141,781 research outputs found
MicroRNA dysregulation and esophageal cancer development depend on the extent of zinc dietary deficiency
open9siopenFong, Louise Y.; Taccioli, Cristian; Jing, Ruiyan; Smalley, Karl J.; Alder, Hansjuerg; Jiang, Yubao; Fadda, Paolo; Farber, John L.; Croce, Carlo M.Fong, Louise Y.; Taccioli, Cristian; Jing, Ruiyan; Smalley, Karl J.; Alder, Hansjuerg; Jiang, Yubao; Fadda, Paolo; Farber, John L.; Croce, Carlo M
HI and CO in the circumstellar environment of the oxygen-rich AGB star RX Lep
Circumstellar shells around AGB stars are built over long periods of time
that may reach several million years. They may therefore be extended over large
sizes (~1 pc, possibly more), and different complementary tracers are needed to
describe their global properties. In the present work, we combined 21-cm HI and
CO rotational line data obtained on an oxygen-rich semi-regular variable, RX
Lep, to describe the global properties of its circumstellar environment. With
the SEST, we detected the CO(2-1) rotational line from RX Lep. The line profile
is parabolic and implies an expansion velocity of ~4.2 km/s and a mass-loss
rate ~1.7 10^-7 Msun/yr (d = 137 pc). The HI line at 21 cm was detected with
the Nancay Radiotelescope on the star position and at several offset positions.
The linear shell size is relatively small, ~0.1 pc, but we detect a trail
extending southward to ~0.5 pc. The line profiles are approximately Gaussian
with an FWHM ~3.8 km/s and interpreted with a model developed for the detached
shell around the carbon-rich AGB star Y CVn. Our HI spectra are well-reproduced
by assuming a constant outflow (Mloss = 1.65 10^-7 Msun/yr) of ~4 10^4 years
duration, which has been slowed down by the external medium. The spatial offset
of the HI source is consistent with the northward direction of the proper
motion, lending support to the presence of a trail resulting from the motion of
the source through the ISM, as already suggested for Mira, RS Cnc, and other
sources detected in HI. The source was also observed in SiO (3 mm) and OH (18
cm), but not detected. The properties of the external parts of circumstellar
shells around AGB stars should be dominated by the interaction between stellar
outflows and external matter for oxygen-rich, as well as for carbon-rich,
sources, and the 21-cm HI line provides a very useful tracer of these regions.Comment: 15 pages, 9 figures, accepted for publication in A&
The radial pulsation of AI Aurigae
We present an analysis of eleven years of Stromgren by photometry of the red
semiregular variable star AI Aurigae. An early period determination of 63.9
days is confirmed by the long-term light curve behaviour. The light curve shows
semi-regular changes with a mean period of 65 days reaching an amplitude of 0.6
mag in some cycles. The b-y colour changes perfectly parallel the V light
curve, suggesting radial oscillation to be the main reason for the observed
variations. We estimate the main characteristics of the star (mass, radius,
effective temperature) that suggest radial pulsation in fundamental or first
overtone mode.Comment: 7 pages, 3 figures, accepted for publication in A&
An Equivariant Main Conjecture in Iwasawa Theory and Applications
We construct a new class of Iwasawa modules, which are the number field
analogues of the p-adic realizations of the Picard 1-motives constructed by
Deligne in the 1970s and studied extensively from a Galois module structure
point of view in our recent work. We prove that the new Iwasawa modules are of
projective dimension 1 over the appropriate profinite group rings. In the
abelian case, we prove an Equivariant Main Conjecture, identifying the first
Fitting ideal of the Iwasawa module in question over the appropriate profinite
group ring with the principal ideal generated by a certain equivariant p-adic
L-function. This is an integral, equivariant refinement of the classical Main
Conjecture over totally real number fields proved by Wiles in 1990. Finally, we
use these results and Iwasawa co-descent to prove refinements of the
(imprimitive) Brumer-Stark Conjecture and the Coates-Sinnott Conjecture, away
from their 2-primary components, in the most general number field setting. All
of the above is achieved under the assumption that the relevant prime p is odd
and that the appropriate classical Iwasawa mu-invariants vanish (as conjectured
by Iwasawa.)Comment: 52 page
Cristian science in Al-Andalus
Este estudio recopila toda la información historiográfica existente acerca
de la pervivencia en al-Ándalus de la ciencia preislámica, esto es, de aquella de
tradición romana y cristiana. Principalmente perduró durante el Emirato y el Califato
andalusí (s. VIII – principios del s. XI). Las ciencias analizadas son la
Astrología, por su fundamento científico en la Astronomía, la Medicina y la Agronomía.
Junto a ellas se complementa la investigación con las aportaciones de la
Geografía y la Historia como disciplinas humanísticasThis study collects all existing historiographical information about the
survival of pre-Islamic science, that is, that of Roman and Christian tradition, in
al-Andalus. Mainly it endured during the Andalusian Emirate and Caliphate (8th
century – early 11th century). The sciences which will be analyzed are Astrology
(because of its scientific basis in Astronomy), Medicine, and Agronomy. In addition,
this research is supplemented with the contributions of Geography and History as
humanistic discipline
Senior Recital: Cristian Larios, Baritone
Kemp Recital Hall April 7, 2018 Saturday Afternoon 5:00p.m
G345.45+1.50: An expanding ring-like structure with massive star formation
Ring-like structures in the ISM are commonly associated with high-mass stars.
Kinematic studies of large structures in GMCs toward these ring-like structures
may help us to understand how massive stars form. The origin and properties of
the ring-like structure G345.45+1.50 is investigated through observations of
the 13CO(3-2) line. The aim of the observations is to determine the kinematics
in the region and to compare physical characteristics estimated from gas
emission with those previously determined using dust continuum emission. The
13CO(3-2) line was mapped toward the whole ring using the APEX telescope. The
ring is found to be expanding with a velocity of 1.0 km/s, containing a total
mass of 6.9e3 Msun, which agrees well with that determined using 1.2 mm dust
continuum emission. An expansion timescale of 3e6 yr and a total energy of 7e46
erg are estimated. The origin of the ring might have been a supernova
explosion, since a 35.5 cm source, J165920-400424, is located at the center of
the ring without an infrared counterpart. The ring is fragmented, and 104
clumps were identified with diameters of between 0.3 and 1.6 pc, masses of
between 2.3 and 7.5e2 Msun, and densities of between 1.0e2 and 1.0e4 cm^-3. At
least 18% of the clumps are forming stars, as is shown in infrared images.
Assuming that the clumps can be modeled as Bonnor-Ebert spheres, 13 clumps are
collapsing, and the rest of them are in hydrostatic equilibrium with an
external pressure with a median value of 4e4 K cm^-3. In the region, the
molecular outflow IRAS 16562-3959 is identified, with a velocity range of 38.4
km/s, total mass of 13 Msun, and kinematic energy of 7e45 erg. Finally, five
filamentary structures were found at the edge of the ring with an average size
of 3 pc, a width of 0.6 pc, a mass of 2e2 Msun, and a column density of 6e21
cm^-2
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