385 research outputs found
Yellow fever in Asia - a risk analysis
Background There is concern about the risk of yellow fever (YF) establishment in Asia, owing to rising numbers of urban outbreaks in endemic countries and globalisation. Following an outbreak in Angola in 2016, YF cases were introduced into China. Prior to this, YF had never been recorded in Asia, despite climatic suitability and the presence of mosquitoes. An outbreak in Asia could result in widespread fatalities and huge economic impact. Therefore, quantifying the potential risk of YF outbreaks in Asia is a public health priority. Methods Using international flight data and YF incidence estimates from 2016, we quantified the risk of YF introduction via air travel into Asia. In locations with evidence of a competent mosquito population, the potential for autochthonous YF transmission was estimated using a temperature-dependent model of the reproduction number and a branching process model assuming a negative binomial distribution. Results In total, 25 cities across Asia were estimated to be at risk of receiving at least one YF viraemic traveller during 2016. At their average temperatures, we estimated the probability of autochthonous transmission to be <50% in all cities, which was primarily due to the limited number of estimated introductions that year. Conclusion Despite the rise in air travel, we found low support for travel patterns between YF endemic countries and Asia resulting in autochthonous transmission during 2016. This supports the historic absence of YF in Asia and suggests it could be due to a limited number of introductions in previous years. Future increases in travel volumes or YF incidence can increase the number of introductions and the risk of autochthonous transmission. Given the high proportion of asymptomatic or mild infections and the challenges of YF surveillance, our model can be used to estimate the introduction and outbreak risk and can provide useful information to surveillance systems
Performance, combustion and emissions of a diesel engine operated with reformed EGR. Comparison of diesel and GTL fuelling
This is the post-print version of the final paper published in Fuel. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2008 Elsevier B.V.In this work, the effects of a standard ultra-low sulphur diesel (ULSD) fuel and a new, ultra-clean synthetic GTL (gas-to-liquid) fuel on the performance, combustion and emissions of a single-cylinder, direct injection, diesel engine were studied under different operating conditions with addition of simulated reformer product gas, referred to as reformed EGR (REGR). For this purpose various levels of REGR of two different compositions were tested. Tests with standard EGR were also carried out for comparison. Experiments were performed at four steady state operating conditions and the brake thermal efficiency, combustion process and engine emission data are presented and discussed. In general, GTL fuel resulted in a higher brake thermal efficiency compared to ULSD but the differences depended on the engine condition and EGR/REGR level and composition. The combustion pattern was significantly modified when the REGR level was increased. Although the extent of the effects of REGR on emissions depended on the engine load, it can be generally concluded that an optimal combination of GTL and REGR significantly improved both NOx and smoke emissions. In some cases, NOx and smoke emission reductions of 75% and 60%, respectively, were achieved compared to operation with ULSD without REGR. This offers a great potential for engine manufacturers to meet the requirements of future emission regulations.Shell Global Solutions UK, the Government of Castilla-La Mancha (Spain) and the Royal Thai Government
Order parameter symmetry in ferromagnetic superconductors
We analyze the symmetry and the nodal structure of the superconducting order
parameter in a cubic ferromagnet, such as ZrZn. We demonstrate how the
order parameter symmetry evolves when the electromagnetic interaction of the
conduction electrons with the internal magnetic induction and the spin-orbit
coupling are taken into account. These interactions break the cubic symmetry
and lift the degeneracy of the order parameter. It is shown that the order
parameter which appears immediately below the critical temperature has two
components, and its symmetry is described by {\em co-representations} of the
magnetic point groups. This allows us to make predictions about the location of
the gap nodes.Comment: 12 pages, ReVTeX, submitted to PR
Possible symmetries of the superconducting order parameter in a hexagonal ferromagnet
We study the order parameter symmetry in a hexagonal crystal with co-existing
superconductivity and ferromagnetism. An experimental example is provided by
carbon-based materials, such as graphite-sulfur composites, in which an
evidence of such co-existence has been recently discovered. The presence of a
non-zero magnetization in the normal phase brings about considerable changes in
the symmetry classification of superconducting states, compared to the
non-magnetic case.Comment: 4 pages, REVTe
Animals can assign novel odours to a known category
