1,606 research outputs found
Antibiotic susceptibilities of Haemophilus influenzae in central Scotland
ObjectiveTo ascertain the incidence of antibiotic resistance in Haemophilus influenzae in central Scotland and the β-lactamases produced by these isolates.MethodsA total of 213 H. influenzae isolates from four medical lefts in Scotland [Aberdeen (n = 58), Edinburgh (n = 55), Glasgow (n = 64) and Dundee (n = 36)] were tested for susceptibility to a range of antimicrobials including β-lactams, β-lactam/β-lactamase-inhibitor combinations, and a representative 4-quinolone, antifolate and macrolide. Susceptibility testing of the β-lactam/β-lactamase-inhibitor combination amoxicillin plus clavulanic acid was conducted at both 2:1 and 4:1 ratios and with clavulanic acid fixed at a concentration of 2 mg/L. Each strain was further investigated for the presence of β-lactamase activity.ResultsAlthough the incidence of resistance to amoxicillin was 15%, in the presence of clavulanic acid, this resistance was reduced to 4.2%, 5.6% and 4.2% with the 2:1 ratio, 4:1 ratio and 2 mg/L fixed concentration, respectively. Sixteen percent of the isolates demonstrated immediate β-lactamase production. Isoelectric focusing showed that 77.4%, 16.1% and 6.5% of the β-lactamase-positive strains were found to contain TEM-1, VAT-1 and both TEM-1 and VAT-1 β-lactamases, respectively. A further 29% of the strains were recognized as being β-lactamase-positive after prolonged incubation with nitrocephin.ConclusionsThis study suggests that current testing for β-lactamases may underestimate the prevalence of β-lactamase production in H. influenzae
Progressive internal gravity waves with bounded upper surface climbing a triangular obstacle
In this paper we discuss a theoretical model for the interfacial profiles of
progressive non-linear waves which result from introducing a triangular
obstacle, of finite height, attached to the bottom below the flow of a
stratified, ideal, two layer fluid, bounded from above by a rigid boundary. The
derived equations are solved by using a nonlinear perturbation method. The
dependence of the interfacial profile on the triangular obstacle size, as well
as its dependence on some flow parameters, such as the ratios of depths and
densities of the two fluids, have been studied
A Triassic to Cretaceous Sundaland–Pacific subduction margin in West Sarawak, Borneo
Metamorphic rocks in West Sarawak are poorly exposed and studied. They were previously assumed to be pre-Carboniferous basement but had never been dated. New 40Ar/39Ar ages from white mica in quartz-mica schists reveal metamorphism between c. 216 to 220 Ma. The metamorphic rocks are associated with Triassic acid and basic igneous rocks, which indicate widespread magmatism. New U-Pb dating of zircons from the Jagoi Granodiorite indicates Triassic magmatism at c. 208 Ma and c. 240 Ma. U-Pb dating of zircons from volcaniclastic sediments of the Sadong and Kuching Formations confirms contemporaneous volcanism. The magmatic activity is interpreted to represent a Triassic subduction margin in westernmost West Sarawak with sediments deposited in a forearc basin derived from the magmatic arc at the Sundaland–Pacific margin. West Sarawak and NW Kalimantan are underlain by continental crust that was already part of Sundaland or accreted to Sundaland in the Triassic.
