A5103079292- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Thin-Film Transistor Technologies
- Cosmology and Gravitation Theories
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- High-pressure geophysics and materials
- Semiconductor materials and devices
- Earthquake Detection and Analysis
- Astrophysics and Cosmic Phenomena
- Ionosphere and magnetosphere dynamics
- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Cryospheric studies and observations
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Geomagnetism and Paleomagnetism Studies
- Radio Astronomy Observations and Technology
- Seismology and Earthquake Studies
- Planetary Science and Exploration
- Atomic and Subatomic Physics Research
- Dark Matter and Cosmic Phenomena
- Geophysical Methods and Applications
European Organization for Nuclear Research
2025
University of Portsmouth
2024-2025
University of Glasgow
2018-2024
Ames Research Center
2018
Georgia Institute of Technology
2018
Schlumberger (British Virgin Islands)
2014-2017
Columbia University
2014
Delaware State University
2014
Max Planck Institute for Extraterrestrial Physics
2014
Newcastle University
2002
ABSTRACT Gravitational waves provide a unique tool for observational astronomy. While the first LIGO–Virgo catalogue of gravitational-wave transients (GWTC-1) contains 11 signals from black hole and neutron star binaries, number observations is increasing rapidly as detector sensitivity improves. To extract information observed signals, it imperative to have fast, flexible, scalable inference techniques. In previous paper, we introduced bilby: modular user-friendly Bayesian library adapted...
We report on the construction of a deep convolutional neural network that can reproduce sensitivity matched-filtering search for binary black hole gravitational-wave signals. The standard method detection well-modeled transient signals is matched filtering. use only whitened time series measured strain as an input, and we train test simulated in synthetic Gaussian noise representative Advanced LIGO sensitivity. show our classify signal from with performance emulates match filtering applied...
We present a novel method for sampling iso-likelihood contours in nested using type of machine learning algorithm known as normalizing flows and incorporate it into our sampler nessai. nessai is designed problems where computing the likelihood computationally expensive therefore cost training flow offset by overall reduction number evaluations. validate on 128 simulated gravitational wave signals from compact binary coalescence show that produces unbiased estimates system parameters....
Abstract We present an improved version of the nested sampling algorithm nessai in which core is modified to use importance weights. In algorithm, samples are drawn from a mixture normalising flows and requirement for be independently identically distributed (i.i.d.) according prior relaxed. Furthermore, it allows added any order, likelihood constraint, evidence updated with batches samples. call i-nessai . first validate using analytic likelihoods known Bayesian evidences show that...
Fourier transform infrared spectroscopy has been used to study the behavior of bonded hydrogen and deuterium in hydrogenated amorphous silicon nitride films [a-Si:N:H(D)] that were deposited by remote plasma-enhanced chemical vapor deposition (RPECVD) had subjected rapid thermal annealing (RTA) from 400 1200 °C after film deposition. The amount its distribution between Si–H SiN–H bonding groups is correlated ratio (R) source gases: NH3 SiH4. Chemical reaction pathways are proposed account...
We demonstrate an end-to-end technique for observing and characterizing massive black hole binary signals before they merge with the LISA space-based gravitational-wave observatory. Our method uses a zero-latency whitening filter, originally designed rapidly compact mergers in ground-based observatories, to be able observe no additional latency due filter length. show that minimal computational cost, we are reliably as early 14 days premerger long signal has accrued signal-to-noise ratio of...
The 5,575‐km 2 Academy of Sciences Ice Cap is the largest in Russian Arctic. A 100‐MHz airborne radar, digital Landsat imagery, and satellite synthetic aperture radar (SAR) interferometry are used to investigate its form flow, including proportion mass lost through iceberg calving. ice cap was covered by a 10‐km‐spaced grid flight paths, central portion at 5‐km intervals: total 1,657 km data. Digital elevation models (DEMs) surface elevation, thickness, bed data sets were produced (cell size...
APOL1 risk variants are associated with increased of kidney disease in patients African ancestry, but not all individuals the high-risk genotype develop disease. As gene expression correlates closely degree cell injury both and animal models, mechanisms regulating may be critical determinants allele penetrance. The messenger RNA includes Alu elements at 3′ untranslated region that can form a double-stranded structure (Alu-dsRNA) susceptible to posttranscriptional adenosine deaminase acting...
Troughs in the latitudinal distribution of electron density are a well‐known feature ionosphere from subauroral to polar latitudes. The location and depth trough minimum, width feature, horizontal gradients associated with walls all quantities interest or concern practical applications radio systems involving ionosphere. In practice, precise characteristics trough‐like structures have been difficult monitor using ground‐based methods. Ionospheric tomography represents new development that is...
