2,034 research outputs found

    L2P NOOB: Examining Tutorials in Digital Games

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    It has been well-noted that contemporary digital games tend to design for a relatively high skill threshold engineered to appease a well-entrenched and digitally literate audience (Hayes, 2005). Such design practices, however, serve to disenfranchise new and novice players wanting to learn to play. This novice-expert divide is a significant barrier to entry for individuals wanting to play digital games, and given that digital games are seeing increased use in pedagogical contexts (Akilli, 2007; Becker, 2007; Nieborg, 2011; Shelton, Satwicz, & Caswell, 2011; Ulicsak, 2010), such skill-based barriers further complicate the seamless incorporation of digital games into the classroom. In an effort to explore how we might bridge the gap between new and weathered players, I created three tutorials for World of Warcraft (2004) in an attempt to improve the existing tutorials for newer entrants to the game. These new tutorials offered different modalities of instruction, as well as instructional strategies in assisting newer players. Tutorials were designed using the Structured Sound Functions (SSF) model of instructional design, following the Attentional Control Theory of Multimedia Learning (ACTML). The tutorials were then analyzed for their effects on play outcomes, player engagement, and player motivations using the Dick and Carey (2011) three-stage model of formative evaluation. This work thus makes two important contributions. First, this research conducts a much-needed in-depth study of game tutorials, which is an area yet to be well-charted in the disciplines of either education or games studies. Secondly, by analyzing the results of the formative evaluation, I conclude that players react favorably to a faded or ā€œjust-in-timeā€ instructional strategyā€”an approach to player scaffolding which showed significantly increased motivation for play, engagement, and play mastery among novice participants. Implications for game design and future research are discussed

    Using a Cubic Equation of State to Identify Optimal Working Fluids for an ORC Operating with Two-Phase Expansion Using a Twin-Screw Expander

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    For waste-heat recovery applications, operating an organic Rankine cycle (ORC) with two-phase expansion has been shown to increase the utilisation of the waste-heat stream, leading to a higher power output compared to a conventional ORC with single-phase expansion. However, unlike the conventional ORC, working-fluid selection for an ORC operating with two-phase expansion has not been explored in detail within the literature. Therefore, the aim of this paper is to explore which working-fluid parameters make a particular working fluid suitable for this type of cycle. This is conducted by coupling a thermodynamic model of the cycle with the Peng-Robinson cubic equation of state. Moreover, the effect of the expander volumetric ratio on the expander isentropic efficiency is accounted for using a performance model for a twin-screw expander. Ultimately, the adopted approach allows the effect of the working-fluid parameters, namely the critical temperature and ideal specific-heat capacity, on both the expander performance and the cycle to be evaluated in a generalised way. For the investigation, 15 theoretical working fluids are defined, covering five different critical temperatures, with a negatively-sloped, vertical and positively-sloped saturated vapour line respectively. The 15 working fluids are selected as they represent the feasible design space occupied by existing ORC working fluids. For each fluid, a cycle optimisation is completed for different heat-source temperatures ranging between 80 and 200 Ā°C. The objective is to identify the optimal cycle operating conditions that result in maximum power output from the system. By analysing the results, the optimal characteristics of a working fluid are obtained, and this information can be used to identify physical working fluids which are good candidates for a particular heat-source temperature. In the final part of this paper, the cycle optimisation is repeated for the physical working fluids identified, thus validating the suitability of the approach developed. Ultimately, the results can help to narrow down the search space when considering working fluids for an ORC operating with two-phase expansion

    Functional Significance of CD57 Expression on Human NK Cells and Relevance to Disease.

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    Historically, human NK cells have been identified as CD3(-)CD56(+)CD16(Ā±) lymphocytes. More recently it has been established that CD57 expression defines functionally discrete sub-populations of NK cells. On T cells, CD57 expression has been regarded as a marker of terminal differentiation and (perhaps wrongly) of anergy and senescence. Similarly, CD57 expression seems to identify the final stages of peripheral NK cell maturation; its expression increases with age and is associated with chronic infections, particularly human cytomegalovirus infection. However, CD57(+) NK cells are highly cytotoxic and their presence seems to be beneficial in a number of non-communicable diseases. The purpose of this article is to review our current understanding of CD57 expression as a marker of NK cell function and disease prognosis, as well as to outline areas for further research

