348 research outputs found

    Tricritical behaviour of Ising spin glasses with charge fluctuations

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    We show that tricritical points displaying unusal behaviour exist in phase diagrams of fermionic Ising spin glasses as the chemical potential or the filling assumes characteristic values. Exact results for infinite range interaction and a one loop renormalization group analysis of thermal tricritical fluctuations for finite range models are presented. Surprising similarities with zero temperature transitions and a new T=0T=0 tricritical point of metallic quantum spin glasses are derived.Comment: 4 pages, 1 Postscript figure, minor change

    RNA helicase A interacts with divergent lymphotropic retroviruses and promotes translation of human T-cell leukemia virus type 1

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    The 5′ untranslated region (UTR) of retroviruses contain structured replication motifs that impose barriers to efficient ribosome scanning. Two RNA structural motifs that facilitate efficient translation initiation despite a complex 5′ UTR are internal ribosome entry site (IRES) and 5′ proximal post-transcriptional control element (PCE). Here, stringent RNA and protein analyses determined the 5′ UTR of spleen necrosis virus (SNV), reticuloendotheliosis virus A (REV-A) and human T-cell leukemia virus type 1 (HTLV-1) exhibit PCE activity, but not IRES activity. Assessment of SNV translation initiation in the natural context of the provirus determined that SNV is reliant on a cap-dependent initiation mechanism. Experiments with siRNAs identified that REV-A and HTLV-1 PCE modulate post-transcriptional gene expression through interaction with host RNA helicase A (RHA). Analysis of hybrid SNV/HTLV-1 proviruses determined SNV PCE facilitates Rex/Rex responsive element-independent Gag production and interaction with RHA is necessary. Ribosomal profile analyses determined that RHA is necessary for polysome association of HTLV-1 gag and provide direct evidence that RHA is necessary for efficient HTLV-1 replication. We conclude that PCE/RHA is an important translation regulatory axis of multiple lymphotropic retroviruses. We speculate divergent retroviruses have evolved a convergent RNA–protein interaction to modulate translation of their highly structured mRNA

    The Ubiquitous Inflaton in String-Inspired Models

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    A string theory based inflationary model is developed where the inflaton interacts with a multitude of massive string level states causing dissipation of vacuum energy. Inflation terminates in a warm Universe without the need for reheating.Comment: In Press Physical Review Letters 1999, modified titl

    Impact of student approaches to ALURE: 'Swimming lessons' in the undergraduate laboratory

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    Pedwell, R., Green, M., Lawrie, G., Myatt, P., Wang, J., Worthy, P., Zimbardi, K., Rowland, S. Presenting Author: Rhianna Pedwell This study investigated student-reported experiences in Authentic Large-scale Undergraduate Research Experiences (ALUREs) and in traditional laboratory-based practical sessions (LEAPS). Background Engaging undergraduate students in research is considered essential for a tertiary science education; and for producing prepared, informed graduate scientists. Existing undergraduate research experience models have been shown to confer a broad array of student benefits, however they also have limitations of scale that prevent large numbers of students engaging in undergraduate research. We are using ALURE to massify the opportunity for undergraduate students to participate in research and to explore it as a potential part of their future study and career plans. Aims This study aimed to record student perceptions of their learning and development during ALUREs, and determine the aspects of ALURE that students report as 'helps and hindrances' for this learning and development. The aim of the OLT-funded ALURE Project is to give information to academics who want to engage their undergraduates in integrated research experiences. We aim to use our data to develop good practice guidelines for ALURE implementation, with a particular focus on enhancing the student experience. Description of Educational Model ALUREs are designed to give whole-course cohorts of undergraduate students a chance to take part in course-based research experiences throughout their education. An ALURE is implemented as part of a regular undergraduate course; the students work with peers, tutors, and an engaged researcher to generate and communicate original, meaningful data. We have conducted ALURE experiences for up to four hundred students at a time in one course. This year, ALUREs were implemented in a multitude of disciplines, from Biochemistry to Microbiology to Nanotechnology. Each ALURE was developed to fit the implementers' specific course, discipline, and learning objectives. Design and Methods This phenomenological, ethnographical study drew from both qualitative and quantitative sources of student-reported experiences. Students from four Australian universities were invited to share their experiences in ALUREs or LEAPS in the form of surveys, written reflections, and qualitative interviews. Survey data was statistically analysed to measure changes in skills acquisition, and development of attitudes towards learning and future plans. Written reflections and interview transcripts were coded to find themes consistent with a student gains framework as described in Hunter et al. (2007). These gains are a core component of the Ethnography and Evaluation Research Undergraduate Research Student Self-Assessment (URSSA) survey (Hunter et al., 2009), part of our post-survey. Also included were themes relating to ALURE design and implementation. Results From our initial data analyses, we anticipate that we will be able to present findings indicating student gains aligned with those in the URSSA framework, including increased awareness of research practice, skills acquisition and preparedness for future pathways (Hunter et al., 2007; Hunter et al., 2009). Student assessments of support within and authenticity of ALUREs will also be reported. References: Hunter, A-B., Laursen, S. L., & Seymour, E. (2007). Becoming a Scientist: The Role of Undergraduate Research in Students' Cognitive, Personal, and Professional Development. Science Education, 91(1), 36 - 74. http://onlinelibrary.wiley.com/doi/10.1002/sce.20173/abstract Hunter, A-B., Weston, T. J., Laursen, S. L., & Thiry, H. (2009). URSSA: Evaluating Student Gains from Undergraduate Research in the Sciences. Council on Undergraduate Research Quarterly, 29(3), 15 - 19. http://www.cur.org/publications/cur_quarterly_index_online_search/?F_Sort=PostDate&SearchBy=Title&SearchField=URSSA&Boolean=AND&SortOrder=DES

