1,682 research outputs found
Two-stage Bayesian model to evaluate the effect of air pollution on chronic respiratory diseases using drug prescriptions
Exposure to high levels of air pollutant concentration is known to be associated with respiratory problems which can translate into higher morbidity and mortality rates. The link between air pollution and population health has mainly been assessed considering air quality and hospitalisation or mortality data. However, this approach limits the analysis to individuals characterised by severe conditions. In this paper we evaluate the link between air pollution and respiratory diseases using general practice drug prescriptions for chronic respiratory diseases, which allow to draw conclusions based on the general population.
We propose a two-stage statistical approach: in the first stage we specify a space-time model to estimate the monthly NO2 concentration integrating several data sources characterised by different spatio-temporal resolution; in the second stage we link the concentration to the β2-agonists prescribed monthly by general practices in England and we model the prescription rates through a small area approach
Coherency in space of lake and river temperature and water quality records
Environmental time series observed over 100’s of monitoring locations usually possess some spatial structure in terms of common patterns throughout time, commonly described as temporal coherence. This paper will apply, develop and compare two methods for clustering time series on the basis of their patterns over time. The first approach treats the time series as functional data and applies hierarchical clustering while the second uses a state-space model based clustering approach. Both methods are developed to incorporate spatial correlation and stopping criteria are investigated to identify an appropriate number of clusters. The methods are applied to Total Organic Carbon data from river sites across Scotland
Instability of the superfluid flow as black-hole lasing effect
We show that the instability leading to the decay of the one-dimensional
superfluid flow through a penetrable barrier are due to the black-hole lasing
effect. This dynamical instability is triggered by modes resonating in an
effective cavity formed by two horizons enclosing the barrier. The location of
the horizons is set by , with being the local fluid
velocity and sound speed, respectively. We compute the critical velocity
analytically and show that it is univocally determined by the horizons
configuration. In the limit of broad barriers, the continuous spectrum at the
origin of the Hawking-like radiation and of the Landau energetic instability is
recovered.Comment: 18 pages, 3 figure
Modification of magnetic and transport properties of manganite layers in Au/La_0.67Sr_0.33MnO_3/SrTiO_3 interfaces
The effect of gold capping on magnetic and transport properties of optimally
doped manganite thin films is studied. An extraordinary suppression of
conductivity and magnetic properties occurs in epitaxial (001)
La_0.67Sr_0.33MnO_3 (LSMO) films grown on SrTiO_3 upon deposition of 2 nm of
Au: in the case of ultrathin films of LSMO (4 nm thick) the resistivity
increases by four orders of magnitude while the Curie temperature decreases by
180 K. Zero-field 55Mn nuclear magnetic resonance reveals a significant
reduction of ferromagnetic double-exchange mechanism in manganite films upon
the gold capping. We find evidence for the formation of a 1.9-nm thick magnetic
"dead-layer" at the Au/LSMO interface, associated with the creation of
interfacial non double-exchange insulating phases.Comment: 4 figure
Recent finding and new technologies in nephrolithiasis: a review of the recent literature
This review summarizes recent literature on advances regarding renal and ureteral
calculi, with particular focus in areas of recent advances in the overall field
of urolithiasis. Clinical management in everyday practice requires a complete
understanding of the issues regarding metabolic evaluation and subgrouping of
stone-forming patients, diagnostic procedures, effective treatment regime in
acute stone colic, medical expulsive therapy, and active stone removal. In this
review we focus on new perspectives in managing nephrolitihiasis and discuss
recentadvances, including medical expulsive therapy, new technologies, and
refinements of classical therapy such as shock wave lithotripsy, give a
fundamental modification of nephrolithiasis management. Overall, this field
appears to be the most promising, capable of new developments in ureterorenoscopy
and percutaneous approaches. Further improvements are expected from
robotic-assisted procedures, such as flexible robotics in ureterorenoscopy
2p3s3p, 2p3p3p, and 2p3s3s resonant Auger spectroscopy from NiO
We have investigated the behavior of the 2p3s3p, 2p3p3p, and 2p3s3s Auger lines of NiO, a model
compound in the class of strongly correlated 3d systems, while varying the photon energy across the Ni L3 and
L2 absorption edges. The experimental data are discussed in comparison with a theoretical model based on a
charge-transfer multiplet approach. When the excitation energy is below the L3 resonance, we observe the
2p3p3p and 2p3s3p peaks at a constant binding energy. This behavior is typical of nonradiative resonant
Raman scattering. If the photon energy is increased further, the 2p3p3p and 2p3s3p lines rapidly transform
into constant kinetic energy features, showing a normal Auger behavior. The transition from Raman- to
Auger-like behavior takes place for photon energies lower than the ones corresponding to excitations of the
photoelectron into ligand-hole states. This might indicate the participation of inelastic processes in the recombination
of the core hole involving energies much smaller than the NiO gap, or the possible presence of
nonlocal effects. On the high photon energy side of the L3 edge, the constant kinetic energy of the 2p3p3p
and 2p3s3p peaks is systematically larger than the one observed for an excitation well above the L2,3 edges.
We attribute this behavior to the intervention of an intermediate state of 2p^5 3d^10 character, which has very
little weight but is strongly enhanced at resonance
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