Geographic Equity in Hospital Utilization: Canadian Evidence Using a Concentration-Index Approach

Distance-related geographic barriers challenge the ability of health systems to allocate health care resources equitably according to need. The paper adapts the concentration-index approach, commonly used for measuring income-related equity, to assess distance-related equity in hospital utilization in the province of Ontario, Canada. The analysis is based on individual-level data from the Canadian Community Health Survey, which provides information on respondents’ hospital utilization, health status, demographic, socio-economic status and location, merged with data on Ontario hospitals, and a geo-coded measure of each respondent’s distance to the nearest general acute-care hospital. We find no evidence of a relationship between distance to the nearest hospital and either the probability of hospitalization or the annual number of hospital nights. Supplementary analyses provide insight into hypothesized pathways between distance and hospitalization. Although having a regular medical doctor is positively associated with distance to the nearest hospital, controlling for this does not affect the estimated distance-hospitalization relationship. Both the size and occupancy rate of the nearest hospital are correlated with distance and are strongly related to the probability of hospitalization, but again controlling for these factors did not affect the estimated relationship between hospital use and distance to the nearest hospital. We do, however, find a strong positive gradient between the probability of hospitalization and distance to the nearest large hospital. This gradient is driven by the fact that, for most of those far from a large hospital, the nearest hospital is small with a low occupancy rate. Calculation of the distance-related horizontal inequity index confirms no distance-related inequity in hospital utilization when distance is measured to the nearest hospital of any size; however, when distance is instead measured to the nearest large hospital, we observe large, pro-distance inequity. These distance-use relationships are not captured by traditional geographic measures based on measures of urbanization/ruralness.hospital utilization, equity, geography

Discovery of a young, highly scattered pulsar PSR J1032-5804 with the Australian SKA Pathfinder

We report the discovery of a young, highly scattered pulsar in a search for highly circularly polarized radio sources as part of the Australian Square Kilometre Array Pathfinder (ASKAP) Variables and Slow Transients (VAST) survey. In follow-up observations with Murriyang/Parkes, we identified PSR J1032-5804 and measured a period of 78.7 ms, dispersion measure (DM) of 819$\pm$4 pc cm$^{-3}$, rotation measure of -2000$\pm$1 rad m$^{-2}$, and a characteristic age of 34.6 kyr. We found a pulse scattering timescale at 3 GHz of ~22 ms, implying a timescale at 1 GHz of ~3845 ms, which is the third most scattered pulsar known and explains its non-detection in previous pulsar surveys. We discuss the identification of a possible pulsar wind nebula and supernova remnant in the pulsar's local environment by analyzing the pulsar spectral energy distribution and the surrounding extended emission from multiwavelength images. Our result highlights the possibility of identifying extremely scattered pulsars from radio continuum images. Ongoing and future large-scale radio continuum surveys will offer us an unprecedented opportunity to find more extreme pulsars (e.g., highly scattered, highly intermittent, highly accelerated), which will enhance our understanding of the characteristics of pulsars and the interstellar medium.Comment: 15 pages, 10 figures, 2 tables. Accepted for publication in Ap

Discovery of radio eclipses from 4FGL J1646.5−-4406: a new candidate redback pulsar binary

Large widefield surveys make possible the serendipitous discovery of rare sub-classes of pulsars. One such class are "spider"-type pulsar binaries, comprised of a pulsar in a compact orbit with a low-mass (sub)stellar companion. In a search for circularly-polarized radio sources in ASKAP Pilot Survey observations, we discovered highly variable and circularly polarized emission from a radio source within the error region of the $\gamma$-ray source {4FGL}~J1646.5$-$4406. The variability is consistent with the eclipse of a compact, steep-spectrum source behind ablated material from a companion in a $\sim 5.3\,$h binary orbit. Based on the eclipse properties and spatial coincidence with {4FGL} J1646.5$-$4406, we argue that the source is likely a recycled pulsar in a "redback" binary system. Using properties of the eclipses from ASKAP and Murchison Widefield Array observations, we provide broad constraints on the properties of the eclipse medium. We identified a potential optical/infra-red counterpart in archival data consistent with a variable low-mass star. Using the Parkes Radio Telescope "Murriyang" and MeerKAT, we searched extensively for radio pulsations but yielded no viable detections of pulsed emission. We suggest that the non-detection of pulses is due to scattering in the intra-binary material, but scattering from the ISM can also plausibly explain the pulse non-detections if the interstellar dispersion measure exceeds $\sim$600$\,$pc$\,$cm$^{-3}$. Orbital constraints derived from optical observations of the counterpart would be highly valuable for future $\gamma$-ray pulsation searches, which may confirm the source nature as a pulsar.Comment: Submitted to MNRAS. 13 Pages, 10 figures, 3 table

