4,015 research outputs found
Alien Registration- Cote, Joseph I. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29212/thumbnail.jp
Structure of the SMC - Stellar component distribution from 2MASS data
The spatial distribution of the SMC stellar component is investigated from
2MASS data. The morphology of the different age populations is presented. The
center of the distribution is calculated and compared with previous
estimations. The rotation of the stellar content and possible consequence of
dark matter presence are discussed. The different stellar populations are
identified through a CMD diagram of the 2MASS data. Isopleth contour maps are
produced in every case, to reveal the spatial distribution. The derived density
profiles are discussed. The older stellar population follows an exponential
profile at projected diameters of about 5 kpc (~5 deg) for the major axis and
~4 kpc for the minor axis, centred at RA: 0h:51min, Dec: -73deg 7' (J2000.0).
The centre coordinates are found the same for all the different age population
maps and are in good accordance with the kinematical centre of the SMC. However
they are found considerably different from the coordinates of the centre of the
gas distribution. The fact that the older population found on an exponential
disk, gives evidence that the stellar content is rotating, with a possible
consequence of dark matter presence. The strong interactions between the MCs
and the MilkyWay might explain the difference in the distributions of the
stellar and gas components. The lack in the observed velocity element, that
implies absence of rotation, and contradicts with the consequences of
exponential profile of the stellar component, may also be a result of the
gravitational interactions.Comment: 7 Pages, 6 figures, accepted for publication in A&
Obscure Overt Gastrointestinal Bleeding Due To Isolated Small Bowel Angiomatosis
Isolated small bowel angiomatosis is a rare entity with a distinctive endoscopic appearance. A multidisciplinary approach is often required to diagnose and treat these complex lesions. We present 2 cases of isolated small bowel angiomatosis, and illustrate the endoscopic findings that may guide similar diagnoses
Structure and Stability of Two-Dimensional Complexes of C_20 Fullerenes
Two-dimensional complexes of C_20 fullerenes connected to each other by
covalent bonds have been studied. Several isomers with different types of
intercluster bonds have been revealed. The lifetimes of the (C_20)_MxM systems
with M = 2 and 3 have been directly calculated at T = 1800 - 3300 K making use
of molecular dynamics. It has been shown that these complexes lose their
periodic cluster structure due to either coalescence of two fullerenes C_20 or
decay of C_20 fullerenes. The activation energies of these processes exceed 2
eV.Comment: 17 pages, 5 figure
Strong enhancement of drag and dissipation at the weak- to strong- coupling phase transition in a bi-layer system at a total Landau level filling nu=1
We consider a bi-layer electronic system at a total Landau level filling
factor nu =1, and focus on the transition from the regime of weak inter-layer
coupling to that of the strongly coupled (1,1,1) phase (or ''quantum Hall
ferromagnet''). Making the assumption that in the transition region the system
is made of puddles of the (1,1,1) phase embedded in a bulk of the weakly
coupled state, we show that the transition is accompanied by a strong increase
in longitudinal Coulomb drag, that reaches a maximum of approximately
. In that regime the longitudinal drag is increased with decreasing
temperature.Comment: four pages, one included figur
Massive Spin Collective Mode in Quantum Hall Ferromagnet
It is shown that the collective spin rotation of a single Skyrmion in quantum
Hall ferromagnet can be regarded as precession of the entire spin texture in
the external magnetic field, with an effective moment of inertia which becomes
infinite in the zero g-factor limit. This low-lying spin excitation may
dramatically enhance the nuclear spin relaxation rate via the hyperfine
interaction in the quantum well slightly away from filling factor equal one.Comment: 4 page
A Magnetically Torqued Disk Model for Be Stars
Despite extensive study, the mechanisms by which Be star disks acquire high
densities and angular momentum while displaying variability on many time scales
are still far from clear. In this paper, we discuss how magnetic torquing may
help explain disk formation with the observed quasi-Keplerian (as opposed to
expanding) velocity structure and their variability. We focus on the effects of
the rapid rotation of Be stars, considering the regime where centrifugal forces
provide the dominant radial support of the disk material. Using a kinematic
description of the angular velocity, vphi(r), in the disk and a parametric
model of an aligned field with a strength B(r) we develop analytic expressions
for the disk properties that allow us to estimate the stellar surface field
strength necessary to create such a disk for a range of stars on the
main-sequence. The model explains why disks are most common for main-sequence
stars at about spectral class B2 V. The earlier type stars with very fast and
high density winds would require unacceptably strong surface fields (> 10^3
Gauss) to form torqued disks, while the late B stars (with their low mass loss
rates) tend to form disks that produce only small fluxes in the dominant Be
diagnostics. For stars at B2 V the average surface field required is about 300
Gauss. The predicted disks provide an intrinsic polarization and a flux at
Halpha comparable to observations. We also discuss whether the effect on field
containment of the time dependent accumulation of matter in the flux tubes/disk
can help explain some of the observed variability of Be star disks.Comment: ApJ, in press. 46 pages, 12 figure
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