Black holes in the low mass gap: Implications for gravitational wave observations

Binary neutron-star mergers will predominantly produce black-hole remnants of mass $\sim 3-4\,M_{\odot}$, thus populating the putative \emph{low mass gap} between neutron stars and stellar-mass black holes. If these low-mass black holes are in dense astrophysical environments, mass segregation could lead to "second-generation" compact binaries merging within a Hubble time. In this paper, we investigate possible signatures of such low-mass compact binary mergers in gravitational-wave observations. We show that this unique population of objects, if present, will be uncovered by the third-generation gravitational-wave detectors, such as Cosmic Explorer and Einstein Telescope. Future joint measurements of chirp mass ${\cal M}$ and effective spin $\chi_{\rm eff}$ could clarify the formation scenario of compact objects in the low mass gap. As a case study, we show that the recent detection of GW190425 (along with GW170817) favors a double Gaussian mass model for neutron stars, under the assumption that the primary in GW190425 is a black hole formed from a previous binary neutron star merger.Comment: 8 pages, 4 figures, 1 table. v4: matches the version accepted for publication in Phys. Rev.

Comparison of Gravitational Wave Detector Network Sky Localization Approximations

Gravitational waves emitted during compact binary coalescences are a promising source for gravitational-wave detector networks. The accuracy with which the location of the source on the sky can be inferred from gravitational wave data is a limiting factor for several potential scientific goals of gravitational-wave astronomy, including multi-messenger observations. Various methods have been used to estimate the ability of a proposed network to localize sources. Here we compare two techniques for predicting the uncertainty of sky localization -- timing triangulation and the Fisher information matrix approximations -- with Bayesian inference on the full, coherent data set. We find that timing triangulation alone tends to over-estimate the uncertainty in sky localization by a median factor of $4$ for a set of signals from non-spinning compact object binaries ranging up to a total mass of $20 M_\odot$, and the over-estimation increases with the mass of the system. We find that average predictions can be brought to better agreement by the inclusion of phase consistency information in timing-triangulation techniques. However, even after corrections, these techniques can yield significantly different results to the full analysis on specific mock signals. Thus, while the approximate techniques may be useful in providing rapid, large scale estimates of network localization capability, the fully coherent Bayesian analysis gives more robust results for individual signals, particularly in the presence of detector noise.Comment: 11 pages, 7 Figure

European Youth Cybercrime, Online Harm and Online Risk Taking: 2022 Research Report

Researching cybercriminality to design new methods to prevent, investigate and mitigate cybercriminal behaviour. This is one of the largest studies to date exploring youth cybercriminality. The survey is informed by 5 key disciplines: cyberpsychology, criminology, psychology, neuroscience, and digital anthropology Results confirm that cybercrime and cyberdeviance is prevalent-survey finds that two thirds (69%) of European youth self-report to have committed at least one form of cybercrime or online harm or risk taking, and just under half 47.76% (N=3808) report to have engaged in criminal behaviour online, from summer of 2020 to the summer of 2021 Survey finds that males are more likely (74%) than females (65%) to self-report having been involved in at least one form of cybercrime or online harm or risk taking in the last year and results confirm that the majority of cybercrime and cyberdeviant behaviours are gendered. Survey analysis demonstrates that cybercriminal and online harm or risk taking behaviours form a cluster of 11 behaviours that are highly interrelated (CcCd-Cluster) and that cybercrime and online harm or risk taking behaviours represent a spectrum (CcCd-Spectrum) A significant shift from a siloed, categorical approach is needed in terms of how cybercrimes are conceptualised, investigated, and legislated

CC-DRIVER Policy Brief No. 8: European Youth Survey

This policy brief contains key findings from the CC-DRIVER 2021 European Youth Survey and corresponding conclusions. This brief is designed for all professionals working within the area of cybercrime and key stakeholders, including LEAs, Academics, Criminal Justice, Policy Makers, and Educators. The lack of clarity surrounding the term cybercrime has significant impact on society, cybercrime policy, legal intervention, and academic research. No single classification system fully encapsulated cybercrime concepts or accurately reflected the nebulous nature of cybercrime acts. There is remaining ambiguity as to what exactly constitutes a cybercrime, and it is likely that a clear conceptualisation of cybercrime will continue to be challenged. This review presents key cybercrime definitions, categorisations of cybercrime and typologies of cybercrime. This review presents a new framework with which to conceptualise cybercrime

Research on Protection of Minors: A literature Review and Interconnected Frameworks Implications for VSP Regulation and Beyond

