106,015 research outputs found
Eccentricity Evolution of Extrasolar Multiple Planetary Systems due to the Depletion of Nascent Protostellar Disks
Most extrasolar planets are observed to have eccentricities much larger than
those in the solar system. Some of these planets have sibling planets, with
comparable masses, orbiting around the same host stars. In these multiple
planetary systems, eccentricity is modulated by the planets' mutual secular
interaction as a consequence of angular momentum exchange between them. For
mature planets, the eigenfrequencies of this modulation are determined by their
mass and semi-major axis ratios. But, prior to the disk depletion, self gravity
of the planets' nascent disks dominates the precession eigenfrequencies. We
examine here the initial evolution of young planets' eccentricity due to the
apsidal libration or circulation induced by both the secular interaction
between them and the self gravity of their nascent disks. We show that as the
latter effect declines adiabatically with disk depletion, the modulation
amplitude of the planets' relative phase of periapse is approximately invariant
despite the time-asymmetrical exchange of angular momentum between planets.
However, as the young planets' orbits pass through a state of secular
resonance, their mean eccentricities undergo systematic quantitative changes.
For applications, we analyze the eccentricity evolution of planets around
Upsilon Andromedae and HD168443 during the epoch of protostellar disk
depletion. We find that the disk depletion can change the planets' eccentricity
ratio. However, the relatively large amplitude of the planets' eccentricity
cannot be excited if all the planets had small initial eccentricities.Comment: 50 pages including 11 figures, submitted to Ap
Liquefaction Assessment and Lateral Spreading in Nantou, Taiwan
On September 21, 1999, Taiwan was struck by an earthquake, called Chi-Chi earthquake, one of the largest in 100 years. The epicenter was located 12.5 km west of the Sun Moon Lake (Northern Latitude 23.85°) Eastern Longitude 120.78°), with focal depth of 8 km, and magnitude of Mw=7.6 (USGS). This earthquake caused heavy casualties and severe property damages around central Taiwan. It was found that this earthquake resulted in sand boiling, differential settlement on the ground and lateral spreading around part of the Maolou River bank in Nantou City. Field investigation, geological exploration and in situ tests, which include 14 borings with standard penetration tests and 8 cone penetration test soundings, were conducted to demonstrate the soil profiles and to perform soil liquefaction potential assessment. The ground failure due to spreading liquefaction near Maolou River bank was also described. The result revealed that soils about 5-8 meters below the ground surface contains fine to medium silty sand or sandy silt which is the same strata as the highest liquefaction potential based on SPT-N and CPT-qc liquefaction simplified procedures. It is also shown that the critical depth also has the physical properties similar to the boiled sand taken from the sand volcanoes
Large collective Lamb shift of two distant superconducting artificial atoms
Virtual photons can mediate interaction between atoms, resulting in an energy
shift known as a collective Lamb shift. Observing the collective Lamb shift is
challenging, since it can be obscured by radiative decay and direct atom-atom
interactions. Here, we place two superconducting qubits in a transmission line
terminated by a mirror, which suppresses decay. We measure a collective Lamb
shift reaching 0.8% of the qubit transition frequency and exceeding the
transition linewidth. We also show that the qubits can interact via the
transmission line even if one of them does not decay into it.Comment: 7+5 pages, 4+2 figure
The AF structure of non commutative toroidal Z/4Z orbifolds
For any irrational theta and rational number p/q such that q|qtheta-p|<1, a
projection e of trace q|qtheta-p| is constructed in the the irrational rotation
algebra A_theta that is invariant under the Fourier transform. (The latter is
the order four automorphism U mapped to V, V mapped to U^{-1}, where U, V are
the canonical unitaries generating A_theta.) Further, the projection e is
approximately central, the cut down algebra eA_theta e contains a Fourier
invariant q x q matrix algebra whose unit is e, and the cut downs eUe, eVe are
