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The mergers of binary compact objects such as neutron stars and black holes are of central interest to several areas of astrophysics, including as the progenitors of gamma-ray bursts (GRBs) 1 , sources of high-frequency gravitational waves (GWs) 2 and likely production sites for heavy-element nucleosynthesis by means of rapid neutron capture (the r -process) 3 . Here we present observations of the exceptionally bright GRB 230307A. We show that GRB 230307A belongs to the class of long-duration GRBs associated with compact object mergers 4 – 6 and contains a kilonova similar to AT2017gfo, associated with the GW merger GW170817 (refs.  7 – 12 ). We obtained James Webb Space Telescope (JWST) mid-infrared imaging and spectroscopy 29 and 61 days after the burst. The spectroscopy shows an emission line at 2.15 microns, which we interpret as tellurium (atomic mass A  = 130) and a very red source, emitting most of its light in the mid-infrared owing to the production of lanthanides. These observations demonstrate that nucleosynthesis in GRBs can create r -process elements across a broad atomic mass range and play a central role in heavy-element nucleosynthesis across the Universe. Observations from the JWST of the second brightest GRB ever detected, GRB 230307A, indicate that it belongs to the class of long-duration GRBs resulting from compact object mergers, with the decay of lanthanides powering the longlasting optical and infrared emission.

Smoking-related destructive lung diseases such as chronic obstructive pulmonary disease (COPD) and emphysema are a major cause of morbidity and mortality worldwide. The immediate cause of emphysema is the obliteration of alveoli that are key functional units of the lungs where gas exchange takes place. Alveolar generation/regeneration under normal and pathologic conditions is a poorly understood process, but may hold the key to treatment of human emphysema. We used suppression subtractive hybridization to identify genes that may control alveolar generation during periods of pre- and postnatal active alveolar development. P311, a putative neuronal protein originally identified for its high expression in late-stage embryonic brain, was highly differentially expressed during periods of active distal lung morphogenesis. Quantitative real-time RT-PCR showed that the expression of P311 is developmentally regulated, with peak levels occurring during saccular and alveolar formation. Intriguingly, P311 gene expression was significantly decreased in lungs of individuals with emphysema compared with control subjects. Consistent with a role for this gene in alveolar formation, inhibition of alveolization by dexamethasone treatment in vivo resulted in decreased expression of P311. Together our data suggest that P311 expression is tightly regulated during the critical periods of alveolar formation, and that under pathologic conditions, its relative absence may contribute to failure of alveolar regeneration and lead to the development of human emphysema.

The deaths of massive stars are sometimes accompanied by the launch of highly relativistic and collimated jets. If the jet is pointed towards Earth, we observe a ‘prompt’ gamma-ray burst due to internal shocks or magnetic reconnection events within the jet, followed by a long-lived broadband synchrotron afterglow as the jet interacts with the circumburst material. While there is solid observational evidence that emission from multiple shocks contributes to the afterglow signature, detailed studies of the reverse shock, which travels back into the explosion ejecta, are hampered by a lack of early-time observations, particularly in the radio band. We present rapid follow-up radio observations of the exceptionally bright gamma-ray burst GRB 221009A that reveal in detail, both temporally and in frequency space, an optically thick rising component from the reverse shock. From this, we are able to constrain the size, Lorentz factor and internal energy of the outflow while providing accurate predictions for the location of the peak frequency of the reverse shock in the first few hours after the burst. These observations challenge standard gamma-ray burst models describing reverse shock emission.Early-time multi-frequency radio observations of the exceptionally bright GRB 221009A show the detailed evolution of a reverse shock formed within the jet that was launched as the result of a stellar explosion.

Radio transient searches using traditional variability metrics struggle to recover sources whose evolution timescale is significantly longer than the survey cadence. Motivated by the recent observations of slowly evolving radio afterglows at gigahertz frequency, we present the results of a search for radio variables and transients using an alternative matched-filter approach. We designed our matched-filter to recover sources with radio light curves that have a high-significance fit to power-law and smoothly broken power-law functions; light curves following these functions are characteristic of synchrotron transients, including \"orphan\" gamma-ray burst afterglows, which were the primary targets of our search. Applying this matched-filter approach to data from Variables and Slow Transients Pilot Survey conducted using the Australian SKA Pathfinder, we produced five candidates in our search. Subsequent Australia Telescope Compact Array observations and analysis revealed that: one is likely a synchrotron transient; one is likely a flaring active galactic nucleus, exhibiting a flat-to-steep spectral transition over \\(4\\,\\)months; one is associated with a starburst galaxy, with the radio emission originating from either star formation or an underlying slowly evolving transient; and the remaining two are likely extrinsic variables caused by interstellar scintillation. The synchrotron transient, VAST J175036.1\\(-\\)181454, has a multi-frequency light curve, peak spectral luminosity, and volumetric rate that is consistent with both an off-axis afterglow and an off-axis tidal disruption event; interpreted as an off-axis afterglow would imply an average inverse beaming factor \\(\\langle f^{-1}_{\\text{b}} \\rangle = 860^{+1980}_{-710}\\), or equivalently, an average jet opening angle of \\(\\langle \\theta_{\\textrm{j}} \\rangle = 3^{+4}_{-1}\\,\\)deg.

