chem. Phys. 10 6603-15 Yasunari T J, Koster R D, Lau K M, Aoki Te, Sud Y C, Yamazaki T, Motoyoshi H and Kodama Y 2011 Influence of dust and black carbon on the snow albedo in the NASA GEOS-5 land surface model J. Geophys. Res. 116 D02210

Renewable Electricity Standards: Good Practices and Design Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, Sadie; Esterly, Sean

2016-01-02

In widespread use globally, renewable electricity standards (RES) are one of the most widely adopted renewable energy policies and a critical regulatory vehicle to accelerate renewable energy deployment. This policy brief provides an introduction to key RES design elements, lessons from country experience, and support resources to enable more detailed and country-specific RES policy design.

Reply to "Comment on `Protecting bipartite entanglement by quantum interferences' "

NASA Astrophysics Data System (ADS)

Das, Sumanta; Agarwal, G. S.

2018-03-01

In a recent Comment Nair and Arun, Phys. Rev. A 97, 036301 (2018), 10.1103/PhysRevA.97.036301, it was concluded that the two-qubit entanglement protection reported in our work [Das and Agarwal, Phys. Rev. A 81, 052341 (2010), 10.1103/PhysRevA.81.052341] is erroneous. While we acknowledge the error in analytical results on concurrence when dipole matrix elements were unequal, the essential conclusions on entanglement protection are not affected.

ERRATUM: Papers published in incorrect sections

NASA Astrophysics Data System (ADS)

2004-04-01

A number of J. Phys. A: Math. Gen. articles have mistakenly been placed in the wrong subject section in recent issues of the journal. We would like to apologize to the authors of these articles for publishing their papers in the Fluid and Plasma Theory section. The correct section for each article is given below. Statistical Physics Issue 4: Microcanonical entropy for small magnetizations Behringer H 2004 J. Phys. A: Math. Gen. 37 1443 Mathematical Physics Issue 9: On the solution of fractional evolution equations Kilbas A A, Pierantozzi T, Trujillo J J and Vázquez L 2004 J. Phys. A: Math. Gen. 37 3271 Quantum Mechanics and Quantum Information Theory Issue 6: New exactly solvable isospectral partners for PT-symmetric potentials Sinha A and Roy P 2004 J. Phys. A: Math. Gen. 37 2509 Issue 9: Symplectically entangled states and their applications to coding Vourdas A 2004 J. Phys. A: Math. Gen. 37 3305 Classical and Quantum Field Theory Issue 6: Pairing of parafermions of order 2: seniority model Nelson C A 2004 J. Phys. A: Math. Gen. 37 2497 Issue 7: Jordan-Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization Mota R D, Xicoténcatl M A and Granados V D 2004 J. Phys. A: Math. Gen. 37 2835 Issue 9: Could only fermions be elementary? Lev F M 2004 J. Phys. A: Math. Gen. 37 3285

Postlingual adult performance in noise with HiRes 120 and ClearVoice Low, Medium, and High.

PubMed

Holden, Laura K; Brenner, Christine; Reeder, Ruth M; Firszt, Jill B

2013-11-01

The study's objectives were to evaluate speech recognition in multiple listening conditions using several noise types with HiRes 120 and ClearVoice (Low, Medium, High) and to determine which ClearVoice program was most beneficial for everyday use. Fifteen postlingual adults attended four sessions; speech recognition was assessed at sessions 1 and 3 with HiRes 120 and at sessions 2 and 4 with all ClearVoice programs. Test measures included sentences presented in restaurant noise (R-SPACE), in speech-spectrum noise, in four- and eight-talker babble, and connected discourse presented in 12-talker babble. Participants completed a questionnaire comparing ClearVoice programs. Significant group differences in performance between HiRes 120 and ClearVoice were present only in the R-SPACE; performance was better with ClearVoice High than HiRes 120. Among ClearVoice programs, no significant group differences were present for any measure. Individual results revealed most participants performed better in the R-SPACE with ClearVoice than HiRes 120. For other measures, significant individual differences between HiRes 120 and ClearVoice were not prevalent. Individual results among ClearVoice programs differed and overall preferences varied. Questionnaire data indicated increased understanding with High and Medium in certain environments. R-SPACE and questionnaire results indicated an advantage for ClearVoice High and Medium. Individual test and preference data showed mixed results between ClearVoice programs making global recommendations difficult; however, results suggest providing ClearVoice High and Medium and HiRes 120 as processor options for adults willing to change settings. For adults unwilling or unable to change settings, ClearVoice Medium is a practical choice for daily listening.

Immunomodulatory effects of high-protein diet with resveratrol supplementation on radiation-induced acute-phase inflammation in rats.

PubMed

Kim, Kyoung-Ok; Park, HyunJin; Chun, Mison; Kim, Hyun-Sook

2014-09-01

We hypothesized that a high-protein diet and/or resveratrol supplementation will improve acute inflammatory responses in rats after receiving experimental abdominal radiation treatment (ART). Based on our previous study, the period of 10 days after ART was used as an acute inflammation model. Rats were exposed to a radiation dose of 17.5 Gy and were supplied with a control (C), 30% high-protein diet (HP), resveratrol supplementation (RES), or HP with RES diet ([HP+RES]). At day 10 after ART, we measured profiles of lipids, proteins, and immune cells in blood. The levels of clusters of differentiating 4(+) (CD4(+)) cells and regulatory T cells, serum proinflammatory cytokines, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine were also measured. ART caused significant disturbances of lipid profiles by increasing triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), and decreasing high-density lipoprotein cholesterol. The proinflammatroy cytokine levels were also increased by ART. All the experimental diets (HP, RES, and [HP+RES]) significantly decreased levels of TG, monocytes, proinflammatory cytokines, and 8-OHdG, whereas the platelet counts were increased. In addition, the HP and [HP+RES] diets decreased the concentrations of plasma LDL-C and total cholesterol. Also, the HP and RES diets decreased regulatory T cells compared with those of the control diet in ART group. Further, the HP diet led to a significant recovery of white blood cell counts, as well as increased percentages of lymphocyte and decreased percentages of neutrophils. In summary, RES appeared to be significantly effective in minimizing radiation-induced damage to lipid metabolism and immune responses. Our study also demonstrated the importance of dietary protein intake in recovering from acute inflammation by radiation.

A regulatory network to segregate the identity of neuronal subtypes.

PubMed

Lee, Seunghee; Lee, Bora; Joshi, Kaumudi; Pfaff, Samuel L; Lee, Jae W; Lee, Soo-Kyung

2008-06-01

Spinal motor neurons (MNs) and V2 interneurons (V2-INs) are specified by two related LIM-complexes, MN-hexamer and V2-tetramer, respectively. Here we show how multiple parallel and complementary feedback loops are integrated to assign these two cell fates accurately. While MN-hexamer response elements (REs) are specific to MN-hexamer, V2-tetramer-REs can bind both LIM-complexes. In embryonic MNs, however, two factors cooperatively suppress the aberrant activation of V2-tetramer-REs. First, LMO4 blocks V2-tetramer assembly. Second, MN-hexamer induces a repressor, Hb9, which binds V2-tetramer-REs and suppresses their activation. V2-INs use a similar approach; V2-tetramer induces a repressor, Chx10, which binds MN-hexamer-REs and blocks their activation. Thus, our study uncovers a regulatory network to segregate related cell fates, which involves reciprocal feedforward gene regulatory loops.

Recycling Endosomes of Polarized Epithelial Cells Actively Sort Apical and Basolateral Cargos into Separate Subdomains

PubMed Central

Thompson, Anthony; Nessler, Randy; Wisco, Dolora; Anderson, Eric; Winckler, Bettina

2007-01-01

The plasma membranes of epithelial cells plasma membranes contain distinct apical and basolateral domains that are critical for their polarized functions. However, both domains are continuously internalized, with proteins and lipids from each intermixing in supranuclear recycling endosomes (REs). To maintain polarity, REs must faithfully recycle membrane proteins back to the correct plasma membrane domains. We examined sorting within REs and found that apical and basolateral proteins were laterally segregated into subdomains of individual REs. Subdomains were absent in unpolarized cells and developed along with polarization. Subdomains were formed by an active sorting process within REs, which precedes the formation of AP-1B–dependent basolateral transport vesicles. Both the formation of subdomains and the fidelity of basolateral trafficking were dependent on PI3 kinase activity. This suggests that subdomain and transport vesicle formation occur as separate sorting steps and that both processes may contribute to sorting fidelity. PMID:17494872

Renewable energy sources in Bulgaria: Current state and trends

NASA Astrophysics Data System (ADS)

Kolev, K.

The over-dependency of Bulgaria on imported fuel stressed the importance of developing a new energy strategy based on energy saving which includes also using renewable energy sources (RES). The target is the substitution of at least 2 percent of the real primary energy consumption with RES by 2010. The author gives a generalized analysis of the available RES in Bulgaria -solar, wind, geothermal, biomass and mini-hydraulic. The potentialities of each source for its usage as a suitable energy supply are pointed out, as well as the current status of research and implementation work, problems connected with legislation, financing and production of particular facilities. The governmental policy concerning RES is considered briefly. A description is given to the project 'Technical and Economical Assessment of Possibilities for Expansion of the RES-part in the Energy Balance of the Country' developed and started in 1994 in the framework of the PHARE program.

[Comparison of the accuracy of rectal endoscopic sonography and magnetic resonance imaging in the diagnosis of colorectal endometriosis].

PubMed

Kanté, F; Belghiti, J; Roseau, G; Thomassin-Naggara, I; Bazot, M; Daraï, E; Ballester, M

2017-03-01

To compare the accuracy of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) for the diagnosis of colorectal endometriosis. In retrospective study, 407 patients operated on service of gynecology of Tenon hospital for deep endometriosis with suspected colorectal involvement. All patients underwent MRI and then RES. In the study, 239 patients (59%) had colorectal endometriosis which were diagnosed with the histology. The sensitivity, specificity, positive and negative predictive value (PPV and NPV) of RES and MRI for the diagnosis of colorectal endometriosis were respectively 92%, 87%, 91%, 88% and 85%, 88%, 91%, 80%. The accuracy of RES was not significantly different than MRI (90% versus 86%, P=0.09). RES is a good exam to diagnose colorectal endometriosis. It is able to improve diagnosis performances. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Binding of resveratrol with sodium caseinate in aqueous solutions.

PubMed

Acharya, Durga P; Sanguansri, Luz; Augustin, Mary Ann

2013-11-15

The interaction between resveratrol (Res) and sodium caseinate (Na-Cas) has been studied by measuring fluorescence quenching of the protein by resveratrol. Quenching constants were determined using Stern-Volmer equation, which suggests that both dynamic and static quenching occur between Na-Cas and Res. Binding constants for the complexation between Na-Cas and Res were determined at different temperatures. The large binding constants (3.7-5.1×10(5)M(-1)) suggest that Res has strong affinity for Na-Cas. This affinity decreases as the temperature is raised from 25 to 37°C. The binding involves both hydrogen bonding and hydrophobic interaction, as suggested by negative enthalpy change and positive entropy change for the binding reaction. The present study indicates that Na-Cas, a common food protein, may be used as a carrier of Res, a bioactive polyphenol which is insoluble in both water and oils. Copyright © 2013 Elsevier Ltd. All rights reserved.

A comparison of three radiation models for the calculation of nozzle arcs

NASA Astrophysics Data System (ADS)

Dixon, C. M.; Yan, J. D.; Fang, M. T. C.

2004-12-01

Three radiation models, the semi-empirical model based on net emission coefficients (Zhang et al 1987 J. Phys. D: Appl. Phys. 20 386-79), the five-band P1 model (Eby et al 1998 J. Phys. D: Appl. Phys. 31 1578-88), and the method of partial characteristics (Aubrecht and Lowke 1994 J. Phys. D: Appl.Phys. 27 2066-73, Sevast'yanenko 1979 J. Eng. Phys. 36 138-48), are used to calculate the radiation transfer in an SF6 nozzle arc. The temperature distributions computed by the three models are compared with the measurements of Leseberg and Pietsch (1981 Proc. 4th Int. Symp. on Switching Arc Phenomena (Lodz, Poland) pp 236-40) and Leseberg (1982 PhD Thesis RWTH Aachen, Germany). It has been found that all three models give similar distributions of radiation loss per unit time and volume. For arcs burning in axially dominated flow, such as arcs in nozzle flow, the semi-empirical model and the P1 model give accurate predictions when compared with experimental results. The prediction by the method of partial characteristics is poorest. The computational cost is the lowest for the semi-empirical model.

Reynolds number effects on the single-mode Richtmyer-Meshkov instability.

PubMed

Walchli, B; Thornber, B

2017-01-01

The Reynolds number effects on the nonlinear growth rates of the Richtmyer-Meshkov instability are investigated using two-dimensional numerical simulations. A decrease in Reynolds number gives an increased time to reach nonlinear saturation, with Reynolds number effects only significant in the range Re<256. Within this range there is a sharp change in instability properties. The bubble and spike amplitudes move towards equal size at lower Reynolds numbers and the bubble velocities decay faster than predicted by Sohn's model [S.-I. Sohn, Phys. Rev. E 80, 055302 (2009)PLEEE81539-375510.1103/PhysRevE.80.055302]. Predicted amplitudes show reasonable agreement with the existing theory of Carles and Popinet [P. Carles and S. Popinet, Phys. Fluids Lett. 13, 1833 (2001)10.1063/1.1377863; Eur. J. Mech. B 21, 511 (2002)EJBFEV0997-754610.1016/S0997-7546(02)01199-8] and Mikaelian [K. O. Mikaelian, Phys. Rev. E 47, 375 (1993)1063-651X10.1103/PhysRevE.47.375; K. O. Mikaelian, Phys. Rev. E 87, 031003 (2013)PLEEE81539-375510.1103/PhysRevE.87.031003], with the former being the closest match to the current computations.

Magnetic and structural X-ray dichroïsms of metallic multilayers

NASA Astrophysics Data System (ADS)

Pizzini, Stefania; Fontaine, A.; Baudelet, F.; Minr, S.; Giorgetti, C.; Dartyge, E.; Bobo, J. F.; Piecuch, M.

