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We describe the design and performance of the Engineering Development Array, which is a low-frequency radio telescope comprising 256 dual-polarisation dipole antennas working as a phased array. The Engineering Development Array was conceived of, developed, and deployed in just 18 months via re-use of Square Kilometre Array precursor technology and expertise, specifically from the Murchison Widefield Array radio telescope. Using drift scans and a model for the sky brightness temperature at low frequencies, we have derived the Engineering Development Array’s receiver temperature as a function of frequency. The Engineering Development Array is shown to be sky-noise limited over most of the frequency range measured between 60 and 240 MHz. By using the Engineering Development Array in interferometric mode with the Murchison Widefield Array, we used calibrated visibilities to measure the absolute sensitivity of the array. The measured array sensitivity matches very well with a model based on the array layout and measured receiver temperature. The results demonstrate the practicality and feasibility of using Murchison Widefield Array-style precursor technology for Square Kilometre Array-scale stations. The modular architecture of the Engineering Development Array allows upgrades to the array to be rolled out in a staged approach. Future improvements to the Engineering Development Array include replacing the second stage beamformer with a fully digital system, and to transition to using RF-over-fibre for the signal output from first stage beamformers.
Improving children's learning and development in conflict-affected countries is critically important for breaking the intergenerational transmission of violence and poverty. Yet there is currently a stunning lack of rigorous evidence as to whether and how programs to improve learning and development in conflict-affected countries actually work to bolster children's academic learning and socioemotional development. This study tests a theory of change derived from the fields of developmental psychopathology and social ecology about how a school-based universal socioemotional learning program, the International Rescue Committee's Learning to Read in a Healing Classroom (LRHC), impacts children's learning and development. The study was implemented in three conflict-affected provinces of the Democratic Republic of the Congo and employed a cluster-randomized waitlist control design to estimate impact. Using multilevel structural equation modeling techniques, we found support for the central pathways in the LRHC theory of change. Specifically, we found that LRHC differentially impacted dimensions of the quality of the school and classroom environment at the end of the first year of the intervention, and that in turn these dimensions of quality were differentially associated with child academic and socioemotional outcomes. Future implications and directions are discussed.
Objectives: To summarize the clinical characteristics and outcomes of pediatric sports-related concussion (SRC) patients who were evaluated and managed at a multidisciplinary pediatric concussion program and examine the healthcare resources and personnel required to meet the needs of this patient population. Methods: We conducted a retrospective review of all pediatric SRC patients referred to the Pan Am Concussion Program from September 1st, 2013 to May 25th, 2015. Initial assessments and diagnoses were carried out by a single neurosurgeon. Return-to-Play decision-making was carried out by the multidisciplinary team. Results: 604 patients, including 423 pediatric SRC patients were evaluated at the Pan Am Concussion Program during the study period. The mean age of study patients was 14.30 years (SD: 2.32, range 7-19 years); 252 (59.57%) were males. Hockey (182; 43.03%) and soccer (60; 14.18%) were the most commonly played sports at the time of injury. Overall, 294 (69.50%) of SRC patients met the clinical criteria for concussion recovery, while 75 (17.73%) were lost to follow-up, and 53 (12.53%) remained in active treatment at the end of the study period. The median duration of symptoms among the 261 acute SRC patients with complete follow-up was 23 days (IQR: 15, 36). Overall, 25.30% of pediatric SRC patients underwent at least one diagnostic imaging test and 32.62% received referral to another member of our multidisciplinary clinical team. Conclusion: Comprehensive care of pediatric SRC patients requires access to appropriate diagnostic resources and the multidisciplinary collaboration of experts with national and provincially-recognized training in TBI.
Levels of pollution, including contamination by toxic metals, in the Thames estuary reduced over the last four decades of the 20th century. This 2014 study investigates whether the declines in the bioavailabilities of trace metals (Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) have continued in the 21st century, using a suite of littoral biomonitors also employed in 2001 – the brown seaweed Fucus vesiculosus, the strandline, talitrid amphipod Orchestia gammarellus and the estuarine barnacle Amphibalanus improvisus. Bioaccumulated concentrations represent relative measures of the total bioavailabilities of each metal to the biomonitor over a previous time period, and can be compared over space and over time. Trace metal bioavailabilities varied along the estuary, and, in general, fell between 2001 and 2014, a reflection of the continuing remediation of the Thames estuary from its severely polluted state in the middle of the 20th century.
We present the results of an approximately 6 100 deg2 104–196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, − 58° < Dec < −14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6–3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam− 1, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14 110 sources, extracted from the mosaic, 1 247 of which are sub-components of complexes of sources.
Rectal colonization with multidrug-resistant Enterobacteriaceae was found in 23 of 94 consecutively enrolled international patients hospitalized at Mayo Clinic, Rochester, Minnesota. No carbapenemase producers were detected. Twenty-one isolates were extended-spectrum β-lactamase-producing Escherichia coli. Colonization was associated with gastrointestinal disease and central venous catheter placement within the antecedent year.
Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the southern hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 MHz with arcminute angular resolution and high survey efficiency. The telescope will enable new advances along four key science themes, including searching for redshifted 21-cm emission from the EoR in the early Universe; Galactic and extragalactic all-sky southern hemisphere surveys; time-domain astrophysics; and solar, heliospheric, and ionospheric science and space weather. The Murchison Widefield Array is located in Western Australia at the site of the planned Square Kilometre Array (SKA) low-band telescope and is the only low-frequency SKA precursor facility. In this paper, we review the performance properties of the Murchison Widefield Array and describe its primary scientific objectives.
