967 research outputs found
Prospections paléolithiques et perspectives technologiques pour redéfinir le hoabinhien du Nord de la Thaïlande (campagnes 2002-2005)
Recommendations for dealing with waste contaminated with Ebola virus: a Hazard Analysis of Critical Control Points approach
Objective To assess, within communities experiencing Ebola virus outbreaks, the risks associated with the disposal of human waste and to generate recommendations for mitigating such risks. Methods A team with expertise in the Hazard Analysis of Critical Control Points framework identified waste products from the care of individuals with Ebola virus disease and constructed, tested and confirmed flow diagrams showing the creation of such products. After listing potential hazards associated with each step in each flow diagram, the team conducted a hazard analysis, determined critical control points and made recommendations to mitigate the transmission risks at each control point. Findings The collection, transportation, cleaning and shared use of blood-soiled fomites and the shared use of latrines contaminated with blood or bloodied faeces appeared to be associated with particularly high levels of risk of Ebola virus transmission. More moderate levels of risk were associated with the collection and transportation of material contaminated with bodily fluids other than blood, shared use of latrines soiled with such fluids, the cleaning and shared use of fomites soiled with such fluids, and the contamination of the environment during the collection and transportation of blood-contaminated waste. Conclusion The risk of the waste-related transmission of Ebola virus could be reduced by the use of full personal protective equipment, appropriate hand hygiene and an appropriate disinfectant after careful cleaning. Use of the Hazard Analysis of Critical Control Points framework could facilitate rapid responses to outbreaks of emerging infectious disease
XUV digital in-line holography using high-order harmonics
A step towards a successful implementation of timeresolved digital in-line
holography with extreme ultraviolet radiation is presented. Ultrashort XUV
pulses are produced as high-order harmonics of a femtosecond laser and a
Schwarzschild objective is used to focus harmonic radiation at 38 nm and to
produce a strongly divergent reference beam for holographic recording.
Experimental holograms of thin wires are recorded and the objects
reconstructed. Descriptions of the simulation and reconstruction theory and
algorithms are also given. Spatial resolution of few hundreds of nm is
potentially achievable, and micrometer resolution range is demonstrated.Comment: 8 pages, 8 figure
A proposal for multi-tens of GW fully coherent femtosecond soft X-ray lasers
X-ray free-electron lasers1,2 delivering up to 131013 coherent photons in femtosecond pulses are bringing about a revolution in X-ray science3?5. However, some plasma-based soft X-ray lasers6 are attractive because they spontaneously emit an even higher number of photons (131015), but these are emitted in incoherent and long (hundreds of picoseconds) pulses7 as a consequence of the amplification of stochastic incoherent self-emission. Previous experimental attempts to seed such amplifiers with coherent femtosecond soft X-rays resulted in as yet unexplained weak amplification of the seed and strong amplification of incoherent spontaneous emission8. Using a time-dependent Maxwell?Bloch model describing the amplification of both coherent and incoherent soft X-rays in plasma, we explain the observed inefficiency and propose a new amplification scheme based on the seeding of stretched high harmonics using a transposition of chirped pulse amplification to soft X-rays. This scheme is able to deliver 531014 fully coherent soft X-ray photons in 200 fs pulses and with a peak power of 20 GW
Cure of Helicobacter pylori infection in patients with reflux oesophagitis treated with long term omeprazole reverses gastritis without exacerbation of reflux disease: results of a randomised controlled trial
BACKGROUND: Helicobacter pylori gastritis may progress to glandular
atrophy and intestinal metaplasia, conditions that predispose to gastric
cancer. Profound suppression of gastric acid is associated with increased
severity of H pylori gastritis. This prospective randomised study aimed to
investigate whether H pylori eradication can influence gastritis and its
sequelae during long term omeprazole therapy for gastro-oesophageal reflux
disease (GORD). METHODS: A total of 231 H pylori positive GORD patients
who had been treated for > or =12 months with omeprazole maintenance
therapy (OM) were randomised to either continuation of OM (OM only; n =
120) or OM plus a one week course of omeprazole, amoxycillin, and
clarithromycin (OM triple; n = 111). Endoscopy with standardised biopsy
sampling as well as symptom evaluation were performed at baseline and
