14,216 research outputs found

    Hawking-like emission in kink-soliton escape from a potential well.

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    The escape of solitons over a potential barrier is analysed within the framework of a nonlinear Klein–Gordon equation. It is shown that the creation of a kink–antikink pair near the barrier through an internal mode instability can be followed by escape of the kink in a process analogous to Hawking radiation. These results have important implications in a wider context, including stochastic resonance and ratchet systems, which are also discussed

    XMM-Newton and Deep Optical Observations of the OTELO fields: the Groth-Westphal Strip

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    OTELO (OSIRIS Tunable Emission Line Object Survey) will be carried out with the OSIRIS instrument at the 10 m GTC telescope at La Palma, and is aimed to be the deepest and richest survey of emission line objects to date. The deep narrow-band optical data from OSIRIS will be complemented by means of additional observations that include: (i) an exploratory broad-band survey that is already being carried out in the optical domain, (ii) FIR and sub-mm observations to be carried with the Herschel space telescope and the GTM, and (iii) deep X-Ray observations from XMM-Newton and Chandra.Here we present a preliminary analysis of public EPIC data of one of the OTELO targets,the Groth-Westphal strip, gathered from the XMM-Newton Science Archive (XSA). EPIC images are combined with optical BVRI data from our broadband survey carried out with the 4.2m WHT at La Palma. Distance-independent diagnostics (involving X/O ratio, hardness ratios, B/T ratio) are tested.Comment: 2 pages, 2 figures, uses graphicx package. To appear in proceedings of "The X-Ray Universe 2005", San Lorenzo del Escorial, Spain, September 26-30, 200

    A class of Hamilton-Jacobi equations on Banach-Finsler manifolds

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    The concept of subdifferentiability is studied in the context of C1C^1 Finsler manifolds (modeled on a Banach space with a Lipschitz C1C^1 bump function). A class of Hamilton-Jacobi equations defined on C1C^1 Finsler manifolds is studied and several results related to the existence and uniqueness of viscosity solutions are obtained.Comment: 24 page

    Environmental and social consequences of the increase in the demand for superfoods world-wide

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    1.The search for healthy diets has led to a surge in the demand for functional foods or ‘superfoods’, which have now become popular among the middle- and high- income fractions of the society in developed regions of the world. ‘Superfoods’ are predominantly consumed far from their centres of origin and out of their cul- tural context with different environmental and social effects. 2. Here, we present a series of case studies to provide an overview of the different environmental impacts driven by superfood expansion. 3. We show that if these crops are to follow the path of other global commodities, then strong environmental impacts and large carbon footprints are expected in terms of land clearing, use of agrochemicals and transportation during times of high prices (boom) and social problems as farmers have to abandon their liveli- hoods when prices sink below the cost of production (bust). 4. We also showcase how a combination of management practices, consumer choices and policy changes could help in alleviating the ecological footprint of these crops.Both A.M. and M.J.S. are funded through Ikerbasque, the Basque Foundation for Science. Research was also supported by the Spanish State Research Agency through María de Maeztu Excellence Unit accreditation (MDM‐2017‐0714) and the Basque Government BERC Programme

    Discrete events simulation method for analyze cycle time: a case study in the plastics industry sector

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    This work shows the potential of the Discrete-Event Simulation -DES- in a software modeling process applied to business decision making, using a descriptive methodology in a productive process of a manufacturing plastic bags company. The analysis identified the process characteristics and built a simulated model in Arena® software. Simulation shown variability in the process greater than 50% in the cycle time, which negatively affects the economic interests of the company, impacting opportunities to supply the market risking its position with other companies in the sector. The method implemented in the present work allows to know the critical points of the process, evaluate them and project a path to obtain the optimal or most viable solution, and propose modifications rising up the probability of success of any improvement plan. This makes any economic investment or locative change a desition-making quantitative supported
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