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Search Results: 1 - 10 of 232537 matches for " Simon R Ellwood "
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Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula
Lars G Kamphuis, Judith Lichtenzveig, Richard P Oliver, Simon R Ellwood
BMC Plant Biology , 2008, DOI: 10.1186/1471-2229-8-30
Abstract: Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (<48 h) between the resistant and susceptible genotypes, except pathogen growth was restricted to one or a few host cells in SA27063. In both interactions reactive oxygen intermediates and phenolic compounds were produced, and cell death occurred. Two F2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 × A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P < 0.00001) named resistance to the necrotroph Phoma medicaginis one (rnpm1) genetically mapped to the top arm of linkage group 4 (LG4). rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1–5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P < 0.00001), rnpm2, was located on the lower arm of LG8 in the SA27063 × SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR) genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs) are apparent in the genomic sequence of the reference accession A17 at the rnpm2 locus.The induction of defence responses and cell death in the susceptible interaction following infection by P. med
A first genome assembly of the barley fungal pathogen Pyrenophora teres f. teres
Simon R Ellwood, Zhaohui Liu, Rob A Syme, Zhibing Lai, James K Hane, Felicity Keiper, Caroline S Moffat, Richard P Oliver, Timothy L Friesen
Genome Biology , 2010, DOI: 10.1186/gb-2010-11-11-r109
Abstract: The total assembly was 41.95 Mbp and contains 11,799 gene models of 50 amino acids or more. Comparison against two sequenced BACs showed that complex regions with a high GC content assembled effectively. Electrophoretic karyotyping showed distinct chromosomal polymorphisms between isolates 0-1 and 15A, and cytological karyotyping confirmed the presence of at least nine chromosomes. The genetic map spans 2477.7 cM and is composed of 243 markers in 25 linkage groups, and incorporates simple sequence repeat markers developed from the assembly. Among predicted genes, non-ribosomal peptide synthetases and efflux pumps in particular appear to have undergone a P. teres f. teres-specific expansion of non-orthologous gene families.This study demonstrates that paired-end Solexa sequencing can successfully capture coding regions of a filamentous fungal genome. The assembly contains a plethora of predicted genes that have been implicated in a necrotrophic lifestyle and pathogenicity and presents a significant resource for examining the bases for P. teres f. teres pathogenicity.Net blotch of barley (Hordeum vulgare) is caused by Pyrenophora teres Drechsler (anamorph Drechslera teres [Sacc.] Shoem.). P. teres is an ascomycete within the class Dothideomycetes and order Pleosporales. This order contains plant pathogens responsible for many necrotrophic diseases in crops, including members of the genera Ascochyta, Cochliobolus, Pyrenophora, Leptosphaeria and Stagonospora. Net blotch is a major disease worldwide that causes barley yield losses of 10 to 40%, although complete loss can occur with susceptible cultivars in the absence of fungicide treatment [1]. In Australia the value of disease control is estimated at $246 million annually with average direct costs of $62 million annually, making it the country's most significant barley disease [2].Net blotch exists in two morphologically indistinguishable but genetically differentiated forms: P. teres f. teres (net form of net blotch,
Construction of a comparative genetic map in faba bean (Vicia faba L.); conservation of genome structure with Lens culinaris
Simon R Ellwood, Huyen TT Phan, Megan Jordan, James Hane, Anna M Torres, Carmen M Avila, Serafín Cruz-Izquierdo, Richard P Oliver
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-380
Abstract: Of 796 intron-targeted amplified polymorphic (ITAP) markers screened, 151 markers could be used to construct a comparative genetic map. Linkage analysis revealed seven major and five small linkage groups (LGs), one pair and 12 unlinked markers. Each LG was comprised of three to 30 markers and varied in length from 23.6 cM to 324.8 cM. The map spanned a total length of 1685.8 cM. A simple and direct macrosyntenic relationship between faba bean and Medicago truncatula was evident, while faba bean and lentil shared a common rearrangement relative to M. truncatula. One hundred and four of the 127 mapped markers in the 12 LGs, which were previously assigned to M. truncatula genetic and physical maps, were found in regions syntenic between the faba bean and M. truncatula genomes. However chromosomal rearrangements were observed that could explain the difference in chromosome numbers between these three legume species. These rearrangements suggested high conservation of M. truncatula chromosomes 1, 5 and 8; moderate conservation of chromosomes 2, 3, 4 and 7 and no conservation with M. truncatula chromosome 6. Multiple PCR amplicons and comparative mapping were suggestive of small-scale duplication events in faba bean. This study also provides a preliminary indication for finer scale macrosynteny between M. truncatula, lentil and faba bean. Markers originally designed from genes on the same M. truncatula BACs were found to be grouped together in corresponding syntenic areas in lentil and faba bean.Despite the large size of the faba bean genome, comparative mapping did not reveal evidence for polyploidisation, segmental duplication, or significant rearrangements compared to M. truncatula, although a bias in the use of single locus markers may have limited the detection of duplications. Non-coding repetitive DNA or transposable element content provides a possible explanation for the difference in genome sizes. Similar patterns of rearrangements in faba bean and lentil compare
The American challenge in uniform: the arrival of America’s armies in World War II and European women
David Ellwood
European Journal of American Studies , 2012, DOI: 10.4000/ejas.9577
Abstract: A vast body of material exists – memoirs, diaries, films, plays, novels, official records – on the impact and reception of America’s armed forces armies in Europe after 1942. Britain, Italy, France, Austria and of course Germany all offer relevant evidence. The popular British phrase about the GI’s being ‘over-paid, over-sexed and over here’ brilliantly sums up many of the tensions the encounter threw up: over money and life-styles, courtship rituals and the treatment of local women, over sovereignty and the American impulse to requisition every local resource they could get their hands on. Local men thought ‘their’ women were being requisitioned. The Americans had not come to do ‘nation-building’, and yet their presence left memories, changed attitudes and altered prospects on the future, especially among women. Afterwards American experts claimed that their armed forces had set off a ‘revolution of rising expectations’. Although a contradictory, complex encounter, there is enough evidence to suggest they might have been right.