after one and two years. Gastritis was assessed according to the Sydney
classification system for activity, inflammation, atrophy, intestinal
metaplasia, and H pylori density. RESULTS: Corpus gastritis activity at
entry was moderate or severe in 50% and 55% of the OM only and OM triple
groups, respectively. In the OM triple group, H pylori was eradicated in
90 (88%) patients, and activity and inflammation decreased substantially
in both the antrum and corpus (p<0.001, baseline v two years). Atrophic
gastritis also improved in the corpus (p<0.001) but not in the antrum. In
the 83 OM only patients with continuing infection, there was no change in
antral and corpus gastritis activity or atrophy, but inflammation
increased (p<0.01). H pylori eradication did not alter the dose of
omeprazole required, or reflux symptoms. CONCLUSIONS: Most H pylori
positive GORD patients have a corpus predominant pangastritis during
omeprazole maintenance therapy. Eradication of H pylori eliminates gastric
mucosal inflammation and induces regression of corpus glandular atrophy. H
pylori eradication did not worsen reflux disease or lead to a need for
increased omeprazole maintenance dose. We therefore recommend eradication
of H pylori in GORD patients receiving long term acid suppression
Tameness of pseudovariety joins involving R
2000 Mathematics Subject Classification: 20M07 (primary); 20M05, 20M35, 68Q70 (secondary).In this paper, we establish several decidability results for pseudovariety joins of the form VvW, where V is a subpseudovariety of J or the pseudovariety R. Here, J (resp. R) denotes the pseudovariety of all J-trivial (resp. R-trivial) semigroups. In particular, we show that the pseudovariety VvW is (completely) kappa-tame when V is a subpseudovariety of J with decidable kappa-word problem and W is (completely) kappa-tame. Moreover, if W is a kappa-tame pseudovariety which satisfies the pseudoidentity x_1...x_ry^{\omega+1}zt^\omega = x_1... x_ryzt^\omega, then we
prove that RvW is also kappa-tame.
In particular the joins RvAb, RvG, RvOCR,
and RvCR are decidable.União Europeia (UE). Fundo Europeu de Desenvolvimento Regional (FEDER) - POCTI/32817/MAT/2000.International Association for the Promotion of Co-operation with Scientists from the New Independent States (NIS) of the Former Soviet Union (INTAS) - project 99-1224.Fundação para a Ciência e a Tecnologia (FCT)
Modeling of Viscous Shock Tube Using ES-BGK Model Kinetic Equations
The viscous effects on unsteady shock wave propagation are investigated by numerical solution of the Boltzmann model kinetic equations. The kinetic equations are solved for two unsteady non-equilibrium flow problems, namely, the one-dimensional Riemann problem and a two-dimensional viscous shock-tube. The numerical method comprises the discrete velocity method in the velocity space and the finite volume discretization in physical space using various flux schemes. The discrete version of H-theorem is applied for analysis of accuracy of the numerical solution as well as of the onset of non-equilibrium. Simulations show that the maximum entropy generation rate in viscous shock tube occurs in the boundary layer / shock wave interaction region. The entropy generation rate is used to determine the time-variation of the speed of propagation of shock, contact discontinuity and rarefaction waves
The role of valuation and bargaining in optimising transboundary watercourse treaty regimes
In the face of water scarcity, growing water demands, population increase, ecosystem degradation, climate change, and so on transboundary watercourse states inevitably have to make difficult decisions on how finite quantities of water are distributed. Such waters, and their associated ecosystem services, offer multiple benefits. Valuation and bargaining can play a key role in the sharing of these ecosystems services and their associated benefits across sovereign borders. Ecosystem services in transboundary watercourses essentially constitute a portfolio of assets. Whilst challenging, their commodification, which creates property rights, supports trading. Such trading offers a means by which to resolve conflicts over competing uses and allows states to optimise their ‘portfolios’. However, despite this potential, adoption of appropriate treaty frameworks that might facilitate a market-based approach to the discovery and allocation of water-related ecosystem services at the transboundary level remains both a challenge, and a topic worthy of further study. Drawing upon concepts in law and economics, this paper therefore seeks to advance the study of how treaty frameworks might be developed in a way that supports such a market-based approach to ecosystem services and transboundary waters
Determinants of regurgitant volume in mitral regurgitation: contrasting effect of similar effective regurgitant orifice area in functional and organic mitral regurgitation
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