379 research outputs found
Erosional features as indicators of thrust fault activity (Nankai Trough, Japan)
A submarine channel system and basal ramps of a Quaternary mass-transport deposit (MTD) are shown to represent thrust fault activity in the Nankai accretionary wedge. Variations in channel bed slope, height and width of submarine channels and gullies indicate uplift and sediment bypass seaward from a margin-dominating out-of-sequence thrust, the megasplay fault (MSF), at < 1.67-1.46 Ma. Between ~ 1.05 and 0.85 Ma, a younger mass-transport deposit (MTD 6) was detached at different depths. Demonstrating the significant deformation observed in the study area, the direction of transport of MTD 6 differs 30o-45o from the strike of scarps and ramps at its base, which are parallel to the structural contours of thrust anticlines underneath. This character contrasts to the geometries frequently documented in frontally-emergent submarine landslides. In parallel, oblique basal ramps form significant boundaries between zones of MTD 6 with distinct acoustic and, suggestively, petrophysical properties. As a result of this study, we postulate that developed channel systems can erode the upper continental slope and lead to bypass of substantial volumes of sediment to distal parts of accretionary wedges. This process bears the potential of generating periods of more intense thrust-wedge deformation, at least locally, than those predicted by mathematical and physical models based on present-day taper geometries. On a regional scale, the observations in this paper are important as they indicate a more diffuse distribution of deformation in the Nankai accretionary wedge than previously assumed for the MSF region
Surface analysis of tiles and samples exposed to the first JET campaigns with the ITER-Like Wall
This paper reports on the first post-mortem analyses of tiles removed from
JET after the first campaigns with the ITER-like Wall (ILW) during 2011-2 [1].
Tiles from the divertor have been analysed by the Ion Beam Analysis (IBA)
techniques Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction
Analysis (NRA) and by Secondary Ion Mass Spectrometry (SIMS) to determine the
amount of beryllium deposition and deuterium retention in the tiles exposed to
the scrape-off layer. Films 10-20 microns thick were present at the top of Tile
1, but only very thin films (<1 micron) were found in the shadowed areas and on
other divertor tiles. The total amount of Be found in the divertor following
the ILW campaign was a factor of ~9 less that the material deposited in the
2007-9 carbon campaign, after allowing for the longer operations in 2007-9.Comment: 10 pages, 5 figures. This is an author-created, un-copyedited version
of an article accepted for publication in Physica Scripta. IOP Publishing Ltd
is not responsible for any errors or omissions in this version of the
manuscript or any version derived from i
The Large Magellanic Cloud and the Distance Scale
The Magellanic Clouds, especially the Large Magellanic Cloud, are places
where multiple distance indicators can be compared with each other in a
straight-forward manner at considerable precision. We here review the distances
derived from Cepheids, Red Variables, RR Lyraes, Red Clump Stars and Eclipsing
Binaries, and show that the results from these distance indicators generally
agree to within their errors, and the distance modulus to the Large Magellanic
Cloud appears to be defined to 3% with a mean value of 18.48 mag, corresponding
to 49.7 Kpc. The utility of the Magellanic Clouds in constructing and testing
the distance scale will remain as we move into the era of Gaia.Comment: 23 pages, accepted for publication in Astrophysics and Space Science.
From a presentation at the conference The Fundamental Cosmic Distance Scale:
State of the Art and the Gaia Perspective, Naples, May 201
Abelian Hidden Sectors at a GeV
We discuss mechanisms for naturally generating GeV-scale hidden sectors in
the context of weak-scale supersymmetry. Such low mass scales can arise when
hidden sectors are more weakly coupled to supersymmetry breaking than the
visible sector, as happens when supersymmetry breaking is communicated to the
visible sector by gauge interactions under which the hidden sector is
uncharged, or if the hidden sector is sequestered from gravity-mediated
supersymmetry breaking. We study these mechanisms in detail in the context of
gauge and gaugino mediation, and present specific models of Abelian GeV-scale
hidden sectors. In particular, we discuss kinetic mixing of a U(1)_x gauge
force with hypercharge, singlets or bi-fundamentals which couple to both
sectors, and additional loop effects. Finally, we investigate the possible
relevance of such sectors for dark matter phenomenology, as well as for low-
and high-energy collider searches.Comment: 43 pages, no figures; v2: to match JHEP versio
Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010) produced in 500 GeV/c pi^- nucleon interactions
We report differential cross sections for the production of D*(2010) produced
in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as
functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also
report the D* +/- charge asymmetry and spin-density matrix elements as
functions of these variables. Investigation of the spin-density matrix elements
shows no evidence of polarization. The average values of the spin alignment are
\eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles,
respectively.Comment: LaTeX2e (elsart.cls). 13 pages, 6 figures (eps files). Submitted to
Physics Letters
Complementarity of the CERN Large Hadron Collider and the International Linear Collider
The next-generation high-energy facilities, the CERN Large Hadron Collider
(LHC) and the prospective International Linear Collider (ILC), are
expected to unravel new structures of matter and forces from the electroweak
scale to the TeV scale. In this report we review the complementary role of LHC
and ILC in drawing a comprehensive and high-precision picture of the mechanism
breaking the electroweak symmetries and generating mass, and the unification of
forces in the frame of supersymmetry.Comment: 14 pages, 17 figures, to be published in "Supersymmetry on the Eve of
the LHC", a special volume of European Physical Journal C, Particles and
Fields (EPJC) in memory of Julius Wes
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Novos e raros registros de Euglenophyta incolores na Planície Costeira do Rio Grande do Sul, Brasil
Asymmetries in the production of lambda zero, cascade minus, and omega minus hyperons in 500 GeV/c pi minus-Nucleon Interactions
Using data from Fermilab fixed-target experiment E791, we have measured
particle-antiparticle production asymmetries for lambda zero, cascade minus,
and omega minus hyperons in pi minus-nucleon interactions at 500 GeV/c. The
asymmetries are measured as functions of Feynman-x (x_F) and pt^2 over the
ranges of -0.12 GE x_F LE 0.12 and 0 GE pt^2 LE 4 (GeV/c)^2. We find
substantial asymmetries, even at x_F = 0. We also observe leading-particle-
type asymmetries which qualitatively agree with theoretical predictions.Comment: 15 pages, including 5 figures and 2 tables. To be submitted to Phys.
Lett.
- …