2,637 research outputs found

    Fear of large carnivores causes a trophic cascade

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    The fear large carnivores inspire, independent of their direct killing of prey, may itself cause cascading effects down food webs potentially critical for conserving ecosystem function, particularly by affecting large herbivores and mesocarnivores. However, the evidence of this has been repeatedly challenged because it remains experimentally untested. Here we show that experimentally manipulating fear itself in free-living mesocarnivore (raccoon) populations using month-long playbacks of large carnivore vocalizations caused just such cascading effects, reducing mesocarnivore foraging to the benefit of the mesocarnivore\u27s prey, which in turn affected a competitor and prey of the mesocarnivore\u27s prey. We further report that by experimentally restoring the fear of large carnivores in our study system, where most large carnivores have been extirpated, we succeeded in reversing this mesocarnivore\u27s impacts. We suggest that our results reinforce the need to conserve large carnivores given the significant ecosystem service the fear of them provides

    Weight Assessment for Fuselage Shielding on Aircraft With Open-Rotor Engines and Composite Blade Loss

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    The Federal Aviation Administration (FAA) has been engaged in discussions with airframe and engine manufacturers concerning regulations that would apply to new technology fuel efficient "openrotor" engines. Existing regulations for the engines and airframe did not envision features of these engines that include eliminating the fan blade containment systems and including two rows of counter-rotating blades. Damage to the airframe from a failed blade could potentially be catastrophic. Therefore the feasibility of using aircraft fuselage shielding was investigated. In order to establish the feasibility of this shielding, a study was conducted to provide an estimate for the fuselage shielding weight required to provide protection from an open-rotor blade loss. This estimate was generated using a two-step procedure. First, a trajectory analysis was performed to determine the blade orientation and velocity at the point of impact with the fuselage. The trajectory analysis also showed that a blade dispersion angle of 3deg bounded the probable dispersion pattern and so was used for the weight estimate. Next, a finite element impact analysis was performed to determine the required shielding thickness to prevent fuselage penetration. The impact analysis was conducted using an FAA-provided composite blade geometry. The fuselage geometry was based on a medium-sized passenger composite airframe. In the analysis, both the blade and fuselage were assumed to be constructed from a T700S/PR520 triaxially-braided composite architecture. Sufficient test data on T700S/PR520 is available to enable reliable analysis, and also demonstrate its good impact resistance properties. This system was also used in modeling the surrogate blade. The estimated additional weight required for fuselage shielding for a wing- mounted counterrotating open-rotor blade is 236 lb per aircraft. This estimate is based on the shielding material serving the dual use of shielding and fuselage structure. If the shielding material is not used for dual purpose, and is only used for shielding, then the additional weight per aircraft is estimated to be 428 lb. This weight estimate is based upon a number of assumptions that would need to be revised when applying this concept to an actual airplane design. For example, the weight savings that will result when there is no fan blade containment system, manufacturing limitations which may increase the weight where variable thicknesses was assumed, engine placement on the wing versus aft fuselage, etc

    Solar Sail Spaceflight Simulation

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    The Solar Sail Spaceflight Simulation Software (S5) toolkit provides solar-sail designers with an integrated environment for designing optimal solar-sail trajectories, and then studying the attitude dynamics/control, navigation, and trajectory control/correction of sails during realistic mission simulations. Unique features include a high-fidelity solar radiation pressure model suitable for arbitrarily-shaped solar sails, a solar-sail trajectory optimizer, capability to develop solar-sail navigation filter simulations, solar-sail attitude control models, and solar-sail high-fidelity force models

    A metatranscriptomic approach to explore longitudinal tissue specimens from non-healing diabetes related foot ulcers