Ofcom commissioned the Institute for Connected Communities at the University of East London (UEL) to conduct this research in order to help inform VSP guidance. The particular areas of interest identified by Ofcom were:Which risks of harm are most prevalent among minors on VSPs (considering both quantitative and qualitative evidence)? How do these harms manifest on VSPs? Are different VSP characteristics relevant to protecting users from harms

Assessing the Feasibility of a Parent Life Coaching Intervention to Support Parents and Children Who Have Experienced Domestic Violence and Abuse

This is the final version. Available on open access from Springer Verlag via the DOI in this recordData accessibility: Due to ethical concerns, the research data supporting this publication are not publicly available.Children exposed to domestic violence are at risk for a range of psychosocial difficulties, which may be mitigated by improving their caregiver’s mental health and capacity to parent. Life coaching is a promising behaviour change approach for improving the empowerment, efficacy and well-being of carers who are parenting alone following domestic violence. This study evaluated the feasibility of a novel life coaching programme. Using a pre- post-test design, the Family Vision© (FV) programme was implemented in two community settings. The programme was offered to single mothers with experience of domestic violence. Feasibility data were collected using satisfaction forms, semi-structured interviews and focus groups with parents, facilitators and managers. Mothers’ self-reports about their mental well-being; empowerment and self-efficacy were collected, as well as the quality of their parent-child relationships and children’s psychosocial functioning, using standardised measures at baseline and end of programme. The programme was found to have good acceptability for this population of parents and was considered feasible to deliver in the two community settings where it was piloted. There were indications that women who completed the programme had improved mental well-being, as well as improved empowerment and efficacy by the end of the programme. The FV programme is feasible to implement and could support positive change for single parents with respect to their mental health and capacity to parent effectively. Demonstrated mediators, these effects could also promote children’s health and well-being. Feasibility for a randomised trial and wider scale-up in the community is now required.Economic and Social Research Council (ESRC

Microwave Penetration and Attenuation in Desert Soil: A Field Experiment with the Shuttle Imaging Radar

Receivers buried in the Nevada desert were used with the Shuttle Imaging Radar to measure microwave attenuation as a function of soil moisture in situ. Results agree closely with laboratory measureements of attenuation and suggest that penetration of tens of centimeters in desert soils is common for L-band (1.2-GHz) radar

Early Advanced LIGO binary neutron-star sky localization and parameter estimation

2015 will see the first observations of Advanced LIGO and the start of the gravitational-wave (GW) advanced-detector era. One of the most promising sources for ground-based GW detectors are binary neutron-star (BNS) coalescences. In order to use any detections for astrophysics, we must understand the capabilities of our parameter-estimation analysis. By simulating the GWs from an astrophysically motivated population of BNSs, we examine the accuracy of parameter inferences in the early advanced-detector era. We find that sky location, which is important for electromagnetic follow-up, can be determined rapidly (~5 s), but that sky areas may be hundreds of square degrees. The degeneracy between component mass and spin means there is significant uncertainty for measurements of the individual masses and spins; however, the chirp mass is well measured (typically better than 0.1%).Comment: 4 pages, 2 figures. Published in the proceedings of Amaldi 1

A pilot hole does not reduce the strains or risk of fracture to the lateral cortex during and following a medial opening wedge high tibial osteotomy in cadaveric specimens

© 2018 Bujnowski et al. Aim: It has been suggested that the use of a pilot-hole may reduce the risk of fracture to the lateral cortex. Therefore the purpose of this study was to determine the effect of a pilot hole on the strains and occurrence of fractures at the lateral cortex during the opening of a high tibial osteotomy (HTO) and post-surgery loading. Materials and Methods: A total of 14 cadaveric tibias were randomized to either a pilot hole (n = 7) or a no-hole (n = 7) condition. Lateral cortex strains were measured while the osteotomy was opened 9 mm and secured in place with a locking plate. The tibias were then subjected to an initial 800 N load that increased by 200 N every 5000 cycles, until failure or a maximum load of 2500 N. Results: There was no significant difference in the strains on the lateral cortex during HTO opening between the pilot hole and no-hole conditions. Similarly, the lateral cortex and fixation plate strains were not significantly different during cyclic loading between the two conditions. Using a pilot hole did not significantly decrease the strains experienced at the lateral cortex, nor did it reduce the risk of fracture. Conclusions: The nonsignificant differences found here most likely occurred because the pilot hole merely translated the stress concentration laterally to a parallel point on the surface of the hole