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During the past two decades, several reports have documented substantial support from clinicians, policy-makers, and the general public for the use of advance directives, yet studies continue to find that only a minority of individuals (10 to 25 percent) have completed these legal documents. Advance directives are written instructions, such as living wills or durable powers of attorney for health care, which describe an individual's medical treatment wishes in the event that individual becomes incapacitated in the future. The completion and use of advance directives is one of several components of the broader activity of advance care planning, that is, the overall planning and communication of personal wishes concerning future medical care.
In December 1991, the federal Patient Self-Determination Act (PSDA) became effective. Promoted as a federal initiative to enhance an individual's control over medical treatment decision making and, therefore, patient autonomy and self-determination, PSDA placed several new requirements on health care organizations receiving Medicare or Medicaid payments.
The rise of multi-party processes in which people with quite different ties to a region, natural resource-related industry, or environmental issue work collaboratively to hammer out mutually acceptable agreements is arguably one of the biggest shifts in environmental management over the past twenty-five years. This chapter engages in some sensemaking around this diverse and evolving phenomenon in two ways. First, an approach to designing collaborative natural resource-related discourse with a particularly strong theoretical foundation (Collaborative Learning) is presented to illustrate how theory is manifest in practice. Second a recent best practices/common features list is examined through the perspectives of four social science theorists: Max Weber, Pierre Bourdieu, Niklas Luhmann, and Muzafer Sherif. The practical recommendations that emerge from this list is largely consistent with the larger social and communicative dynamics articulated by these theorists.
Late Pleistocene and Early Holocene aeolian deposits in Tasmania are extensive in the present subhumid climate zone but also occur in areas receiving >1000 mm of rain annually. Thermoluminescence, optically stimulated luminescence, and radiocarbon ages indicate that most of the deposits formed during periods of cold climate. Some dunes are remnants of longitudinal desert dunes sourced from now-inundated continental shelves which were previously semi-arid. Others formed near source, often in the form of lunettes east of seasonally-dry lagoons in the previously semi-arid Midlands and southeast of Tasmania, or as accumulations close to floodplains of major rivers, or as sandsheets in exposed areas. Burning of vegetation by the Aboriginal population after 40 ka is likely to have influenced sediment supply. A key site for determining climate variability in southern Tasmania is Maynes Junction which records three periods of aeolian deposition (at ca. 90, 32 and 20 ka), interspersed with periods of hillslope instability. Whether wind speeds were higher than at present during the last glacial period is uncertain, but shells in the Mary Ann Bay sandsheet near Hobart and particle size analysis of the Ainslie dunes in northeast Tasmania suggest stronger winds during the last glacial period than at present.
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
We evaluated whether memory recall following an extended (1 week) delay predicts cognitive and brain structural trajectories in older adults.
Method:
Clinically normal older adults (52–92 years old) were followed longitudinally for up to 8 years after completing a memory paradigm at baseline [Story Recall Test (SRT)] that assessed delayed recall at 30 min and 1 week. Subsets of the cohort underwent neuroimaging (N = 134, mean age = 75) and neuropsychological testing (N = 178–207, mean ages = 74–76) at annual study visits occurring approximately 15–18 months apart. Mixed-effects regression models evaluated if baseline SRT performance predicted longitudinal changes in gray matter volumes and cognitive composite scores, controlling for demographics.
Results:
Worse SRT 1-week recall was associated with more precipitous rates of longitudinal decline in medial temporal lobe volumes (p = .037), episodic memory (p = .003), and executive functioning (p = .011), but not occipital lobe or total gray matter volumes (demonstrating neuroanatomical specificity; p > .58). By contrast, SRT 30-min recall was only associated with longitudinal decline in executive functioning (p = .044).
Conclusions:
Memory paradigms that capture longer-term recall may be particularly sensitive to age-related medial temporal lobe changes and neurodegenerative disease trajectories.
To report feasibility, early outcomes and challenges of implementing a 14-day threshold for undertaking surgical tracheostomy in the critically ill coronavirus disease 2019 patient.