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    Cellular mechanisms and/or microbiological interactions which contribute to chronic diabetes related foot ulcers (DRFUs) were explored using serially collected tissue specimens from chronic DRFUs and control healthy foot skin. Total RNA was isolated for next-generation sequencing. We found differentially expressed genes (DEGs) and enriched hallmark gene ontology biological processes upregulated in chronic DRFUs which primarily functioned in the host immune response including: (i) Inflammatory response; (ii) TNF signalling via NFKB; (iii) IL6 JAK-STAT3 signalling; (iv) IL2 STAT5 signalling and (v) Reactive oxygen species. A temporal analysis identified RN7SL1 signal recognition protein and IGHG4 immunoglobulin protein coding genes as being the most upregulated genes after the onset of treatment. Testing relative temporal changes between healing and non-healing DRFUs identified progressive upregulation in healed wounds of CXCR5 and MS4A1 (CD20), both canonical markers of lymphocytes (follicular B cells/follicular T helper cells and B cells, respectively). Collectively, our RNA-seq data provides insights into chronic DRFU pathogenesis

    Stroke Induces Prolonged Changes in Lipid Metabolism, the Liver and Body Composition in Mice

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    Acknowledgements We would like to thank the Biological Services Facility at the University of Manchester for expert animal husbandry and Karen Davies who helped with the MRI. The Histology Facility equipment that was used in this study was purchased by the University of Manchester Strategic Fund. Special thanks goes to Peter Walker for their help with the histology. Funding information This work was supported by the Kohn Foundation, an Edward Bonham Carter Doctoral Scholarship, an EPSRC/MRC Centre for Doctoral Training in Regenerative Medicine studentship grant (EP/L014904/1), and the Medical Research Council (MR/K501311/1).Peer reviewedPublisher PD

    Stakeholder perceptions of physical literacy:results from a national consultation in England

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    Background: There is a lack of evidence of stakeholder perspective and understanding of physical literacy among relevant stakeholders from England. As part of research commissioned by Sport England to develop a physical literacy consensus statement for England, this study presents findings from the first national consultation with stakeholders in England.Methods: One hundred and ninety-three individual stakeholders (50.3%) from education, community sport, national governing bodies of sport, physical activity and sport coaching sectors completed an online survey consisting of fixed item and open ended questions designed to examine their knowledge, understanding, perceptions and practices relating to physical literacy. Results: Responses from stakeholders suggested there was confusion in use of the term physical literacy in practice and confusion regarding the definition of physical literacy. Most respondents suggested they were involved in physical literacy related activity and understood the term. However, when probed the physical literacy related activity they referred to was likely not actually physical literacy related. Understanding of the term physical literacy was inconsistent in general. Stakeholders considered the affective, social, physical and cognitive areas (domains) of learning to be most important for developing a positive relationship with movement, sport and physical activity for life. Conclusions: While stakeholders are aware of the term “physical literacy” and hold value of it within their practice, there remain key misconceptions relating to what physical literacy is, and debate as to whether any existing definitions truly capture the construct of physical literacy

    Exploring the dynamics of compliance with community penalties

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    In this paper, we examine how compliance with community penalties has been theorized hitherto and seek to develop a new dynamic model of compliance with community penalties. This new model is developed by exploring some of the interfaces between existing criminological and socio-legal work on compliance. The first part of the paper examines the possible definitions and dimensions of compliance with community supervision. Secondly, we examine existing work on explanations of compliance with community penalties, supplementing this by drawing on recent socio-legal scholarship on private individuals’ compliance with tax regimes. In the third part of the paper, we propose a dynamic model of compliance, based on the integration of these two related analyses. Finally, we consider some of the implications of our model for policy and practice concerning community penalties, suggesting the need to move beyond approaches which, we argue, suffer from compliance myopia; that is, a short-sighted and narrowly focused view of the issues

    Neutron-proton differential cross sections in the range 70 to 400 GeV/c

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    We report the results of an experiment which measured np elastic scattering differential cross sections over a range in -t from 0.15 to ~3.6 (GeV/c)2 for incident neutron momenta from 70 to 400 GeV/c. We find the logarithmic slope parameter, evaluated at -t = 0.2 (GeV/c)2, to be consistent with existing proton-proton parametrizations. The data exhibit a dip in the cross section near -t = 1.4 (GeV/c)2 for incident neutron momenta above 200 GeV/c. For neutron momenta less than 280 GeV/c, the neutron-proton cross sections are found to be higher than existing proton-proton data in the range 0.7 [les] -t [les] 1.3 (GeV/c)2 which is in contradiction to most Regge predictions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23627/1/0000590.pd
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