We present a method for identifying radio stellar sources using their proper-motion. We demonstrate this method using the FIRST, VLASS, RACS-low and RACS-mid radio surveys, and astrometric information from Gaia Data Release 3. We find eight stellar radio sources using this method, two of which have not previously been identified in the literature as radio stars. We determine that this method probes distances of ~90pc when we use FIRST and RACS-mid, and ~250pc when we use FIRST and VLASS. We investigate the time baselines required by current and future radio sky surveys to detect the eight sources we found, with the SKA (6.7 GHz) requiring <3 years between observations to find all eight sources. We also identify nine previously known and 43 candidate variable radio stellar sources that are detected in FIRST (1.4 GHz) but are not detected in RACS-mid (1.37 GHz). This shows that many stellar radio sources are variable, and that surveys with multiple epochs can detect a more complete sample of stellar radio sources.

We present a systematic search for radio counterparts of novae using the Australian Square Kilometer Array Pathfinder (ASKAP). Our search used the Rapid ASKAP Continuum Survey, which covered the entire sky south of declination \\(+41^{\\circ}\\) (\\(\\sim34,000\\) square degrees) at a central frequency of 887.5 MHz, the Variables and Slow Transients Pilot Survey, which covered \\(\\sim5,000\\) square degrees per epoch (887.5 MHz), and other ASKAP pilot surveys, which covered \\(\\sim200-2000\\) square degrees with 2-12 hour integration times. We crossmatched radio sources found in these surveys over a two-year period, from April 2019 to August 2021, with 440 previously identified optical novae, and found radio counterparts for four novae: V5668 Sgr, V1369 Cen, YZ Ret, and RR Tel. Follow-up observations with the Australian Telescope Compact Array confirm the ejecta thinning across all observed bands with spectral analysis indicative of synchrotron emission in V1369 Cen and YZ Ret. Our light-curve fit with the Hubble Flow model yields a value of \\(1.65\\pm 0.17 \\times 10^{-4} \\rm \\:M_\\odot\\) for the mass ejected in V1369 Cen. We also derive a peak surface brightness temperature of \\(250\\pm80\\) K for YZ Ret. Using Hubble Flow model simulated radio lightcurves for novae, we demonstrate that with a 5\\(\\sigma\\) sensitivity limit of 1.5 mJy in 15-min survey observations, we can detect radio emission up to a distance of 4 kpc if ejecta mass is in the range \\(10^{-3}\\rm \\:M_\\odot\\), and upto 1 kpc if ejecta mass is in the range \\(10^{-5}-10^{-3}\\rm \\:M_\\odot\\). Our study highlights ASKAP's ability to contribute to future radio observations for novae within a distance of 1 kpc hosted on white dwarfs with masses \\(0.4-1.25\\:\\rm M_\\odot\\) , and within a distance of 4 kpc hosted on white dwarfs with masses \\(0.4-1.0\\:\\rm M_\\odot\\).

We present the results of a radio transient and polarisation survey towards the Galactic Centre, conducted as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients pilot survey. The survey region consisted of five fields covering \\(\\sim265\\,{\\rm deg}^2\\) (\\(350^\\circ\\lesssim l\\lesssim10^\\circ\\), \\(\\vert b\\vert \\lesssim 10^\\circ\\)). Each field was observed for 12\\,minutes, with between 7 and 9 repeats on cadences of between one day and four months. We detected eight highly variable sources and seven highly circularly-polarised sources (14 unique sources in total). Seven of these sources are known pulsars including the rotating radio transient PSR~J1739--2521 and the eclipsing pulsar PSR~J1723--2837. One of them is a low mass X-ray binary, 4U 1758--25. Three of them are coincident with optical or infrared sources and are likely to be stars. The remaining three may be related to the class of Galactic Centre Radio Transients (including a highly likely one, VAST~J173608.2--321634, that has been reported previously), although this class is not yet understood. In the coming years, we expect to detect \\(\\sim\\)40 bursts from this kind of source with the proposed four-year VAST survey if the distribution of the source is isotropic over the Galactic fields.

