457 research outputs found

    Evaluating the Potential of the Original Texas Land Survey for Mapping Historical Land and Vegetation Cover

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    © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).This paper reports on research to evaluate the potential of Original Texas Land Survey (OTLS) to generate information that can be used to quantitatively map historical vegetation cover and analyse pertinent aspects of vegetation ecology. Research was conducted in Brazos County in east-central Texas. OTLS data are easy to acquire and convert to geo-referenced autecological information. Reconstructing and mapping vegetation and land cover, conducting vegetation- and species-site analyses with to soil-ecological maps, reconstructing vegetation assemblages and forest structure can be easily accomplished. Due to the irregular surveying framework used by OTLS, mapping gradational grassland-savannah ecotone boundaries is impracticable. View Full-Tex

    Towards agent-based crowd simulation in airports using games technology

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    We adapt popular video games technology for an agent-based crowd simulation in an airport terminal. To achieve this, we investigate the unique traits of airports and implement a virtual crowd by exploiting a scalable layered intelligence technique in combination with physics middleware and a socialforces approach. Our experiments show that the framework runs at interactive frame-rate and evaluate the scalability with increasing number of agents demonstrating navigation behaviour

    Axion-Photon Conversion in 3D Media and Astrophysical Plasmas

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    With axions now a primary candidate for dark matter, understanding their indirect astrophysical signatures is of paramount importance. Key to this is the production of photons from axions in magnetised astrophysical plasmas. While simple formulae for axion-photon mixing in 1D have been sketched several decades ago, there has recently been renewed interest in robust calculations for this process in arbitrary 3D plasmas. These calculations are vital for understanding, amongst other things, the radio production from axion dark matter conversion in neutron stars, which may lead to indirect axion dark matter detection with current telescopes or future searches, e.g., by the SKA. In this paper, we derive the relevant transport equations in magnetised plasmas. These equations describe both the production and propagation of photons in an arbitrary 3D medium due to the resonant conversion of axions into photons. They also fully incorporate the refraction of photons, and we find no evidence for a conjectured phenomenon of de-phasing. Our result is free of divergences which plagued previous calculations, and our kinetic theory description provides a direct link between ray tracing and the production mechanism. These results mark an important step toward solving one of the major open questions concerning indirect searches of axions in recent years, namely how to compute the photon production rate from axions in arbitrary 3D plasmas.Comment: 45 Pages, 5 figures. Comments welcom

    The penetration of EC markets by UK manufacturing industry.

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    Corporate social performance and the psychological contract

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    This study investigates the role of corporate social performance (CSP) within the psychological contract to better illuminate the micro-processes through which CSP promotes improved firm–stakeholder relationships. It extends the study of psychological contract breach beyond the dyadic relationship between the organization and the employee through an analysis of the impact of employee perceptions of internal and external CSP on psychological contract breach. In so doing, we add significantly to the growing evidence base in relation to if, how, and when affective commitment is enhanced by CSP by explicitly accounting for the role of employee expectations in respect of their employers’ socially responsible initiatives in shaping employees’ attitudinal outcomes.25 page(s

    Development and evaluation of a diagnostic cytokine-release assay for Mycobacterium suricattae infection in meerkats (Suricata suricatta)

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    CITATION: Clarke, C., et al. 2017. Development and evaluation of a diagnostic cytokine-release assay for mycobacterium suricattae infection in meerkats (Suricata suricatta). BMC Veterinary Research, 13:2, doi:10.1186/s12917-016-0927-x.The original publication is available at http://bmcvetres.biomedcentral.comBackground: Sensitive diagnostic tools are necessary for the detection of Mycobacterium suricattae infection in meerkats (Suricata suricatta) in order to more clearly understand the epidemiology of tuberculosis and the ecological consequences of the disease in this species. We therefore aimed to develop a cytokine release assay to measure antigen-specific cell-mediated immune responses of meerkats. Results: Enzyme-linked immunosorbent assays (ELISAs) were evaluated for the detection of interferon-gamma (IFN-γ) and IFN-γ inducible protein 10 (IP-10) in meerkat plasma. An IP-10 ELISA was selected to measure the release of this cytokine in whole blood in response to Bovigam® PC-HP Stimulating Antigen, a commercial peptide pool of M. bovis antigens. Using this protocol, captive meerkats with no known M. suricattae exposure (n = 10) were tested and results were used to define a diagnostic cut off value (mean plus 2 standard deviations). This IP-10 release assay (IPRA) was then evaluated in free-living meerkats with known M. suricattae exposure, categorized as having either a low, moderate or high risk of infection with this pathogen. In each category, respectively, 24.7%, 27.3% and 82.4% of animals tested IPRA-positive. The odds of an animal testing positive was 14.0 times greater for animals with a high risk of M. suricattae infection compared to animals with a low risk. Conclusion: These results support the use of this assay as a measure of M. suricattae exposure in meerkat populations. Ongoing longitudinal studies aim to evaluate the value of the IPRA as a diagnostic test of M. suricattae infection in individual animals.http://bmcvetres.biomedcentral.com/articles/10.1186/s12917-016-0927-xPublisher's versio

