Observations of Galactic supernova remnants (SNRs) are crucial to understanding supernova explosion mechanisms and their impact on our Galaxy’s evolution. SNRs are usually identified by searching for extended, circular structures in all-sky surveys. However, the resolution and sensitivity of any given survey results in selection biases related to the brightness and angular scale of a subset of the total SNR population. As a result, we have only identified 1/3 of the expected number of SNRs in our Galaxy. We used data collected by the Murchison Widefield Array (MWA) to perform a visual search for SNR candidates over 285° < l < 70° and |b| < 16°. We then used the Widefield Infrared Survey Explorer to eliminate likely HII regions from our SNR candidate sample. By exploiting the resolution and sensitivity of MWA data, we have successfully detected 10 new candidates using our proposed method. In addition, our method has also enabled us to detect and verify 10 previously known but unconfirmed candidates. The 20 SNR candidates described in the paper will increase the known SNR population in the Galaxy by 7%.

A Bayesian nonparametric model is introduced for score equating. It is applicable to all major equating designs, and has advantages over previous equating models. Unlike the previous models, the Bayesian model accounts for positive dependence between distributions of scores from two tests. The Bayesian model and the previous equating models are compared through the analysis of data sets famous in the equating literature. Also, the classical percentile-rank, linear, and mean equating models are each proven to be a special case of a Bayesian model under a highly-informative choice of prior distribution.

Three kaolinite reference samples identified as KGa-1, KGa-1b, and KGa-2 from the Source Clays Repository of The Clay Mineral Society (CMS) are used widely in diverse fields, but the defect structures have still not been determined with certainty. To solve this problem, powder diffraction patterns of the KGa-1, KGa-1b, and KGa-2 samples were modeled. In a kaolinite layer among three symmetrically independent octahedral sites named as A, B, and C and separated from each other by b/3 along the b parameter, the A and B sites are occupied by Al cations, whereas, the C sites located along the long diagonal of the oblique kaolinite unit cell are vacant. The layer displacement vectors t1 and t2 are related by a pseudo-mirror plane from defect-free 1Tc kaolinite enantiomorphs, whereas, the random interstratification within individual kaolinite crystallites creates right-hand and left-hand layer sub-sequences producing structural disorder. A third layer displacement vector, t0, located along the long diagonal of the oblique layer unit cell that contains the vacant octahedral site and coincides with the layer pseudo-mirror plane may exist. Thus, a structural model should be defined by the probability of t1, t2, and t0 layer displacement translations Wt1, Wt2, and Wt0, respectively, determined by simulated experimental X-ray diffraction (XRD) patterns. X-ray diffraction patterns were calculated for structures with a given content of randomly interstratified displacement vectors, and other XRD patterns were calculated for a physical mixture of crystallites having contrasting structural order with only C-vacant layers. The samples differ from each other by the content of high- and low-ordered phases referred to as HOK and LOK. The HOK phase has an almost defect-free structure in which 97% of the layer pairs are related by just the layer displacement vector t1 and only 3% of the layer pairs form the enantiomorphic fragments. In contrast, the LOK phases in the KGa-1, KGa-1b, and KGa-2 samples differ from HOK phases by the occurrence probabilities for the t1, t2, and t0 layer displacements. In addition, the LOK phases contain stacking faults that displace adjacent layers in arbitrary lengths and directions. Low XRD profile factors (Rp = 8-11%) support the defect structure models. Additional structural defects and previously published models are discussed.

We describe the design, validation, and commissioning of a new correlator termed ‘MWAX’ for the Murchison Widefield Array (MWA) low-frequency radio telescope. MWAX replaces an earlier generation MWA correlator, extending correlation capabilities and providing greater flexibility, scalability, and maintainability. MWAX is designed to exploit current and future Phase II/III upgrades to MWA infrastructure, most notably the simultaneous correlation of all 256 of the MWA’s antenna tiles (and potentially more in future). MWAX is a fully software-programmable correlator based around an ethernet multicast architecture. At its core is a cluster of 24 high-performance GPU-enabled commercial-off-the-shelf compute servers that together process in real-time up to 24 coarse channels of 1.28 MHz bandwidth each. The system is highly flexible and scalable in terms of the number of antenna tiles and number of coarse channels to be correlated, and it offers a wide range of frequency/time resolution combinations to users. We conclude with a roadmap of future enhancements and extensions that we anticipate will be progressively rolled out over time.

