423 research outputs found

    Diamagnetism versus Paramagnetism in charged spin-1 Bose gases

    Full text link
    It has been suggested that either diamagnetism or paramagnetism of Bose gases, due to the charge or spin degrees of freedom respectively, appears solely to be extraordinarily strong. We investigate magnetic properties of charged spin-1 Bose gases in external magnetic field, focusing on the competition between the diamagnetism and paramagnetism, using the Lande-factor gg of particles to evaluate the strength of paramagnetic effect. We propose that a gas with g<1/8g<{1/\sqrt{8}} exhibits diamagnetism at all temperatures, while a gas with g>1/2g>{1/2} always exhibits paramagnetism. Moreover, a gas with the Lande-factor in between shows a shift from paramagnetism to diamagnetism as the temperature decreases. The paramagnetic and diamagnetic contributions to the total magnetization density are also calculated in order to demonstrate some details of the competition.Comment: 6 pages, 5 figure

    Structured evaluation of virtual environments for special-needs education

    Get PDF
    This paper describes the development of a structured approach to evaluate experiential and communication virtual learning environments (VLEs) designed specifically for use in the education of children with severe learning difficulties at the Shepherd special needs school in Nottingham, UK. Constructivist learning theory was used as a basis for the production of an evaluation framework, used to evaluate the design of three VLEs and how they were used by students with respect to this learning theory. From an observational field study of student-teacher pairs using the VLEs, 18 behaviour categories were identified as relevant to five of the seven constructivist principles defined by Jonassen (1994). Analysis of student-teacher behaviour was used to provide support for, or against, the constructivist principles. The results show that the three VLEs meet the constructivist principles in very different ways and recommendations for design modifications are put forward

    Multi-modalities in classroom learning environments

    Get PDF
    This paper will present initial findings from the second phase of a Horizon 2020 funded project, Managing Affective-learning Through Intelligent Atoms and Smart Interactions (MaTHiSiS). The project focusses on the use of different multi-modalities used as part of the project in classrooms across Europe. The MaTHiSiS learning vision is to develop an integrated learning platform, with re-usable learning components which will respond to the needs of future education in primary, secondary, special education schools, vocational environments and learning beyond the classroom. The system comprises learning graphs which attach individual learning goals to the system. Each learning graph is developed from a set of smart learning atoms designed to support learners to achieve progression. Cutting edge technologies are being used to identify the affect state of learners and ultimately improve engagement of learners. Much research identifies how learners engage with learning platforms (c.f. [1], [2], [3]). Not only do e-learning platforms have the capability to engage learners, they provide a vehicle for authentic classroom and informal learning [4] enabling ubiquitous and seamless learning [5] within a non-linear environment. When experiencing more enjoyable interaction learners become more confident and motivated to learn and become less anxious, especially those with learning disabilities or at risk of social exclusion [6], [13]. [7] identified the importance of understanding the affect state of learners who may experience emotions such as 'confusion, frustration, irritation, anger, rage, or even despair' resulting in disengaging with learning. The MaTHiSiS system will use a range of platform agents such as NAO robots and Kinects to measure multi-modalities that support the affect state: facial expression analysis and gaze estimation [8], mobile device-based emotion recognition [9], skeleton motion using depth sensors and speech recognition. Data has been collected using multimodal learning analytics developed for the project, including annotated multimodal recordings of learners interacting with the system, facial expression data and position of the learner. In addition, interviews with teachers and learners, from mainstream education as well as learners with profound multiple learning difficulties and autism, have been carried out to measure engagement and achievement of learners. Findings from schools based in the United Kingdom, mainstream and special schools will be presented and challenges shared

    Probiotic Pediococcus acidilactici modulates both localised intestinal- and peripheral-immunity in tilapia (Oreochromis niloticus).

    Get PDF
    The application of probiotics in aquaculture has received concerted research efforts but the localised intestinal immunological response of fish to probiotic bacteria is poorly understood. Therefore, a study was conducted to evaluate the probiotic effect of Pediococcus acidilactici on Nile tilapia (Oreochromis niloticus) with specific emphasis on intestinal health and probiotic levels as well as system level responses such as growth performance, feed utilization and haemato-immunological parameters under non-challenged conditions. Fish (9.19 ± 0.04 g) were fed either a control diet or a P. acidilactici supplemented diet (at 2.81 × 10(6) CFU g(-)(1)) for six weeks. At the end of the study the probiotic was observed to populate the intestine, accounting for ca. 3% (1.59 × 10(5) CFU g(-)(1)) of the cultivable intestinal bacterial load. Real-time PCR indicated that the probiotic treatment may potentiate the immune-responsiveness of the intestine as up-regulation of the gene expression of the pro-inflammatory cytokine TNFα was observed in the probiotic fed fish (P 0.05)

