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Outstanding Junior Investigator Award. Final report
No full textThe OJI supported research of J. Ellison has been concentrated in two areas: study of W{gamma} and Z{gamma} production at the Tevatron, which probes the trilinear boson coupling; design, fabrication and testing of silicon microstrip detectors for the D0 upgrade silicon tracking system. The W{gamma} analysis using data from the first D0 run ({approximately}14 pb{sup {minus}1} integrated luminosity) has been completed - J. Ellison and a postdoctoral research working with him (B. Choudhary) were responsible for the muon channel analysis. This analysis is an important test of the Standard Model (SM), since it probes the nature of the WW{gamma} coupling, which is related to the W boson magnetic dipole and electric quadrupole moments. Any deviation from the SM value of the WW{gamma} coupling would be an indication of either composite structure of the W or higher order loop corrections involving physics beyond the SM. The analysis has resulted in the world`s most sensitive limits on the WW{gamma} coupling parameters. In addition the author has also worked on an analysis of Z{gamma} production which has yielded sensitive limits on the ZZ{gamma} and Z{gamma}{gamma} couplings. The work on the D0 Silicon Tracker has also made very good progress. The team led by J. Ellison includes two postdoctoral researchers (A. Bischoff and C. Boswell), one graduate student (M. Mason) and three undergraduate students. They have fully evaluated proptotype detectors which were designed at UCR and have completed a detailed simulation study of the detector performance for different strip geometries. The results were used to optimize the design of the final D0 detectors, for which UR has sole responsibility. The author has completed the mask design for the 3-chip barrel detectors and production of the final detectors as now begun
Sediment Carbon Accumulation in Southern Latitude Saltmarsh Communities of Tasmania, Australia
No full textCarbon sequestration values of wetlands are greatest in their sediments. Northern hemisphere research dominates the earlier saltmarsh carbon sequestration literature, recently augmented by analyses across mainland Australia where species assemblages, catchment histories and environmental settings differ. No previous assessment has been made for Tasmania. Carbon stores and accumulation rates in saltmarsh sediments of the Rubicon estuary, Tasmania, were investigated. Carbon was determined from sediment cores by Elemental Analyser, combined with analysis of organic content and bulk density. Carbon accumulation was determined using short-term and long-term sediment accretion indicators. Results showed carbon densities to be lower than global averages, with variation found between carbon stores of native and introduced species zones. Cores from introduced Spartina anglica indicated a trend of higher sediment carbon percentages relative to cores from native saltmarsh Juncus kraussii and Sarcocornia quinqueflora, and in finer grain sizes. Sediment carbon stock of 30 cm depths was 49.5 Mg C ha−1 for native saltmarsh and 55.5 Mg C ha−1 for Spartina. Carbon percentages were low owing to high catchment inorganic sediment yields, however carbon accumulation rates were similar to global averages, particularly under Spartina. Covering 85% of saltmarsh area in the estuary, Spartina contributes the majority to carbon stores, potentially indicating a previously unrecognized value for this invasive species in Australia
Clonal expansion of early to mid-life mitochondrial DNA point mutations drives mitochondrial dysfunction during human ageing
No full textAge-related decline in the integrity of mitochondria is an important contributor to the human ageing process. In a number
of ageing stem cell populations, this decline in mitochondrial function is due to clonal expansion of individual mitochondrial
DNA (mtDNA) point mutations within single cells. However the dynamics of this process and when these mtDNA mutations
occur initially are poorly understood. Using human colorectal epithelium as an exemplar tissue with a well-defined stem cell
population, we analysed samples from 207 healthy participants aged 17–78 years using a combination of techniques
(Random Mutation Capture, Next Generation Sequencing and mitochondrial enzyme histochemistry), and show that: 1)
non-pathogenic mtDNA mutations are present from early embryogenesis or may be transmitted through the germline,
whereas pathogenic mtDNA mutations are detected in the somatic cells, providing evidence for purifying selection in
humans, 2) pathogenic mtDNA mutations are present from early adulthood (,20 years of age), at both low levels and as
clonal expansions, 3) low level mtDNA mutation frequency does not change significantly with age, suggesting that mtDNA
mutation rate does not increase significantly with age, and 4) clonally expanded mtDNA mutations increase dramatically
with age. These data confirm that clonal expansion of mtDNA mutations, some of which are generated very early in life, is
the major driving force behind the mitochondrial dysfunction associated with ageing of the human colorectal epitheliumFood Standards Agency (N12015), NIHR Newcastle Biomedical Research Centre based at Newcastle upon Tyne
Hospitals National Health Service Foundation Trust and Newcastle University, the Wellcome Trust Centre for Mitochondrial Research (096919Z/11/Z), the Medical
Research Council (UK) Centre for Translational Muscle Disease research (G0601943) and the UK NHS Highly Specialised ‘‘Rare Mitochondrial Disorders of Adults
and Children’’ Service, the Newcastle University Centre for Brain Ageing and Vitality supported by the BBSRC, EPSRC, ESRC, and MRC as part of the cross-council
Lifelong Health and Wellbeing Initiative (G0700718), the Ellison Medical Foundation and the NIA(R01AG19787
Concentration in Knowledge Output: A case of Economics Journals
No full textThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
Holocene sea level record of Tongatapu, Kingdom of Tonga, from pollen analysis of mangrove sediments
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