Detector Description and Performance for the First Coincidence Observations between LIGO and GEO

For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial change

Technology-enabled CONTACT tracing in care homes in the COVID-19 pandemic: the CONTACT non-randomised mixed-methods feasibility study

Background Coronavirus disease 2019 devastated lives in care homes for older people, where residents faced higher mortality risks than the general population. Infection prevention and control decisions were critical to protect these vulnerable residents. Infection prevention and control measures like ‘lockdowns’ had their own risks, such as social isolation, alongside assumed benefits. A key non-pharmaceutical intervention for managing infections is contact tracing. Traditional contact tracing, which relies on recalling contacts, is not feasible in care homes where approximately 70% of residents have cognitive impairments. The CONtact TrAcing in Care homes using digital Technology intervention introduces Bluetooth-enabled wearable devices for automated contact tracing. We provided structured reports (scheduled regularly and in reaction to positive COVID-19 cases) on contact patterns to homes to support better-informed infection prevention and control decisions and potentially reduce blanket restrictive measures. We also partnered with the PROTECT COVID-19 research team to examine air quality in two of our homes. Methods CONTACT was a non-randomised mixed-method feasibility study in four English care homes. Recruitment was via care home research networks, with individual consent. Data collection included routine device data, case report forms, qualitative interviews, field observations of care home activity and an adapted Normalisation Measure Development questionnaire survey to explore implementation using normalisation process theory. Quantitative data were analysed using descriptive statistical methods, and qualitative data were thematically analysed using normalisation process theory. Intervention and study delivery were evaluated against predefined progression criteria. Results Of 156 eligible residents, 105 agreed to wear a device, with 102 (97%) starting the intervention. Of 225 eligible staff, 82.4% (n = 178) participated. Over 2 months, device loss and battery failure were significant: residents lost 11% of devices, with half replaced. Staff lost fewer devices, just 6.5%, but < 10% were replaced. Fob wearables needed more battery changes than card-type devices (15% vs. 0%). Homes variably understood structured and reactive feedback but were unlikely to act on it. Researcher support for interpreting reports was valued. Homes found information useful when it confirmed rather than challenged preconceived contact patterns. Staff privacy concerns were a barrier to adoption. Study procedures added to existing work, making participation burdensome. The perceived burden of participation, amplified by the pandemic context, outweighed the benefits. CONTACT did not meet its quantitative or qualitative progression criteria. Limitations Researchers had to pragmatically adapt procedures, resulting in suboptimal implementation choices from an implementation science perspective. Future research should co-design interventions with homes, focusing on implementation and wearability as much as technical effectiveness. Conclusion A definitive trial of CONTACT was not feasible or acceptable to care homes, partly due to the shifting pandemic context and demands on homes. With more effective implementation, Bluetooth-enabled wearable systems as part of ‘Internet of Things’ in homes could be used to: (1) better understand airborne transmission risks, ventilation and air quality and (2) make important relational aspects of care quality and residents’ quality of life more transparent. Future work We will continue to explore the possibilities of Bluetooth-enabled wearables for modelling social networks, movement, infection risks and quality in care homes with academic and care partners

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2 Ma-1.0 Ma. We use the null result to constrain the binary merger rate of (0.2 M, 0.2 M) binaries to be less than 3.7×105 Gpc-3 yr-1 and the binary merger rate of (1.0 M, 1.0 M) binaries to be less than 5.2×103 Gpc-3 yr-1. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2 M black holes to account for less than 16% of the dark matter density and a population of merging 1.0 M black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries. © 2019 American Physical Society

Directional Limits on Persistent Gravitational Waves from Advanced LIGO's First Observing Run

We employ gravitational-wave radiometry to map the stochastic gravitational wave background expected from a variety of contributing mechanisms and test the assumption of isotropy using data from the Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. We also search for persistent gravitational waves from point sources with only minimal assumptions over the 20-1726 Hz frequency band. Finding no evidence of gravitational waves from either point sources or a stochastic background, we set limits at 90% confidence. For broadband point sources, we report upper limits on the gravitational wave energy flux per unit frequency in the range Fα,Θ(f)<(0.1-56)×10-8 erg cm-2 s-1 Hz-1(f/25 Hz)α-1 depending on the sky location Θ and the spectral power index α. For extended sources, we report upper limits on the fractional gravitational wave energy density required to close the Universe of Ω(f,Θ)<(0.39-7.6)×10-8 sr-1(f/25 Hz)α depending on Θ and α. Directed searches for narrowband gravitational waves from astrophysically interesting objects (Scorpius X-1, Supernova 1987 A, and the Galactic Center) yield median frequency-dependent limits on strain amplitude of h0<(6.7,5.5, and 7.0)×10-25, respectively, at the most sensitive detector frequencies between 130-175 Hz. This represents a mean improvement of a factor of 2 across the band compared to previous searches of this kind for these sky locations, considering the different quantities of strain constrained in each case. © 2017 Published by the American Physical Society