Abstract We present a novel fully Bayesian analysis to constrain short gamma-ray burst (sGRB) jet structures associated with cocoon, wide-angle, and simple top-hat models, as well the binary neutron star (BNS) merger rate. These constraints are made given distance inclination information from GW170817, observed flux of GRB 170817A, rate sGRBs detected by Swift, inferred LIGO’s first second observing runs. A separate is conducted where fitted sGRB luminosity function included provide further...
Previous studies have reported the existence of two counter-rotating stellar discs in early-type spiral galaxy NGC 7217. We obtained high-resolution optical spectroscopic data (R ≈ 9000) with new fibre-based Integral Field Unit instrument VIRUS-W at 2.7-m telescope McDonald Observatory Texas. Our analysis confirms components. However, we find them to be corotating. The first component is more luminous (≈77 per cent total light), has higher velocity dispersion (≈170 km s−1) and rotates...
Abstract We introduce the use of conditional generative adversarial networks (CGANs) for generalised gravitational wave (GW) burst generation in time domain. Generative are machine learning models that produce new data based on features training set. condition network five classes time-series signals often used to characterise GW searches: sine-Gaussian, ringdown, white noise burst, Gaussian pulse and binary black hole merger. show model can replicate these standard signal and, addition,...
Abstract The discovery of the optical counterpart, along with gravitational waves (GWs) from GW170817, first binary neutron star merger has opened up a new era for multimessenger astrophysics. Combining GW data also known as AT 2017gfo and classified kilonova, revealed nature compact merging systems by extracting enriched information about total mass, mass ratio, system geometry, equation state. Even though detection kilonovae brought revolution in domain astronomy, there been only one...
This paper compares the performance of three different reconstruction algorithms used for tomographic imaging ionosphere. The test cases chosen make use experimental electron content observations obtained from a meridional chain receivers in Scandinavia at times when European incoherent scatter radar facility provided independent measurements density verification reconstructions. examples include ionospheres with layers peaking both anomalously high and very low altitudes, addition to smooth...
A study was conducted to quantify the amount of time spent by grazing cattle near or in water locations (wetlands, ditches, and troughs) across seasons a cow-calf production ranch south Florida. Prolonged hot summers these regions can cause physiological heat stress drive them into water-filled ditches wetlands order cool down. Because numerous ranches region, it is perceived that this activity contributing towards phosphorus loading receiving body, Lake Okeechobee. Cattle position data...
Abstract. Tomographic imaging provides a powerful technique for obtaining images of the spatial distribution ionospheric electron density at polar latitudes. The method, which involves monitoring radio transmissions from Navy Navigation Satellite System meridional chain ground receivers, has particular potential complementing temporal measurements by other observing techniques such as EISCAT incoherent-scatter radar facility. reconstructions are presented here two-week campaign in November...
The first direct detection of gravitational waves from binary neutron stars on the 17th August, 2017, (GW170817) heralded arrival a new messenger for probing star astrophysics and provided constraints equation state wave observations. Significant computational effort was expended to obtain these results therefore, as observations coalescence become more routine in coming observing runs, there is need improve analysis speed flexibility. Here, we present rapid approach inferring based...
Abstract. This paper highlights the important role played by EISCAT radar for verification in development of tomographic techniques to produce images ionospheric electron density. A brief review is given some stages application reconstruction ionosphere. Results are presented illustrate effectiveness method imaging structures at high latitudes. In addition, results include first image ionosphere a region extending from mid-latitudes over mainland Scandinavia latitudes above Svalbard.
Electronically active defects in hydrogenated amorphous silicon thin films, deposited by the conventional glow discharge process temperature range between about 225 and 325 °C with ∼10–15 at. % hydrogen, undergo a thermally activated relaxation during film deposition. We determine kinetics of this films similar hydrogen concentrations reactive magnetron sputtering at substrate ∼40 °C, annealed temperatures greater than 150 °C. present quantitative relationship time, deposition and/or...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSecondary structure of a pair fibronectin type 1 modules by two-dimensional nuclear magnetic resonanceMichael J. Williams, Isabelle Phan, Martin Baron, Paul C. Driscoll, and Iain D. CampbellCite this: Biochemistry 1993, 32, 29, 7388–7395Publication Date (Print):July 1, 1993Publication History Published online1 May 2002Published inissue July 1993https://pubs.acs.org/doi/10.1021/bi00080a008https://doi.org/10.1021/bi00080a008research-articleACS...
We have used remote plasma-enhanced chemical vapor deposition (remote PECVD) to deposit both intrinsic and doped μc-Si thin films at temperatures between 100 400 °C. Two different pathways been studied: (i) plasma excitation of He/H2 mixtures with downstream injection silane, SiH4, the dopant gases phosphine, PH3 or diborane, B2H6; (ii) He, SiH4 H2, as well gases. observed that second pathway, readily promotes nucleation on a number substrate materials, including crystalline Si, fused...