579 research outputs found
Comparison of clinical and environmental isolates of Legionella pneumophila obtained in the UK over 19 years
ABSTRACTBetween January 1980 and December 1998, 3458 cases of Legionnaires’ disease were reported to the national surveillance scheme in England and Wales. Of these, 463 (13.4%) were reported as proven by culture and isolation of Legionella spp., with 96.3% being Legionella pneumophila. Serogroup (Sgp), monoclonal antibody (mAb) subgrouping and restriction fragment length polymorphism (RFLP) analysis data were obtained for 321 (69.3%) of these, of which 284 were classified as being unrelated to any other isolate in the study. Typing data were also available for 117 unrelated environmental isolates of L. pneumophila obtained from England and Wales, giving a total of 401 unrelated isolates in the study. Of the clinical isolates, 88.0% were Sgp1, compared with only 42.7% of environmental isolates (p <0.001); 79.6% of clinical isolates were subgrouped as mAb2+, compared with only 12.8% of environmental isolates (p <0.001). RFLP typing identified 67 types among the 401 isolates, with clinical isolates showing significantly less diversity than environmental isolates (index of diversity (IOD) 0.944 vs. 0.958; p <0.05), with three RFLP types (1, 5 and 14) accounting for 40.0% of all clinical isolates. Combining the phenotypic and genotypic data resulted in 173 distinct phenons, with clinical isolates showing significantly less diversity than environmental isolates (IOD 0.964 vs. 0.996; p <0.01). Three phenons accounted for 30% of all clinical isolates. These data strongly suggest that some strains of L. pneumophila are more likely to cause human infection than would be expected from their distribution in the environment
Co-existence of organising pneumonia in a patient with Mycobacterium Avium Intracellulare pulmonary infection
Non-tuberculous mycobacterias (NTMs) have many clinical manifestations in humans, depending on the underlying immunological status. We present a patient with Mycobacterium avium intracellulare pulmonary infection and co-existing, biopsy proven non-granulomatous organising pneumonia in distinct regions within the lungs. Treatment consisting of anti-mycobacterial therapy and corticosteroids led to clinico-radiological resolution. This case represents a potential broader clinico-pathological manifestation of Mycobacterium avium intracellulare
Superconducting p-branes and Extremal Black Holes
In Einstein-Maxwell theory, magnetic flux lines are `expelled' from a black
hole as extremality is approached, in the sense that the component of the field
strength normal to the horizon goes to zero. Thus, extremal black holes are
found to exhibit the sort of `Meissner effect' which is characteristic of
superconducting media. We review some of the evidence for this effect, and do
present new evidence for it using recently found black hole solutions in string
theory and Kaluza-Klein theory. We also present some new solutions, which arise
naturally in string theory, which are non-superconducting extremal black holes.
We present a nice geometrical interpretation of these effects derived by
looking carefully at the higher dimensional configurations from which the lower
dimensional black hole solutions are obtained. We show that other extremal
solitonic objects in string theory (such as p-branes) can also display
superconducting properties. In particular, we argue that the relativistic
London equation will hold on the worldvolume of `light' superconducting
p-branes (which are embedded in flat space), and that minimally coupled zero
modes will propagate in the adS factor of the near-horizon geometries of
`heavy', or gravitating, superconducting p-branes.Comment: 22 pages, 2 figure
Equation of state of neutron star cores and spin down of isolated pulsars
We study possible impact of a softening of the equation of state by a phase
transition, or appearance of hyperons, on the spin evolution of of isolated
pulsars. Numerical simulations are performed using exact 2-D simulations in
general relativity. The equation of state of dense matter at supranuclear
densities is poorly known. Therefore, the accent is put on the general
correlations between evolution and equation of state, and mathematical
strictness. General conjectures referring to the structure of the one-parameter
families of stationary configurations are formulated. The interplay of the back
bending phenomenon and stability with respect to axisymmetric perturbations is
described. Changes of pulsar parameters in a corequake following instability
are discussed, for a broad choice of phase transitions predicted by different
theories of dense matter. The energy release in a corequake, at a given initial
pressure, is shown to be independent of the angular momentum of collapsing
configuration. This result holds for various types of phases transition, with
and without metastability. We critically review observations of pulsars that
could be relevant for the detection of the signatures of the phase transition
in neutron star cores.Comment: 7 pages, 11 figures, to appear in Astrophysics and Space Science, in
the proceedings of "Isolated Neutron Stars: from the Interior to the
Surface", edited by D. Page, R. Turolla and S. Zan
Constraining R-parity violating couplings using dimuon data at Tevatron Run-II
The dimuon plus dijet signal is analyzed in the top squark pair production at
Tevatron Run-II experiment and the total event rate is compared with the
existing dimuon data. This comparison rules out top squark mass upto 188(104)
GeV for the branching fraction 100%(50%) of top squark decay into the muon plus
quark via lepton number violating coupling. Interpretation of this limit in the
framework of R-parity violating(RPV) SUSY model puts limit on relevant RPV
coupling for a given top squark mass and other supersymmetric model parameters.