Methods
Twenty-eight coronavirus disease 2019 patients underwent tracheostomy. Demographics, risk factors, ventilatory assistance, organ support and logistics were assessed.
Results
The mean time from intubation to tracheostomy formation was 17.0 days (standard deviation = 4.4, range 8–26 days). Mean time to decannulation was 15.8 days (standard deviation = 9.4) and mean time to intensive care unit stepdown to a ward was 19.2 days (standard deviation = 6.8). The time from intubation to tracheostomy was strongly positively correlated with: duration of mechanical ventilation (r(23) = 0.66; p < 0.001), time from intubation to decannulation (r(23) = 0.66; p < 0.001) and time from intubation to intensive care unit discharge (r(23) = 0.71; p < 0.001).
Conclusion
Performing a tracheostomy in coronavirus disease 2019 positive patients at 8–14 days following intubation is compatible with favourable outcomes. Multidisciplinary team input is crucial to patient selection.
The low-frequency linearly polarised radio source population is largely unexplored. However, a renaissance in low-frequency polarimetry has been enabled by pathfinder and precursor instruments for the Square Kilometre Array. In this second paper from the POlarised GaLactic and Extragalactic All-Sky MWA Survey-the POlarised GLEAM Survey, or POGS-we present the results from our all-sky MWA Phase I Faraday Rotation Measure survey. Our survey covers nearly the entire Southern sky in the Declination range
$-82^\circ$
to
$+30^\circ$
at a resolution between around three and seven arcminutes (depending on Declination) using data in the frequency range 169−231 MHz. We have performed two targeted searches: the first covering 25 489 square degrees of sky, searching for extragalactic polarised sources; the second covering the entire sky South of Declination
$+30^\circ$
, searching for known pulsars. We detect a total of 517 sources with 200 MHz linearly polarised flux densities between 9.9 mJy and 1.7 Jy, of which 33 are known radio pulsars. All sources in our catalogues have Faraday rotation measures in the range
$-328.07$
to
$+279.62$
rad m−2. The Faraday rotation measures are broadly consistent with results from higher-frequency surveys, but with typically more than an order of magnitude improvement in the precision, highlighting the power of low-frequency polarisation surveys to accurately study Galactic and extragalactic magnetic fields. We discuss the properties of our extragalactic and known-pulsar source population, how the sky distribution relates to Galactic features, and identify a handful of new pulsar candidates among our nominally extragalactic source population.
To make a power spectrum (PS) detection of the 21-cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to ‘shapelets’, an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular resolution of the data is changed. We find that when increasing the angular resolution of the data, the MS CLEAN model worsens at large angular scales. When testing on real Murchison Widefield Array data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation, we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed.
Resolving the detailed hydrodynamics of a slender body immersed in highly viscous Newtonian fluid has been the subject of extensive research, applicable to a broad range of biological and physical scenarios. In this work, we expand upon classical theories developed over the past fifty years, deriving an algebraically accurate slender-body theory that may be applied to a wide variety of body shapes, ranging from biologically inspired tapering flagella to highly oscillatory body geometries with only weak constraints, most significantly requiring that cross-sections be circular. Inspired by well known analytic results for the flow around a prolate ellipsoid, we pose an ansatz for the velocity field in terms of a regular integral of regularised Stokes-flow singularities with prescribed, spatially varying regularisation parameters. A detailed asymptotic analysis is presented, seeking a uniformly valid expansion of the ansatz integral, accurate at leading algebraic order in the geometry aspect ratio, to enforce no-slip boundary conditions and thus analytically justify the slender-body theory developed in this framework. The regularisation within the ansatz additionally affords significant computational simplicity for the subsequent slender-body theory, with no specialised quadrature or numerical techniques required to evaluate the regular integral. Furthermore, in the special case of slender bodies with a straight centreline in uniform flow, we derive a slender-body theory that is particularly straightforward via use of the analytic solution for a prolate ellipsoid. We evidence the validity of our simple theory with explicit numerical examples for a wide variety of slender bodies, and highlight a potential robustness of our methodology beyond its rigorously justified scope.
