This study estimates the incubation period of COVID-19 among locally transmitted cases, and its association with age to better inform public health measures in containing COVID-19. Epidemiological data of all PCR-confirmed COVID-19 cases from all restructured hospitals in Singapore were collected between 23 January 2020 and 2 April 2020. Activity mapping and detailed epidemiological investigation were conducted by trained personnel. Positive cases without clear exposure to another positive case were excluded from the analysis. One hundred and sixty-four cases (15.6% of patients) met the inclusion criteria during the defined period. The crude median incubation period was 5 days (range 1–12 days) and median age was 42 years (range 5–79 years). The median incubation period among those 70 years and older was significantly longer than those younger than 70 years (8 vis-à-vis 5 days, P = 0.040). Incubation period was negatively correlated with day of illness in both groups. These findings support current policies of 14-day quarantine periods for close contacts of confirmed cases and 28 days for monitoring infections in known clusters. An elderly person who may have a longer incubation period than a younger counterpart may benefit from earlier and proactive testing, especially after exposure to a positive case.

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.

The present study aimed to compare the effects of drinking different types of coffee before a high-glycaemic index (GI) meal on postprandial glucose metabolism and to assess the effects of adding milk and sugar into coffee. In this randomised, crossover, acute feeding study, apparently healthy adults (n 21) consumed the test drink followed by a high-GI meal in each session. Different types of coffee (espresso, instant, boiled and decaffeinated, all with milk and sugar) and plain water were tested in separate sessions, while a subset of the participants (n 10) completed extra sessions using black coffees. Postprandial levels of glucose, insulin, active glucagon-like peptide 1 (GLP-1) and nitrotyrosine between different test drinks were compared using linear mixed models. Results showed that only preloading decaffeinated coffee with milk and sugar led to significantly lower glucose incremental AUC (iAUC; 14 % lower, P = 0·001) than water. Preloading black coffees led to greater postprandial glucose iAUC than preloading coffees with milk and sugar added (12–35 % smaller, P < 0·05 for all coffee types). Active GLP-1 and nitrotyrosine levels were not significantly different between test drinks. To conclude, preloading decaffeinated coffee with milk and sugar led to a blunted postprandial glycaemic response after a subsequent high-GI meal, while adding milk and sugar into coffee could mitigate the impairment effect of black coffee towards postprandial glucose responses. These findings may partly explain the positive effects of coffee consumption on glucose metabolism.

Introduction: Point-of-care ultrasound (POCUS) has become standard practice in emergency departments ranging from remote rural hospitals to well-resourced academic centres. To facilitate quality assurance, the Canadian Association of Emergency Physicians (CAEP) recommends image archiving. Due in part to poor infrastructure and lack of a national standard, however, archiving remains uncommon. Our objective was to establish a minimum standard archiving protocol for the core emergency department POCUS indications. Methods: Itemization of potential archiving standards was created through an extensive literature review. An online, three-round, modified Delphi survey was conducted with the thirteen POCUS experts on the national CAEP Emergency Ultrasound Committee tasked with representing diverse practice locations and experiences. Participants were surveyed to determine the images or clips, measurements, mode, and number of views that should comprise the minimum standard for archiving. Consensus was pre-defined as 80%. Results: All thirteen experts participated fully in the three rounds. In establishing minimum image archiving standards for emergency department POCUS, complete consensus was achieved for first trimester pregnancy, hydronephrosis, cardiac activity versus standstill, lower extremity deep venous thrombosis, and ultrasound-guided central line placement. Consensus was achieved for the majority of statements regarding abdominal aortic aneurysm, extended focused assessment with sonography in trauma, pericardial effusion, left and right ventricular function, thoracic B-line assessment, cholelithiasis and cholecystitis scans. In total, consensus was reached for 58 of 69 statements (84.1%). This included agreement on 41 of 43 statements (95.3%) describing mandatory images for archiving in the above indications. Conclusion: Our modified Delphi-derived consensus represents the first national standard archiving requirements for emergency department POCUS. Depending on the clinical context, additional images may be required beyond this minimum standard to support a diagnosis.

