6,918 research outputs found

    Shifting sands: the narrative construction of early career aboriginal teachers' professional identities at the cultural interface

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    This study explores issues facing early career Aboriginal teachers as they construct and enact their personal, professional and situated identities when learning to teach. Narrative constructions of identity simultaneously illuminate and challenge dominant discourses about Aboriginal teachers as they take up, resist and/or reject these discourses. The role of Aboriginality is mediated by factors such as lived experience, positioning of and by the teachers and school contexts. These issues are explored through the theoretical perspectives of Foucault, Bourdieu and Nakata. Like shifting sands, identity construction and teaching work can be unstable terrain, requiring complex contextualised understandings, skills and dispositions. Participants are pre-service Aboriginal teachers in an away-from-base secondary Aboriginal Studies teacher education program at the University of Sydney. They are mature-aged with varying levels of experience of formal education and living in Aboriginal communities. Using narrative methodology, eleven in-depth conversational interviews followed by two focus groups revealed emerging storylines and themes and four participants were identified for further interviews to collaboratively construct the final narratives. This approach privileged participant voices and created spaces to articulate the tacit knowledge and understandings that contribute to the development of a professional identity drawn from personal, professional, cultural and contextual sources. Three themes emerged: discourses of Aboriginality, narratives of belonging, and conceptualising a pedagogical cultural identity. The implications of these themes bring focus to pre-service and in-service teacher professional learning based on valuing Aboriginal community engagement. When nurtured early in a teacher’s career, relationships serve a socio-cultural and political role that contribute significantly to the development of agentic and resilient identities at the cultural interface

    Iterative evolution of digitate planktonic foraminifera

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    Digitate shell morphologies have evolved repeatedly in planktonic foraminifera throughout the Cretaceous and Cenozoic. Digitate species are usually rare in fossil and modern assemblages but show increased abundance and diversity at times during the Cretaceous and mid- dle Eocene. In this paper we discuss the morphology and stratigraphic distribution of digitate planktonic foraminifera and establish the isotopic depth ecology of fossil ones to draw parallels with modern counterparts

    Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

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    Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth’s past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2

    Unquenching the scalar glueball

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    Computations in the quenched approximation on the lattice predict the lightest glueball to be a scalar in the 1.5-1.8 GeV region. Here we calculate the dynamical effect the coupling to two pseudoscalars has on the mass, width and decay pattern of such a scalar glueball. These hadronic interactions allow mixing with the qqq \overline q scalar nonet, which is largely fixed by the well-established K_0^*(1430). This non-perturbative mixing means that, if the pure gluestate has a width to two pseudoscalar channels of ~100 MeV as predicted on the lattice, the resulting hadron has a width to these channels of only ~30 MeV with a large eta-eta component. Experimental results need to be reanalyzed in the light of these predictions to decide if either the f_0(1500) or an f_0(1710) coincides with this dressed glueball.Comment: 12 pages, LaTex, 3 Postscript figure

    Droplets Transport in a Microfluidic Chip for In Vitro Compartmentalisation

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    In vitro compartmentalisation is an emerging technology for protein evolution and selection. In this presentation, we will report the development of a microdrop-based microfluidic platform for in vitro enzyme evolution and selection applications. A microfluidic chip has been developed and fabricated using the standard photolithography method in conjunction with electroplating and hot embossing techniques. A cross channel geometry was used to focus liquid flows for droplet generation. To realize on-chip compartmentalised bio-reactions, two droplet generators were fabricated on the same chip. Experiments have been carried out to measure droplet size, generation rate and speed using a photographic technique. Droplet size was found to be decreasing with increasing focusing oil flow rate for a given aqueous phase flow rate. When two droplet generators are used in the same chip, the droplets may be generated asynchronously due to different flow conditions. If the droplets were significantly smaller than channel size, the faster moving droplets could pass the slower moving droplets with little coalescence. If the droplets were of the channel size, the faster moving droplets would break or fuse with the slow droplets. To achieve high rate of droplet fusion, active control should be in place for synchronous generation and fusion

    Evaluating Diet Composition of Pronghorn in Wind Cave National Park, South Dakota

