445 research outputs found
Recombination rates according to Fiston-Lavier et al. 2010 and Comeron et al. 2012 for D. melanogaster genome release 6
No full textThis file contains genomic coordinates and its recombination rate as determined by the recombination rate calculator (RRC) (Fiston-Lavier et al. 2010) and (Comeron et al. 2012) (http://petrov.stanford.edu/cgi-bin/recombination-rates_updateR5.pl). Such coordinates were originally calculated based on release 5 of D. melanogaster genome so we converted them to release 6 coordinates using the coord_converter.pl script from FlyBase (Gramates et al. 2017). We considered a region to have high recombination rates (HRR) when both recombination estimates were greater than 0.This file contains recombination rates values according to two estimations: Fiston-Lavier et al. 2010 and Comeron et al. 2012 for D. melanogaster genome release 6.This file was created in the framework of the ERC grant number H2020-ERC-2014-CoG-647900, funded by the European Commission (https://erc.europa.eu/).Peer reviewe
A Young Very Low Mass Object Surrounded by Warm Dust
No full textWe present a complete low-resolution (R~100) near-IR spectrum of the substellar object GY11, a member of the ρ Ophiuchi young association. The object is remarkable because of its low estimated mass and age and because it is associated with a mid-IR source, an indication of a surrounding dusty disk. Based on the comparison of our spectrum with similar spectra of field M dwarfs and atmospheric models, we obtain revised estimates of the spectral type, effective temperature, and luminosity of the central object. These parameters are used to place the object on a H-R diagram and to compare it with the predictions of pre-main-sequence evolutionary models. Our analysis suggests that the central object has a very low mass, probably below the deuterium-burning limit and in the range of 8-12 MJ, and a young age of less than 1 Myr. The IR excess is shown to be consistent with the emission of a flared, irradiated disk similar to those found in more massive brown dwarf and T Tauri systems. This result suggests that substellar objects, even the so-called isolated planetary mass objects, found in young stellar associations are produced in a similar fashion as stars, by core contraction and gravitational collapse
Measurements of the Beam-Wave Fluctuations over a 142-km Atmospheric Path
No full textAn optical link has been established between the Canary Islands La Palma and Tenerife. A 1064-nm transmitting laser was located on La Palma whereas a BPSK communication receiver and measurement instruments were installed in ESA's OGS on Tenerife. Beside the demonstration of a high-data-rate coherent signal transmission, the goal of the experiment was to measure the effects of the atmosphere on the beam propagation in order to estimate its impact on optical links. Wavefront distortions have been investigated by means of a DIMM instrument and scintillation was observed by imaging the pupil of the OGS telescope on a CCD camera. Strong scintillation was observed during the entire campaign with scintillation peaks at sunsets and sunrises, and saturation at about noon. Because of the narrowness of the beam (10-μrad divergence), beam wander has been a serious issue. Statistical results are compared with theory
An automatic light rain detection algorithm on NASA MPLNET lidar observations in the frame of WMO GALION project
No full textThe water cycle strongly influences life on Earth. In particular, the precipitation modifies the atmospheric column thermodynamics through the process of evaporation and serves as a proxy for latent heat modulation. For this reason, a correct precipitation parameterization (especially low-intensity precipitation) at global scale, bedsides improving our understanding of the hydrological cycle, it is crucial to reduce the associated uncertainty of the global climate models to correctly forecast future scenarios, i.e. to apply fast mitigation strategies. In this study we developed an algorithm to automatically detect precipitation from lidar measurements obtained by the National and Aeronautics Space Administration (NASA) Micropulse lidar network (MPLNET) permanent observational site in Goddard. The algorithm, once full operational, will deliver in Near Real Time (latency 1.5h) a new rain mask product that will be publicly available on MPLNET website as part of the new Version 3 Level 1.5 data. The methodology, based on an image processing technique, can detect only light precipitation events (defined by intensity and duration) as the morphological filters used through the detection process are applied on the lidar volume depolarization ratio range corrected composite images, i.e. heavy rain events are unusable as the lidar signal is completely extinguished after few meters in the precipitation or no signal detected because of the water accumulated on the receiver optics. Results from the algorithm, besides filling a gap in precipitation and virga detection by radars, are of particular interest for the scientific community because will help to better understand long-term aerosol-cloud interactions and aerosol atmospheric removal (scavenging effect) by rain as multi-year database being available for several MPLNET permanent observational sites across the globe. Moreover, we developed the automatic algorithm at Universitat Politecnica de Catalunya (UPC) Barcelona, the unique permanent observation station member of MPLNET and the European Aerosol Lidar Network (EARLINET) In the future the algorithm can be then easily applied to any other lidar and/or ceilometer network infrastructure in the frame of World Meteorological Organization (WMO) Global Aerosol Watch (GAW) aerosol lidar observation network (GALION
