1,317 research outputs found

    A Psychophysical Experiment Regarding Components of the Plausibility Illusion

    Get PDF
    We report on the design and results of an experiment investigating factors influencing Slater’s Plausibility Illusion (Psi) in virtual environments. Slater proposed Psi and Place Illusion (PI) as orthogonal components of virtual experience which contribute to realistic response in a VE. PI corresponds to the traditional conception of presence as “being there,” so there exists a substantial body of previous research relating to PI, but very little relating to Psi. We developed this experiment to investigate the components of plausibility illusion using subjective matching techniques similar to those used in color science. Twenty-one participants each experienced a scenario with the highest level of coherence (the extent to which a scenario matches user expectations and is internally consistent), then in eight different trials chose transitions from lower-coherence to higher-coherence scenarios with the goal of matching the level of Psi they felt in the highest-coherence scenario. At each transition, participants could change one of the following coherence characteristics: the behavior of the other virtual humans in the environment, the behavior of their own body, the physical behavior of objects, or the appearance of the environment. Participants tended to choose improvements to the virtual body before any other improvements. This indicates that having an accurate and well-behaved representation of oneself in the virtual environment is the most importa

    Оборудование для испытания листовых конструкционных материалов при двухосном растяжении. Сообщение 1. Испытания односторонним давлением рабочей среды

    Get PDF
    Рассмотрены конструктивные особенности оборудования для исследования прочности и закономерностей разрушения листовых конструкционных материалов при двухосном растяжении путем нагружения образцов односторонним давлением рабочей среды. Предложены решения ряда проблем методического характера, связанных с испытаниями при высоких уровнях давления рабочей среды, что позволяет обеспечить необходимые режимы охлаждения образцов, снизить уровень энергии разрушения, повысить надежность и безопасность испытаний.Розглянуто конструктивні особливості устаткування для дослідження міцності і закономірностей руйнування листових конструкційних матеріалів при двовісному розтязі зразків одностороннім тиском робочого середовища. Запропоновано рішення ряду проблем методичного характеру, що пов’язані з випробуваннями при високих рівнях тиску робочого середовища. Це дозволить забезпечити необхідні режими охолодження зразків, знизити рівень енергії руйнування, підвищити надійность та безпеку випробувань.Design features of the equipment for studying strength and regularities of fracture of sheet structural materials in biaxial tension by subjecting specimens to one-sided pressure of a working medium are considered. Solutions were suggested for a number of methodological problems related to testing at high levels of pressure of a working medium. These solutions make it possible to provide necessary conditions of cooling of specimens, lower the level of fracture energy, and improve reliability and safety of the tests

    Population genetics in compressible flows

    Full text link
    We study competition between two biological species advected by a compressible velocity field. Individuals are treated as discrete Lagrangian particles that reproduce or die in a density-dependent fashion. In the absence of a velocity field and fitness advantage, number fluctuations lead to a coarsening dynamics typical of the stochastic Fisher equation. We then study three examples of compressible advecting fields: a shell model of turbulence, a sinusoidal velocity field and a linear velocity sink. In all cases, advection leads to a striking drop in the fixation time, as well as a large reduction in the global carrying capacity. Despite localization on convergence zones, one species goes extinct much more rapidly than in well-mixed populations. For a weak harmonic potential, one finds a bimodal distribution of fixation times. The long-lived states in this case are demixed configurations with a single boundary, whose location depends on the fitness advantage.Comment: 10 pages, 5 figures, submitte

    A new cell primo-culture method for freshwater benthic diatom communities

    Get PDF
    A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3: cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method, producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied. Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples andindustrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives

    Urocortin, a CRF-like peptide, restores key indicators of damage in the substantia nigra in a neuroinflammatory model of Parkinson's disease

    Get PDF
    We have recently observed that the corticotrophin releasing hormone (CRF) related peptide urocortin (UCN) reverses key features of nigrostriatal damage in the hemiparkinsonian 6-hydroxydopamine lesioned rat. Here we have studied whether similar effects are also evident in the lipopolysaccaride (LPS) neuroinflammatory paradigm of Parkinson's disease (PD). To do this we have measured restoration of normal motor behaviour, retention of nigral dopamine (DA) and also tyrosine hydroxylase (TH) activity. Fourteen days following intranigral injections of LPS and UCN, rats showed only modest circling after DA receptor stimulation with apomorphine, in contrast to those given LPS and vehicle where circling was pronounced. In separate experiments, rats received UCN seven days following LPS, and here apomorphine challenge caused near identical circling intensity to those that received LPS and UCN concomitantly. In a similar and consistent manner with the preservation of motor function, UCN 'protected' the nigra from both DA depletion and loss of TH activity, indicating preservation of DA cells. The effects of UCN were antagonised by the non-selective CRF receptor antagonist α-helical CRF and were not replicated by the selective CRF2 ligand UCN III. This suggests that UCN is acting via CRF1 receptors, which have been shown to be anti-inflammatory in the periphery. Our data therefore indicate that UCN is capable of maintaining adequate nigrostriatal function in vivo, via CRF1 receptors following a neuro-inflammatory challenge. This has potential therapeutic implications in PD

