151,625 research outputs found
Classification of direct limits of even Cuntz-circle algebras
We prove a classification theorem for purely infinte simple C*-algebras that
is strong enough to show that the tensor products of two different irrational
rotation algebras with the same even Cuntz algebra are isomorphic. In more
detail, let C be be the class of simple C*-algebras A which are direct limits A
= lim A_k, in which each A_k is a finite direct sum of algebras of the form
C(X) \otimes M_n \otimes O_m, where m is even, O_m is the Cuntz algebra, X is
either a point, a compact interval, or the circle S^1, and each map A_k ---> A
is approximately absorbing. ("Approximately absorbing" is defined in Section 1
of the paper.) We show that two unital C*-algebras A and B in the class C are
isomorphic if and only if (K_0 (A), [1_A], K_1 (A)) is isomorphic to (K_0 (B),
[1_B], K_1 (B)). This class is large enough to exhaust all possible K-groups:
if G_0 and G_1 are countable odd torsion groups and g is in G_0, then there is
a C*-algebra A in C with (K_0 (A), [1_A], K_1 (A)) isomorphic to (G_0, g, G_1).
The class C contains the tensor products of irrational rotation algebras with
even Cuntz algebras. It is also closed under several natural operations.Comment: LaTeX, 71 pages (in 10pt type). This replacement corrects assorted
misprints and is in smaller type. The paper has been accepted in the Memoirs
of the AM
Telomere length as a predictor of response to Pioglitazone in patients with unremitted depression: a preliminary study.
We studied peripheral leukocyte telomere length (LTL) as a predictor of antidepressant response to PPAR-γ agonist in patients with unremitted depression. In addition we examined correlation between LTL and the insulin resistance (IR) status in these subjects. Forty-two medically stable men and women ages 23-71 with non-remitted depression participated in double-blind placebo-controlled add-on of Pioglitazone to treatment-as-usual. Oral glucose tolerance tests were administered at baseline and at 12 weeks. Diagnostic evaluation of psychiatric disorders was performed at baseline and mood severity was followed weekly throughout the duration of the trial. At baseline, no differences in LTL were detected by depression severity, duration or chronicity. LTL was also not significantly different between insulin-resistant and insulin-sensitive subjects at baseline. Subjects with longer telomeres exhibited greater declines in depression severity in the active arm, but not in a placebo arm, P=0.005, r=-0.63, 95% confidence interval (95% CI)=(-0.84,-0.21). In addition, LTL predicted improvement in insulin sensitivity in the group overall and did not differ between intervention arms, P=0.036, r=-0.44, 95% CI=(-0.74,0.02) for the active arm, and P=0.026, r=-0.50, 95% CI=(-0.78,-0.03) for the placebo arm. LTL may emerge as a viable predictor of antidepressant response. An association between insulin sensitization and LTL regardless of the baseline IR status points to potential role of LTL as a non-specific moderator of metabolic improvement in these patients
I-V characteristics of short superconducting nanowires with different bias and shunt: a dynamic approach
We derived the I-V characteristics of short nanowire in the circuit with and
without resistive and inductive shunt. For that we used numerical calculations
in the framework of time-dependent Ginzburg-Landau equations with different
relaxation times for the amplitude and phase dynamics. We also derived
dependence of the I-V characteristics on flux in superconducting quantum
interference device (SQUID) made of such two weak links.Comment: 5.4 pages and 7 figure
Explaining the observed velocity dispersion of dwarf galaxies by baryonic mass loss during the first collapse
In the widely adopted LambdaCDM scenario for galaxy formation, dwarf galaxies
are the building blocks of larger galaxies. Since they formed at relatively
early epochs when the background density was relatively high, they are expected
to retain their integrity as satellite galaxies when they merge to form larger
entities. Although many dwarf spheroidal galaxies (dSphs) are found in the
galactic halo around the Milky Way, their phase space density (or velocity
dispersion) appears to be significantly smaller than that expected for
satellite dwarf galaxies in the LambdaCDM scenario. In order to account for
this discrepancy, we consider the possibility that they may have lost a
significant fraction of their baryonic matter content during the first infall
at the Hubble expansion turnaround. Such mass loss arises naturally due to the
feedback by relatively massive stars which formed in their centers briefly
before the maximum contraction. Through a series of N-body simulations, we show
that the timely loss of a significant fraction of the dSphs initial baryonic
matter content can have profound effects on their asymptotic half-mass radius,
velocity dispersion, phase-space density, and the mass fraction between
residual baryonic and dark matter.Comment: 6 pages, 6 figures, accepted for publication in the Ap
- …
