61 research outputs found
Interaction between ionic lattices and superconducting condensates
The interaction of the ionic lattice with the superconducting condensate is
treated in terms of the electrostatic force in superconductors. It is shown
that this force is similar but not identical to the force suggested by the
volume difference of the normal and superconducting states. The BCS theory
shows larger deviations than the two-fluid model.Comment: 6 pages no figure
Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds
Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period
Radiation re-solution of fission gas in non-oxide nuclear fuel
To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/journal-of-nuclear-materials.Renewed interest in fast nuclear reactors is creating a need for better understanding of fission gas bubble behavior in non-oxide fuels. Collisions between\ud
fission fragments and their subsequent cascades can knock fission gas atoms out\ud
of bubbles and back into the fuel lattice, resulting in a loss term for the bubble.\ud
By assuming these collisions can be treated as binary collisions, we calculated a\ud
re-solution parameter as a function of bubble radius. The calculations showed\ud
that there is a sharp decrease as bubble size increases until about 100 nm when\ud
the re-solution parameter stays nearly constant. The bubble size dependence\ud
may explain the large bubble size distribution found in some uranium carbide\ud
and nitride fuels. Furthermore, our model shows ion cascades created in the\ud
fuel result in many more implanted fission gas atoms than collisions directly\ud
with fission fragments. Utilization of our calculated re-solution parameter can\ud
be used to find a re-solution rate for future bubble behavior simulations
Coordination polymers utilizing N-oxide functionalised host ligands
Pyridyl functionalized host molecules are oxidized to their N-oxide analogues and form a series of coordination polymers and discrete complexes with transition metal cations. Complex {[Ag3(NMP)6(L1)2]·3(ClO4)}â where L1 = tris(isonicotinoyl-N-oxide)cyclotriguaiacylene, NMP = N-methylpyrrolidone, is a three-dimensional (3-D) 3,6-connected coordination polymer of pyrite-like (pyr) topology and features ligand unsupported argentophilic interactions, while two-dimensional (2-D) 3,6-connected coordination polymers with the rarely reported kagome dual (kgd) topology are found for [M(L1)2]2+ where M = Zn, Cd, Cu. Ligand L2 = tris(nicotinoyl-N-oxide)cyclotriguaiacylene forms a 2-D coordination polymer with 44 (sql) grid topology in complexes {[M(L2)2(DMF)2]·2ClO4·8(DMF)}â M = Cd or Cu, DMF = N,NâČ-dimethylformamide, and a double-linked chain structure in {[Co(L2)2(DMF)2]·2NO3·4(DMF)·H2O}â, and both types of structure feature hand-shake self-inclusion motifs either within or between the polymers. 2-D coordination networks with 63 (hcb) topologies are found in complexes {[M(L3)(NO3)2]·2(DMF)}â (M = Cd, Zn) and {[Cu5(L3)2Cl10(NMP)4]}â where L3 = tris(2-pyridylmethyl)cyclotriguaiacylene, while [Ag2(L3)2(NMP)4]·2(BF4)·2(NMP) has a discrete dimeric structure which again shows hand-shake hostâguest interactions supported by ÏâÏ stacking
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