1995-05-01

Fe/Cu and Co/Cu multilayers are intensively studied because of their exceptional magnetic properties, i.e., their giant magnetoresistance and the oscillations of the magnetic coupling between magnetic layers as a function of the thickness of the copper spacer [S.S. Parkin et al., Phys. Rev. Lett. 66 (1991) 2152; F. Petroff et al., Phys. Rev. B 44 (1991) 5355]. Spectroscopic approaches to the understanding of the coupling of ferromagnetic layers through a noble metal layer have been recently introduced, in particular spin-resolved photoemission [N.B. Brookes et al., Phys. Rev. Lett. 67 (1991) 354; C. Carbone et al., PRL 71 (1993) 2805] inverse photoemission [J.E. Ortega et al., Phys. Rev. Lett. 69 (1992) 844; Phys. Rev. B 47 (1993) 1540] and magnetic circular dichroism [S. Pizzini et al., MRS Symp. Proc., vol. 313 (1993); M.G. Samant et al. Phys. Rev. Lett. 72 (1994) 2152; S. Pizzini et al., Phys. Rev. Lett. 74 (1995) 1470]. X-ray absorption spectroscopy appears to be effective both for determination of the local structure, specific to the bidimensionality of the system but also for the electron symmetry-dependent evaluation of the spin polarisation of the noble metal as well as the magnetic element.

Fully relativistic B-spline R-matrix calculations for electron collisions with xenon

NASA Astrophysics Data System (ADS)

Bartschat, Klaus; Zatsarinny, Oleg

2009-05-01

We have applied our recently developed fully relativistic Dirac B-spline R-matrix (DBSR) code [1] to calculate electron scattering from xenon atoms. Results from a 31-state close-coupling model for the excitation function of the metastable (5p^5 6s) J=0,2 states show excellent agreement with experiment [2], thereby presenting a significant improvement over the most sophisticated previous Breit-Pauli calculations [3,4]. This allows for a detailed and reliable analysis of the resonance structure. The same model is currently being used to calculate electron-impact excitation from the metastable J=2 state. The results will be compared with recent experimental data [5] and predictions from other theoretical models [6,7]. [1] O. Zatsarinny and K. Bartschat, Phys. Rev. A 77 (2008) 062701. [2] S. J. Buckman et al., J. Phys. B 16 (1983) 4219. [3] A. N. Grum-Grzhimailo and K. Bartschat, J. Phys. B 35 (2002) 3479. [4] M. Allan et al., Phys. Rev. A 74 (2006) 030701(R). [5] R. O. Jung et al., Phys. Rev. A 72 (2005) 022723. [6] R. Srivastava et al., Phys. Rev. A 74 (2006) 012715. [7] J. Jiang et al., J. Phys. B 41 (2008) 245204.

Changing Mindsets to Transform Security: Leader Development for an Unpredictable and Complex World

DTIC Science & Technology

2013-01-01

fields of phys- ical science, the amount of information is doubling every one to two years, meaning that more than half of what a college student has...beyond a review of current events or it being at a “ informational ” level. Naval War College Professor Mackubin Owens stated in 2006, that, The new... information technology in education and training underpinned by a sta- ble and experienced academic community that can support the exponential growth

Multiplicity-dependent and nonbinomial efficiency corrections for particle number cumulants

NASA Astrophysics Data System (ADS)

Bzdak, Adam; Holzmann, Romain; Koch, Volker

2016-12-01

In this article we extend previous work on efficiency corrections for cumulant measurements [Bzdak and Koch, Phys. Rev. C 86, 044904 (2012), 10.1103/PhysRevC.86.044904; Phys. Rev. C 91, 027901 (2015), 10.1103/PhysRevC.91.027901]. We will discuss the limitations of the methods presented in these papers. Specifically we will consider multiplicity dependent efficiencies as well as nonbinomial efficiency distributions. We will discuss the most simple and straightforward methods to implement those corrections.

Reply to "Comment on `Troublesome aspects of the Renyi-MaxEnt treatment' "

NASA Astrophysics Data System (ADS)

Plastino, A.; Rocca, M. C.; Pennini, F.

2017-11-01

This Reply is intended as a refutation of the preceding Comment [Oikonomou and Bagci, Phys. Rev. E 96, 056101 (2017), 10.1103/PhysRevE.96.056101] on our paper [Plastino et al., Phys. Rev. E 94, 012145 (2016)., 10.1103/PhysRevE.94.012145]. We show that the Tsallis probability distribution of our paper does not coincide with the Tsallis distribution studied by Oikonomou and Bagci. Consequently, their findings do not apply to our paper.

Reply to "Comment on 'Troublesome aspects of the Renyi-MaxEnt treatment' ".

PubMed

Plastino, A; Rocca, M C; Pennini, F

2017-11-01

This Reply is intended as a refutation of the preceding Comment [Oikonomou and Bagci, Phys. Rev. E 96, 056101 (2017)10.1103/PhysRevE.96.056101] on our paper [Plastino et al., Phys. Rev. E 94, 012145 (2016).1539-375510.1103/PhysRevE.94.012145]. We show that the Tsallis probability distribution of our paper does not coincide with the Tsallis distribution studied by Oikonomou and Bagci. Consequently, their findings do not apply to our paper.

ERRATUM: High-resolution electron spectroscopy of the 1s23lnl' Be-like series in oxygen and neon. Test of theoretical data: I. Experimental method and theoretical background

NASA Astrophysics Data System (ADS)

Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.

2003-02-01

The J. Phys. B publishing team would like to apologize to the authors of the above paper. In this paper, references [42] and [43] were printed incorrectly. The correct references are: [42] Bordenave-Montesquieu A, Gleizes A and Benoit-Cattin P 1982 Phys. Rev. A 25 245-67 [43] Bordenave-Montesquieu A et al 1987 J. Phys. B: At. Mol. Phys. 20 L695-703.

Calculation of the Gibbs Free Energy of Solvation and Dissociation of HCl in Water via Monte Carlo Simulations and Continuum Solvation Models

DTIC Science & Technology

2013-01-01

Narten, J. Chem. Phys., 1975, 63, 3624–3631. 10 A. Botti, F. Bruni, S. Imberti, M. A. Ricci and A. K. Soper , J. Chem. Phys., 2004, 121, 7840–7848. 11 D...10478. 48 I. Harsányi and L. Pusztai, J. Phys.: Condens. Matter, 2005, 17, S59–S65. 49 A. Botti, F. Bruni, M. A. Ricci and A. K. Soper , J. Chem. Phys

Multiplicity-dependent and nonbinomial efficiency corrections for particle number cumulants

DOE PAGES

Bzdak, Adam; Holzmann, Romain; Koch, Volker

2016-12-19

Here, we extend previous work on efficiency corrections for cumulant measurements [Bzdak and Koch, Phys. Rev. C 86, 044904 (2012)PRVCAN0556-281310.1103/PhysRevC.86.044904; Phys. Rev. C 91, 027901 (2015)PRVCAN0556-281310.1103/PhysRevC.91.027901]. We will then discuss the limitations of the methods presented in these papers. Specifically we will consider multiplicity dependent efficiencies as well as nonbinomial efficiency distributions. We will discuss the most simple and straightforward methods to implement those corrections.

Re-inhabiting place in contemporary rural communities: Moving toward a critical pedagogy of place

NASA Astrophysics Data System (ADS)

Huffling, Lacey D.; Carlone, Heidi B.; Benavides, Aerin

2017-03-01

Heather Zimmerman and Jennifer Weible's (Cult Stud Sci Educ, 2016) use of place-based pedagogy in high school science education honors their participants' lived experiences and the rural communities from which they come. They raise an unresolved tension in their findings: Why did the youth in their study, who clearly learned a lot about the local watershed, not feel empowered or knowledgeable enough to propose collective, action-oriented strategies to address the poor quality of the water? We use this tension as a focus point of our response, drawing on one author's (Huffling's) biography and David Gruenewald's (Educ Res 32:3-12, 2003. doi: 10.3102/0013189X032004003) critical pedagogy of place to re-imagine the curriculum that Zimmerman and Weible describe. We provide strategies that align with Gruenewald's (2003) constructs of decolonization and reinhabitation that could promote youths' collective empowerment.

PREFACE: Classical density functional theory methods in soft and hard matter Classical density functional theory methods in soft and hard matter

NASA Astrophysics Data System (ADS)