    Human biomonitoring research at De Montfort University: school and university participants' recruitment experience

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    Involving teachers in scientific research can increase schoolchildren’s interest in studying science from an early stage which is critical to increase the numbers of high-school students studying scientific subjects. This will impact on the number of students enrolled in university science degrees to satisfy many basic human needs. A group of academics at De Montfort University (DMU, UK) have involved the Ravenhurst Primary School (RPS) in biomedical research, specifically a human biomonitoring (HBM) study involving schoolchildren (aged 6-9 years) and university students (aged 18-22 years) in Leicester (UK) to determine their nutritional status and exposure to metals. We have adopted a school-based approach to recruit participants from both educational arenas following the recommendations for executing HBM studies in Europe [1] with some modifications. Permission from the school authorities was requested after gaining ethical approval from the DMU Research Ethics Committee (Ref. 1674). Parental/student consent was obtained by invitation and appointment letter, with the project details and ethical and data protection aspects written in simple language. Appropriately developed flyers, posters and information leaflets for each audience were also used to enhance the recruitment processes. Scheduling and facilitating flexible face-to-face appointments was critical for collecting the human samples needed for the project (urine and scalp hair) as well as comprehensive details about participants’ diet and anthropometric measurements. The involvement of teachers and lecturers in conjunction with a registered general nurse (school nursing) was of paramount importance for achieving these goals, as they were encouraging participation throughout the process. During the appointments, parents and participants were debriefed in more detail about the project and the relevance of performing HBM to improve health in the community. The school-based approach achieved the following results: a) the recruitment of a relevant number of participants (12 schoolchildren and 111 university students); b) the provision of a satisfying educational experience for parents, teachers/academics and participants in both educational arenas; c) the involvement of school-children in scientific research; d) the acquisition of awareness of the impact of environmental contamination by metals on human health; e) informing participants about their diets and body composition (e.g. percentage of body fat) promoting the necessity of adopting a healthy diet and lifestyle. In conclusion, the project was successful in involving School teachers, University lecturers, schoolchildren, University students and community health workers in a research project. It provided an opportunity for educational development, promote staff motivation and students’ interest and involvement in scientific research. Teachers updated their biomedical knowledge and skills by participating in this research and learnt new methods to engage schoolchildren (by promoting healthy lifestyles, protect the environment, etc.). This could help increase students’ interest in studying science subjects at University and motivate them to embark on a future scientific career. Finally, the UK education system should do more to engage schools and teachers in performing scientific research and thereby make the scientific curriculum more practical that will facilitate students’ learning and engagement

    Evaluating case studies of community-oriented integrated care.

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    This paper summarises a ten-year conversation within London Journal of Primary Care about the nature of community-oriented integrated care (COIC) and how to develop and evaluate it. COIC means integration of efforts for combined disease-treatment and health-enhancement at local, community level. COIC is similar to the World Health Organisation concept of a Community-Based Coordinating Hub - both require a local geographic area where different organisations align their activities for whole system integration and develop local communities for health. COIC is a necessary part of an integrated system for health and care because it enables multiple insights into 'wicked problems', and multiple services to integrate their activities for people with complex conditions, at the same time helping everyone to collaborate for the health of the local population. The conversation concludes seven aspects of COIC that warrant further attention

    Working directly with probabilities in quantum field theory

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    We present a novel approach to computing transition probabilities in quantum field theory, which allows them to be written directly in terms of expectation values of nested commutators and anti-commutators of field operators, rather than squared matrix elements. We show that this leads to a diagrammatic expansion in which the retarded propagator plays a dominant role. As a result, one is able to see clearly how faster-than-light signalling is prevented between sources and detectors. Finally, we comment on potential implications of this approach for dealing with infra-red divergences
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