1,173 research outputs found
Homogeneity of the 16S rDNA sequence among geographically disparate isolates of Taylorella equigenitalis
BACKGROUND: At present, six accessible sequences of 16S rDNA from Taylorella equigenitalis (T. equigenitalis) are available, whose sequence differences occur at a few nucleotide positions. Thus it is important to determine these sequences from additional strains in other countries, if possible, in order to clarify any anomalies regarding 16S rDNA sequence heterogeneity. Here, we clone and sequence the approximate full-length 16S rDNA from additional strains of T. equigenitalis isolated in Japan, Australia and France and compare these sequences to the existing published sequences. RESULTS: Clarification of any anomalies regarding 16S rDNA sequence heterogeneity of T. equigenitalis was carried out. When cloning, sequencing and comparison of the approximate full-length 16S rDNA from 17 strains of T. equigenitalis isolated in Japan, Australia and France, nucleotide sequence differences were demonstrated at the six loci in the 1,469 nucleotide sequence. Moreover, 12 polymorphic sites occurred among 23 sequences of the 16S rDNA, including the six reference sequences. CONCLUSION: High sequence similarity (99.5% or more) was observed throughout, except from nucleotide positions 138 to 501 where substitutions and deletions were noted
The theoretical capacity of the Parity Source Coder
The Parity Source Coder is a protocol for data compression which is based on
a set of parity checks organized in a sparse random network. We consider here
the case of memoryless unbiased binary sources. We show that the theoretical
capacity saturate the Shannon limit at large K. We also find that the first
corrections to the leading behavior are exponentially small, so that the
behavior at finite K is very close to the optimal one.Comment: Added references, minor change
Collider signatures of sneutrino cold dark matter
Decays of sneutrinos are considered in the case that in the presence of lepton-number violation in the sneutrino sector the lighter tau-sneutrino is the Lightest Supersymmetric Particle and the Cold Dark Matter in the Universe. In such circumstances the signals from sparticle decays differ considerably from the 'standard' case where the lightest neutralino is the Lightest Supersymmetric Particle and it is found that in a wide range of parameters compatible with the sneutrino Cold Dark Matter hypothesis signatures characteristic for such a scenario should be easily observable at for example a Next Linear Collider
Physics at the Linear Collider
The physics at the planned colliders is discussed around three main
topics corresponding to different manifestations of symmetry breaking:
physics in the no Higgs scenario, studies of the properties of the Higgs and
precision tests of SUSY. A comparison with the LHC is made for all these cases.
The mode of the linear collider will also be reviewed.Comment: 31 pages, 12 figures. Invited talk given at the Fifth Workshop on
High Energy Physics Phenomenology, Inter-University Centre for Astronomy and
Astrophysics, Pune, India, January 12 - 26, 199
Long Range Dynamics Related to Magnetic Impurity in the 2D Heisenberg Antiferromagnet
We consider a magnetic impurity in the two-dimensional Heisenberg
antifferomagnet with long range antiferromagnetic order. At low temperature the
impurity magnetic susceptibility has a Curie term () and a
logarithmic correction (). We calculate the correction and
derive related Ward identity for the impurity-spin-wave vertex.Comment: 5 pages, 6 figure
Poststarburst Models of LINERs
Since the discovery of low-ionization nuclear emission-line regions in many
galaxies (LINERs), it has been recognized that they constitute a class of
active galactic nuclei (AGNs) which are thought to be powered by gas accretion
onto a central, supermassive black hole. LINERs are observed in approximately
one third of galaxies in the local universe and it has been often thought that
they harbor an AGN-like central engine with moderate activity. However, some
LINERs show no direct evidence for AGNs such as broad emission lines, radio
jets, hard X-ray emission, spectral energy distributions which are inconsistent
with starlight, and so on. For such LINERs (a subset of type 2 LINERs), we
present new poststarburst models which explain some of their most important
optical narrow emission-line ratios. In these models, the ionization sources
are planetary nebula nuclei (PNNs) with temperature of ~ 10^5 K which appear in
the late-phase evolution of intermediate-mass stars with mass between ~ 3
M_solar and ~ 6 M_solar. Such PNNs left in a typical starburst nucleus can
produce an Halpha luminosity of L(Halpha) ~ 10^38 ergs s^-1 for typical
poststarburst LINERs and ~ 10^39 ergs s^-1 only in exceptionally bright cases.
The PNN phase lasts until the death of the lowest-mass stars formed in the
starburst, which is ~ 5 x 10^8 yr for an assumed lower limit of the initial
mass function of 3 M_solar. This long duration appears consistent with the
observed higher frequency of occurrence of LINERs if every galaxy could
experience the starburst activity several times in its life. We therefore
propose that some LINERs which show no direct evidence for AGNs may be
poststarburst nuclei powered by a cluster of PNNs.Comment: 8 pages, 6 figures, emulateapj.sty; To appear in the September 2000
issue of the Astronomical Journa
Magnetic Impurity in the two-dimensional Heisenberg Antiferromagnet
We analyze the ground state properties of the two-dimensional quantum
antiferromagnet with a S=1/2 Kondo impurity. Perturbation theory around the
strong Kondo coupling limit is developed and the results compared with studies,
based on exact diagonalization of small clusters. We find that at intermediate
coupling the impurity is partially screened and the magnetization locally
suppressed. A local singlet between the impurity and the host spin is formed
asymptotically.Comment: 12 REVTex pages, 4 Postscript figure
The Subaru COSMOS 20: Subaru Optical Imaging of the HST COSMOS Field with 20 Filters
We present both the observations and the data reduction procedures of the
Subaru COSMOS 20 project that is an optical imaging survey of the HST COSMOS
field, carried out by using Suprime-Cam on the Subaru Telescope with the
following 20 optical filters: 6 broad-band (B, g', V, r', i', and z'), 2
narrow-band (NB711 and NB816), and 12 intermediate-band filters (IA427, IA464,
IA484, IA505, IA527, IA574, IA624, IA679, IA709, IA738, IA767, and IA827). A
part of this project is described in Taniguchi et al. (2007) and Capak et al.
(2007) for the six broad-band and one narrow-band (NB816) filter data. In this
paper, we present details of the observations and data reduction for remaining
13 filters (the 12 IA filters and NB711). In particular, we describe the
accuracy of both photometry and astrometry in all the filter bands. We also
present optical properties of the Suprime-Cam IA filter system in Appendix.Comment: 15 pages, 8 figures, 7 tables; accepted for publication in PASJ on
October 2, 201
Solar models and solar neutrino oscillations
We provide a summary of the current knowledge, theoretical and experimental,
of solar neutrino fluxes and of the masses and mixing angles that characterize
solar neutrino oscillations. We also summarize the principal reasons for doing
new solar neutrino experiments and what we think may be learned from the future
measurements.Comment: Submitted to the Neutrino Focus Issue of New Journal of Physics at
http://www.njp.or
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