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

Developmental study identifies the ages at which the processes involved in the perception of verticality and in postural stability occur

International audienceAim: The aim of this study was to understand the role played by visual information on the development of verticality and postural stability in healthy children.Methods: The study comprised 66 healthy children from 4.0 to 15.7 years of age. Postural performances were recorded with a TechnoConcept platform. At the same time, the children's perception of subjective visual vertical (SVV) was recorded while they adjusted a vertical fluorescent line, either in the dark or in the presence of perturbing visual stimuli. Two testing control conditions without an SVV task were also performed by all of the children: static posturographic recording with open eyes and closed eyes.Results: Postural measurements provided evidence of a correlation between the children's age and the tasks performed. Postural stability improved with age until eight to nine years, and SVV performance improved after 10–11 years. After these ages, postural and SVV capabilities did not change until at least 15 years of age.Conclusion: Our findings suggest that the maturation of cortical and central processes involved in both the perception of verticality and in postural stability took place during childhood. However, maturation occurred later for vertical perception, which could imply delayed maturation of sensory integration processes

Spatial and temporal postural analysis in children born prematurely

The aim of this study was to compare postural stability in a group of preterm-born children aged 4-6 years old and in a group of age-matched full-term control children by exploring both spatial and temporal analysis of the Center of Pressure (CoP). Twenty-nine children born prematurely (mean age: 5.38±0.17) and twenty-nine age-matched full-term control children participated in this study. Postural control was tested on both a stable and an unstable platform (from Framiral®) in three different visual conditions: eyes open fixating a target, eyes closed, and with vision perturbed by optokinetic stimulation. We observed a significant increase of both surface area and mean velocity of the CoP in pre-term children compared to full-term control children, particularly in an unstable postural condition. The spectral power indices increased significantly in pre-term children with respect to full-term control children, while the cancelling time was not different between the two groups of children tested. We suggested that poor postural stability observed in preterm children could be due to immaturity of the cortical processes (the occipital parietal prefrontal cortex) involved in motor control. Preterm children could have an inappropriate compensation of sensory inputs when they are tested in difficult postural and/or visual conditions

Endoscopic management with multiple plastic stents of anastomotic biliary stricture following liver transplantation: long-term results

Background and aims: Anastomotic biliary stricture (ABS) is the most common biliary complication after orthotopic liver transplantation (OLT) and can be successfully managed endoscopically. The long-term results of a protocol using placement of multiple plastic stents to treat ABS following OLT were analyzed. Methods: All patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) for OLT-related biliary complications at our Endoscopy Unit between July 1994 and March 2012 were retrospectively identified from the ERCP database. Patients with an ABS treated with an increasing number of plastic stents were included in the study. Follow-up after stent removal was obtained by telephone contact with the patient and/or referring physician and by liver function tests (LFTs) evaluation. Results: 56 patients, treated with an increasing number of plastic stents until resolution of the stricture, were included. Five patients were then excluded (unrelated death during treatment, n = 3; incomplete treatment because of poor compliance, n = 2), and 51/56 patients reached study end points and were included in the analysis. Resolution of ABS was obtained in 50/51 patients; 1 patient required hepaticojejunostomy because of failure to pass the stricture with the guidewire (per protocol resolution, 98 %). Mean duration of endoscopic treatment was 11.5 months, with a median 4 ERCPs per patient. Immediate ERCP-related adverse events occurred in 3/56 patients (5.4 %). After a median follow-up of 5.8 years from stent removal, 3/50 patients (6 %) had recurrence of ABS. These 3 patients were successfully treated again endoscopically and are asymptomatic after a further median follow-up of 5.6 years. Conclusions: At long-term follow-up, endoscopic treatment with multiple plastic stents of ABS following OLT appeared to be effective in most patients. Stricture recurrence is rare and can be successfully treated again endoscopically

Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo

Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software

Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo

International audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]† Deceased, August 2020