208 research outputs found

    One dimensional chain of quantum molecule motors as a mathematical physics model for muscle fibre

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    A quantum chain model of many molecule motors is proposed as a mathematical physics theory on the microscopic modeling of classical force-velocity relation and tension transients of muscle fibre. We proposed quantum many-particle Hamiltonian to predict the force-velocity relation for the slow release of muscle fibre which has no empirical relation yet, it is much more complicate than hyperbolic relation. Using the same Hamiltonian, we predicted the mathematical force-velocity relation when the muscle is stimulated by alternative electric current. The discrepancy between input electric frequency and the muscle oscillation frequency has a physical understanding by Doppler effect in this quantum chain model. Further more, we apply quantum physics phenomena to explore the tension time course of cardiac muscle and insect flight muscle. Most of the experimental tension transients curves found their correspondence in the theoretical output of quantum two-level and three-level model. Mathematically modeling electric stimulus as photons exciting a quantum three-level particle reproduced most tension transient curves of water bug Lethocerus Maximus.Comment: 16 pages, 12 figures, Arguments are adde

    A system for rating the stability and strength of medical evidence

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    BACKGROUND: Methods for describing one's confidence in the available evidence are useful for end-users of evidence reviews. Analysts inevitably make judgments about the quality, quantity consistency, robustness, and magnitude of effects observed in the studies identified. The subjectivity of these judgments in several areas underscores the need for transparency in judgments. DISCUSSION: This paper introduces a new system for rating medical evidence. The system requires explicit judgments and provides explicit rules for balancing these judgments. Unlike other systems for rating the strength of evidence, our system draws a distinction between two types of conclusions: quantitative and qualitative. A quantitative conclusion addresses the question, "How well does it work?", whereas a qualitative conclusion addresses the question, "Does it work?" In our system, quantitative conclusions are tied to stability ratings, and qualitative conclusions are tied to strength ratings. Our system emphasizes extensive a priori criteria for judgments to reduce the potential for bias. Further, the system makes explicit the impact of heterogeneity testing, meta-analysis, and sensitivity analyses on evidence ratings. This article provides details of our system, including graphical depictions of how the numerous judgments that an analyst makes can be combined. We also describe two worked examples of how the system can be applied to both interventional and diagnostic technologies. SUMMARY: Although explicit judgments and formal combination rules are two important steps on the path to a comprehensive system for rating medical evidence, many additional steps must also be taken. Foremost among these are the distinction between quantitative and qualitative conclusions, an extensive set of a priori criteria for making judgments, and the direct impact of analytic results on evidence ratings. These attributes form the basis for a logically consistent system that can improve the usefulness of evidence reviews

    Improving access to large-scale digital libraries through semantic-enhanced search and disambiguation

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    With 13,000,000 volumes comprising 4.5 billion pages of text, it is currently very difficult for scholars to locate relevant sets of documents that are useful in their research from the HathiTrust Digital Libary (HTDL) using traditional lexically-based retrieval techniques. Existing document search tools and document clustering approaches use purely lexical analysis, which cannot address the inherent ambiguity of natural language. A semantic search approach offers the potential to overcome the shortcoming of lexical search, but even if an appropriate network of ontologies could be decided upon it would require a full semantic markup of each document. In this paper, we present a conceptual design and report on the initial implementation of a new framework that affords the benefits of semantic search while minimizing the problems associated with applying existing semantic analysis at scale. Our approach avoids the need for complete semantic document markup using pre-existing ontologies by developing an automatically generated Concept-in-Context (CiC) network seeded by a priori analysis of Wikipedia texts and identification of semantic metadata. Our Capisco system analyzes documents by the semantics and context of their content. The disambiguation of search queries is done interactively, to fully utilize the domain knowledge of the scholar. Our method achieves a form of semantic-enhanced search that simultaneously exploits the proven scale benefits provided by lexical indexing

    Exploring the contribution of alternative food networks to food security. A comparative analysis