The nucleobase/ascorbate transporters (NAT) are responsible for the uptake of nucleobases in all kingdoms of life, and for transportation of ascorbic acid (vitamin C) in humans. Nucleobase analogues are often used as antimetabolites in the treatment of a range of diseases. A detailed understanding of nucleobase transport will increase understanding of the mechanism of action of these important proteins and facilitate design of drugs with enhanced efficacy and specificity. Owing to the extensive genetic and biochemical analysis, UapA from A. nidulans is the best studied example of the NAT family. The aim of this project was to produce pure and stable UapA from A. nidulans for structural studies by X-­‐ray crystallography. In this study, it was possible to express wild type UapA in S. cerevisiae as a GFP fusion to 1.91 mg/L. Following purification, the protein was extremely unstable, degrading almost completely after 48 hours at 4°C. A number of single point mutants previously shown to exhibit reduced transport activity but correct targeting to the membrane were generated in an attempt to increase UapA stability. hFSEC and FSEC allowed successful identification of the thermostable mutant G411V, with preserved xanthine binding. G411V expressed well as a GFP fusion and was purified to homogeneity with a yield of 2.8 mg from 10 L culture. The purified protein was stable at 4°C for at least 2 days. Removal of the 11 amino acid residues at the N terminus, G411V12-­‐574, improved purification yield to 4.2 mg from 10 L culture and resulted in protein that was stable at 4°C for at least 6 days. Optimised crystals of this construct currently diffract to 7.16 Å resolution. Boron (B) toxicity and deficiency in plants are worldwide agricultural problems. Understanding the mechanism of boron homeostasis in plant will provide route for the design of crops tolerant to soils with suboptimal B concentrations. We aimed to solve the structure of a boric acid transporter from A. thaliana. Preliminary crystals diffracted to 7.6 Å. Significant optimisation screening including the use of structure specific antibodies failed to improve the diffraction limit. A breakthrough came with the use of a novel type of amphiphile, undecyl-­‐MNG, which significantly improved the diffraction limit to 5.0 Å. Crystal optimisation is underway to further improve the resolution.

We present a multi-wavelength analysis, from the radio to the X-ray band, of the redshift \\(z=6.44\\) VIK J2318\\(-\\)31 radio-loud (RL) quasi stellar object (QSO), one of the most distant currently known in this class. The work is based on newly obtained (uGMRT, ATCA, Chandra) as well as archival (GNIRS and X-Shooter) dedicated observations that have not been published yet. Based on the observed X-ray and radio emission, its relativistic jets are likely young and misaligned from our line of sight. Moreover, we can confirm, with simultaneous observations, the presence of a turnover in the radio spectrum at \\(\\nu_{\\rm peak} \\sim 650\\) MHz which is unlikely to be associated with self-synchrotron absorption. From the NIR spectrum we derived the mass of the central black hole, M\\(_{\\rm BH}=8.1^{+6.8}_{-5.6} \\times 10^8 {\\rm M_{\\odot}}\\), and the Eddington ratio, \\(\\lambda_{\\rm EDD} = 0.8^{+0.8}_{-0.6}\\), using broad emission lines as well as an accretion disc model fit to the continuum emission. Given the high accretion rate, the presence of a \\(\\sim\\)8\\(\\times\\)10\\(^8\\) M\\(_\\odot\\) black hole at \\(z=6.44\\) can be explained by a seed black hole (\\(\\sim\\)10\\(^{4}\\) M\\(_\\odot\\)) that formed at \\(z\\sim25\\), assuming a radiative efficiency \\(\\eta_{\\rm d}\\sim0.1\\). However, by assuming \\(\\eta_{\\rm d}\\sim0.3\\), as expected for jetted systems, the mass observed would challenge current theoretical models of black hole formation.

We present a search for radio afterglows from long gamma-ray bursts using the Australian Square Kilometre Array Pathfinder (ASKAP). Our search used the Rapid ASKAP Continuum Survey, covering the entire celestial sphere south of declination \\(+41^\\circ\\), and three epochs of the Variables and Slow Transients Pilot Survey (Phase 1), covering \\(\\sim 5,000\\) square degrees per epoch. The observations we used from these surveys spanned a nine-month period from 2019 April 21 to 2020 January 11. We crossmatched radio sources found in these surveys with 779 well-localised (to \\(\\leq 15''\\)) long gamma-ray bursts occurring after 2004 and determined whether the associations were more likely afterglow- or host-related through the analysis of optical images. In our search, we detected one radio afterglow candidate associated with GRB 171205A, a local low-luminosity gamma-ray burst with a supernova counterpart SN 2017iuk, in an ASKAP observation 511 days post-burst. We confirmed this detection with further observations of the radio afterglow using the Australia Telescope Compact Array at 859 days and 884 days post-burst. Combining this data with archival data from early-time radio observations, we showed the evolution of the radio spectral energy distribution alone could reveal clear signatures of a wind-like circumburst medium for the burst. Finally, we derived semi-analytical estimates for the microphysical shock parameters of the burst: electron power-law index \\(p = 2.84\\), normalised wind-density parameter \\(A_* = 3\\), fractional energy in electrons \\(\\epsilon_{e} = 0.3\\), and fractional energy in magnetic fields \\(\\epsilon_{B} = 0.0002\\).