Introduction: Several recent observational studies have presented concerning data regarding the safety of cardioversion (CV) for acute atrial fibrillation and flutter (AAFF). We conducted this systematic review to determine whether it is safe to cardiovert AAFF patients without prescribing oral anticoagulation (OAC) post-CV for those who are CHADS-65 negative. Methods: We conducted a librarian assisted search of MEDLINE, Embase, and Cochrane from inception through November 23, 2019. We included observational studies and randomized trials reporting thromboembolic (TE) events (i.e. stroke, transient ischemic attack, or systemic thromboembolism) within 30 days following CV in patients with AAFF, where onset of symptoms was <48 hours. Two reviewers independently screened studies and extracted data. The main outcome was risk of TE events within 30 days post-CV, stratified by OAC use. Risk of bias was assessed with the Quality in Prognostic Studies (QUIPS) tool. The primary analysis was based on prospective studies and the secondary analysis was based on retrospective studies. We performed meta-analyses for TE events where 2 or more studies were available, by applying the DerSimonian-Laird random-effects model. We implemented analyses stratified by study design using Open MetaAnalyst and generated the forest plots. Results: Our search yielded 969 titles; 74 were selected for full-text review and 20 studies were included in the review. The primary meta-analysis of 6 prospective studies, including two randomized trials, found a TE event rate of 0.15% (2 TE events/1,314 CVs). Within this prospective group, lack of OAC use was associated with a decreased risk of TE events (RR = 2.15 where RR >1 indicates increased risk of TE events with OAC compared to no OAC; 95% CI 0.50 to 9.31; I2 = 0%). Five of the 6 prospective studies had a low or moderate risk of bias in all QUIPS domains. Secondary meta-analysis of 6 retrospective studies revealed a TE event rate of 0.53% (56 TE events/10,521 CVs). This subgroup showed a trend favouring OAC use with decreased risk of TE events (RR = 0.34 where RR <1 suggests decreased risk of TE events with OAC; 95% CI 0.17 to 0.72; I2 = 0%). Conclusion: In the primary analysis of prospective studies, we found a low TE event rate following CV of AAFF, irrespective of OAC use. This contradicts previous analyses of retrospective studies. Our study supports the longstanding practice of not necessarily prescribing OAC post-CV in the ED for AAFF patients who are CHADS-65 negative.

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.

Introduction: Oxygen is commonly administered to prehospital patients presenting with acute myocardial infarction (AMI). We conducted a systematic review to determine if oxygen administration, in AMI, impacts patient outcomes. Methods: We conducted a systematic search using MeSH terms and keywords in Medline, Embase, Cochrane Database of Systematic Reviews, Cochrane Central, clinicaltrials.gov and ISRCTN for relevant randomized controlled trials and observational studies comparing oxygen administration and no oxygen administration. The outcomes of interest were: mortality (≤30 days, in-hospital, and intermediate 2-11 months), infarct size, and major adverse cardiac events (MACE). Risk of Bias assessments were performed and GRADE methodology was employed to assess quality and overall confidence in the effect estimate. A meta-analysis was performed using RevMan 5 software. Results: Our search yielded 1192 citations of which 48 studies were reviewed as full texts and a total of 8 studies were included in the analysis. All evidence was considered low or very low quality. Five studies reported on mortality finding low quality evidence of no benefit or harm. Low quality evidence demonstrated no benefit or harm from supplemental oxygen administration. Similarly, no benefit or harm was found in MACE or infarct size (very low quality). Normoxia was defined as oxygen saturation measured via pulse oximetry at ≥90% in one recent study and ≥94% in another. Conclusion: We found low and very low quality evidence that the administration of supplemental oxygen to normoxic patients experiencing AMI, provides no clear harm nor benefit for mortality or MACE. The evidence on infarct size was inconsistent and warrants further prospective examination.

Introduction: Opioids are routinely administered for analgesia to prehospital patients experiencing chest discomfort from acute myocardial infarction (AMI). We conducted a systematic review to determine if opioid administration impacts patient outcomes. Methods: We conducted a systematic search using MeSH terms and keywords in Medline, Embase, Cochrane Database of Systematic Reviews, Cochrane Central and Clinicaltrials.gov for relevant randomized controlled trials and observational studies comparing opioid administration in AMI patients from 1990 to 2017. The outcomes of interest were: all-cause short-term mortality (≤30 days), major adverse cardiac events (MACE), platelet activity and aggregation, immediate adverse events, infarct size, and analgesia. Included studies were hand searched for additional citations. Risk of Bias assessments were performed and GRADE methodology was employed to assess quality and overall confidence in the effect estimate. Results: Our search yielded 3001 citations of which 19 studies were reviewed as full texts and a total of 9 studies were included in the analysis. The studies predominantly reported on morphine as the opioid. Five studies reported on mortality (≤30 days), seven on MACE, four on platelet activity and aggregation, two on immediate adverse events, two on infarct size and none on analgesic effect. We found low quality evidence suggesting no benefit or harm in terms of mortality or MACE. However, low quality evidence indicates that opioids increase infarct size. Low-quality evidence also shows reduced serum P2Y12 (eg: clopidogrel and ticagrelor) active metabolite levels and increased platelet reactivity in the first several hours post administration following an increase in vomiting. Conclusion: We find low and very low quality evidence that the administration of opioids in STEMI may be adversely related to vomiting and some surrogate outcomes including increased infarct size, reduced serum P2Y12 levels, and increased platelet activity. We found no clear benefit or harm on patient-oriented clinical outcomes including mortality.