Haataja, Mikko; Gránásy, László; Löwen, Hartmut

2010-08-01

Herein we provide a brief summary of the background, events and results/outcome of the CECAM workshop 'Classical density functional theory methods in soft and hard matter held in Lausanne between October 21 and October 23 2009, which brought together two largely separately working communities, both of whom employ classical density functional techniques: the soft-matter community and the theoretical materials science community with interests in phase transformations and evolving microstructures in engineering materials. After outlining the motivation for the workshop, we first provide a brief overview of the articles submitted by the invited speakers for this special issue of Journal of Physics: Condensed Matter, followed by a collection of outstanding problems identified and discussed during the workshop. 1. Introduction Classical density functional theory (DFT) is a theoretical framework, which has been extensively employed in the past to study inhomogeneous complex fluids (CF) [1-4] and freezing transitions for simple fluids, amongst other things. Furthermore, classical DFT has been extended to include dynamics of the density field, thereby opening a new avenue to study phase transformation kinetics in colloidal systems via dynamical DFT (DDFT) [5]. While DDFT is highly accurate, the computations are numerically rather demanding, and cannot easily access the mesoscopic temporal and spatial scales where diffusional instabilities lead to complex solidification morphologies. Adaptation of more efficient numerical methods would extend the domain of DDFT towards this regime of particular interest to materials scientists. In recent years, DFT has re-emerged in the form of the so-called 'phase-field crystal' (PFC) method for solid-state systems [6, 7], and it has been successfully employed to study a broad variety of interesting materials phenomena in both atomic and colloidal systems, including elastic and plastic deformations, grain growth, thin film growth, solid-liquid interface properties, glassy dynamics, nucleation and growth, and diffusive phase transformations at the nano- and mesoscales [8-16]. The appealing feature of DDFT (as applied to solid-state systems) is that it automatically incorporates diffusive dynamics with atomic scale spatial resolution, and it naturally incorporates multiple components, elastic strains, dislocations, free surfaces, and multiple crystalline orientations; all of these features are critical in modeling the behavior of solid-state systems. Similarities between the problems of interest to the two communities and the complementary nature of the methods they apply suggest that a direct interaction between them should be highly beneficial for both parties. Here we summarize some of the discussions during a three-day CECAM workshop in Lausanne (21-23 October 2009) which was organized in order to bring together researchers from the complex fluids and materials science communities and to foster the exchange of ideas between these two communities. During the course of the workshop, several open problems relevant to both fields (DFT and PFC) were identified, including developing better microscopically-informed density functionals, incorporating stochastic fluctuations, and accounting for hydrodynamic interactions. The goal of this special issue is to highlight recent progress in DFT and PFC approaches, and discuss key outstanding problems for future work. The rest of this introductory paper is organized as follows. In section 2, we give a brief overview of the current research topics addressed in this special issue. Then, in section 3, we present a collection of outstanding problems, which have been identified as important for further developments of the two fields and intensely debated at the CECAM workshop. Finally, we close the paper with a few concluding remarks. 2. Research topics addressed in this special issue This special issue consists of research papers that cover a broad range of interesting subjects, about a half of which are related to the theoretical materials science community and the other half came from the soft-matter community. We begin by discussing papers related to PFC. Diverse subjects related to the phase-field crystal model include exciting topics such as predicting/controlling the equilibrium phase behavior [19, 18, 17] and kinetics of epitaxial island formation on nano-membranes [20]. Moreover, phase-field crystal modeling has proved to be very successful in simulating homogeneous and heterogeneous crystal nucleation and growth, and several aspects of these phenomena are discussed in this issue [18, 21]. Finally, it is shown how to incorporate additional orientational degrees of freedom within the PFC approach to model liquid crystals [22]. On the DFT side, the other papers in this special issue deal with problems associated with advanced DFT techniques and applications. The existence of a structural instability in sub-critical crystalline fluctuations in a supercooled liquid within a square-gradient theory is discussed in [23]. Fundamental measure theory for hard-body systems is improved by discussing a correction term in detail, as discussed in [24]. A mean-field-like density functional for charges is applied to the effective interaction between charged colloids obtained within a cell model [25]. The remaining articles provide fundamental insight into how to supplement DDFT-type methods with hydrodynamics [26, 27], highlight the role of the projection operator technique in deriving dynamical density functional theories [28], and demonstrate how perturbation methods can be employed to compute the properties of solid-liquid interfaces [29]. This particular collection of papers demonstrates rather convincingly the significant potential that classical density functional techniques possess in modeling complex systems built of either soft or hard matter (or combinations thereof). While the PFC approach offers a simple and appealing means to simulate evolving microstructures in spatially extended system with atomic scale spatial resolution over diffusive time scales, DFT provides both its theoretical underpinning and (hopefully) the means to construct microscopically more quantitative density functionals for use in engineering materials. Outstanding issues within the PFC and DFT approaches, discussed next, will provide further opportunities for interactions between the PFC and DFT communities. 3. Important open issues and exciting avenues for further research In the following we summarize some of the exciting topics for future research, which were discussed during the CECAM workshop. They concern both fundamental problems and applications, all within the framework of DFT and PFC. Addressing these issues will provide a framework for future work in these two overlapping fields. (a) How to construct a reliable density functional (DF) for soft repulsions? Most of the recent developments in classical density functional theory were focussed on hard-sphere-like interactions in the framework of fundamental-measure-theory (FMT) [30-33]. While this approach can be extended to additive and nonadditive mixtures [34, 35] and to non-spherical hard objects [36, 37], it is much more difficult to include soft-core interactions, such as inverse-power-law pair-potentials. There have been attempts to include those, mainly using the Ramakrishnan-Yussouff [38] or the weighted-density [39-41] approximation, or other modifications (see e.g., [42, 43]), but the accuracy of these functionals are inferior to that of FMT for hard spheres. Clearly the FMT of Rosenfeld needs an extension for the hard-core Coulomb system. A complementary approach is to start from a density functional for hard orientable objects [36] and to integrate out the orientational degrees of freedom. This would lead to a softened effective repulsion between spherical objects. We mention finally that in the extreme limit of ultrasoft pair potentials, which are penetrable, the mean-field approximation provides a reliable functional [44]. (b) How to construct a reliable DF beyond perturbation theory? This is the key to developing accurate, predictive functionals for use in materials science problems. Typically an attractive tail in the interparticle interaction is treated within thermodynamic hard-sphere perturbation theory [45, 46], in most cases at the mean-field level. As this perturbative approach is only justified for weak attraction strengths, there is a great need to go beyond this perturbation theory. A general non-perturbative route, which could be helpful here, is to consider a functional for a mixture and reducing it to an effective one-component system. Following this idea, for example effective depletion attractions can be modeled for a one-component system by starting from the binary Asakura-Oosawa functional [34, 35]. This idea still needs to be exploited in a more general sense, i.e. for more general cross-interactions in the mixture. It could also be combined with the idea of using non-spherical hard objects and integrating out the orientational degrees of freedom. (c) How to apply the fundamental measure theory to the full phase diagram of lyotropic liquid crystals? There are already density-functional investigations of liquid-crystal phases of hard spherocylinders [47, 48], but the novel fundamental-measure-theory which was recently proposed for non-spherical objects[36] has never been applied to this problem. In fact, this new functional now needs numerical evaluation for liquid-crystal phases different from isotropic and nematic ones, such as smectic, columnar, plastic crystalline and full orientational ordered crystalline phases [49, 50]. This is mainly a pure numerical resolution problem since the density fields are sharply peaked in the solid phases and need enough grid points, which is at the moment a rather formidable challenge in three spatial dimensions. However, if only orientational degrees of freedoms are considered, the computational effort is greatly reduced; see, e.g., [36, 51, 52]. (d) The role of fluctuations in DDFT and PFC. There is a continuing debate about the role of noise in the dynamical density functional theory (see e.g. [53]) and correspondingly also in the phase-field crystal models. Derivations of DDFT from the Smoluchowski level [54] and also within the projection operator technique [5] quite naturally lead to a deterministic equation without any noise. Clearly this is an approximation, which becomes problematic in the vicinity of a critical point or in the case of nucleation problems, where the system has to leave a metastable minimum of the free energy; in the former case, fluctuations are required in order to capture the correct critical behavior (i.e., critical exponents), while in the latter case, fluctuations are needed to establish an escape route of the system from a metastable phase. Other approaches add noise on a more phenomenological level. However, the actual strength of the noise, though fundamentally correlated with the thermal energy, is not known exactly and is treated in most applications as a phenomenological fit parameter; see, e.g., [55, 56]. This problem is a very fundamental one, and, of course, shared by the DDFT and PFC approaches. In more general terms, the addition of noise to the equation of motion in continuum models is not without conceptual difficulties (see [57]), even if noise is properly discretized in the course of the numerical integration. With the noise added, the equilibrium physical properties of the system change. Furthermore, transformation kinetics generally depend on the spatial and temporal steps, and in the limit of infinitely small steps an ultraviolet 'catastrophe' (divergence of the free energy) may occur. Evidently, an 'ultraviolet cut-off', i.e. filtering out the highest frequencies, is required to regularize the unphysical singularity. In the PFC case, a straightforward choice for the cut-off length is the interparticle distance, which is expected to remove the unphysical, small wavelength fluctuations [58, 16, 59, 18]. Perhaps a more elegant way to handle this problem is via renormalizing the model parameters so that with noise one recovers the 'bare' physical properties (see the application of this approach for the Swift-Hohenberg model in [60]). However, further systematic investigations are needed in order to settle this issue. (e) The need to clarify the role of the adiabatic approximation. While DDFT can be derived from more microscopic equations, such as the Smoluchowski equation [54] or the Langevin equations [61] for the individual particles, a major approximation is invoked in the derivation, namely the so-called 'adiabatic approximation'. This approximation assumes that all other observables relax much faster than the one-particle density field [5]. Therefore, the nonequilibrium correlations are replaced by equilibrium ones corresponding to an inhomogeneous reference one-particle density [54]. This enables one to formulate the theory in terms of the time-dependent one-particle density field alone. What is still needed here is a more general theory which provides the next-leading order beyond the adiabatic approximation. This improved theory would not only provide more fundamental insight into the DDFT itself; it would also pave the way to many applications where the simpleDDFT fails. (f) How to apply and exploit DDFT for active matter? The collective behavior of self-propelled particles with internal driving motors is a topic of active research [62, 62]. Given that the particle dynamics can be described in terms of driven Brownian motion, a dynamical density functional theory can be derived in a straightforward manner. In a first application, DDFT was employed to describe aggregation phenomena near system boundaries for driven rod-like colloidal particles [64]. The potential of DDFT for 'active' particles should be exploited more in the future, as it provides a microscopic approach to investigate nonequilibrium effects, such as swarming and jamming. (g) How to construct a PFC model for inhomogeneous liquid crystals? The traditional PFC model [6, 7] describes a two-dimensional one-component solid phase by a single inhomogeneous sinusoidal density field. The PFC approach has been generalized to mixtures by including more than a single density field [11] and to anisotropic particles with a fixed orientation [65]. However, it has never been applied to liquid crystals which are made by particles with intrinsic orientational degrees of freedom. Based on discussion during the CECAM workshop, a link towards the PFC model has been elaborated and the corresponding PFC model for liquid crystals was derived, see article [22] in this special issue. The extended PFC model contains both the translational density and the local orientational degree of ordering as well as a local director field. The model exhibits stable isotropic, nematic, smectic A, columnar, plastic crystalline and orientationally ordered crystalline phases and bears therefore much richer phases than the original PFC. A large-scale numerical exploration of this PFC model still needs to be performed. The derivation exploits the connection between DDFT and PFC, which was highlighted in [66] for spherical particles, and is based on recent generalizations of DDFT to rod-like Brownian particles [67, 64]. (h) How to incorporate hydrodynamic interactions between particles in dense driven systems of colloids? In dense colloidal dispersions, hydrodynamic interactions between the particles play a major role in their collective behavior. While these interactions affect neither structural correlations nor the equilibrium phase behavior, they have a profound effect on the dynamics both in equilibrium and non-equilibrium [68]. Recently, DDFT was extended to include hydrodynamic interactions on the pairwise level of the mobility tensors [69]. This kind of DDFT needs more applications as well as a fundamental development towards higher-order mobility tensors beyond the pairwise level or to a description, which includes lubrication forces between colloidal particles at small interparticle separations. (i) How to systematically construct effective, low-frequency representations from DFT/DDFT? Given an accurate and predictive density functional, which incorporates interaction potentials between the constituent species in a multi-component system, building an effective description would be highly desirable as it would provide an alternative to purely atomistic approaches (e.g., molecular dynamics simulations) and enable the simulation of quantitative, microscopically-informed, continuum systems across diffusive time scales. The first challenge, of course, is the development of such functionals, as already discussed in item (b) above. Once this challenge has been overcome, the next step would be to project out the dynamics of the relevant degrees of freedom from the full DDFT description. Physically, one would expect that the shape of a single peak in the density would relax much faster than, say, the distance between peak centers. Therefore, it should be possible to `slave' the high-frequency modes associated with the peak shapes to the more slowly evolving modes with low spatial frequencies. (j) How to build numerically efficient, quantitative PFC models for a broad spectrum of metallic materials? Viewed as an extension of the traditional phase-field method (see, e.g., [70-74]. for comprehensive reviews), PFC incorporates microscopic physics (crystal symmetry, grain orientation, topological defects) in a phenomenological manner. A practical issue in numerically integrating the dynamic PFC equation is that the grid spacing is constrained to be a fraction of the lattice spacing (typically Δ x ~ a/8), making large-scale simulations challenging in three spatial dimensions. It is thus highly desirable to develop a methodology that would allow one to tune important materials parameters such as crystal symmetry, lattice spacing, elastic constants, surface energies and stresses, dislocation core energy, and dislocation mobility, without sacrificing numerical efficiency. The issue of constructing PFC free energies, which give rise to a given crystal symmetry, has been addressed very recently; see, e.g., [17-19]. Going beyond the question of crystal symmetry, an appealing possibility is to further develop the so-called amplitude equation approach [75-77]., in which the density field is essentially expressed in terms of slowly-varying envelope functions (i.e., amplitudes), modulated by the fundamental spatial periodicity of the density. In fact, it has been demonstrated recently that such an approach provides a truly multi-scale approach to studying phase transformations in solid-liquid systems [78]. The goal is to construct amplitude equations, which accurately incorporate, e.g., surface tension anisotropies for simulations of solid-solid, solid-liquid, and solid-vapor systems. Alternatively, one can work directly with the PFC density field and introduce additional model parameters which can be fitted so that a required set of physical properties is recovered, such as the properties of the solid-liquid interface in pure iron [79]. (k) How to simulate electronic materials with PFC? Ferroelectrics comprise an interesting class of materials, which undergo a structural phase transformation (typically cubic-to-tetragonal) below a Curie temperature and acquire a non-zero electric polarization. It has been suggested that the manipulation of these polarization domains by means of an external field can be exploited in novel non-volatile memory devices [80, 81]. The PFC approach would present an appealing means to study ferroelectrics exhibiting one or more (ferroic) order parameters, provided that the crystal lattice can be coupled to the local order parameter(s) in a physically-based manner. 4. Concluding remarks The workshop 'Classical density functional theory methods in soft and hard matter' has established the first contact between the soft-matter community working with advanced classical density functional techniques and a theoretical materials science community working with engineering materials and armed with a simple but numerically very efficient dynamical density functional technique, the phase-field crystal method. A large number of common problems have been identified, which represent challenges for both communities during the coming years. This has been borne out by the lively discussions and some of the provocative talks. The organizers think that the workshop proved to be a truly successful event, matching to the high standards of the CECAM workshops, and hope that the workshop will indeed catalyze a long-term interaction between the two communities. As a final note, we would like to emphasize that progress in the areas highlighted in this special issue will positively impact both fields, and we expect that these issues will provide the natural link for collaborations and intellectual exchanges between these traditionally separate-yet-allied fields. In particular, such activities would lead to significant improvements in the applicability and versatility of classical DFT methods in both soft and hard matter systems, for the common benefit of physicists, chemists, and materials scientists. References [1] Evans R 1979 Adv. Phys. 28 143 [2] Oxtoby D W 1991 Liquids, Freezing and the Glass Transition (Session LI (1989) of Les Houches Summer Schools of Theoretical Physics) (Amsterdam: North Holland) p 147 [3] Singh Y 1991 Phys. Rep. 207 351 [4] Löwen H 1994 Phys. Rep. 237 249 [5] Español P and Löwen H 2009 J. Chem. Phys. 131 244101 [6] Elder K R, Katakowski M, Haataja M and Grant M 2002 Phys. Rev. Lett. 88 245701 [7] Elder K R and Grant M 2004 Phys. Rev. E 70 051605 [8] Berry J, Grant M and Elder K R 2006 Phys. Rev. E 73 031609 [9] Stefanovic P, Haataja M and Provatas N 2006 Phys. Rev. Lett. 96 225504 [10] Wu K-A and Karma A 2007 Phys. Rev. B 76 184107 [11] Elder K R, Provatas N, Berry J, Stefanovic P and Grant M 2007 Phys. Rev. B 75 064107 [12] Berry J, Elder K R and Grant M 2008 Phys. Rev. E 77 061506 [13] Huang Z-F and Elder K R 2008 Phys. Rev. Lett. 101 158701 [14] Wu K-A and Voorhees P W 2009 Phys. Rev. B 80 125408 [15] Stefanovic P, Haataja M and Provatas N 2009 Phys. Rev. E 80 046107 [16] Tegze G, Gránásy L, Tóth G I, Podmaniczky F, Jaatinen A, Ala-Nissial T and Pusztai T 2009 Phys. Rev. Lett. 103 035702 [17] Jaatinen A and Ala-Nissila T 2010 Extended phase diagram of the three-dimensional phase field crystal model J. Phys.: Condens. Matter 22 205402 [18] Tóth G I, Tegze G, Pusztai T, Tóth G and Gránásy L 2010 Polymorphism, crystal nucleation and growth in the phase-field crystal model in 2D and 3D J. Phys.: Condens. Matter 22 364101 [19] Wu K-A, Plapp M and Voorhees P 2010 Controlling crystal symmetries in phase-field crystal models J. Phys.: Condens. Matter 22 364102 [20] Elder K R and Huang Z-F 2010 A phase field crystal study of epitaxial island formation on nanomembranes J. Phys.: Condens. Matter 22 364103 [21] Backofen R and Voigt A 2010 A phase-field-crystal approach to critical nuclei J. Phys.: Condens. Matter 22 364104 [22] Löwen H 2010 A phase-field-crystal model for liquid crystals J. Phys.: Condens. Matter 22 364105 [23] Harrowell P 2010 On the existence of a structural instability in sub-critical crystalline fluctuations in a supercooled liquid J. Phys.: Condens. Matter 22 364106 [24] Hansen-Goos H and Mecke K 2010 Tensorial density functional theory for non-spherical hard-body fluids J. Phys.: Condens. Matter 22 364107 [25] Denton A R 2010 Poisson-Boltzmann theory of charged colloids: limits of the cell model for salty suspensions J. Phys.: Condens. Matter 22 364108 [26] Rauscher M 2010 DDFT for Brownian particles and hydrodynamics J. Phys.: Condens. Matter 22 364109 [27] Marini Bettolo Marconi U and Melchionna S 2010 Dynamic density functional theory versus kinetic theory of simple fluids J. Phys.: Condens. Matter 22 364110 [28] Majaniemi S, Provatas N and Nonomura M 2010 Effective model hierarchies for dynamic and static classical density functional theories J. Phys.: Condens. Matter 22 364111 [29] Warshavsky V B and Song X 2010 Perturbation theory for solid-liquid interfacial free energies J. Phys.: Condens. Matter 22 364112 [30] Rosenfeld Y, Schmidt M, Löwen H and Tarazona P 1997 Phys. Rev. E 55 4245 [31] Roth R, Evans R, Lang A and Kahl G 2002 J. Phys: Condens. Matter 14 12063 [32] Tarazona P, Cuesta J A and Martinez-Raton Y 2008 Density Functional Theories of Hard Particle Systems (Springer Lecture Notes in Physics vol 753) (Berlin: Springer) p 247 [33] Roth R 2010 J. Phys: Condens. Matter 22 063102 [34] Schmidt M, Löwen H, Brader J M and Evans R 2000 Phys. Rev. Lett. 85 1934 [35] Schmidt M, Löwen H, Brader J M and Evans R 2002 J. Phys.: Condens. Matter 14 9353 [36] Hansen-Goos H and Mecke K 2009 Phys. Rev. Lett. 102 018302 [37] Esztermann A, Reich H and Schmidt M 2006 Phys. Rev. E 73 011409 [38] Ramakrishnan T V and Yussouff M 1979 Phys. Rev. B 19 2775 [39] Denton A R and Ashcroft N W 1989 Phys. Rev. A 39 4701 [40] Hasegawa M 1994 J. Phys. Soc. Japan 63 2215 [41] Kol A and Laird B B 1997 Mol. Phys. 90 951 [42] van Teeffelen S, Löwen H and Likos C N 2008 J. Phys.: Condens. Matter 20 404217 [43] van Teeffelen S, Hoffmann N, Likos C N and Löwen H 2006 Europhys. Lett. 75 583 [44] Likos C N, Hoffmann N, Löwen H and Louis A A 2002 J. Phys.: Condens. Matter 14 7681 [45] Curtin W A and Ashcroft N W 1986 Phys. Rev. Lett. 56 2775 [46] Likos C N, Németh Z T and Löwen H 1994 J. Phys.: Condens. Matter 6 10965 [47] Poniewierski A and Holyst R 1988 Phys. Rev. Lett. 61 2461 [48] Graf H and Löwen H 1999 J. Phys.: Condens. Matter 11 1435 [49] Bolhuis P and Frenkel D 1997 J. Chem. Phys. 106 666 [50] Frenkel D, Mulder B M and McTague J P 1984 Phys. Rev. Lett. 52 287 [51] Härtel A and Löwen H 2010 J. Phys.: Condens. Matter 22 104112 [52] Härtel A, Blaak R and Löwen H 2010 Towing, breathing, splitting, and overtaking in driven colloidal liquid crystals Phys. Rev. E 81 051703 [53] Archer A J and Rauscher M 2004 J. Phys. A: Math. Gen. 37 9325 [54] Archer A J and Evans R 2004 J. Chem. Phys. 121 4246 [55] Ramos J A P, Granato E, Achim C V, Ying S C, Elder K R and Ala-Nissila T 2008 Phys. Rev. E 78 031109 [56] Hubert J, Cheng M and Emmerich H 2009 J. Phys.: Condens. Matter 21 464108 [57] Plapp M 2010 Philos. Mag. submitted [58] Pusztai T, Tegze G, Tóth G I, Környei L, Bansel G, Fan Z and Gránásy L 2008 J. Phys.: Condens. Matter 20 404205 [59] Tegze G, Bansel G, Tóth G I, Pusztai T, Fan Z and Gránásy L 2009 J. Comput. Phys. 228 1612 [60] Gross N A, Ignatiev M and Chakraborty B 2000 Phys. Rev. E 62 6116 [61] Marconi V M B and Tarazona P 2000 J. Phys.: Condens. Matter 12 A413 [62] Toner J, Tu Y and Ramaswamy S 2005 Ann. Phys. 318 170 [63] Lauga E and Powers T R 2009 Rep. Prog. Phys. 72 096601 [64] Wensink H H and Löwen H 2008 Phys. Rev. E 78 031409 [65] Prieler R, Hubert J, Li D, Verleye B, Haberkern R and Emmerich H 2009 J. Phys.: Condens. Matter 21 464110 [66] van Teeffelen S, Backofen R, Voigt A and Löwen H 2009 Phys. Rev. E 79 051404 [67] Rex M, Wensink H H and Löwen H 2007 Phys. Rev. E 76 021403 [68] Dhont J K G 1996 An Introduction to Dynamics of Colloids (Amsterdam: Elsevier) [69] Rex M and Löwen H 2008 Phys. Rev. Lett. 101 148302 [70] Elder K R, Grant M, Provatas N and Kosterlitz J M 2001 Phys. Rev. E 64 021604 [71] Chen L Q 2002 Annu. Rev. Mat. Res. 32 113 [72] Boettinger W J, Warren J A, Beckermann C and Karma A 2002 Annu. Rev. Mat. Res. 32 163 [73] Gránásy L, Pusztai T and Warren J A 2004 J. Phys.: Condens. Matter 16 R1205 [74] Singer-Loginova I and Singer H M 2008 Rep. Prog. Phys. 71 106501 [75] Goldenfeld N, Athreya B P and Dantzig J A 2005 Phys. Rev. E 72 020601 [76] Yeon D-H, Huang Z-F, Elder K R and Thornton K 2010 Phil. Mag. 90 237 [77] Elder K R, Huang Z-F and Provatas N 2010 Phys. Rev. E 81 011602 [78] Athreya B P, Goldenfeld N, Dantzig J A, Greenwood M and Provatas N 2007 Phys. Rev. E 76 056706 [79] Jaatinen A, Achim C V, Elder K R and Ala-Nissila T 2009 Phys. Rev. E 80 031602 [80] Chu M-W et al 2004 Nat. Mater. 3 87 [81] Rudiger A and Waser J 2008 J. Alloy Compounds 449 2

