20,402 research outputs found
A comprehensive WebCT integration system
Murdoch University, in collaboration with industry partners, has developed a sophisticated middleware application (WebCTMan) between WebCT and other corporate systems, such as the Callista student records system, the Concept 1 human resources system and Murdoch’s own authentication system. This presentation will describe the architecture and functionality of this system.
The impetus for WebCTMan was to enable Murdoch to change its student records database with minimal impact on our WebCT installation. However, WebCTMan now gives us great flexibility in managing our WebCT installation, enabling us to manage courses across teaching periods, and upgrade easily. This paper describes the context in which this system was built and gives an overview of its architecture.
Courses in WebCTMan can have a status of active (where student details are updated nightly), inactive (where all students are orphans), and static (where student accounts are valid but not updated). Tools are available to change this status, and easily activate and deactivate courses. Different versions of courses are maintained for each teaching period, resolving the problem of overlap between semesters, when some students still have deferred examinations after the start of a new semester.
In addition to managing students, WebCTMan provides functionality to manage staff and courses. Staff can request courses to be created or cloned from other courses. They can also create their own guest accounts and allocate tutors and markers to courses, and download class lists. Operators can create or rename courses on demand, as well as changing the roles of staff, including primary and secondary designers. A subset of functions is available to helpdesk operators, who can lookup details of both students and staff within the system
Dislocation plasticity in thin metal films
This article describes the current level of understanding of dislocation plasticity in thin
films and small structures in which the film or structure dimension plays an important
role. Experimental observations of the deformation behavior of thin films, including
mechanical testing as well as electron microscopy studies, will be discussed in light of
theoretical models and dislocation simulations. In particular, the potential of applying
strain-gradient plasticity theory to thin-film deformation is discussed. Although the
results of all studies presented follow a “smaller is stronger” trend, a clear functional
dependence has not yet been established
Mottness: Identifying the Propagating Charge Modes in doped Mott Insulators
High-temperature superconductivity in the copper-oxide ceramics remains an
unsolved problem because we do not know what the propagating degrees of freedom
are in the normal state. As a result, we do not know what are the weakly
interacting degrees of freedom which pair up to form the superconducting
condensate. That the electrons are not the propagating degrees of freedom in
the cuprates is seen most directly from experiments that show spectral weight
redistributions over all energy scales. Of course, the actual propagating
degrees of freedom minimize such spectral rearrangements. This review focuses
on the range of epxerimental consequences such UV-IR mixings have on the normal
state of the cuprates, such as the pseudogap, mid-infrared band, temperature
dependence of the Hall number, the superfluid density, and a recent theoretical
advance which permits the identification of the weakly interacting degrees of
freedom in a doped Mott insulator. Within this theory, we show how the wide
range of phenomena which typify the normal state of the cuprates arises
including linear resistivity.Comment: To appear as a Colloquium in the April issue of Rev. Mod. Phys
Updated version contains new references and a clarification concerning Fig.
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A mathematical framework for nerve regeneration in implantable conduits
Matching the performance of autografts with engineered scaffolds remains a challenge in peripheral nerve repair. A combination of 3D biomimetic architecture interspersed with 2D surfaces has been hypothesized to be an ideal environment for neurite regeneration. However, the problem of how best to arrange material within a conduit is an open one. Optimizing material parameters such as density, cross-sectional geometry and spatial distribution would require an extensive programme of experimental testing. By contrast, developing a modelling framework that is capable of testing key parameters may accelerate the design process, and reduce the dependency on animal testing
Evidence for Ubiquitous Collimated Galactic-Scale Outflows along the Star-Forming Sequence at z~0.5
We present an analysis of the MgII 2796, 2803 and FeII 2586, 2600 absorption
line profiles in individual spectra of 105 galaxies at 0.3<z<1.4. The galaxies,
drawn from redshift surveys of the GOODS fields and the Extended Groth Strip,
fully sample the range in star formation rates (SFRs) occupied by the
star-forming sequence with stellar masses log M_*/M_sun > 9.5 at 0.3<z<0.7.
Using the Doppler shifts of the MgII and FeII absorption lines as tracers of
cool gas kinematics, we detect large-scale winds in 66+/-5% of the galaxies.