    Correlates of English local government use of the planning system to regulate hot food takeaway outlets: a cross-sectional analysis

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    Background: Greater neighbourhood takeaway food outlet access has been associated with increased takeaway food consumption and higher body weight. National planning guidelines in England suggest that urban planning could promote healthier food environments through takeaway food outlet regulation, for example by restricting the proliferation of outlets near schools. It is unknown how geographically widespread this approach is, or local characteristics associated with its use. We aimed to address these knowledge gaps. Methods: We used data from a complete review of planning policy documents adopted by local government areas in England (nā€‰=ā€‰325), which contained policies for the purpose of takeaway food outlet regulation. This review classified local government area planning policies as having a health (diet or obesity) or non-health focus. We explored geographical clustering of similar planning policies using spatial statistics. We used multinomial logistic regression models to investigate whether the odds of planning policy adoption varied according to local characteristics, for example the proportion of children with excess weight or the current number of takeaway food outlets. Results: We observed clusters of local government areas with similar adopted planning policies in the North East, North West, and Greater London regions of England. In unadjusted logistic regression models, compared to local government areas with the lowest, those with highest proportion of 10ā€“11ā€‰year olds with excess weight (OR: 25.31; 95% CI: 6.74, 94.96), and takeaway food outlet number (OR: 54.00; 95% CI: 6.17, 472.41), were more likely to have a health-focused planning policy, than none. In models adjusted for deprivation, relationships for excess weight metrics were attenuated. Compared to local government areas with the lowest, those with the highest takeaway food outlet number remained more likely to have a health-focused planning policy, than none (OR: 16.98; 95% CI: 1.44, 199.04). When local government areas were under Labour political control, predominantly urban, and when they had more geographically proximal and statistically similar areas in the same planning policy status category, they were also more likely to have health-focused planning policies. Conclusions: Planning policies for the purpose of takeaway food outlet regulation with a health focus were more likely in areas with greater numbers of takeaway food outlets and higher proportions of children with excess weight. Other characteristics including Labour political control, greater deprivation and urbanisation, were associated with planning policy adoption, as were the actions of similar and nearby local government areas. Further research should engage with local policymakers to explore the drivers underpinning use of this approach

    Experimental simulation of closed timelike curves

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    Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics-essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence

    Differential activation of CD57-defined natural killer cell subsets during recall responses to vaccine antigens

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    Natural killer (NK) cells contribute to the effector phase of vaccine-induced adaptive immune responses, secreting cytokines and releasing cytotoxic granules. The proportion of responding NK cells varies between individuals and by vaccine, suggesting that functionally discrete subsets of NK cells with different activation requirements may be involved. Here, we have used responses to individual components of the DTP vaccine [tetanus toxoid (TT), diphtheria toxoid (DT), whole cell inactivated pertussis] to characterize the NK cell subsets involved in interleukin-2-dependent recall responses. Culture with TT, DT or pertussis induced NK cell CD25 expression and interferon-Ī³ production in previously vaccinated individuals. Responses were the most robust against whole cell pertussis, with responses to TT being particularly low. Functional analysis of discrete NK cell subsets revealed that transition from CD56bright to CD56dim correlated with increased responsiveness to CD16 cross-linking, whereas increasing CD57 expression correlated with a loss of responsiveness to cytokines. A higher frequency of CD56dim CD57āˆ’ NK cells expressed CD25 and interferon-Ī³ following stimulation with vaccine antigen compared with CD56dim CD57+ NK cells and made the largest overall contribution to this response. CD56dim CD57int NK cells represent an intermediate functional phenotype in response to vaccine-induced and receptor-mediated stimuli. These findings have implications for the ability of NK cells to contribute to the effector response after vaccination and for vaccine-induced immunity in older individuals