Record-Breaking Early Flowering in the Eastern United States
Elizabeth R. Ellwood, Stanley A. Temple, Richard B. Primack, Nina L. Bradley, Charles C. Davis
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053788
Abstract: Flowering times are well-documented indicators of the ecological effects of climate change and are linked to numerous ecosystem processes and trophic interactions. Dozens of studies have shown that flowering times for many spring-flowering plants have become earlier as a result of recent climate change, but it is uncertain if flowering times will continue to advance as temperatures rise. Here, we used long-term flowering records initiated by Henry David Thoreau in 1852 and Aldo Leopold in 1935 to investigate this question. Our analyses demonstrate that record-breaking spring temperatures in 2010 and 2012 in Massachusetts, USA, and 2012 in Wisconsin, USA, resulted in the earliest flowering times in recorded history for dozens of spring-flowering plants of the eastern United States. These dramatic advances in spring flowering were successfully predicted by historical relationships between flowering and spring temperature spanning up to 161 years of ecological change. These results demonstrate that numerous temperate plant species have yet to show obvious signs of physiological constraints on phenological advancement in the face of climate change.
Open string field theory without open strings
Ian Ellwood,Washington Taylor
Physics , 2001, DOI: 10.1016/S0370-2693(01)00673-6
Abstract: Witten's cubic open string field theory is expanded around the perturbatively stable vacuum, including all scalar fields at levels 0, 2, 4 and 6. The (approximate) BRST cohomology of the theory is computed, giving strong evidence for the absence of physical open string states in this vacuum.
Gauge Invariance and Tachyon Condensation in Open String Field Theory
Ian Ellwood,Washington Taylor
Physics , 2001,
Abstract: The gauge invariance of open string field theory is considered from the point of view of level truncation, and applications to the tachyon condensation problem are discussed. We show that the region of validity of Feynman-Siegel gauge can be accurately determined using the level truncation method. We then show that singularities previously found in the tachyon effective potential are gauge artifacts arising from the boundary of the region of validity of Feynman-Siegel gauge. The problem of finding the stable vacuum and tachyon potential without fixing Feynman-Siegel gauge is addressed.
Peres-Horodecki separability criterion for continuous variable systems
R. Simon
Physics , 1999, DOI: 10.1103/PhysRevLett.84.2726
Abstract: The Peres-Horodecki criterion of positivity under partial transpose is studied in the context of separability of bipartite continuous variable states. The partial transpose operation admits, in the continuous case, a geometric interpretation as mirror reflection in phase space. This recognition leads to uncertainty principles, stronger than the traditional ones, to be obeyed by all separable states. For all bipartite Gaussian states, the Peres-Horodecki criterion turns out to be necessary and sufficient condition for separability.
The use of evidence in public governmental reports on health policy: an analysis of 17 Norwegian official reports (NOU)
Simon Innv?r
BMC Health Services Research , 2009, DOI: 10.1186/1472-6963-9-177
Abstract: This study uses the 'Index of Scientific Quality' (ISQ) to analyse all Norwegian official reports (NOUs) that were: (1) published by the Norwegian Ministry of Health and Care Services during 1994-1998 (N = 20); and (2) concerned with questions of effect either because these were included in the mandate or as a result of the committee's interpretation of the mandate. The ISQ is based on scientific criteria common in all research concerning questions of effect. The primary outcome measure is an ISQ score on a five-point scale.Three reports were excluded because their mandates, or the committees' interpretations of them, did not address questions of effect. For the remaining 17 NOUs in our study, overall ISQ scores were low for systematic literature search and for explicit validation of research. Two reports had an average score of three or higher, while scores for five other reports were not far behind. How committees assessed the relevant factors was often unclear.The reports' evaluations of health evidence in relation to questions of effect lacked transparency and, overall, showed little use of systematic processes. A systematic, explicit and transparent approach, following the standards laid down in the ISQ, may help generate the evidence-based decision-making that Norway, the UK, the EU and the WHO desire and seek. However, policy-makers may find the ISQ criteria for assessing the scientific quality of a report too narrow to adequately inform policy-making.Nearly 30 years ago, Lindblom and Cohen stated: '... in public policy making, many suppliers and users of social research are dissatisfied, the former because they are not listened to, the latter because they do not hear much they want to listen to' [1]. Twenty years later, the British government asked for policy that was 'shaped by the evidence rather than a response to short-term pressures' [2]. This quest for evidence by the British government exemplified a new trend in modern policy-making and, since the ear
Moments of the Wigner Distribution and a Generalized Uncertainty Principle
R. Simon,N. Mukunda
Physics , 1997,
Abstract: The nonnegativity of the density operator of a state is faithfully coded in its Wigner distribution, and this places constraints on the moments of the Wigner distribution. These constraints are presented in a canonically invariant form which is both concise and explicit. Since the conventional uncertainty principle is such a constraint on the first and second moments, our result constitutes a generalization of the same to all orders. Possible application in quantum state reconstruction using optical homodyne tomography is noted.
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