78 FR 54669 - Draft Environmental Impact Statement for the Proposed RES Americas Moapa Solar Energy Center...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-05

... Environmental Impact Statement for the Proposed RES Americas Moapa Solar Energy Center, Clark County, Nevada... environmental impact statement (DEIS) for the proposed RES Americas Moapa Solar Energy Center on the Moapa River... Progress and on the following Web site: www.MoapaSolarEnergyCenterEIS.com . In order to be fully considered...

Unraveling the Raman Enhancement Mechanism on 1T'-Phase ReS2 Nanosheets.

PubMed

Miao, Peng; Qin, Jing-Kai; Shen, Yunfeng; Su, Huimin; Dai, Junfeng; Song, Bo; Du, Yunchen; Sun, Mengtao; Zhang, Wei; Wang, Hsing-Lin; Xu, Cheng-Yan; Xu, Ping

2018-04-01

2D transition metal dichalcogenides materials are explored as potential surface-enhanced Raman spectroscopy substrates. Herein, a systematic study of the Raman enhancement mechanism on distorted 1T (1T') rhenium disulfide (ReS 2 ) nanosheets is demonstrated. Combined Raman and photoluminescence studies with the introduction of an Al 2 O 3 dielectric layer unambiguously reveal that Raman enhancement on ReS 2 materials is from a charge transfer process rather than from an energy transfer process, and Raman enhancement is inversely proportional while the photoluminescence quenching effect is proportional to the layer number (thickness) of ReS 2 nanosheets. On monolayer ReS 2 film, a strong resonance-enhanced Raman scattering effect dependent on the laser excitation energy is detected, and a detection limit as low as 10 -9 m can be reached from the studied dye molecules such as rhodamine 6G and methylene blue. Such a high enhancement factor achieved through enhanced charge interaction between target molecule and substrate suggests that with careful consideration of the layer-number-dependent feature and excitation-energy-related resonance effect, ReS 2 is a promising Raman enhancement platform for sensing applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analyses of electron runaway in front of the negative streamer channel

NASA Astrophysics Data System (ADS)

Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.; Neubert, T.; Chanrion, O.

2017-08-01

X-ray and γ-ray emissions, observed in correlation with negative leaders of lightning and long sparks of high-voltage laboratory experiments, are conventionally connected with the bremsstrahlung of high-energy runaway electrons (REs). Here we extend a focusing mechanism, analyzed in our previous paper, which allows the electric field to reach magnitudes, required for a generation of significant RE fluxes and associated bremsstrahlung, when the ionization wave propagates in a narrow, ionized channel created by a previous streamer. Under such conditions we compute the production rate of REs per unit streamer length as a function of the streamer velocity and predict that, once a streamer is formed with the electric field capable of producing REs ahead of the streamer front, the ionization induced by the REs is capable of creating an ionized channel that allows for self-sustained propagation of the RE-emitting ionization wave independent of the initial electron concentration. Thus, the streamer coronas of the leaders are probable sources of REs producing the observed high-energy radiation. To prove these predictions, new simulations are planned, which would show explicitly that the preionization in front of the channel via REs will lead to the ionization wave propagation self-consistent with RE generation.

Large-Area CVD-Grown Sub-2 V ReS2 Transistors and Logic Gates.

PubMed

Dathbun, Ajjiporn; Kim, Youngchan; Kim, Seongchan; Yoo, Youngjae; Kang, Moon Sung; Lee, Changgu; Cho, Jeong Ho

2017-05-10

We demonstrated the fabrication of large-area ReS 2 transistors and logic gates composed of a chemical vapor deposition (CVD)-grown multilayer ReS 2 semiconductor channel and graphene electrodes. Single-layer graphene was used as the source/drain and coplanar gate electrodes. An ion gel with an ultrahigh capacitance effectively gated the ReS 2 channel at a low voltage, below 2 V, through a coplanar gate. The contact resistance of the ion gel-gated ReS 2 transistors with graphene electrodes decreased dramatically compared with the SiO 2 -devices prepared with Cr electrodes. The resulting transistors exhibited good device performances, including a maximum electron mobility of 0.9 cm 2 /(V s) and an on/off current ratio exceeding 10 4 . NMOS logic devices, such as NOT, NAND, and NOR gates, were assembled using the resulting transistors as a proof of concept demonstration of the applicability of the devices to complex logic circuits. The large-area synthesis of ReS 2 semiconductors and graphene electrodes and their applications in logic devices open up new opportunities for realizing future flexible electronics based on 2D nanomaterials.

Spectroscopic investigations of the charge-transfer interaction between the drug reserpine and different acceptors: Towards understanding of drug-receptor mechanism

NASA Astrophysics Data System (ADS)

Eldaroti, Hala H.; Gadir, Suad A.; Refat, Moamen S.; Adam, Abdel Majid A.

2013-11-01

The study of the charge-transfer interaction of the drugs may be useful in understanding the drug-receptor interactions and the mechanism of drug action. Structural and thermal stability of charge-transfer (CT) complexes formed between the drug reserpine (Res) as a donor and quinol (QL), picric acid (PA), tetracyanoquinodimethane (TCNQ) or dichlorodicyanobenzoquinone (DDQ) as acceptors were reported. Elemental analysis, electronic absorption, spectrophotometric titration, IR, Raman, 1H NMR and X-ray powder diffraction (XRD) were used to characterize the new products. The thermal stability of the synthesized CT complexes was investigated using thermogravimetric (TG) analyses, and the morphology and particle size of these complexes were obtained from scanning electron microscopy (SEM). The stoichiometry of the complexes (donor:acceptor molar ratio) was determined to be 1:1 for all complexes. Accordingly the formed CT complexes could be formulated as [(Res)(QL)], [(Res)(PA)], [(Res)(TCNQ)] and [(Res)(DDQ)]. It was found that the obtained CT complexes are nanoscale, semi-crystalline particles, thermally stable and formed through spontaneous reaction. The results obtained herein are satisfactory for estimation of drug Res in the pharmaceutical form.

Circulating MicroRNA Responses between 'High' and 'Low' Responders to a 16-Wk Diet and Exercise Weight Loss Intervention.

PubMed

Parr, Evelyn B; Camera, Donny M; Burke, Louise M; Phillips, Stuart M; Coffey, Vernon G; Hawley, John A

2016-01-01

Interactions between diet, physical activity and genetic predisposition contribute to variable body mass changes observed in response to weight loss interventions. Circulating microRNAs (c-miRNAs) may act as 'biomarkers' that are associated with the rate of change in weight loss, and/or play a role in regulating the biological variation, in response to energy restriction. To quantify targeted c-miRNAs with putative roles in energy metabolism and exercise adaptations following a 16 wk diet and exercise intervention in individuals with large (high responders; HiRes) versus small (low responders; LoRes) losses in body mass. From 89 male and female overweight/obese participants who completed the intervention (energy restriction from diet, 250 kcal/d, and exercise, 250 kcal/d), subgroups of HiRes (>10% body mass loss, n = 22) and LoRes (<5% body mass loss, n = 18) were identified. From resting plasma samples collected after an overnight fast pre and post intervention, RNA was extracted, quantified and reverse transcribed. Thirteen c-miRNA selected a priori were analysed using a customised 96-well miScript miRNA PCR Array. Loss of body mass (-11.0 ± 2.3 kg vs. -3.0 ± 1.3 kg; P<0.01) and fat mass (-11.1 ± 2.6 kg vs. -3.9 ± 1.6 kg; P<0.01) was greater for HiRes than LoRes (P<0.001). Expression of c-miR-935 was higher in LoRes compared to HiRes pre- (~47%; P = 0.025) and post- (~100%; P<0.01) intervention and was the only c-miRNA differentially expressed at baseline between groups. The abundance of c-miR-221-3p and -223-3p increased pre- to post-intervention in both groups (~57-69% and ~25-90%, P<0.05). There was a post-intervention increase in c-miR-140 only in LoRes compared to HiRes (~23%, P = 0.016). The differential expression and responses of selected c-miRNAs in overweight/obese individuals to an exercise and diet intervention suggests a putative role for these 'biomarkers' in the prediction or detection of individual variability to weight loss interventions.

Circulating MicroRNA Responses between ‘High’ and ‘Low’ Responders to a 16-Wk Diet and Exercise Weight Loss Intervention

PubMed Central

Parr, Evelyn B.; Camera, Donny M.; Burke, Louise M.; Phillips, Stuart M.; Coffey, Vernon G.; Hawley, John A.

