18,701 research outputs found
Threshold Effects in Slepton-Pair Production at the LHC
We present a study of threshold resummation effects for slepton pair
production at the Large Hadron Collider (LHC). After confirming the known NLO
QCD corrections and generalizing the NLO SUSY-QCD corrections to the case of
mixing squarks in the virtual loop contributions, we employ the Mellin N-space
resummation formalism to compute logarithmically enhanced soft-gluon terms to
all perturbative orders.Comment: 3 pages, 1 figure, presented at HEP 2007 (Manchester, July 2007
Slip casting and extruding shapes of rhemium with metal oxide additives. Part 2: Development of grain stabilized rhenium parts for resistojets
The adaptation of the powdered particle process used for pure metal oxides to the coprocessing of rhenium oxides suitable to produce pure miniature resistojet hardware has been successful. Both slip casting and extrusion processes were used. The metal oxide ZrO2 was stabilized into the cubic phase with Y2O3, for use as a potentially grain stabilizing additive to rhenium. Straight meter long tubing in two sizes are reported. Tubing suitable for resistojet ohmic heater use of fully fired dimensions of nominally 3.8 mm o.d. x 2.2 mm i.d.. and 1.26 mm o.d. x .45 mm i.d. with 0, 0.5, 1.0 and 5.0% zirconia additives were produced for further study. Photomicrographs of these are discussed. The addition of the metal oxide zirconia to rhenium resulted in more dense and less porous parts. The additions of phase stabilized zirconia most likely act as a sintering aid. Tubes of varying diameter were slip cast which were representative of miniature pressure cases
Slip casting and extruding shapes of rhenium with metal oxide additives. 1: Feasibility demonstration
The feasibility of fabricating small rhenium parts with metal oxide additives by means of slip casting and extrusion techniques is described. The metal oxides, ZrO2 and HfO2 were stabilized into the cubic phase with Y2O3. Additions of metal oxide to the rhenium of up to 15 weight percent were used. Tubes of 17 mm diameter with 0.5 mm walls were slip cast by adapting current ceramic oxide techniques. A complete cast double conical nozzle demonstrated the ability to meet shapes and tolerances. Extrusion of meter long tubing lengths of 3.9 mm o.d. x 2.3 mm i.d. final dimension is documented. Sintering schedules are presented to produce better than 95% of theoretical density parts. Finished machining was found possible were requried by electric discharge machining and diamond grinding
Exploring the acceptability of two self-sampling devices for human papillomavirus testing in the cervical screening context: a qualitative study of Muslim women in London
Objectives We explored Muslim women's attitudes to self-sampling for human papillomavirus (HPV) in the context of cervical cancer screening and their responses to two self-sampling devices.Setting A Muslim community centre in north-east London.Methods Following a talk given on the subject of cervical cancer and HPV at the community centre, 28 women were recruited to take part in three focus group discussions. The discussion covered cervical screening, self-sampling and HPV testing. Women were also asked for their responses to a swab self-sampling kit and a cervico-vaginal lavage device. Discussions were recorded and transcribed verbatim and the qualitative data were analysed using Framework Analysis.Results Participants were generally positive about cervical screening but acknowledged that some women in their community were reluctant to offend because of embarrassment, language difficulties, fear or because they were unmarried and did not want to communicate implicit messages about being sexually active. Self-sampling met a mixed response - women were concerned about not doing the test correctly, but thought that it might overcome barriers to screening for some women. HPV testing itself was thought to raise potentially difficult issues relating to trust and fidelity within marriages. Although most women said they would prefer to continue to have screening by a health professional, if they were to perform self-sampling, there was overwhelming preference for the swab over the lavage kit.Conclusions There was limited enthusiasm for self-sampling in this group of Muslim women who had mostly attended for cervical screening, but a clear preference for a swab rather than a cervico-vaginal lavage
Raman gain against a background of non-thermal ion fluctuations in a plasma
A complex stimulated Raman scattering event against a background of non-thermal ion acoustic waves in an inhomogeneous plasma is described. We obtain analytic forms for the Raman gain due to a five-wave interaction consisting of conventional three-wave Raman scattering followed by the decay of the Raman Langmuir wave into a second Langmuir wave (or a second scattered light wave) and an ion acoustic wave. Very modest levels of ion waves produce a. significant effect on Raman convective gain. A combination of plasma inhomogeneity and suprathermal ion fluctuations may offer a means for the control of Raman gain
A comment on "Amplification of endpoint structure for new particle mass measurement at the LHC"
We present a comment on the kinematic variable recently proposed in
"Amplification of endpoint structure for new particle mass measurement at the
LHC". The variable is designed to be applied to models such as R-parity
conserving Supersymmetry (SUSY) when there is pair production of new heavy
particles each of which decays to a single massless visible and a massive
invisible component. It was proposed in "Amplification of endpoint structure
for new particle mass measurement at the LHC" that a measurement of the peak of
the distribution could be used to precisely constrain the masses of
the SUSY particles. We show that when Standard Model backgrounds are included
in simulations, the sensitivity of the variable to the SUSY particle
masses is more seriously impacted for than for other previously
proposed variables.Comment: 5 page
Nonstandard order parameters and the origin of CP violation
The consideration of chirality-preserving 2-fermion order parameters may shed
new light on the strong CP problem and the breakdown of flavor symmetries. We
describe two situations, one having the standard KM picture for weak CP
violation and another having new sources of weak CP violation.Comment: 12 pages, no figure
Risk factors for failure of outpatient parenteral antibiotic therapy (OPAT) in infective endocarditis
Objectives:
To identify risk factors for failure of outpatient antibiotic therapy (OPAT) in infective endocarditis (IE).
