762 research outputs found

    Evaluating quality in online asynchronous interactions between students and discussion facilitators

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    Online discussion forums have become an essential part of university courses, whether the course is conducted online, or face to face, or in mixed or blended mode. Discussion forums are considered to engage students better with the course content and encourage them to share and gain knowledge from each other. However, online engagement does not always happen automatically between students. Hence grading of discussion forum participation has been recommended to ensure quality student participation. Currently, a major focus has been put onto the better use of discussion forums, but the way in which the quality of participation can be evaluated has yet to be adequately investigated. Furthermore, evaluation of the instructor participation in a discussion forum and its impact on students and their contributions is lacking. In this paper, we report on our research into online discussion forum quality through analysis of discussion forum activities, along with student focus group meetings and instructor interviews. We have devised a set of criteria for evaluating discussion forum activities. Our results show that students depend highly on the instructor's feedback and the participation of the students can only be evaluated with reference to the moderation of the instructors

    Virtual anthropology: a preliminary test of macroscopic observation versus 3D surface scans and computed tomography (CT) scans.

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    Virtual anthropology (VA) is based on applying anthropological methods currently used to analyse bones to 3D models of human remains. While great advances have been made in this endeavour in the past decade, several interrogations concerning how reliable these models are and what their proper use should be remain unanswered. In this research, a fundamental assumption of VA has been investigated: if the way we perceive and apply an anthropological method is truly similar when looking at bones macroscopically and through various 3D media. In order to answer, 10 skulls of known age and sex were scanned using a computed tomography (CT) scanner and a 3D surface scanner. Two observers separately applied a defined staging method to eight suture sites on these skulls, first looking at the bone macroscopically, then at the 3D surface scan, and finally on the CT scan. Two rounds of observation were carried out by each observer. Intra- and inter-observer error were evaluated, and two sample t-tests used to evaluate if the different types of medium used yielded significantly different observations. The results show a high degree of inter-observer error, and that data obtained from 3D surface scans differ from macroscopic observation (confidence level 95%, P ≤ 0.05). CT scans, in these settings, yielded results comparable to those obtained through macroscopic observations. These results offer many possibilities for future research, including indications on the kind of anthropological methods and anatomical landmarks that might be reliably transferable to the virtual environment. All current methods used in traditional anthropology should be tested, and if they prove unreliable, new techniques to analyse bones from virtual models should be developed.Key pointsLarge discrepancies between observation on dry bones and computer-generated 3D models (surface scans or CT scans) could lead to the re-evaluation of the suitability of traditional anthropological methods for application on 3D models.This preliminary study evaluates whether macroscopic, 3D surface scans, and CT scans viewings generate different observations.The results indicate that the data are not always coherent across all three media of observation.Explanations include the aspect given to the bone by the 3D software, differences between handling bones in real life versus on a computer, and level of expertise of the observers

    Optical properties of bulk high-entropy diborides for solar energy applications

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    So far, the studies regarding the innovative High-Entropy Borides (HEBs), which belong to the more general class of Ultra-high temperature ceramics (UHTCs), have been entirely confined to their fabrication or characterization from the microstructural, mechanical and oxidation resistance viewpoints. In this work, the optical properties of two members of HEBs, i.e. (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 and (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, are evaluated for the first time to assess their possible utilization in the thermal solar energy field. The bulk samples (96.5 % and 97.4 % dense, respectively) are obtained as single-phase products by Spark Plasma Sintering (1950 °C/20 min/20 MPa) starting from powders previously synthesized by Self-propagating High-temperature Synthesis (SHS). The optical characterization, whose results are discussed by comparing HEBs to the individual borides, shows that they are characterized by intrinsic spectral selectivity and low thermal emittance, resulting therefore interesting for high-temperature solar absorbers applications

    Resilience of small-scale societies: a view from drylands.

