4,067 research outputs found
Assessment worlds colliding? Negotiating between discourses of assessment on an online open course
Using the badged open course, Taking your first steps into Higher Education, this case study examines how assessment on online open courses draws on concepts of assessment used within formal and informal learning. Our experience was that assessment used within open courses, such as massive open online courses, is primarily determined by the requirements of quality assurance processes to award a digital badge or statement of participation as well as what is technologically possible. However, this disregards much recent work in universities that use assessment in support of learning. We suggest that designers of online open courses should pay greater attention to the relationship of assessment and learning to improve participant course completion
Think Different: Applying the Old Macintosh Mantra to the Computability of the SUSY Auxiliary Field Problem
Starting with valise supermultiplets obtained from 0-branes plus field
redefinitions, valise adinkra networks, and the "Garden Algebra," we discuss an
architecture for algorithms that (starting from on-shell theories and, through
a well-defined computation procedure), search for off-shell completions. We
show in one dimension how to directly attack the notorious "off-shell auxiliary
field" problem of supersymmetry with algorithms in the adinkra network-world
formulation.Comment: 28 pages, 1 figur
Factors influencing clinical outcome in vestibular neuritis – A focussed review and reanalysis of prospective data
Following vestibular neuritis (VN), long term prognosis is not dependent on the magnitude of the residual peripheral function as measured with either caloric or the video head-impulse test. Rather, recovery is determined by a combination of visuo-vestibular (visual dependence), psychological (anxiety) and vestibular perceptual factors. Our recent research in healthy individuals has also revealed a strong association between the degree of lateralisation of vestibulo-cortical processing and gating of vestibular signals, anxiety and visual dependence. In the context of several functional brain changes occurring in the interaction between visual, vestibular and emotional cortices, which underpin the aforementioned psycho-physiological features in patients with VN, we re-examined our previous published findings focusing on additional factors impacting long term clinical outcome and function. These included: (i) the role of concomitant neuro-otological dysfunction (i.e. migraine and benign paroxysmal positional vertigo (BPPV)) and (ii) the degree to which brain lateralisation of vestibulo-cortical processing influences gating of vestibular function in the acute stage. We found that migraine and BPPV interfere with symptomatic recovery following VN. That is, dizziness handicap at short-term recovery stage was significantly predicted by migraine (r=0.523, n=28, p=.002), BPPV (r=0.658, n=31, p0.05). In left-sided VN patients, we observed a negative correlation between visual dependence and ipsilesional oculomotor thresholds (R2 0.459; p0.05). To summarise, our findings illustrate that in VN, neuro-otological co- morbidities retard recovery, and that measures of the peripheral vestibular system are an aggregate of residual function and cortically mediated gating of vestibular input
Impairment of spatial cognitive function with preservation of verbal performance during spatial disorientation
Spatial disorientation, which is responsible for up to 30% of aircraft accidents causes impairment of cognitive function which may further compromise a pilot's ability to think his way out of the situation and regain control [1,]. The functional-anatomical separation of spatial and verbal processing [10,11] raises the possibility of selective interference between the task of resolving spatial disorientation and the ability to perform concurrent spatial, as opposed to verbal, secondary tasks. We report for the first time a degradation of spatial task performance with preservation of verbal performance when subjects in a simulator are disoriented by conflict between self- motion and visual flow in the view of the external environment
Prevalence, Predictors & Prevention of Motion Sickness in Zero-G Parabolic Flights
INTRODUCTION
Zero-G parabolic flight reproduces the weightlessness of space for short periods of time. However motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors.
METHODS
Airbus Zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20s 0g sandwiched by 20s hypergravity of 1.5-1.8g. The survey covered n=246 person-flights (193 Males 53 Females), aged (M+/-SD) 36.0+/-11.3 years. An anonymous questionnaire included motion sickness rating (1=OK to 6=Vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), anti-motion sickness medication, prior Zero-G experience, anxiety level, and other characteristics.
RESULTS
Participants had lower MSSQ percentile scores 27.4+/-28.0 than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior Zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender nor anxiety. Sickness ratings in fliers pre-treated with scopolamine (1.81+/-1.58) were lower than for non-medicated fliers (2.93+/-2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, MSSQ, could not account for this.