    Glucagon-like peptide 1 receptor stimulation reverses key deficits in distinct rodent models of Parkinson's disease

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>It has recently become apparent that neuroinflammation may play a significant role in Parkinson's disease (PD). This is also the case in animal paradigms of the disease. The potential neuroprotective action of the glucagon-like peptide 1 receptor (GLP-1R) agonist exendin-4 (EX-4), which is protective against cytokine mediated apoptosis and may stimulate neurogenesis, was investigated In paradigms of PD.</p> <p>Methods</p> <p>Two rodent 'models' of PD, 6-hydroxydopamine (6-OHDA) and lipopolysaccaride (LPS), were used to test the effects of EX-4. Rats were then investigated <it>in vivo </it>and <it>ex vivo </it>with a wide range of behavioural, neurochemical and histological tests to measure integrity of the nigrostriatal system.</p> <p>Results</p> <p>EX-4 (0.1 and 0.5 μg/kg) was given seven days after intracerebral toxin injection. Seven days later circling behaviour was measured following apomorphine challenge. Circling was significantly lower in rats given EX-4 at both doses compared to animals given 6-OHDA/LPS and vehicle. Consistent with these observations, striatal tissue DA concentrations were markedly higher in 6-OHDA/LPS + EX-4 treated rats versus 6-OHDA/LPS + vehicle groups, whilst assay of L-DOPA production by tyrosine hydroxylase was greatly reduced in the striata of 6-OHDA/LPS + vehicle rats, but this was not the case in rats co-administered EX-4. Furthermore nigral TH staining recorded in 6-OHDA/LPS + vehicle treated animals was markedly lower than in sham-operated or EX-4 treated rats. Finally, EX-4 clearly reversed the loss of extracellular DA in the striata of toxin lesioned freely moving rats.</p> <p>Conclusion</p> <p>The apparent ability of EX-4 to arrest progression of, or even reverse nigral lesions once established, suggests that pharmacological manipulation of the GLP-1 receptor system could have substantial therapeutic utility in PD. Critically, in contrast to other peptide agents that have been demonstrated to possess neuroprotective properties in pre-clinical models of PD, EX-4 is in current clinical use in the management of type-II diabetes and freely crosses the blood brain barrier; hence, assessment of the clinical efficacy of EX-4 in patients with PD could be pursued without delay.</p

    Проблемы увеличения продуктивности АПК в Украине и пути повышения его потенциала

    Get PDF
    Целью статьи является изучение причин снижения показателей продуктивности в агропромышленном комплексе и путей повышения продуктивности сельскохозяйственных культур

    Aging Skin: Nourishing from Out-In. Lessons from Wound Healing

    Get PDF
    Skin lesion therapy, peculiarly in the elderly, cannot be isolated from understanding that the skin is an important organ consisting of different tissues. Furthermore, dermis health is fundamental for epidermis integrity, and so adequate nourishment is mandatory in maintaining skin integrity. The dermis nourishes the epidermis, and a healthy epidermis protects the dermis from the environment, so nourishing the dermis through the epidermal barrier is a technical problem yet to be resolved. This is also a consequence of the laws and regulations restricting cosmetics, which cannot have properties that pass the epidermal layer. There is higher investment in cosmetics than in the pharmaceutical industry dealing with skin therapies, because the costs of drug registration are enormous and the field is unprofitable. Still, wound healing may be seen as an opportunity to “feed” the dermis directly. It could also verify whether providing substrates could promote efficient healing and test optimal skin integrity maintenance, if not skin rejuvenation, in an ever aging population

    Mapping the UK thesis landscape: Phase 1 project report for Unlocking Thesis Data

    Get PDF
    This report details the work (April-July 2015) of Unlocking Thesis Data, where the project carried out a survey of EThOS institutions, interviewed staff at six universities for more in-depth case studies, and synthesised the findings. Overall, there is much appetite for applying DOIs to theses and their data (which includes datasets, software components and other non-textual supplementary files) and ORCiDs to research students. Glasgow, Southampton and East London universities each minted a DOI for an existing thesis, demonstrating the viability of our intent, but the case studies showed there are constraints in both processes and technologies to be addressed before persistent identifiers (PID) for theses can be a nationwide reality in the UK. The project makes five recommendations for further work in a second phase: 1. Hold at least three thesis “clinics” to investigate opportunities and barriers to assigning DOI and ORCiD identifiers in UK universities 2. Engage with system suppliers/vendors to identify opportunities for enhancing software with required PIDs 3. Consult with EThOS formally to understand what needs to change in EThOS systems and processes to harvest and display PIDs and related metadata for theses and their data 4. Evaluate approaches to updating UKETD profile, initially in EPrints, before planning software enhancements 5. Investigate requirements and solutions for those institutions that use EThOS as their first-point repository
    corecore