The Murchison Widefield Array (MWA) has observed the entire southern sky (Declination,
$\delta< 30^{\circ}$
) at low radio frequencies, over the range 72–231MHz. These observations constitute the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey, and we use the extragalactic catalogue (EGC) (Galactic latitude,
$|b| >10^{\circ}$
) to define the GLEAM 4-Jy (G4Jy) Sample. This is a complete sample of the ‘brightest’ radio sources (
$S_{\textrm{151\,MHz}}>4\,\text{Jy}$
), the majority of which are active galactic nuclei with powerful radio jets. Crucially, low-frequency observations allow the selection of such sources in an orientation-independent way (i.e. minimising the bias caused by Doppler boosting, inherent in high-frequency surveys). We then use higher-resolution radio images, and information at other wavelengths, to morphologically classify the brightest components in GLEAM. We also conduct cross-checks against the literature and perform internal matching, in order to improve sample completeness (which is estimated to be
$>95.5$
%). This results in a catalogue of 1863 sources, making the G4Jy Sample over 10 times larger than that of the revised Third Cambridge Catalogue of Radio Sources (3CRR;
$S_{\textrm{178\,MHz}}>10.9\,\text{Jy}$
). Of these G4Jy sources, 78 are resolved by the MWA (Phase-I) synthesised beam (
$\sim2$
arcmin at 200MHz), and we label 67% of the sample as ‘single’, 26% as ‘double’, 4% as ‘triple’, and 3% as having ‘complex’ morphology at
$\sim1\,\text{GHz}$
(45 arcsec resolution). We characterise the spectral behaviour of these objects in the radio and find that the median spectral index is
$\alpha=-0.740 \pm 0.012$
between 151 and 843MHz, and
$\alpha=-0.786 \pm 0.006$
between 151MHz and 1400MHz (assuming a power-law description,
$S_{\nu} \propto \nu^{\alpha}$
), compared to
$\alpha=-0.829 \pm 0.006$
within the GLEAM band. Alongside this, our value-added catalogue provides mid-infrared source associations (subject to 6” resolution at 3.4
$\mu$
m) for the radio emission, as identified through visual inspection and thorough checks against the literature. As such, the G4Jy Sample can be used as a reliable training set for cross-identification via machine-learning algorithms. We also estimate the angular size of the sources, based on their associated components at
$\sim1\,\text{GHz}$
, and perform a flux density comparison for 67 G4Jy sources that overlap with 3CRR. Analysis of multi-wavelength data, and spectral curvature between 72MHz and 20GHz, will be presented in subsequent papers, and details for accessing all G4Jy overlays are provided at https://github.com/svw26/G4Jy.
The entire southern sky (Declination,
$\delta< 30^{\circ}$
) has been observed using the Murchison Widefield Array (MWA), which provides radio imaging of
$\sim$
2 arcmin resolution at low frequencies (72–231 MHz). This is the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey, and we have previously used a combination of visual inspection, cross-checks against the literature, and internal matching to identify the ‘brightest’ radio-sources (
$S_{\mathrm{151\,MHz}}>4$
Jy) in the extragalactic catalogue (Galactic latitude,
$|b| >10^{\circ}$
). We refer to these 1 863 sources as the GLEAM 4-Jy (G4Jy) Sample, and use radio images (of
${\leq}45$
arcsec resolution), and multi-wavelength information, to assess their morphology and identify the galaxy that is hosting the radio emission (where appropriate). Details of how to access all of the overlays used for this work are available at https://github.com/svw26/G4Jy. Alongside this we conduct further checks against the literature, which we document here for individual sources. Whilst the vast majority of the G4Jy Sample are active galactic nuclei with powerful radio-jets, we highlight that it also contains a nebula, two nearby, star-forming galaxies, a cluster relic, and a cluster halo. There are also three extended sources for which we are unable to infer the mechanism that gives rise to the low-frequency emission. In the G4Jy catalogue we provide mid-infrared identifications for 86% of the sources, and flag the remainder as: having an uncertain identification (129 sources), having a faint/uncharacterised mid-infrared host (126 sources), or it being inappropriate to specify a host (2 sources). For the subset of 129 sources, there is ambiguity concerning candidate host-galaxies, and this includes four sources (B0424–728, B0703–451, 3C 198, and 3C 403.1) where we question the existing identification.