approximately inside the matrix algebra. (In particular, there are Fourier
invariant projections of trace k|qtheta-p| for k=1,...,q.) It is also shown
that for all theta the crossed product A_theta rtimes Z_4 satisfies the
Universal Coefficient Theorem. (Z_4 := Z/4Z.) As a consequence, using the
Classification Theorem of G. Elliott and G. Gong for AH-algebras, a theorem of
M. Rieffel, and by recent results of H. Lin, we show that A_theta rtimes Z_4 is
an AF-algebra for all irrational theta in a dense G_delta.Comment: 35 page
CD4+ T-cell responses to Epstein-Barr virus nuclear antigen EBNA1 in Chinese populations are highly focused on novel C-terminal domain-derived epitopes
Epstein-Barr virus nuclear antigen EBNA1, the one viral protein uniformly expressed in nasopharyngeal carcinoma (NPC), represents a prime target for T-cell-based immunotherapy. However, little is known about the EBNA1 epitopes, particularly CD4 epitopes, presented by HLA alleles in Chinese people, the group at highest risk for NPC. We analyzed the CD4 T-cell responses to EBNA1 in 78 healthy Chinese donors and found marked focusing on a small number of epitopes in the EBNA1 C-terminal region, including a DP5- restricted epitope that was recognized by almost half of the donors tested and elicited responses able to recognize EBNA1-expressing, DP5-positive target cells
Symmetric achromatic low-beta collider interaction region design concept
We present a new symmetry-based concept for an achromatic low-beta collider
interaction region design. A specially-designed symmetric Chromaticity
Compensation Block (CCB) induces an angle spread in the passing beam such that
it cancels the chromatic kick of the final focusing quadrupoles. Two such CCBs
placed symmetrically around an interaction point allow simultaneous
compensation of the 1st-order chromaticities and chromatic beam smear at the IP
without inducing significant 2nd-order aberrations to the particle trajectory.
We first develop an analytic description of this approach and explicitly
formulate 2nd-order aberration compensation conditions at the interaction
point. The concept is next applied to develop an interaction region design for
the ion collider ring of an electron-ion collider. We numerically evaluate
performance of the design in terms of momentum acceptance and dynamic aperture.
The advantages of the new concept are illustrated by comparing it to the
conventional distributed-sextupole chromaticity compensation scheme.Comment: 12 pages, 17 figures, to be submitted to Phys. Rev. ST Accel. Beam
The impact of materialistic values on Thai consumers’ brand engagement in self-concept for luxury products
Purpose: The present study was designed to determine whether brand engagement in self-concept was a function of materialistic values (social recognition, appealing appearance, financial success, defining success, acquisition centrality, pursuit of happiness) among Thai consumers of luxury goods. Design/Methodology/Approach: The participants were selected using multistage sampling on the basis of their shopping experience for luxury items. Multiple linear regression analysis was conducted to evaluate the best linear combination of materialistic values that could predict brand engagement in self-concept.
Findings: Appealing appearance, acquisition centrality, social recognition and defining success formed the significant variate that predicted brand engagement in self-concept. Practical Implications: Taken together, these findings support strong recommendations to marketing managers of luxury products on how to tap into consumers’ values in order to market a luxury brand. Originality/Value: The study addresses the symbolic value of luxury brands and how such brands and their brand images interact with how consumers view their own identities.peer-reviewe
Two resonant magnetic modes in an overdoped high- superconductor
A detailed inelastic neutron scattering study of the overdoped high
temperature copper oxide superconductor
reveals two distinct magnetic resonant modes in the superconducting state. The
modes differ in their symmetry with respect to exchange between adjacent copper
oxide layers. Counterparts of the mode with odd symmetry, but not the one with
even symmetry, had been observed before at lower doping levels. The observation
of the even mode resolves a long-standing puzzle, and the spectral weight ratio
of both modes yields an estimate of the onset of particle-hole spin-flip
excitations.Comment: Submitted to PR
- …