27 resultados para First-principles calculation


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Until now, it has been a challenge both in experiment and in theory to design new superhard materials with high hardness values that are comparable to that of diamond. Here, by using first-principles calculations, we have introduced two new phases for a carbon-rich C-N compound with stoichiometry C3N, which is predicted to be energetically stable or metastable with respect to graphite and solid N2 at ambient pressure. It is found that C3N has a layered structure containing graphitic layers sandwiched with freely rotated N2 molecules. The layer-structured C3N is calculated to transform into a three-dimensional C2221 structure at 9 GPa with sp3-hybridized C atoms and sp2-hybridized N atoms. Phonon dispersion and elastic constant calculations reveal the dynamical and mechanical stability of the C2221 phase of C3N at ambient pressure. Significantly, first-principles ideal strength calculations indicate that the C2221 phase of C3N is a superhard material with an estimated Vickers hardness (∼76 GPa) comparable to that of diamond (60-120 GPa). The present results shed strong light on designing new superhard materials in the C-N system.

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The operation of many nanostructured biomolecular sensors and catalysts critically hinges on the manipulation of non-covalent adsorption of biomolecules on unfunctionalised noble-metal nanoparticles (NMNPs). Molecular-level structural details of the aqueous biomolecule/NMNP interface are pivotal to the successful realisation of these technologies, but such experimental data are currently scarce and challenging to obtain. Molecular simulations can generate these details, but are limited by the assumption of non-preferential adsorption to NMNP features. Here, via first principles calculations using a vdW-DF functional, and based on nanoscale sized NMNPs, we demonstrate that adsorption preferences to NP features vary with adsorbate chemistry. These results show a clear distinction between hydrocarbons, that prefer adsorption to facets over edges/vertices, over heteroatomic molecules that favour adsorption onto vertices over facets. Our data indicate the inability of widely used force-fields to correctly capture the adsorption of biomolecules onto NMNP surfaces under aqueous conditions. Our findings introduce a rational basis for the development of new force-fields that will reliably capture these phenomena.

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One of the recommended principles for classroom practice from the Digital Rhetorics Project is "teachers first", emphasising the need to prioritise the needs of teachers in learning new technologies and understanding their relationship to literacy education (Lankshear, Green, & Snyder, 2000), p.121). While most of my pre-service English Education students use digital technologies for their own purposes and understand the benefits of doing so, it is not always straightforward as to how technology can be effectively utilised in their classroom and for what purposes. This paper reports on work conducted with pre-service English Education teachers in an elective unit that focuses upon digital technologies in secondary classrooms. Using Green's 3D model of literacy as a way of understanding the complex interrelationships between the cultural, critical and operational aspects of literacy, the students experiment with digital technologies such as mobile phones, wikis and blogs.

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This guide has been written for people who are new to tutoring in the Faculty of Economics and Commerce at the University of Melbourne. It is one of a number of teaching and related guides provided by the Teaching and Learning Unit (TLU).
The guide is intended to be a useful source of ideas and advice for good tutoring practice, based on sound educational principles and research.

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The professional landscape in public relations is changing as new communication and social networking technologies are integrated into day-to-day professional practice. Whilst adoption of such technologies by public relations practitioners is certainly on the increase, their use can still be regarded as limited and application experimental to some degree. However, few could argue that these technologies will be increasingly important to public relations practice in coming years.
In this context, public relations educators must strive to deliver a contemporary curriculum reflective of industry expectations and best practice principles but which also provides students with exposure to new communication contexts and technologies.

The advent of persistent virtual worlds generated by Massively Multiplayer Online Role Playing Games (MMORPGs) and Collaborative Virtual Environments (CVEs) offer new realms for public relations practitioners and educators alike. Virtual worlds potentially provide public relations educators with novel but relevant training grounds for their students. These 3D worlds offer dynamic and authentic learning environments which have the capability to foster deep learning and engender a sense of community within a student cohort in a way that many computer-mediated classrooms sadly lack.

