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16 results on '"Webb, M.A."'

4. Digital mapping of a soil drainage index for irrigated enterprise suitability in Tasmania, Australia

Author

Kidd, D.B., Malone, B.P., McBratney, A.B., Minasny, B., and Webb, M.A.

Subjects
Soil research, Soil permeability -- Research, Digital mapping -- Methods, Drainage -- Research, Agricultural industry, Earth sciences
Abstract

An operational Digital Soil Assessment was developed to inform land suitability modelling in newly commissioned irrigation schemes in Tasmania, Australia. The Land Suitability model uses various soil parameters, along with other climate and terrain surfaces, to identify suitable areas for various agricultural enterprises for a combined 70000-ha pilot project area in the Meander and Midlands Regions of Tasmania. An integral consideration for irrigable suitability is soil drainage. Quantitative measurement and mapping can be resource-intensive in time and associated costs, whereas more 'traditional' mapping approaches can be generalised, lacking the detail required for statistically validated products. The project was not sufficiently resourced to undertake replicated field-drainage measurements and relied on expert field drainage estimates at ~930 sites (260 of these for independent validation) to spatially predict soil drainage for both areas using various terrain-based and remotely sensed covariates, using three approaches: (a) decision tree spatial modelling of discrete drainage classes; (b) regression-tree spatial modelling of a continuous drainage index; (c) regression kriging (random-forests with residual-kriging) spatial modelling of a continuous drainage index. Method b was chosen as the best approach in terms of interpretation, and model training and validation, with a concordance coefficient of 0.86 and 0.57, respectively. A classified soil drainage map produced from the 'index' showed good agreement, with a linearly weighted kappa coefficient of 0.72 for training, and 0.37 for validation. The index mapping was incorporated into the overall land suitability model and proved an important consideration for the suitability of most enterprises. Additional keywords: decision trees, digital soil mapping, land suitability, regression trees, random forests, soil drainage, spatial modelling. Received 25 March 2013, accepted 24 September 2013, published online 6 March 2014, Introduction Tasmania has a population of ~500000 people, with a cool temperate climate, and rainfall ranging from >500 mm [year.sup.-1] in the central Midlands to < 1800 mm [year.sup.-1] on [...]

Published
2014
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5. Does Completing an Enriched Writing Course Improve Writing Self-Efficacy of Talented Secondary Students?

Author

Anne Frank Webb M.A., Stevie Jeung, and Beverly J. Vandiver

Subjects
Self-efficacy, education, 05 social sciences, Writing process, 050301 education, 050109 social psychology, Education, Developmental and Educational Psychology, Mathematics education, 0501 psychology and cognitive sciences, Statistical analysis, sense organs, skin and connective tissue diseases, Association (psychology), Psychology, 0503 education
Abstract

This study examined whether writing self-efficacy would change and have an effect on final course grade in 267 talented middle and high school students in the course of taking enriched 6-week writing classes. Confidence in writing increased across time within three courses, whereas approach to writing did not. Differences were found between genders and between students taking different courses. In the writing process class, girls scored higher in their approach to writing at the end of class than boys. Girls obtained higher final grades than boys, but girls who had higher change in approach to writing obtained higher final grades than (a) boys who reported a higher change and (b) both boys and girls who reported less change. A unique association may exist between talented students’ gender and change in self-efficacy on final course grade.

Published
2015

6. Mortality and occupational exposure to radiation: first analysis of the National Registry for Radiation Workers

Author

Kendall, G.M., Muirhead, C.R., MacGibbon, B.H., O'Hagan, J.A., Conquest, A.J., Goodill, A.A., Butland, B.K., Fell, T.P., Jackson, D.A., Webb, M.A., Haylock, R.G.E., Thomas, J.M., and Silk, T.J.

Subjects
Radiation workers -- Diseases, Cancer -- Environmental aspects, Leukemia -- Environmental aspects, Multiple myeloma -- Environmental aspects, Radiation -- Health aspects
Published
1992

8. Polarization effects in thallium bromide x-ray detectors

Author

Kozorezov, A., Gostilo, V., Owens, A., Quarati, F., Shorohov, M., Webb, M.A., and Wigmore, J.K.

Subjects
Holes (Electron deficiencies) -- Analysis, Synchrotron radiation -- Usage, Thallium compounds -- Electric properties, Thallium compounds -- Optical properties, Physics
Abstract

Several experimental measurements are conducted to explain the different polarization effects that are exhibited by the thallium bromide planar x-ray detectors. The spectroscopic characteristics, peak height and energy resolution of the system are shown to significantly reduce after the radiation threshold limit.

Published
2010

10. Follicles, germinal centers, and immune mechanisms in primary biliary cirrhosis

Author

M.R.C.P. Gwilym J. Webb M.A. and F.R.C.P. Gideon M. Hirschfield Ph.D.