2016-01-01

Background Interactions between diet, physical activity and genetic predisposition contribute to variable body mass changes observed in response to weight loss interventions. Circulating microRNAs (c-miRNAs) may act as ‘biomarkers’ that are associated with the rate of change in weight loss, and/or play a role in regulating the biological variation, in response to energy restriction. Objective To quantify targeted c-miRNAs with putative roles in energy metabolism and exercise adaptations following a 16 wk diet and exercise intervention in individuals with large (high responders; HiRes) versus small (low responders; LoRes) losses in body mass. Methods From 89 male and female overweight/obese participants who completed the intervention (energy restriction from diet, 250 kcal/d, and exercise, 250 kcal/d), subgroups of HiRes (>10% body mass loss, n = 22) and LoRes (<5% body mass loss, n = 18) were identified. From resting plasma samples collected after an overnight fast pre and post intervention, RNA was extracted, quantified and reverse transcribed. Thirteen c-miRNA selected a priori were analysed using a customised 96-well miScript miRNA PCR Array. Results Loss of body mass (-11.0 ± 2.3 kg vs. -3.0 ± 1.3 kg; P<0.01) and fat mass (-11.1 ± 2.6 kg vs. -3.9 ± 1.6 kg; P<0.01) was greater for HiRes than LoRes (P<0.001). Expression of c-miR-935 was higher in LoRes compared to HiRes pre- (~47%; P = 0.025) and post- (~100%; P<0.01) intervention and was the only c-miRNA differentially expressed at baseline between groups. The abundance of c-miR-221-3p and -223-3p increased pre- to post-intervention in both groups (~57–69% and ~25–90%, P<0.05). There was a post-intervention increase in c-miR-140 only in LoRes compared to HiRes (~23%, P = 0.016). Conclusion The differential expression and responses of selected c-miRNAs in overweight/obese individuals to an exercise and diet intervention suggests a putative role for these ‘biomarkers’ in the prediction or detection of individual variability to weight loss interventions. PMID:27101373

On the Runge-Lenz-Pauli vector operator as an aid to the calculation of atomic processes in laboratory and astrophysical plasmas

NASA Astrophysics Data System (ADS)

Hey, J. D.

2015-09-01

On the basis of the original definition and analysis of the vector operator by Pauli (1926 Z. Phys. 36 336-63), and further developments by Flamand (1966 J. Math. Phys. 7 1924-31), and by Becker and Bleuler (1976 Z. Naturforsch. 31a 517-23), we consider the action of the operator on both spherical polar and parabolic basis state wave functions, both with and without direct use of Pauli’s identity (Valent 2003 Am. J. Phys. 71 171-75). Comparison of the results, with the aid of two earlier papers (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641-64, Hey 2007 J. Phys. B: At. Mol. Opt. Phys. 40 4077-96), yields a convenient ladder technique in the form of a recurrence relation for calculating the transformation coefficients between the two sets of basis states, without explicit use of generalized hypergeometric functions. This result is therefore very useful for application to Stark effect and impact broadening calculations applied to high-n radio recombination lines from tenuous space plasmas. We also demonstrate the versatility of the Runge-Lenz-Pauli vector operator as a means of obtaining recurrence relations between expectation values of successive powers of quantum mechanical operators, by using it to provide, as an example, a derivation of the Kramers-Pasternack relation. It is suggested that this operator, whose potential use in Stark- and Zeeman-effect calculations for magnetically confined fusion edge plasmas (Rosato, Marandet and Stamm 2014 J. Phys. B: At. Mol. Opt. Phys. 47 105702) and tenuous space plasmas ( H II regions) has not been fully explored and exploited, may yet be found to yield a number of valuable results for applications to plasma diagnostic techniques based upon rate calculations of atomic processes.

Response to "Comment on `Solitonic and chaotic behaviors for the nonlinear dust-acoustic waves in a magnetized dusty plasma'" [Phys. Plasmas 24, 094701 (2017)

NASA Astrophysics Data System (ADS)

Zhen, Hui-Ling; Tian, Bo; Xie, Xi-Yang; Wu, Xiao-Yu; Wen, Xiao-Yong

2018-02-01

On our previous construction [H. L. Zhen et al., Phys. Plasmas 23, 052301 (2016)] of the soliton solutions of a model describing the dynamics of the dust particles in a weakly ionized, collisional dusty plasma comprised of the negatively charged cold dust particles, hot ions, hot electrons, and stationary neutrals in the presence of an external static magnetic field, Ali et al. [Phys. Plasmas 24, 094701 (2017)] have commented that there exists a different form of Eq. (4) from that shown in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] and that certain interesting phenomena with the dust neutral collision frequency ν0>0 are ignored in Zhen et al. [Phys. Plasmas 23, 052301 (2016)]. In this Reply, according to the transformation given by the Ali et al. [Phys. Plasmas 24, 094701 (2017)] comment, we present some one-, two-, and N-soliton solutions which have not been obtained in the Ali et al. [Phys. Plasmas 24, 094701 (2017)] comment. We point out that our previous solutions in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] are still valid because of the similarity between the two dispersion relations of previous solutions in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] and the solutions presented in this Reply. Based on our soliton solutions in this Reply, it is found that the soliton amplitude is inversely related to Zd and B0, but positively related to md and α, where α refers to the coefficient of the nonlinear term, Zd and md are the charge number and mass of a dust particle, respectively, B0 represents the strength of the external static magnetic field. We also find that the two solitons are always in parallel during the propagation.

Comment on “Theoretical analysis of high-field transport in graphene on a substrate” [J. Appl. Phys. 116, 034507 (2014)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Michael L. P.; Arora, Vijay K., E-mail: vijay.arora@wilkes.edu; Department of Electrical Engineering and Physics, Wilkes University, Wilkes-Barre, Pennsylvania 18766

2014-12-21

In a recent article, Serov et al. [J. Appl. Phys. 116, 034507 (2014)] claim: “This study represents the first time that the high-field behavior in graphene on a substrate was investigated taking into account intrinsic graphene properties,” ignoring the most recent anisotropic distribution function [V. K. Arora et al., J. Appl. Phys. 112, 114330 (2012)] also published in J. Appl. Phys., targeting the same experimental data [V. E. Dorgan et al., Appl. Phys. Lett. 97, 082112 (2010)]. The claim of Serov et al. of being first is refuted and many shortcomings of the hydrodynamic model for a highly quantum andmore » degenerate graphene nanolayer are pointed out.« less

Superconducting and Normal State Properties of OsB2*

NASA Astrophysics Data System (ADS)

Singh, Yogesh; Niazi, A.; Zong, X.; Suh, B. J.; Vannette, M. W.; Prozorov, R.; Johnston, D. C.

2007-03-01

OsB2 is a layered superhard metallic material that was found to superconduct below Tc= 2.1 K.^1 We report the first detailed measurements of the static and dynamic magnetic susceptibilities χ, electrical resistivity, heat capacity Cp, penetration depth, and ^11B NMR on OsB2 to characterize its superconducting and normal state properties. The results confirm that OsB2 is a bulk superconductor below Tc= 2.1 K@. Its properties can be described by a close to weak-coupling s-wave BCS model with an electron-phonon coupling constant λ= 0.4--0.5, δ(0)/(kBTc) 1.9, a small Ginzburg-Landau parameter κ of order 5 or less, and a small zero-temperature critical magnetic field of roughly 500 Oe. The ^11B NMR measurements in the normal state show a nuclear spin-lattice relaxation time T1= 2.1 s at room temperature and a Korringa law with T1T = 610 s.K at lower T, and a correspondingly small T-independent Knight shift. These results indicate a small s character of the conduction electron wave function at the B site at the Fermi level. Our results will be compared to corresponding data for MgB2.1. J. K. Vandenberg et al., Mater. Res. Bull. 10, 889 (1975).^*Supported by the USDOE under Contract No. W-7405-Eng-82. Permanent address: Dept. Phys., The Catholic Univ. Korea.

On the self-organization of magnetic field and highly diluted matter in astrophysics

NASA Astrophysics Data System (ADS)

Berdichevsky, D. B.

2015-12-01

It is explored the self organization of matter and field in regions beyond our common reach on the surface of our planet and its atmospheric surroundings. This state of matter, which most basic property, the freezing in the magnetic field, see e.g., Chew et al, 1956, has proved to exist in the regions where robotic observations in the near and far space perform detailed observations of magnetic fields, and extreme dilute plasma (commonly about 1000 to 0.1 or less ionized particles per cubic cm). We present and discuss here simple hypotheses on the nature of what could be this state of magnetized matter which in the electron distribution shows a shape which often can successfully be described with a kappa distribution when inside a strongly magnetized transient, of the magnetic cloud kind, see e.g., Nieves Chinchilla and Figueroa-Viñas, 2008. This work is in many ways an extension of Alfven work on magnetized space plasmas, Alven, 1942. Chew, G.F., M.L., Goldberger, and F.E. Low, 1956, the Royal Soc. London, section Math & Phys Sc., 236, pp. 112. Nieves-Chinchilla, T., and A., Figueroa-Viñas, 2008, J. Geophys. Res., 113, A02105. Alfvén, H (1942). "Existence of electromagnetic-hydrodynamic waves". Nature 150: 405.. doi:10.1038/150405d0

Flux amplification and sustainment of ST plasmas by multi-pulsed coaxial helicity injection on HIST

NASA Astrophysics Data System (ADS)

Higashi, T.; Ishihara, M.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2010-11-01

The Helicity Injected Spherical Torus (HIST) device has been developed towards high-current start up and sustainment by Multi-pulsed Coaxial Helicity Injection (M-CHI) method. Multiple pulses operation of the coaxial plasma gun can build the magnetic field of STs and spheromak plasmas in a stepwise manner. So far, successive gun pulses on SSPX at LLNL were demonstrated to maintain the magnetic field of spheromak in a quasi-steady state against resistive decay [1]. The resistive 3D-MHD numerical simulation [2] for STs reproduced the current amplification by the M-CHI method and confirmed that stochastic magnetic field was reduced during the decay phase. By double pulsed operation on HIST, the plasma current was effectively amplified against the resistive decay. The life time increases up to 10 ms which is longer than that in the single CHI case (4 ms). The edge poloidal fields last between 0.5 ms and 6 ms like a repetitive manner. During the second driven phase, the toroidal ion flow is driven in the same direction as the plasma current as well as in the initial driven phase. At the meeting, we will discuss a current amplification mechanism based on the merging process with the plasmoid injected secondly from the gun. [1] B. Hudson et al., Phys. Plasmas Vol.15, 056112 (2008). [2] Y. Kagei et al., J. Plasma Fusion Res. Vol.79, 217 (2003).

Laser-induced forward transfer for improving fine-line metallization in photovoltaic applications

NASA Astrophysics Data System (ADS)

Sanchez-Aniorte, M. I.; Mouhamadou, B.; Alloncle, A. P.; Sarnet, T.; Delaporte, P.

2016-06-01

Grand challenges to create new front metallization techniques in photovoltaic focus considerable attention on laser-induced forward transfer (LIFT) approach. This alternative method aims to overcome the limitations of the well-established and mature screen-printing (SP) technique. Such limitations are for instance restrictions in the grid pattern design, high-temperature steps, and limited aspect ratio of the line contact (Poulain et al. in Appl Surf Sci 257:5241-5244, 2011). Although different new front contact metallization concepts have been studied, most of them require a second print step to increase the volume of the contact (Gao et al. in Proceedings of 25th EU PVSEC conference, 2010; Beaucarne and Schubert in Energy Proc 67:2-12, 2015; Lossen and Matusovsky in Energy Proc 67:156-162, 2015; Green in Phys E 14:65-70, 2002; Lennon et al. in Prog Photovolt Res Appl V21:1454-1468, 2012). As a result, it is desirable to find innovative metallization techniques to improve the cell efficiency without significantly increasing the cost. Although many challenges remain before to obtain high-quality, robust, and high-performance LIFT contact formation, it required a fully theoretical and experimental assessment. This paper presents the results of a study of the LIFT technique in picosecond regime and thick silver pastes to create high-quality conductive lines for photovoltaic applications.

Complete set of essential parameters of an effective theory

NASA Astrophysics Data System (ADS)

Ioffe, M. V.; Vereshagin, V. V.

2018-04-01

The present paper continues the series [V. V. Vereshagin, True self-energy function and reducibility in effective scalar theories, Phys. Rev. D 89, 125022 (2014); , 10.1103/PhysRevD.89.125022A. Vereshagin and V. Vereshagin, Resultant parameters of effective theory, Phys. Rev. D 69, 025002 (2004); , 10.1103/PhysRevD.69.025002K. Semenov-Tian-Shansky, A. Vereshagin, and V. Vereshagin, S-matrix renormalization in effective theories, Phys. Rev. D 73, 025020 (2006), 10.1103/PhysRevD.73.025020] devoted to the systematic study of effective scattering theories. We consider matrix elements of the effective Lagrangian monomials (in the interaction picture) of arbitrary high dimension D and show that the full set of corresponding coupling constants contains parameters of both kinds: essential and redundant. Since it would be pointless to formulate renormalization prescriptions for redundant parameters, it is necessary to select the full set of the essential ones. This is done in the present paper for the case of the single scalar field.

Resveratrol (trans-3,5,4'-trihydroxystilbene) suppresses EL4 tumor growth by induction of apoptosis involving reciprocal regulation of SIRT1 and NF-κB

PubMed Central

Singh, Narendra P.; Singh, Udai P.; Hegde, Venkatesh L.; Guan, Hongbing; Hofseth, Lorne; Nagarkatti, Mitzi; Nagarkatti, Prakash S.

