999 resultados para Distance geometry


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An important part of educating students in electronics and electrical engineering is laboratory practicals. Providing effective practical experience to students by distance education has always been a significant challenge to the engineering educator. Deakin University has for many years taught practicals in basic digital electronics to off-campus students by means of a kit. The same students have performed related exercises in analogue electronics, which require generating and measuring AC signals, by means of either software simulations or on-campus attendance at lab classes. This year, for the first time, off-campus students are being provided with a new kit, which contains a low-cost, battery-powered AC signal generator, and an interface that allows a PC to be used as an oscilloscope. This kit allows the off-campus student further flexibility in learning basic electronics.

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The benefit of impact-loading activity for bone strength depends on whether the additional bone mineral content (BMC) accrued at loaded sites is due to an increased bone size, volumetric bone mineral density (vBMD) or both. Using magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA), the aim of this study was to characterize the geometric changes of the dominant radius in response to long-term tennis playing and to assess the influence of muscle forces on bone tissue by investigating the muscle–bone relationship. Twenty tennis players (10 men and 10 women, mean age: 23.1 ± 4.7 years, with 14.3 ± 3.4 years of playing) were recruited. The total bone volume, cortical volume, sub-cortical volume and muscle volume were measured at both distal radii by MRI. BMC was assessed by DXA and was divided by the total bone volume to derive vBMD. Grip strength was evaluated with a dynamometer. Significant side-to-side differences (P < 0.0001) were found in muscle volume (+9.7%), grip strength (+13.3%), BMC (+13.5%), total bone volume (+10.3%) and sub-cortical volume (+20.6%), but not in cortical volume (+2.6%, ns). The asymmetry in total bone volume explained 75% of the variance in BMC asymmetry (P < 0.0001). vBMD was slightly higher on the dominant side (+3.3%, P < 0.05). Grip strength and muscle volume correlated with all bone variables (except vBMD) on both sides (r = 0.48–0.86, P < 0.05–0.0001) but the asymmetries in muscle parameters did not correlate with those in bone parameters. After adjustment for muscle volume or grip strength, BMC was still greater on the dominant side. This study showed that the greater BMC induced by long-term tennis playing at the dominant radius was associated to a marked increase in bone size and a slight improvement in volumetric BMD, thereby improving bone strength. In addition to the muscle contractions, other mechanical stimuli seemed to exert a direct effect on bone tissue, contributing to the specific bone response to tennis playing.

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The Little Penguin (Eudyptula minor), a colonial-nesting seabird that is widespread in New Zealand and southern Australia, has high dispersal potential but exhibits regional variation in morphology, coloration, and breeding phenology. We present a distribution-wide survey of mitochondrial DNA variation in the Little Penguin to document phylogeographic relationships and genetic structuring and to test for concordance with intraspecific taxonomy. Phylogeographic structuring was absent among Australian colonies (27 localities, 94 individuals), but the distribution of haplotypes among colonies was significantly nonrandom (ϕST = 0.110, P < 0.01). The Australian individuals exhibited close phylogenetic relationships with a subset of New Zealand birds (4 localities, 22 individuals), whereas the remaining New Zealand birds (20 localities, 106 individuals) were phylogenetically distinct, with ≥7% sequence divergence, and exhibited greater levels of genetic variation and geographic structuring (ϕST = 0.774, P < 0.05). These patterns are consistent with earlier suggestions of an origin in New Zealand followed by recent colonization of Australia and back-dispersal to New Zealand. Extinction and re-establishment processes may have been important factors in the development of genetic structuring across a range of spatiotemporal scales. The genetic data are consistent with suggestions that a single subspecies exists in Australia, but not with the subspecies distributions within New Zealand that have been suggested on the basis of morphology and coloration.

