467 research outputs found
Realization of BEC-BCS crossover physics in a compact oven-loaded magneto-optic trap apparatus
We report on a simple oven-loaded magneto-optical trap (MOT) apparatus for
the creation of both molecular Bose-Einstein condensates (mBEC) and degenerate
Fermi gases (DFGs) of lithium. The apparatus does not require a Zeeman slower
or a 2D MOT nor does it require any separation or differential pumping between
the effusive atom source and the science chamber. The result is an exceedingly
simple, inexpensive, and compact vacuum system ideal for miniaturization. We
discuss our work in the context of other realizations of quantum degenerate
gases by evaporation in optical dipole traps and illustrate that our apparatus
meets the key requirements of atom number and trap lifetime. We also
demonstrate with this system the production of a mBEC, and we use it to observe
the pairing gap of a strongly interacting two-component DFG in the BEC-BCS
crossover regime.Comment: 12 pages, 7 figure
Andromeda II as a merger remnant
Using N-body simulations we study the origin of prolate rotation recently
detected in the kinematic data for And II, a dSph satellite of M31. We propose
an evolutionary model for the origin of And II involving a merger between two
disky dwarf galaxies whose structural parameters differ only in their disk
scale lengths. The dwarfs are placed on a radial orbit towards each other with
their angular momenta inclined by 45 deg to the orbital plane and by 90 deg
with respect to each other. After 5 Gyr of evolution the merger remnant forms a
stable triaxial galaxy with rotation only around the longest axis. The origin
of this rotation is naturally explained as due to the symmetry of the initial
configuration which leads to the conservation of angular momentum components
along the direction of the merger. The stars originating from the two dwarfs
show significantly different surface density profiles while having very similar
kinematics in agreement with the properties of separate stellar populations in
And II. We also study an alternative scenario for the formation of And II, via
tidal stirring of a disky dwarf galaxy. While intrinsic rotation occurs
naturally in this model as a remnant of the initial rotation of the disk, it is
mostly around the shortest axis of the stellar component. The rotation around
the longest axis is induced only occasionally and remains much smaller that the
system's velocity dispersion. We conclude that although tidal origin of the
velocity distribution in And II cannot be excluded, it is much more naturally
explained within the scenario involving a past merger event. Thus, in
principle, the presence of prolate rotation in dSph galaxies of the Local Group
and beyond may be used as an indicator of major mergers in their history or
even as a way to distinguish between the two scenarios of their formation.Comment: 5 pages, 6 figures, accepted for publication in MNRAS Letter
Clinicoprognostical features of endometrial cancer patients with somatic mtDNA mutations
Somatic mitochondrial DNA (mtDNA) mutations
have been found in a subset of endometrial cancers (EC) from
different populations. We have investigated the relationship
between mtDNA changes and clinical and pathological
variables of women affected by EC. mtDNA mutations were
detected both in early (3/32; 9%) and in advanced (1/8;
12%) stages of uterine tumors. However, patients carrying
the mtDNA mutations or the normal mtDNA sequence had
indistinguishable clinicopathological data, including age,
clinical stage, histological grade and type or depth of myometrial
invasion. It is noteworthy that mtDNA mutations
were not detected in hyperplastic endometrial tissues or in
ECs coexisting with hyperplasia, nor in a single case of
endometrial stromal sarcoma. LOH at the tumor suppressor
genes RB1 and TP53 as well as p16INK4A alterations (LOH,
gene deletion) were found in tumors carrying mtDNA
mutations. These results suggest that somatic mtDNA
mutations are detected in a subset of ECs, although they are
unrelated to clinicopathological variables of cancer
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