2012-01-01

Scope Understanding the molecular mechanisms through which natural products and dietary supplements exhibit anticancer properties is crucial and can lead to drug discovery and chemoprevention. The current study sheds new light on the mode of action of Resveratarol (RES), a plant-derived polyphenolic compound, against EL-4 lymphoma growth. Methods and results Immuno-compromised NOD/SCID mice injected with EL-4 tumor cells and treated with RES (100 mg/kg body weight) showed delayed development and progression of tumor growth and increased mean survival time. RES caused apoptosis in EL4 cells through activation of aryl hydrocarbon receptor (AhR) and upregulation of Fas and FasL expression in vitro. Blocking of RES-induced apoptosis in EL4 cells by FasL mAb, cleavage of caspases and PARP, and release of cytochorme c, demonstrated the participation of both extrinsic and intrinsic pathways of apoptosis. RES also induced upregulation of SIRT1 and downregulation of NF-kB in EL4 cells. SiRNA-mediated down regulation of SIRT1 in EL4 cells increased the activation of NF-kB but decreased RES-mediated apoptosis, indicating the critical role of SIRT1 in apoptosis via blocking activation of NF-kB. Conclusion These data suggest that RES-induced SIRT1 upregulation promotes tumor cell apoptosis through negative regulation of NF-kB, leading to suppression of tumor growth. PMID:21520490

Evaluation of free radical scavenging capacity and antioxidative damage effect of resveratrol-nanostructured lipid carriers

NASA Astrophysics Data System (ADS)

Jin, Ju; Shi, Fan; Li, Qiu-wen; Li, Pei-shan; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

2016-03-01

Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical(ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, resveratrol loaded nanostructured lipid carriers (Res-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Res-NLC on free radical scavenging capacity and antioxidative damage is investigated. The particle size and zeta potential of Res-NLC were 139.3 ± 1.7 nm and -11.21 ± 0.41 mV, respectively. By free radical scavenging assays, the IC50 value of Res-NLC were 19.25, 5.29 μg/mL with DPPH, ABTS assay respectively, and 0.161 mg ferrous sulfate/1 mg Res-NLC with FRAP assay; and by AAPH-induced oxidative injury cell model assay, Res-NLC showed the strong protective effect against the human liver tumor HepG2 cell oxidative stress damage. These results indicated that the antioxidant properties of Res-NLC hold great potential used as an alternative to more toxic synthetic antioxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

Energetic Neutral Atom Imaging of the Lunar Poles and Night-Side

NASA Astrophysics Data System (ADS)

Vorburger, Audrey; Wurz, Peter; Barabash, Stas; Wieser, Martin; Futaana, Yoshifumi; Bhardwaj, Anil; Dhanya, Mb; Asamura, Kazushi

2016-04-01

So far all reported scientific results derived from measurements of the Chandrayaan-1 Energetic Neutral Analyzer (CENA) on board the Indian lunar mission Chandrayaan-1 focused on the sun-lit part of the Moon. Here, for the first time, we present the analysis of the Moon - solar wind interaction in Energetic Neutral Atoms (ENAs) from measurements over the poles and the night-side of the Moon. The Moon, not being protected by a global magnetic field or an atmosphere, is constantly bombarded by solar wind ions. Until recently, it was tacitly assumed that the solar wind ions that impinge onto the lunar surface are almost completely absorbed ( < 1% reflection) by the lunar surface (e.g. Crider and Vondrak [Adv. Space Res., 2002]; Feldman et al. [J. Geophys. Res., 2000]). However, recent observations conducted by the two ENA sensors of NASA's Interstellar Boundary Explorer and by Chandrayaan-1/CENA showed an average global energetic neutral atom (ENA) albedo of 10% - 20% (e.g. McComas et al. [Geophys. Res. Lett., 2009], Wieser et al. [Planet. Space Sci., 2009], Vorburger et al. [J. Geophys. Res., 2013]). In the past 6 years, several studies have closely investigated this solar wind - lunar surface interaction from various viewpoints. The main findings of these studies include (1) the dependency of the hydrogen reflection ratio on the local crustal magnetic fields (e.g., Wieser et al. [Geophys. Res. Lett. ,2010] and Vorburger et al. [J. Geophys. Res., 2012]), (2) the determination of the energy spectra of backscattered neutralized solar wind protons (Futaana et al. [J. Geophys. Res., 2012]) (3) the use of the spectra shape to remotely define an electric potential above a lunar magnetic anomaly (Futaana et al. [Geophys. Res. Lett., 2012]), (4) the favouring of backscattering over forward-scattering of impinging solar wind hydrogen particles (Vorburger et al. [Geophys. Res. Lett., 2011]), (5) the first-ever measurements of sputtered lunar oxygen (Vorburger et al. [J. Geophys. Res., 2012]), (6) the first-ever observation of backscattered solar wind helium (Vorburger et al. [J. Geophys. Res., 2012]), and (7) the determination of the scattering properties of backscattered solar wind hydrogen measured when the Moon transversed Earth's magneto-sheath (Lue et al. [J. Geophys. Res., 2016]). All findings above are based on measurements from the sun-lit side of the Moon's surface, where solar wind particles can impinge freely onto the lunar surface. On the night-side, in contrast, a large scale wake structure is formed as a result of the high absorption of solar wind plasma on the lunar day-side. Very recent ion measurements of Chandrayaan-1's Solar Wind Monitor (SWIM) have revealed the presence of protons in the near-lunar wake, though (Dhanya et al., [Icarus 2016 (submitted)]). The presence of protons in the near lunar wake implies that there is also some sort of solar wind - lunar surface interaction on the lunar night-side. A complete analysis of this interaction will be presented herein.

Comment on "Many-body localization in Ising models with random long-range interactions"

NASA Astrophysics Data System (ADS)

Maksymov, Andrii O.; Rahman, Noah; Kapit, Eliot; Burin, Alexander L.

2017-11-01

This Comment is dedicated to the investigation of many-body localization in a quantum Ising model with long-range power-law interactions r-α, relevant for a variety of systems ranging from electrons in Anderson insulators to spin excitations in chains of cold atoms. It has earlier been argued [arXiv:cond-mat/0611387 (2005); Phys. Rev. B 91, 094202 (2015), 10.1103/PhysRevB.91.094202] that this model obeys the dimensional constraint suggesting the delocalization of all finite-temperature states in the thermodynamic limit for α ≤2 d in a d -dimensional system. This expectation conflicts with the recent numerical studies of the specific interacting spin model of Li et al. [Phys. Rev. A 94, 063625 (2016), 10.1103/PhysRevA.94.063625]. To resolve this controversy we reexamine the model of Li et al. [Phys. Rev. A 94, 063625 (2016), 10.1103/PhysRevA.94.063625] and demonstrate that the infinite-temperature states there obey the dimensional constraint. The earlier developed scaling theory for the critical system size required for delocalization is extended to small exponents 0 ≤α ≤d . The disagreements between the two works are explained by the nonstandard selection of investigated states in the ordered phase in the work of Li et al. [Phys. Rev. A 94, 063625 (2016)10.1103/PhysRevA.94.063625].

EDITORIAL: Greetings from the new Editor-in-Chief Greetings from the new Editor-in-Chief

NASA Astrophysics Data System (ADS)

Corkum, Paul

2011-01-01

As a journal that reports advances in atomic, molecular and optical science (AMO), Journal of Physics B: Atomic, Molecular and Optical Physics (J. Phys. B) provides the AMO research community with three unique fora: topical reviews, tutorials and special issues. Developed under the leadership of editor Jan Michael Rost and his Editorial Board, these sections have cemented J. Phys. B's reputation as a major journal showcasing the AMO community's advances. For me, an AMO scientist, it is therefore a special pleasure to be entrusted with continuing the tradition of excellence established by Jan Michael and the Editorial Board. I intend to build on this foundation by ensuring that the journal makes full use of these tools. Topical reviews: a unique focus When J. Phys. B becomes the first journal you turn to for initial reviews about important emerging areas in your field, we as an Editorial Board will have succeeded. To us, a topical review is different from a traditional review—a topical review focuses on emerging sub-fields of AMO physics. Its function is to alert and educate our readers about emerging opportunities. Topical reviews can also serve a closely related function for readers: keeping us up-to-date with critical technologies that lie slightly outside our own fields, such as advances in free-electron lasers science, (which will surely affect our field). Our overall goal is to make your research more productive because of the topical reviews you read within the journal. Tutorials J. Phys. B tutorials are aimed at graduate students or researchers venturing into a new field. Just as in my own research group I encourage all graduate students to write their theses in a way that will be useful to both future graduate students and the larger community beyond my group, J. Phys. B has designed tutorials to fill this function on the journal scale. Thus, tutorial authors are able to write in greater depth than can be included in a paper in nature, science or in the regular pages of J. Phys. B. Often a professor and student will collaborate on a tutorial while the student is writing a thesis. Our challenge as an Editorial Board is to identify the most important topics and most talented authors for such tutorials. Special issues Authors find it uniquely appealing to publish in J. Phys. B special issues, because these issues feature a concentration of papers on a selected topic. This concentration draws attention to all papers in the special issue. However, a special issue never takes over the entire publication, and all J. Phys. B special issue articles are reviewed in the usual way. As an Editorial Board, we will look for emerging sub-fields which have reached a level of maturity that would benefit from a special issue. Suggestions from you, our colleagues As an AMO scientist, I myself am widely informed about my own speciality of attosecond science, but not necessarily up-to-date on emerging advances in other AMO specialities. The Editorial Board and I need your suggestions for special issues, for topical reviews, for tutorials, and for how we can improve J. Phys. B further still. So please email your suggestions, backed by your explanation of why the sub-field is important. Although we cannot guarantee that we will accept all suggestions, I do promise that the Editorial Board will seriously consider every one of them. J. Phys. B's publication process Producing a regular publication is an arduous process. It is the staff who carry out the day-to-day processes on which reliable production depends. They see that your paper is reviewed and published quickly. They are dedicated to serving your specialized needs. The editor's and the Board's role is to serve as a conduit: we help the staff understand the specialized needs of the science community and help the science community to understand the specialized nature of publishing. Looking ahead to my five years as editor, I hope they will be as successful as those of my predecessor, Jan Michael Rost. Jan Michael has steered the journal through the many changes that have occurred in scientific publishing in recent years. While every scientific journal searches for new ways to better-serve its readers, J. Phys. B has developed unique services that can make us scientists more productive. That is the highest accolade I can possibly give to Jan Michael as I begin to build on the strong foundation that he has put in place.

78 FR 59008 - Grant of Interim Extension of the Term of U.S. Patent No. 5,454,779; ResQPump®/ResQPOD® ITD

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-25

... of the application indicates that, except for permission to market or use the product commercially... University of California timely filed an application under 35 U.S.C. 156(d)(5) for a second interim extension... connection with the ResQPOD[supreg] ITD. The application indicates that a Premarket Approval Application, PMA...

Aerobic and Strength Training in Concomitant Metabolic Syndrome and Type 2 Diabetes

PubMed Central

Earnest, Conrad P.; Johannsen, Neil M.; Swift, Damon L.; Gillison, Fiona B.; Mikus, Catherine R.; Lucia, Alejandro; Kramer, Kimberly; Lavie, Carl J.; Church, Timothy S.

2014-01-01

Purpose Concomitant type 2 diabetes (T2D) and metabolic syndrome exacerbates mortality risk; yet, few studies have examined the effect of combining (AER+RES) aerobic (AER) and resistance (RES) training for individuals with T2D and metabolic syndrome. Methods We examined AER, RES, and AER+RES training (9-months) commensurate with physical activity guidelines in individuals with T2D (N=262, 63% female, 44% black). Primary outcomes were change in, and prevalence of, metabolic syndrome score at follow-up (mean, 95%CI). Secondary outcomes included maximal cardiorespiratory fitness (VO2peak and estimated METs from time-to-exhaustion (TTE), and exercise efficiency calculated as the slope of the line between ventilatory threshold, respiratory compensation, and maximal fitness. General linear models and bootstrapped Spearman correlations were used to examine changes in metabolic syndrome associated with training primary and secondary outcome variables. Results We observed a significant decrease in metabolic syndrome scores (P-for-trend, 0.003) for AER (−0.59, 95%CI, −1.00, −0.21) and AER+RES (−0.79, 95%CI, −1.40, −0.35), both being significant (P < 0.02) vs. Control (0.26, 95%CI, −0.58, 0.40) and RES (−0.13, 95%CI, −1.00, 0.24). This lead to a reduction in metabolic syndrome prevalence for the AER (56% vs. 43%) and AER+RES (55% vs. 46%) groups between baseline and follow-up. The observed decrease in metabolic syndrome was mediated by significant improvements in exercise efficiency for the AER and AER+RES training groups (P<0.05), which was more strongly related to TTE (25–30%; r= −0.38; 95% CI: −0.55, −0.19) than VO2peak (5–6%; r= −0.24; 95% CI: −0.45, −0.01). Conclusion Aerobic and AER+RES training significantly improves metabolic syndrome scores and prevalence in patients with T2D. These improvements appear to be associated with improved exercise efficiency and are more strongly related to improved TTE versus VO2peak. PMID:24389523

Globalisation and science education: the case of Sustainability by the Bay

NASA Astrophysics Data System (ADS)

Carter, Lyn; Dediwalage, Ranjith

2010-06-01

It is impossible to consider contemporary science education in isolation from globalisation as the dominant logic, rethinking and reconfiguring social and cultural life in which it is located. Carter (J Res Sci Teach 42, 561-580, 2005) calls for a close reading of policy documents, curriculum projects, research studies and a range of other science education texts using key concepts from globalisation theory to elucidate the ways in which globalisation shapes and is expressed within science education. In this paper, we consider an example from our own practice of a school-based curriculum project, Sustainable Living by the Bay, as one such instance. The first section reviews neoliberalism and neoconservativism necessary to understand how globalisation penetrates education, while the second outlines aspects of the curriculum project itself. As there were many different facets to the development and implementation of a project like Sustainable Living by the Bay, there is space only to elaborate two examples of the globalisation discourse. The first example concerns the government policy initiative that funded the project while the second example focuses on learner- centred pedagogies as globalisation's pedagogies of choice.

Direct Methanol Fuel Cell Battery Replacement Program

DTIC Science & Technology

2011-04-11

Matthey PtRu in operating direct methanol fuel cells” Phys. Chem. Chem. Phys., 10, 6430-6437 (2008) 2. Harry Rivera, Jamie S. Lawton , David E. Budil and...Phys. Chem. B, 112, (29) 8542-8548 (2008) 3. Jamie S. Lawton , Eugene S. Smotkin and David E. Budil, “ESR Investigation of Microviscosity, Microscopic

Effects of nutritional plane and selenium supply during gestation on visceral organ mass and indices of intestinal growth and vascularity in primiparous ewes at parturition and during early lactation.

