21,857 research outputs found
The preferentially magnified active nucleus in IRAS F10214+4724 - II. Spatially resolved cold molecular gas
We present JVLA observations of the cold (CO (1-0)) molecular gas in IRAS
F10214+4724, a lensed ULIRG at z=2.3 with an obscured active nucleus. The
galaxy is spatially and spectrally well-resolved in the CO (1-0) emission line.
A CO (1-0) counter-image is detected at the 3-sigma level. Five of the 42 km/s
channels (with >5-sigma detections) are mapped back into the source plane and
their total magnification posterior PDFs sampled. This reveals a roughly linear
arrangement, tentatively a rotating disk. We derive a molecular gas mass of
M_gas = 1.2 +- 0.2 x 10^10 M_sun, assuming a ULIRG L_{CO}-to-M_{gas} conversion
ratio of \alpha = 0.8 M_sun / (K km/s pc^2) that agrees well with the derived
range of \alpha = 0.3 - 1.3 for separate dynamical mass estimates at assumed
inclinations of i = 90 - 30 degrees. Based on the AGN and CO (1-0) peak
emission positions and the lens model, we predict a distortion of the CO
Spectral Line Energy Distribution (SLED) where higher order J lines that may be
partially excited by AGN heating will be preferentially lensed owing to their
smaller solid angles and closer proximity to the AGN and therefore the cusp of
the caustic. Comparison with other lensing inversion results shows that the
narrow line region and AGN radio core in IRAS F10214+4724 are preferentially
lensed by a factor >~ 3 and 11 respectively, relative to the molecular gas
emission. This distorts the global continuum emission Spectral Energy
Distribution (SED) and suggests caution in unsophisticated uses of IRAS
F10214+4724 as an archetype high-redshift ULIRG. We explore two Large Velocity
Gradient (LVG) models, incorporating spatial CO (1-0) and (3-2) information and
present tentative evidence for an extended, low excitation cold gas component
that implies that the total molecular gas mass in IRAS F10214+4724 is a factor
>~2 greater than that calculated using spatially unresolved CO observations.Comment: Dedicated to Steve Rawlings. Accepted for publication in MNRAS. 16
pages, 11 figure
Character of Locally Inequivalent Classes of States and Entropy of Entanglement
In this letter we have established the physical character of pure bipartite
states with the same amount of entanglement in the same Schmidt rank that
either they are local unitarily connected or they are incomparable. There exist
infinite number of deterministically locally inequivalent classes of pure
bipartite states in the same Schmidt rank (starting from three) having same
amount of entanglement. Further, if there exists incomparable states with same
entanglement in higher Schmidt ranks (greater than three), then they should
differ in at least three Schmidt coefficients.Comment: 4 pages, revtex4, no figure, accepted in Physical Review A (rapid
communications
Conditions for entanglement transformation between a class of multipartite pure states with generalized Schmidt decompositions
In this note we generalize Nielsen's marjoization criterion for the
convertibility of bipartite pure states [Phys. Rev. Lett \textbf{83},
436(1999)] to a special class of multipartite pure states which have
generalized Schmidt decompositions.Comment: 3 pages (Revetex 4), no figures. A brief note on entanglement
transformation. Comments are welcom
The relaxation of OH (v = 1) and OD (v = 1) by H2O and D2O at temperatures from 251 to 390 K
We report rate coefficients for the relaxation of OH(v = 1) and OD(v = 1) by H2O and D2O as a function of temperature between 251 and 390 K. All four rate coefficients exhibit a negative dependence on temperature. In Arrhenius form, the rate coefficients for relaxation (in units of 10–12 cm3 molecule–1 s–1) can be expressed as: for OH(v = 1) + H2O between 263 and 390 K: k = (2.4 ± 0.9) exp((460 ± 115)/T); for OH(v = 1) + D2O between 256 and 371 K: k = (0.49 ± 0.16) exp((610 ± 90)/T); for OD(v = 1) + H2O between 251 and 371 K: k = (0.92 ± 0.16) exp((485 ± 48)/T); for OD(v = 1) + D2O between 253 and 366 K: k = (2.57 ± 0.09) exp((342 ± 10)/T). Rate coefficients at (297 ± 1 K) are also reported for the relaxation of OH(v = 2) by D2O and the relaxation of OD(v = 2) by H2O and D2O. The results are discussed in terms of a mechanism involving the formation of hydrogen-bonded complexes in which intramolecular vibrational energy redistribution can occur at rates competitive with re-dissociation to the initial collision partners in their original vibrational states. New ab initio calculations on the H2O–HO system have been performed which, inter alia, yield vibrational frequencies for all four complexes: H2O–HO, D2O–HO, H2O–DO and D2O–DO. These data are then employed, adapting a formalism due to Troe (J. Troe, J. Chem. Phys., 1977, 66, 4758), in order to estimate the rates of intramolecular energy transfer from the OH (OD) vibration to other modes in the complexes in order to explain the measured relaxation rates—assuming that relaxation proceeds via the hydrogen-bonded complexes
Low myo-inositol and high glutamine levels in brain are associated with neuropsychological deterioration after induced hyperammonemia
