7,350 research outputs found

    Expansive Learning

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    Chapter six explores the concept of ‘expansive learning’ taken from Fuller and Unwin’s (2003) research of apprenticeships where they identified a ‘restrictive- expansive continuum’ that classified the type of learning environment presented in the work place. Crucially, expansive learning encouraged a supportive environment for students to learn higher level skills such as dialogue, problem solving and reflexive forms of expertise. Supportive and collaborative learning environments can instil confidence in the student to develop and the supervisory role (or previously the mentor) is significant to this. The chapter theme of expansive learning is led by the goal to discover what teaching and learning processes can assist all levels of clinical staff in supporting students to move effectively, and in a well-supported way, to the expertise or ‘graduateness’ (Eden, 2014) required at registration and beyond. This was an important foundation of the recent NMC (2017) review. Chapter 2 and 3 have already demonstrated the potential educational role of unqualified staff and peer students who previously have not been officially recognised for coaching learners in practice. With focused and explicit support for their learning, students’ placement experience can be ‘supercharged’ so their learning advances quicker and with greater impact on their long term professional development (Morley, 2018). A model of coaching that emerged from the research study is also presented. Current emphasis in practice learning is placed on the assessment of measurable clinical skills rather than the students’ ability to join these skills holistically in professional practice (Morley, 2015). The ability to be able to teach this type of integration of student performance into the busy clinical practice is more akin to the fluidity of ‘coaching’ rather than ‘teaching’ and this is explored fully within the chapter

    Computer-aided communication satellite system analysis and optimization

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    The capabilities and limitations of the various published computer programs for fixed/broadcast communication satellite system synthesis and optimization are discussed. A satellite Telecommunication analysis and Modeling Program (STAMP) for costing and sensitivity analysis work in application of communication satellites to educational development is given. The modifications made to STAMP include: extension of the six beam capability to eight; addition of generation of multiple beams from a single reflector system with an array of feeds; an improved system costing to reflect the time value of money, growth in earth terminal population with time, and to account for various measures of system reliability; inclusion of a model for scintillation at microwave frequencies in the communication link loss model; and, an updated technological environment

    Towards quantifying the completeness of BDI goals

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    Often, such as in the presence of con icts, an agent must choose between multiple intentions. The level of complete- ness of the intentions can be a factor in this deliberation. We sketch a pragmatic but principled mechanism for quan- tifying the level of completeness of goals in a Belief-Desire- Intention{like agent. Our approach leverages previous work on resource and e ects summarization but we go beyond by accommodating both dynamic resource summaries and goal e ects, while also allowing a non-binary quanti cation of goal completeness

    Cannabis and depression: A twin model approach to co-morbidity

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    Cannabis use disorder (CUD) co-occurs with major depressive disorder (MDD) more frequently than would be expected by chance. However, studies to date have not produced a clear understanding of the mechanisms underlying this co-morbidity. Genetically informative studies can add valuable insight to this problem, as they allow the evaluation of competing models of co-morbidity. This study uses data from the Australian Twin Registry to compare 13 co-morbidity twin models initially proposed by Neale and Kendler (Am J Hum Genet 57:935–953, 1995). The analysis sample comprised 2410 male and female monozygotic and dizygotic twins (average age 32) who were assessed on CUD and MDD using the SSAGA-OZ interview. Data were analyzed in OpenMx. Of the 13 different co-morbidity models, two fit equally well: CUD causes MDD and Random Multiformity of CUD. Both fit substantially better than the Correlated Liabilities model. Although the current study cannot differentiate between them statistically, these models, in combination, suggest that CUD risk factors may causally influence the risk to develop MDD, but only when risk for CUD is high

    Shedding some light on Thismia rodwayi F. Muell. (fairy lanterns) in Tasmania: distribution, habitat and conservation status

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    Thismia rodwayi is a seldom-seen, subterranean plant that occurs in Tasmania, the eastern states of the Australian mainland and New Zealand. Surveys for the species were prompted by a new record from Archers Sugarloaf near Meander in Tasmania's central north. Several new populations of the species were subsequently discovered in wet eucalypt forests dominated by Eucalyptus obliqua, E. regnans, E. delegatensis or E. viminalis, with an understorey dominated by Pomaderris apetala, Bedfordia salicina and/or Olearia argophylla. The species is now known from the Meander, Glen Huon, Little Denison River, Mount Field, Mount Wellington and Ben Lomond areas. Analysis of current information suggests that the listing of T. rodwayi under Schedule 5 (Rare) of the Tasmanian Threatened Species Protection Act 1995 is appropriate

    Witnessing eigenstates for quantum simulation of Hamiltonian spectra

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    The efficient calculation of Hamiltonian spectra, a problem often intractable on classical machines, can find application in many fields, from physics to chemistry. Here, we introduce the concept of an "eigenstate witness" and through it provide a new quantum approach which combines variational methods and phase estimation to approximate eigenvalues for both ground and excited states. This protocol is experimentally verified on a programmable silicon quantum photonic chip, a mass-manufacturable platform, which embeds entangled state generation, arbitrary controlled-unitary operations, and projective measurements. Both ground and excited states are experimentally found with fidelities >99%, and their eigenvalues are estimated with 32-bits of precision. We also investigate and discuss the scalability of the approach and study its performance through numerical simulations of more complex Hamiltonians. This result shows promising progress towards quantum chemistry on quantum computers.Comment: 9 pages, 4 figures, plus Supplementary Material [New version with minor typos corrected.