PubMed

Meyer, A M; Reed, J J; Neville, T L; Taylor, J B; Reynolds, L P; Redmer, D A; Vonnahme, K A; Caton, J S

2012-08-01

Objectives were to investigate effects of nutritional plane and Se supply during gestation on visceral organ mass and intestinal growth and vascularization in ewes at parturition and during early lactation. Primiparous Rambouillet ewes (n = 84) were allocated to 2 × 3 × 2 factorial arrangement of treatments. Factors included dietary Se [adequate Se (ASe, 11.5 μg/kg BW) or high Se (HSe, 77.0 μg/kg BW)], nutritional plane [60% (restricted; RES), 100% (control; CON), or 140% (high; HIH)], and physiological stage at necropsy (parturition or d 20 of lactation). At parturition, lambs were removed and 42 ewes (7 per treatment) were necropsied. Remaining ewes were transitioned to a common diet which met lactation requirements and mechanically milked for 20 d. In the absence of interactions (P > 0.10), main effects are reported. At parturition, stomach complex and liver masses were greatest for HIH, intermediate for CON, and least for RES (P < 0.02). Small intestinal mass was greater (P ≤ 0.002) for HIH than RES and CON, and greater (P < 0.01) for ASe than HSe. During early lactation, RES and CON gastrointestinal masses increased disproportionally to BW (P < 0.05). At parturition, jejunal mucosal density was less (P ≤ 0.01) for RES than CON and HIH, whereas CON had greater (P < 0.003) jejunal mucosal RNA concentration and RNA:DNA than RES and HIH. Although there were no differences (P > 0.17) at parturition, jejunal cell percent proliferation was greatest in RES, intermediate in CON, and least in HIH (P ≤ 0.09) at d 20 lactation. At both stages, RES had less (P = 0.01) jejunal capillary area density than HIH and less (P ≤ 0.03) capillary surface density than CON and HIH. During lactation, jejunal capillary size was greater (P = 0.04) for ewes previously fed HSe compared with ASe. At parturition, ASe-HIH had greater (P < 0.02) jejunal mucosal endothelial nitric oxide synthase 3 mRNA than all other treatments and greater (P = 0.10) vascular endothelial growth factor (VEGF) than all treatments, except ASe-RES. In addition, CON had less (P ≤ 0.08) jejunal VEGF receptor-1 (FLT1) mRNA compared with RES and HIH, and ASe had greater (P = 0.003) FLT1 than HSe at parturition. Ewes fed HIH had greater (P = 0.04) jejunal VEGF receptor-2 mRNA compared with RES. Results indicate that maternal intestinal growth and vascularization are responsive to nutritional plane and dietary Se during gestation and undergo changes postpartum when under similar lactational management.

Pulsed Photolytic Density Scaling Experiment for BiF

DTIC Science & Technology

1989-05-01

on Lasers 86, ed. W. B. Lacina, Soc. for Opt. and Quantum Electronics, STS Press. 281 (1987). 9a. R. F. Heidner, H . Helvajian , J. S. Holloway, and J. B...Koffend, J. Chem. Phys. 84, 2137 (1986). 9b. H . Helvajian , J. S. Holloway, and J. B. Koffend, J. Chem. Phys. (in press). 10. J. B. Koffend and R. F...C. E. Gardner, and R. F. Heidner, J. Chem. Phys. 83, 2904 (1985). 13. R. F. Heidner, H . Helvajian , and J. B. Koffend, J. Chem. Phys. 87, 520 (1987

Reactive Removal of BiF Ground State

DTIC Science & Technology

1990-09-28

1978). 3. W E. Jones and T D. McLean, J. Mol. Spectrosc. 90, 481 (1981). 4. R. E Heidner, H . Helvajian , J. S. Holloway, and J. B. Koffend, J. Chem...Phys. 84, 2137 (1986). 5. C. R. Jones and H . P. Broida, J. Chem. Phys. 60, 4369 (1974). 6. H . Helvajian , J. S. Holloway, and J. B. Koffend, J. Chem...Phys. Rev. A6, 631 (1972). 27. H . Hotop and W C. Lineberger, J. Phys. Chem. Ref. Data 4, 539 (1985). 28. J.M. Herbelin, Conf. Proc., Intl. Gonf. on

Heats of Vaporization of Room Temperature Ionic Liquids by Tunable Vacuum Ultraviolet Photoionization

DTIC Science & Technology

2009-12-07

18) Emel’yanenko, V. N.; Verevkin, S. P.; Heintz, A.; Corfield, J.-A.; deyko, A.; Lovelock , K. R. J.; Licence, P.; Jones, R. G. J. Phys. Chem. B 2008...112, 11734. (19) Armstrong, J. P.; Hurst, C.; Jones, R. G.; Licence, P.; Lovelock , K. R. J.; Satterly, C. J.; Villar-Garcia, I. J. Phys. Chem. Chem...Phys. 2007, 9, 982. (20) Lovelock , K. R. J.; Deyko, A.; Corfield, J.-A.; Gooden, P. N.; Licence, P.; Jones, R. G. ChemPhysChem 2009, 10, 337. (21

Electrostatic Plugging of Multidipole Cusps.

DTIC Science & Technology

1982-05-01

8217, -) V0 100 I-’ 60 00 0> :oc 0 \\0H U 0 0- 0- -L 0 0- P4 A- 602- 179 MASS SPECTROMETER CIRCUIT CHME P OGA- SWOT Figue 1. Shemaic f eteralXly...2R. L. Hirsch, J. Appl . Phys. 38, 4522 (1967). 3N. Hershkowitz K. N. Leung, and T. Romesser, Phys. Rev. Lett. 5. 277 (1975 1. 4A. Kitsunezaki, M...R. T. Carpenter, submitted to J. Appl . Phys. 1OD. Rapp and P. Englander-Golden, J. Chem. Phys. 3, 1464 (1965). "A. Lang and N. Hershkowitz, J. Appl

Upper bound on three-tangles of reduced states of four-qubit pure states

NASA Astrophysics Data System (ADS)

Sharma, S. Shelly; Sharma, N. K.

2017-06-01

Closed formulas for upper bounds on three-tangles of three-qubit reduced states in terms of three-qubit-invariant polynomials of pure four-qubit states are obtained. Our results offer tighter constraints on total three-way entanglement of a given qubit with the rest of the system than those used by Regula et al. [Phys. Rev. Lett. 113, 110501 (2014), 10.1103/PhysRevLett.113.110501 and Phys. Rev. Lett. 116, 049902(E) (2016)], 10.1103/PhysRevLett.116.049902 to verify monogamy of four-qubit quantum entanglement.

B80 and B101-103 clusters: Remarkable stability of the core-shell structures established by validated density functionalsa)

NASA Astrophysics Data System (ADS)

Li, Fengyu; Jin, Peng; Jiang, De-en; Wang, Lu; Zhang, Shengbai B.; Zhao, Jijun; Chen, Zhongfang

2012-02-01

Prompted by the very recent claim that the volleyball-shaped B80 fullerene [X. Wang, Phys. Rev. B 82, 153409 (2010), 10.1103/PhysRevB.82.153409] is lower in energy than the B80 buckyball [N. G. Szwacki, A. Sadrzadeh, and B. I. Yakobson, Phys. Rev. Lett. 98, 166804 (2007), 10.1103/PhysRevLett.98.166804] and core-shell structure [J. Zhao, L. Wang, F. Li, and Z. Chen, J. Phys. Chem. A 114, 9969 (2010), 10.1021/jp1018873], and inspired by the most recent finding of another core-shell isomer as the lowest energy B80 isomer [S. De, A. Willand, M. Amsler, P. Pochet, L. Genovese, and S. Goedecher, Phys. Rev. Lett. 106, 225502 (2011), 10.1103/PhysRevLett.106.225502], we carefully evaluated the performance of the density functional methods in the energetics of boron clusters and confirmed that the core-shell construction (stuffed fullerene) is thermodynamically the most favorable structural pattern for B80. Our global minimum search showed that both B101 and B103 also prefer a core-shell structure and that B103 can reach the complete core-shell configuration. We called for great attention to the theoretical community when using density functionals to investigate boron-related nanomaterials.

Binding energy of e^+Li using the Peach model potential.

NASA Astrophysics Data System (ADS)

Shertzer, Janine; Ward, Sandra

2006-05-01

The l-independent, parametric model potential developed by Peach^1 for describing the electron interaction with the alkali ion core yields energy levels that are in excellent agreement with experiment. Because of its relative simplicity, this model potential is an attractive choice for studying e^+- Li collisions;^2,3 the e^+-ion core interaction is obtained by changing the sign of the static term in the interaction. In order to test the usefulness of the potential for describing the physics of an effective three-body system, we calculated the binding energy of e^+Li. This is a stringent test, because the system is very weakly bound. Our results are in excellent agreement with previous calculations,^4 including those using the exact four-body Hamiltonian.^5 This work was funded by NSF under collaborative Grant PHYS-0440714 (JS) and PHYS-0440565 (SJW). ^1G. Peach, H.E. Saraph and M.J. Seaton, J. Phys. B 21, 3669 (1988). ^2M.S.T. Watts and J.W. Humberston, J. Phys. B 25, L491 (1992). ^3S. J. Ward and J. Shertzer, Phys. Rev. A 68, 032720 (2003). ^4J. Mitroy, M.W.J. Bromley, and G.G. Ryzhikh, J. Phys. B 35, R81 (2002). ^5Massimo Mella, Gabriele Morosi, and Dario Bressanini, J. Chem. Phys. 111, 108 (1999).

Adaptive clustering procedure for continuous gravitational wave searches

NASA Astrophysics Data System (ADS)

Singh, Avneet; Papa, Maria Alessandra; Eggenstein, Heinz-Bernd; Walsh, Sinéad

2017-10-01

In hierarchical searches for continuous gravitational waves, clustering of candidates is an important post-processing step because it reduces the number of noise candidates that are followed up at successive stages [J. Aasi et al., Phys. Rev. Lett. 88, 102002 (2013), 10.1103/PhysRevD.88.102002; B. Behnke, M. A. Papa, and R. Prix, Phys. Rev. D 91, 064007 (2015), 10.1103/PhysRevD.91.064007; M. A. Papa et al., Phys. Rev. D 94, 122006 (2016), 10.1103/PhysRevD.94.122006]. Previous clustering procedures bundled together nearby candidates ascribing them to the same root cause (be it a signal or a disturbance), based on a predefined cluster volume. In this paper, we present a procedure that adapts the cluster volume to the data itself and checks for consistency of such volume with what is expected from a signal. This significantly improves the noise rejection capabilities at fixed detection threshold, and at fixed computing resources for the follow-up stages, this results in an overall more sensitive search. This new procedure was employed in the first Einstein@Home search on data from the first science run of the advanced LIGO detectors (O1) [LIGO Scientific Collaboration and Virgo Collaboration, arXiv:1707.02669 [Phys. Rev. D (to be published)

Study of Various Types of Resonances within the Phonon Damping Model

NASA Astrophysics Data System (ADS)

Dang, Nguyen Dinh

2001-10-01

The main successes of the Phonon Damping Model (PDM)(N. Dinh Dang and A. Arima, Phys. Rev. Lett. 80), 4145 (1998); Nucl. Phys. A 636, 427 (1998); N. Dinh Dang, K. Tanabe, and A. Arima, Phys. Rev. C 58, 3374 (1998). are presented in the description of: 1) the giant dipole resonance (GDR) in highly excited nuclei, 2) the double giant dipole resonance (DGDR) and multiple phonon resonances, 3) the Gamow-Teller resonance (GTR), and 4) the damping of pygmy dipole resonance (PDR) in neutron-rich nuclei. The analyses of results of numerical calculations are discussed in comparison with the experimental systematics on i) the width and the shape of the GDR at finite temperature ^1,(N. Dinh Dang et al., Phys. Rev. C 61), 027302 (2000). and angular momentum(N. Dinh Dang, Nucl. Phys. A 687), 261c (2001). for tin isotopes , ii) the electromagnetic cross sections of DGDR for ^136Xe and ^208Pb on a lead target at relativistic energies(N. Dinh Dang, V. Kim Au, and A. Arima, Phys. Rev. Lett. 85), 1827 (2000)., iii) the strength function of GTR(N. Dinh Dang, T. Suzuki, and A. Arima, Preprint RIKEN-AF-NF 377 (2000), submitted.), and iv) the PDR in oxygen and calcium isotopes(N. Dinh Dang et al., Phys. Rev. C 63), 044302 (2001)..

Precision measurements with atom interferometry

NASA Astrophysics Data System (ADS)

Schubert, Christian; Abend, Sven; Schlippert, Dennis; Ertmer, Wolfgang; Rasel, Ernst M.

2017-04-01

Interferometry with matter waves enables precise measurements of rotations, accelerations, and differential accelerations [1-5]. This is exploited for determining fundamental constants [2], in fundamental science as e.g. testing the universality of free fall [3], and is applied for gravimetry [4], and gravity gradiometry [2,5]. At the Institut für Quantenoptik in Hannover, different approaches are pursued. A large scale device is designed and currently being set up to investigate the gain in precision for gravimetry, gradiometry, and fundamental tests on large baselines [6]. For field applications, a compact and transportable device is being developed. Its key feature is an atom chip source providing a collimated high flux of atoms which is expected to mitigate systematic uncertainties [7,8]. The atom chip technology and miniaturization benefits from microgravity experiments in the drop tower in Bremen and sounding rocket experiments [8,9] which act as pathfinders for space borne operation [10]. This contribution will report about our recent results. The presented work is supported by the CRC 1227 DQ-mat, the CRC 1128 geo-Q, the RTG 1729, the QUEST-LFS, and by the German Space Agency (DLR) with funds provided by the Federal Ministry of Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grant No. DLR 50WM1552-1557. [1] P. Berg et al., Phys. Rev. Lett., 114, 063002, 2015; I. Dutta et al., Phys. Rev. Lett., 116, 183003, 2016. [2] J. B. Fixler et al., Science 315, 74 (2007); G. Rosi et al., Nature 510, 518, 2014. [3] D. Schlippert et al., Phys. Rev. Lett., 112, 203002, 2014. [4] A. Peters et al., Nature 400, 849, 1999; A. Louchet-Chauvet et al., New J. Phys. 13, 065026, 2011; C. Freier et al., J. of Phys.: Conf. Series 723, 012050, 2016. [5] J. M. McGuirk et al., Phys. Rev. A 65, 033608, 2002; P. Asenbaum et al., arXiv:1610.03832. [6] J. Hartwig et al., New J. Phys. 17, 035011, 2015. [7] H. Ahlers et al., Phys. Rev. Lett. 116, 173601, 2016; S. Abend et al., Phys. Rev. Lett. 117, 203003, 2016. [8] J. Rudolph et al., New J. Phys. 17, 065001, 2015. [9] H. Müntinga et al., Phys. Rev. Lett., 110, 093602, 2013. [10] O. Carraz et al., Microgravity Sci. Technol. 26, 139, 2014; D. Aguilera et al., Class. Quantum Grav. 31, 115010, 2014.