One metabasite sample, also previously assumed to be pre-Carboniferous basement, yielded Early Cretaceous 40Ar/39Ar ages. They are interpreted to indicate resumption of subduction which led to deposition of volcaniclastic sediments and widespread magmatism. U-Pb ages from detrital zircons in the Cretaceous Pedawan Formation are similar to those from the Schwaner granites of NW Kalimantan, and the Pedawan Formation is interpreted as part of a Cretaceous forearc basin containing material eroded from a magmatic arc that extended from Vietnam to west Borneo. The youngest U-Pb ages from zircons in a tuff layer from the uppermost part of the Pedawan Formation indicate that volcanic activity continued until c. 86 to 88 Ma when subduction terminated
The atmospheric implications of radiation belt remediation
High altitude nuclear explosions (HANEs) and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR). Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections
A Bayesian technique for improving the sensitivity of the atmospheric neutrino L/E analysis
This paper outlines a method for improving the precision of atmospheric
neutrino oscillation measurements. One experimental signature for these
oscillations is an observed deficit in the rate of charged-current
interactions with an oscillatory dependence on , where
is the neutrino propagation distance, and is the neutrino
energy. For contained-vertex atmospheric neutrino interactions, the
resolution varies significantly from event to event. The
precision of the oscillation measurement can be improved by incorporating
information on resolution into the oscillation analysis. In
the analysis presented here, a Bayesian technique is used to estimate the
resolution of observed atmospheric neutrinos on an
event-by-event basis. By separating the events into bins of
resolution in the oscillation analysis, a significant improvement in
oscillation sensitivity can be achieved.Comment: 12 pages, 7 figures, submitted to Nucl. Instrum. Methods A,
accompanies arXiv:1208.2915 [hep-ex
Preweaning Processing Anthelmintic Treatment and Post weaning Effects of Sulfamethazine Based Medications on Performance Traits and Oocyst Shedding in Weaned Calves
Two trials were conducted to evaluate antibiotic therapies for feeder calves originating in western South Dakota. In Trial 1, processing-anthelmintic treatment 28 days before weaning reduced ranch gains and provided no advantage in feedlot gains when calves were reprocessed. Processing included deworming, grubicide treatment, implanting and vaccination. Sulfamethazine medication caused transient improvements in feedlot performance during the feedlot receiving period in both trials. Supertherapeutic treatment with AS 700 offered no advantage in feedlot performance over therapeutic feeding in these calves. Sulfamethazine exposure suppressed coccidia oocyst shedding and appears to be an effective means of controlling coccidiosis and shipping fever complex for newly received calves
Neutrino mean free paths in spin-polarized neutron Fermi liquids
Neutrino mean free paths in magnetized neutron matter are calculated using
the Hartree-Fock approximation with effective Skyrme and Gogny forces in the
framework of the Landau Fermi Liquid Theory. It is shown that describing
nuclear interaction with Skyrme forces and for magnetic field strengths
, the neutrino mean free paths stay almost unchanged
at intermediate densities but they largely increase at high densities when they
are compared to the field-free case results. However the description with Gogny
forces differs from the previous and mean free paths stay almonst unchanged or
decrease at densities . This different behaviour can be explained
due to the combination of common mild variation of the Landau parameters with
both types of forces and the values of the nucleon effective mass and induced
magnetization of matter under presence of a strong magnetic field as described
with the two parametrizations of the nuclear interaction.Comment: 9 pages, 3 figure
Prospects for the Measurement of the Higgs Yukawa Couplings to b and c quarks, and muons at CLIC
The investigation of the properties of the Higgs boson, especially a test of
the predicted linear dependence of the branching ratios on the mass of the
final state is going to be an integral part of the physics program at colliders
at the energy frontier for the foreseeable future. The large Higgs boson
production cross section at a 3TeV CLIC machine allows for a precision
measurement of the Higgs branching ratios. The cross section times branching
ratio of the decays H->bb, H->cc and H->{\mu}{\mu} of a Standard Model Higgs
boson with a mass of 120 GeV can be measured with a statistical uncertainty of
0.23%, 3.1% and 15%, respectively, assuming an integrated luminosity of 2 ab-1.Comment: 6 pages, 4 figure
Evaluation of measurement accuracies of the Higgs boson branching fractions in the International Linear Collider
Precise measurement of Higgs boson couplings is an important task for
International Linear Collider (ILC) experiments and will facilitate the
understanding of the particle mass generation mechanism.
In this study, the measurement accuracies of the Higgs boson branching
fractions to the and quarks and gluons, , were evaluated with the full International Large
Detector model (\texttt{ILD\_00}) for the Higgs mass of 120 GeV at the
center-of-mass (CM) energies of 250 and 350 GeV using neutrino, hadronic and
leptonic channels and assuming an integrated luminosity of ,
and an electron (positron) beam polarization of -80% (+30%).
We obtained the following measurement accuracies of the Higgs cross section
times branching fraction () for decay
of the Higgs into , , and ; as 1.0%, 6.9%, and 8.5% at
a CM energy of 250 GeV and 1.0%, 6.2%, and 7.3% at 350 GeV, respectively.
After the measurement accuracy of the cross section ()
was corrected using the results of studies at 250 GeV and their extrapolation
to 350 GeV, the derived measurement accuracies of the branching fractions
() to , , and gg were 2.7%, 7.3%, and 8.9% at
a CM energy of 250 GeV and 3.6%, 7.2%, and 8.1% at 350 GeV, respectively.Comment: 15 pages, 6 figure
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