Characterization of the LIGO detectors during their sixth science run

31 pages, 13 figures - See paper for full list of authorsInternational audienceIn 2009-2010, the Laser Interferometer Gravitational-wave Observatory (LIGO) operated together with international partners Virgo and GEO600 as a network to search for gravitational waves of astrophysical origin. The sensitiv- ity of these detectors was limited by a combination of noise sources inherent to the instrumental design and its environment, often localized in time or frequency, that couple into the gravitational-wave readout. Here we review the performance of the LIGO instruments during this epoch, the work done to characterize the de- tectors and their data, and the effect that transient and continuous noise artefacts have on the sensitivity of LIGO to a variety of astrophysical sources

Searching for stochastic gravitational waves using data from the two co-located LIGO Hanford detectors

21 pages, 10 figures, 5 tables, see paper for full list of authorsInternational audienceSearches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a co-located detector pair is more sensitive to a gravitational-wave background than a non-co-located detector pair. However, co-located detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of co-located detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO's fifth science run. At low frequencies, 40 - 460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460-1000 Hz, these techniques are sufficient to set a 95% confidence level (C.L.) upper limit on the gravitational-wave energy density of \Omega(f)<7.7 x 10^{-4} (f/ 900 Hz)^3, which improves on the previous upper limit by a factor of ∼180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors

Peptide immobilisation on porous silicon surface for metal ions detection

In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis) peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

L'échographie cardiaque normale et pathologique en néonatologie (création d'un cd-rom d'auto-apprentissage interactif destiné aux internes)

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

0351: French experience in tricuspid valve-in-valve implantation for bioprosthetic valve failure

Tricuspid valve-in-valve (VIV) implantation has recently emerged as a possible therapeutic option when a bioprosthetic valve degenerates. A French retrospective study is reported.From 2010 to end 2014, 9 patients underwent tricuspid VIV implantation. There were 4 females and 5 males. Pts were in functional NYHA class III. Seven pts had congenital heart disease, 1 pt a rheumatic disease, 1 pt a cardiomyopathy. Causes for implantation were tricuspid stenosis (n = 4), a mixed lesion combining tricuspid stenosis and regurgitation (n = 4), and one tricuspid regurgitation. In addition, 2 of them suffered from protein losing enteropathy (PLE).Implantation was performed under general anaesthesia using a femoral approach at a mean age of 29.5±18 years (9-60 years). Two pts underwent pre-dilatation of the lesion and a pre-stenting was performed in 6. VIV implantation was realized under pacing in 3 pts. A 22-mm Melody valve (Medtronic) was implanted in 6 pts, and an Edwards Sapien valve in 3 (one 23-mm, one 26mm, and one 29-mm valve). Implantation succeeded in all despite 2 embolizations (1 in RA and 1 in RV); the embolized stent could be stabilized within the tricuspid annulus in both by a self-expandable stent before subsequent successful VIV implantation using a second valved stent. During follow-up (mean 10 months and up to 24 months), all pts but one were clinically ameliorated (mean functional NYHA class II) including the 2 pts with PLE (increase in albumin level). The mean tricuspid gradient decreased significantly from 9.4±2.3mm Hg before to 3.9±0.4mm Hg after implantation. Two pts died during follow-up but death was not valved stent related.To conclude, tricuspid VIV implantation is an effective procedure using both the Melody and the Edwards Sapien valves. Knowledge of the true minimal diameter is the key point to choose the appropriate valved stent. This promising technique has good immediate and mid-term results but further studies with longer follow-up and including more pts are necessar