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    [EN] Food (in)security has become a challenge not only for developing economies but also for High Income Countries. In parallel, food scholars have actively investigated the contribution of alternative food networks (AFNs) to the development of more sustainable and just food systems, paying attention to drivers, initiatives and policies supporting the development of alternatives to the dominant industrialised food system and its detrimental environmental and socio-economic impacts. However, few studies have directly addressed the contribution of AFNs to food security in the Global North. This paper aims to establish new linkages between food security debates and critical AFNs literature. For that purpose, we conduct a place-based approach to food security in a comparative analysis of initiatives of three different European contexts: Cardiff city-region (UK), the Flemish Region (Belgium) and the peri-urban area of the city of Valencia (Spain). The results unfold: i) how AFNs weave a more localised socio-economic fabric that creates new relationships between food security outcomes and specific territories, ii) hybridization processes within alternative but also conventional systems and iii) the role of advocacy and collective action at different levels. The analysis allows identification of key elements on which food security debates hinge and provides new insights to ground conceptual discussions on territorial and place-based food security approaches.This research is part of the project "Assessment of the impact of global drivers of change on Europe's food security" (TRANSMANGO), granted by the EU under 7th Framework Programme; theme KBBE.2013.2.5-01; Grant agreement no: 613532. Dr. Ana Moragues-Faus also acknowledges the funding of the European Commission and the Welsh Government that currently supports her Ser Cymru fellowship. These results reflect only the authors' view; the funders are not liable for any use that may be made of the information contained therein.Cerrada-Serra, P.; Moragues-Faus, A.; Zwart, TA.; Adlerova, B.; Ortiz-Miranda, D.; Avermaete, T. (2018). Exploring the contribution of alternative food networks to food security. A comparative analysis. Food Security. 10(6):1371-1388. https://doi.org/10.1007/s12571-018-0860-xS13711388106Arcuri, S., Brunori, G., & Galli, F. (2017). Insights on the role of private and public actors in food assistance provision: A literature review for high income countries. Economia agro-alimentare. https://doi.org/10.3280/ECAG2017-001006 .Barca, F., McCann, P., & Rodríguez-Pose, A. (2012). The case for regional development intervetion: Place-based versus place-neutral approaches. Journal of Regional Science, 52, 134–152. https://doi.org/10.1111/j.1467-9787.2011.00756.x .Bauler, T., Mutombo, E., van Gameren, V., Crivits, M., Paredis, E., Boulanger, P., . . . Ruwet, C., (2011). Construction of scenarios and exploration of transition pathways for sustainable consumption patterns. Brussels: Belgian Science Policy.Brown, J. C., & Purcell, M. (2005). There’s nothing inherent about scale: Political ecology, the local trap, and the politics of development in the Brazilian Amazon. Geoforum, 36, 607–624. https://doi.org/10.1016/j.geoforum.2004.09.001 .Bourne, N. (2012) Fruit and vegetable community co-ops rise to 350 in Wales, BBC Wales News, Available at http://www.bbc.co.uk/news/uk-wales-17938418 . Accessed Sept 2017.Brunori, G., Malandrin, V., & Rossi, A. (2013). Trade-off or convergence? The role of food security in the evolution of food discourse in Italy. Journal of Rural Studies, 29, 19–29. https://doi.org/10.1016/j.jrurstud.2012.01.013 .Cistulli, V., Rodríguez-Pose, A., Escobar, G., Marta, S., & Schejtman, A. (2014). Addressing food security and nutrition by means of a territorial approach. Food Security, 6, 879–894. https://doi.org/10.1007/s12571-014-0395-8 .Clay, E. (2002). Food security; concept and measurement. Paper for FAO expert consultation on trade and food security: Conceptualising the linkages. Rome http://www.fao.org/docrep/005/y4671e/y4671e06.htm . Accessed Sept 2017.Cox, I. (2015). Interim report: Adding value and demonstrating sustainable development in the community food co-ops in Wales, EcoStudio.Crivits, M., & Paredis, E. (2013). Designing an explanatory practice framework: Local food systems as a case. Journal of Consumer Culture, 13, 306–336. https://doi.org/10.1177/1469540513484321joc.sagepub.com .CSM (2016). Connecting small-holders to farmers: an analytical guide.Dedeurwaedere, T., de Schutter, O., Hudon, M., Mathijs, E., Annaert, B., Avermaete, T., et al. (2015). Working paper: Social enterprise based transition movements between transformation and reform. The case of transition initiatives in local food networks. BRAIN-be. Food4Sustainability annual report 2. Deliverable 2.2.Dixon, J., & Richards, C. (2016). On food security and alternative food networks: Understanding and performing food security in the context of urban bias. Agriculture and Human Values, 33, 191–202. https://doi.org/10.1007/s10460-015-9630-y .Ekers, M., Levkoe, C. Z., Walker, S., & Dale, B. (2015). Will