If \MST \lsim 180 GeV we found that the RPV couplings are roughly restricted
to be within which is at the same ballpark value obtained from
the neutrino data. The limits are very stringent for a scenario where top
squarks appear to be the next lightest supersymmetric particles.Comment: 7 pages, 3 figures,added minor clarifications,version to appear in
Phys. Lett.
Tuberculous pancreatitis complicated by ruptured splenic artery pseudoaneurysm
Tuberculous pancreatitis complicated by ruptured splenic artery pseudoaneurysm. M. Irfan, F. Thiavalappil, J. Nagaraj, T.H. Brown, D. Roberts, L. Mcknight, N.K. Harrison. Tuberculosis involving the pancreas is rare. We report a patient with pancreatic tuberculosis complicated by haemorrhage from a splenic artery pseudoaneurysm. As far as we are aware, the development of a splenic artery pseudoaneurysm in association with a large caseating mass of tuberculous pancreatic lymph nodes has not been reported previously. We review the literature and discuss the varied presentations of tuberculosis involving the pancreas or the pancreatic bed and its draining lymph nodes
Assessment of fluorescent amplified fragment length polymorphism analysis for epidemiological genotyping of Legionella pneumophila serogroup 1
n/
Factors influencing participation in outdoor physical activity promotion schemes: The case of South Staffordshire, England
Policy exhortations for promoting outdoor physical activity have increased considerably in England and Wales over the past 20 years. Despite a considerable number of schemes developing during this period to encourage physical activity and exercise, marked population-level changes in outdoor physical activity behaviour have not been seen. The paper explores the triggers to this participation using a five-fold classification: physical infrastructure; information infrastructure; administrative infrastructure; participant constraints and participant preferences. Through a series of interviews in a case study 'healthy exercise' scheme in South Staffordshire, a district local authority in England, these triggers to participation are identified and explored. It is concluded that whilst the infrastructure triggers can be manipulated by scheme providers in an attempt to improve scheme participation, participant triggers fall largely beyond the control of scheme providers. Research suggests, too, that participant triggers tend to be stronger than infrastructure ones. Because of this, where there is a lack of healthy exercise scheme success, this cannot necessarily be attributed to scheme providers as it might be as a result of user triggers. For the same reason, it might be beyond the influence of scheme providers to turn 'failing' exercise schemes into successful ones. © 2012 Copyright Taylor and Francis Group, LLC
Extinction risk and conservation of the world\u27s sharks and rays
The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondrichthyan fishes—sharks, rays, and chimaeras. We estimate that one-quarter are threatened according to IUCN Red List criteria due to overfishing (targeted and incidental). Large-bodied, shallow-water species are at greatest risk and five out of the seven most threatened families are rays. Overall chondrichthyan extinction risk is substantially higher than for most other vertebrates, and only one-third of species are considered safe. Population depletion has occurred throughout the world’s ice-free waters, but is particularly prevalent in the Indo-Pacific Biodiversity Triangle and Mediterranean Sea. Improved management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery
Demonstration of a novel technique to measure two-photon exchange effects in elastic scattering
The discrepancy between proton electromagnetic form factors extracted using
unpolarized and polarized scattering data is believed to be a consequence of
two-photon exchange (TPE) effects. However, the calculations of TPE corrections
have significant model dependence, and there is limited direct experimental
evidence for such corrections. We present the results of a new experimental
technique for making direct comparisons, which has the potential to
make precise measurements over a broad range in and scattering angles. We
use the Jefferson Lab electron beam and the Hall B photon tagger to generate a
clean but untagged photon beam. The photon beam impinges on a converter foil to
generate a mixed beam of electrons, positrons, and photons. A chicane is used
to separate and recombine the electron and positron beams while the photon beam
is stopped by a photon blocker. This provides a combined electron and positron
beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen
target. The large acceptance CLAS detector is used to identify and reconstruct
elastic scattering events, determining both the initial lepton energy and the
sign of the scattered lepton. The data were collected in two days with a
primary electron beam energy of only 3.3 GeV, limiting the data from this run
to smaller values of and scattering angle. Nonetheless, this measurement
yields a data sample for with statistics comparable to those of the
best previous measurements. We have shown that we can cleanly identify elastic
scattering events and correct for the difference in acceptance for electron and
positron scattering. The final ratio of positron to electron scattering:
for GeV and
- …