    MPSoCs for Reconfigurable Modular Spacecraft

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    Modular, reconfigurable spacecraft offer a new approach to extending mission capability and maximising the lifetime of a spacecraft. Future uses of space robotics such as in-orbit construction and servicing allow faulty or obsolete parts of a modular spacecraft to be replaced by servicer spacecraft that dock with their targets and perform upgrades and maintenance. Such manoeuvres will require a high degree of autonomy from both platforms and thus will need to leverage high-performance onboard computing for both the robotic control and manipulation of service spacecraft but also for managing Thales Alenia Space in the UK (TAS UK) and The University of York (UoY) are involved in projects towards this goal and are collaborating to research autonomous network reconfiguration and fault tolerance of the onboard network based on existing space technology (SpaceWire, SpaceFibre). Both organisations have identified FPGA based MPSoCs as a solution for providing the high-performance computing that autonomous robotic systems require, using the FPGA fabric for mission-phase related hardware accelerators (e.g. vision soft co- processors) that can be swapped as the construction or maintenance task demands. In this presentation we will describe the modular spacecraft avionics unit that TAS UK is developing for the H2020 MOSAR project. This is based on the Xilinx Ultrascale+ MPSoC and uses the ā€œbig-littleā€ architecture to provide a split between the spacecraft moduleā€™s mission functionality (executing on the ā€œbigā€ quad-core A53) and the support functions to provide: the communication network, module-to-module docking management and the module power management functions of the spacecraft (implemented on the ā€œlittleā€ dual-core R5 cores). Details on our development of an AXI4 compatible SpaceWire and RMAP IP core will also be included. RMAP forms an important part of the MOSAR fault management strategy and this core allows processor-transparent RMAP access to the full MPSoC address range, with automatic DMA descriptors for all other SpaceWire traffic. The AXI4 interface simply allows it to be dropped into any Ultrascale+, Zynq 7000 and NG-ultra based design and several configuration options allow options such as SpW front end type (oversampling /clock recovery) and output data path width (32-bit/16bit) to be selected. We will also present details of research by the University of York on using RMAP in a MPSoC environment. Access to the full address space of a MPSoC via RMAP brings security and fault management concerns to complex SoCs and hardware security based approaches (e.g. ARMā€™s TrustZone) could be used in future MP- SoC architectures to protect against damage by either corrupt RMAP packets, damage from failure modes of RMAP initiators or malicious/compromised spacecraft modules. To tackle autonomy challenges UoY is cur- rently developing a reasoner based, reconfigurable modular robotic platform that can cope with uncertain environments that arise in space applications using FPGA based MPSoC and soft-processor technologies. MOSAR has received funding from the European Unionā€™s Horizon 2020 research and innovation programme under Grant agreement No. 821996. Part of this work is funded by EPSRC and Innovate UK under grant KTP12066

    MicroRNA-143 activation regulates smooth muscle and endothelial cell crosstalk in pulmonary arterial hypertension

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    Rationale: The pathogenesis of PAH remains unclear. The four microRNAs representing the miR-143 and miR-145 stem loops are genomically clustered. Objective: To elucidate the transcriptional regulation of the miR-143/145 cluster, and the role of miR-143 in PAH. Methods and Results: We identified the promoter region that regulates miR-143/145 miRNA expression in pulmonary artery smooth muscle cells (PASMCs). We mapped PAH-related signalling pathways, including estrogens receptor (ER), liver X factor/retinoic X receptor (LXR/RXR), TGF-Ī² (Smads), and hypoxia (HRE) that regulated levels of all pri-miR stem loop transcription and resulting miRNA expression. We observed that miR-143-3p is selectively upregulated compared to miR-143-5p during PASMC migration. Modulation of miR-143 in PASMCs significantly altered cell migration and apoptosis. In addition, we found high abundance of miR-143-3p in PASMCs-derived exosomes. Using assays with pulmonary arterial endothelial cells (PAECs) we demonstrated a paracrine pro-migratory and pro-angiogenic effect of miR-143-3p enriched exosomes from PASMC. Quantitative PCR and in situ hybridisation showed elevated expression of miR-143 in calf models of PAH as well as in samples from PAH patients. Moreover, in contrast to our previous findings that had not supported a therapeutic role in vivo, we now demonstrate a protective role for miR-143 in experimental PH in vivo in miR-143-/- and antimiR143-3p-treated mice exposed to chronic hypoxia in both preventative and reversal settings. Conclusions: MiR-143-3p modulated both cellular and exosome-mediated responses in pulmonary vascular cells, while inhibition of miR-143-3p blocked experimental PH. Taken together these findings confirm an important role for the miR-143/145 cluster in PAH pathobiology
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