Newton algorithm for Hamiltonian characterization in quantum control

We propose a Newton algorithm to characterize the Hamiltonian of a quantum system interacting with a given laser field. The algorithm is based on the assumption that the evolution operator of the system is perfectly known at a fixed time. The computational scheme uses the Crank-Nicholson approximation to explicitly determine the derivatives of the propagator with respect to the Hamiltonians of the system. In order to globalize this algorithm, we use a continuation method that improves its convergence properties. This technique is applied to a two-level quantum system and to a molecular one with a double-well potential. The numerical tests show that accurate estimates of the unknown parameters are obtained in some cases. We discuss the numerical limits of the algorithm in terms of basin of convergence and non uniqueness of the solution.Comment: 18 pages, 7 figure

Extracellular vesicles from adipose tissue - a potential role in obesity and type 2 diabetes?

Adipose tissue plays a key role in the development of insulin resistance and its pathological sequelae such as type 2 diabetes and non-alcoholic fatty liver disease. Dysfunction in the adipose tissue response to storing excess fatty acids as triglyceride can lead to adipose tissue inflammation and spillover of fatty acids from this tissue and accumulation of fatty acids as lipid droplets in ectopic sites such as liver and muscle. Extracellular vesicles (EV) are released from adipocytes and have been proposed to be involved in adipocyte/macrophage crosstalk and to affect insulin signalling and TGFβ expression in liver cells leading to metabolic disease. Furthermore EV produced by adipose tissue-derived mesenchymal stem cells (ADSC) can promote angiogenesis and cancer cell migration and have neuroprotective and neuroregenerative properties. ADSC EV have therapeutic potential in vascular and neurodegenerative disease and may also be used to target specific functional miRNAs to cells. Obesity is associated with an increase in adipose-derived EV which may be related to the metabolic complications of obesity. This review aims to discuss EV produced by adipose tissue and their potential impact on metabolic diseases associated with obesity

Production of Long-Lived Ultracold Li2 Molecules from a Fermi gas

We create weakly-bound Li2 molecules from a degenerate two component Fermi gas by sweeping a magnetic field across a Feshbach resonance. The atom-molecule transfer efficiency can reach 85% and is studied as a function of magnetic field and initial temperature. The bosonic molecules remain trapped for 0.5 s and their temperature is within a factor of 2 from the Bose-Einstein condensation temperature. A thermodynamical model reproduces qualitatively the experimental findings

Between distance and proximity: nature parks and the city in Switzerland

Urban Nature Parks do not exist in Switzerland. A debate regarding their establishment in 2010 petered out. This failure exemplifies a representation of nature in the Swiss parks system, which should stand very far removed from the city. Since the establishment of Parks of National Importance in 2006, human activity has been tolerated under the condition that it is considered rural. Because it is neither wild, with the exception of a few rewilded forests, nor rural, urban nature has no place in this policy. However, the ‘a-urban’ conception of the parks policy in Switzerland does not preclude the existence of close links between cities and nature parks for obvious reasons of spatial and functional proximity. Hence, although the nature parks should be far removed from the cities by definition, they are very close to them by reality. Furthermore, this paradoxical situation is accompanied by the emergence of local solutions, outside the framework of the official regulation of nature parks, for ensuring the conservation of open highly urbanized non-built areas at the outskirts of cities. However those Agglomeration Parks are far from constituting an equivalent alternative to the national strategy with no legal status, an absence of dedicated funding and their very large target gathered under the banner of “open spaces”

Compte rendu du livre de B. Lizet (2015) : Une ethnologue au Jardin des Plantes -dix petits terrains.

No abstract available