2,112 research outputs found
Characterization of Lunar Farside Plains
The Moon contains broad and isolated areas of plains that have been recognized as mare, cryptomare, impact ejecta, or impact melt. These deposits have been extensively studied on the lunar nearside by remote sensing via telescopes and numerous spacecraft, and in some cases, in situ robotically and by astronauts. Only recently have the deposits on the entire farside been able to be observed and evaluated to the same degree. There are spatially extensive plains deposits located throughout the lunar farside highlands whose formation has remained ambiguous. Many of the plains deposits in the lunar farside highlands display higher albedos than mare materials. Some deposits are located in close proximity to relatively younger impact craters suggesting that plains could be composed of cryptomare or ejecta materials. Some deposits are within the range in which ejecta from large basin-forming events (e.g., SPA and Orientale) likely distributed large amounts of ejecta across the surface. Here we are conducting a series of observations and models in order to resolve the nature and origin of lunar farside plains deposits. Understanding these plains is important for understanding the volcanic and impact histories of the lunar farside, and is important for future mapping and thermal modeling studies
Little Higgs Models and Precision Electroweak Data
We study the low energy limit of Little Higgs models. The method consists in
eliminating the heavy fields using their classical equations of motion in the
infinite mass limit. After the elimination of the heavy degrees of freedom we
can directly read off deviations from the precision electroweak data. We also
examine the effects on the low energy precision experiments.Comment: Misprint in eps3 for the custodial model corrected and additional
discussion of the triplet higg
Z boson pair production at LHC in a stabilized Randall-Sundrum scenario
We study the Z boson pair production at LHC in the Randall-Sundrum scenario
with the Goldberger-Wise stabilization mechanism. It is shown that
comprehensive account of the Kaluza-Klein graviton and radion effects is
crucial to probe the model: The KK graviton effects enhance the cross section
of on the whole so that the resonance peak of the radion becomes
easy to detect, whereas the RS effects on the process are
rather insignificant. The and invariant-mass distributions are presented
to study the dependence of the RS model parameters. The production of
longitudinally polarized Z bosons, to which the SM contributions are
suppressed, is mainly due to KK gravitons and the radion, providing one of the
most robust methods to signal the RS effects. The sensitivity bounds
on with are also obtained such that
the effective weak scale of order 5 TeV can be experimentally
probed.Comment: 28 pages, LaTex file, 18 eps figure
Proximity to a Nearly Superconducting Quantum Critical Liquid
The coupling between superconductors and a quantum critical liquid that is
nearly superconducting provides natural interpretation for the Josephson effect
over unexpectedly long junctions, and the remarkable stripe-spacing dependence
of the critical temperature in LSCO and YBCO superconductors.Comment: four two-column pages, no figure
On Adler-Bell-Jackiw Anomaly in 3-brane Scenario
We investigate the ABJ anomaly in the framework of an effective field theory
for a 3-brane scenario and show that the contribution from induced gravity on
the brane depends on both the topological structure of the bulk space-time and
the embedding of the brane in the bulk. This fact implies the existence of a
non-trivial vacuum structure of bulk quantum gravity. Furthermore, we argue
that this axial gravitational anomaly may not necessarily be cancelled by
choosing the matter content on the brane since it could be considered as a
possible effect from bulk quantum gravity.Comment: 17 pages, RevTex, no figures. Some further misprints are correcte
The Simplest Little Higgs
We show that the SU(3) little Higgs model has a region of parameter space in
which electroweak symmetry breaking is natural and in which corrections to
precision electroweak observables are sufficiently small. The model is anomaly
free, generates a Higgs mass near 150 GeV, and predicts new gauge bosons and
fermions at 1 TeV.Comment: 13 pages + appendix, typos corrected, version to appear in JHE
Thermoelectric power of MgBBe
We investigated thermoelectric power of MgBBe (,
0.2, 0.3, 0.4, and 0.6). decreases systematically with , suggesting
that the hole density increases. Our band calculation shows that the increase
occurs in the -band. With the hole-doping, decreases.
Implication of this phenomenon is discussed within the BCS framework. While the
Mott formula explains only the linear part of at low temperature,
incorporation of electron-phonon interaction enables us to explain over
wide temperature range including the anomalous behavior at high temperature.Comment: 4 pages, 4 figure
Split Fermions in Extra Dimensions and Exponentially Small Cross-Sections at Future Colliders
We point out a dramatic new experimental signature for a class of theories
with extra dimensions, where quarks and leptons are localized at slightly
separated parallel ``walls'' whereas gauge and Higgs fields live in the bulk of
the extra dimensions. The separation forbids direct local couplings between
quarks and leptons, allowing for an elegant solution to the proton decay
problem. We show that scattering cross sections for collisions of fermions
which are separated in the extra dimensions vanish exponentially at energies
high enough to probe the separation distance. This is because the separation
puts a lower bound on the attainable impact parameter in the collision. We
present cross sections for two body high energy scattering and estimate the
power with which future colliders can probe this scenario, finding sensitivity
to inverse fermion separations of order 10-70 TeV.Comment: 18 pages, 3 figure
The role of the IGF axis in IGFBP-1 and IGF-I induced renal enlargement in Snell dwarf mice
Insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is generally
believed to inhibit IGF action in the circulation. In contrast, IGFBP-1
has been reported to interact with cell surfaces and enhance IGF-I action
locally in some tissues. Renal IGFBP-1 levels are found elevated in
various conditions characterized by renal growth (e.g. diabetes mellitus,
hypokalemia). To test whether IGFBP-1 is a renotropic factor, IGFBP-1 was
administered alone or in combination with IGF-I to Snell dwarf mice, an in
vivo model without compensatory feedback effects on growth hormone (GH)
secretion. In three control groups of Snell dwarf mice, placebo, GH or
IGF-I was administered. Compared with placebo, kidney weight increased in
all treated groups, however, with different effects on kidney morphology.
Administration of IGF-I, alone or in combination with IGFBP-1, tended to
increase glomerular volume, while no changes were seen in the other
groups. Administration of IGFBP-1 or IGFBP-1+IGF-I both caused dilatation
of the thin limbs of Henle's loop, while GH or IGF-I administration had no
visible effect. Furthermore, IGF-I administration resulted in an increased
mean number of nuclei per cortical area and renal weight, whereas GH,
IGF-I+IGFBP-1 or IGFBP-1 caused a decreased renal nuclei number. In situ
hybridization and immunohistochemistry showed specific changes of the
renal IGF system expression patterns in the different groups.
Particularly, IGFBP-1 administration resulted in extensive changes in the
mRNA expression of the renal IGF system, whereas the other administration
regimen resulted in less prominent modifications. In contrast,
administration of IGFBP-1 and IGFBP-1+IGF-I resulted in identical changes
in the protein expression of the renal IGF system. Our results indicate
that IGFBP-1, alone or in combination with IGF-I, demonstrated effects on
the renal tubular system that differ from the effects of IGF-I
Investigation of electron irradiation-induced magnetism in layered MoS2 single crystals
By using higher acceleration energies than the displacement energy of Mo atoms, the electron irradiation on the layered MoS2 single crystals is found to be an effective and simple method to induce the diamagnetic to ferromagnetic phase transition persisting up to room temperature. The easy axis can be controllable by regulating the electron dose and the acceleration energy. The ferromagnetic states are largely attributed to the strain around the vacancies.clos
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