Introduction: When a patient is incapable of making medical decisions for themselves, choices are made according to the patient's previously expressed, wishes, values, and beliefs by a substitute decision maker (SDM). While interventions to engage patients in their own advance care planning exist, little is known about public readiness to act as a SDM on behalf of a loved one. This mixed-methods survey aimed to describe attitudes, enablers and barriers to preparedness to act as a SDM, and support for a population-level curriculum on the role of an SDM in end-of-life and resuscitative care. Methods: From November 2017 to June 2018, a mixed-methods street intercept survey was conducted in Ottawa, Canada. Descriptive statistics and logistic regression analysis were used to assess predictors of preparedness to be a SDM and understand support for a high school curriculum. Responses to open-ended questions were analyzed using inductive thematic analysis. Results: The 430 respondents were mostly female (56.5%) with an average age of 33.9. Although 73.0% of respondents felt prepared to be a SDM, 41.0% of those who reported preparedness never had a meaningful conversation with loved ones about their wishes in critical illness. The only predictors of SDM preparedness were the belief that one would be a future SDM (OR 2.36 95% CI 1.34-4.17), and age 50-64 compared to age 16-17 (OR 7.46 95% CI 1.25-44.51). Thematic enablers of preparedness included an understanding of a patient's wishes, the role of the SDM and strong familial relationships. Barriers included cultural norms, family conflict, and a need for time for high stakes decisions. Most respondents (71.9%) believed that 16 year olds should learn about SDMs. They noted age appropriateness, potential developmental and societal benefit, and improved decision making, while cautioning the need for a nuanced approach respectful of different maturity levels, cultures and individual experiences. Conclusion: This study reveals a concerning gap between perceived preparedness and actions taken in preparation to be an SDM for loved ones suffering critical illness. The results also highlight the potential role for high school education to address this gap. Future studies should further explore the themes identified to inform development of resources and curricula for improved health literacy in resuscitation and end-of-life care.

Angiostrongylus cantonensis (rat lungworm), a parasitic nematode, is expanding its distribution. Human infection, known as angiostrongyliasis, may manifest as eosinophilic meningitis, an emerging infectious disease. The range and incidence of this disease are expanding throughout the tropics and subtropics. Recently, the Hawaiian Islands have experienced an increase in reported cases. This study addresses factors affecting the parasite's distribution and projects its potential future distribution, using Hawaii as a model for its global expansion. Specimens of 37 snail species from the Hawaiian Islands were screened for the parasite using PCR. It was present on five of the six largest islands. The data were used to generate habitat suitability models for A. cantonensis, based on temperature and precipitation, to predict its potential further spread within the archipelago. The best current climate model predicted suitable habitat on all islands, with greater suitability in regions with higher precipitation and temperatures. Projections under climate change (to 2100) indicated increased suitability in regions with estimated increased precipitation and temperatures, suitable habitat occurring increasingly at higher elevations. Analogously, climate change could facilitate the spread of A. cantonensis from its current tropical/subtropical range into more temperate regions of the world, as is beginning to be seen in the continental USA.

