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Cardiac intensivists frequently assess patient readiness to wean off mechanical ventilation with an extubation readiness trial despite it being no more effective than clinician judgement alone. We evaluated the utility of high-frequency physiologic data and machine learning for improving the prediction of extubation failure in children with cardiovascular disease.
This was a retrospective analysis of clinical registry data and streamed physiologic extubation readiness trial data from one paediatric cardiac ICU (12/2016-3/2018). We analysed patients’ final extubation readiness trial. Machine learning methods (classification and regression tree, Boosting, Random Forest) were performed using clinical/demographic data, physiologic data, and both datasets. Extubation failure was defined as reintubation within 48 hrs. Classifier performance was assessed on prediction accuracy and area under the receiver operating characteristic curve.
Of 178 episodes, 11.2% (N = 20) failed extubation. Using clinical/demographic data, our machine learning methods identified variables such as age, weight, height, and ventilation duration as being important in predicting extubation failure. Best classifier performance with this data was Boosting (prediction accuracy: 0.88; area under the receiver operating characteristic curve: 0.74). Using physiologic data, our machine learning methods found oxygen saturation extremes and descriptors of dynamic compliance, central venous pressure, and heart/respiratory rate to be of importance. The best classifier in this setting was Random Forest (prediction accuracy: 0.89; area under the receiver operating characteristic curve: 0.75). Combining both datasets produced classifiers highlighting the importance of physiologic variables in determining extubation failure, though predictive performance was not improved.
Physiologic variables not routinely scrutinised during extubation readiness trials were identified as potential extubation failure predictors. Larger analyses are necessary to investigate whether these markers can improve clinical decision-making.
A chloroacetamide herbicide by application timing factorial experiment was conducted in 2017 and 2018 in Mississippi to investigate chloroacetamide use in a dicamba-based Palmer amaranth management program in cotton production. Herbicides used were S-metolachlor or acetochlor, and application timings were preemergence, preemergence followed by (fb) early postemergence, preemergence fb late postemergence, early postemergence alone, late postemergence alone, and early postemergence fb late postemergence. Dicamba was included in all preemergence applications, and dicamba plus glyphosate was included with all postemergence applications. Differences in cotton and weed response due to chloroacetamide type were minimal, and cotton injury 14 d after LP application was less than 10% for all application timings. Late-season weed control was reduced up to 30 and 53% if chloroacetamide application occurred PRE or LP only, respectively. Late-season weed densities were minimized if multiple applications were used instead of a single application. Cotton height was reduced by up to 23% if a single application was made LP relative to other application timings. Chloroacetamide application at any timing except PRE alone minimized late season weed biomass. Yield was maximized by any treatment involving multiple applications or EP alone whereas applications PRE or LP alone resulted in up to 56 and 27% yield losses, respectively. While no yield loss was reported by delaying the first of sequential applications until EP, foregoing a PRE application is not advisable given the multiple factors that may delay timely POST applications such as inclement weather.
Incentivizing the development of interdisciplinary scientific teams to address significant societal challenges usually takes the form of pilot funding. However, while pilot funding is likely necessary, it is not sufficient for successful collaborations. Interdisciplinary collaborations are enhanced when team members acquire competencies that support team success.
We evaluated the impact of a multifaceted team development intervention that included an eight-session workshop spanning two half-days. The workshop employed multiple methods for team development, including lectures on empirically supported best practices, skills-based modules, role plays, hands-on planning sessions, and social interaction within and across teams. We evaluated the impact of the intervention by (1) asking participants to assess each of the workshop sessions and (2) by completing a pre/postquestionnaire that included variables such as readiness to collaborate, goal clarity, process clarity, role ambiguity, and behavioral trust.
The content of the team development intervention was very well received, particularly the workshop session focused on psychological safety. Comparison of survey scores before and after the team development intervention indicated that scores on readiness to collaborate and behavioral trust were significantly higher among participants who attended the workshop. Goal clarity, process clarity, and role ambiguity did not differ among those who attended versus those who did not.
Multicomponent team development interventions that focus on key competencies required for interdisciplinary teams can support attitudes and cognitions that the literature on the science of team science indicate are predictive of success. We offer recommendations for the design of future interventions.
