1,424 research outputs found
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 Fuchsâ endothelial corneal dystrophy cells
PURPOSE. Fuchsâ 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 Descemetâs 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 âMad Menâ to âMath Menâ: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 âfreeâ conduct lies an increasingly powerful network of technologies and expertise aimed at rendering consumer conduct knowable and predictable.
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