work for food: Agricultural interns, apprentices, volunteers, and the agrarian question. Agriculture and Human Values, 33, 705–720. https://doi.org/10.1007/s10460-015-9660-5 .Elliott, E., Parry, O., Ashdown-Lambert, J. (2004). Evaluation of community food co-ops, Working Paper 85, Cardiff School of Social Sciences, Cardiff University.FAO (1998). Report: Sustaining agricultural biodiversity and agro-ecosystem functions. http://www.fao.org/sd/EPdirect/EPre0080.htm . Accessed Nov 2017.FAO (2001). Report: The state of food insecurity in the world. http://www.fao.org/docrep/003/y1500e/y1500e00.htm . Accessed Nov 2017.Gibson-Graham, J. K. (2006). A postcapitalist politics. Minessota: University of Minnesota Press.Goodman, M. K. (2004). Reading fair trade: Political ecological imaginary and the moral economy of fair trade foods. Political Geography, 23, 891–915. https://doi.org/10.1016/j.polgeo.2004.05.013 .Goodman, D., DuPuis, E.M., Goodman, M.K. (2012). Alternative food networks: Knowledge, place and politics. Routledge, Oxon, New York. ISBN: 9780203804520.Goodman, D., DuPuis, E. M., & Goodman, M. K. (2013). Engaging alternative food networks: Commentaries and research agendas. International Journal of Sociology of Agriculture and Food, 20, 425–431.Guinot, E. (2008) El paisaje de la Huerta de Valencia. Elementos de interpretación de su morfología espacial de origen medieval. Historia de la Ciudad V. Tradición y progreso, 98–111. Valencia: Icaro-Colegio Territorial de Arquitectos de Valencia-Universidad Politécnica de Valencia.Guthman, J. (2004). Agrarian dreams: The paradox of organic farming in California. University of California Press, Berkeley. ISBN-10: 0520240952.Hubeau, M., Coteur, I., Mondelaers, K., & Marchand, F. (2015). Systeembeschrijving van het Vlaamse Landbouw- en Voedingssysteem: een nulmeting. Merelbeke, Belgie: ILVO.Ilbery, B., & Maye, D. (2005). Alternative (shorter) food supply chains and specialist livestock products in the Scottish - English borders. Environment and Planning, 37, 823–844. https://doi.org/10.1068/a3717 .IPCC (2012). Glossary of terms. In C. B. Field, V. Barros, T. F. Stocker, D. Qin, D. J. Dokken, K. L. Ebi et al. (Eds.), Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change (IPCC), (pp. 555–564). Cambridge: Cambridge University Press.Jarosz, L. (2007). The city in the country: Growing alternative food networks in metropolitan areas. Journal of Rural Studies, 24, 231–244. https://doi.org/10.1016/j.jrurstud.2007.10.002 .Jones, I. (2012). Evaluation of the community food co-operative programme in Wales, BMG research, Welsh Government social research, 22/2012.Kirwan, J., & Maye, D. (2013). Food security framings within the UK and the integration of local food systems. Journal of Rural Studies, 29, 91–100. https://doi.org/10.1016/j.jrurstud.2012.03.002 .Lamine, C. (2015). Sustainability and resilience in Agrifood systems: Reconnecting agriculture, food and the environment. Sociologia Ruralis, 55, 41–61. https://doi.org/10.1111/soru.12061 .Loopstra, R., Reeves, A., McKee, M., & Stuckler, D. (2016). Food insecurity and social protection in Europe: Quasi-natural experiment of Europe’s great recessions 2004–2012. Preventive Medicine, 89, 44–50. https://doi.org/10.1016/j.ypmed.2016.05.010 .MacMillan, T., & Dowler, E. (2012). Just and sustainable? Examining the rhetoric and potential realities of UK food security. Journal of Agricultural and Environmental Ethics, 25, 181–204. https://doi.org/10.1007/s10806-011-9304-8 .Marsden, T., Banks, J., Bristow, G. (2000). Food supply chain approaches: exploring their role in rural development. Sociologia Ruralis, https://doi.org/10.1111/1467-9523.00158Maxwell, S. (1996). Food security: A post-modern perspective. Food Policy, 21, 155–170. https://doi.org/10.1016/0306-9192(95)00074-7 .Mooney, P.H., Hunt, S.A. (2009). Food security: The elaboration of contested claims to a consensus frame. Sociologia Ruralis. https://doi.org/10.1111/j.1549-0831.2009.tb00701.x .Moragues-Faus, A. (2016). Participative action research: Transforming Cardiff’s food system through students’ live projects. Report available at http://foodcardiff.com/wp-content/uploads/2016/10/Report-live-projects-2016-cut-.pdf. . Accessed Sept 2017.Moragues-Faus, A. (2017a). Emancipatory or neoliberal food politics? Exploring the “politics of collectivity” of buying groups in the search for egalitarian food democracies. Antipode, 49, 455–476. https://doi.org/10.1111/anti.12274 .Moragues-Faus, A. (2017b). Problematising justice definitions in public food security debates: Towards global and participative food justices. Geoforum, 84, 95–106. https://doi.org/10.1016/j.geoforum.2017.06.007 .Moragues-Faus, A., & Marsden, T. (2017). The political ecology of food: Carving “spaces of possibility” in a new research agenda. Journal of Rural Studies, 55, 275–288. https://doi.org/10.1016/j.jrurstud.2017.08.016 .Moragues-Faus, A., Sonnino, R., 2012. Embedding quality in the agro-food system: The dynamics and implications of place-making strategies in the olive oil sector of alto Palancia, Spain. Sociologia Ruralis, https://doi.org/10.1111/j.1467-9523.2011.00558.x .Morgan, K., & Sonnino, R. (2010). The