    LA TREPONEMATOSIS (YAWS) EN LAS POBLACIONES PREHISPÁNICAS DEL DESIERTO DE ATACAMA (NORTE DE CHILE)

    Full text link

    Using interdisciplinary research project collaborations as a pedagogic tool to enhance learning and teaching : a showcase with low temperature fused recycled glass for a reception desk in the new academic building at the Swansea Waterfront Innovation Quarter

    Get PDF
    This paper demonstrates how a collaboration between staff from differing subject areas within the University of Wales Trinity Saint David (UWTSD) at its Swansea Campus performed on a live project. The project was embedded in a research active field which investigated the feasibility of low temperature fused recycled glass as an architectural material, and invited undergraduate students to take part in the research within their discipline of study. The project’s initial intentions were aligned to the amendments, which occurred in June 2015, in the Sustainability Principles for the SA1 Waterfront Development also known as Swansea Waterfront Innovation Quarter (SWIQ). These amendments developed opportunities to use the creative design and environmental skills of staff and learners within UWTSD for the development of the new academic building at the Swansea Waterfront Innovation Quarter. The delivery of project outcomes cumulated with three main aims; enhanced learner experience, formation of a research active and cross-faculty group and the development of a commercially viable product. This project was bespoke as it considered the changing environment and tells a progressive story of learner engagement, a collaboration between staff and external stake holders and demonstrates the first goal and the five ways of working from the Wellbeing of Future Generation (Wales) Act

    Overview of field operations during a 2013 research expedition to the southern Beaufort Sea on the RV Araon

    Get PDF
    Research experiments conducted and preliminary findings The Expedition ARA04C is a multidisciplinary research program in the Beaufort Sea, carried out in collaboration between the Korea Polar Research Institute (KOPRI), Geological Survey of Canada (GSC), Department of Fisheries and Ocean (DFO), Monterey Bay Aquarium Research Institute (MBARI), and the Alfred Wegener Institute (AWI). The Expedition ARA04C on the IBRV Araon took place from September 6 to September 24, 2013 (Figure 0.1). Multiple research experiments were undertaken to study geological processes related to degrading permafrost, fluid flow and degassing, and associated geohazards, paleo-oceanography of the Beaufort shelf and slope region, as well as physical and chemical oceanography measurement of the Arctic Ocean linked with continuous atmospheric studies. The expedition focused on two main research areas: offshore Barrow, Alaska, from September 7 to September 9, 2013, and the Canadian Beaufort Sea from September 10 to September 24, 2013. Multichannel seismic data, in conjunction with an ocean-bottom-seismometer (OBS) study were collected to support drilling proposals especially IODP pre-proposal #806 (Dallimore et al., 2012), and to verify distribution and internal structures of the offshore permafrost occurrences (Figure 0.2). The multi-channel seismic data were acquired on the outer continental shelf of the Canadian Beaufort Sea, totaling 14 lines with ~435 line-kilometers and ~4,500 shot gathers (Chapter 3). The combined multichannel seismic and OBS data will be processed post-expedition at KOPRI and the GSC, and will allow detailed velocity analyses to investigate the permafrost signature and help mapping zones of high-velocity sediments indicative of the presence of ice (Chapter 4). Individual shot gathers collected during the multichannel seismic program show clear refraction arrivals with velocities around 2000m/s in areas of expected permafrost occurrence, and shot gathers lacked such arrivals in zones where the permafrost was predicted to be absent. It is therefore expected that the OBS data, once processed, will also show clear refracted arrivals for velocity analyses. Continuous sub-bottom profiler (SBP) and multibeam data were collected along all ship tracks for detailed subsurface imaging of sediment structures and permafrost, as well as for core-site location verification (Chapter 5 and 6). During Expedition ARA04C, more than 3000 line-kilometers of SBP data were collected, co-located with multibeam and backscatter data. These data are an essential part of the study of sub-seafloor permafrost distribution and provide insights into sediment dynamics at critical boundaries, such as the shelf edge. Along the shelf edge, the occurrence of pingo-like features (PLFs) result in a rugged landscape with thousands of PLFs piercing through the otherwise laminated sediments. More than 30 crossings of this critical shelf-edge boundary were made during this expedition, which complement data acquired in 2012 with the Huntec system and 3.5 kHz data provided by ArcticNet as part of the regional multibeam map of the study area. High resolution data provided critical new insights in deep-water fluid expulsion zones. Key new data were acquired over the area of the "Gary Knolls", where PLF structures occur at the shelf edge in water depth of only 50 to 60 m. All SBP data from this expedition will be post-processed and analyzed for the presence of sub-seafloor permafrost, occurrence of the PLF structures and indications for fluid and gas migration. Multibeam and backscatter data were collected along all ship tracks, adding to the database of existing information gathered through previous expeditions to the study region. Heat flow measurements were undertaken at eight stations (Figure 0.3) to study the thermal structure of fluid expulsion features, as well as degrading permafrost along a slope-shelf transect in the eastern Mackenzie Trough (Chapter 7). The data provide critical constraints on the distribution of sub-seafloor permafrost as well as the gas hydrate stability zone around fluid expulsion features. A very important finding is the observation made at the mud volcano in 420 m water depth, where seafloor temperatures are the highest in all observed stations, indicating active mud volcanism. Geological sampling using gravity coring and multi-coring tools was performed at strategic sites to support two research objectives. The first objective was to provide key data towards ongoing international research linked to IODP pre-proposals #753 (O'Regan et al., 2010) and #806 (Dallimore et al., 2012). The second objective was to collect core to define key seismo-stratigraphic horizons critical to the understanding of geohazards in the region (Chapter 8). In total, 21 gravity cores and 12 multi-cores were taken (Figure 0.4, Table 8.3). All cores were scanned with a multi-sensor core-logger to measure physical properties (Chapter 9). Most sediment analyses on the cores will be performed post-expedition at KOPRI, GSC, and laboratories of other University-based collaborators in Canada and Germany. Onboard, sub-samples were taken from all shallow multi-cores and selected gravity cores. On selected cores from the Canadian Beaufort study region pore-waters were extracted using rhizones. These samples will be analyzed postexpedition at MBARI. Water sampling and Conductivity-Temperature-Depth (CTD) profiling was undertaken at most core sites to study physical and chemical properties of the seawater (Figure 0.5). These station-measurements were complemented by continuous waterproperty and atmospheric measurements when the Araon was underway. Most samples taken will be analyzed post-expedition at KOPRI for DIC/TA, nutrients, DOC, and POC. The pH of seawater, underway data of pCO2, CH4, and N2O, as well as a variety of subsequent calculations is required for accurate estimates in the above listed parameters. Methane was also measured with a methane sensor attached to the CTD tool and at the mud volcano in 420 m water depth, methane concentrations of more than 100-times ocean background were seen. The methane plume was also acoustically imaged with the echo sounder systems on board the IBRV Araon. Further details on the water sampling and atmospheric measurements are given in Chapter 10 and 11