The ability to identify a novel stimulus as a member of a known category allows an organism torespond appropriately towards it. Categorisation is thus a fundamental component of cognition andan essential tool for processing and responding to unknown stimuli. Therefore, one might expectto observe it throughout the animal kingdom and across sensory domains. There is much evidenceof visual categorisation in non-human animals, but we currently know little about this process inother modalities. In this experiment, we investigated categorisation in the olfactory domain. Dogswere trained to discriminate between 40 odours; the presence or absence of accelerants formed thecategorical rule. Those in the experimental group were rewarded for responding to substrates withaccelerants (either burnt or un-burnt) and inhibit responses to the same substrates (either burnt or unburnt)without accelerants (S+ counterbalanced). The pseudocategory control group was trained onthe same stimuli without the categorical rule. The experimental group learned the discrimination andanimals were able to generalise to novel stimuli from the same category. None of the control animalswere able to learn the discrimination within the maximum number of trials. This study provides the firstevidence that non-human animals can learn to categorise non-biologically relevant odour information
Importance of Correlation Effects on Magnetic Anisotropy in Fe and Ni
We calculate magnetic anisotropy energy of Fe and Ni by taking into account
the effects of strong electronic correlations, spin-orbit coupling, and
non-collinearity of intra-atomic magnetization. The LDA+U method is used and
its equivalence to dynamical mean-field theory in the static limit is
emphasized. Both experimental magnitude of MAE and direction of magnetization
are predicted correctly near U=4 eV for Ni and U=3.5 eV for Fe. Correlations
modify one-electron spectra which are now in better agreement with experiments.Comment: 4 pages, 2 figure
Spatial Correlation of Conduction Electrons in Metal with Complicated Geometry Of The Fermi Surface
The "density-density" correlation function of conduction electrons in metal
is investigated. It is shown, that the asymptotic behaviour of the CF depends
on the shape and the local geometry of the Fermi surface. In particular, the
exponent of power law which describes the damping of Friedel oscillations at
large r (-4 for an isotropic Fermi gas) is determined by local geometry of the
FS. The applications of the obtained results to calculations of the CF in a
metal near the electron topological transition and of the RKKY exchange
integral are considered as well.Comment: 12 pages, LaTeX, 5 figures upon request (to appear in J.Phys.:CM,
1993
Progressive age-associated activation of JNK associates with conduction disruption in the aged atrium.
Connexin43 (Cx43) is critical for maintaining electrical conduction across atrial muscle. During progressive aging cardiac conduction slows and becomes susceptible to disruption, predisposing to arrhythmias. Changes in Cx43 protein expression, or its phosphorylation status, can instigate changes in the conduction of the cardiac action potential. Our study investigated whether increased levels of activated c-jun N-terminal kinase (JNK) is the mechanism responsible for the decline of Cx43 protein and intercellular communication during progressive aging. We examined right atrial muscle from guinea pigs between 1 day and 38 months of age. The area of the intercalated disc increased with age concurrent with a 75% decline in total C43 protein expression and spatial re-organisation of the remaining protein. An age-dependent increase in activated-JNK correlated with a rise in phosphorylated Cx43. The data also correlated with slowing of the action potential conduction velocity across the right atria from 0.38±0.01 m/s at 1 month of age to 0.30±0.01 m/s at 38 months of age. The JNK activator anisomycin increased levels of activated JNK in myocytes and reduced Cx43 protein expression paralleling the aging effect The JNK inhibitor SP600125, was found to eradicate almost all trace of Cx43 protein from the intercalating discs. We conclude that in vivo activation of JNK increases with age leading to the loss of Cx43 protein from atrial myocytes. This progressive loss results in impaired conduction and is likely to contribute to the increasing risk of atrial arrhythmias with advancing age
The role of emotion in patient safety : Are we brave enough to scratch beneath the surface?
Healthcare professionals work in emotionally charged settings; yet, little is known about the role of emotion in ensuring safe patient care. This article presents current knowledge in this field, drawing upon psychological approaches and evidence from clinical settings.We explore the emotions that health professionals experience in relation to making a medical error and describe the impact on healthcare professionals and on their professional and patient relationships. We also explore how positive and negative emotions can contribute to clinical decision making and affect responses to clinical situations. Evidence to date suggests that emotion plays an integral role in patient safety. Implications for training, practice and research are discussed in addition to strategies to facilitate health services to understand and respond to the influence of emotion in clinical practice
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