This paper will present the experiences of two tertiary educators’ journey towards a conceptual understanding of the persistent virtual world, Second Life, from a teacher perspective. The paper argues that the successful adoption of new online technologies like Second Life need not be inhibited by preferences for technology or prior ICT skills as long as teaching staff are given the necessary support and training by their institutions coupled with opportunity for familiarisation and experimentation.


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This thesis argues that one type of multinational entity – the multinational bank – poses particularly significant challenges to the international tax regime in terms of its current profit allocation rules. Multinational banks are a unique subset of multinational entities, and as a consequence of their unique traits, the traditional international tax regime foes not yield an optimal interjurisdictional allocation of taxing rights. The opportunity for tax minimisation, achievable because of the unique traits, and realised through exploitation of the traditional source and transfer pricing regime, results in a jurisdictional distribution of taxing rights which does not reflect economic reality. There are two distinct ways in which the traditional international tax regime fails to reflect economic activity. The first way that economic activity may not be reflected in the distribution of the taxing rights to income from multinational banking is through the application of traditional source rules. The traditional sources rules allocate income where transactions are completed rather than where the intermediation services are arranged. As a result of their unique commercial role as financial intermediaries, by separating intermediary economic activity from legal transactions with third parties, multinational banks may distort the true location of the activity giving rise to income. The second way in which the traditional tax regime may fail to reflect economic activity is through the traditional transfer pricing regime requiring related or internal transaction to be undertaken at an arm’s length price. The arm’s length pricing requirement is theoretically deficient in its failure to recognise the highly integrated nature of multinational banking. In practice, the arm’s length pricing requirement is also difficult, if not impossible, to apply to multinational banks because of the requirement of comparability. The difficulties associated with the current model have resulted in a subtle move by multinational banks towards global formulary apportionment. This thesis concludes that, for the international taxation of multinational banks, the current source regime should be replaced with a system that allocates profits for tax purposes on the basis of income source, with source determined using a unitary taxation or global formulary apportionment system. It is argued that global formulary apportionment is a theoretically superior model that provides both jurisdiction to tax and allocated profits on the basis of the economic activity that generates the income.

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The substantive field of the thesis is the sociology of distance education. The issues investigated centre on the relationship between off-campus students and the institutions of higher education with which they enrol, in which the first year experience is construed as an encounter between the students’ personal contexts and institutional cultures. A theoretical framework is constructed which synthcsises elements of phenomenology, hermeneutics and feminist theory. The author reports research into the way a small sample of people experienced off-campus study. The students selected resided in Victoria, Australia, and were enrolled with one of two Victorian tertiary institutions: the (then) Gippsland Institute of Advanced Education and Deakin University. Using a case study approach, the subjective experiences of the students were studied by means of a series of interviews which took place at their homes or places of employment in the period January 1988 to November 1989. Methodological issues relating to the application of hermeneutic principles to the use of interviews in educational research are explored. The results of the interpretation of the interview material are presented in terms of an integrationist model of socialisation. The thesis argued is that certain theoretical and practical issues in distance education are best understood as social and cultural phenomena rather than as technical problems. The implications of the findings about the effects of gender and culture on student experience are discussed in relation to the issues of access and equity, student support, and models of teaching and learning.

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Most science educators and researchers will agree that the laboratory experience ranks as a major factor that influences students’ attitudes to their science courses. Consequently, good laboratory programs should play a major role in influencing student learning and performance. The laboratory program can be pivotal in defining a student's experience in the sciences, and if done poorly, can be a major contributing factor in causing disengagement from the subject area. The challenge remains to provide students with laboratory activities that are relevant, engaging and offer effective learning opportunities.

