42 research outputs found
Further study of the Over-Barrier Model to compute charge exchange processes
In this paper we study theoretically the process of electron capture between
one-optical-electron atoms (e.g. hydrogenlike or alkali atoms) and ions at
low-to-medium impact velocities () working on a modification
of an already developed classical In this work we present an improvement over
the Over Barrier Model (OBM) described in a recent paper [F. Sattin, Phys. Rev.
A {\bf 62}, 042711 (2000)]. We show that: i) one of the two free parameters
there introduced actually comes out consistently from the starting assumptions
underlying the model; ii) the modified model thus obtained is as much accurate
as the former one. Furthermore, we show that OBMs are able to accurately
predict some recent results of state selective electron capture, at odds with
what previously supposed.Comment: RevTeX, 7 pages, 4 eps figures. To appear in Physical Review A
(2001-september issue
A classical Over Barrier Model to compute charge exchange between ions and one-optical-electron atoms
In this paper we study theoretically the process of electron capture between
one-optical-electron atoms (e.g. hydrogenlike or alkali atoms) and ions at
low-to-medium impact velocities (v/v_e <= 1) working on a modification of an
already developed classical Over Barrier Model (OBM) [V. Ostrovsky, J. Phys. B:
At. Mol. Opt. Phys. {\bf 28} 3901 (1995)], which allows to give a
semianalytical formula for the cross sections. The model is discussed and then
applied to a number of test cases including experimental data as well as data
coming from other sophisticated numerical simulations. It is found that the
accuracy of the model, with the suggested corrections and applied to quite
different situations, is rather high.Comment: 12 pages REVTEX, 5 EPSF figures, submitted to Phys Rev
Clinical significance of serological biomarkers and neuropsychological performances in patients with temporal lobe epilepsy
<p>Abstract</p> <p>Background</p> <p>Temporal lobe epilepsy (TLE) is a common form of focal epilepsy. Serum biomarkers to predict cognitive performance in TLE patients without psychiatric comorbidities and the link with gray matter (GM) atrophy have not been fully explored.</p> <p>Methods</p> <p>Thirty-four patients with TLE and 34 sex - and age-matched controls were enrolled for standardized cognitive tests, neuroimaging studies as well as measurements of serum levels of heat shock protein 70 (HSP70), S100Ă protein (S100ĂP), neuronal specific enolase (NSE), plasma nuclear and mitochondrial DNA levels.</p> <p>Results</p> <p>Compared with the controls, the patients with TLE had poorer cognitive performances and higher HSP70 and S100ĂP levels (<it>p </it>< 0.01). The patients with higher frequencies of seizures had higher levels of HSP70, NSE and S100ĂP (<it>p </it>< 0.01). Serum HSP70 level correlated positively with duration of epilepsy (Ï = 0.413, <it>p </it>< 0.01), and inversely with memory scores in the late registration (Ï = â0.276, <it>p </it>= 0.01) and early recall score (Ï = â0.304, <it>p </it>= 0.007). Compared with the controls, gray matter atrophy in the hippocampal and parahippocampal areas, putamen, thalamus and supplementary motor areas were found in the patient group. The HSP70 levels showed an inverse correlation with hippocampal volume (R square = 0.22, <it>p </it>= 0.007) after controlling for the effect of age.</p> <p>Conclusions</p> <p>Our results suggest that serum biomarkers were predictive of higher frequencies of seizures in the TLE group. HSP70 may be considered to be a stress biomarker in patients with TLE in that it correlated inversely with memory scores and hippocampal volume. In addition, the symmetric extratemporal atrophic patterns may be related to damage of neuronal networks and epileptogenesis in TLE.</p
ACUTRI: a computer code for assessing doses to the general public due to acute tritium releases
Tritium, which is used as a fuel of a D-T burning fusion reactor, is the most important radionuclide for the safety assessment of a nuclear fusion experimental reactor such as ITER. Thus, a computer code, ACUTRI, which calculates the radiological impact of tritium released accidentally to the atmosphere, has been developed, aiming to be of use in a discussion of licensing of a fusion experimental reactor and an environmental safety evaluation method in Japan. ACUTRI calculates an individual tritium dose based on transfer models specific to tritium in the environment and ICRP dose models. In this calculation it is also possible to analyze statistically on meteorology in the same way as a conventional dose assessment method according to the meteorological guide of the Nuclear Safety Commission of Japan. A Gaussian plume model is used for calculating the atmospheric dispersion of tritium gas (HT) and/or tritiated water (HTO). The environmental pathway model in ACUTRI considers the following internal exposures: inhalation from a primary plume (HT and/or HTO) released from the facilities and inhalation from a secondary plume (HTO) reemitted from the ground following deposition of HT and HTO. This report describes an outline of the ACUTRI code, a user guide and the results of test calculation