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    To gain insights on long-term social-ecological resilience, we examined adaptive responses of small-scale societies to dryland-related hazards in different regions and chronological periods, spanning from the mid-Holocene to the present. Based on evidence from Africa (Sahara and Sahel), Asia (south margin of the Thar desert), and Europe (South Spain), we discuss key traits and coping practices of small-scale societies that are potentially relevant for building resilience. The selected case studies illustrate four main coping mechanisms: mobility and migration, storage, commoning, and collective action driven by religious beliefs. Ultimately, the study of resilience in the context of drylands emphasizes the importance of adaptive traits and practices that are distinctive of small-scale societies: a strong social-ecological coupling, a solid body of traditional ecological knowledge, and a high degree of internal cohesion and self-organization.SP2016http://www.ecologyandsociety.org/vol21/iss2/art53

    Multi-proxy survey of open-air surface scatters in drylands: Archaeological and physico-chemical characterisation of fossilised dunes in North Gujarat (India)

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    This research aims at improving our understanding of open-air archaeological surface scatters in drylands, their extension and the intensity of human activities during their occupation. To do so, the study of physico-chemical proxies is integrated to that of archaeological artefacts by means of systematic field survey combined with laboratory sedimentary analyses and a robust statistical approach. In most dry regions, archaeological survey has traditionally aimed at the collection of artefacts. When present, the study of physical and geochemical samples has been limited to excavated archaeological levels. In this work, we evaluate the archaeological significance of physico-chemical proxies from surface samples collected within and around four mid and late-Holocene surface scatters in North Gujarat, a semi-arid region located at the south-west margin of the Thar Desert in India. The four archaeological scatters are found on top of fossilised sand dunes. Archaeologically, they represent subsistence strategies based on hunting and gathering, agro-pastoralism, or a succession/mixture of the two. The four locations were systematically sampled across a linear transect. For each sampling unit, the archaeological materials were quantified and classified by means of a Linear Discriminant Analyses. Physio-chemical variables were ordinated in a PCA space and clustered through a Hierarchical Clustering. Results were displayed along the dune transect and integrated into a Correspondence Analysis. Significant differences are attested in the spatial distribution and content of Ca, P and grain size, allowing us to suggest a set of distinct cultural soilscapes that characterise the dunes of the study area: vertisols (agric horizons in interdunal lower slopes), aridisols (relict dune surfaces in the mid-slope), and anthrosols (top dune). The last show a strong correspondence with the presence of archaeological artefacts, and the different intensity of human footprint are discussed accordingly to potential past subsistence strategies and the intensity of human occupation. © 2016 Elsevier Ltd and INQUA.This research arises from collaboration between the MS University of Baroda and the IMF-CSIC (Spanish National Research Council) within the framework of the North Gujarat Archaeological Project (NoGAP) and the SimulPast Project CSD2010-00034). F.C.Conesa acknowledges worked on this paper with funding from the JAE-PreDoc program (CSIC and European Social Found). A. L. Balbo worked on this paper under the Juan de la Cierva Programme (MINECO JCI-2011-10734), and with a Research Fellowship from the Alexander von Humboldt Foundation/Stiftung.Peer reviewe

    A computational approach based on the colored Petri net formalism for studying multiple sclerosis

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    Multiple Sclerosis (MS) is an immune-mediated inflammatory disease of the Central Nervous System (CNS) which damages the myelin sheath enveloping nerve cells thus causing severe physical disability in patients. Relapsing Remitting Multiple Sclerosis (RRMS) is one of the most common form of MS in adults and is characterized by a series of neurologic symptoms, followed by periods of remission. Recently, many treatments were proposed and studied to contrast the RRMS progression. Among these drugs, daclizumab (commercial name Zinbryta), an antibody tailored against the Interleukin-2 receptor of T cells, exhibited promising results, but its efficacy was accompanied by an increased frequency of serious adverse events. Manifested side effects consisted of infections, encephalitis, and liver damages. Therefore daclizumab has been withdrawn from the market worldwide. Another interesting case of RRMS regards its progression in pregnant women where a smaller incidence of relapses until the delivery has been observed

    Data compression for the First G-APD Cherenkov Telescope

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    The First Geiger-mode Avalanche photodiode (G-APD) Cherenkov Telescope (FACT) has been operating on the Canary island of La Palma since October 2011. Operations were automated so that the system can be operated remotely. Manual interaction is required only when the observation schedule is modified due to weather conditions or in case of unexpected events such as a mechanical failure. Automatic operations enabled high data taking efficiency, which resulted in up to two terabytes of FITS files being recorded nightly and transferred from La Palma to the FACT archive at ISDC in Switzerland. Since long term storage of hundreds of terabytes of observations data is costly, data compression is mandatory. This paper discusses the design choices that were made to increase the compression ratio and speed of writing of the data with respect to existing compression algorithms. Following a more detailed motivation, the FACT compression algorithm along with the associated I/O layer is discussed. Eventually, the performances of the algorithm is compared to other approaches.Comment: 17 pages, accepted to Astronomy and Computing special issue on astronomical file format
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