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We apply two methods to estimate the 21-cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly spaced triangles of antenna tiles, as well as an estimate based on data gridded to the uv-plane. The direct and gridded bispectrum estimators are applied to 21 h of high-band (167–197 MHz; z = 6.2–7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point-source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 h, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21-cm bispectrum may be accessible in less time than the 21-cm power spectrum for some wave modes, with detections in hundreds of hours.
In lifecourse studies that encompass the adolescent period, the assessment of pubertal status is important, but can be challenging. We aimed to identify current methods for pubertal assessment and assess their appropriateness for population-based research by combining a review of the literature with the views of experts in the field. We searched bibliographic databases, extracted data and assessed study quality to inform a workshop with 21 experts. Acceptability of different approaches was explored with a panel of ten adolescents. We screened 11,935 abstracts, assessed 157 articles and summarised results from 38 articles. Combining these with the opinions of experts, self-assessment was found to be a practical method for use in studies where agreement with the gold standard of clinical assessment by physical examination to within one Tanner stage was acceptable. Serial measures of height and foot size accurately indicated timing of the pubertal growth spurt and age at peak height velocity, and were seen as feasible within longitudinal studies. Hormonal and radiological methods did not offer a practical means of assessing pubertal status. Assessment of voice maturation was promising, but needed validation. Young people thought that self-assessment, foot size and voice assessments were acceptable, and preferred an assessor of the same sex for clinical assessment. This review thus informs researchers working in lifecourse and adolescent health, and identifies future directions in order to improve validity of the methods.
Use of personal mobile devices to record patient data appears to be increasing, but remains poorly studied. We sought to determine the extent and reasons that Canadian emergency physicians (EPs) and emergency medicine residents use personal mobile devices to record patient data in the emergency department (ED).
A national survey was distributed to Canadian EPs and residents between 27/02/17 and 23/03/17. This captured demographics, frequency, and purpose of personal mobile device use to record patient data in the ED. It also asked about obtaining consent, security of information, implications for patient care, and knowledge of relevant regulations.
The response rate was 23.1% (406 participants). A third (31.5%) reported using personal mobile devices to record patient data. Most (78.1%) did so more than once a month, and 7.0% did so every shift. Reasons cited included beliefs that using personal mobile devices to record patient data improves care by consultants (36.7%), expedites care (31.3%), and advances medical education (32.8%). Consent was rarely or never documented and a minority of participants (10.9%) indicated they did not obtain consent. More than half of participants (53.2%) reported being unaware of applicable regulations.
This is the first Canadian study on the use of personal mobile devices to record patient data in the ED. Our findings demonstrate current practice may risk privacy breaches. Personal mobile device use to record patient data in the ED is common and Canadian EPs and residents believe that this practice enhances patient care.
A common property regime was established at the founding of the Maya site of Actuncan, Belize, in the Terminal Preclassic period (175 BC–AD 300), which governed access to land until the Terminal Classic period (AD 780–1000). This interpretation is based on urban settlement patterns documented through household excavation and remote-sensing programs. Excavations of all visible patio-focused groups in the urban core provided data to reconstruct residential histories, and a 60,621 m2 gradiometer survey resulted in a magnetic gradient map that was used to document buried constructions. Twenty ground-truth testpits correlated types of magnetic signatures to buried patio-focused groups and smaller constructions, including walled plots in agricultural field systems that were later exposed more fully through large-scale excavations. Combined, these methods provided data to reconstruct four correlates of land tenure systems: (1) the spatial proximity of residential units to land and resources, (2) diachronic changes in community settlement patterns, (3) land subdivision and improvements, and (4) public goods. Spatial analyses documented that houselots did not cluster through time, but instead became gradually improved, lending evidence to suggest the transgenerational inheritance of property rights in the Late and Terminal Classic periods.