The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia and will cover the full ASKAP band of 700–1800 MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey and Sydney University Molonglo Sky Survey radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with
15 arcsec resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination
made over a 288-MHz band centred at 887.5 MHz.
Breakthrough Listen is a 10-yr initiative to search for signatures of technologies created by extraterrestrial civilisations at radio and optical wavelengths. Here, we detail the digital data recording system deployed for Breakthrough Listen observations at the 64-m aperture CSIRO Parkes Telescope in New South Wales, Australia. The recording system currently implements two modes: a dual-polarisation, 1.125-GHz bandwidth mode for single-beam observations, and a 26-input, 308-MHz bandwidth mode for the 21-cm multibeam receiver. The system is also designed to support a 3-GHz single-beam mode for the forthcoming Parkes ultra-wideband feed. In this paper, we present details of the system architecture, provide an overview of hardware and software, and present initial performance results.
We have observed the Vela pulsar for 1 year using a Phased Array Feed (PAF) receiver on the 12-m antenna of the Parkes Test-Bed Facility (PTF). These observations have allowed us to investigate the stability of the PAF beam weights over time, to demonstrate that pulsars can be timed over long periods using PAF technology and to detect and study the most recent glitch event that occurred on 12 December 2016. The beam weights are shown to be stable to 1% on time scales on the order of three weeks.
We have observed the Vela pulsar for 1 year using a phased array feed receiver on the 12-m antenna of the Parkes Test-Bed Facility. These observations have allowed us to investigate the stability of the phased array feed beam weights over time, to demonstrate that pulsars can be timed over long periods using phased array feed technology and to detect and study the most recent glitch event that occurred on 2016 December 12. The beam weights are shown to be stable to 1% on time scales on the order of three weeks. We discuss the implications of this for monitoring pulsars using phased array feeds on single dish telescopes.
We present a list of bright (< 17 mag) southern QSOs and bright (< 11 mag) stars that may be suitable for the Hubble Space Telescope link between the Hipparcos astrometric reference frame and the VLBI extragalactic frame. The QSOs have been selected from various lists of radio objects and identifications. The stars have been selected from the Strasbourg (CDS) data base and from the Preliminary Second Cape Photographic Catalogue, and supplemented with stars measured from the SERC IIIa-J Schmidt survey. The list of QSOs and stars have been included in the Hipparcos and HST schedule of observations.
Following the ‘prompt’ radio outburst seen soon after the neutrino emission in SN 1987A (Turtle et al. 1987), we initiated a program to monitor the supernova at the Tidbinbilla Deep Space Communications Complex at 8.4 GHz in a search for radio emission from the expanding remnant. No radio emission has been detected to date (DOY 151, May 30 1988).
Conservation efforts use scientific data to provide an adaptive framework wherein habitat and wildlife sustainability can co-exist with human activities. Good science informs decision-makers and facilitates the development of successful conservation approaches. However, conservation concerns for the dugong Dugong dugon in South-east Asia are sufficiently urgent that action must be taken quickly, even though science has not provided complete answers to critical questions. In Johor, Malaysia, aerial surveys were conducted to assess dugong numbers, dugong high-use areas and overlap of dugong sightings with areas of seagrass. Dugong distribution included existing marine parks and locations where known conservation threats exist. We conclude that the Johor islands may represent a significant congregation site for dugongs in Peninsular Malaysia, with as many as 20 dugongs recorded in a single day. The existence of a marine park where the dugong sightings were most prominent is encouraging but only 38% of those sightings fell within the boundaries of the park. Anthropogenic threats need to be assessed and addressed prior to complex development activities such as dredging and coastal reclamation for tourism development in this critical area. We use this case to explore the concept of advancing species conservation through focused research and management, particularly where uncertainties exist because data are scarce.
We report the results of a successful 7-hour 1.4 GHz Very Long Baseline Interferometry (VLBI) experiment using two new stations, ASKAP-29 located in Western Australia and WARK12M located on the North Island of New Zealand. This was the first geodetic VLBI observing session with the participation of these new stations. We have determined the positions of ASKAP-29 and WARK12M. Random errors on position estimates are 150–200 mm for the vertical component and 40–50 mm for the horizontal component. Systematic errors caused by the unmodeled ionosphere path delay may reach 1.3 m for the vertical component.