In Paper I, we presented an overview of the Southern-sky MWA Rapid Two-metre (SMART) survey, including the survey design and search pipeline. While the combination of MWA’s large field-of-view and the voltage capture system brings a survey speed of ${\sim} 450\, {\textrm{deg}}^{2}\,\textrm{h}^{-1}$, the progression of the survey relies on the availability of compact configuration of the Phase II array. Over the past few years, by taking advantage of multiple windows of opportunity when the compact configuration was available, we have advanced the survey to 75% of the planned sky coverage. To date, about 10% of the data collected thus far have been processed for a first-pass search, where 10 min of observation is processed for dispersion measures out to 250 ${\textrm{pc cm}}^{-3}$, to realise a shallow survey that is largely sensitive to long-period pulsars. The ongoing analysis has led to two new pulsar discoveries, as well as an independent discovery and a rediscovery of a previously incorrectly characterised pulsar, all from ${\sim} 3\% $ of the data for which candidate scrutiny is completed. In this sequel to Paper I, we describe the strategies for further detailed follow-up including improved sky localisation and convergence to timing solution, and illustrate them using example pulsar discoveries. The processing has also led to re-detection of 120 pulsars in the SMART observing band, bringing the total number of pulsars detected to date with the MWA to 180, and these are used to assess the search sensitivity of current processing pipelines. The planned second-pass (deep survey) processing is expected to yield a three-fold increase in sensitivity for long-period pulsars, and a substantial improvement to millisecond pulsars by adopting optimal de-dispersion plans. The SMART survey will complement the highly successful Parkes High Time Resolution Universe survey at 1.2–1.5 GHz, and inform future large survey efforts such as those planned with the low-frequency Square Kilometre Array (SKA-Low).

We present an overview of the Southern-sky MWA Rapid Two-metre (SMART) pulsar survey that exploits the Murchison Widefield Array’s large field of view and voltage-capture system to survey the sky south of 30$^{\circ}$ in declination for pulsars and fast transients in the 140–170 MHz band. The survey is enabled by the advent of the Phase II MWA’s compact configuration, which offers an enormous efficiency in beam-forming and processing costs, thereby making an all-sky survey of this magnitude tractable with the MWA. Even with the long dwell times employed for the survey (4800 s), data collection can be completed in $<$100 h of telescope time, while still retaining the ability to reach a limiting sensitivity of $\sim$2–3 mJy (at 150 MHz, near zenith), which is effectively 3–5 times deeper than the previous-generation low-frequency southern-sky pulsar survey, completed in the 1990s. Each observation is processed to generate $\sim$5000–8000 tied-array beams that tessellate the full $\sim 610\, {\textrm{deg}^{2}}$ field of view (at 155 MHz), which are then processed to search for pulsars. The voltage-capture recording of the survey also allows a multitude of post hoc processing options including the reprocessing of data for higher time resolution and even exploring image-based techniques for pulsar candidate identification. Due to the substantial computational cost in pulsar searches at low frequencies, the survey data processing is undertaken in multiple passes: in the first pass, a shallow survey is performed, where 10 min of each observation is processed, reaching about one-third of the full-search sensitivity. Here we present the system overview including details of ongoing processing and initial results. Further details including first pulsar discoveries and a census of low-frequency detections are presented in a companion paper. Future plans include deeper searches to reach the full sensitivity and acceleration searches to target binary and millisecond pulsars. Our simulation analysis forecasts $\sim$300 new pulsars upon the completion of full processing. The SMART survey will also generate a complete digital record of the low-frequency sky, which will serve as a valuable reference for future pulsar searches planned with the low-frequency Square Kilometre Array.

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.

Mortality rates are often used in population-level animal welfare assessments because they are assumed to reflect rates of disease or injury and other problems likely to cause poor welfare. High mortality is thus assumed to correlate with factors likely to cause negative affective states. Here, we argue that negative affective states are also related to mortality rates more directly, via causal rather than merely correlational routes. In humans, negative affective states predict elevated morbidity and mortality rates as well as decreased longevity, while self-reported happiness does the opposite. This review investigates whether mortality rates and longevity can thus be used to make inferences regarding past affective states in animals. The proposed mechanism is that chronic stressors cause negative affective states and thence harmful physiological consequences through continual activation of the hypothalamic-pituitary-adrenal and sympathetic-adreno-medullary axes, which in turn can lead to increased mortality. The convergent validity of mortality as an indicator of past negative affect is demonstrated via examples of how stressors such as bereavement in humans and social isolation in social non-human species cause negative affective states, and then increase the morbidity of potentially lethal conditions such as cardiovascular disease, cancer and HIV/AIDS, ultimately leading to increased mortality and reduced longevity in both humans and animals. The potential drawbacks of using mortality rates to infer animal welfare are also discussed, including its low sensitivity and the multiplicity of factors unrelated to affective states that can influence mortality rates. However, providing these issues are accounted for, it is suggested that this indicator has value in welfare assessment, and is especially well suited for cases where animals are allowed to live out their natural lifespans, such as tends to be the case with zoo and companion animals.

