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result(s) for
"Keast, David"
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Magnitude Frequency Analysis of Small Floods Using the Annual and Partial Series
2013
Flood frequency analysis using partial series data has been shown to provide better estimates of small to medium magnitude flood events than the annual series, but the annual series is more often employed due to its simplicity. Where partial series average recurrence intervals are required, annual series values are often “converted” to partial series values using the Langbein equation, regardless of whether the statistical assumptions behind the equation are fulfilled. This study uses data from Northern Tasmanian stream-gauging stations to make empirical comparisons between annual series and partial flood frequency estimates and values provided by the Langbein equation. At T = 1.1 years annual series estimates were found to be one third the magnitude of partial series estimates, while Langbein adjusted estimates were three quarters the magnitude of partial series estimates. The three methods converged as average recurrence interval increased until there was no significant difference between the different methods at T = 5 years. These results suggest that while the Langbein equation reduces the differences between the quantile estimates of annual maxima derived from annual maxima series and partial duration series flood frequency estimates, it does not provide a suitable alternative method to using partial series data. These results have significance for the practical estimation of the magnitude-frequency of small floods.
Journal Article
Effect of Electrical Stimulation on Chronic Leg Ulcer Size and Appearance
2003
Background and Purpose. Electrical current has been recommended for use on chronic pressure ulcers; however, the ability of this modality to improve healing of other types of chronic ulcers is less well established. The purpose of this study was to examine the effect of high-voltage pulsed current (HVPC) on healing of chronic leg ulcers. Subjects. Twenty-seven people with 42 chronic leg ulcers participated in the study. Methods. The subjects were separated into subgroups according to primary etiology of the wound (diabetes, arterial insufficiency, venous insufficiency) and then randomly assigned to receive either HVPC (100 microseconds, 150 V, 100 Hz) or a sham treatment for 45 minutes, 3 times weekly, for 4 weeks. Wound surface area and wound appearance assessed during an initial examination, following a 1- to 2-week period during which subjects received only conventional wound therapy, after 4 weeks of sham or HVPC treatment, and at 1 month following treatments. Results The results indicated that HVPC applied to chronic leg ulcers reduced the wound surface area over the 4-week treatment period to approximately one half the initial wound size (mean decrease=44.3%, SD=8.8%, range=2.8%-100%), which was over 2 times greater than that observed in wounds treated with sham units (mean decrease=16.0%, SD=8.9%, range=-30.3%-83.7%). Discussion and Conclusion. The results of the study indicate that HVPC administered 3 times a week should be considered to accelerate wound closure of chronic leg ulcers.
Journal Article
Siderophore production by actinomycetes isolates from two soil sites in Western Australia
by
Keast, David
,
Carson, Kerry C.
,
Soon, Hooi Peng
in
Actinobacteria - genetics
,
Actinobacteria - metabolism
,
Bacteria
2012
The actinomycetes are metabolically flexible soil micro-organisms capable of producing a range of compounds of interest, including siderophores. Siderophore production by actinomycetes sampled from two distinct and separate geographical sites in Western Australia were investigated and found to be generally similar in the total percentage of siderophore producers found. The only notable difference was the proportion of isolates producing catechol siderophores with only 3% found in site 1 (from the north-west of Western Australia and reportedly containing 40% magnetite) and 17% in site 2 (a commercial stone fruit orchard in the hills east of Perth with a soil base ranging from sandy loam to laterite). Further detailed characterization of isolates of interest identified a
Streptomyces
that produced extracellularly excreted enterobactin, the characteristic Enterobacteriaceae siderophore, and also revealed some of the conditions required for enterobactin production. Carriage of the
entF
gene, which codes for the synthetase responsible for the final assembly of the tri-cyclic structure of enterobactin, was confirmed by PCR in this isolate. Another separate
Streptomyces
produced a compound that matched the UV/VIS spectra of heterobactin, a siderophore previously only described in
Rhodococcus
and
Nocardia
.