Estimation of aerosol direct radiative forcing in Lecce during the 2013 ADRIMED campaign
No full text
Establishment of endolithic populations of extremophilic Cyanidiales (Rhodophyta)
No full textAbstract Background Cyanidiales are unicellular extremophilic red algae that inhabit acidic and high temperature sites around hot springs and have also adapted to life in endolithic and interlithic habitats. Comparative genomic analysis of Cyanidioschyzon merolae and Galdieria sulphuraria predicts that the latter may be more broadly distributed in extreme environments because its genome contains membrane transporters involved in the uptake of reduced carbon compounds that are absent from C. merolae. Analysis of an endolithic site in the Phlegrean Fields near Naples, Italy is consistent with this prediction showing this population to be comprised solely of the newly described lineage Galdieria-B and C. merolae to be limited to humid habitats. Here, we conducted an environmental PCR survey of another extreme environment in Tuscany, Italy and contrasted Cyanidiales population structure at endolithic and interlithic habitats in Naples and Tuscany. Results We find a second Galdieria lineage (Galdieria-A) in endolithic and interlithic habitats in Tuscany but surprisingly Cyanidium was also present at these sites. The photoautotrophic Cyanidium apparently survives below the rock surface where sufficient light is available for photosynthesis. C. merolae is absent from all endolithic and interlithic sites in Tuscany. Population genetic analyses of a partial calmodulin gene fragment suggest a recent establishment or recurrent gene flow between populations in Tuscany, whereas the highly structured Galdieria-B population in Naples likely originated from 2–3 founder events. We find evidence of several recombination events across the calmodulin gene, potentially indicating the presence of sexual reproduction in the Tuscany populations. Conclusion Our study provides important data regarding population structure in extreme endolithic environments and insights into how Cyanidiales may be established in and adapt to these hostile environments.</p
On the temperature stability requirements of free-running Nd:YAG lasers for atmospheric temperature profiling through the rotational Raman technique
No full textWe assess the temperature stability requirements of unseeded Nd:YAG lasers in lidar systems for atmospheric temperature profiling through the rotational Raman technique. Taking as a reference a system using a seeded laser assumed to emit pulses of negligible spectral width and free of wavelength drifts, we estimate first the effect of the pulse spectral widening of the unseeded laser on the output of the interference filters, and then we derive the limits of the allowable wavelength drift for a given bias in the temperature measurement that would add to the noise-induced uncertainty. Finally, using spectroscopic data, we relate the allowable wavelength drift to allowable temperature variations in the YAG rod. We find that, in order to keep the bias affecting atmospheric temperature measurements smaller than 1 K, the Nd:YAG rod temperature should also be kept within a variation range of 1 K
On the massive star contents of Cygnus OB2
No full textWe present a near-infrared spectroscopic survey of a
large area centered on the Cygnus OB2 association aimed at
constraining its massive star contents. Our goal is to establish a
nearly complete list of O-type members of the association, both
to examine recent claims based on starcounts that suggest a
richer content than previously thought, and to provide a
suitable database for further studies of the entire high-mass end
of one of the richest associations of the Galaxy. The target
selection is based on the JHK photometry published in the 2MASS
all-sky survey. We identify 46 new early-type candidates, most of
them expected to be O-type stars, plus 16 new stars with emission
in Brγ and often in other lines as well, characteristic of
evolved massive stars undergoing intense mass loss. We also
present spectra of three luminous stars with CO overtone
emission, one of them having also intense H2 emission and
being associated with compact nebulosity. By considering our
findings, those of other authors, and plausible completeness
corrections, we estimate the number of O-type stars or stars
having evolved from a O-type progenitor to be 90–100, slightly
below, but compatible with, most recent starcounts estimates by
Knödlseder (2000, A&A, 360, 539). These results support the
notion that Cygnus OB2 may be considered as a young globular
cluster. The lists of new members that we provide, in particular
those with emission lines, should be a useful resource for future
investigations of Cygnus OB2 itself, as well as of very massive
stellar evolution by providing a nearby, abundant sample of stars
sharing a common environment
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