Stereotypic behaviours (SBs) are linked with behavioural inflexibility and resemble symptoms of autism, suggesting that stereotypic animals could have autistic-like social impairments. SBs are also common in caged mice. We therefore hypothesised relationships between stereotypic and social behaviours, predicting that highly stereotypic mice would give/receive more agonism and be less effective in social learning tasks. Experiment One used C57BL/6 and DBA/2 mice in non-enriched or enriched housing (15 cages each); Experiment Two, more cages (six non-enriched, 44 enriched) plus a third strain (BALB/c). Across both experiments, enrichment reduced SB and agonism (aggression, plus ‘displacements’ where one mouse supplants another at a resource). These effects appeared related: housing effects on agonism became negligible when SB was statistically controlled for, and, at least in enriched cages, SB covaried with receiving aggression. In Experiment Three, 20 DBAs varying in SB from Experiment Two acted as demonstrators in a ‘social transmission of food preferences’ task. They were fed a novel flavour (shatavari powder), then each mingled with a familiar but flavour-naïve C57 observer. Observers were subsequently offered two novel flavours: shatavari or marjoram. Those spontaneously choosing more shatavari (n = 10) tended to have had less stereotypic demonstrators than the other ten observer mice. Overall, highly stereotypic mice thus received more agonism — an effect with obvious welfare implications that can be reduced with enrichment — and seemed potentially less effective at inducing flavour preferences in conspecifics. Such effects are consistent with social impairment, suggesting that reducing SB may perhaps enhance interactions between conspecifics.

While unobscured and radio-quiet active galactic nuclei are regularly being found at redshifts $z > 6$ , their obscured and radio-loud counterparts remain elusive. We build upon our successful pilot study, presenting a new sample of low-frequency-selected candidate high-redshift radio galaxies (HzRGs) over a sky area 20 times larger. We have refined our selection technique, in which we select sources with curved radio spectra between 72–231 MHz from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. In combination with the requirements that our GLEAM-selected HzRG candidates have compact radio morphologies and be undetected in near-infrared $K_{\rm s}$ -band imaging from the Visible and Infrared Survey Telescope for Astronomy Kilo-degree Infrared Galaxy (VIKING) survey, we find 51 new candidate HzRGs over a sky area of approximately $1200\ \mathrm{deg}^2$ . Our sample also includes two sources from the pilot study: the second-most distant radio galaxy currently known, at $z=5.55$ , with another source potentially at $z \sim 8$ . We present our refined selection technique and analyse the properties of the sample. We model the broadband radio spectra between 74 MHz and 9 GHz by supplementing the GLEAM data with both publicly available data and new observations from the Australia Telescope Compact Array at 5.5 and 9 GHz. In addition, deep $K_{\rm s}$ -band imaging from the High-Acuity Widefield K-band Imager (HAWK-I) on the Very Large Telescope and from the Southern Herschel Astrophysical Terahertz Large Area Survey Regions $K_{\rm s}$ -band Survey (SHARKS) is presented for five sources. We discuss the prospects of finding very distant radio galaxies in our sample, potentially within the epoch of reionisation at $z \gtrsim 6.5$ .

We describe a new low-frequency wideband radio survey of the southern sky. Observations covering 72–231 MHz and Declinations south of $+30^\circ$ have been performed with the Murchison Widefield Array “extended” Phase II configuration over 2018–2020 and will be processed to form data products including continuum and polarisation images and mosaics, multi-frequency catalogues, transient search data, and ionospheric measurements. From a pilot field described in this work, we publish an initial data release covering 1,447 $\mathrm{deg}^2$ over $4\,\mathrm{h}\leq \mathrm{RA}\leq 13\,\mathrm{h}$ , $-32.7^\circ \leq \mathrm{Dec} \leq -20.7^\circ$ . We process twenty frequency bands sampling 72–231 MHz, with a resolution of 2′–45′′, and produce a wideband source-finding image across 170–231 MHz with a root mean square noise of $1.27\pm0.15\,\mathrm{mJy\,beam}^{-1}$ . Source-finding yields 78,967 components, of which 71,320 are fitted spectrally. The catalogue has a completeness of 98% at ${{\sim}}50\,\mathrm{mJy}$ , and a reliability of 98.2% at $5\sigma$ rising to 99.7% at $7\sigma$ . A catalogue is available from Vizier; images are made available via the PASA datastore, AAO Data Central, and SkyView. This is the first in a series of data releases from the GLEAM-X survey.