A Delphi study on collaborative learning in distance education

Collaborative Learning (CL) is increasingly being used in Distance Education (DE), as it has been identified as an effective solution to known weaknesses such as high average rates of dropout and low quality of learning attainment. Information Technology is a core component of this type of learning as it not only provides the means to collaborate over distance but also has the potential to enable higher learning outcomes. There are a rapidly growing number of technologies in use today and the importance of these to collaborative learning initiatives, and the role they play, is an area of active research in the Information Systems (IS) community. IS educators and practitioners face an increasing challenge therefore to successfully implement CL in DE, precipitated not only from technical advances but also from wider social and organisational concerns. Using a Delphi study, this research is the first to investigate the factors that influence collaborative learning in distance education by surveying the opinions of an expert panel in this area. The aim was to produce an integrated list of the most important implementation factors and to investigate the role technology is perceived to contribute. The findings identified seventeen of the most important factors. These factors cover a range of themes including course rationale and design, instructor characteristics, training, group dynamics, the development of a learning community and technology. The potential of technology however does not seem to be fully realised and newer technologies such as multi-user environments would seem to be of limited use in practice, according to the expert panel

Carbon catalysed hydrogen exchange in petroleum source rocks

Exchange of carbon bound hydrogen has been observed when alkenes, saturated and aromatic hydrocarbons are heated at moderate temperatures on carbonaceous surfaces (activated carbon and coal). Isomerisation of alkenes and the formation of hydrogenated/dehydrogenated products from the saturated and aromatic reactants resulted. A suite of crude oils from the Carnarvon Basin (Western Australia) have been analysed with a view to comparing their relative abundances of structurally similar hydrocarbons. The consistent relationships between hydrocarbons in crude oils that are chemically related via hydrogenation/dehydrogenation reactions suggest that a hydrogen exchange process similar to that demonstrated in laboratory experiments occurs during crude oil formation in sedimentary rocks

Towards a Toolset for Intranet Evaluation

Usability is an important component of information systems acceptance. Independent consultants in the assessment of organisational intranets often perform heuristic appraisal, a common method of usability evaluation. However, there are alternative usability models that offer valuable analysis in the evaluation process. Using a government organisation’s intranet as a case study, this paper assesses the value of an independent heuristic-based intranet audit by providing a comparable approach to assessment realisable internally in the organisation using questionnaires. Using a single case study, we empirically apply the Technology Acceptance Model (TAM), together with some heuristic aspects, to provide an alternative tool for intranet usability and acceptance. We provide insight into the usability impact of intranet design changes, and compare the findings of an external usability audit with the approach outlined. An overall toolset for intranet evaluation is proposed as an initial step for further exploration and potential use

Mechanical loss of a multilayer tantala/silica coating on a sapphire disk at cryogenic temperatures: toward the KAGRA gravitational wave detector

We report the results of a new experimental setup to measure the mechanical loss of coating layers on a thin sapphire disk at cryogenic temperatures. Some of the authors previously reported that there was no temperature dependence of the mechanical loss from a multilayer tantala/silica coating on a sapphire disk, both before and after heat treatment, although some reports indicate that Ta<sub>2</sub>O<sub>5</sub> and SiO<sub>2</sub> layers annealed at 600 °C have loss peaks near 20 K. Since KAGRA—the Japanese gravitational-wave detector, currently under construction—will be operated at 20 K and have coated sapphire mirrors, it is very important to clarify the mechanical loss behavior of tantala/silica coatings around this temperature. We carefully investigate a tantala/silica-coated sapphire disk with the new setup, anneal the disk, and then investigate the annealed disk. We find that there is no distinct loss peak both before and after annealing under particular conditions. The mechanical loss for the unannealed disk at 20 K is about 5×10<sup>−4</sup>, as previously reported, while that for the annealed disk is approximately 6.4×10<sup>−4</sup>

Dietary long-chain, but not medium-chain, triglycerides impair exercise performance and uncouple cardiac mitochondria in rats.

Short-term consumption of a high-fat diet impairs exercise capacity in both rats and humans, and increases expression of the mitochondrial uncoupling protein, UCP3, in rodent cardiac and skeletal muscle via activation of the transcription factor, peroxisome proliferator-activated receptor α (PPARα). Unlike long-chain fatty acids however, medium-chain fatty acids do not activate PPARα and do not increase muscle UCP3 expression. We therefore investigated exercise performance and cardiac mitochondrial function in rats fed a chow diet (7.5% kcal from fat), a long-chain triglyceride (LCT) rich diet (46% kcal from LCTs) or a medium-chain triglyceride (MCT) rich diet (46% kcal from MCTs). Rats fed the LCT-rich diet for 15 days ran 55% less far than they did at baseline, whereas rats fed the chow or MCT-rich diets neither improved nor worsened in their exercise capacities. Moreover, consumption of an LCT-rich diet increased cardiac UCP3 expression by 35% and decreased oxidative phosphorylation efficiency, whereas consumption of the MCT-rich diet altered neither UCP3 expression nor oxidative phosphorylation efficiency. Our results suggest that the negative effects of short-term high-fat feeding on exercise performance are predominantly mediated by long-chain rather than medium-chain fatty acids, possibly via PPARα-dependent upregulation of UCP3.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Cryogenic mechanical loss of a single-crystalline GaP coating layer for precision measurement applications