Journal Article
Part-time university education
1998
Keast outlines the results of survey research on part-time programming at Canadian universities and the needs and characteristics of undergraduate student populations with potential for part-time degree completion. Data on Canadian universities were examined in four major categories of variables including institutional backgrounds, part-time degree programs and program administration, evening and weekend course offerings and course administration, and services for part-time students. Data from student groups were examined in six categories including demographics, academic backgrounds, finances and employment, educational expectations and student services, technology and alternative delivery methods, and advantages and disadvantages of part-time attendance. Findings suggest changes may be necessary in university functioning in order to serve part-time student populations better. Implications for institutional policy and practice are discussed in four general areas: part-time enrolments and degrees; evening and weekend programming; demographics, student services and cost-effectiveness; and technology and alternative delivery.
Journal Article
Studying Part-Time at University: From Research to Policy to Practice
2000
In the last few years universities in Canada have seen a noticeable decline in part-time enrollments. This trend has given rise to a number of pressing concerns regarding the needs and aspirations of part-time students and the status and future of part-time study. Unfortunately, these concerns exist against a backdrop of relatively little research on part- time university students, programs, and attendance which is useful for decisions on policy and practice. This paper highlights the results of research which examined part-time programming at Canadian universities and the needs and characteristics of undergraduate student populations with potential for part-time degree completion. It is argued that the mature, working, part-time learner constitutes a distinct nontraditional group, with a distinct set of educational needs and expectations. The findings suggest changes which may be necessary in university functioning in order to better serve these student populations in the future. Results are compared with other recent research and implications for institutional policy and practice are discussed.
Journal Article
Psychological and immunological correlates of acute overtraining
by
Grove, J R
,
Morton, A R
,
Zeroni, P M
in
Adaptation, Physiological
,
Adult
,
Affect - physiology
1994
Five men undertook two intensive interval training sessions per day for 10 days, followed by 5 days of active recovery. Subjects supplied a venous blood sample and completed a mood-state questionnaire on days 1, 6, 11 and 16 of the study. Performance capabilities were assessed on days 1, 11 and 16 using a timed treadmill test to exhaustion at 18 kmh-1 and 1% grade. These individuals became acutely overtrained as indicated by significant reductions in running performance from day 1 to day 11. The overtrained state was accompanied by severe fatigue, immune system deficits, mood disturbance, physical complaints, sleep difficulties, and reduced appetite. Mood states moved toward baseline during recovery, but feelings of fatigue and immune system deficits persisted throughout the study.
Journal Article
Development, validity, reliability, and responsiveness of a new leg ulcer measurement tool
2004
To develop and validate an assessment tool--the Leg Ulcer Measurement Tool (LUMT)--that would be able to detect changes in the appearance of lower extremity ulcers.
Twenty-two subjects with chronic leg ulcers of various etiologies (arterial, venous, diabetes) participated in the validation study.
An interdisciplinary panel consisting of 9 local wound care specialists confirmed content validity. Concurrent criterion validity was determined by correlation of the size domain (1 of 14 clinician-rated domains in the LUMT) with acetate tracing measurement of wound surface area. Reliability was determined using repeated assessments by 4 wound care specialist and 2 inexperienced evaluators; responsiveness was determined using monthly reassessments by a single rater for 4 months.
Concurrent criterion validity was r = 0.82. Excellent values of intrarater and interrater reliability (ICC > 0.75) were obtained for total LUMT scores and for many of the 14 individual domains; however, several domains were found to be less reproducible. The LUMT detected change in wound status over time (responsiveness coefficient = 0.84).
The LUMT can be used by 1 or more assessors, with relatively little previous training, to make reproducible evaluations of lower extremity ulcer appearance and to document change in appearance over time. The LUMT represents a novel assessment tool specifically designed and validated for clinical or research use on chronic leg ulcers.
Journal Article