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The transport of water and ions across mimicked nanotube membranes with pseudo atoms is studied using molecular dynamics simulations under equilibrium conditions and hydrostatic pressure. Different pore surface properties are constructed by assigning partial charges on the sites of specified atoms to explore the influence of charges and polarity. The energetics of water and ion transports through the nanopores was calculated to evaluate their filterability to water. The simulation results show that the free energy barriers to water and ion conductions much depend on the charges at the pore entrance and the dipole within the pore. The membranes with hydrophobic pores and negatively charged entrances would be very efficient in the water transport and ion rejection. The charges and dipoles of the pore wall and the aligned dipoles of water molecules in the pore can create a significant force on ions.

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Pre- and early puberty seem to be the most opportune times for exercise to  improve bone strength in girls, but few studies have addressed this issue in boys. This study investigated the site-, surface-, and maturity-specific exercise-induced changes in bone mass and geometry in young boys. The osteogenic effects of loading were analyzed by comparing the playing and nonplaying humeri of 43 male pre-, peri-, and postpubertal competitive tennis players 10-19 yr of age. Total bone area, medullary area, and cortical area were determined at the mid (40-50%) and distal humerus (60-70%) of both arms using MRI. Humeral bone mass (BMC) was derived from a whole body DXA scan. In prepubertal boys, BMC was 17% greater in the playing compared with nonplaying arm (p < 0.001), which was accompanied by a 12-21% greater cortical area, because of greater periosteal expansion than medullary expansion at the midhumerus and periosteal expansion associated with medullary contraction at the distal humerus. Compared with prepuberty, the side-to-side differences in BMC (27%) and cortical area (20-33%) were greater in peripuberty (p < 0.01). No differences were found between peri- and postpuberty despite longer playing history in the postpubertal players.The osteogenic response to loading was greater in peri- compared with prepubertal boys, which is in contrast with our previous findings in girls and may be caused by differences in training history. This suggests that the window of opportunity to improve bone mass and size through exercise may be longer in boys than in girls.

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While there has been research into the provision of ‘distance’ and ‘off-campus’ education, both in relation to technology and to curriculum, little attention has been given to the experiences of students studying in geographically remote locations, where the remoteness has been an aspect of investigation. This study aimed to investigate the experiences of such students, and to suggest strategies to support them. The students recruited for this project were undergraduate and postgraduate students from remote locations around Australia who had studied at Deakin University between 2003 through 2007. They were interviewed by telephone. The three key issues identified by participants were a sense of isolation, the attitudes and knowledge of the teaching staff; and students’ knowledge and use of learning technologies.

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In contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance [> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement - ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directIn contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance (> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement – ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directed movements need not be very different from those of their temperate counterparts.ed movements need not be very different from those of their temperate counterparts.

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The 1996 Johnson stakeholder review of Australian engineering education recommended the development of a number of broadly defined attributes in all engineering graduates. The Institution of Engineers, Australia (now Engineers Australia) responded swiftly by switching the focus of its engineering course accreditation requirements from course content to graduate attribute outcomes. To maximise the effectiveness of this approach to the mechanical engineering discipline a clear understanding of the relative significance of a more detailed range of attributes to Australian industry is essential, yet the scope of the mechanical engineering profession is broad and views of individual practitioners contributing to debate on attribute requirements are largely influenced by their own often unique professional formation. The research presented in this thesis is unique in using a role based analysis of the relative significance of an extensive range of attributes considered relevant to Australian mechanical engineers. The study covers the six industries found to employ the greatest number of Australian mechanical engineers. The significance of these attributes in the core mechanical engineering roles of each industry are weighted according to the numbers of mechanical engineers employed in those roles. These attribute significance profiles are considered in the context of a study of the formative development of the profession under the extensive influence of 19th and 20th century UK and US practices and recent momentous changes in engineering employment and formation. A wide range of appropriate teaching strategies to develop the most significant attributes through proximal and distance learning are explored and a brief account of the candidate’s work in developing and assessing the use of technology to enhance flexible learning in the field of engineering education is also included in this thesis. Whilst major areas of the mechanical engineers knowledge base are considered as part of the main study, further case study based research is presented to assess in more detail the knowledge base requirements for Australia’s best performing manufacturing industry by ‘industry value added’ - Food, Beverage and Pharmaceuticals and as such provides an indication of the relevance of the content base of Australian mechanical (as well as chemical and electrical) engineering degree programs to an Australian industry sector.

