Catharanthus mosaic virus: A potyvirus from a gymnosperm, Welwitschia mirabilis

A virus from a symptomatic plant of the gymnosperm Welwitschia mirabilis Hook. growing as an ornamental plant in a domestic garden in Western Australia was inoculated to a plant of Nicotiana benthamiana where it established a systemic infection. The complete genome sequence of 9636 nucleotides was determined using high-throughput and Sanger sequencing technologies. The genome sequence shared greatest identity (83% nucleotides and 91% amino acids) with available partial sequences of catharanthus mosaic virus, indicating that the new isolate belonged to that taxon. Analysis of the phylogeny of the complete virus sequence placed it in a monotypic group in the genus Potyvirus. This is the first record of a virus from W. mirabilis, the first complete genome sequence of catharanthus mosaic virus determined, and the first record from Australia. This finding illustrates the risk to natural and managed systems posed by the international trade in live plants and propagules, which enables viruses to establish in new regions and infect new hosts

Strangeness Production and Ultrarelativistic Cascades

A two phase cascade, LUCIFER II, developed for the treatment of ultra high energy ion-ion collisions is applied to the production of strangeness at SPS energies $\sqrt{s}=17-20$. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons, including strange mesons, by separating the dynamics into two steps, a fast cascade involving only nucleons in the original colliding relativistic ions followed, after an appropriate delay, by multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy ion experiments at the CERN SPS. A byproduct, obtained here in preliminary calculations, is a description of strangeness production in the collision of massive ions.Comment: 10 pages, 5 figure

Proton-proton bremsstrahlung below and above pion-threshold: the influence of the Δ\Delta-isobar

The proton-proton bremsstrahlung is investigated within a coupled-channel model with the $\Delta$ degree of freedom. The model is consistent with the $NN$ scattering up to 1 GeV and the $\gamma N\Delta$ vertex determined in the study of pion photoproduction reactions. It is found that the $\Delta$ excitation can significantly improve the agreements with the $pp \rightarrow pp\gamma$ at $E_{lab}=280$ MeV. Predictions at $E_{lab}=550$ and $800$ MeV are presented for future experimental tests.Comment: 26 pages Revtex, 12 figures are available from the authors upon request ([email protected]

Biogeochemical processes in the active layer and permafrost of a high Arctic fjord valley

Warming of ground is causing microbial decomposition of previously frozen sedimentary organic carbon in Arctic permafrost. However, the heterogeneity of the permafrost landscape and its hydrological processes result in different biogeochemical processes across relatively small scales, with implications for predicting the timing and magnitude of permafrost carbon emissions. The biogeochemical processes of iron- and sulfate-reduction produce carbon dioxide and suppress methanogenesis. Hence, in this study, the biogeochemical processes occurring in the active layer and permafrost of a high Arctic fjord valley in Svalbard are identified from the geochemical and stable isotope analysis of aqueous and particulate fractions in sediment cores collected from ice-wedge polygons with contrasting water content. In the drier polygons, only a small concentration of organic carbon (<5.40 dry weight%) has accumulated. Sediment cores from these drier polygons have aqueous and solid phase chemistries that imply sulfide oxidation coupled to carbonate and silicate dissolution, leading to high concentrations of aqueous iron and sulfate in the pore water profiles. These results are corroborated by δ34S and δ18O values of sulfate in active layer pore waters, which indicate the oxidative weathering of sedimentary pyrite utilising either oxygen or ferric iron as oxidising agents. Conversely, in the sediments of the consistently water-saturated polygons, which contain a high content of organic carbon (up to 45 dry weight%), the formation of pyrite and siderite occurred via the reduction of iron and sulfate. δ34S and δ18O values of sulfate in active layer pore waters from these water-saturated polygons display a strong positive correlation (R2 = 0.98), supporting the importance of sulfate reduction in removing sulfate from the pore water. The significant contrast in the dominant biogeochemical processes between the water-saturated and drier polygons indicates that small-scale hydrological variability between polygons induces large differences in the concentration of organic carbon and in the cycling of iron and sulfur, with ramifications for the decomposition pathway of organic carbon in permafrost environments

Enhancing inclusivity and diversity among cathedral visitors: the Brecon Jazz Festival and psychographic segmentation

A series of previous studies concerned with the psychographic segmentation of visitors to six cathedrals across England and Wales, employing psychological type theory, reported highly similar results, suggesting that cathedrals had a well-defined, but somewhat restricted appeal. Several cathedrals are attempting to widen their appeal by engaging a variety of events or exhibitions. Taking one specific example, the Brecon Jazz Festival, the present study found that 196 visitors to Brecon Cathedral during this period differed significantly from the standard psychological type profile of cathedral visitors in two ways. There were significantly more intuitive types (41% compared with 28%) and significantly more perceiving types (27% compared with 20%). These findings demonstrate that specific events have the capacity to widen the psychographic appeal of cathedrals

The (p,q) String Tension in a Warped Deformed Conifold

We find the tension spectrum of the bound states of p fundamental strings and q D-strings at the bottom of a warped deformed conifold. We show that it can be obtained from a D3-brane wrapping a 2-cycle that is stabilized by both electric and magnetic fluxes. Because the F-strings are Z_M-charged with non-zero binding energy, binding can take place even if (p,q) are not coprime. Implications for cosmic strings are briefly discussed.Comment: 17 pages, 1 figur

Topological Features in Ion Trap Holonomic Computation

Topological features in quantum computing provide controllability and noise error avoidance in the performance of logical gates. While such resilience is favored in the manipulation of quantum systems, it is very hard to identify topological features in nature. This paper proposes a scheme where holonomic quantum gates have intrinsic topological features. An ion trap is employed where the vibrational modes of the ions are coherently manipulated with lasers in an adiabatic cyclic way producing geometrical holonomic gates. A crucial ingredient of the manipulation procedures is squeezing of the vibrational modes, which effectively suppresses exponentially any undesired fluctuations of the laser amplitudes, thus making the gates resilient to control errors.Comment: 9 pages, 4 figures, REVTE