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

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>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<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

Oxytocin, Aggression, and Neural Activity in the Naked Mole-rat

The neuropeptide Oxytocin (OT) is involved in social bonding and pro-social behaviour, however its role in aggression and social status is less clear. The naked mole-rat (Heterocephalus glaber) provides a unique model organism in which to study the effects of OT, exhibiting a social hierarchy that emphasizes certain roles for castes within the colony: soldiers defend colonies against outsiders and workers cooperate within the colony. Here, we wanted to determine whether OT is associated with defensive aggression in soldiers. We compared the behaviour of workers and soldiers using a modified resident-intruder paradigm and quantified neural activity of OT neurons in the hypothalamic paraventricular nucleus (PVN) using immunohistochemistry. Our results show that soldiers were more aggressive than workers when paired with an unfamiliar animal. However, preliminary analyses of the PVN suggest that workers have greater OT neural activity than soldiers, implying that OT is not associated with aggression in soldiers.M.A

RT Prepare: a radiation therapist-delivered intervention reduces psychological distress in women with breast cancer referred for radiotherapy

© 2018 Cancer Research UK Background: The aims of this study were to determine whether a radiation therapist-led patient education intervention (RT Prepare) reduced breasts cancer patients’ psychological distress (primary endpoint); anxiety, depression and concerns about radiotherapy, and increased knowledge of radiotherapy and preparedness (secondary endpoints). Patient health system usage and costs were also assessed. Methods: A multiple-baseline study across three sites. The RT Prepare intervention comprised two consultations with a radiation therapist: prior to treatment planning and on the first day of treatment. Radiation therapists focused on providing sensory and procedural information and addressing patients’ pre-treatment anxiety. Usual care data were collected prior to intervention commencement. Data collection occurred: after meeting their radiation oncologist, prior to treatment planning, first day of treatment and after treatment completion. Multilevel mixed effects regression models were used. Results: In total, 218 usual care and 190 intervention patients participated. Compared with usual care, intervention participants reported lower psychological distress at treatment commencement (p = 0.01); lower concerns about radiotherapy (p < 0.01); higher patient knowledge (p < 0.001); higher preparedness for procedural concerns (p < 0.001) and higher preparedness for sensory-psychological concerns at treatment planning (p < 0.001). Mean within-trial costs per patient were estimated at $AU159 (US$120); mean ongoing costs at $AU35 (US$26). Conclusion: The RT Prepare intervention was effective in reducing breast cancer patients’ psychological distress and preparing patients for treatment. This intervention provides an opportunity for radiation therapists to extend their role into providing patients with information and support prior to treatment to reduce psychological distress