A full appreciation of the ecology and conservation of the Sirenia requires an understanding of their evolutionary history. Modern manatees and dugongs provide only a limited view of a much deeper biological continuum that extends back over 50 million years. There were numerous branchings along this continuum: dozens of species of sirenians existed through time. They ranged in size from little sea cows perhaps 150 kg in body mass, to the largest mammal other than the great whales to exist in historic time – Steller’s sea cow – at a plausible body mass of over 10 000 kg (Chapter 2). Early sirenians walked on land with sturdy hind limbs, but fed on aquatic vegetation. Later forms were fully aquatic, with a variety of foraging strategies: some ate delicate seagrass leaves, some had large and powerful tusks that dug or cut through tough seagrass rhizomes, some may have specialised on molluscs, and others had no teeth at all and fed on soft kelps higher in the water column. These sirenians prospered or became extinct according to shifting climatic, geologic, oceanographic and biological conditions. Unlike the very rapidly changing environmental conditions of today that are products of human population and technological growth, varying conditions of the past acted more slowly, allowing ancient sirenians to adapt and evolve altered modes of life.
In this chapter we summarise this evolutionary history. We begin with two essential questions that have long fascinated scholars of the Sirenia: what were their ancestors like, and who are their closest living relatives? First, we briefly review the history of morphological and palaeontological studies of these questions, and how the hypothesised affinities have been reflected in the placement of the Sirenia in various mammalian classification schemes. Then we summarise the explosion of molecular and genetic data that have forced some radical reinterpretations of the evolutionary history of mammals within the past decade, concentrating on how these new data relate to the Sirenia and their closest affinities.
This book was born out of passion, frustration, excitement and hope. Readers will perceive all these emotions throughout the following pages. If the hard-won lessons recounted here lead to improved conservation of some remarkable species and their ecosystems, we will have fulfilled our aim.
We have cumulatively spent well over a century studying the various members of the Order Sirenia. Our passions include learning about and trying to conserve manatees and dugongs. The word ‘unique’ has lost its force through inaccuracy and over-use, but we want to reclaim its original meaning here. The sirenians possess suites of morphological, ecological and physiological adaptations that allow them, truly, to hold a unique place in the animal kingdom. Although once a more diverse group, the sirenians are limited now to only four species, albeit with remarkably wide geographic ranges (especially the dugong). Reduced in numbers through much of that range, and with myriad threats to their long-term survival, the sirenians have nonetheless demonstrated tenacity and resilience, hopeful signs that they will persist, if given a chance.
As explained in Chapter 3, sirenians evolved from primitive terrestrial herbivores early in the Tertiary period. Like whales and dolphins (cetaceans) but unlike the pinnipeds (walruses, seals and sea lions), manatees and dugongs spend their entire lives in the water and do not return to land to give birth and suckle their young. Sirenians are believed to share a common origin with several superficially dissimilar mammals of African origin, grouped together at the superordinal level as the Afrotheria. Within the Afrotheria the sirenians are closely aligned with elephants and hyraxes, and the three have been linked together as the clade Paenungulata, a unique grouping recognised for most of the last century (see Chapter 3). Although features of the external form of sirenians reflect adaptations to their lives of swimming and diving, the phylogenetic history of dugongs and manatees is reflected in features of their reproductive biology, which in some respects is strikingly similar to that of elephants (as outlined under ‘Reproductive cycles’ below and in the Supplementary Material Appendix 6.1).
Understanding the life history and reproductive biology of sirenians is fundamental to the development of effective strategies for their conservation. For example, knowledge of when and where they breed is important for assessing the effectiveness of establishing sanctuaries or other protected areas to protect breeding habitat. In addition, knowledge of the mating system (Chapter 5), the average ages at which females start breeding, the litter size, average inter-birth interval, life span and the probabilities of reproduction and survival, and how these parameters are affected by age and changing environmental conditions, are essential for understanding the population dynamics of manatees and dugongs. Knowledge of population dynamics is a requisite for sound management policies and for estimating the levels of human-induced mortality that are likely to be sustainable. In this chapter, we characterise the biology of reproduction in the Sirenia, and describe the methodological and analytical approaches that have been taken over the years to determine their vital parameters of reproduction and survival. We summarise the results of these studies and then review how information about vital parameters has been incorporated into models of sirenian population dynamics and the implications of these models for future research and management.