108 research outputs found

    Experience based action planning for environmental manipulation in autonomous robotic systems

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    The ability for autonomous robots to plan action sequences in order to manipulate their environment to achieve a specific goal is of vital importance for agents which are deployed in a vast number of situations. From domestic care robots to autonomous swarms of search and rescue robots there is a need for agents to be able to study, reason about, and manipulate their environment without the oversight of human operators. As these robots are typically deployed in areas inhabited and organised by humans it is likely that they will encounter similar objects when going about their duties, and in many cases the objects encountered are likely to be arranged in similar ways relative to one another. Manipulation of the environment is an incredibly complex task requiring vast amounts of computation to generate a suitable state of actions for even the simplest of tasks. To this end we explore the application of memory based systems to environment manipulation planning. We propose new search techniques targeted at the problem of environmental manipulation for search and rescue, and recall techniques aimed at allowing more complex planning to take place with lower computational cost. We explore these ideas from the perspective of autonomous robotic systems deployed for search and rescue, however the techniques presented would be equally valid for robots in other areas, or for virtual agents interacting with cyber-physical systems

    A longitudinal study of muscle rehabilitation in the lower leg after cast removal using Magnetic Resonance Imaging and strength assessment

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    Acknowledgements We thank the A&E nurses and plaster technicians for identifying suitable patients, the MRI radiographers for performing the scanning, Dr Scott Semple for invaluable help in some of the pilot studies and Mr E. C. Stevenson for constructing the footrest used in the scanner. We are very grateful to the dedicated patients themselves who gave considerable amounts of time to come in for scanning, exercise and assessment during the course of this study.Peer reviewedPublisher PD

    Patterns of satellite tagged hen harrier disappearances suggest widespread illegal killing on British grouse moors

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    Natural England commenced a Hen Harrier Recovery Project in 2002. This tracking study was funded exclusively by Natural England and is part of their on-going work on hen harrier conservation. We thank Hamish Smith and staff at the Hawk and Owl Trust for contributing data from four hen harriers they have tracked. We are grateful for the time of many volunteers in the field who monitored and searched for harriers: Pat Martin, Gavin Craggs, Pete Davies, Derek Hayward, Martin Davison, Mick Carroll, Paul Howarth, Ian Thomson, and Elsie Ashworth. We thank Judith Smith and Phil Skinner for sponsoring tags. Also we would like to thank the Wildlife Crime Officers in Lancashire, Yorkshire, Co Durham and Northumberland for their assistance. Thanks also to Jeremy Wilson and Pat Thompson for useful comments on this manuscript. We are grateful to staff at Microwave Telemetry Inc. and CLS France for data archiving. The complete data sets analysed in this study are not publicly available due to the sensitivity of the locational data but are available from the corresponding author on reasonable request and with permission of Natural England. The source data for Figs. 1 and 2 have been provided as a Source Data file.Peer reviewedPublisher PD

    Evaluating Bayesian stable isotope mixing models of wild animal diet and the effects of trophic discrimination factors and informative priors

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    Funding information University of Exeter; CONICYT, Grant/ Award Number: 3190800; ERC, Grant/ Award Number: 310820Peer reviewedPublisher PD

    Hybrid Societies : Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems

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    Hybrid societies are self-organizing, collective systems, which are composed of different components, for example, natural and artificial parts (bio-hybrid) or human beings interacting with and through technical systems (socio-technical). Many different disciplines investigate methods and systems closely related to the design of hybrid societies. A stronger collaboration between these disciplines could allow for re-use of methods and create significant synergies. We identify three main areas of challenges in the design of self-organizing hybrid societies. First, we identify the formalization challenge. There is an urgent need for a generic model that allows a description and comparison of collective hybrid societies. Second, we identify the system design challenge. Starting from the formal specification of the system, we need to develop an integrated design process. Third, we identify the challenge of interdisciplinarity. Current research on self-organizing hybrid societies stretches over many different fields and hence requires the re-use and synthesis of methods at intersections between disciplines. We then conclude by presenting our perspective for future approaches with high potential in this area

    Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management

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    Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems

    Differential protein phosphorylation in 3T3-L1 adipocytes in response to insulin versus platelet-derived growth factor

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    Insulin regulates glucose metabolism in adipocytes via a phosphatidylinositide 3-kinase (PI3K)-dependent pathway that appears to involve protein phosphorylation. However, the generation of phosphoinositides is not sufficient for insulin action, and it has been suggested that insulin regulation of glucose metabolism may involve both PI3K-dependent and -independent pathways, the latter being insulin specific. To test this hypothesis, we have designed a phosphoprotein screen to study insulin-specific phosphoproteins that may be either downstream or in parallel to PI3K. Nineteen insulin-regulated phosphospots were detected in the cytosol and high speed pellet fractions, only six of which were significantly regulated by platelet-derived growth factor. Importantly, almost all (92%) of the insulin-specific phosphoproteins identified using this approach were sensitive to the PI3K inhibitor wortmannin. Thus, we obtained no evidence for an insulin-specific, PI3K-independent signaling pathway. A large proportion (62%) of the insulin-specific phosphoproteins were enriched in the same high speed pellet fraction to which PI3K was recruited in response to insulin. Thus, our data suggest that insulin specifically stimulates the phosphorylation of a novel subset of downstream targets and this may in part be because of the unique localization of PI3K in response to insulin in adipocytes

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≄1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≀6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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