AGILE Observations of the LIGO-Virgo Gravitational-wave Events of the GWTC-1 Catalog

We present a comprehensive review of AGILE follow-up observations of the Gravitational Wave (GW) events and the unconfirmed marginal triggers reported in the first LIGO-Virgo (LV) Gravitational Wave Transient Catalog (GWTC-1). For seven GW events and 13 LV triggers, the associated 90% credible region was partially or fully accessible to the AGILE satellite at the T 0; for the remaining events, the localization region was not accessible to AGILE due to passages into the South Atlantic Anomaly, or complete Earth occultations (as in the case of GW170817). A systematic search for associated transients, performed on different timescales and on different time intervals about each event, led to the detection of no gamma-ray counterparts. We report AGILE MCAL upper limit fluences in the 400 keV–100 MeV energy range, evaluated in a time window of T 0 ± 50 s around each event, as well as AGILE GRID upper limit (UL) fluxes in the 30 MeV–50 GeV energy range, evaluated in a time frame of T 0 ± 950 s around each event. All ULs are estimated at different integration times and are evaluated within the portions of GW credible region accessible to AGILE at the different times under consideration. We also discuss the possibility of AGILE MCAL to trigger and detect a weak soft-spectrum burst such as GRB 170817A.

Robust Bayesian Inference for Set‐Identified Models

This paper reconciles the asymptotic disagreement between Bayesian and frequentist inference in set‐identified models by adopting a multiple‐prior (robust) Bayesian approach. We propose new tools for Bayesian inference in set‐identified models and show that they have a well‐defined posterior interpretation in finite samples and are asymptotically valid from the frequentist perspective. The main idea is to construct a prior class that removes the source of the disagreement: the need to specify an unrevisable prior for the structural parameter given the reduced‐form parameter. The corresponding class of posteriors can be summarized by reporting the ‘posterior lower and upper probabilities’ of a given event and/or the ‘set of posterior means’ and the associated ‘robust credible region’. We show that the set of posterior means is a consistent estimator of the true identified set and the robust credible region has the correct frequentist asymptotic coverage for the true identified set if it is convex. Otherwise, the method provides posterior inference about the convex hull of the identified set. For impulse‐response analysis in set‐identified Structural Vector Autoregressions, the new tools can be used to overcome or quantify the sensitivity of standard Bayesian inference to the choice of an unrevisable prior.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star–black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of $$10^{5}, 10^{6}, 10^{7}\mathrm {\ Mpc}^3$$ 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star–black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of $$1^{+12}_{-1}$$ 1 - 1 + 12 ($$10^{+52}_{-10}$$ 10 - 10 + 52 ) for binary neutron star mergers, of $$0^{+19}_{-0}$$ 0 - 0 + 19 ($$1^{+91}_{-1}$$ 1 - 1 + 91 ) for neutron star–black hole mergers, and $$17^{+22}_{-11}$$ 17 - 11 + 22 ($$79^{+89}_{-44}$$ 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

Conventional compared to network meta-analysis to evaluate antibiotic prophylaxis in patients with cancer and haematopoietic stem cell transplantation recipients

Our purpose was to compare conventional meta-analysis and network meta-analysis to evaluate the efficacy of different prophylactic systemic antibiotic classes in patients undergoing chemotherapy or haematopoietic stem cell transplant (HSCT). We included randomised trials if patients had cancer or were HSCT recipients and the intervention was systemic antibacterial prophylaxis. Three types of control groups were used: (1) placebo, no antibiotic and non-absorbable antibiotic separately; (2) placebo and no antibiotic combined; and (3) all three combined. These gave different network geometries. Strategies synthesised were fluoroquinolone, trimethoprim-sulfamethoxazole, cephalosporin and parenteral glycopeptide versus control groups. In total 113 trials met the eligibility criteria. Where treatment effects could be estimated with both conventional and network meta-analysis, values were generally similar. However, where events were sparse, network meta-analysis could be more precise. For example, trimethoprim-sulfamethoxazole versus placebo for infection-related mortality showed a relative risk ratio (RR) of 0.55, 95% CI (0.21 to 1.44) with conventional, and RR 0.43, 95% credible region (0.20 to 0.82) with network meta-analysis. Cephalosporin versus fluoroquinolone was comparable only indirectly using the network approach and yielded RR 0.59, 95% credible region (0.28 to 1.20) to reduce bacteraemia. Incoherence (difference between direct and indirect estimates raising concerns about network meta-analysis validity) was observed with network geometry where control groups were separated, but not where control groups were combined. In this situation, conventional and network meta-analysis yielded similar results in general. Network meta-analysis results could be more precise when events were rare. Some analysis could only be performed with the network approach. These results identify scenarios in which network meta-analysis may be advantageous.

