219 research outputs found
Nitric oxide stimulates human sperm motility via activation of the cyclic GMP/protein kinase G signaling pathway
Transiting exoplanets from the CoRoT space mission. XV. CoRoT-15b: a brown dwarf transiting companion
We report the discovery by the CoRoT space mission of a transiting brown
dwarf orbiting a F7V star with an orbital period of 3.06 days. CoRoT-15b has a
radius of 1.12 +0.30 -0.15 Rjup, a mass of 63.3 +- 4.1 Mjup, and is thus the
second transiting companion lying in the theoretical mass domain of brown
dwarfs. CoRoT-15b is either very young or inflated compared to standard
evolution models, a situation similar to that of M-dwarfs stars orbiting close
to solar-type stars. Spectroscopic constraints and an analysis of the
lightcurve favors a spin period between 2.9 and 3.1 days for the central star,
compatible with a double-synchronisation of the system.Comment: 7 pages, 6 figures, accepted in A&
Parental transfer of the antimicrobial protein LBP/BPI protects Biomphalaria glabrata eggs against oomycete infections
Copyright: © 2013 Baron et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was funded by ANR (ANR-07-BLAN-0214 and ANR-12-EMMA-00O7-01), CNRS and INRA. PvW was financially supported by the BBSRC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
Identification of functional insulin receptors on membranes from an insulin-producing cell line (RINm5F)
Curcumin-loaded solid lipid nanoparticles bypass p-glycoprotein mediated doxorubicin resistance in triple negative breast cancer cells
Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets
We present a detailed spectroscopic study of 93 solar-type stars that are
targets of the NASA/Kepler mission and provide detailed chemical composition of
each target. We find that the overall metallicity is well-represented by Fe
lines. Relative abundances of light elements (CNO) and alpha-elements are
generally higher for low-metallicity stars. Our spectroscopic analysis benefits
from the accurately measured surface gravity from the asteroseismic analysis of
the Kepler light curves. The log g parameter is known to better than 0.03 dex
and is held fixed in the analysis. We compare our Teff determination with a
recent colour calibration of V-K (TYCHO V magnitude minus 2MASS Ks magnitude)
and find very good agreement and a scatter of only 80 K, showing that for other
nearby Kepler targets this index can be used. The asteroseismic log g values
agree very well with the classical determination using Fe1-Fe2 balance,
although we find a small systematic offset of 0.08 dex (asteroseismic log g
values are lower). The abundance patterns of metals, alpha elements, and the
light elements (CNO) show that a simple scaling by [Fe/H] is adequate to
represent the metallicity of the stars, except for the stars with metallicity
below -0.3, where alpha-enhancement becomes important. However, this is only
important for a very small fraction of the Kepler sample. We therefore
recommend that a simple scaling with [Fe/H] be employed in the asteroseismic
analyses of large ensembles of solar-type stars.Comment: MNRAS, in press, 12 page
Waveguide Coupled Resonance Fluorescence from On-Chip Quantum Emitter
Resonantly driven quantum emitters offer a very promising route to obtain highly coherent sources of single photons required for applications in quantum information processing (QIP). Realizing this for on-chip scalable devices would be important for scientific advances and practical applications in the field of integrated quantum optics. Here we report on-chip quantum dot (QD) resonance fluorescence (RF) efficiently coupled into a single-mode waveguide, a key component of a photonic integrated circuit, with a negligible resonant laser background and show that the QD coherence is enhanced by more than a factor of 4 compared to off-resonant excitation. Single-photon behavior is confirmed under resonant excitation, and fast fluctuating charge dynamics are revealed in autocorrelation g(2) measurements. The potential for triggered operation is verified in pulsed RF. These results pave the way to a novel class of integrated quantum-optical devices for on-chip quantum information processing with embedded resonantly driven quantum emitters
Transiting exoplanets from the CoRoT space mission XXI. CoRoT-19b: A low density planet orbiting an old inactive F9V-star
Observations of transiting extrasolar planets are of key importance to our
understanding of planets because their mass, radius, and mass density can be
determined. The CoRoT space mission allows us to achieve a very high
photometric accuracy. By combining CoRoT data with high-precision radial
velocity measurements, we derive precise planetary radii and masses. We report
the discovery of CoRoT-19b, a gas-giant planet transiting an old, inactive
F9V-type star with a period of four days. After excluding alternative physical
configurations mimicking a planetary transit signal, we determine the radius
and mass of the planet by combining CoRoT photometry with high-resolution
spectroscopy obtained with the echelle spectrographs SOPHIE, HARPS, FIES, and
SANDIFORD. To improve the precision of its ephemeris and the epoch, we observed
additional transits with the TRAPPIST and Euler telescopes. Using HARPS spectra
obtained during the transit, we then determine the projected angle between the
spin of the star and the orbit of the planet. We find that the host star of
CoRoT-19b is an inactive F9V-type star close to the end of its main-sequence
life. The host star has a mass M*=1.21+/-0.05 Msun and radius R*=1.65+/-0.04
Rsun. The planet has a mass of Mp=1.11+/-0.06 Mjup and radius of Rp=1.29+/-0.03
Rjup. The resulting bulk density is only rho=0.71+/-0.06 gcm-3, which is much
lower than that for Jupiter. The exoplanet CoRoT-19b is an example of a giant
planet of almost the same mass as Jupiter but a 30% larger radius.Comment: 6 pages, 7 figure
A transiting giant planet with a temperature between 250 K and 430 K
Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274 days on a low eccentricity of 0.11 ± 0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a ‘temperate’ photospheric temperature estimated to be between 250 and 430 K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models with an inferred interior composition consistent with that of Jupiter and Saturn
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