232 research outputs found

    Reverse engineering of a fixed wing unmanned aircraft 6-DoF model for navigation and guidance applications

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    A method for deriving the parameters of a six-degree-of-freedom (6-DoF) aircraft dynamics model by adopting reverse engineering techniques is presented. The novelty of the paper is the adaption of the 6-DoF Aircraft Dynamics Model (ADM) as a virtual sensor integrated in a low-cost navigation and guidance system designed for small Unmanned Aircraft (UA). The mass and aerodynamic properties of the JAVELIN UA are determined with the aid of an accurate 3D scanning and CAD processing. For qualitatively assessing the calculated ADM, a trajectory with high dynamics is simulated for the JAVELIN UA and compared with that of a published 6-DoF model of the AEROSONDE UA. Additionally, to confirm the validity of the approach, reverse engineering procedures are applied to a published CAD model of the AEROSONDE UA aiding to the calculation of the associated 6-DoF model parameters. A spiral descent trajectory is generated using both the published and calculated parameters of the AEROSONDE UA and a comparative analysis is performed that validates the methodology. The accurate knowledge of the ADM is then utilised in the development of a virtual sensor to augment the UA navigation and guidance system in case of primary navigation sensor outages

    Children with lesbian parents: A community study

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    Existing research on children with lesbian parents is limited by reliance on volunteer or convenience samples. The present study examined the quality of parent-child relationships and the socio-emotional and gender development of a community sample of 7-year-old children with lesbian parents. Families were recruited through the Avon Longitudinal Study of Parents and Children, a geographic population study of 14,000 mothers and their children. Thirty-nine lesbian-mother families, 74 two-parent heterosexual families, and 60 families headed by single heterosexual mothers were compared on standardized interview and questionnaire measures administered to mothers, co-mothers/fathers, children, and teachers. Findings are in line with those of earlier investigations showing positive mother-child relationships and well-adjusted children

    Designs for Heritage Language Learning: A Photography project in the UK Supplementary Education

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    Supplementary Schools in the UK offer educational opportunities for children and young people outside mainstream school provision. The paper reports an enquiry undertaken by practitioners in Greek Supplementary Schools in the UK to explore how features of mobile technologies may be leveraged to foster heritage language learning. It draws on the view that mobile learning can be a way for learners to explore the language informally and direct their own development (Kukulska-Hulme, 2015) and may also shape the learners’ ‘habits of mind’ (Wong, 2012, p.22) in learning—and consequently their language competencies. The project #ItsAllGreekToUS set to investigate how to create learning designs to incorporate effective use of mobile technologies within language learning and teaching. It draws on action research orientation and uses the idea of ‘Bring Your Own Device’ (BYOD) (JISC, 2013) in educational settings. The study involved several sessions around the concept of ‘loanwords’ and representations of this vocabulary in artefacts created with the use of mobile phones and a popular photography application (e.g. Pinterest). The participants were fourteen students (12-13s) attending a pre-GCSE class in a Greek School in London and nine students (12-14s) attending a GCSE class in a Greek School in Leicester. Evidence from user-generated content, the pupils’ views around the project and the practitioners’ observations are considered. The paper will discuss how students’ practices associated with mobile technologies are integrated into teachers’ practice. Particular attention will be drawn to designing language learning by blending traditional language classroom practices along incorporating the practices of sharing and curating content, as well as allowing ‘visibility’ through artefacts created by the learners

    Clinical and cost effectiveness of single stage compared with two stage revision for hip prosthetic joint infection (INFORM):pragmatic, parallel group, open label, randomised controlled trial