The Advancing Science by Enhancing Learning in the Laboratory (ASELL) project has developed over the last 10 years with the aim of improving the quality of learning in undergraduate laboratories, providing a validated means of evaluating the laboratory experience of students and effective professional development for academic staff. After successful development in chemistry and trials using the developed principles in physics and biology, the project has now expanded to include those disciplines. This paper will discuss the activities of ASELL and provide a report about the first ASELL science workshop held at the University of Adelaide in April 2010, present some views of academic and student delegates, and make comparisons with other workshops.
Introduction

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Equity has a long history in education. When compulsory schooling was first introduced in industrialising nations in the mid 1800s, many advocates saw it as a way of improving the circumstances of the poorest and most disadvantaged in their communities. But access to schooling did not prove to be the great equaliser that some had hoped. Instead, it became central in the reproduction of social and economic inequalities (Bourdieu & Passeron 1977). High academic achievement became highly correlated with high socioeconomic status, and vice versa (Teese & Polesel 2003). In Australia, the Karmel Report (1973) proved to be a watershed moment in naming the equity problem in schooling and, among other things, gave rise to the Disadvantaged Schools Program (DSP): an attempt to level the playing field albeit by ‘running twice as hard’ (Connell at al. 1991). Almost two decades later, A Fair Chance for All (1990) signalled official concern for equity in Australian higher education. While access to university was not to be universal, it was to be equitable; all social groups in the Australian population were to be proportionally represented among its university students. Today, Australia is still grappling with the inequities in its schooling and higher education systems, highlighted by renewed interest by governments to address the issues. Although not of the same order of magnitude, there now appears to be an emerging policy agenda around equity in VET. Has equity’s time come for VET? This paper canvasses the history of equity in Australian schooling and higher education, with a view to drawing out principles to inform a rejuvenated equity agenda in vocational education and training.

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In this paper I want to make the case for creating spaces in tertiary education for marginalised Australians. And I want to distinguish this from creating places for them. The reason for focusing on the first rather than the second is that I think we have been better at creating places than spaces for students from equity groups, although our track record in relation to their place in tertiary education is not very good either.

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BACKGROUND: Treatment strategies for mental disorders may vary according to illness stage. However no data currently exist to guide treatment in first episode psychotic mania. The aim of this study was to compare the safety and efficacy profile of chlorpromazine and olanzapine, as add-on to lithium, in patients with a first episode of psychotic mania, expecting better safety profile and adherence to olanzapine but similar efficacy for both treatments. METHODS: Data from 83 patients were collected in an 8-week randomised controlled trial on clinical variables, side effects, vital signs, and weight. Analyses of treatment differences over time were based on intent-to-treat principles. Kaplan-Meier estimated survival curves were used to analyse time-to-event data and mixed effects models repeated measures analysis of variance were used to determine treatment group differences over time on safety and efficacy measures. RESULTS: Ethics committee approval to delay informed consent procedure until recovery from the acute episode allowed the inclusion of 83 patients highly representative of those treated in the public sector. Contrary to our hypotheses, safety profile of both medications was similar. A signal for higher rate (P=.032) and earlier occurrence (P=.043) of mania remission was observed in the olanzapine group which did not survive correction for multiple comparisons. CONCLUSIONS: Olanzapine and chlorpromazine have a similar safety profile in a uniquely representative cohort of patients with first episode psychotic mania. The possibility for a greater impact of olanzapine on manic symptoms leading to earlier remission of the episode needs exploration in a large sample.

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This paper presents the results of domestic Chinese undergraduate engineering course taught by international Australasian teaching staff. The project is a part of a teaching collaboration between Deakin University and Wuhan University of Science and Technology. The cohort of students from Wuhan was a freshman undergraduate engineering course in mechanical engineering. The particular subject was a freshman engineering-materials course taught in English. The course covered an introduction to material-science principles and practices. A survey was used for evaluating student perceptions. It is aimed that this study will help academics from Deakin University to better understand student experiences, and to identify the current challenges and barriers faced in student learning. Analysis of the survey has shown that 90% of students agreed that they were motivated to learn and achieve the learning goals through this collaborative program. Around 90% of students found that group-based practical activities were helpful in achieving learning goals. Overall, 90% of students strongly agreed they were satisfied with the method of teaching.