WSCLEAN: an implementation of a fast, generic wide-field imager for radio astronomy

Astronomical wide-field imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new wide-field interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependences of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarization correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the lowfrequency Square Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released

The Murchison Widefield Array Transients Survey (MWATS). A search for low frequency variability in a bright Southern hemisphere sample

We report on a search for low-frequency radio variability in 944 bright (> 4Jy at 154 MHz) unresolved, extragalactic radio sources monitored monthly for several years with the Murchison Widefield Array. In the majority of sources we find very low levels of variability with typical modulation indices < 5%. We detect 15 candidate low frequency variables that show significant long term variability (>2.8 years) with time-averaged modulation indices M = 3.1 - 7.1%. With 7/15 of these variable sources having peaked spectral energy distributions, and only 5.7% of the overall sample having peaked spectra, we find an increase in the prevalence of variability in this spectral class. We conclude that the variability seen in this survey is most probably a consequence of refractive interstellar scintillation and that these objects must have the majority of their flux density contained within angular diameters less than 50 milli-arcsec (which we support with multi-wavelength data). At 154 MHz we demonstrate that interstellar scintillation time-scales become long (~decades) and have low modulation indices, whilst synchrotron driven variability can only produce dynamic changes on time-scales of hundreds of years, with flux density changes less than one milli-jansky (without relativistic boosting). From this work we infer that the low frequency extra-galactic southern sky, as seen by SKA-Low, will be non-variable on time-scales shorter than one year.Comment: 19 pages, 11 figure

An all-sky survey of circular polarization at 200 MHz

We present results from the first all-sky radio survey in circular polarization. The survey uses the Murchison Widefield Array (MWA) to cover 30 900 sq deg, over declinations south of +30° and north of -86° centred at 200MHz (over a 169-231MHz band).We achieve a spatial resolution of ~3 arcmin and a typical sensitivity of 3.0mJy PSF-1over most of the survey region. We demonstrate a new leakage mitigation technique that reduces the leakage from total intensity into circular polarization by an order of magnitude. In a blind survey of the imaged region, we detect 14 pulsars in circular polarization above a 6s threshold. We also detect six transient sources associated with artificial satellites. A targeted survey of 2376 pulsars within the surveyed region yielded 33 detections above 4s. Looking specifically at pulsars previously detected at 200 MHz in total intensity, this represents a 35 per cent detection rate. We also conducted a targeted survey of 2400 known flare stars, this resulted in two tentative detections above 4s. A similar targeted search for 1506 known exoplanets in the field yielded no detections above 4s. The success of the survey suggests that similar surveys at longer wavelength bands and of deeper fields are warranted

ARMED to ESCAPE COVID-19 : the impact of COVID-19 on a mixed methods feasibility study of a weight management, education and physical function programme for patients with knee osteoarthritis at the primary/secondary care interface

OBJECTIVES: This study was designed to test the feasibility of running a trial to compare the effectiveness of a combined weight management and physical function programme for patients with knee osteoarthritis ARMED (Arthritis Rehabilitation through the Management of Exercise and Diet) with usual care ESCAPE pain (Enabling Self-management and Coping with Arthritic Pain using Exercise). The COVID-19 pandemic interruption allowed additional measurement of the qualitative ‘lived in’ experiences of this patient group during the pandemic and also their appetite for virtual health. PARTICIPANTS: Thirty-two patients with knee osteoarthritis were recruited from a combined primary/secondary care waiting list and were allocated to either a six-week intervention group (ARMED) or to the six-week usual care ESCAPE pain group (Enabling Self-management and Coping with Arthritic Pain using Exercise) group. RESULTS: The intervention programme was interrupted after three weeks by COVID-19. Fifteen patients were reassessed after the first stage. The average attendance was 92% with 6 patients attending all sessions, 5 attending 5/6, 1 attending 4/6 and 2 attending 3/6. One subject dropped out and 15/16 patients completed all outcome measurements. All patients completed the KOOS knee score and the Short Warwick-Edinburgh Mental Well Being Scale to evaluate anxiety and depression. There was a statistically significant improvement in pain, activities of daily living, quality of life and mental health and well-being scores from time one to time 2. The mean weight, BMI and waist measurements were reduced also from time one to time 2, but these failed to reach significance. The semi-structured interviews provided rich information on enablers and barriers to coping in lockdown, benefits of the ARMED programme to increasing physical activity and weight management and enablers and barriers to redesigning the programme for online delivery. CONCLUSIONS: Evaluation of preliminary data from this feasibility study supports the three-week intervention combining education, exercise and weight management in this patient group even during a pandemic. Based on the results of the qualitative interviews, we have now redesigned our programme to present it virtually. We hope to present the results of our virtual feasibility study later in 2021