92 research outputs found

    A cellular automata for e-planning sustainable urban forms

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    A cellular automata-like model, twinned with interactive intelligent geographical systems, is presented to drive planning process toward sustainable urban forms. The use of algorithms and mathematical approaches for the study of urban forms [1] becomes increasingly useful and sometimes indispensable for the understanding of social, economics, behavioural and spatial urban phenomena, and, when possible, for their guidance toward objectively desired patterns. A vast literature using cellular automata for urban growth processes [2] succeeded earlier cellular automata models of three decades ago [3]. Urban morphogenesis is a critical theme due to the exceptional magnitude and speed of world urbanisation which urge novel models of cities if we want a pleasant life and sustainable growth [4]. Isobenefit Urbanism [4] is a libertarian paternalistic approach whose morphogenetic code induces a particular green/built spatiality and a 15-minute walking city where one can reach within 1km natural land, shops, amenities, services and places of work. It does so by leaving free the actual urban development and growth to follow spontaneous random – or locally desired – patterns of functional locations and density across the urban planimetry liberally driven by market forces and genius loci. The outputs are in fact infinites, though all satisfying the code design objective function which can generate interesting urban environmental, planning and economic impacts [5]

    Geometrical control of pure spin current induced domain wall depinning

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    [EN] We investigate the pure spin-current assisted depinning of magnetic domain walls in half ring based Py/Al lateral spin valve structures. Our optimized geometry incorporating a patterned notch in the detector electrode, directly below the Al spin conduit, provides a tailored pinning potential for a transverse domain wall and allows for a precise control over the magnetization configuration and as a result the domain wall pinning. Due to the patterned notch, we are able to study the depinning field as a function of the applied external field for certain applied current densities and observe a clear asymmetry for the two opposite field directions. Micromagnetic simulations show that this can be explained by the asymmetry of the pinning potential. By direct comparison of the calculated efficiencies for different external field and spin current directions, we are able to disentangle the different contributions from the spin transfer torque, Joule heating and the Oersted field. The observed high efficiency of the pure spin current induced spin transfer torque allows for a complete depinning of the domain wall at zero external field for a charge current density of 6 1011 A m−2, which is attributed to the optimal control of the position of the domain wall.Comisión Europea (P7-PEOPLE-2013-ITN 608031, FP7-ICT-2009-5) Gobierno de España (MAT2014-52477-C5-4-P) Junta de Castilla y Leon (SA090U16) German Ministry for Education and Science (BMBF) German Research Foundation (DFG) via the DFG collaborative research centre SFB/TRR 173 SPIN+X Graduate School Material Science in Mainz (DFG/GSC 266) European Research Council - MultiRev (665672) Research Center of Innovative and Emerging Materials at Johannes Gutenberg University (CINEMA) German Academic Exchange Service (DAAD) via the SpinNet Program 56268455 French RENATECH networ

    Wire edge dependent magnetic domain wall creep

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    open13While edge pinning is known to play an important role in sub-μm wires, we demonstrate that strong deviations from the universal creep law can occur in 1 to 20 μm wide wires. Magnetic imaging shows that edge pinning translates into a marked bending of domain walls at low drive and is found to depend on the wire fabrication process and aging. Edge pinning introduces a reduction of domain wall velocity with respect to full films which increasingly dominates the creep dynamics as the wire width decreases. We show that the deviations from the creep law can be described by a simple model including a counter magnetic field which links the width of the wire to the edge dependent pinning strength. This counter field defines a key nonuniversal contribution to creep motion in patterned structures.openHerrera Diez, L.; Jeudy, V.; Durin, G.; Casiraghi, A.; Liu, Y. T.; Voto, M.; Agnus, G.; Bouville, D.; Vila, L.; Langer, J.; Ocker, B.; Lopez-Diaz, L.; Ravelosona, D.Herrera Diez, L.; Jeudy, V.; Durin, G.; Casiraghi, A.; Liu, Y. T.; Voto, M.; Agnus, G.; Bouville, D.; Vila, L.; Langer, J.; Ocker, B.; Lopez-Diaz, L.; Ravelosona, D

    Butyrate as bioactive human milk protective component against food allergy

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    Background: Food allergy (FA) is a growing health problem worldwide. Effective strategies are advocated to limit the disease burden. Human milk (HM) could be considered as a protective factor against FA, but its mechanisms remain unclear. Butyrate is a gut microbiota-derived metabolite able to exert several immunomodulatory functions. We aimed to define the butyrate concentration in HM, and to see whether the butyrate concentration detected in HM is able to modulate the mechanisms of immune tolerance. Methods: HM butyrate concentration from 109 healthy women was assessed by GS-MS. The effect of HM butyrate on tolerogenic mechanisms was assessed in in vivo and in vitro models. Results: The median butyrate concentration in mature HM was 0.75 mM. This butyrate concentration was responsible for the maximum modulatory effects observed in all experimental models evaluated in this study. Data from mouse model show that in basal condition, butyrate up-regulated the expression of several biomarkers of gut barrier integrity, and of tolerogenic cytokines. Pretreatment with butyrate significantly reduced allergic response in three animal models of FA, with a stimulation of tolerogenic cytokines, inhibition of Th2 cytokines production and a modulation of oxidative stress. Data from human cell models show that butyrate stimulated human beta defensin-3, mucus components and tight junctions expression in human enterocytes, and IL-10, IFN-γ and FoxP3 expression through epigenetic mechanisms in PBMCs from FA children. Furthermore, it promoted the precursors of M2 macrophages, DCs and regulatory T cells. Conclusion: The study's findings suggest the importance of butyrate as a pivotal HM compound able to protect against FA
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