| 1. |
- Schoch, CL, et al.
(författare)
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Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 109:16, s. 6241-6246
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Tidskriftsartikel (refereegranskat)abstract
- Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.
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| 2. |
- Haines, M. G., et al.
(författare)
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Fiber Z-pinch Experiments and Calculations in the Finite Larmor Radius Regime
- 1996
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Ingår i: Laser and particle beams (Print). - 0263-0346 .- 1469-803X. ; 14, s. 261-271
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Tidskriftsartikel (refereegranskat)abstract
- The dense Z-pinch project at Imperial College is aimed at achieving radiative collapse to high density in a hydrogen plasma, and also to study plasmas close to controlled fusion conditions. To this end, the MAGPIE generator (2.4 MV, 1.25, and 200 ns) has been built and tested, and is now giving preliminary experimental data at 60% of full voltage for carbon and CD2 fibers. These discharges are characterized by an initial radial expansion followed by the occurrence of m = 0 structures with transient X-ray emission from bright spots. Late in the discharge a disruption can occur, accompanied by hard X-ray emission from the anode due to an energetic electron beam and, in the case of CD2 fibers, a neutron burst. Concomitant theoretical studies have solved the linear stability problem for a Z-pinch with large ion Larmor radii, showing that a reduction in growth rate of m = 0 and m = 1 modes to about 20% of the magnetohydrodynamic (MHD) value can occur for a parabolic density profile when the Larmor radius is optimally 20% of the pinch radius. Two dimensional MHD simulations of Z-pinches in two extremes of focussed short-pulse laserplasma interactions and of galactic jets reveal a nonlinear stabilizing effect in the presence of sheared flow. One-dimensional simulations show that at low line density the lower hybrid drift instability can lead to coronal radial expansion of a Z-pinch plasma.
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| 3. |
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| 4. |
- Arber, T. D., et al.
(författare)
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Large Larmor Radius Stability of the Z-pinch
- 1994
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 72, s. 2399-
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Tidskriftsartikel (refereegranskat)abstract
- The linear m=0 stability of the z pinch in the collisionless, large ion Larmor radius regime is examined using the Vlasov fluid model. The results reveal a strong equilibrium dependence. The uniform current density equilibrium shows a reduction in growth rate when the average ion Larmor radius is about one-fifth of the pinch radius. However, finite Larmor radius effects cannot in themselves produce a stabilized z pinch.
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| 5. |
- Arber, T. D., et al.
(författare)
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Linear Stability of the High Temperature, Dense Z-pinch
- 1995
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 74, s. 2698-
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented on the linear stability of the collisionless m=1 mode in a dense Z pinch. It is shown that a reduction in growth rate by a factor of about 10 (when compared to the zero Larmor radius result) is possible by initializing the Z pinch with a sufficiently low line density. With the completion of this work we conclude that linear, large Larmor radius effects cannot stabilize the high temperature, dense Z pinch. Such pinches will always exhibit linear m=0 or m=1 instabilities with growth times comparable to the radial Alfvén transit time.
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| 6. |
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| 7. |
- Cannon, P., et al.
(författare)
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Revisions of British and Irish Lichens vol. 3 - Peltigerales: Collemataceae (including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium.
- 2020
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Annan publikation (refereegranskat)abstract
- Revisions of British and Irish Lichens is a free-to-access serial publication under the auspices of the British Lichen Society, that charts changes in our understanding of the lichens and lichenicolous fungi of Great Britain and Ireland. Each volume will be devoted to a particular family (or group of families), and will include descriptions, keys, habitat and distribution data for all the species included. The maps are based on information from the BLS Lichen Database, that also includes data from the historical Mapping Scheme and the Lichen Ireland database. The choice of subject for each volume will depend on the extent of changes in classification for the families concerned, and the number of newly recognized species since previous treatments. To date, accounts of lichens from our region have been published in book form. However, the time taken to compile new printed editions of the entire lichen biota of Britain and Ireland is extensive, and many parts are out-of-date even as they are published. Issuing updates as a serial electronic publication means that important changes in understanding of our lichens can be made available with a shorter delay. The accounts may also be compiled at intervals into complete printed accounts, as new editions of the Lichens of Great Britain and Ireland.
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| 8. |
- Coppins, M., et al.
(författare)
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Anisotropic Z-Pinch Equilibria and Their Stability
- 1992
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Ingår i: Physics of fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; B4, s. 3251-
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Tidskriftsartikel (refereegranskat)abstract
- The Chew–Goldberger–Low equations are used to study the effect of pressure anisotropy on Z‐pinches operating in the collisionless regime. The limitations on the form of accessible equilibria are investigated. The effect on the m=0 instability is asessed both by means of the energy principle and by direct solution of the eigenvalue equation for a variety of anisotropicequilibria. The results indicate that in the small Larmor radius limit pressure anisotropy offers a rather slight enhancement of the linear stability of the Z‐pinch.
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| 9. |
- Coppins, M., et al.
(författare)
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CGL Anisotropic Equilibria and Stability
- 1989
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Ingår i: 2nd International Conference on High Density Pinches, Laguna Beach, CA, USA 1989. ; , s. 211-
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Konferensbidrag (refereegranskat)
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| 10. |
- Coppins, M., et al.
(författare)
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FIGARO-a Large Larmor Radius Stability Code
- 1992
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Ingår i: International Conference on Plasma Physics, Innsbruck, Austria, 29 June - 3 July, 1992. ; , s. 663-
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Konferensbidrag (refereegranskat)
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