17,851 research outputs found
Study of applications of a tracking filter to stabilize large flexible launch vehicles Final technical report
Adaptive tracking filter for stabilization of launch vehicle
Restoration of eucalypt grassy woodland: effects of experimental interventions on ground-layer vegetation
We report on the effects of broad-scale restoration treatments on the ground layer of eucalypt grassy woodland in south-eastern Australia. The experiment was conducted in two conservation reserves from which livestock grazing had previously been removed. Changes in biomass, species diversity, ground-cover attributes and life-form were analysed over a 4-year period in relation to the following experimental interventions: (1) reduced kangaroo density, (2) addition of coarse woody debris and (3) fire (a single burn). Reducing kangaroo density doubled total biomass in one reserve, but no effects on exotic biomass, species counts or ground cover attributes were observed. Coarse woody debris also promoted biomass, particularly exotic annual forbs, as well as plant diversity in one of the reserves. The single burn reduced biomass, but changed little else. Overall, we found the main driver of change to be the favourable growth seasons that had followed a period of drought. This resulted in biomass increasing by 67%, (mostly owing to the growth of perennial native grasses), whereas overall native species counts increased by 18%, and exotic species declined by 20% over the 4-year observation period. Strategic management of grazing pressure, use of fire where biomass has accumulated and placement of coarse woody debris in areas of persistent erosion will contribute to improvements in soil and vegetation condition, and gains in biodiversity, in the future.Funding and in-kind logistic support for this project was
provided by the ACT Government as part of an Australian Research
Council Linkage Grant (LP0561817; LP110100126). Drafts of the
manuscript were read by Saul Cunningham and Ben Macdonald
A descriptive literature review of Recognition of Prior Learning for vocational learners in emergency medical care in South Africa
Radical advances in emergency medical care education in South Africa have resulted in both advancements and suppression. After short-course vocational training, the emergency care provider could seek employment in an emergency service. With the realignment of emergency medical care programmes to the National Qualifications Framework (NQF), these short vocational courses were phased out by 2018. Although necessary for educational advancement, these changes prevented vocationally trained emergency care providers from articulating into higher education without returning to full-time academia. Moreover, despite recognition of prior learning (RPL) policies in higher education, few institutes offering emergency medical care programmes offered this as an access option.
This descriptive literature review aimed to analyse the RPL processes in South Africa and globally. Additionally, insight into RPL candidates” support requirements for postgraduate studies was gained. A systematic search of peer-reviewed journal articles, periodicals, dissertations, and governmental reports from 2000 to 2021 was conducted. Various databases were accessed, including Proquest, EBSCOhost, LearnTechLib, JSTOR, ERIC, Google Scholar, and the Thesis Repository. The lack of literature focusing on the prehospital RPL system in South Africa prompted search expansions into the field of health science internationally. Of the 401 screened sources, 19 met the researcher’s inclusion criteria. Two additional articles were sourced in a repeated search in February 2022. The findings revealed enablers and barriers for RPL students and expanded on their personal and academic transitions. The themes identified through the enablers and barriers can assist in identifying additional support for RPL students during their educational journey. Ultimately, despite vital institutional transitions in RPL processes, intrinsic motivation inspired these students to embrace the challenges they faced, and their process of personal transition and lifelong learning began
Computer vision
The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed
Performance of alumina-supported Pt catalysts in an electron-beam-sustained CO2 laser amplifier
The performance of an alumina-supported Pt catalyst system used to maintain the gas purity in an electron-beam-sustained (636) isotope CO2 laser amplifier has been tested. The system characteristics using the two-zone, parallel flow reactor were determined for both continuous- and end-of-day reactor operation using on-line mass spectrometric sampling. The laser amplifier was run with an energy loading of typically 110 J-l/atm and an electron-beam current of 4 mA/sq cm. With these conditions and a pulse repetition frequency of 10 Hz for up to 10,000 shots, increases on the order of 100 ppm O2 were observed with the purifier on and 150 ppm with it off. The 1/e time recovery time was found to be approximately 75 minutes
Parametric vision simulation study, part 2 Final report
Effects of landing site redesignation on visibility during manned lunar landin
The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures
Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities
Associations Between Social Media and Well-Being and Sleep Quality in Medical and Health Professions
This study was conducted to assess associations between social media use and overall well-being and sleep quality in medical and health professions graduate students. A cross-sectional survey was distributed to examine demographic information, social media use, and health behaviors and outcomes. Logistic regression analysis was conducted to examine the relationships between sleep quality and potential covariates and/or independent variables, while proportional odds regression was performed to analyze potential associations between emotional wellbeing and independent variables. Survey respondents were more likely to have a low or depressed mood if they used social media as a way to help them sleep [odds ratio=2.1, 95% confidence interval = (1.0, 4.2)]. Participants who used social media to help them sleep also had poorer sleep quality than those who did not use social media for that purpose [odds ratio=2.3, 95% confidence interval= (1.1, 4.7)]. In addition, individuals who used social media to obtain health-related advice or information were 2.8 times [95% confidence interval= (1.4, 5.8)] more likely to have poor sleep quality compared to those who did not use social media for health-related advice or information. These study results expound upon the relationship between social media use and health outcomes in medical and graduate students
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