190,245 research outputs found
Botanical Fabrication: A research project at the intersection of design, botany and horticulture
No full text‘Botanical Fabrication’ is an on-going research initiative which investigates how an understanding of botany and horticultural techniques can challenge the design process and lead to alternative sustainable manufacturing or ‘eco-facturing’ tools. This paper presents different phases of the project, from an initial research workshop (2012), to an exhibition-based experiment (Botanical Factory, 2013) and includes current work in progress (Solar Gourd, 2015) so as to articulate a critical analysis of the work to date. In a context where we urgently need to devise new principles to live, manufacture and consume within the ecological capacity of our finite planet, the paper argues for the development of a new framework for slow manufacturing with plant systems. From Darwin’s research into plant movements to our current understanding of plant physics and biomechanics, designers can begin to integrate botanical and horticultural knowledge to play with the environment of plant growth and envision production chains of a new type
Complexity for extended dynamical systems
No full textWe consider dynamical systems for which the spatial extension plays an important role. For these systems, the notions of attractor, ε-entropy and topological entropy per unit time and volume have been introduced previously. In this paper we use the notion of Kolmogorov complexity to introduce, for extended dynamical systems, a notion of complexity per unit time and volume which plays the same role as the metric entropy for classical dynamical systems. We introduce this notion as an almost sure limit on orbits of the system. Moreover we prove a kind of variational principle for this complexity
On the essential spectrum of the transfer operator for expanding markov maps
No full textThe essential spectrum of the transfer operator for expanding markov maps of the interval is studied in detail. To this end we construct explicitly an infinite set of eigenfunctions which allows us to prove that the essential spectrum in C_k is a disk whose radius is related to the free energy of the Liapunov exponent
The role of disorder in the dynamics of critical fluctuations of mean field models
No full textThe purpose of this paper is to analyze how disorder affects the dynamics of critical
fluctuations for two different types of interacting particle system: the Curie-Weiss
and Kuramoto model. The models under consideration are a collection of spins and
rotators respectively. They both are subject to a mean field interaction and embedded
in a site-dependent, i.i.d. random environment. As the number of particles goes
to infinity their limiting dynamics become deterministic and exhibit phase transition.
The main result concerns the fluctuations around this deterministic limit at the critical
point in the thermodynamic limit. From a qualitative point of view, it indicates
that when disorder is added spin and rotator systems belong to two different classes
of universality, which is not the case for the homogeneous models (i.e., without disorder)
Concentration inequalities for random fields via coupling
No full textWe present a new and simple approach to concentration inequalities in the context of dependent random processes and random fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the coupling, one obtains exponential concentration inequalities. If such a uniform control is no more possible, then one obtains polynomial or stretched-exponential concentration inequalities. Our abstract results apply to Gibbs random fields, both at high and low temperatures and in particular to the low-temperature Ising model which is a concrete example of non-uniformity of the coupling.
Antithrombotic therapy in TAVI patients: changing concepts.
No full textThe clinical and demographic characteristics of patients undergoing TAVI pose unique challenges for developing and implementing optimal antithrombotic therapy. Ischaemic and bleeding events in the periprocedural period and months after TAVI still remain a relevant concern to be faced with optimised antithrombotic therapy. Moreover, the antiplatelet and anticoagulant pharmacopeia has evolved significantly in recent years with new drugs and multiple possible combinations. Dual antiplatelet therapy (DAPT) is currently recommended after TAVI with oral anticoagulation (OAC) restricted for specific indications. However, atrial fibrillation (which is often clinically silent and unrecognised) is common after the procedure and embolic material often thrombin-rich. Recent evidence has therefore questioned this approach, suggesting that DAPT may be futile compared with aspirin alone and that OAC could be a relevant alternative. Future randomised and appropriately powered trials comparing different regimens of antithrombotic therapy, including new antiplatelet and anticoagulant agents, are warranted to increase the available evidence on this topic and create appropriate recommendations for this frail population. Meanwhile, it remains rational to adhere to current guidelines, with routine DAPT and recourse to OAC when specifically indicated, whilst always tailoring therapy on the basis of individual bleeding and thromboembolic risk
Path-space moderate deviation principles for the random field curie-weiss model
No full textWe analyze the dynamics of moderate fluctuations for macroscopic observables of the random field Curie-Weiss model (i.e., standard Curie-Weiss model embedded in a site-dependent, i.i.d. random environment). We obtain path-space moderate deviation principles via a general analytic approach based on convergence of nonlinear generators and uniqueness of viscosity solutions for associated Hamilton-Jacobi equations. The moderate asymptotics depend crucially on the phase we consider and moreover, the space-time scale range for which fluctuations can be proven is restricted by the addition of the disorder.</p
Rigidity of Holomorphic Collet-Eckmann Repellers
No full text. We prove rigidity results for a class of non-uniformly hyperbolic holomorphic maps: If a holomorphic Collet-Eckmann map f is topologically conjugate to a holomorphic map g, then the conjugacy can be improved to be quasiconformal. If there is only one critical point in the repeller, then g is Collet-Eckmann, too. 1. Introduction Collet-Eckmann maps of the interval were introduced by P. Collet and J.-P. Eckmann as a large class of non-uniformly expanding maps for which a probability absolutely continuous invariant measure exists. A theory of rational Collet-Eckmann maps was originated in [P2] and continued in [P3], [GS] and [PR]; see [PR] for a more detailed historical account. This paper is a continuation of [PR]. We consider repellers for holomorphic maps, without assuming the maps extend to rational maps. Consider a compact set X in the Riemann sphere C , together with a holomorphic map f : U ! C with f(X) = X, where U is a neighbourhood of X. We call the pair (X; f) a holomorp..
André Collet. Histoire de l'armement depuis 1945
No full textGrand. André Collet. Histoire de l'armement depuis 1945. In: Politique étrangère, n°3 - 1993 - 58ᵉannée. p. 780
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