urban foodscape: World cities and the new food equation. Cambridge Journal of Regions, Economy and Society, 3, 209–224. https://doi.org/10.1093/cjres/rsq007 .Murdoch, J., & Miele, M. (1999). “Back to nature”: Changing “worlds of production” in the food sector. Sociologia Ruralis, 39, 465–483. https://doi.org/10.1111/1467-9523.00119 .Murdoch, J., Marsden, T., & Banks, J. (2000). Quality, nature, and embeddedness: Some theoretical considerations in the context of the food sector. Economic Geography, 76, 107–125. https://doi.org/10.1111/j.1944-8287.2000.tb00136.x .OECD, FAO, UNCDF (2016). Adopting a territorial approach to food security and nutrition policy. Paris. https://doi.org/10.1787/9789264257108-en .Ortiz-Miranda, D., Moragues-Faus, A.M., 2014. Governing fair trade coffee supply: dynamics and challenges in small farmers’ organizations. Sustainable Development, https://doi.org/10.1002/sd.1570 .Oxfam and Church Action. (2013). Walking the breadline: The scandal of food poverty in 21st-century Britain. http://policy-practice.oxfam.org.uk/publications/walking-the-breadline-the-scandal-of-food-poverty-in-21st-century-britain-292978 . Accessed 19 August 2014.Padel, S., & Foster, C. (2005). Exploring the gap between attitudes and behaviour: Understandingwhy consumers buy or do not buy organic food. British Food Journal, 107, 606–625. https://doi.org/10.1108/00070700510611002 .Radhika Ch., Hemantha U., 2017. Research study on nutrition security and equity in its access in watershed development programmes. Research reports series 107. National Institute of Rural Development & Panchayati Raj. ISBN 978-93-84503-81-9.Renting, H., Marsden, T. K., & Banks, J. (2003). Understanding alternative food networks: Exploring the role of short food supply chains in rural development. Environment and Planning, 35, 393–411. https://doi.org/10.1068/a3510 .Renting, H., Schermer, M., & Rossi, A. (2012). Building food democracy: Exploring civic food networks and newly emerging forms of food citizenship. International Journal of Sociology of Agriculture and Food, 19, 289–307.Romero, J., & Francés, M. (Eds.). (2012). La Huerta de Valencia. Un paisaje cultural con futuro incierto. Valencia: Publicaciones de la Universitat de València.Sage, C. (2003). Social embeddedness and relations of regard: Alternative “good food” networks in south-West Ireland. Journal of Rural Studies, 19, 47–60. https://doi.org/10.1016/S0743-0167(02)00044-X .Sonnino, R., & Marsden, T. (2006). Beyond the divide: Rethinking relationships between alternative and conventional food networks in Europe. Journal of Economic Geography, 6, 181–199. https://doi.org/10.1093/jeg/lbi006 .Sonnino, R., Marsden, T., & Moragues-Faus, A. (2016). Relationalities and convergences in food security narratives: Towards a place-based approach. Transactions of the Institute of British Geographers, 41, 477–489. https://doi.org/10.1111/tran.12137 .Soriano i Piqueras, V. (2015). La huerta de Valencia un paisaje menguante. Amazon. ISBN-13: 978-1512009231.Stanners, D., & Bourdeau, P. (1995). Europe’s environment: The Dobris assessment. Copenhagen: European Environmental Agency.Tregear, A. (2011). Progressing knowledge in alternative and local food networks: Critical reflections and a research agenda. Journal of Rural Studies, 27, 419–430. https://doi.org/10.1016/j.jrurstud.2011.06.003 .Valencia City Council. (2016). Department of Agricultura and Huerta (ongoing review). Pla d’Acció Integral per a la promoció de l’activitat i el territori agrícola municipal. https://hortaipoblesvalencia.org/es/agricultura-y-huerta/ . Accessed Jan 2018.Van Gameren, V., Ruwet, C., & Bauler, T. (2015). Towards a governance of sustainable consumption transitions: How institutional factors influence emerging local food systems in Belgium. Local Environment: The international journal of justice and sustainability, https://doi.org/10.1080/13549839.2013.872090 .Venn, L., Kneafsey, M., Holloway, L., Cox, R., Dowler, E., & Tuomainen, H. (2006). Researching European “alternative” food networks: Some methodological considerations. Area, 38, 248–258. https://doi.org/10.1111/j.1475-4762.2006.00694.x .Vervoort, J., Thornton, P. K., Kristjanson, P., et al. (2014). Challenges to scenario-guided adaptive action on food security under climate change. Global Environmental Change, 28, 383–394. https://doi.org/10.1016/j.gloenvcha.2014.03.001 .Weingartner L. (2005). Paper I. The concept of food and nutrition security. In: Klennert K, editor. Achieving food and nutrition security: Actions to meet the global challenge: A training course reader. Feldafing: German Society for International Cooperation; p. 3–28. ISBN 3-937235 -71-X.Whatmore, S., Stassart, P., & Renting, H. (2003). What’s alternative about alternative food networks? Environment and Planning, 35, 389–391. https://doi.org/10.1068/a3621 .Zwart, T. A., Mathijs, E., Avermaete, T. (2016). Can alternative food networks contribute to a transition towards sustainability in Flanders: Assessing the marketing functions of Voedselteams. Report available at http://ageconsearch.umn.edu/record/245069/files/BioeconWP_2016_04_submitted.pdf . Accessed Sept 2017