CONCLUSION
Motion sickness affected one third of Zero-G fliers, despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior Zero-G flight experience (habituation) and anti-motion sickness medication
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Selective cancer cell toxicity and radiosensitization using different high atomic number nanoparticles
Radiotherapy is currently used in around 50% of cancer treatments. Although it is generally effective, it is damaging to surrounding healthy tissues. This damage can be reduced by by better targeting to cancer cells. Improved radiotherapy outcomes can be achieved by targeting heavy elements to cancer cells, since these produce energetic electrons and free radicals upon irradiation that further increase the effectiveness of radiotherapy. Because of their biocompatibility and amenability to surface modification, gold nanoparticles (AuNPs) show significant promise in this area.We observe that acute 3hr exposure of cells to 2nm gold nanoparticles, bearing a 50:50 ratio of alpha-galactose and PEGamine ligands, results in selective chemotoxicity toward cancer cells at nanomolar concentrations, without affecting normal cells (Figure 1). Chemotoxicity is prevented by antioxidant co-administration and is partially prevented by a pan-caspase inhibitor (ZVAD- fmk). Our initial results suggest that AuNP toxicity is additive with using X-ray radiotherapy. Cerium oxide NPs are one of the most studied metal oxides NPs due to their high redox and oxygen transport properties [1]. They are interesting for radiotherapy applications because they adsorb oxygen and may therefore favour the radiolytic production of oxygen-containing free radicals, especially under low-oxygen conditions, such as the environment of most solid tumours. The surface oxygen vacancy of ceria NPs therefore makes them an interesting tool for prooxidant properties [2,3]. Nevertheless, the potential of ceria as a radiosensitiser has not been investigated extensively as it has a relatively low atomic number. It will therefore produce a low flux of secondary electrons upon irradiation which could potentially displace the adsorbed oxygen. We have been working on the fabrication of mixed ceria NPs, incorporating gold or bismuth, to increase the flux of secondary electrons (Figure 2). It is hoped these effects combined will further facilate the localized generation of ROS and increase effectiveness of targetted radiotherapy We predict that these new mixed-oxide ceria NPs will have better radiosensitisation potential than pure ceria NPs, and could be used to effectively target hypoxic cancer cells
Horizontal stress anisotropy and effective stress as regulator of coal seam gas zonation in the Sydney Basin, Australia
Coal seam gas zonation in the Sydney Basin, NSW, Australia is related to basin hydrodynamics and hydrochemical facies evolution along the flow path from the subcrop to the basin center. Biogenic methane corresponds with meteoric water under hydrostatic pressure and persists down to the top of the geopressured zone (~800 to 1000m). Thermogenic gases, including wet hydrocarbons, can reach up to relatively shallow horizons of less than 500-600m depth. In the transition zone between the top of the geopressured and base of the hydrostatic zone, a mixed water and gas regime prevails, comprising brackish waters, and gases of mixed biogenic, thermogenic and inorganic origins, including CO. Mechanisms for and the role of stress in the development of this layered hydrogeological and gas environment are investigated in this paper.The inverse relationship between effective horizontal stress and permeability in coals through regulation of cleat volumes is well documented, and there is evidence of regionally compartmentalized stress regimes with depth within the Sydney and other eastern Australian coal basins. This regional stress regime can be overprinted by the effect of localized geological features. It is hypothesized that the in situ stress regime plays an important role in the regulation of groundwater flow regimes and extents, resulting in the development of the reported gas content and compositional zonation.Analysis of regional gas and stress data obtained from public and private databases, as well as literature, supports this hypothesis. Changes in gas concentration and composition with depth correspond with discernable variations in horizontal stress anisotropy. Gas contents generally increase with depth down to a 'peak gas' horizon, below which concentrations decrease. This 'peak gas' zone is coincident with a horizontal stress anisotropy change from moderately high to low levels, associated with reverse to strike-slip faulting conditions, respectively. The stress release zone also marks the top of the thermogenic gas zone, identified by the first appearance of ethane in the vertical profile. This zone also hosts gases of mixed origins: biogenic, thermogenic and inorganic (CO) and represents a mixed (transitional) groundwater flow environment. The base of the mixed gas zone is the top of the 'geopressured-only' flow associated with thermogenic gases and is signaled by the return to high stress reverse faulting conditions below 850-900m depth in the Sydney Basin
Lambda-prophage induction modeled as a cooperative failure mode of lytic repression
We analyze a system-level model for lytic repression of lambda-phage in E.
coli using reliability theory, showing that the repressor circuit comprises 4
redundant components whose failure mode is prophage induction. Our model
reflects the specific biochemical mechanisms involved in regulation, including
long-range cooperative binding, and its detailed predictions for prophage
induction in E. coli under ultra-violet radiation are in good agreement with
experimental data.Comment: added referenc
Development and application of rice starch based edible coating to improve the postharvest storage potential and quality of plum fruit (<i>Prunus salicina</i>)
The study investigated the possibility of enhancing the shelf life of plum fruit coated with rice starch-ι-carrageenan (RS-ι-car) composite coating blended with sucrose fatty acid esters (FAEs). Film solution (starch 3%, carrageenan 1.5% and FAEs 2%) was prepared by mixing the ingredients and properties of stand-alone films (physical, mechanical, barrier and surface morphology) were studied before applying the coating on fruit surface. Fruit were stored at 20 °C for 3 weeks and analyzed for weight loss, ethylene production, respiration rate, color change, firmness, and titratable acidity (TA) and soluble solid content (SSC). Surface morphology of stand-alone film and fruit surface (after applying on the plum fruit) was studied using scanning electron microscopy (SEM). Phytochemical analysis was performed during the storage period and total phenolic content (TPC), total antioxidant capacity (TAC), flavonoid content (FC) and free radical scavenging activity were determined. The rice starch composite coating was shown to be effective in reducing both weight loss (WL) and respiration rate and inhibiting the endogenous ethylene production when compared to the uncoated control fruit stored at room temperature (p < 0.05). TPC, TAC, FC and free radical scavenging activity was unaffected in the coated fruit throughout the storage period (p < 0.05). The findings reported in this study indicate that the RS-ι-car-FAEs coating prolongs the shelf life and maintains the overall quality of plum fruit during storage and could potentially be commercialized as a new edible coating for the plum fruit industry
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