616 research outputs found
Mathematical circus clown tricks
The Mathematical Circus project was created in 2011 by the LUDUS association with the main goal of promoting the interest and motivation for learning mathematics. The Mathematical Circus team performs mathematical magic shows where complementary skills are merged to produce a high intervention capacity within a wide geographical range in Portugal. Some tricks are performed by a mathematical clown, a unique
character in the circus world, who brings together the usual foolish characteristics of a clown and the rigorous mathematical knowledge. In this paper we will describe and explain some of the tricks of the Mathematical Circus repertoire involving the clown.info:eu-repo/semantics/publishedVersio
Lyapunov Control on Quantum Open System in Decoherence-free Subspaces
A scheme to drive and manipulate a finite-dimensional quantum system in the
decoherence-free subspaces(DFS) by Lyapunov control is proposed. Control fields
are established by Lyapunov function. This proposal can drive the open quantum
system into the DFS and manipulate it to any desired eigenstate of the free
Hamiltonian. An example which consists of a four-level system with three
long-lived states driven by two lasers is presented to exemplify the scheme. We
have performed numerical simulations for the dynamics of the four-level system,
which show that the scheme works good.Comment: 5 pages, 6 figure
Optical mapping of neuronal activity during seizures in zebrafish
Mapping neuronal activity during the onset and propagation of epileptic seizures can provide a better understanding of the mechanisms underlying this pathology and improve our approaches to the development of new drugs. Recently, zebrafish has become an important model for studying epilepsy both in basic research and in drug discovery. Here, we employed a transgenic line with pan-neuronal expression of the genetically-encoded calcium indicator GCaMP6s to measure neuronal activity in zebrafish larvae during seizures induced by pentylenetretrazole (PTZ). With this approach, we mapped neuronal activity in different areas of the larval brain, demonstrating the high sensitivity of this method to different levels of alteration, as induced by increasing PTZ concentrations, and the rescuing effect of an anti-epileptic drug. We also present simultaneous measurements of brain and locomotor activity, as well as a high-throughput assay, demonstrating that GCaMP measurements can complement behavioural assays for the detection of subclinical epileptic seizures, thus enabling future investigations on human hypomorphic mutations and more effective drug screening methods. Notably, the methodology described here can be easily applied to the study of many human neuropathologies modelled in zebrafish, allowing a simple and yet detailed investigation of brain activity alterations associated with the pathological phenotype
Evaluation de la stratĂ©gie dâĂ©limination de la rougeole 2011-2015
La stratĂ©gie dâĂ©limination de la rougeole 2011-2015 Ă©laborĂ©e et mise en oeuvre par lâOFSP a Ă©tĂ© Ă©valuĂ©e en utilisant diverses approches mĂ©thodologiques complĂ©mentaires. Les principaux rĂ©sultats montrent quâun large consensus sur la stratĂ©gie a Ă©tĂ© obtenu sous lâimpulsion de lâOFSP et que tous les cantons ont mis en oeuvre des mesures visant Ă augmenter la couverture vaccinale. Une augmentation de la couverture vaccinale, du rattrapage vaccinal et une rĂ©duction des disparitĂ©s cantonales de couverture vaccinale ont Ă©tĂ© observĂ©es. Cependant lâobjectif stratĂ©gique de couverture vaccinale 2 doses Ă lâĂąge de 2 ans nâa pas Ă©tĂ© obtenu dans tous les cantons pour lesquels on dispose dâune mesure en 2014-2015. Il est probable que la stratĂ©gie nâa pas encore dĂ©ployĂ© tous ses effets. Les mesures mises en oeuvre pour prĂ©venir et contenir les flambĂ©es Ă©pidĂ©miques et qui visent Ă augmenter la couverture vaccinale devraient ĂȘtre poursuivies
Feedback control of spin systems
The feedback stabilization problem for ensembles of coupled spin 1/2 systems
is discussed from a control theoretic perspective. The noninvasive nature of
the bulk measurement allows for a fully unitary and deterministic closed loop.
The Lyapunov-based feedback design presented does not require spins that are
selectively addressable. With this method, it is possible to obtain control
inputs also for difficult tasks, like suppressing undesired couplings in
identical spin systems.Comment: 16 pages, 15 figure
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