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    The pronghorn (Antilocapra americana) was reintroduced into Wind Cave National Park (WCNP), South Dakota, in 1914, and thus, has inhabited the Park for nearly a century. During the 1990\u27s, a decline in the population raised concern for the continued existence of pronghorn inside WCNP; an investigation into the observed decline was initiated. Primary objectives of our study were to evaluate diet composition and forage selection by pronghorn in WCNP. Microhistological analysis was conducted on 58 fecal samples collected opportunistically from pronghorn during 2002. Blue grama (Bouteloua gracilis), common juniper (Juniperus communis), and northern bedstraw (Galium boreale) were identified as major seasonal food items, representing 14.6, l 0.6, and 6.5 % of the annual diet, respectively. Annual diets of pronghorn in WCNP included 41.5% grasses, 31.1% shrubs, and 27.4% forbs. Total forage production in WCNP was 2% grass, 4% shrubs, and 23% forbs. Results indicated strong dietary selection by pronghorn for shrubs

    Exact Calculation of the Spatio-temporal Correlations in the Takayasu model and in the q-model of Force Fluctuations in Bead Packs

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    We calculate exactly the two point mass-mass correlations in arbitrary spatial dimensions in the aggregation model of Takayasu. In this model, masses diffuse on a lattice, coalesce upon contact and adsorb unit mass from outside at a constant rate. Our exact calculation of the variance of mass at a given site proves explicitly, without making any assumption of scaling, that the upper critical dimension of the model is 2. We also extend our method to calculate the spatio-temporal correlations in a generalized class of models with aggregation, fragmentation and injection which include, in particular, the qq-model of force fluctuations in bead packs. We present explicit expressions for the spatio-temporal force-force correlation function in the qq-model. These can be used to test the applicability of the qq-model in experiments.Comment: 15 pages, RevTex, 2 figure

    “At First I Wouldn’t Talk so Much…”: Coaching and Associated Changes in Language-Supportive Self-Efficacy among Infant/Toddler Educators

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    Developing strong language and communication skills in the first years of life provides young children with a foundation for a number of positive outcomes, including school readiness, early literacy skills, and self-regulation. High quality language supports in early childhood education programs are key to this development. Part of providing these high-quality language supports involves educators perceiving themselves as efficacious in their capability to support young children’s language development. Using mixed methods, this study examines the extent to which there are changes in educators’ language-focused self-efficacy after participating in professional development program focused on promoting infant/toddler language development. We examine the changes across two groups: (1) educators who participated in a workshop focused on infant/toddler language development and (2) educators who participated in the same workshop plus one-on-one practice-based coaching. Results suggest that participation in the workshop plus coaching compared to the workshop alone was related to greater growth in self-efficacy in language modeling and instructional practices. In follow-up interviews, coached educators reported on their perceptions of impact of the program on their practices and interactions with children. Implications for future research and practice are discussed

    Sub-threshold depressive symptoms and brain structure: A magnetic resonance imaging study within the Whitehall II cohort

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    BACKGROUND: Late-life sub-threshold depressive symptoms (i.e. depressive symptoms that do not meet the criteria for a diagnosis of major depressive disorder) are associated with impaired physical health and function, and increased risk of major depressive disorder. Magnetic resonance imaging (MRI) studies examining late-life major depressive disorder find structural brain changes in grey and white matter. However, the extent to which late-life sub-threshold depression is associated with similar hallmarks is not well established. METHODS: Participants with no history of major depressive disorder were selected from the Whitehall Imaging Sub-Study (n=358, mean age 69±5 years, 17% female). Depressive symptoms were measured using the Centre for Epidemiological Studies Depression Scale (CES-D) at three previous Whitehall II Study phases (2003-04, 2007-09 and 2012-13) and at the time of the MRI scan (2012-14). The relationships between current and cumulative depressive symptoms and MRI brain measures were explored using Voxel-Based Morphometry (VBM) for grey matter and Tract Based Spatial Statistics (TBSS) for white matter. RESULTS: Current sub-threshold depressive symptoms were associated with significant reductions in fractional anisotropy and increases in axial and radial diffusivity. There were no significant relationships between current depressive symptoms and grey matter measures, or cumulative depressive symptoms and MRI measures. LIMITATIONS: The prevalence (10%) of sub-threshold depressive symptoms means that analyses may be underpowered to detect subtle differences in brain structure. CONCLUSIONS: Current sub-threshold depressive symptoms are associated with changes in white matter microstructure, indicating that even mild depressive symptoms are associated with similar MRI hallmarks to those in major depressive disorder
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