The GaLactic and Extragalactic All-sky Murchison Widefield Array survey is a radio continuum survey at 72–231 MHz of the whole sky south of declination +30º, carried out with the Murchison Widefield Array. In this paper, we derive source counts from the GaLactic and Extragalactic All-sky Murchison data at 200, 154, 118, and 88 MHz, to a flux density limit of 50, 80, 120, and 290 mJy respectively, correcting for ionospheric smearing, incompleteness and source blending. These counts are more accurate than other counts in the literature at similar frequencies as a result of the large area of sky covered and this survey’s sensitivity to extended emission missed by other surveys. At S154 MHz > 0.5 Jy, there is no evidence of flattening in the average spectral index (α ≈ −0.8 where S ∝ vα) towards the lower frequencies. We demonstrate that the Square Kilometre Array Design Study model by Wilman et al. significantly underpredicts the observed 154-MHz GaLactic and Extragalactic All-sky Murchison counts, particularly at the bright end. Using deeper Low-Frequency Array counts and the Square Kilometre Array Design Study model, we find that sidelobe confusion dominates the thermal noise and classical confusion at v ≳ 100 MHz due to both the limited CLEANing depth and the undeconvolved sources outside the field-of-view. We show that we can approach the theoretical noise limit using a more efficient and automated CLEAN algorithm.
We provide the first in situ measurements of antenna element beam shapes of the Murchison Widefield Array. Most current processing pipelines use an assumed beam shape, which can cause absolute and relative flux density errors and polarisation ‘leakage’. Understanding the primary beam is then of paramount importance, especially for sensitive experiments such as a measurement of the 21-cm line from the epoch of reionisation, where the calibration requirements are so extreme that tile to tile beam variations may affect our ability to make a detection. Measuring the primary beam shape from visibilities is challenging, as multiple instrumental, atmospheric, and astrophysical factors contribute to uncertainties in the data. Building on the methods of Neben et al. [Radio Sci., 50, 614], we tap directly into the receiving elements of the telescope before any digitisation or correlation of the signal. Using ORBCOMM satellite passes we are able to produce all-sky maps for four separate tiles in the XX polarisation. We find good agreement with the beam model of Sokolowski et al. [2017, PASA, 34, e062], and clearly observe the effects of a missing dipole from a tile in one of our beam maps. We end by motivating and outlining additional on-site experiments.
The low-frequency polarisation properties of radio sources are poorly studied, particularly in statistical samples. However, the new generation of low-frequency telescopes, such as the Murchison Widefield Array (the precursor for the low-frequency component of the Square Kilometre Array) offers an opportunity to probe the physics of radio sources at very low radio frequencies. In this paper, we present a catalogue of linearly polarised sources detected at 216 MHz, using data from the Galactic and Extragalactic All-sky Murchison Widefield Array survey. Our catalogue covers the Declination range –17° to –37° and 24 h in Right Ascension, at a resolution of around 3 arcminutes. We detect 81 sources (including both a known pulsar and a new pulsar candidate) with linearly polarised flux densities in excess of 18 mJy across a survey area of approximately 6 400 deg2, corresponding to a surface density of 1 source per 79 deg2. The level of Faraday rotation measured for our sources is broadly consistent with those recovered at higher frequencies, with typically more than an order of magnitude improvement in the uncertainty compared to higher-frequency measurements. However, our catalogue is likely incomplete at low Faraday rotation measures, due to our practice of excluding sources in the region where instrumental leakage appears. The majority of sources exhibit significant depolarisation compared to higher frequencies; however, a small sub-sample repolarise at 216 MHz. We also discuss the polarisation properties of four nearby, large-angular-scale radio galaxies, with a particular focus on the giant radio galaxy ESO 422–G028, in order to explain the striking differences in polarised morphology between 216 MHz and 1.4 GHz.
