6,117 research outputs found
Diamond degradation in hadron fields
The energy dependence of the concentration of primary displacements induced
by protons and pions in diamond has been calculated in the energy range 50 MeV
- 50 GeV, in the frame of the Lindhard theory. The concentrations of primary
displacements induced by protons and pions have completely different energy
dependencies: the proton degradation is very important at low energies, and is
higher than the pion one in the whole energy range investigated, with the
exception of the delta33 resonance region. Diamond has been found,
theoretically, to be one order of magnitude more resistant to proton and pion
irradiation in respect to silicon.Comment: 7 pages, 3 figure
Origin and thermal evolution of Mars
The thermal evolution of Mars is governed by subsolidus mantle convection beneath a thick lithosphere. Models of the interior evolution are developed by parameterizing mantle convective heat transport in terms of mantle viscosity, the superadiabatic temperature rise across the mantle, and mantle heat production. Geological, geophysical, and geochemical observations of the compositon and structure of the interior and of the timing of major events in Martian evolution are used to constrain the model computations. Such evolutionary events include global differentiation, atmospheric outgassing, and the formation of the hemispherical dichotomy and Tharsis. Numerical calculations of fully three-dimensional, spherical convection in a shell the size of the Martian mantle are performed to explore plausible patterns of Martian mantel convection and to relate convective features, such as plumes, to surface features, such as Tharsis. The results from the model calculations are presented
Calculation of quasi-degenerate energy levels of two-electron ions
Accurate QED calculations of the interelectron interaction corrections for
the , two-electron configurations for ions
with nuclear charge numbers are performed within the line
profile approach. Total energies of these configurations are evaluated.
Employing the fully relativistic treatment based on the {--} coupling
scheme these energy levels become quasi-degenerate in the region . To
treat such states within the framework of QED we utilize the line profile
approach. The calculations are performed within the Coulomb gauge.Comment: 22 pages, 11 figure
QED Calculation of E1M1 and E1E2 Transition Probabilities in One-Electron Ions with Arbitrary Nuclear Charge
The quantum electrodynamical theory of the two-photon transitions in
hydrogenlike ions is presented. The emission probability for 2s1/2 -> 2E1+1s1/2
transitions is calculated and compared to the results of the previous
calculations. The emission probabilities 2p12 -> E1E2+1s1/2 and 2p1/2 ->
E1M1+1s1/2 are also calculated for the nuclear charge Z values 1-100. This is
the first calculation of the two latter probabilities. The results are given in
two different gauges.Comment: 14 pages, 4 tables, 1 figur
What are the participants’ perspectives of taking melatonin for the treatment of nocturia in Multiple Sclerosis? -a qualitative study embedded within a double blind RCT
Background: Multiple Sclerosis (MS) is a chronic neurological disorder caused by neurodegeneration within the central nervous system. It results in impaired physical, cognitive and psychological functioning and can also lead to lower urinary tract symptoms including nocturia. While clinical trials have suggested an association between nocturia and melatonin secretion, to our knowledge, no qualitative research has been conducted on the experience of taking melatonin to treat nocturia in progressive MS within a clinical trial. Methods: 17 semi-structured qualitative interviews were conducted as part of a double-blind, randomised, placebo controlled, crossover, clinical trial with consenting adults with MS. Interviews explored participants’ experiences of nocturia associated with MS and their experience of taking melatonin as a trial treatment for nocturia versus a placebo. Data was analysed using a thematic analysis. Results: Themes on the experience of nocturia revealed participants’ understandings of nocturia, the impact it had on their night and increased daily fatigue. Themes on the intervention showed perceived improvements to nocturia, sleep and energy and negative effects including lethargy, a lack of significant change and physical side effects including vivid dreams.Conclusion: This qualitative exploration revealed an association between nocturia and increased levels of fatigue during the day by those with MS. However, perspectives towards the effectiveness of melatonin as a potential treatment varied as both placebo and melatonin were perceived as having very similar effects
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