45 research outputs found
Transmission of low-energy scalar waves through a traversable wormhole
We study the scattering of low-energy massless and massive minimally coupled
scalar fields by an asymptotically flat traversable wormhole. We provide a
comprehensive treatment of this problem offering analytic expressions for the
transmission and reflection amplitudes of the corresponding effective potential
and the absorption cross section of the wormhole. Our results, which are based
on a recently developed dynamical formulation of time-independent scattering
theory, apply to a large class of wormhole spacetimes including a wormhole with
a sharp transition, the Ellis wormhole, and a family of its generalizations.Comment: 21 pages, 3 figures, references added, accepted for publication in
European Physical Journal
Integrating Pd-doped perovskite catalysts with ceramic hollow fibre substrate for efficient CO oxidation
Doping Pd into perovskite catalysts helps to reduce light-off temperatures, improve thermal-chemical stability and lowered catalyst cost by decreasing Platinum Group Metals (PGMs). In this study, LaFe0.7Mn0.225Pd0.075O3 (LFMPO) and LaFe0.7Co0.225Pd0.075O3 (LFCPO) were synthesised, characterized and evaluated for catalytic treatment of automotive emissions, using CO oxidation as the model reaction. Such catalysts were further incorporated inside micro-structured ceramic hollow fibre substrates, and compared with a packed bed configuration by light-off temperatures. Performance evaluations suggest that, LFMPO deposited inside the hollow fibre substrate could be light up at 232â°C, which is 10â°C lower than a packed-bed counterpart with the same amount of catalyst (5âmg) and GHSV of âŒ5300 hâ1. While excessive incorporation of the catalyst (10âmg) generates significantly higher transfer resistance, which impairs catalytic performance of hollow fibre reactors, with CO conversion per gram of catalyst reduced from 0.01âmol gâ1 to 0.0051âmol gâ1
The First Iranian Record of Suncus Murinus
199 human serum samples were examined for the presence of Myxovirus Parainfluenza 3 (MPI 3) haemagglutination inhibition (HI) antibodies. or tbe total male sera, 75% and female 70.52% had HI antibody titers of t:32 or greater. The percentage of positive samples increased according to the age grouping of the human beings. These results indicate that MPI 3 virus infection is widespread among the human population in Iran. and it may be considered as one of the causes of respiratory illnesses in children and adults
Calodium hepaticum (syn. Capillaria hepatica) in captive rodents in a zoological garden
Calodium hepaticum infection was diagnosed in the Bristol Zoo Gardens in 13 captive rodents of four species that died or were humanely killed over a 40-month period. Of these infected animals, nine were black-tailed prairie dogs (Cynomus ludovicianus), representing 45% of the members of this species examined during the study. A wild rat (Rallus norvegicus) found dead in an enclosure was also infected. To date few cases of C. hepaticum infection have been reported in the UK. The number of cases diagnosed in this urban zoo may be explained by the potentially high prevalence of infection in urban rat populations and increased risk of exposure of zoo animals kept in enclosures to which rats have access. As C. hepaticum is potentially zoonotic, members of staff in zoos should be careful to avoid soil-to-mouth contact, particularly in prairie dog enclosures. (c) 2005 Elsevier Ltd. All rights reserved