We describe the motivation and design details of the ‘Phase II’ upgrade of the Murchison Widefield Array radio telescope. The expansion doubles to 256 the number of antenna tiles deployed in the array. The new antenna tiles enhance the capabilities of the Murchison Widefield Array in several key science areas. Seventy-two of the new tiles are deployed in a regular configuration near the existing array core. These new tiles enhance the surface brightness sensitivity of the array and will improve the ability of the Murchison Widefield Array to estimate the slope of the Epoch of Reionisation power spectrum by a factor of ∼3.5. The remaining 56 tiles are deployed on long baselines, doubling the maximum baseline of the array and improving the array u, v coverage. The improved imaging capabilities will provide an order of magnitude improvement in the noise floor of Murchison Widefield Array continuum images. The upgrade retains all of the features that have underpinned the Murchison Widefield Array’s success (large field of view, snapshot image quality, and pointing agility) and boosts the scientific potential with enhanced imaging capabilities and by enabling new calibration strategies.
Despite many interventions aiming to reduce excessive gestational weight gain (GWG), it is currently unclear the impact on infant anthropometric outcomes. The aim of this review was to evaluate offspring anthropometric outcomes in studies designed to reduce GWG. A systematic search of seven international databases, one clinical trial registry and three Chinese databases was conducted without date limits. Studies were categorised by intervention type: diet, physical activity (PA), lifestyle (diet + PA), other, gestational diabetes mellitus (GDM) (diet, PA, lifestyle, metformin and other). Meta-analyses were reported as weighted mean difference (WMD) for birthweight and birth length, and risk ratio (RR) for small for gestational age (SGA), large for gestational age (LGA), macrosomia and low birth weight (LBW). Collectively, interventions reduced birthweight, risk of macrosomia and LGA by 71 g (WMD: −70.67, 95% CI −101.90 to −39.43, P<0.001), 16% (RR: 0.84, 95% CI 0.73–0.98, P=0.026) and 19% (RR: 0.81, 95% CI 0.69–0.96, P=0.015), respectively. Diet interventions decreased birthweight and LGA by 99 g (WMD −98.80, 95% CI −178.85 to −18.76, P=0.016) and 65% (RR: 0.35, 95% CI 0.17–0.72, P=0.004). PA interventions reduced the risk of macrosomia by 51% (RR: 0.49, 95% CI 0.26–0.92, P=0.036). In women with GDM, diet and lifestyle interventions reduced birthweight by 211 and 296 g, respectively (WMD: −210.93, 95% CI −374.77 to −46.71, P=0.012 and WMD:−295.93, 95% CI −501.76 to −90.10, P=0.005, respectively). Interventions designed to reduce excessive GWG lead to a small reduction in infant birthweight and risk of macrosomia and LGA, without influencing the risk of adverse outcomes including LBW and SGA.
Nasal disease imposes a significant disease burden upon the individual in the general population, but is relatively under studied in athletes. This study sought to define the frequency of nasal symptoms in the active population, and to quantify the impact of these symptoms on quality of life and on the frequency of upper respiratory tract infections.
A total of 296 participants completed the study (246 athletes and 50 sedentary controls). Nasal symptoms were significantly more frequent in the active group than in the sedentary controls (70 per cent vs 52 per cent). Upper respiratory tract infections were significantly more common in athletes with regular nasal symptoms than in athletes without nasal symptoms. Quality-of-life scores, as measured by the 22-item Sino-Nasal Outcome Test, were significantly worse in athletes with regular nasal symptoms.
This study suggests that regular exercise is associated with a significant increase in the prevalence of troubling nasal symptoms, and nasal symptoms in athletes are associated with increased susceptibility to upper respiratory tract infections. Quality of life was negatively affected, confirming the importance of nasal health to athlete welfare.
It is important to pay attention to weight management before and between pregnancies, as women have an increased risk of weight gain during the reproductive years. Having a baby is a life-changing event for women and the challenge of weight management amidst this period of major physiological, psychological and social change should not be underestimated. However, the postpartum period offers an opportune time for lifestyle interventions, as women may have heightened awareness of their own and their wider families’ health. Systematic reviews indicate that interventions including both diet and physical activity along with individualised support and self-monitoring are more likely to be successful in promoting postpartum weight loss. However, high levels of attrition and poor engagement have been an issue in previous trials in this area. Since postpartum women are difficult to reach and retain, future research must consider how to make weight-management interventions an attractive and attainable proposition for women who are juggling multiple, competing demands on their time. Ideally, intervention approaches need to be flexible and allow sustained contact with women, to facilitate a focus on maintenance of weight loss, as well as opportunities for re-engagement after life events that may disrupt weight-management progress. Using technology to deliver or support interventions holds promise but trials are needed to generate a range of appealing, effective and scalable options for postpartum women. What works at other life stages may not necessarily work here owing to specific barriers to weight management encountered in the postpartum period.
