44,304 research outputs found

    On the pulse of change: the new beat of special education in higher education

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    The roles and responsibilities of special educators in both special and regular school settings are changing rapidly. More than two decades ago the move towards more inclusive practices disrupted the traditional, niche separatism of special educators to the extent that they are now an integral part of the regular school teaching staff. Today the broad agenda to facilitate access and participation for all students in education, not just students with disabilities, influences the roles and responsibilities of special educators. This article briefly identifies some of the generic pulses that are moving the special education profession from a focus on low incidence disabilities towards a more comprehensive approach to inclusion, school responsiveness and individualised learning pathways. From the foundation of inclusive practice, this paper will describe how a qualitative study was used to understand the changing roles and responsibilities of special educators. A case study analysis of 17 schools formed the basis of the investigation. Principals, lead teachers in special education and special education teachers were asked to identify trends and priorities in special education and also to identify rewards and challenges in their jobs. Further cross referencing with teacher and special educator standards, a focus group, a stakeholder group and research in the field increased the opportunity for academics and special educators to critically reflect on the emerging demands placed on special educators and the attributes that are needed to be professionally effective

    Bayesian Estimation of the Discrepancy with Misspecified Parametric Models

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    We study a Bayesian model where we have made specific requests about the parameter values to be estimated. The aim is to find the parameter of a parametric family which minimizes a distance to the data generating density and then to estimate the discrepancy using nonparametric methods. We illustrate how coherent updating can proceed given that the standard Bayesian posterior from an unidentifiable model is inappropriate. Our updating is performed using Markov Chain Monte Carlo methods and in particular a novel method for dealing with intractable normalizing constants is required. Illustrations using synthetic data are provided.European Research Council (ERC) through StG "N-BNP" 306406Regione PiemonteMathematic

    National and international freight transport models: overview and ideas for further development

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    This paper contains a review of the literature on freight transport models, focussing on the types of models that have been developed since the nineties for forecasting, policy simulation and project evaluation at the national and international level. Models for production, attraction, distribution, modal split and assignment are discussed in the paper. Furthermore, the paper also includes a number of ideas for future development, especially for the regional and urban components within national freight transport models

    Collaborative concept mapping: an education research team leveraging their collaborative efforts

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    Collaborative concept mapping (CCM) has been a tool deployed by educators to enhance learning in such situations as primary science classes, supported learning environments and asynchronous computer-mediated learning. Of its outcomes, CCM has produced rich group discussion about ideas and possibilities pertinent to the topic or problem at hand. The majority of research into CCM has been explicitly pointed at enhancing learning. This chapter takes a different tack by reporting on how the authors used CCM to seek understandings of its utility in enabling collaborative research by creating synergies within a research team located in the Faculty of Education at the University of Southern Queensland. The following questions were used to focus the research: • What was the research team’s experience of collaborative concept mapping? • What propositions did the team construct about teamwork and collaboration? • How did the interactions among team members facilitate meaning-making about teamwork and collaboration? The data consisted of this team’s collaborative concept map and recordings of the dialogue during the process of constructing the map. Analysis revealed the team’s emerging propositions about teamwork and collaboration and also contributed understandings of the co-constructed patterns of talk that produced this dynamic map. The chapter concludes that collaborative concept mapping is a useful tool for research and other team development, and possibly for the collaborative conceptualisation of future team research projects

    Baryon mass splittings and strong CP violation in SU(3) Chiral Perturbation Theory

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    We study SU(3)SU(3) flavor-breaking corrections to the relation between the octet baryon masses and the nucleon-meson CP-violating interactions induced by the QCD θˉ\bar\theta term. We work within the framework of SU(3)SU(3) chiral perturbation theory and work through next-to-next-to-leading order in the SU(3)SU(3) chiral expansion, which is O(mq2)\mathcal{O}(m_q^2). At lowest order, the CP-odd couplings induced by the QCD θˉ\bar\theta term are determined by mass splittings of the baryon octet, the classic result of Crewther et al. We show that for each isospin-invariant CP-violating nucleon-meson interaction there exists one relation which is respected by loop corrections up to the order we work, while other leading-order relations are violated. With these relations we extract a precise value of the pion-nucleon coupling gˉ0\bar g_0 by using recent lattice QCD evaluations of the proton-neutron mass splitting. In addition, we derive semi-precise values for CP-violating coupling constants between heavier mesons and nucleons with 30%\sim 30\% uncertainty and discuss their phenomenological impact on electric dipole moments of nucleons and nuclei.Comment: 49 pages. Published versio

