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Gaia Data Release 1 : Pre-processing and source list creation
Context. The first data release from the Gaia mission contains accurate positions and magnitudes for more than a billion sources, and proper motions and parallaxes for the majority of the 2.5 million Hipparcos and Tycho-2 stars. Aims. We describe three essential elements of the initial data treatment leading to this catalogue: the image analysis, the construction of a source list, and the near rea
Gaia Data Release 1 : Summary of the astrometric, photometric, and survey properties
Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Meth
The Gaia mission
Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which th
The Gaia mission : Science, organization and present status
The ESA space astrometry mission Gaia will measure the positions, parallaxes and proper motions of the 1 billion brightest stars on the sky. Expected accuracies are in the 725 as range down to 15 mag and sub-mas accuracies at the faint limit (20 mag). The astrometric data are complemented by low-resolution spectrophotometric data in the 3301000 nm wavelength range and, for the brighter stars, radi
Neck support pillows : a comparative study
BACKGROUND: Special neck support pillows claiming to improve rest and reduce neck pain are currently being advertised.OBJECTIVE: To test whether neck pillows have any positive effect on neck pain and quality of sleep compared with usual pillows and, if so, to find the optimal characteristics of such a pillow.METHODS: Thirty-seven hospital employees and 18 neck patients were asked to test six neck
The oxidation of sulfur(IV)-oxo compounds in the presence of transition metal ions
The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance
Background: The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is among the 100 worst invasive species in the world. As one of the most important crop pests and virus vectors, B. tabaci causes substantial crop losses and poses a serious threat to global food security. Results: We report the 615-Mb high-quality genome sequence of B. tabaci Middle East-Asia Minor 1 (MEAM1), the first genome sequen
Evaluating early-warning indicators of critical transitions in natural aquatic ecosystems
Ecosystems can show sudden and persistent changes in state despite only incremental changes in drivers. Such critical transitions are difficult to predict, because the state of the system often shows little change before the transition. Early-warning indicators (EWIs) are hypothesized to signal the loss of system resilience and have been shown to precede critical transitions in theoretical models,
High-contrast imaging through scattering media using structured illumination and Fourier filtering
We show in this Letter a novel approach for high-contrast imaging through scattering media by combining structured illumination and Fourier filtering (SIF). To assess the image contrast enhancement at different image spatial frequencies, the modulation transfer function is calculated for four detection schemes: (1) no filtering, (2) Fourier filtering, (3) structured illumination, and (4) SIF filte
Holographic imaging with a hard x-ray nanoprobe : Ptychographic versus conventional phase retrieval
We have performed near-field x-ray imaging with simultaneous object and probe reconstruction. By an advanced ptychographic algorithm based on longitudinal and lateral translations, full-field images of nanoscale objects are reconstructed with quantitative contrast values, along with the extended wavefronts used to illuminate the objects. The imaging scheme makes idealizing assumptions on the probe
Homocysteine regulates endothelin type B receptors in vascular smooth muscle cells
Vascular smooth muscle endothelin type B (ETB) receptor is involved in the pathogenesis of cardiovascular diseases (CVDs). Hyperhomocysteinemia is an independent risk factor for CVDs. The present study was designed to examine the hypothesis that homocysteine (Hcy) up-regulates vascular smooth muscle ETB receptors. In vitro experiments were performed in rat superior mesenteric artery (SMA) and vasc
Threshold π - production on the deuteron
An experiment that aims to measure the π- photoproduction cross-section σ(E) on the deuteron γ + 2H → π- + 2p near threshold is discussed. The main concepts of the experimental technique are presented alongside some preliminary signals.
Conjugate priors for Gaussian emission plsa recommender systems
Collaborative filtering for recommender systems seeks to learn and predict user preferences for a collection of items by identifying similarities between users on the basis of their past interest or interaction with the items in question. In this work, we present a conjugate prior regularized extension of Hofmann's Gaussian emission probabilistic latent semantic analysis model, able to overcome th
Electron dynamics in solar energy converting materials
Solar energy is the most abundant renewable energy source available. Conversion of light into electricity and chemical energy are the two major paths for solar energy conversion. Nanostructured organic and hybrid materials are being explored for applications in photovoltaic solar energy conversion, as well as photocatalysis for solar fuel generation. Light harvesting, energy transport, charge phot
On a fixed-point algorithm for structured low-rank approximation and estimation of half-life parameters
We study the problem of decomposing a measured signal as a sum of decaying exponentials. There is a direct connection to sums of these types and positive semi-definite (PSD) Hankel matrices, where the rank of these matrices equals the number of exponentials. We propose to solve the identification problem by forming an optimization problem with a misfit function combined with a rank penalty functio
Characterization of non-vertically aligned semiconductor nanowires by THz emission measurements
In this work terahertz (THz) pulse emission of the non-vertically aligned GaAs core-shell nanowires (NWs) is investigated. THz emission azimuthal dependencies of different NW samples have been measured. It is shown that these measurements together with theoretical calculations could be a very promising method to determine the effective index of refraction (n0) of the NW ensemble. The measurement o
Helicity-dependent terahertz radiation from topological insulator Sb2Te3 thin film by femtosecond optical excitation
We report on terahertz radiation from topological insulator (TI) Sb2Te3 thin film under ultrafast optical excitation with different helicity. Polarity-reversals of the emitted THz radiation were observed as the helicity of optical pulses reversed. The observed phenomena are coincident with the characteristics of the helicity-dependent photocurrent on TIs. Our work demonstrates the potential applic
Healthcare system : A digital green filter for smart health early cervical cancer diagnosis
A color conversion digital filter is implemented which represents a block of a medical imaging system able to assist gynecologists during colposcopic image analysis is presented. The conceived tool is a monitoring system in the field smart health; in fact an early diagnosis could improve the quality of life and the life expectancy of patients. Tree different digital green filters are conceived and