The first direct observations of gravitational waves have been made by the Advanced LIGO detectors. However, the quest to improve the sensitivities of these detectors remains, and epitaxially grown single-crystal coatings show considerable promise as alternatives to the ion-beam sputtered amorphous mirror coatings typically used in these detectors and other such precision optical measurements. The mechanical loss of a 1 μm thick single-crystalline gallium phosphide (GaP) coating, incorporating a buffer layer region necessary for the growth of high quality epitaxial coatings, has been investigated over a broad range of frequencies and with fine temperature resolution. It is shown that at 20 K the mechanical loss of GaP is a factor of 40 less than an undoped tantala film heat-treated to 600 °C and is comparable to the loss of a multilayer GaP/AlGaP coating. This is shown to translate into possible reductions in coating thermal noise of a factor of 2 at 120 K and 5 at 20 K over the current best IBS coatings (alternating stacks of silica and titania-doped tantala). There is also evidence of a thermally activated dissipation process between 50 and 70 K

A General Business Model for Marine Reserves

Marine reserves are an effective tool for protecting biodiversity locally, with potential economic benefits including enhancement of local fisheries, increased tourism, and maintenance of ecosystem services. However, fishing communities often fear short-term income losses associated with closures, and thus may oppose marine reserves. Here we review empirical data and develop bioeconomic models to show that the value of marine reserves (enhanced adjacent fishing + tourism) may often exceed the pre-reserve value, and that economic benefits can offset the costs in as little as five years. These results suggest the need for a new business model for creating and managing reserves, which could pay for themselves and turn a profit for stakeholder groups. Our model could be expanded to include ecosystem services and other benefits, and it provides a general framework to estimate costs and benefits of reserves and to develop such business models

Ion-beam sputtered amorphous silicon films for cryogenic precision measurement systems

Thermal noise resulting from the mechanical loss of multilayer dielectric coatings is expected to impose a limit to the sensitivities of precision measurement systems used in fundamental and applied science. In the case of gravitational wave astronomy, future interferometric gravitational wave detectors are likely to operate at cryogenic temperatures to reduce such thermal noise and ameliorate thermal loading effects, with the desirable thermomechanical properties of silicon making it an attractive mirror substrate choice for this purpose. For use in such a precision instrument, appropriate coatings of low thermal noise are essential. Amorphous silicon (a−Si) deposited by e-beam and other techniques has been shown to have low mechanical loss. However, to date, the levels of mechanical and optical loss for a−Si when deposited by ion-beam sputtering (the technique required to produce amorphous mirrors of the specification for gravitational wave detector mirrors) are unknown. In this paper results from measurements of the mechanical loss of a series of IBS a−Si films are presented which show that reductions are possible in coating thermal noise of a factor of 1.5 at 120 K and 2.1 at 20 K over the current best IBS coatings (alternating stacks of silica and titania-doped tantala), with further reductions feasible under appropriate heat treatments

Predation on Multiple Prey Types Across a Disturbance Gradient in Tropical Montane Forests of Peninsular Malaysia

Predation plays a critical role in animal and plant survivorship, and can be highly sensitive to habitat loss and disturbance. Tropical montane forests in Southeast Asia are being modified rapidly by land-use change, and the consequences of this on predation likelihood are poorly understood. In Peninsular Malaysia, we conducted predation experiments at eight tropical montane forest sites along a disturbance gradient. We investigated whether (1) predation pressure in primary forests differs between different mountains; (2) predation probability is linked to habitat degradation; and (3) vegetation variables explain predation occurrence. At each forest site, we placed artificial nests with real and model quail eggs, dishes with real and artificial seeds of the cempedak (Artocarpus champeden), models resembling four-lined tree frogs (Polypedetes leucomystax) and models of the late instar caterpillar of the common Mormon (Papilio polytes) at points 100 m apart for three nights. Using Bayesian binomial simulations, we showed that predation likelihood in primary forests from different mountains can vary (e.g., probability of the difference in predation rate of artificial caterpillars between two primary forests was estimated at 82–100%). We also found that higher predation was not linked to habitat degradation for all artificial prey and seeds (e.g., comparing forests of varying degrees of disturbance from the same mountain, the probability that predation of an artificial caterpillar is lower at the primary forest was estimated at 2–20% only). Model selection and hierarchical partitioning showed that vegetation variables can explain predation occurrence, suggesting microhabitat characteristics may be influential. Conducting predation experiments by using artificial prey and seeds is useful for comparing predation likelihood at different sites, making ecological comparisons, and for informing conservation decisions. This novel approach of using multiple prey items also showed that predation for each can vary and thus caution against deploying a single prey type to draw broad inferences of predation in degraded systems