1,334 research outputs found
Long Lived Large Type II Strings: decay within compactification
Motivated also by recent revival of interest about metastable string states
(as cosmic strings or in accelerator physics), we study the decay, in presence
of dimensional compactification, of a particular superstring state, which was
proven to be remarkably long-lived in the flat uncompactified scenario. We
compute the decay rate by an exact numerical evaluation of the imaginary part
of the one-loop propagator. For large radii of compactification, the result
tends to the fully uncompactified one (lifetime T = const M^5/g^2), as
expected, the string mainly decaying by massless radiation. For small radii,
the features of the decay (emitted states, initial mass dependence,....)
change, depending on how the string wraps on the compact dimensions.Comment: 32 pages, 24 text plus appendices, 4 figure
Modular Invariance and Characteristic Numbers
We show that a general miraculous cancellation formula, the divisibility of
certain characteristic numbers and some other topologiclal results are con-
sequences of the modular invariance of elliptic operators on loop spaces.
Previously we have shown that modular invariance also implies the rigidity of
many elliptic operators on loop spaces.Comment: 14 page
Ovine hepatogenous photosensitivity caused by the plant Nidorella foetida (Thunb.) DC. (Asteraceae)
Following a field outbreak of hepatogenous photosensitivity in sheep, an identical condition was reproduced experimentally by dosing 2 sheep with green, homogenized, Nidorella foetida material, collected from the camp where the outbreak occurred. This is a rare, unpalatable, aromatic shrub found in swampy places in the south-western Cape Province. The main lesion was a hepatosis, characterized by peripheral coagulative necrosis and midzonal degeneration in the 2 acute cases and mild bile duct proliferation and hepatic regeneration in the more chronic field case. Botanical, toxicological, clinical and pathological data are given.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201
The Legacy of ERA, Privatization and the Policy Ratchet
This article explores the ways in which the neo-liberal impetus toward the privatization of state schooling signalled in the Education Reform Act 1988 (ERA) has become embedded in the English school system. Four main points are made. First, that ERA itself was of huge strategic rather than substantive importance as far as privatization is concerned. Second, by tracing the lineage of privatization from ERA onwards a 'ratchet' effect of small and incremental policy moves can be identified, which have disseminated, embedded and naturalized privatization within public sector provision. Third, that while privatization has been taken up and taken much further by New Labour than it had been by the Conservatives there are differences between the two sets of governments in the role of privatization in education policy and the role of the state. Fourth, the participation of private providers in the planning and delivery of state services has put the private sector at the very heart of policy. At points the article draws upon interviews conducted with private sector providers. © 2008 Sage Publications
Measurement Near Threshold of 9-Be(3-He, Pi) to the A = 12 Isobaric Triplet by Recoil Detection
This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit
Multibeam Maser Survey of methanol and excited OH in the Magellanic clouds: new detections and maser abundance estimates
‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.12888.xPeer reviewe
Two-fermion bound state in a Bose-Einstein condensate
A nonlinear Schr\"odinger equation is derived for the dynamics of a beam of
ultracold fermionic atoms traversing a Bose-Einstein condensate. The condensate
phonon modes are shown to provide a nonlinear medium for the fermionic atoms. A
two-fermion bound state is predicted to arise, and the signature of the bound
state in a nonlinear atom optics experiment is discussed.Comment: 4 pages, 1 figure
The HO Southern Galactic Plane Survey (HOPS) - I. Techniques and HO maser data
The definitive version can be found at: http://onlinelibrary.wiley.com/ Copyright Royal Astronomical SocietyWe present first results of the HO Southern Galactic Plane Survey (HOPS), using the Mopra Radio Telescope with a broad-band backend and a beam size of about 2 arcmin. We have observed 100 deg of the southern Galactic plane at 12mm (19.5-27.5GHz), including spectral line emission from HO masers, multiple metastable transitions of ammonia, cyanoacetylene, methanol and radio recombination lines. In this paper, we report on the characteristics of the survey and HO maser emission. We find 540 HO masers, of which 334 are new detections. The strongest maser is 3933Jy and the weakest is 0.7Jy, with 62 masers over 100Jy. In 14 maser sites, the spread in the velocity of the HO maser emission exceeds 100kms. In one region, the HO maser velocities are separated by 351.3kms. The rms noise levels are typically between 1 and 2Jy, with 95 per cent of the survey under 2Jy. We estimate completeness limits of 98 per cent at around 8.4Jy and 50 per cent at around 5.5Jy. We estimate that there are between 800 and 1500 HO masers in the Galaxy that are detectable in a survey with similar completeness limits to HOPS. We report possible masers in NH (11,9) and (8,6) emission towards G19.61-0.23 and in the NH (3,3) line towards G23.33-0.30.Peer reviewe
A systematic cross-search for radio/infrared counterparts of XMM-Newton sources
We present a catalog of cross-correlated radio, infrared and X-ray sources
using a very restrictive selection criteria with an IDL-based code developed by
us. The significance of the observed coincidences was evaluated through Monte
Carlo simulations of synthetic sources following a well-tested protocol. We
found 3320 coincident radio/X-ray sources with a high statistical significance
characterized by the sum of error-weighted coordinate differences. For 997 of
them, 2MASS counterparts were found. The percentage of chance coincidences is
less than 1%. X-ray hardness ratios of well-known populations of objects were
used to provide a crude representation of their X-ray spectrum and to make a
preliminary diagnosis of the possible nature of unidentified X-ray sources. The
results support the fact that the X-ray sky is largely dominated by Active
Galactic Nuclei at high galactic latitudes (|b| >= 10^\circ). At low galactic
latitudes (|b| <= 10^\circ) most of unidentified X-ray sources (~94%) lie at
|b| <= 2^\circ. This result suggests that most of the unidentified sources
found toward the Milky Way plane are galactic objects. Well-known and
unidentified sources were classified in different tables with their
corresponding radio/infrared and X-ray properties. These tables are intended as
a useful tool for researchers interested in particular identifications.Comment: Accepted for publication in Ap&SS. 47 pages, 10 figures. On-line
material: figures and table
A probabilistic model for gene content evolution with duplication, loss, and horizontal transfer
We introduce a Markov model for the evolution of a gene family along a
phylogeny. The model includes parameters for the rates of horizontal gene
transfer, gene duplication, and gene loss, in addition to branch lengths in the
phylogeny. The likelihood for the changes in the size of a gene family across
different organisms can be calculated in O(N+hM^2) time and O(N+M^2) space,
where N is the number of organisms, is the height of the phylogeny, and M
is the sum of family sizes. We apply the model to the evolution of gene content
in Preoteobacteria using the gene families in the COG (Clusters of Orthologous
Groups) database
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