An aperture masking mode for the MICADO instrument

MICADO is a near-IR camera for the Europea ELT, featuring an extended field (75" diameter) for imaging, and also spectrographic and high contrast imaging capabilities. It has been chosen by ESO as one of the two first-light instruments. Although it is ultimately aimed at being fed by the MCAO module called MAORY, MICADO will come with an internal SCAO system that will be complementary to it and will deliver a high performance on axis correction, suitable for coronagraphic and pupil masking applications. The basis of the pupil masking approach is to ensure the stability of the optical transfer function, even in the case of residual errors after AO correction (due to non common path errors and quasi-static aberrations). Preliminary designs of pupil masks are presented. Trade-offs and technical choices, especially regarding redundancy and pupil tracking, are explained.Comment: SPIE 2014 Proceeding -- Montrea

NASSAM: a server to search for and annotate tertiary interactions and motifs in three-dimensional structures of complex RNA molecules

Similarities in the 3D patterns of RNA base interactions or arrangements can provide insights into their functions and roles in stabilization of the RNA 3D structure. Nucleic Acids Search for Substructures and Motifs (NASSAM) is a graph theoretical program that can search for 3D patterns of base arrangements by representing the bases as pseudo-atoms. The geometric relationship of the pseudo-atoms to each other as a pattern can be represented as a labeled graph where the pseudo-atoms are the graph's nodes while the edges are the inter-pseudo-atomic distances. The input files for NASSAM are PDB formatted 3D coordinates. This web server can be used to identify matches of base arrangement patterns in a query structure to annotated patterns that have been reported in the literature or that have possible functional and structural stabilization implications. The NASSAM program is freely accessible without any login requirement at http://mfrlab.org/grafss/nassam/

Restoration of mitochondrial integrity, telomere length, and sensitivity to oxidation by in vitro culture of Fuchs’ endothelial corneal dystrophy cells

PURPOSE. Fuchs’ endothelial corneal dystrophy (FECD), a degenerative disease of the corneal endothelium that leads to vision loss, is a leading cause of corneal transplantation. The cause of this disease is still unknown, but the implication of oxidative stress is strongly suggested. In this study, we analyzed the impact of FECD on mitochondrial DNA (mtDNA) integrity and telomere length, both of which are affected by the oxidative status of the cell. METHODS. We compared the levels of total mtDNA, mtDNA common deletion (4977 bp), and relative telomere length in the corneal endothelial cells of fresh Descemet’s membraneendothelium explants and cultured cells from healthy and late stage FECD subjects. Oxidantantioxidant gene expression and sensitivity to ultraviolet A (UVA)- and H2O2-induced cell death were assessed in cultured cells. RESULTS. Our results revealed increased mtDNA levels and telomere shortening in FECD explants. We also found that cell culture restores a normal phenotype in terms of mtDNA levels, telomere length, oxidant-antioxidant gene expression balance, and sensitivity to oxidative stress-induced cell death in the FECD cells compared with the healthy cells. CONCLUSIONS. Taken together, these results bring new evidence of the implication of oxidative stress in FECD. They also show that FECD does not evenly affect the integrity of corneal endothelial cells and that cell culture can rehabilitate the molecular phenotypes related to oxidative stress by selecting the more functional FECD cells

Modeling RNA loops using sequence homology and geometric constraints

Summary: RNA loop regions are essential structural elements of RNA molecules influencing both their structural and functional properties. We developed RLooM, a web application for homology-based modeling of RNA loops utilizing template structures extracted from the PDB. RLooM allows the insertion and replacement of loop structures of a desired sequence into an existing RNA structure. Furthermore, a comprehensive database of loops in RNA structures can be accessed through the web interface

A probable giant planet imaged in the Beta Pictoris disk

Since the discovery of its dusty disk in 1984, Beta Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~ 10 AU. However, no planets have been detected around this star so far. Our goal was to investigate the close environment of Beta Pic, searching for planetary companion(s). Deep adaptive-optics L'-band images of Beta Pic were recorded using the NaCo instrument at the Very Large Telescope. A faint point-like signal is detected at a projected distance of ~ 8 AU from the star, within the North-East side of the dust disk. Various tests were made to rule out with a good confidence level possible instrumental or atmospheric artifacts. The probability of a foreground or background contaminant is extremely low, based in addition on the analysis of previous deep Hubble Space Telescope images. The object L'=11.2 apparent magnitude would indicate a typical temperature of ~1500 K and a mass of ~ 8 Jovian masses. If confirmed, it could explain the main morphological and dynamical peculiarities of the Beta Pic system. The present detection is unique among A-stars by the proximity of the resolved planet to its parent star. Its closeness and location inside the Beta Pic disk suggest a formation process by core accretion or disk instabilities rather than a binary-like formation process.Comment: 5 pages, 3 figures, 1 table. A&A Letters, in pres

EAGLE multi-object AO concept study for the E-ELT

EAGLE is the multi-object, spatially-resolved, near-IR spectrograph instrument concept for the E-ELT, relying on a distributed Adaptive Optics, so-called Multi Object Adaptive Optics. This paper presents the results of a phase A study. Using 84x84 actuator deformable mirrors, the performed analysis demonstrates that 6 laser guide stars and up to 5 natural guide stars of magnitude R<17, picked-up in a 7.3' diameter patrol field of view, allow us to obtain an overall performance in terms of Ensquared Energy of 35% in a 75x75 mas^2 spaxel at H band, whatever the target direction in the centred 5' science field for median seeing conditions. The computed sky coverage at galactic latitudes |b|~60 is close to 90%.Comment: 6 pages, to appear in the proceedings of the AO4ELT conference, held in Paris, 22-26 June 200

From “Mad Men” to “Math Men”:The Rise of Expertise in Digital Measurement and The Shaping of Online Consumer Freedom

Purpose The authors study how communication agencies became important sites for the rise of measurement expertise in the government of consumer conduct following the development of online consumption. The purpose of this paper is to focus on the processes by which digital measurement developed (within the agencies) as a new legitimate form of expertise, able to produce relevant and detailed knowledge about the government of web users. Design/methodology/approach The authors carried out a field examination in France, predicated on 100 interviews with actors involved in communication consultancy. Drawing on the concepts of governmentality and inter-jurisdictional experimentation, the authors examine how digital measurement expertise acquired legitimacy within agencies. The authors also analyze how contemporary technologies of measurement and surveillance, as operated by in-house digital experts, provide advertising specialists and advertisers with increasingly precise data on consumer conduct and thought. Findings The constitution and legitimization of digital measurement expertise was characterized by experimentation, culminating in the production of persuasive claims of tangibility concerning communication impact, and in relative agreement on the relevance of digital expertise in operating increasingly powerful technologies of measurement and surveillance. Originality/value While the role of experts in promoting and implementing neoliberal governmentality is emphasized in the literature, the study indicates that considerable work is needed to develop and legitimize expertise consequent with neoliberalism. Also, the analysis highlights that the spread of digital measurement expertise and knowledge production in the government of web users constitutes a noteworthy step in the neoliberalization of society. Behind the front of “free” conduct lies an increasingly powerful network of technologies and expertise aimed at rendering consumer conduct knowable and predictable. </jats:sec