The present experimental investigation characterises the dynamic response and wake structure of a sinusoidally rotating circular cylinder with a low mass ratio (defined as the ratio of the total oscillating mass to the displaced fluid mass) undergoing cross-stream flow-induced vibration (FIV). The study covers a wide parameter space spanning the forcing rotary oscillation frequency ratio $0\leqslant f_{r}^{\ast }\leqslant 4.5$ and the forcing rotation speed ratio $0\leqslant \unicode[STIX]{x1D6FC}_{r}^{\ast }\leqslant 2.0$ , at reduced velocities associated with the vortex-induced vibration (VIV) upper and lower amplitude response branches. Here, $f_{r}^{\ast }=f_{r}/f_{nw}$ and $\unicode[STIX]{x1D6FC}_{r}^{\ast }=\unicode[STIX]{x1D6FA}_{o}D/(2U)$ , where $f_{r}$ is the forcing rotary oscillation frequency, $f_{nw}$ is the natural frequency of the system in quiescent fluid (water), $\unicode[STIX]{x1D6FA}_{o}$ is the peak angular rotation speed, $D$ is the cylinder diameter and $U$ is the free-stream velocity; the reduced velocity is defined by $U^{\ast }=U/(\,f_{nw}D)$ . The fluid–structure system was modelled using a low-friction air-bearing system in conjunction with a free-surface recirculating water channel, with axial rotary motion provided by a microstepping motor. The cylinder was allowed to vibrate with only one degree of freedom transverse to the oncoming free-stream flow. It was found that in specific ranges of $f_{r}^{\ast }$ , the body vibration frequency may deviate from that seen in the non-rotating case and lock onto the forcing rotary oscillation frequency or its one-third subharmonic. The former is referred to as the ‘rotary lock-on’ (RLO) region and the latter as the ‘tertiary lock-on’ (TLO) region. Significant increases in the vibration amplitude and suppression of VIV could both be observed in different parts of the RLO and TLO regions. The peak amplitude response in the case of $U^{\ast }=5.5$ (upper branch) was observed to be $1.2D$ , an increase of approximately $50\,\%$ over the non-rotating case, while in the case of $U^{\ast }=8.0$ (lower branch), the peak amplitude response was $2.2D$ , a remarkable increase of $270\,\%$ over the non-rotating case. Notably, the results showed that the amplitude responses at moderate Reynolds numbers ( $Re=UD/\unicode[STIX]{x1D708}=2060$ and $2940$ , where $\unicode[STIX]{x1D708}$ is the kinematic viscosity of the fluid) in the present study showed significant differences from those of a previous low-Reynolds-number ( $Re=350$ ) numerical study at similar reduced velocities by Du & Sun (Phys. Fluids, vol. 14 (8), 2015, pp. 2767–2777). Remarkably, in an additional study examining the cylinder vibration as a function of $U^{\ast }$ while the fixed forcing rotary oscillation parameters were kept constant at $(f_{r}^{\ast },\unicode[STIX]{x1D6FC}_{r}^{\ast })=(1.0,1.0)$ , the cylinder experienced substantially larger oscillations than in the non-rotating case, and a rotation-induced galloping response was observed for $U^{\ast }>12$ , where the amplitude increased monotonically to reach approximately $3.0D$ at the highest reduced velocity ( $U^{\ast }=20$ ) tested. Furthermore, new wake modes were identified in the RLO and TLO regions using particle image velocimetry measurements at selected points in the $f_{r}^{\ast }-\unicode[STIX]{x1D6FC}_{r}^{\ast }$ parameter space.

The main goal of this paper is to provide insights into swash flow dynamics, generated by a non-breaking solitary wave on a steep slope. Both laboratory experiments and numerical simulations are conducted to investigate the details of runup and rundown processes. Special attention is given to the evolution of the bottom boundary layer over the slope in terms of flow separation, vortex formation and the development of a hydraulic jump during the rundown phase. Laboratory experiments were performed to measure the flow velocity fields by means of high-speed particle image velocimetry (HSPIV). Detailed pathline patterns of the swash flows and free-surface profiles were also visualized. Highly resolved computational fluid dynamics (CFD) simulations were carried out. Numerical results are compared with laboratory measurements with a focus on the velocities inside the boundary layer. The overall agreement is excellent during the initial stage of the runup process. However, discrepancies in the model/data comparison grow as time advances because the numerical model does not simulate the shoreline dynamics accurately. Introducing small temporal and spatial shifts in the comparison yields adequate agreement during the entire rundown process. Highly resolved numerical solutions are used to study physical variables that are not measured in laboratory experiments (e.g. pressure field and bottom shear stress). It is shown that the main mechanism for vortex shedding is correlated with the large pressure gradient along the slope as the rundown flow transitions from supercritical to subcritical, under the developing hydraulic jump. Furthermore, the bottom shear stress analysis indicates that the largest values occur at the shoreline and that the relatively large bottom shear stress also takes place within the supercritical flow region, being associated with the backwash vortex system rather than the plunging wave. It is clearly demonstrated that the combination of laboratory observations and numerical simulations have indeed provided significant insights into the swash flow processes.

Background: Recruiting family physicians into primary care research studies requires researchers to continually manage information coming in, going out, and coming in again. In many research groups, Microsoft Excel and Access are the usual data management tools, but they are very basic and do not support any automation, linking, or reminder systems to manage and integrate recruitment information and processes. Objective: We explored whether a commercial customer relationship management (CRM) software program – designed for sales people in businesses to improve customer relations and communications – could be used to make the research recruitment system faster, more effective, and more efficient. Findings: We found that while there was potential for long-term studies, it simply did not adapt effectively enough for our shorter study and recruitment budget. The amount of training required to master the software and our need for ongoing flexible and timely support were greater than the benefit of using CRM software for our study.