1,607 research outputs found
Magnetic and transport properties of i--Cd icosahedral quasicrystals ( = Y, Gd-Tm)
We present a detailed characterization of the recently discovered i--Cd
( = Y, Gd-Tm) binary quasicrystals by means of x-ray diffraction,
temperature-dependent dc and ac magnetization, temperature-dependent resistance
and temperature-dependent specific heat measurements. Structurally, the
broadening of x-ray diffraction peaks found for i--Cd is dominated by
frozen-in phason strain, which is essentially independent of . i-Y-Cd is
weakly diamagnetic and manifests a temperature-independent susceptibility.
i-Gd-Cd can be characterized as a spin-glass below 4.6 K via dc magnetization
cusp, a third order non-linear magnetic susceptibility peak, a
frequency-dependent freezing temperature and a broad maximum in the specific
heat. i--Cd ( = Ho-Tm) is similar to i-Gd-Cd in terms of features
observed in thermodynamic measurements. i-Tb-Cd and i-Dy-Cd do not show a clear
cusp in their zero-field-cooled dc magnetization data, but instead show a more
rounded, broad local maximum. The resistivity for i--Cd is of order 300 cm and weakly temperature-dependent. The characteristic freezing
temperatures for i--Cd ( = Gd-Tm) deviate from the de Gennes scaling, in
a manner consistent with crystal electric field splitting induced local moment
anisotropy.Comment: 14 page
Palynofacies classification of the depositional elements of confined turbidite systems : Examples from the Gres d'Annot, SE France
Acknowledgements We thank BG Brasil for financial support for this project and permission to publish. BG Group is a wholly owned subsidiary of Royal Dutch Shell. McArthur is grateful to the Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES) for the scholarship 049/2012. The AgĂȘncia Nacional do PetrĂłleo (ANP) are thanked for supporting this project. Massimo Zecchin is thanked for handling this paper and Roberto Tinterri is thanked for his constructive review, in addition to an anonymous reviewer.Peer reviewedPostprin
Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
Radial velocity measurements of stellar reflex motion have revealed many
extrasolar planets, but gaps in the observations produce aliases, spurious
frequencies that are frequently confused with the planets' orbital frequencies.
In the case of Gl 581 d, the distinction between an alias and the true
frequency was the distinction between a frozen, dead planet and a planet
possibly hospitable to life (Udry et al. 2007; Mayor et al. 2009). To improve
the characterization of planetary systems, we describe how aliases originate
and present a new approach for distinguishing between orbital frequencies and
their aliases. Our approach harnesses features in the spectral window function
to compare the amplitude and phase of predicted aliases with peaks present in
the data. We apply it to confirm prior alias distinctions for the planets GJ
876 d and HD 75898 b. We find that the true periods of Gl 581 d and HD 73526
b/c remain ambiguous. We revise the periods of HD 156668 b and 55 Cnc e, which
were afflicted by daily aliases. For HD 156668 b, the correct period is 1.2699
days and minimum mass is (3.1 +/- 0.4) Earth masses. For 55 Cnc e, the correct
period is 0.7365 days -- the shortest of any known planet -- and minimum mass
is (8.3 +/- 0.3) Earth masses. This revision produces a significantly improved
5-planet Keplerian fit for 55 Cnc, and a self-consistent dynamical fit
describes the data just as well. As radial velocity techniques push to
ever-smaller planets, often found in systems of multiple planets,
distinguishing true periods from aliases will become increasingly important.Comment: Accepted by ApJ (in press); 19 pages, 22 figures. Fixed typos;
improved wording; added more extensive discussion of orbital eccentricity;
improved figure captions; additional reference
SPEAM-II experiment for the measurement of stratospheric NO2, O3 and aerosols
Following the success of the Sunphotometer Earth Atmosphere Measurement (SPEAM-I) experiment, a more involved experiment was developed to fly as part of the second set of Canadian Experiments (CANEX-2) which will fly on the US Space Shuttle in the fall of 1992. The instrument complement includes an IBM-PC compatible control computer, a hand-held diode array spectrophotometer, and an interference-filter, limb imaging radiometer for the measurement of the atmospheric airglow. The hand-held spectrometer will measure nitrogen dioxide, ozone and aerosols. The limb imaging radiometer will observe emissions from the O2(1 DELTA) and O2(1 SIGMA) airglow bands. Only the spectrophotometer will be discussed here
