15,949 research outputs found
Shock absorbing support and restraint means Patent
Shock absorbing couch for body support under high acceleration or deceleration force
Systematic Influences on Teaching Evaluations : The Case for Caution
The evaluation of teaching and learning has become an important activity in tertiary education institutions. Student surveys provide information about student perceptions and judgments of a particular subject. However, as is widely recognised, the appropriate interpretation of this data is problematic. There is a large literature, mainly for the US, on the use and usefulness of student subject evaluations. This literature has highlighted a number of āmitigating factorsā such as subject difficulty, discipline area, etc., that should be taken into account in interpreting the results of these questionnaires. In this paper we examine 8 years of QOT responses from an Economics Department in an Australian University which accounted for more than 79,000 student subject enrolments in 565 subjects. The purpose of this analysis is to establish how the information contained in these data can be used to interpret the responses. In particular, we determine to what extent other factors besides the instructor in charge of the subject have an impact on the raw average student evaluation scores. We find that the following characteristics of the students in these classes had an influence on the average QOT score: year level, enrolment size, the quantitative nature of the subject, the country of origin of the students, the proportion that are female, Honours status of the student, the differential in their mark from previous marks, quality of workbook, quality of textbook and the relative QOT score versus other subjects taught at the same time. However, a number of other factors proposed in the literature to be important influences were found not to be. These include the studentās fee paying status, whether they attended a public, private or catholic secondary school, which other faculty within the University they came from, and if the subject was taught in multiple sessions.
Identifying fabrication defects of metal packaged fibre Bragg grating sensors for smart pre-stressing strands
Metal packaged fibre Bragg grating sensors have the potential to provide reliable measurements of temperature and strain in high stress environments for the purpose of structural health monitoring. However due to the induction brazing fabrication process a small percentage of sensors are found to have defective brazed joints. We demonstrate a defect identification procedure derived from the batch temperature calibration of fibre Bragg grating sensors for temperature and strain measurement, allowing defective sensors to be identified before installation. The procedure was demonstrated on a sample of twelve temperature sensors fabricated for a small-scale smart pre-stressing strand validation test
HyperTraPS: Inferring probabilistic patterns of trait acquisition in evolutionary and disease progression pathways
The explosion of data throughout the biomedical sciences provides unprecedented opportunities to learn about the dynamics of evolution and disease progression, but harnessing these large and diverse datasets remains challenging. Here, we describe a highly generalisable statistical platform to infer the dynamic pathways by which many, potentially interacting, discrete traits are acquired or lost over time in biomedical systems. The platform uses HyperTraPS (hypercubic transition path sampling) to learn progression pathways from cross-sectional, longitudinal, or phylogenetically-linked data with unprecedented efficiency, readily distinguishing multiple competing pathways, and identifying the most parsimonious mechanisms underlying given observations. Its Bayesian structure quantifies uncertainty in pathway structure and allows interpretable predictions of behaviours, such as which symptom a patient will acquire next. We exploit the modelās topology to provide visualisation tools for intuitive assessment of multiple, variable pathways. We apply the method to ovarian cancer progression and the evolution of multidrug resistance in tuberculosis, demonstrating its power to reveal previously undetected dynamic pathways
Ultrasonic detection and identification of fabrication defects in composites
Methods for deliberate fabrication of porosity into carbon/epoxy composite panels and the influence of three-dimensional stitching on the detection of porosity were investigated. Two methods of introducing porosity were investigated. Porosity was simulated by inclusion of glass microspheres, and a more realistic form of porosity was introduced by using low pressure during consolidation. The panels were ultrasonically scanned and the frequency slope of the ultrasonic attenuation coefficient was used to evaluate the two forms of porosity. The influence of stitching on the detection of porosity was studied using panels which were resin transfer molded from stitched plies of knitted carbon fabric and epoxy resin
Influence of van der Waals forces on the adsorption structure of benzene on silicon studied using density functional theory
Two different adsorption configurations of benzene on the Si(001)-(2 x 1) surface, the tight-bridge and butterfly structures, were studied using density functional theory. Several exchange and correlation functionals were used, including the recently developed van der Waals density functional (vdW-DF), which accounts for the effect of van der Waals forces. In contrast to the Perdew-Burke-Ernzerhof (PBE), revPBE, and other generalized-gradient approximation functionals, the vdW-DF finds that, for most coverages, the adsorption energy of the butterfly structure is greater than that of the tight-bridge structure
Hex acts with beta-catenin to regulate anteroposterior patterning via a Groucho-related co-repressor and Nodal
Magnetic susceptibility study of hydrated and non-hydrated NaxCoO2-yH2O single crystals
We have measured the magnetic susceptibility of single crystal samples of
non-hydrated NaxCoO2 (x ~ 0.75, 0.67, 0.5, and 0.3) and hydrated Na0.3CoO2-yH2O
(y ~ 0, 0.6, 1.3). Our measurements reveal considerable anisotropy between the
susceptibilities with H||c and H||ab. The derived anisotropic g-factor ratio
(g_ab/g_c) decreases significantly as the composition is changed from the
Curie-Weiss metal with x = 0.75 to the paramagnetic metal with x = 0.3. Fully
hydrated Na0.3CoO2-1.3H2O samples have a larger susceptibility than
non-hydrated Na0.3CoO2 samples, as well as a higher degree of anisotropy. In
addition, the fully hydrated compound contains a small additional fraction of
anisotropic localized spins.Comment: 6 pages, 5 figure
Magnetic instability of a two-dimensional Anderson non-Fermi liquid
We show that in the Anderson model for a two-dimensional non-Fermi liquid a
magnetic instability can lead to the itinerant electron ferromagnetism. The
critical temperature and the susceptibility of the paramagnetic phase have been
analytically calculated. The usual Fermi behaviour is re-obtained taking the
anomalous exponent to be zero.Comment: 3 pages, Revte
ARPES studies of cuprate Fermiology: superconductivity, pseudogap, and quasiparticle dynamics
We present angle-resolved photoemission spectroscopy (ARPES) studies of the
cuprate high-temperature superconductors which elucidate the relation between
superconductivity and the pseudogap and highlight low-energy quasiparticle
dynamics in the superconducting state. Our experiments suggest that the
pseudogap and superconducting gap represent distinct states, which coexist
below T. Studies on Bi-2212 demonstrate that the near-nodal and
near-antinodal regions behave differently as a function of temperature and
doping, implying that different orders dominate in different momentum-space
regions. However, the ubiquity of sharp quasiparticles all around the Fermi
surface in Bi-2212 indicates that superconductivity extends into the
momentum-space region dominated by the pseudogap, revealing subtlety in this
dichotomy. In Bi-2201, the temperature dependence of antinodal spectra reveals
particle-hole asymmetry and anomalous spectral broadening, which may constrain
the explanation for the pseudogap. Recognizing that electron-boson coupling is
an important aspect of cuprate physics, we close with a discussion of the
multiple 'kinks' in the nodal dispersion. Understanding these may be important
to establishing which excitations are important to superconductivity.Comment: To appear in a focus issue on 'Fermiology of Cuprates' in New Journal
of Physic
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