Enhancing retinal images by nonlinear registration

Being able to image the human retina in high resolution opens a new era in many important fields, such as pharmacological research for retinal diseases, researches in human cognition, nervous system, metabolism and blood stream, to name a few. In this paper, we propose to share the knowledge acquired in the fields of optics and imaging in solar astrophysics in order to improve the retinal imaging at very high spatial resolution in the perspective to perform a medical diagnosis. The main purpose would be to assist health care practitioners by enhancing retinal images and detect abnormal features. We apply a nonlinear registration method using local correlation tracking to increase the field of view and follow structure evolutions using correlation techniques borrowed from solar astronomy technique expertise. Another purpose is to define the tracer of movements after analyzing local correlations to follow the proper motions of an image from one moment to another, such as changes in optical flows that would be of high interest in a medical diagnosis.Comment: 21 pages, 7 figures, submitted to Optics Communication

A functional study of AUXILIN-LIKE1 and 2, two putative clathrin uncoating factors in Arabidopsis

Clathrin-mediated endocytosis (CME) is a cellular trafficking process in which cargoes and lipids are internalized from the plasma membrane into vesicles coated with clathrin and adaptor proteins. CME is essential for many developmental and physiological processes in plants, but its underlying mechanism is not well characterized compared with that in yeast and animal systems. Here, we searched for new factors involved in CME in Arabidopsis thaliana by performing tandem affinity purification of proteins that interact with clathrin light chain, a principal component of the clathrin coat. Among the confirmed interactors, we found two putative homologs of the clathrin-coat uncoating factor auxilin previously described in non-plant systems. Overexpression of AUXILIN-LIKE1 and AUXILIN-LIKE2 in Arabidopsis caused an arrest of seedling growth and development. This was concomitant with inhibited endocytosis due to blocking of clathrin recruitment after the initial step of adaptor protein binding to the plasma membrane. By contrast, auxilin-like1/2 loss-of-function lines did not present endocytosis-related developmental or cellular phenotypes under normal growth conditions. This work contributes to the ongoing characterization of the endocytotic machinery in plants and provides a robust tool for conditionally and specifically interfering with CME in Arabidopsis

Automatic sensitivity-adjustment for a curvature sensor

There are different techniques to sense the wavefront phase-distortions due to atmospheric turbulence. Curvature sensors are practical in their sensitivity being adjustable to the prevailing atmospheric conditions. Even at the best sites, the turbulence intensity has been found to vary at times over only a few minutes and regularly over longer periods. Two methods to automatically adjust the sensitivity of a curvature sensor are proposed: First, the defocus distance can be adjusted prior to the adaptive-optics (AO) loop through the acquisition of a long exposure image and can then be kept constant. Secondly, the defocus distance can be changed during the AO loop, based on the voltage values sent to the deformable mirror. We demonstrate that the performance increase - assessed in terms of the image Strehl-ratio - can be significant.Comment: Accepted for publication in the adaptive-optics feature of Applied Optic

Engine oil acidity detection using solid state ion selective electrodes

Initial results from oil acidity measurements using thick film electrodes are presented. The results suggest that as the oil degrades, its pH/acidity follows a specific trend. Furthermore, an investigation into the feasibility of detecting changes in oil acidity (i.e. TAN value) using ion selective electrodes fabricated utilising thick film technology is presented. The thick-film (screen printing) technique is a decent means for the mass production of rugged, compact and disposable sensors as many such devices can be printed at the same time making them very cost effective to manufacture. Thick-Film ion selective and reference electrodes were fabricated, calibrated and tested in different oil samples varying its acidity. Ruthenium oxide (RuO2) pH sensitive electrodes were screen printed and were used against silver/silver chloride (Ag/AgCl) reference electrodes as well as a commercial glass Ag/AgCl reference electrode. The potentiometric sets of electrodes were calibrated in pH 4, 7 and 10 buffers in a cyclic manner and the voltage was recorded using a high input impedance voltmete

A new fully two-dimensional conservative semi-Lagrangian method: applications on polar grids, from diocotron instability to ITG turbulence

article 252International audienceWhile developing a new semi-Lagrangian solver, the gap between a linear Landau run in 1Dx1Dand a 5D gyrokinetic simulation in toroidal geometry is quite huge. Intermediate test cases are welcomefor testing the code. A new fully two-dimensional conservative semi-Lagrangian (CSL) method is presentedhere and is validated on 2D polar geometries. We consider here as building block, a 2D guiding-centertype equation on an annulus and apply it on two test cases. First, we revisit a 2D test case previouslydone with a PIC approach [18] and detail the boundary conditions. Second, we consider a 4D drift-kineticslab simulation (see [10]). In both cases, the new method appears to be a good alternative to deal withthis type of models since it improves the lack of mass conservation of the standard semi-Lagrangian (BSL)method

Formalismo Tcheco-Russo

The present work is dedicated to the discussion of the influence of Russian formalism over the Prague Linguistic Circle and the Czech structuralism as a whole. For that, the author presents the reader with different points of view, including from the Czech scholars themselves. The conclusion reached by the author is that structuralism is not a continuation or an evolution of the formalism, but a trend in itself that opposes its predecessor.O presente trabalho é dedicado à discussão da influência do formalismo russo sobre o Círculo Lingüístico de Praga e o estruturalismo tcheco como um todo. Para tanto, o autor apresenta ao leitor diversos pontos de vista, inclusive dos próprios estudiosos tchecos. A conclusão a que chega o autor é que o estruturalismo não é uma continuação ou uma evolução do formalismo, mas uma tendência em si mesma que se opõe a seu antecessor

ArtEAST Babi Badalov

The artist Babi Badalov, a cultural nomad born in Soviet Azerbaijan, places handwritten texts in galleries, museums and public spaces. They are characterised by their activist content, but above all his works deal with staged misunderstanding and the hybridity of language / languages as a creative principle. The essay describes this strategy as a specific treatment of migration experience in terms of linguistic and artistic practice

Study of the dynamic aberrations of the human tear film

The dynamic aberrations introduced by the human tear film are studied by measuring the topography of the tear film surface on 14 subjects using a curvature sensing setup. The RMS wavefront error variation of the data obtained is presented showing the non-negligible contribution of the tear film to overall eye aberrations. The tear film wavefronts are decomposed in their constituent Zernike terms, showing stronger contributions from 4th order terms and terms with vertical symmetry, and the temporal behaviour of these aberrations is analysed

Problems with the prospective connected autonomous vehicles regulation : Finding a fair balance versus the instinct for self-preservation

There would seem to be a potential regulatory problem with the crash algorithms for connected and autonomous vehicles that (normally) "kick in" should a crash be inevitable. Although the general regulatory considerations which have been put forward tend to seek a "fair balance" that would protect various users of the roads, a configuration which shielded other parties at the cost of the car user could be seen as posing an existential threat to the user by encroaching on his or her right to self-preservation. "Hacking the system" (i.e. modifying the configuration in order to obtain a more favourable outcome for the user) could therefore be understood as acting on one's instinct for self-preservation and - though illegal - could in certain situations turn out to be an action that is not punishable in law. The present article argues that in certain real post-crash situations, a person who has modified the code for his or her own benefit could be exonerated on the basis of existing legal provisions and thus go unpunished. This could create unforeseen flaws in the connected autonomous vehicles regulatory system.Peer reviewe