The neuropsychological effect of hyperammonemia is variable. This study tests the hypothesis that the effect of ammonia on the neuropsychological function in patients with cirrhosis is determined by the ability of the brain to buffer ammonia-induced increase in glutamine within the astrocyte by losing osmolytes like myo-inositol (mI) and not by the magnitude of the induced hyperammonemia. Fourteen cirrhotic patients with no evidence of overt hepatic encephalopathy were given a 75-g amino acid (aa) solution mimicking the hemoglobin molecule to induce hyperammonemia. Measurement of a battery of neuropsychological function tests including immediate memory, ammonia, aa, and short-echo time proton magnetic resonance spectroscopy were performed before and 4 h after administration of the as solution. Eight patients showed deterioration in the Immediate Memory Test at 4 h. Demographic factors, severity of liver disease, change in plasma ammonia, and as profiles after the as solution were similar in those that showed a deterioration compared with those who did not. In patients who showed deterioration in the memory test, the mI-to-creatine ratio (mI/Cr) was significantly lower at baseline than those that did not deteriorate. In contrast, the glutamate/glutamine-to-Cr ratio was significantly greater in the patients that deteriorated. The observation that deterioration in the memory test scores was greater in those with lower mI/Cr supports the hypothesis that the neuropsychological effects of induced hyperammonemia is determined by the capacity of the brain to handle ammonia-induced increase in glutamine
Quantum Phase Transitions in Anti-ferromagnetic Planar Cubic Lattices
Motivated by its relation to an -hard problem, we analyze the
ground state properties of anti-ferromagnetic Ising-spin networks embedded on
planar cubic lattices, under the action of homogeneous transverse and
longitudinal magnetic fields. This model exhibits a quantum phase transition at
critical values of the magnetic field, which can be identified by the
entanglement behavior, as well as by a Majorization analysis. The scaling of
the entanglement in the critical region is in agreement with the area law,
indicating that even simple systems can support large amounts of quantum
correlations. We study the scaling behavior of low-lying energy gaps for a
restricted set of geometries, and find that even in this simplified case, it is
impossible to predict the asymptotic behavior, with the data allowing equally
good fits to exponential and power law decays. We can therefore, draw no
conclusion as to the algorithmic complexity of a quantum adiabatic ground-state
search for the system.Comment: 7 pages, 13 figures, final version (accepted for publication in PRA
Structure and superconductivity of two different phases of Re3W
Two superconducting phases of Re(3)W have been found with different physical properties. One phase crystallizes in a noncentrosymmetric cubic (alpha-Mn) structure and has a superconducting transition temperature T(c) of 7.8 K. The other phase has a hexagonal centrosymmetric structure and is superconducting with a T(c) of 9.4 K. Switching between the two phases is possible by annealing the sample or remelting it. The properties of both phases of Re(3)W have been characterized by powder neutron diffraction, magnetization, and resistivity measurements. The temperature dependences of the lower and upper critical fields have been measured for both phases. These are used to determine the penetration depths and the coherence lengths for these systems
Expression of alphav integrins and vitronectin receptor identity in breast cancer cells.
In the present study we have used fluorocytometry and immunoprecipitation to characterize the expression of alphav-containing integrins in a panel of eight human breast cancer cell lines and one normal human mammary epithelial line. We show that the classical vitronectin receptor alphavbeta3 is expressed in only one cell line (MDA-MB-231), whereas alphavbeta5 is expressed on all breast cancer cell lines and alphavbeta1 is expressed on the majority. Using adherence assays to purified ligands in the presence and absence of function-blocking monoclonal antibodies, we have demonstrated that alphavbeta5 mediates adhesion to vitronectin in the majority of these cells. In one cell line, ZR75-1, alphavbeta1 contributes significantly to adhesion to immobilized vitronectin. The formation of focal adhesions containing the alphav and beta1 subunits on vitronectin is also demonstrated by indirect immunofluorescence
Deployable antenna phase A study
Applications for large deployable antennas were re-examined, flight demonstration objectives were defined, the flight article (antenna) was preliminarily designed, and the flight program and ground development program, including the support equipment, were defined for a proposed space transportation system flight experiment to demonstrate a large (50 to 200 meter) deployable antenna system. Tasks described include: (1) performance requirements analysis; (2) system design and definition; (3) orbital operations analysis; and (4) programmatic analysis
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