Patients and methods:
We identified IE cases managed at a single centre over 12 years from a prospectively maintained database. âOPAT failureâ was defined as unplanned readmission or antibiotic switch due to adverse drug reaction or antibiotic resistance. We analysed patient and disease-related risk factors for OPAT failure by univariate and multivariate logistic regression. We also retrospectively collected follow-up data on adverse disease outcome (defined as IE-related death or relapse) and performed KaplanâMeier survival analysis up to 36 months following OPAT.
Results:
We identified 80 episodes of OPAT in IE. Failure occurred in 25/80 episodes (31.3%). On multivariate analysis, cardiac or renal failure [pooled OR 7.39 (95% CI 1.84â29.66), Pâ=â0.005] and teicoplanin therapy [OR 8.69 (95% CI 2.01â37.47), Pâ=â0.004] were independently associated with increased OPAT failure. OPAT failure with teicoplanin occurred despite therapeutic plasma levels. OPAT failure predicted adverse disease outcome up to 36 months (Pâ=â0.016 log-rank test).
Conclusions:
These data caution against selecting patients with endocarditis for OPAT in the presence of cardiac or renal failure and suggest teicoplanin therapy may be associated with suboptimal OPAT outcomes. Alternative regimens to teicoplanin in the OPAT setting should be further investigated
Simulating Impacts of Extreme Weather Events on Urban Transport Infrastructure in the UK
Urban areas face many risks from future climate change and their infrastructure will be placed under more pressure
due to changes in climate extremes. Using the Tyndall Centre Urban Integrated Assessment Framework, this paper
describes a methodology used to assess the impacts of future climate extremes on transport infrastructure in
London. Utilising high-resolution projections for future climate in the UK, alongside stochastic weather generators
for downscaling, urban temperature and flooding models are used to provide information on the likelihood of future
extremes. These are then coupled with spatial network models of urban transport infrastructure and, using thresholds
to define the point at which systems cease to function normally, disruption to the networks can be simulated.
Results are shown for both extreme heat and urban surface water flooding events and the impacts on the travelling
population, in terms of both disruption time and monetary cost
Visualisation Tools for Multi-Perspective, Cross-Sector, Long-Term Infrastructure Performance Evaluation
Across different infrastructure sectors there are systems that help to monitor the current and near-future operation
and performance of a particular system. Whilst Supervisory Control and Data Acquisition (SCADA) systems are critical
to maintaining acceptable levels of functionality, they do not provide insights over the longer timescales across which
strategic investment decisions play out. To understand how individual or multiple, interdependent, infrastructure
sectors perform over longer timescales, capacity/demand modelling is required. However, the outputs of such
models are often a complex high-dimensionality result-set, and this complexity is further compounded when crosssector
evaluation is required. To maximise utility of such models, tools are required that can process and present
key outputs. In this paper we describe the development of prototype tools for infrastructure performance evaluation
in relation to different strategic decisions and the complex outputs generated from capacity and demand models of
five infrastructure sectors (energy, water, waste water, solid waste, transport) investigated within the UK Infrastructure
Transitions Research Consortium (ITRC). By constructing tools that expose various dimensions of the model outputs,
a user is able to take greater control over the knowledge discovery process
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