    Design of a Morphing Wing-tip

    Get PDF
    An initial design of a morphing wing-tip for a Regional Jet aircraft is developed and evaluated. The adaptive wing-tip concept is based upon a chiral type internal structure, enabling controlled cant angle orientation, camber and twist throughout the flight envelope. A baseline Turbo-Fan Aircraft configuration model is used as the benchmark to assess the device. CFD based aerodynamics are used to evaluate the required design configurations for the device at different points across the flight envelope in terms of lift/drag and bending moment distribution along the span, complemented by panel method based gust load computations. Detailed studies are performed to show how the chiral structure can facilitate the required shape changes in twist, camber and cant. Actuator requirements and limitations are assessed, along with an evaluation of the aerodynamic gains from the inclusion of the device versus power and weight penalties. For a typical mission it was found that savings of around 2% in fuel weight are possible using the morphing wing-tip device. A similar reduction in weight due to passive gust loads alleviation is also possible with a slight change of configuration

    Functional maturation of isolated neural progenitor cells from the adult rat hippocampus

    Get PDF
    Although neural progenitor cells (NPCs) may provide a source of new neurons to alleviate neural trauma, little is known about their electrical properties as they differentiate. We have previously shown that single NPCs from the adult rat hippocampus can be cloned in the presence of heparan sulphate chains purified from the hippocampus, and that these cells can be pushed into a proliferative phenotype with the mitogen FGF2 [Chipperfield, H., Bedi, K.S., Cool, S.M. & Nurcombe, V. (2002) Int. J. Dev. Biol., 46, 661-670]. In this study, the active and passive electrical properties of both undifferentiated and differentiated adult hippocampal NPCs, from 0 to 12 days in vitro as single-cell preparations, were investigated. Sparsely plated, undifferentiated NPCs had a resting membrane potential of approximate to -90 mV and were electrically inexcitable. In > 70%, ATP and benzoylbenzoyl-ATP evoked an inward current and membrane depolarization, whereas acetylcholine, noradrenaline, glutamate and GABA had no detectable effect. In Fura-2-loaded undifferentiated NPCs, ATP and benzoylbenzoyl-ATP evoked a transient increase in the intracellular free Ca2+ concentration, which was dependent on extracellular Ca2+ and was inhibited reversibly by pyridoxalphosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS), a P2 receptor antagonist. After differentiation, NPC-derived neurons became electrically excitable, expressing voltage-dependent TTX-sensitive Na+ channels, low- and high-voltage-activated Ca2+ channels and delayed-rectifier K+ channels. Differentiated cells also possessed functional glutamate, GABA, glycine and purinergic (P2X) receptors. Appearance of voltage-dependent and ligand-gated ion channels appears to be an important early step in the differentiation of NPCs
    corecore