132,577 research outputs found
On strictly singular operators between separable Banach spaces
Let and be separable Banach spaces and denote by \sss\sss(X,Y) the
subset of \llll(X,Y) consisting of all strictly singular operators. We study
various ordinal ranks on the set \sss\sss(X,Y). Our main results are
summarized as follows. Firstly, we define a new rank \rs on \sss\sss(X,Y).
We show that \rs is a co-analytic rank and that dominates the rank
introduced by Androulakis, Dodos, Sirotkin and Troitsky [Israel J. Math., 169
(2009), 221-250]. Secondly, for every we construct a Banach
space with an unconditional basis such that \sss\sss(\ell_p, Y_p) is a
co-analytic non-Borel subset of \llll(\ell_p,Y_p) yet every strictly singular
operator satisfies . This answers a
question of Argyros.Comment: 20 pages, no figures; Mathematika, to appea
The pain of low status: the relationship between subjective socio-economic status and analgesic prescriptions in a Scottish community sample
There is a strong positive relationship between objective measures of socioeconomic status (OSS) and general health. However, there is an increasing interest in the relationship between health and subjective socioeconomic status (SSS), which describes one’s perceived rank in relation to the rest of society, based on factors such as income, occupation, and education. While the relationship between SSS and general health is well2established, the relationship between SSS and pain has received little attention. Gathering both self2report questionnaire data and General Practitioner medical data from a large representative community sample in Scotland between 2012 and 2013 ( N = 1824), we investigated the relationship between SSS and prescriptions for analgesic drugs. We found that higher levels of SSS significantly predicted lower odds of participants having been prescribed at least one analgesic drug in the previous six months. We obtained this result even after controlling for OSS2related variables (education, occupational status, and geographical location) and demographic variables (age and gender). This suggests that, just like the relationship between SSS and general health, SSS has important effects on pain that go beyond the influence of OSS
The Josephson Effect in Single Spin Superconductors
The Josephson Effect provides a primary signature of single spin
superconductivity (SSS), the as yet unobserved superconducting state which was
proposed recently as a low temperature phase of half-metallic antiferromagnets.
These materials are insulating in the spin-down channel but are metallic in the
spin-up channel. The SSS state is characterized by a unique form of p-wave
pairing within a single spin channel. We develop the theory of a rich variety
of Josephson effects that arise due to the form of the SSS order parameter.
Tunneling is allowed at a SSS-SSS' junction but of course depends on the
relative orientation of their order parameters. No current flows between an SSS
and an s-wave BCS system due to their orthogonal symmetries, which potentially
can be used to distinguish SSS from other superconducting states. Single spin
superconductors also offer a means to probe other materials, where tunneling is
a litmus test for any form of ``triplet'' order parameter.Comment: 4 pages, RevTeX, 2 PostScript figures included, to appear in J. Phys.
and Chem. of Solid
Impact of Satellite Sea Surface Salinity Observations on ENSO Predictions from the NASA/GMAO Seasonal Forecast System
We assess the impact of satellite sea surface salinity (SSS) observations on dynamical ENSO forecasts. Assimilation of SSS improves the mixed layer depth (MLD) and modulates the Kelvin waves associated with ENSO. In column 2, the initialization differences between experiments that assimilate SSS minus those withholding SSS assimilation are presented. Column 3 shows examples of forecasts generated for the different phases of ENSO assimilating the different satellite SSS. In general, for all phases of ENSO, SSS assimilation improves forecasts. The far right column compares ensemble means for assimilation of individual and combined SMOS, Aquarius, and SMAP SSS forecasts. Finally, the latest forecasts are presented comparing assimilation versus no- assimilation of satellite SSS for single forecasts over the last year
Supersoft X-ray sources in M31: II. ROSAT-detected supersoft sources in the ROSAT, Chandra and XMM eras
We have performed Chandra observations during the past 3 years of 5 of the
M31 supersoft X-ray sources (SSS) discovered with ROSAT. Surprisingly, only one
of these sources has been detected, despite a predicted detection of about
20-80 counts. This has motivated a thorough check of the ROSAT M31 survey I
data, including a relaxation of the hardness ratio requirement used to select
SSS. This increases the number of SSS identified in survey I by 7. We then
carried out a comparison with the ROSAT M31 survey II dataset which had
hitherto not been explicitly investigated for SSS. We find that most of the
ROSAT survey I sources are not detected, and only two new SSS are identified.
The low detection rate in the ROSAT survey II and our Chandra observations
implies that the variability time scale of SSS is a few months. If the majority
of these sources are close-binary SSS with shell hydrogen burning, it further
implies that half of these sources predominantly experience large mass transfer
rates.Comment: accepted for publ. in ApJ; 2 ps-figures; high-quality figures
available at http://www.mpe.mpg.de/~jcg/publis.htm
Complex group algebras of the double covers of the symmetric and alternating groups
We prove that the double covers of the alternating and symmetric groups are
determined by their complex group algebras. To be more precise, let
be an integer, a finite group, and let \AAA and \SSS^\pm denote the
double covers of \Al_n and \Sy_n, respectively. We prove that \CC G\cong
\CC \AAA if and only if G\cong \AAA, and \CC G\cong \CC
\SSS^+\cong\CC\SSS^- if and only if G\cong \SSS^+ or \SSS^-. This in
particular completes the proof of a conjecture proposed by the second and
fourth authors that every finite quasi-simple group is determined uniquely up
to isomorphism by the structure of its complex group algebra. The known results
on prime power degrees and relatively small degrees of irreducible (linear and
projective) representations of the symmetric and alternating groups together
with the classification of finite simple groups play an essential role in the
proofs.Comment: 27 pages, the previous version is revised slightly, to appear in
Algebra & Number Theor
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