    Line Profiles from Discrete Kinematic Data

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    We develop a method to extract the shape information of line profiles from discrete kinematic data. The Gauss-Hermite expansion, which is widely used to describe the line of sight velocity distributions extracted from absorption spectra of elliptical galaxies, is not readily applicable to samples of discrete stellar velocity measurements, accompanied by individual measurement errors and probabilities of membership. We introduce two parameter families of probability distributions describing symmetric and asymmetric distortions of the line profiles from Gaussianity. These are used as the basis of a maximum likelihood estimator to quantify the shape of the line profiles. Tests show that the method outperforms a Gauss-Hermite expansion for discrete data, with a lower limit for the relative gain of approx 2 for sample sizes N approx 800. To ensure that our methods can give reliable descriptions of the shape, we develop an efficient test to assess the statistical quality of the obtained fit. As an application, we turn our attention to the discrete velocity datasets of the dwarf spheroidals of the Milky Way. In Sculptor, Carina and Sextans the symmetric deviations are consistent with velocity distributions more peaked than Gaussian. In Fornax, instead, there is an evolution in the symmetric deviations of the line profile from a peakier to more flat-topped distribution on moving outwards. These results suggest a radially biased orbital structure for the outer parts of Sculptor, Carina and Sextans. On the other hand, tangential anisotropy is favoured in Fornax. This is all consistent with a picture in which Fornax may have had a different evolutionary history to Sculptor, Carina and Sextans.Comment: MNRAS, accepted for publication, minor change

    Extremely Anisotropic Scintillations

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    A small number of quasars exhibit interstellar scintillation on time-scales less than an hour; their scintillation patterns are all known to be anisotropic. Here we consider a totally anisotropic model in which the scintillation pattern is effectively one-dimensional. For the persistent rapid scintillators J1819+3845 and PKS1257-326 we show that this model offers a good description of the two-station time-delay measurements and the annual cycle in the scintillation time-scale. Generalising the model to finite anisotropy yields a better match to the data but the improvement is not significant and the two additional parameters which are required to describe this model are not justified by the existing data. The extreme anisotropy we infer for the scintillation patterns must be attributed to the scattering medium rather than a highly elongated source. For J1819+3845 the totally anisotropic model predicts that the particular radio flux variations seen between mid July and late August should repeat between late August and mid November, and then again between mid November and late December as the Earth twice changes its direction of motion across the scintillation pattern. If this effect can be observed then the minor-axis velocity component of the screen and the orientation of that axis can both be precisely determined. In reality the axis ratio is finite, albeit large, and spatial decorrelation of the flux pattern along the major axis may be observable via differences in the pairwise fluxes within this overlap region; in this case we can also constrain both the major-axis velocity component of the screen and the magnitude of the anisotropy.Comment: 5 pages, 4 figures, MNRAS submitte

    Probing non-spherical dark halos in the Galactic dwarf galaxies

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    We construct axisymmetric mass models for dwarf spheroidal (dSph) galaxies in the Milky Way to obtain plausible limits on the non-spherical structure of their dark halos. This is motivated by the fact that the observed luminous parts of the dSphs are actually non-spherical and Cold Dark Matter (CDM) models predict non-spherical virialized dark halos. Our models consider velocity anisotropy of stars vR2ˉ/vϕ2ˉ\bar{v^2_R} / \bar{v^2_{\phi}}, which can vary with the adopted cylindrical coordinates under the assumption vz2ˉ=vR2ˉ\bar{v^2_z}=\bar{v^2_R} for simplicity, and also include an inclination of the system as a fitting parameter to explain the observed line-of-sight velocity dispersion profile. Applying these models to six of the bright dSphs in the Milky Way, we find that the best-fitting cases for most of the dSphs yield oblate and flattened dark halos, irrespective of assumed density profiles in their central parts. We also find that the total mass of the dSphs enclosed within a spheroid with major-axis length of 300 pc varies from 106M10^6M_{\odot} to 107M10^7M_{\odot}, contrary to the conclusion from spherical models. This suggests the importance of considering shapes of dark halos in mass models of the dSphs. It is also found that dark halos of the Galactic dSphs may be more flattened than N-body predictions, thereby implying our yet incomplete understanding of baryonic and/or non-baryonic dark matter physics in dwarf galaxy scales.Comment: 13 pages, 9 figures, Accepted for publication in Ap

    Effect of multiple episodes of Acute Kidney Injury on mortality:an observational study

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    Background Patients who survive an episode of acute kidney injury (AKI) are more likely to have further episodes of AKI. AKI is associated with increased mortality, with a further increase with recurrent episodes. It is not clear whether this is due to AKI or as a result of other patient characteristics. The aim of this study was to establish whether recurrence of AKI is an independent risk factor for mortality or if excess mortality is explained by other factors. Methods This observational cohort study included adult people from the Tayside region of Scotland, with an episode of AKI between 1 January 2009 and 31 December 2009. AKI was defined using the creatinine-based Kidney Disease: Improving Global Outcomes definition. Associations between recurrent AKI and mortality were examined using a Cox proportional hazards model. Results Survival was worse in the group identified to have recurrent AKI compared with those with a single episode of AKI [hazard ratio = 1.49, 95% confidence interval (CI) 1.37–1.63; P
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