Death is the end point of a process of irreversible and progressive loss of vital organ function leading to certain and irreversible cessation of the characteristics that define life. Perhaps surprisingly, there is no globally accepted definition of what constitutes death, and in the UK, there is no statutory definition. However, successive working parties of the medical Royal Colleges have produced guidance for the diagnosis and confirmation of neurological death and these have been revised more recently to include death after cardiorespiratory arrest.1 The irreversible loss of consciousness with the irreversible loss of the capacity to breathe produced by brain stem death (BSD) is accepted in the UK as the death of the individual and can be diagnosed using clinical tests of brain stem function. Diagnosis of BSD allows the discontinuation of treatment, which is no longer in the patient’s best interest and thereby reduces distress to relatives, carers and positively impacts on the costs of health care. Diagnosing BSD on these ethical, humanitarian and utilitarian grounds also facilitates organ donation when patients and families choose to donate.
We recently found that, in mice, independently of orosensory input, sucrose consumption is sufficient to condition the development of spout preferences and dopamine release in the ventral striatum.
Objectives
To clarify if the appetitive behavioral and dopaminergic responses to the postingestive effects of calorie-containing sugars reflect preabsorptive or postabsorptive events.
Aims
To understand if endovenous injection of glucose is sufficient to condition spout preferences and dopamine release.
Methods
Measurements of the behavioural, metabolic and neurochemical effects of the administration of glucose solutions, enterically, and in the jugular (JV) or hepatic-portal (HPV) veins of rats.
Results
High concentration glucose solutions administered in the JV were sufficient to condition spout preferences in a two-bottle behavioral task. Additionally, a low concentration glucose solution conditioned robust behavioral responses when administered in the HPV, but not the JV. Finally, using fast-scan cyclic voltammetry we found that, in accordance to behavioral findings, a low concentration glucose solution caused an increase of spontaneous dopamine release events in the nucleus accumbens shell when administered in the HPV, but not the JV.
Conclusions
The postabsorptive effects of glucose are sufficient to mimic the behavioral and dopaminergic responses that result from sugar consumption. Furthermore, glycemia levels in the HPV contribute more significantly for this effect than systemic glycemia, arguing for the participation of an intra-abdominal visceral sensor for glucose.
How can people achieve successful communication when using novel signs? Previous studies show that iconic signs (i.e. signs that directly resemble their referent) enhance communication success. In this paper, we test if enculturated signs (i.e. signs informed by interlocutors’ shared culture) also enhance communication success. Children, who have spent less time in their linguistic community, have less cultural knowledge to inform their sign innovation. A natural prediction is that younger children's signs will be less enculturated, more diverse and less successful compared with older children and adults. We examined sign innovation in children aged between 6 and 12 years (N = 54) and adults (N = 18). Sign enculturation, diversity and iconicity were rated. As predicted, younger children innovated less enculturated and more diverse signs, and communicated less successfully than older children and adults. Sign enculturation and iconicity uniquely contributed to communication success. This is the first study to demonstrate that enculturated signs enhance communication.
The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low-frequency (80–300 MHz) southern sky. Since beginning operations in mid-2013, the MWA has opened a new observational window in the southern hemisphere enabling many science areas. The driving science objectives of the original design were to observe 21 cm radiation from the Epoch of Reionisation (EoR), explore the radio time domain, perform Galactic and extragalactic surveys, and monitor solar, heliospheric, and ionospheric phenomena. All together
$60+$
programs recorded 20 000 h producing 146 papers to date. In 2016, the telescope underwent a major upgrade resulting in alternating compact and extended configurations. Other upgrades, including digital back-ends and a rapid-response triggering system, have been developed since the original array was commissioned. In this paper, we review the major results from the prior operation of the MWA and then discuss the new science paths enabled by the improved capabilities. We group these science opportunities by the four original science themes but also include ideas for directions outside these categories.