HST/ACS imaging and our spectral analysis indicate that the outflow detection
rate depends primarily on galaxy orientation: winds are detected in ~89% of
galaxies having inclinations (i) <30 degrees (face-on), while the wind
detection rate is only ~45% in objects having i>50 degrees (edge-on). Combined
with the comparatively weak dependence of the wind detection rate on intrinsic
galaxy properties, this suggests that biconical outflows are ubiquitous in
normal, star-forming galaxies at z~0.5. We find that the wind velocity is
correlated with host galaxy M_* at 3.4-sigma significance, while the equivalent
width of the flow is correlated with host galaxy SFR at 3.5-sigma significance,
suggesting that hosts with higher SFR may launch more material into outflows
and/or generate a larger velocity spread for the absorbing clouds. Assuming
that the gas is launched into dark matter halos with simple, isothermal density
profiles, the wind velocities measured for the bulk of the cool material
(~200-400 km/s) are sufficient to enable escape from the halo potentials only
for the lowest-M_* systems in the sample. However, the outflows typically carry
sufficient energy to reach distances of >50 kpc, and may therefore be a viable
source of cool material for the massive circumgalactic medium observed around
bright galaxies at z~0. [abridged]Comment: Submitted to ApJ. 61 pages, 25 figures, 4 tables, 4 appendices. Uses
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X-ray photoelectron spectroscopy measurement of valence-band offsets for Mg-based semiconductor compounds
We have used x-ray photoelectron spectroscopy to measure the valence-band offsets for the lattice matched MgSe/Cd0.54Zn0.46Se and MgTe/Cd0.88Zn0.12Te heterojunctions grown by molecular beam epitaxy. By measuring core level to valence-band maxima and core level to core level binding energy separations, we obtain values of 0.56+/-0.07 eV and 0.43+/-0.11 eV for the valence-band offsets of MgSe/Cd0.54Zn0.46Se and MgTe/Cd0.88Zn0.12Te, respectively. Both of these values deviate from the common anion rule, as may be expected given the unoccupied cation d orbitals in Mg. Application of our results to the design of current II-VI wide band-gap light emitters is discussed
Improving analysis practice of continuous adverse event outcomes in randomised controlled trials – a distributional approach
Background Randomised controlled trials (RCTs) provide valuable information for developing harm profiles but current analysis practices to detect between-group differences are suboptimal. Drug trials routinely screen continuous clinical and biological data to monitor participant harm. These outcomes are regularly dichotomised into abnormal/normal values for analysis. Despite the simplicity gained for clinical interpretation, it is well established that dichotomising outcomes results in a considerable reduction in information and thus statistical power. We propose an automated procedure for the routine implementation of the distributional method for the dichotomisation of continuous outcomes proposed by Peacock and Sauzet, which retains the precision of the comparison of means. Methods We explored the use of a distributional approach to compare differences in proportions based on the comparison of means which retains the power of the latter. We applied this approach to the screening of clinical and biological data as a means to detect ‘signals’ for potential adverse drug reactions (ADRs). Signals can then be followed-up in further confirmatory studies. Three distributional methods suitable for different types of distributions are described. We propose the use of an automated approach using the observed data to select the most appropriate distribution as an analysis strategy in a RCT setting for multiple continuous outcomes. We illustrate this approach using data from three RCTs assessing the efficacy of mepolizumab in asthma or COPD. Published reference ranges were used to define the proportions of participants with abnormal values for a subset of 10 blood tests. The between-group distributional and empirical differences in proportions were estimated for each blood test and compared. Results Within trials, the distributions varied across the 10 outcomes demonstrating value in a practical approach to selecting the distributional method in the context of multiple adverse event outcomes. Across trials, there were three outcomes where the method chosen by the automated procedure varied for the same outcome. The distributional approach identified three signals (eosinophils, haematocrit, and haemoglobin) compared to only one when using the Fisher’s exact test (eosinophils) and two identified by use of the 95% confidence interval for the difference in proportions (eosinophils and potassium). Conclusion When dichotomisation of continuous adverse event outcomes aids clinical interpretation, we advocate use of a distributional approach to retain statistical power. Methods are now easy to implement. Retaining information is especially valuable in the context of the analysis of adverse events in RCTs. The routine implementation of this automated approach requires further evaluation
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