The capability of the Australian Square Kilometre Array Pathfinder to detect prompt radio bursts from neutron star mergers

We discuss observational strategies to detect prompt bursts associated with gravitational wave (GW) events using the Australian Square Kilometre Array Pathfinder (ASKAP). Many theoretical models of binary neutron stars mergers predict that bright, prompt radio emission would accompany the merger. The detection of such prompt emission would greatly improve our knowledge of the physical conditions, environment, and location of the merger. However, searches for prompt emission are complicated by the relatively poor localisation for GW events, with the 90% credible region reaching hundreds or even thousands of square degrees. Operating in fly’s eye mode, the ASKAP field of view can reach $\sim1\,000$ deg $^2$ at $\sim$ $888\,{\rm MHz}$ . This potentially allows observers to cover most of the 90% credible region quickly enough to detect prompt emission. We use skymaps for GW170817 and GW190814 from LIGO/Virgo’s third observing run to simulate the probability of detecting prompt emission for GW events in the upcoming fourth observing run. With only alerts released after merger, we find it difficult to slew the telescope sufficiently quickly as to capture any prompt emission. However, with the addition of alerts released before merger by negative-latency pipelines, we find that it should be possible to search for nearby, bright prompt fast radio burst-like emission from GW events. Nonetheless, the rates are low: we would expect to observe $\sim$ 0.012 events during the fourth observing run, assuming that the prompt emission is emitted microseconds around the merger.

Genetic Variation and Trait Correlations for Fruit Weight, Firmness and Color Parameters in Wild Accessions of Fragaria chiloensis

Fragaria chiloensis is an herbaceous perennial undomesticated species with a high potential for sustainable fruit production in areas where drought and salinity represent a constraint on crop growth and productivity. The present study aimed to examine the genetic variability of fruit weight, firmness and color parameters (L*, a*, b*, Hue angle and Chroma) in wild-collected accessions from south-central Chile. A Bayesian analysis of genetic parameters showed that the traits under study were found to be moderately to highly heritable with estimates from the marginal posterior distributions ranging between 0.26 (firmness) and 0.67 (L*). Interestingly, Hue and Chroma had relatively high values of broad-sense heritability, with the Bayesian credible set: H 2 = 0.53–0.76 and H 2 = 0.42–0.66, respectively. A Bayesian bi-trait analysis showed a positive genetic correlation ( r ^ g = 0.65, probability of the posterior samples <0.05) between fruit weight and Hue, which agreed with the existence of two pleiotropic loci [from simple sequence repeats (SSR) markers FvH4045 and CFACT084 on linkage groups FG3A and FG2A/2B/2C] with probabilities of the posterior estimates of 0.022 and <0.001, respectively. According to the Bayesian credible region, 5 (of 12) correlation estimates were significantly different from zero. Hue and Chroma showed a high and negative genetic correlation ( r ^ g = −0.762), but no significant pleotropic locus. The results are promising and suggest that the genetic variation found among wild populations of F. chiloensis supports the idea of domesticating this crop for sustainable fruit production systems.

Calibrating general posterior credible regions

Summary Calibration of credible regions derived from under- or misspecified models is an important and challenging problem. In this paper, we introduce a scalar tuning parameter that controls the posterior distribution spread, and develop a Monte Carlo algorithm that sets this parameter so that the corresponding credible region achieves the nominal frequentist coverage probability.

BGP: Branched Gaussian processes for identifying gene-specific branching dynamics in single cell data

High-throughput single-cell gene expression experiments can be used to uncover branching dynamics in cell populations undergoing differentiation through use of pseudotime methods. We develop the branching Gaussian process (BGP), a non-parametric model that is able to identify branching dynamics for individual genes and provides an estimate of branching times for each gene with an associated credible region. We demonstrate the effectiveness of our method on both synthetic data and a published single-cell gene expression hematopoiesis study. The method requires prior information about pseudotime and global cellular branching for each cell but the probabilistic nature of the method means that it is robust to errors in these global branch labels and can be used to discover early branching genes which diverge before the inferred global cell branching. The code is open-source and available at https://github.com/ManchesterBioinference/BranchedGP.