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The author's ethnographic study of a professional development program for managers and aspiring managers taught at a distance intends to make a substantial contribution to both the theory and practice of continuing education for professionals. The study focused on a group of Deakin University Master of Business Administration (MBA) participants and their experiences of the final two years of the program. Theorising on the professional development experience was based on data gathered from the direct observation of participants working in their study groups and at residential schools. Moreover, data drawn from end-of-year interviews with participants and discussions with MBA teachers also contributed to the theorising process. Theorising spanned a broad set of interactions encompassing participants' formal educational, professional and personal worlds. The thesis is devoted to two aspects of the professional development experience, namely: participants' interactions in their study groups and at residential schools; and participants' attempts to grow and develop as competent professional practitioners during their MBA studies. Interactions with key learning contexts orchestrated by the teaching institution (i.e. study groups and residential schools) are grounded in an analysis of the changing group cultures observed to accommodate the different educational demands of the program. Group interaction on a broader scale is also analysed in the context of the residential schools. The residential school provided a powerful forum for the development of participant activism over the future development of the MBA program. The analysis of the study groups in action led the author to identify the key characteristics of effective educational work groups. The implications of the success of these essentially egalitarian and leaderless groups for the formation of self-managed groups in the workplace is examined. On the matter of professional development, the author reveals the relationships between the nature of participants' jobs, their search for professional integration, their stage of professional empowerment, the strategies they pursued either to empower themselves or others in their organisations and the barriers which were encountered in the pursuit of empowerment. Dramatic examples of professional disempowerment are analysed indicating that interaction between formal off-the-job learning and professional practice in the workplace is not necessarily a smooth and positive experience. The group of participants studied are seen to be heterogeneous in relation to the above factors characterising professional development The implications of the theorising are considered in relation to professional pedagogies, assessment strategies and distance education. Distance education is seen to socially construct the roles of both teachers and students in the educational process. Specifically, teachers are seen to be somewhat marginalised during the program in use whereas the participants are located at the centre of the educational experience. The primacy of participants in the educational process is highlighted through the growing reliance on self-and peer-group assessment skills as participants progressed through the program. It is argued that the teaching institution should encourage and maintain the development of these skills as they represent a major learning outcome of the professional development experience, i.e. the ability to engage in the process of critical self-reflection and informed action.

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This study focuses on the experiences of a group of educators engaged in a professional development program by distance education in Papua New Guinea. The participants in this study have been keeping professional journals, for periods of up to three years, about their experiences of distance education. Their discourses have been used to form a ‘connected group’ of research participants, who use an action framework to focus on problematic issues surrounding distance education in Papua New Guinea. It is a piece of research, framed by critical theory, and characterised by participation, collaboration, reflexivity, reciprocity and empowerment. The process of the study is based in dialogue, and takes the view that research is constituted of a transformative perspective, which alters the way research participants understand the multiple realities in which they live and work, arid ultimately results in improvements in their lived experiences. The nature of the methodology privileges Voice' and a discourse of difference from each participant which contributes to the problematic nature of the study. The study has concerned itself, increasingly, with issues of power and control in the research process, and this has resulted in significant changes in the research as participants have become more conscious of issues such as distance, dialogue and difference. The study has evolved over a period of time in significant ways, and evidence is available that teachers in Papua New Guinea, despite structural and pedagogical barriers, are critically reflective and are able to transform their practice in ways which are consistent with social, cultural and political contexts in which they live and work. A number of 'local1 theories about research and distance education in Papua New Guinea are developed by the participants as they become informed about issues during the research. The practice of distance education and professional development, at personal and institutional levels, undergoes reconstruction during the life of the research and the study 'signals' other ways in which distance education and professional development may be reconstructed in Papua New Guinea.