    Effect of Longitude-Dependent Cloud Coverage on Exoplanet Visible Wavelength Reflected-Light Phase Curves

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    We use a planetary albedo model to investigate variations in visible wavelength phase curves of exoplanets. Thermal and cloud properties for these exoplanets are derived using one-dimensional radiative-convective and cloud simulations. The presence of clouds on these exoplanets significantly alters their planetary albedo spectra. We confirm that non-uniform cloud coverage on the dayside of tidally locked exoplanets will manifest as changes to the magnitude and shift of the phase curve. In this work, we first investigate a test case of our model using a Jupiter-like planet, at temperatures consistent to 2.0 AU insolation from a solar type star, to consider the effect of H2O clouds. We then extend our application of the model to the exoplanet Kepler-7b and consider the effect of varying cloud species, sedimentation efficiency, particle size, and cloud altitude. We show that, depending on the observational filter, the largest possible shift of the phase curve maximum will be similar to 2 degrees-10 degrees for a Jupiter-like planet, and up to similar to 30 degrees (similar to 0.08 in fractional orbital phase) for hot-Jupiter exoplanets at visible wavelengths as a function of dayside cloud distribution with a uniformly averaged thermal profile. The models presented in this work can be adapted for a variety of planetary cases at visible wavelengths to include variations in planet-star separation, gravity, metallicity, and source-observer geometry. Finally, we tailor our model for comparison with, and confirmation of, the recent optical phase-curve observations of Kepler-7b with the Kepler space telescope. The average planetary albedo can vary between 0.1 and 0.6 for the 1300 cloud scenarios that were compared to the observations. Many of these cases cannot produce a high enough albedo to match the observations. We observe that smaller particle size and increasing cloud altitude have a strong effect on increasing albedo. In particular, we show that a set of models where Kepler-7b has roughly half of its dayside covered in small-particle clouds high in the atmosphere, made of bright minerals like MgSiO3 and Mg2SiO4, provide the best fits to the observed offset and magnitude of the phase-curve, whereas Fe clouds are found to be too dark to fit the observations

    An L Band Spectrum of the Coldest Brown Dwarf

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    The coldest brown dwarf, WISE 0855, is the closest known planetary-mass, free-floating object and has a temperature nearly as cold as the solar system gas giants. Like Jupiter, it is predicted to have an atmosphere rich in methane, water, and ammonia, with clouds of volatile ices. WISE 0855 is faint at near-infrared wavelengths and emits almost all its energy in the mid-infrared. Skemer et al. 2016 presented a spectrum of WISE 0855 from 4.5-5.1 micron (M band), revealing water vapor features. Here, we present a spectrum of WISE 0855 in L band, from 3.4-4.14 micron. We present a set of atmosphere models that include a range of compositions (metallicities and C/O ratios) and water ice clouds. Methane absorption is clearly present in the spectrum. The mid-infrared color can be better matched with a methane abundance that is depleted relative to solar abundance. We find that there is evidence for water ice clouds in the M band spectrum, and we find a lack of phosphine spectral features in both the L and M band spectra. We suggest that a deep continuum opacity source may be obscuring the near-infrared flux, possibly a deep phosphorous-bearing cloud, ammonium dihyrogen phosphate. Observations of WISE 0855 provide critical constraints for cold planetary atmospheres, bridging the temperature range between the long-studied solar system planets and accessible exoplanets. JWST will soon revolutionize our understanding of cold brown dwarfs with high-precision spectroscopy across the infrared, allowing us to study their compositions and cloud properties, and to infer their atmospheric dynamics and formation processes.Comment: 19 pages, 21 figures. Accepted for publication in Ap

    Observed Variability at 1um and 4um in the Y0 Brown Dwarf WISEP J173835.52+273258.9

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    We have monitored photometrically the Y0 brown dwarf WISEP J173835.52+273258.9 (W1738) at both near- and mid-infrared wavelengths. This ~1 Gyr-old 400K dwarf is at a distance of 8pc and has a mass around 5 M_Jupiter. We observed W1738 using two near-infrared filters at lambda~1um, Y and J, on Gemini observatory, and two mid-infrared filters at lambda~4um, [3.6] and [4.5], on the Spitzer observatory. Twenty-four hours were spent on the source by Spitzer on each of June 30 and October 30 2013 UT. Between these observations, around 5 hours were spent on the source by Gemini on each of July 17 and August 23 2013 UT. The mid-infrared light curves show significant evolution between the two observations separated by four months. We find that a double sinusoid can be fit to the [4.5] data, where one sinusoid has a period of 6.0 +/- 0.1 hours and the other a period of 3.0 +/- 0.1 hours. The near-infrared observations suggest variability with a ~3.0 hour period, although only at a <~2 sigma confidence level. We interpret our results as showing that the Y dwarf has a 6.0 +/- 0.1 hour rotation period, with one or more large-scale surface features being the source of variability. The peak-to-peak amplitude of the light curve at [4.5] is 3%. The amplitude of the near-infrared variability, if real, may be as high as 5 to 30%. Intriguingly, this size of variability and the wavelength dependence can be reproduced by atmospheric models that include patchy KCl and Na_2S clouds and associated small changes in surface temperature. The small number of large features, and the timescale for evolution of the features, is very similar to what is seen in the atmospheres of the solar system gas giants.Comment: Accepted by ApJ July 26 2016. Twenty-six pages include 8 Figures and 5 Table
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