Increasing the representation of women in science, technology, engineering, and mathematics (STEM) is one of our nation's most pressing imperatives. As such, there has been increased lay and scholarly attention given to understanding the causes of women's underrepresentation in such fields. These explanations tend to fall into two main groupings: individual-level (i.e., her) explanations and social-structural (i.e., our) explanations. These two perspectives offer different lenses for illuminating the causes of gender inequity in STEM and point to different mechanisms by which to gain gender parity in STEM fields. In this article, we describe these two lenses and provide three examples of how each lens may differentially explain gender inequity in STEM. We argue that the social-structural lens provides a clearer picture of the causes of gender inequity in STEM, including how gaining gender equity in STEM may best be achieved. We then make a call to industrial/organizational psychologists to take a lead in addressing the societal-level causes of gender inequality in STEM.
Introduction: The use of personal mobile devices to record patient data appears to be increasing, but remains poorly studied. We sought to determine the magnitude and purposes for which Canadian emergency physicians (EPs) and residents use their personal mobile devices (PMDs) to record patient data in the emergency department (ED). Methods: An anonymous survey was distributed to EPs and residents in the Canadian Association of Emergency Physicians (CAEP) database between 27/02/17 and 23/03/17. The survey captured demographic information and information on frequency and purpose of PMD use in the ED, whether consent was obtained, how the information was secured, and any possible implications for patient care. Participants were also asked about knowledge of, and any perceived restrictions from, current regulations regarding the use of PMDs healthcare settings. Results: The survey response rate was 23.1%. Of 415 respondents, 9 surveys were rejected for incomplete demographic data, resulting in 406 participants. A third (31.5%, 128/406, 95% CI 27.0-36.3) reported using PMDs to record patient data. Most (78.1%) reported doing so more than once a month and 7.0% reported doing so once every shift. 10.9% of participants indicated they did not obtain written or verbal consent. Reasons cited by participants for using PMDs to record patient data included a belief that doing so improves care provided by consultants (36.7%), expedites patient care (31.3%), and improves medical education (32.8%). 53.2% of participants were unaware of current regulations and 19.7% reported feeling restricted by them. Subgroup analysis suggested an increased frequency of PMD use to record patient data among younger physicians and physicians in rural settings. Conclusion: This is the first known Canadian study on the use of PMDs to record patient data in the ED. Our results suggest that this practice is common, and arises from a belief that doing so enhances patient care through better communication, efficiency, and education. Our findings also suggest current practices result in risk of both privacy and confidentiality breaches, and thus support arguments for both physician education and regulation reform.
We report major new insights from recent research at the Powars II Paleoindian red ocher quarry (48PL330). We salvaged more than 7,000 artifacts from Powars II between 2014 and 2016 by screening redeposited sediment from the talus slope below the intact portion of the site. Clovis artifacts dominate the diagnostic artifact assemblage, including 53 Clovis points, 33 preforms, and artifacts associated with a previously unrecognized blade core industry. We report the first radiocarbon dates from the site, determined from dating bone tools, which indicate Cody-aged use (ca. >10,000 cal BP). Further, salvage efforts discovered a previously unknown toolstone source from which many of the Clovis artifacts were produced. The Powars II Clovis points most resemble early Paleoindian points from the far Northern Plains and were likely both produced and discarded in the red ocher quarry after hunting, as evidenced by preform production and the presence of impact fractures on many used points. Given these production and discard patterns, Powars II holds some of the best evidence archaeologists currently have for Paleoindian ritualism related to hunting.