1,114 research outputs found
An \u3ci\u3eab initio\u3c/i\u3e Potential Energy Surface for the Ne-CO
A new ab initio two-dimensional potential energy surface for the Ne-CO interaction is described. The surface was obtained by the supermolecule method at the CCSD(T) level of theory. It is compared with several experimental data sets and with the symmetry-adapted perturbation theory (SAPT) surface of Moszynski et al. [J. Phys. Chem. A 101, 4690 (1997)]. The new surface gives modestly better predictions of experimental results that depend on close approach of Ne to CO, but does not describe the ground state geometry as well as the SAPT surface
Detection of a Substantial Molecular Gas Reservoir in a brightest cluster galaxy at z = 1.7
We report the detection of CO(2-1) emission coincident with the brightest
cluster galaxy (BCG) of the high-redshift galaxy cluster SpARCS1049+56, with
the Redshift Search Receiver (RSR) on the Large Millimetre Telescope (LMT). We
confirm a spectroscopic redshift for the gas of z = 1.7091+/-0.0004, which is
consistent with the systemic redshift of the cluster galaxies of z = 1.709. The
line is well-fit by a single component Gaussian with a RSR resolution-corrected
FWHM of 569+/-63 km/s. We see no evidence for multiple velocity components in
the gas, as might be expected from the multiple image components seen in
near-infrared imaging with the Hubble Space Telescope. We measure the
integrated flux of the line to be 3.6+/-0.3 Jy km/s and, using alpha_CO = 0.8
Msun (K km s^-1 pc^2)^-1 we estimate a total molecular gas mass of
1.1+/-0.1x10^11 Msun and a M_H2/M_star ~ 0.4. This is the largest gas reservoir
detected in a BCG above z > 1 to date. Given the infrared-estimated star
formation rate of 860+/-130 Msun/yr, this corresponds to a gas depletion
timescale of ~0.1Gyr. We discuss several possible mechanisms for depositing
such a large gas reservoir to the cluster center -- e.g., a cooling flow, a
major galaxy-galaxy merger or the stripping of gas from several galaxies -- but
conclude that these LMT data are not sufficient to differentiate between them.Comment: accepted for publication in ApJ Letter
Effects of global O-GlcNAcylation on galectin gene-expression profiles in human cancer cell lines
Background/Aim: The effects of O-linked β-N-acetyl-D-glucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase (OGA) inhibitors on galectin gene expression profiles were examined in MCF7, HT-29, and HL-60 cancer cell lines. Materials and Methods: Cell cultures were treated for 24 h with OGA inhibitor thiamet G or OGT inhibitor 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-5-thio-α-D-glucopyranose, and global O-GlcNAc levels and expression of galectin genes were determined using an immunodot blot assay and real-time quantitative polymerase chain reaction. Results: Two galectin genes, LGALS3 in MCF7 cells and LGALS12 in HL-60 cells, were up-regulated by O-GlcNAc, whereas other cell-specific galectins were unresponsive to changes in O-GlcNAc level. Of interest, basal levels of O-GlcNAc in resting HL-60 and HT-29 cells were significantly higher than those in cells differentiated into neutrophilic or enterocytic lineages, respectively. Conclusion: O-GlcNAc-mediated signaling pathways may be involved in regulating the expression of only a limited number of galectin genes. Additional O-GlcNAc-dependent mechanisms may work at the protein level (galectin secretion and intracellular localization) and warrant further investigation
A case of carotid body paraganglioma and haemangioblastoma of the spinal cord in a patient with the N131K missense mutation in the VHL gene
The article describes paraganglioma case in woman with von Hippel–Lindau disease. She was found to be a carrier of a rare germline mutation in the VHL gene (393C>A; N131K). The patient developed large, untypical for von Hippel–Lindau disease, carotid body paraganglioma at the common carotid artery bifurcation. The carotid body paraganglioma coexisted with the haemangioblastoma situated intramedullary in region C5/C6. The haemangioblastoma reached the right-sided dorsal part of the spinal cord in section C5/C6. It produced radicular symptoms within C5/C6, followed by the later paresis of the right limbs. The haemangioblastoma was resected completely. Twelve months after the operation, the spinal symptoms receded and the carotid body paraganglioma still was asymptomatic. The current case of carotid body paraganglioma in patient with the 393C>A (N131K) missense mutation in the VHL gene, supports association of this specific mutation and VHL disease type 2, and suggests its correlation with susceptibility to paragangliomas
On the Clustering of Sub-millimeter Galaxies
We measure the angular two-point correlation function of sub-millimeter
galaxies (SMGs) from 1.1-millimeter imaging of the COSMOS field with the AzTEC
camera and ASTE 10-meter telescope. These data yields one of the largest
contiguous samples of SMGs to date, covering an area of 0.72 degrees^2 down to
a 1.26 mJy/beam (1-sigma) limit, including 189 (328) sources with S/N greater
than 3.5 (3). We can only set upper limits to the correlation length r_0,
modeling the correlation function as a power-law with pre-assigned slope.
Assuming existing redshift distributions, we derive 68.3% confidence level
upper limits of r_0 < 6-8 h^-1 Mpc at 3.7 mJy, and r_0 < 11-12 h^-1 Mpc at 4.2
mJy. Although consistent with most previous estimates, these upper limits imply
that the real r_0 is likely smaller. This casts doubts on the robustness of
claims that SMGs are characterized by significantly stronger spatial
clustering, (and thus larger mass), than differently selected galaxies at
high-redshift. Using Monte Carlo simulations we show that even strongly
clustered distributions of galaxies can appear unclustered when sampled with
limited sensitivity and coarse angular resolution common to current
sub-millimeter surveys. The simulations, however, also show that unclustered
distributions can appear strongly clustered under these circumstances. From the
simulations, we predict that at our survey depth, a mapped area of two
degrees^2 is needed to reconstruct the correlation function, assuming smaller
beam sizes of future surveys (e.g. the Large Millimeter Telescope's 6" beam
size). At present, robust measures of the clustering strength of bright SMGs
appear to be below the reach of most observations.Comment: 23 pages, 8 figures, accepted for publication in The Astrophysical
Journa
Entropic Uncertainty Relations in Quantum Physics
Uncertainty relations have become the trademark of quantum theory since they
were formulated by Bohr and Heisenberg. This review covers various
generalizations and extensions of the uncertainty relations in quantum theory
that involve the R\'enyi and the Shannon entropies. The advantages of these
entropic uncertainty relations are pointed out and their more direct connection
to the observed phenomena is emphasized. Several remaining open problems are
mentionedComment: 35 pages, review pape
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