We have detected 27 new supernova remnants (SNRs) using a new data release of the GLEAM survey from the Murchison Widefield Array telescope, including the lowest surface brightness SNR ever detected, G 0.1 – 9.7. Our method uses spectral fitting to the radio continuum to derive spectral indices for 26/27 candidates, and our low-frequency observations probe a steeper spectrum population than previously discovered. None of the candidates have coincident WISE mid-IR emission, further showing that the emission is non-thermal. Using pulsar associations we derive physical properties for six candidate SNRs, finding G 0.1 – 9.7 may be younger than 10 kyr. Sixty per cent of the candidates subtend areas larger than 0.2 deg2 on the sky, compared to < 25% of previously detected SNRs. We also make the first detection of two SNRs in the Galactic longitude range 220°–240°.
This work makes available a further
$2\,860~\text{deg}^2$
of the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey, covering half of the accessible galactic plane, across 20 frequency bands sampling 72–231 MHz, with resolution
$4\,\text{arcmin}-2\,\text{arcmin}$
. Unlike previous GLEAM data releases, we used multi-scale CLEAN to better deconvolve large-scale galactic structure. For the galactic longitude ranges
$345^\circ < l < 67^\circ$
,
$180^\circ < l < 240^\circ$
, we provide a compact source catalogue of 22 037 components selected from a 60-MHz bandwidth image centred at 200 MHz, with RMS noise
$\approx10-20\,\text{mJy}\,\text{beam}^{-1}$
and position accuracy better than 2 arcsec. The catalogue has a completeness of 50% at
${\approx}120\,\text{mJy}$
, and a reliability of 99.86%. It covers galactic latitudes
$1^\circ\leq|b|\leq10^\circ$
towards the galactic centre and
$|b|\leq10^\circ$
for other regions, and is available from Vizier; images covering
$|b|\leq10^\circ$
for all longitudes are made available on the GLEAM Virtual Observatory (VO).server and SkyView.
We examined the latest data release from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey covering 345° < l < 60° and 180° < l < 240°, using these data and that of the Widefield Infrared Survey Explorer to follow up proposed candidate Supernova Remnant (SNR) from other sources. Of the 101 candidates proposed in the region, we are able to definitively confirm ten as SNRs, tentatively confirm two as SNRs, and reclassify five as H ii regions. A further two are detectable in our images but difficult to classify; the remaining 82 are undetectable in these data. We also investigated the 18 unclassified Multi-Array Galactic Plane Imaging Survey (MAGPIS) candidate SNRs, newly confirming three as SNRs, reclassifying two as H ii regions, and exploring the unusual spectra and morphology of two others.
The Murchison Widefield Array (MWA) is an electronically steered low-frequency (<300 MHz) radio interferometer, with a ‘slew’ time less than 8 s. Low-frequency (∼100 MHz) radio telescopes are ideally suited for rapid response follow-up of transients due to their large field of view, the inverted spectrum of coherent emission, and the fact that the dispersion delay between a 1 GHz and 100 MHz pulse is on the order of 1–10 min for dispersion measures of 100–2000 pc/cm3. The MWA has previously been used to provide fast follow-up for transient events including gamma-ray bursts (GRBs), fast radio bursts (FRBs), and gravitational waves, using systems that respond to gamma-ray coordinates network packet-based notifications. We describe a system for automatically triggering MWA observations of such events, based on Virtual Observatory Event standard triggers, which is more flexible, capable, and accurate than previous systems. The system can respond to external multi-messenger triggers, which makes it well-suited to searching for prompt coherent radio emission from GRBs, the study of FRBs and gravitational waves, single pulse studies of pulsars, and rapid follow-up of high-energy superflares from flare stars. The new triggering system has the capability to trigger observations in both the regular correlator mode (limited to ≥0.5 s integrations) and using the Voltage Capture System (VCS, 0.1 ms integration) of the MWA and represents a new mode of operation for the MWA. The upgraded standard correlator triggering capability has been in use since MWA observing semester 2018B (July–Dec 2018), and the VCS and buffered mode triggers will become available for observing in a future semester.