    Report of a workshop on technical approaches to construction of a seafloor geomagnetic observatory

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    This report considers the technical issues on sensors, data recording and transmission, control and timing, power, and packaging associated with constricting a seafloor geomagnetic observatory. Existing technologies either already in use for oceanographic purposes or adapted from terrestral geomagnetic observatories could be applied to measure the vector magnetic field components and absolute intensity with minimal development. The major technical challenge arises in measuring absolute direction on the seafloor because terrestral techniques are not transferrable to the deep ocean. Two solutions to this problem were identified. The first requires the development of an instrument which measures the instantaneous declination and inclination of the magnetic field relative to a north-seeking gyroscope and the local vertical. The second is a straightforward extension of a precision acoustic method for determining absolute position on the seafloor.Funding was provided by the National Science Foundation under grant EAR94-21712 and the National Aeronautics and Space Administration

    Investigating factors that support and challenge in implementing authentic research experiences for undergraduates

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    KEYWORDS: undergraduate, research experience, course integrated, implementation, case study, science This study investigated the implementer experience of introducing an Authentic Large Scale Undergraduate Research Experience (ALURE) into 7 science courses in three Australian tertiary institutions. The results will be of value to tertiary science educators who are interested in giving the opportunity to experience the benefits of research participation to a larger number of their undergraduate students. BACKGROUND The integration of research experiences into undergraduate curricula is of special importance in the fields of STEM. Engaging undergraduate students in research is considered essential for a tertiary science education, informing students future career course and increasing student retention. Our project is supporting the introduction of an ALURE (Authentic Large Scale Undergraduate Research Experience) practical into several undergraduate science courses. These ALURE practicals are designed to overcome the cohort size limits of the research internship model primarily due to their integration to the course based practical session. ALUREs are designed to give whole cohorts of students a chance to take part in an undergraduate research experience throughout their education; giving students an idea of what real research is before they enter into post-graduate life. Our team has previously documented several ALURE practicals reported in several papers (Rowland, Lawrie, Behrendorff & Gillam 2012; Wang, Schembri, Ramakrishna, Sagulenko & Fuerst, 2012); this allows us to act as mentors to new ALURE implementers during our OLT-funded Leadership for Excellence Project. AIMS This study aimed to document the experience of implementers during the delivery of an ALURE and determine what factors supported and challenged them during this time. The aim of the ALURE Project is to provide leadership and mentoring to any academics wanting to engage their undergraduates in course integrated research experiences. We aim to utilise this data to amend and improve current guidelines of ALURE implementation to define a best practice for the future. DESCRIPTION OF STUDY This year, ALUREs were implemented at various tertiary institutions nationally in courses covering a broad range of scientific disciplines including biochemistry, nanotechnology and microbiology. The implementers of these programs are the topic of this study and their experiences provide deeper insight into the potential hurdles to integrating a large-scale course based URE. Implementers that were investigated included course coordinators, laboratory demonstrators and preparation staff. The study included 7 different science courses across 4 Australian tertiary institutions. DESIGN AND METHODS This narrative and grounded theory mixed methods study drew from qualitative sources of information in the form of recorded interviews with implementers from 4 Australian universities invited to share their experience. Transcripts were coded to find common themes in order to discover the factors that challenged and supported the introduction of ALURE into their course. RESULTS Preliminary data shows that currently the main challenging factor is the time taken to implement these practicals into the course for the first iteration and that the primary supporting factor is the support of a change champion in the organisation. Based on interviews we have also developed models of ALURE implementation, which show how each implementation was organised. These models demonstrate the generalisability of the ALURE model to various fields of study and institutions and will be of benefit to anyone who is contemplating ALURE implementation
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