Subjects
Male, Hepatology, business.industry, Liver Cirrhosis, Biliary, Germinal center, T-Lymphocytes, Helper-Inducer, medicine.disease, Article, Primary biliary cirrhosis, Immunology, Medicine, Humans, Female, business, Immune mechanisms
Abstract

There is increasing interest in the role of T follicular helper (Tfh) cells in autoimmunity from the perspective of both their role in breach of tolerance and their effects on the natural history of disease progression. Indeed, the critical role of Tfh cells in autoimmunity is further highlighted based on their location in the germinal center (GC), a pathogenic hot spot for development of autoreactivity. To address the role of Tfh cells in primary biliary cirrhosis (PBC), we comprehensively evaluated the immunobiology of CXCR5+CD4+ Tfh cells in 69 patients with PBC, including a nested subgroup of 16 autoimmune hepatitis (AIH) and 20 healthy controls (HC), followed for one year. We report herein several key observations. Firstly, there was an increased frequency of circulating Tfh cells in patients with PBC compared to AIH (p < 0.05) and HC (p < 0.01). Second, the function of circulating Tfh cells from PBC patients, including IL-21 production (p < 0.05), the ability to promote B cell maturation and autoantibody production, were greater than HC. Third, the frequency of these cells was significantly decreased in UDCA responders compared to UDCA-treated non-responders, in both cross-sectional (p = 0.023) and longitudinal studies (p = 0.036),respectively. Indeed, similar increases of Tfh cells were noted in liver and spleen. In conclusion, these results significantly extend our understanding of lymphoid subpopulations in PBC and their relative role in disease expression. Our data also provide a novel biomarker for evaluation of the effectiveness of new therapeutic approaches.

Published
2014

12. Shake the disease

Author

Murray, Rob and Webb, M.A.

Subjects
General interest, News, opinion and commentary
Abstract

Another fine article by Anne Kingston on multiple sclerosis (' 'Canada's disease,' ' Society, April 27). At the turn of the century, MS was called faker's disease. Eventually, radiology showed [...]

Published
2015

13. Synchrotron x-ray fluorescence (SXRF) analysis of palaeofluid chemistry from the McArthur River uranium deposit, Athabasca Basin, Canada: results and implications.

Author

McCready A.J., Uranium production and raw materials for the nuclear fuel cycle: supply and demand, economics, the environment and energy security: Extended synopses, Vienna 20-Jun-0524-Jun-05 IAEA; OECD Nuclear Energy Agency; The World Nuclear Association; The Nuclear Energy Institute; UNECE, Annesley I.R., Bakker R.J., Cavell R.G., Cuney M., Derome D., Rickers K., Webb M.A., McCready A.J., Uranium production and raw materials for the nuclear fuel cycle: supply and demand, economics, the environment and energy security: Extended synopses, Vienna 20-Jun-0524-Jun-05 IAEA; OECD Nuclear Energy Agency; The World Nuclear Association; The Nuclear Energy Institute; UNECE, Annesley I.R., Bakker R.J., Cavell R.G., Cuney M., Derome D., Rickers K., and Webb M.A.

Abstract

The 20 to 50 micron fluid inclusions investigated were either from inclusion-rich quartz or occurred as isolated inclusions in quartz. Solid phases included halite, phyllosilicates and haematite. All the inclusions contained Fe, Br and Sr along with a number of other elements, including U. Elements that are known to be present from microthermometry were either not detected (including Na and Cl) or only detected occasionally (K, Ca); SXRF is probably more suited to analysing elements with a heavier mass than these. The presence of U in the inclusions indicates that fluids trapped within the quartz were able to transport significant amounts of metals, including U and LREE. The presence of Ce could indicate that uranium was sourced from monazite. Uranium also occurred in inclusion-free quartzes, which could suggest that the ore-fluid was saturated with respect to uranium., The 20 to 50 micron fluid inclusions investigated were either from inclusion-rich quartz or occurred as isolated inclusions in quartz. Solid phases included halite, phyllosilicates and haematite. All the inclusions contained Fe, Br and Sr along with a number of other elements, including U. Elements that are known to be present from microthermometry were either not detected (including Na and Cl) or only detected occasionally (K, Ca); SXRF is probably more suited to analysing elements with a heavier mass than these. The presence of U in the inclusions indicates that fluids trapped within the quartz were able to transport significant amounts of metals, including U and LREE. The presence of Ce could indicate that uranium was sourced from monazite. Uranium also occurred in inclusion-free quartzes, which could suggest that the ore-fluid was saturated with respect to uranium.

Published
2006

15. X-Ray response of CZT ring-drift detector

Author

Kozorezov, A.G., primary, Owens, A., additional, den Hartog, R., additional, Wigmore, J.K., additional, Gostilo, V., additional, Kondratjev, V., additional, Loupilov, A., additional, Webb, M.A., additional, and Welter, E., additional

Published
2007
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