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    OBJECTIVES: To determine whether patient reported outcomes improve after single stage versus two stage revision surgery for prosthetic joint infection of the hip, and to determine the cost effectiveness of these procedures. DESIGN: Pragmatic, parallel group, open label, randomised controlled trial. SETTING: High volume tertiary referral centres or orthopaedic units in the UK (n=12) and in Sweden (n=3), recruiting from 1 March 2015 to 19 December 2018. PARTICIPANTS: 140 adults (aged ≥18 years) with a prosthetic joint infection of the hip who required revision (65 randomly assigned to single stage and 75 to two stage revision). INTERVENTIONS: A computer generated 1:1 randomisation list stratified by hospital was used to allocate participants with prosthetic joint infection of the hip to a single stage or a two stage revision procedure. MAIN OUTCOME MEASURES: The primary intention-to-treat outcome was pain, stiffness, and functional limitations 18 months after randomisation, measured by the Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) score. Secondary outcomes included surgical complications and joint infection. The economic evaluation (only assessed in UK participants) compared quality adjusted life years and costs between the randomised groups. RESULTS: The mean age of participants was 71 years (standard deviation 9) and 51 (36%) were women. WOMAC scores did not differ between groups at 18 months (mean difference 0.13 (95% confidence interval -8.20 to 8.46), P=0.98); however, the single stage procedure was better at three months (11.53 (3.89 to 19.17), P=0.003), but not from six months onwards. Intraoperative events occurred in five (8%) participants in the single stage group and 20 (27%) in the two stage group (P=0.01). At 18 months, nine (14%) participants in the single stage group and eight (11%) in the two stage group had at least one marker of possible ongoing infection (P=0.62). From the perspective of healthcare providers and personal social services, single stage revision was cost effective with an incremental net monetary benefit of £11 167 (95% confidence interval £638 to £21 696) at a £20 000 per quality adjusted life years threshold (£1.0; $1.1; €1.4). CONCLUSIONS: At 18 months, single stage revision compared with two stage revision for prosthetic joint infection of the hip showed no superiority by patient reported outcome. Single stage revision had a better outcome at three months, fewer intraoperative complications, and was cost effective. Patients prefer early restoration of function, therefore, when deciding treatment, surgeons should consider patient preferences and the cost effectiveness of single stage surgery. TRIAL REGISTRATION: ISRCTN registry ISRCTN10956306.RD&E staff can access the full-text of this article by clicking on the 'Additional Link' above and logging in with NHS OpenAthens if prompted.Unknow

    The quest for the solar g modes

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    Solar gravity modes (or g modes) -- oscillations of the solar interior for which buoyancy acts as the restoring force -- have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well observed acoustic modes (or p modes). The high amplitude of the g-mode eigenfunctions in the core and the evanesence of the modes in the convection zone make the modes particularly sensitive to the physical and dynamical conditions in the core. Owing to the existence of the convection zone, the g modes have very low amplitudes at photospheric levels, which makes the modes extremely hard to detect. In this paper, we review the current state of play regarding attempts to detect g modes. We review the theory of g modes, including theoretical estimation of the g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the techniques that have been used to try to detect g modes. We review results in the literature, and finish by looking to the future, and the potential advances that can be made -- from both data and data-analysis perspectives -- to give unambiguous detections of individual g modes. The review ends by concluding that, at the time of writing, there is indeed a consensus amongst the authors that there is currently no undisputed detection of solar g modes.Comment: 71 pages, 18 figures, accepted by Astronomy and Astrophysics Revie

    Uncoupling the functions of CALM in VAMP sorting and clathrin-coated pit formation.

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    CALM (clathrin assembly lymphoid myeloid leukemia protein) is a cargo-selective adaptor for the post-Golgi R-SNAREs VAMPs 2, 3, and 8, and it also regulates the size of clathrin-coated pits and vesicles at the plasma membrane. The present study has two objectives: to determine whether CALM can sort additional VAMPs, and to investigate whether VAMP sorting contributes to CALM-dependent vesicle size regulation. Using a flow cytometry-based endocytosis efficiency assay, we demonstrate that CALM is also able to sort VAMPs 4 and 7, even though they have sorting signals for other clathrin adaptors. CALM homologues are present in nearly every eukaryote, suggesting that the CALM family may have evolved as adaptors for retrieving all post-Golgi VAMPs from the plasma membrane. Using a knockdown/rescue system, we show that wild-type CALM restores normal VAMP sorting in CALM-depleted cells, but that two non-VAMP-binding mutants do not. However, when we assayed the effect of CALM depletion on coated pit morphology, using a fluorescence microscopy-based assay, we found that the two mutants were as effective as wild-type CALM. Thus, we can uncouple the sorting function of CALM from its structural role

    Digital prosumption labour on social media in the context of the capitalist regime of time

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    So-called social media such as Facebook, Twitter, YouTube, Weibo and LinkedIn are an expression of changing regimes of time in capitalist society. This paper discusses how corporate social media are related to the capitalist organization of time and the changes this organization is undergoing. It uses social theory for conceptualizing changes of society and its time regime and how these changes shape social media. These changes have been described with notions such as prosumption, consumption labour, play labour (playbour) and digital labour. The paper contextualizes digital labour on social media with the help of a model of society that distinguishes three subsystems (the economy, politics, culture) and three forms of power (economic, political, culture). In modern society, these systems are based on the logic of the accumulation of power and the acceleration of accumulation. The paper discusses the role of various dimensions of time in capitalism with the help of a model that is grounded in Karl Marx’s works. It points out the importance of the category of time for a labour theory of value and a digital labour theory of value. Social media are expressions of the changing time regimes that modern society has been undergoing, especially in relation to the blurring of leisure and labour time (play labour), production and consumption time (prosumption), new forms of absolute and relative surplus value production, the acceleration of consumption with the help of targeted online advertising and the creation of speculative, future-oriented forms of fictitious capital
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