    Mechanical properties of the compass depressors of the sea-urchin Paracentrotus lividus (Echinodermata, Echinoidea) and the effects of enzymes, neurotransmitters and synthetic tensilin-like protein

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    The compass depressors (CDs) of the sea-urchin lantern are ligaments consisting mainly of discontinuous collagen fibrils associated with a small population of myocytes. They are mutable collagenous structures, which can change their mechanical properties rapidly and reversibly under nervous control. The aims of this investigation were to characterise the baseline (i.e. unmanipulated) static mechanical properties of the CDs of Paracentrotus lividus by means of creep tests and incremental force-extension tests, and to determine the effects on their mechanical behaviour of a range of agents. Under constant load the CDs exhibited a three-phase creep curve, the mean coefficient of viscosity being 561±365 MPa.s. The stress-strain curve showed toe, linear and yield regions; the mean strain at the toe-linear inflection was 0.86±0.61; the mean Young's modulus was 18.62±10.30 MPa; and the mean tensile strength was 8.14±5.73 MPa. Hyaluronidase from Streptomyces hyalurolyticus had no effect on creep behaviour, whilst chondroitinase ABC prolonged primary creep but had no effect on secondary creep or on any force-extension parameters; it thus appears that neither hyaluronic acid nor sulphated glycosaminoglycans have an interfibrillar load transfer function in the CD. Acetylcholine, the muscarinic agonists arecoline and methacholine, and the nicotinic agonists nicotine and 1-[1-(3,4-dimethyl-phenyl)-ethyl]-piperazine produced an abrupt increase in CD viscosity; the CDs were not differentially sensitive to muscarinic or nicotinic agonists. CDs showed either no, or no consistent, response to adrenaline, L-glutamic acid, 5-hydroxytryptamine and γ-aminobutyric acid. Synthetic echinoid tensilin-like protein had a weak and inconsistent stiffening effect, indicating that, in contrast to holothurian tensilins, the echinoid molecule may not be involved in the regulation of collagenous tissue tensility. We compare in detail the mechanical behaviour of the CD with that of mammalian tendon and highlight its potential as a model system for investigating poorly understood aspects of the ontogeny and phylogeny of vertebrate collagenous tissues.(undefined)info:eu-repo/semantics/publishedVersio

    Constitutive modelling of skin ageing

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    The objective of this chapter is to review the main biomechanical and structural aspects associated with both intrinsic and extrinsic skin ageing, and to present potential research avenues to account for these effects in mathematical and computational models of the skin. This will be illustrated through recent work of the authors which provides a basis to those interested in developing mechanistic constitutive models capturing the mechanobiology of skin across the life course
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