Dirac Magnons in Honeycomb Ferromagnets

NASA Astrophysics Data System (ADS)

Pershoguba, Sergey S.; Banerjee, Saikat; Lashley, J. C.; Park, Jihwey; Ågren, Hans; Aeppli, Gabriel; Balatsky, Alexander V.

2018-01-01

The discovery of the Dirac electron dispersion in graphene [A. H. Castro Neto, et al., The Electronic Properties of Graphene, Rev. Mod. Phys. 81, 109 (2009), 10.1103/RevModPhys.81.109] led to the question of the Dirac cone stability with respect to interactions. Coulomb interactions between electrons were shown to induce a logarithmic renormalization of the Dirac dispersion. With a rapid expansion of the list of compounds and quasiparticle bands with linear band touching [T. O. Wehling, et al., Dirac Materials, Adv. Phys. 63, 1 (2014), 10.1080/00018732.2014.927109], the concept of bosonic Dirac materials has emerged. We consider a specific case of ferromagnets consisting of van der Waals-bonded stacks of honeycomb layers, e.g., chromium trihalides CrX3 (X =F , Cl, Br and I), that display two spin wave modes with energy dispersion similar to that for the electrons in graphene. At the single-particle level, these materials resemble their fermionic counterparts. However, how different particle statistics and interactions affect the stability of Dirac cones has yet to be determined. To address the role of interacting Dirac magnons, we expand the theory of ferromagnets beyond the standard Dyson theory [F. J. Dyson, General Theory of Spin-Wave Interactions, Phys. Rev. 102, 1217 (1956), 10.1103/PhysRev.102.1217, F. J. Dyson, Thermodynamic Behavior of an Ideal Ferromagnet, Phys. Rev. 102, 1230 (1956), 10.1103/PhysRev.102.1230] to the case of non-Bravais honeycomb layers. We demonstrate that magnon-magnon interactions lead to a significant momentum-dependent renormalization of the bare band structure in addition to strongly momentum-dependent magnon lifetimes. We show that our theory qualitatively accounts for hitherto unexplained anomalies in nearly half-century-old magnetic neutron-scattering data for CrBr3 [W. B. Yelon and R. Silberglitt, Renormalization of Large-Wave-Vector Magnons in Ferromagnetic CrBr3 Studied by Inelastic Neutron Scattering: Spin-Wave Correlation Effects, Phys. Rev. B 4, 2280 (1971), 10.1103/PhysRevB.4.2280, E. J. Samuelsen, et al., Spin Waves in Ferromagnetic CrBr3 Studied by Inelastic Neutron Scattering, Phys. Rev. B 3, 157 (1971), 10.1103/PhysRevB.3.157]. We also show that honeycomb ferromagnets display dispersive surface and edge states, unlike their electronic analogs.

Industrial solutions trends for the control of HiRes spectrograph@E-ELT

NASA Astrophysics Data System (ADS)

Di Marcantonio, P.; Baldini, V.; Calderone, G.; Cirami, R.; Coretti, I.; Cristiani, S.

Starting a few years ago, ESO initiated a number of projects aiming to explore the possible adoption of industrial standards and commercial off-the-shelf components (COTS) for the control of future VLT and E-ELT instrumentations. In this context, ESPRESSO, the next generation high-stability spectrograph for the VLT and to a certain extent, a precursor of HiRes, has adopted since the preliminary design phase those solutions. Based on the ESPRESSO experience and taking into account the requirements inferred from the preliminary Hi-Res studies in terms of both high-level operations as well as low-level control, I will present in this paper the current proposal for the HiRes hardware architecture.

Interagency Training for Comprehensive Operations: Government Partners Perceptions of Exercise Maple Guardian (La Formation Interorganismes aux fins d’Operations Globales: Perceptions des Partenaires Gouvernementaux de l’Exercise Maple Guardian)

DTIC Science & Technology

2010-06-01

autres ministères de même que sur la culture afghane, et faire intervenir les autres ministères plus tôt durant la planification de l’exercice...mécanismes de planification des FC. Ils jugent que la formation les a aidés à établir des relations utiles avec des membres des FC (et d’autres effectifs...ministères et sur la culture afghane, et de faire intervenir d’autres ministères plus tôt durant la planification de l’exercice. Les résultats de

Probing the Hydrogen Sublattice of FeHx with High-Pressure Neutron Diffraction

NASA Astrophysics Data System (ADS)

Murphy, C. A.; Guthrie, M.; Boehler, R.; Somayazulu, M.; Fei, Y.; Molaison, J.; dos Santos, A. M.

2013-12-01

The combination of seismic, cosmochemical, and mineral physics observations have revealed that Earth's iron-rich core must contain some light elements, such as hydrogen, carbon, oxygen, silicon, and/or sulfur. Therefore, understanding the influence of these light elements on the structural, thermoelastic, and electronic properties of iron is important for constraining the composition of this remote layer of the Earth and, in turn, providing constraints on planetary differentiation and core formation models. The high-pressure structural and magnetic properties of iron hydride (FeHx) have previously been studied using synchrotron x-ray diffraction and Mössbauer spectroscopy. Such experiments revealed that the double hexagonal close-packed (dhcp) structure of FeHx is stable above a pressure of ~5 GPa and up to at least 80 GPa at 300 K [1]. In addition, dhcp-FeHx is ferromagnetic at low-pressures, but undergoes a magnetic collapse around 22 GPa [2]. X-ray experiments provide valuable insight into the properties of FeHx, but such techniques are largely sensitive to the iron component because it is difficult to detect the hydrogen sublattice with x-rays. Therefore, neutron diffraction has been used to investigate metastable FeHx, which is formed by quenching the high-pressure phase to liquid nitrogen temperatures and probing the sample at ambient pressure [3]. However, such neutron experiments have been limited to formation pressures below 10 GPa, and cannot be performed at ambient temperature. Here we present the first in-situ investigation of FeHx at 300 K using high-pressure neutron diffraction experiments performed at the Spallation Neutrons and Pressure Diffractometer (SNAP) instrument at the Spallation Neutron Source, Oak Ridge National Laboratory. In order to achieve pressures of ~50 GPa, we loaded iron samples with a hydrogen gas pressure medium into newly designed large-volume panoramic diamond-anvil cells (DACs) for neutron diffraction experiments [4; 5]. We will present the details of our DAC preparations and results of our in-situ structural refinements of dhcp-FeHx up to ~50 GPa. Together with previous investigations of the thermoelastic and electronic properties of FeHx [2; 6], we will discuss implications for the composition of Earth's iron-rich core. References: 1. N. Hirao et al. (2004), Geophys. Res. Lett., 31, L06616, doi:10.1029/2003GL019380. 2. W.L. Mao et al. (2004), Geophys. Res. Lett., 31, L15618, doi:10.1029/2004GL020541. 3. V.E. Antonov et al. (2002), J. Phys.: Condens. Matter, 14, 6427-6445, doi:10.1088/0953-8984/14/25/311. 4. M. Guthrie et al. (2013), ACA Transactions, 44, in press. 5. R. Boehler et al. (2013), High Press. Res., in press, doi:10.1080/08957959.2013.823197. 6. Y. Shibazaki et al. (2012), Earth Planet. Sci. Lett., 313-314, 79-85, doi:10.1016/j.epsl.2011.11.002.

Paradoxical effects of testing: retrieval enhances both accurate recall and suggestibility in eyewitnesses.

PubMed

Chan, Jason C K; Langley, Moses M

2011-01-01

Although retrieval practice typically enhances memory retention, it can also impair subsequent eyewitness memory accuracy (Chan, Thomas, & Bulevich, 2009). Specifically, participants who had taken an initial test about a witnessed event were more likely than nontested participants to recall subsequently encountered misinformation—an effect we called retrieval-enhanced suggestibility (RES). Here, we sought to test the generality of RES and to further elucidate its underlying mechanisms. To that end, we tested a dual mechanism account, which suggests that RES occurs because initial testing (a) enhances learning of the later misinformation by reducing proactive interference and (b) causes the reactivated memory trace to be more susceptible to later interference (i.e., a reconsolidation account). Three major findings emerged. First, RES was found after a 1-week delay, where a robust testing benefit occurred for event details that were not contradicted by later misinformation. Second, blockage of reconsolidation was unnecessary for RES to occur. Third, initial testing enhanced learning of the misinformation even when proactive interference played a minimal role.

Electronic and optoelectronic device applications based on ReS2

NASA Astrophysics Data System (ADS)

Liu, Erfu; Long, Mingsheng; Wang, Yaojia; Pan, Yiming; Ho, Chinghwa; Wang, Baigeng; Miao, Feng

Rhenium disulfide (ReS2) is a unique semiconducting TMD with distorted 1T structure and weak interlayer coupling. We have previously investigated its in-plane anisotropic property and electronic applications on FET and digital inverters. In this talk, we will present high responsivity phototransistors based on few-layer ReS2. Depending on the back gate voltage, source drain bias and incident optical light intensity, the maximum attainable photoresponsivity can reach as high as 88,600 A W-1, which is one of the highest value among individual two-dimensional materials with similar device structures. Such high photoresponsivity is attributed to the increased light absorption as well as the gain enhancement due to the existence of trap states in the few-layer ReS2 flakes. The existence of trap states is proved by temperature dependent transport measurements. It further enables the detection of weak signals. Our studies underscore ReS2 as a promising material for future electronic and sensitive optoelectronic applications.

Will Renewable Energy Save Our Planet?

NASA Astrophysics Data System (ADS)

Bojić, Milorad

2010-06-01

This paper discusses some important fundamental issues behind application of renewable energy (RE) to evaluate its impact as a climate change mitigation technology. The discussed issues are the following: definition of renewable energy, concentration of RE by weight and volume, generation of electrical energy and its power at unit area, electrical energy demand per unit area, life time approach vs. layman approach, energy return time, energy return ratio, CO2 return time, energy mix for RES production and use, geographical distribution of RES use, huge scale of energy shift from RES to non-RES, increase in energy consumption, Thermodynamic equilibrium of earth, and probable solutions for energy future of our energy and environmental crisis of today. The future solution (that would enable to human civilization further welfare, and good living, but with lower release of CO2 in atmosphere) may not be only RES. This will rather be an energy mix that may contain nuclear energy, non-nuclear renewable energy, or fossil energy with CO2 sequestration, efficient energy technologies, energy saving, and energy consumption decrease.

Numerical investigations of solute transport in bimodal porous media under dynamic boundary conditions

NASA Astrophysics Data System (ADS)

Cremer, Clemens; Neuweiler, Insa; Bechtold, Michel; Vanderborght, Jan

2016-04-01

Quantification of flow and solute transport in the shallow subsurface adjacent to the atmosphere is decisive to prevent groundwater pollution and conserve groundwater quality, to develop successful remediation strategies and to understand nutrient cycling. In nature, due to erratic precipitation-evaporation patterns, soil moisture content and related hydraulic conductivity in the vadose zone are not only variable in space but also in time. Flow directions and flow paths locally change between precipitation and evaporation periods. This makes the identification and description of solute transport processes in the vadose zone a complex problem. Recent studies (Lehmann and Or, 2009; Bechtold et al., 2011a) focused on the investigation of upward transport of solutes during evaporation in heterogeneous soil columns, where heterogeneity was introduced by a sharp vertical material interface between two types of sand. Lateral solute transport through the interface in both (lateral) directions was observed at different depths of the investigated soil columns. Following recent approaches, we conduct two-dimensional numerical simulations in a similar setup which is composed of two sands with a sharp vertical material interface. The investigation is broadened from the sole evaporation to combined precipitation-evaporation cycles in order to quantify transport processes resulting from the combined effects of heterogeneous soil structure and dynamic flow conditions. Simulations are performed with a coupled finite volume and random walk particle tracking algorithm (Ippisch et al., 2006; Bechtold et al., 2011b). By comparing scenarios with cyclic boundary conditions and stationary counterparts with the same net flow rate, we found that duration and intensity of precipitation and evaporation periods potentially have an influence on lateral redistribution of solutes and thus leaching rates. Whether or not dynamic boundary conditions lead to significant deviations in the transport behavior depends on the magnitude of the flow rates and hydraulic conductivity curves of the materials. Based on the unsaturated hydraulic conductivity at the intersection point of conductivity curves, we are able to define an estimate of flow rates at which the dynamic of the upper boundary condition significantly alters preferential flow paths through the system. If flow rates are low, with regard to the materials hydraulic conductivity at the intersection point, the influence of dynamic boundary conditions is small. If flow rates are in the range of the unsaturated hydraulic conductivity at intersection, solute is trapped in the fine material during upwards transport, which results in a more pronounced tailing. For flow rates exceeding the intersection conductivity, a redistribution at the soil surface can occur. References: Bechtold, M., S. Haber-Pohlmeier, J. Vanderborght, A. Pohlmeier, T.P.A. Ferré and H. Veerecken. 2011a. Near-surface solute redistribution during evaporation. Geophys. Res. Lett., 38, L17404, doi:10.1029/2011GL048147. Bechtold, M., J. Vanderborght, O. Ippisch and H. Vereecken. 2011b. Efficient random walk particle tracking algorithm for advective dispersive transport in media with discontinuous dispersion coefficients and water contents. Water Resour. Res., 47, W10526, doi: 10.1029/2010WR010267. Ippisch O., H.-J. Vogel and P. Bastian. 2006. Validity limits fort he van Genuchten-Mualem model and implications for parameter estimation and numerical simulation. Adv. Water Resour., 29, 1780-1789, doi: 10.1016/j.advwateres.2005.12.011. Lehmann, P. and D. Or. 2009. Evaporation and capillary coupling across vertical textural contrasts in porous media. Phys. Rev. E, 80, 046318, doi:10.1103/PhysRevE.80.046318.