Darboux Transformations for Supersymmetric Korteweg - de Vries Equations
\hspace{.2in}We consider the Darboux type transformations for the spectral
problems of supersymmetric KdV systems. The supersymmetric analogies of Darboux
and Darboux-Levi transformations are established for the spectral problems of
Manin-Radul-Mathieu sKdV and Manin-Radul sKdV. Several B\"acklund
transformations are derived for the MRM sKdV and MR sKdV systems.Comment: Latex, 8 pages AS-ITP-94-4
Effective Average Action in N=1 Super-Yang-Mills Theory
For N=1 Super-Yang-Mills theory we generalize the effective average action
Gamma_k in a manifest supersymmetric way using the superspace formalism. The
exact evolution equation for Gamma_k is derived and, introducing as an
application a simple truncation, the standard one-loop beta-function of N=1 SYM
theory is obtained.Comment: 17 pages, LaTeX, some remarks added, misprints corrected, to appear
in Phys. Rev.
Endogenous annexin A1 is a novel protective determinant in nonalcoholic steatohepatitis in mice
Macrophage-derived AnxA1 plays a functional role in modulating hepatic inflammation and fibrogenesis during NASH progression, suggesting the possible use of AnxA1 analogs for therapeutic control of this disease
The Distance to the Hyades Cluster Based on Hubble Space Telescope Fine Guidance Sensor Parallaxes
Trigonometric parallax observations made with the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) 3 of seven Hyades members in six ïŹelds of view have been analyzed along with their proper motions to determine the distance to the cluster. Knowledge of the convergent point and mean proper motion of the Hyades is critical to the derivation of the distance to the center of the cluster. Depending on the choice of the proper-motion system, the derived cluster center distance varies by 9%. Adopting a reference distance of 46.1 pc or m ÏȘ M Ï 3.32, which is derived from the ground-based parallaxes in the General Catalogue of Trigonometric Stellar Parallaxes (1995 edition), the FK5/PPM proper-motion system yields a distance 4% larger, while the Hanson system yields a distance 2% smaller. The HST FGS parallaxes reported here yield either a 14% or 5% larger distance, depending on the choice of the proper-motion system. Orbital parallaxes (Torres et al.) yield an average distance 4% larger than the reference distance. The variation in the distance derived from the HST data illustrates the importance of the proper-motion system and the individual proper motions to the derivation of the distance to the Hyades center; therefore, a full utilization of the HST FGS parallaxes awaits the establishment of an accurate and consistent proper-motion system
Wess-Zumino Terms in Supersymmetric Gauge Theories
The Wess-Zumino term is constructed for supersymmetric QCD with two colors
and flavors, and is shown to correctly reproduce the anomalous Ward identities.
Supersymmetric QCD is also shown not to have topologically stable skyrmion
solutions because of baryon flat directions, which allow them to unwind. The
generalization of these results to other supersymmetric theories with quantum
modified constraints is discussed.Comment: 4 pages (revtex
Report of the LHC Computing Grid Project. RTAG 12: Collaborative Tools
This document is the final report of the LHC Computing Grid (LCG) Project's Requirements and Technical Assessment Group (RTAG 12) on Collaborative Tools. It presents a summary of the requirements of the LHC collaborations for Collaborative Tools, assesses the current status of those tools in common use, discusses likely relevant future development, and provides recommendations for action by the LCG, the collaborations, and CERN for the immediate and long-term future. The requirements and assessments were assembled from formal and informal interactions between members of the RTAG, representatives of the LHC collaborations, CERN IT, and experts in the field of Collaborative Tools
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