To determine prevalence, predictors, and outcomes of infection due to Escherichia coli sequence type ST131.
All healthcare settings in Olmsted County, Minnesota (eg, community hospital, tertiary care center, long-term care facilities, and ambulatory clinics).
Ambulatory and hospitalized children and adults with extraintestinal E. coli isolates.
We analyzed 299 consecutive, nonduplicate extraintestinal E. coli isolates submitted to Olmsted County laboratories in February and March 2011. ST131 was identified using single-nucleotide polymorphism polymerase chain reaction and further evaluated through pulsed-field gel electrophoresis. Associated clinical data were abstracted through medical record review.
Most isolates were from urine specimens (90%), outpatients (68%), and community-associated infections (61%). ST131 accounted for 27% of isolates overall and for a larger proportion of those isolates resistant to fluoroquinolones (81%), trimethoprim-sulfamethoxazole (42%), gentamicin (79%), and ceftriaxone (50%). The prevalence of ST131 increased with age (accounting for 5% of isolates from those 11–20 years of age, 26% of isolates from those 51–60 years of age, and 50% of isolates from those 91–100 years of age). ST131 accounted for a greater proportion of healthcare-associated isolates (49%) than community-associated isolates (15%) and for fully 76% of E. coli isolates from long-term care facility (LTCF) residents. Multivariable predictors of ST131 carriage included older age, LTCF residence, previous urinary tract infection, high-complexity infection, and previous use of fluoroquinolones, macrolides, and extended-spectrum cephalosporins. With multivariable adjustment, ST131-associated infection outcomes included receipt of more than 1 antibiotic (odds ratio [OR], 2.54 [95% confidence interval (CI), 1.25–5.17]) and persistent or recurrent symptoms (OR, 2.53 [95% CI, 1.08–5.96]). Two globally predominant ST131 pulsotypes accounted for 45% of STB 1 isolates.
ST131isa dominant, antimicrobial-resistant clonal group associated with healthcare settings, elderly hosts, and persistent or recurrent symptoms.
We summarise the proceedings of a workshop on ‘Supernova Remnants, Pulsars and the Interstellar Medium’ which was held at the Special Research Centre for Theoretical Astrophysics at the University of Sydney on 18 and 19 March 1999.
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae, and orphan afterglows of gamma-ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of 5 s and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.
Exploring the cell-material interface is an emerging area of great interest in biomaterial science. Specifically, creating nanostructured surface interfaces to improve biomaterial efficacy is one of these key focus topics. As an example, an increasing number of studies have demonstrated the positive role nanostructured surfaces can have towards promoting various cell functions. However, the relevant mechanism behind this improvement in biological interactions at the cell-implant interface is not well understood. For this reason, here, osteoblast (bone forming cells) and fibroblast (fibrous, soft tissue forming cells) functions (including adhesion and proliferation) on two carefully fabricated diamond films with dramatically different topographies were tested. The results revealed greater cell responses on nanocrystalline diamond (grain sizes <100nm) compared to submicron crystalline diamond (grain sizes 200˜1000nm). In order to understand this positive impact of diamond nanotopography on cell responses, fibronectin absorption and subsequent cell spreading were studied. More importantly, cell filopodia extensions were also studied through computational mechanical modeling. A deflection-diffusion model of cell filopodia extension was established and clearly suggested that increasing the lateral dimension or height of nanometer surface features could inhibit cell filopodia extension and decrease cell spreading. Both the experiments and modeling from this study indicated that a nanometer surface topography can enhance cell responses to promote implant efficacy.
The condition or syndrome to be considered in this monograph has been a clearly recognized clinical entity since the descriptions given by Quincke (1893, 1897) and Nonne (1904, 1914) over 100 years ago. However, reports of cases which were almost certainly examples of the same condition undoubtedly antedated their pioneering accounts by almost four decades. The essential elements of the syndrome are the symptoms and signs of intracranial hypertension without ventricular dilatation and without an intracranial mass lesion. For reasons which will be made clear in the following chapters, we shall call it the pseudotumor cerebri syndrome (PTCS) although quite a variety of terms have been applied to it. It is a particularly intriguing condition for a number of reasons, as follows:
Clinically the condition presents an essentially pure picture of raised intracranial pressure (ICP) without focal neurological disturbance and without investigative evidence of structural disturbance, either focal or general. As such, it is a condition which manifests, in isolation, what is a critical component of many neurological and neurosurgical conditions, i.e. intracranial hypertension, thereby creating a situation in which the pathological effects of this component exist in a pure form.
Despite much speculation and numerous clinical and laboratory studies (although clinical investigations are constrained by the exigent circumstances of the condition and laboratory studies by lack of a suitable model) there is still no clear consensus on its mechanism, although the predominant view is that the intracranial hypertension is due to a disturbance of cerebrospinal fluid (CSF) dynamics.
Whilst this subject has, in part, been considered in the previous chapter on treatment, there are several aspects pertaining to outcome which merit separate and particular consideration. These aspects, which include duration of symptoms, the outcome for visual function, the likelihood of recurrence, psychological sequelae and the development of other diseases (this last incorporating the risk of error in the initial diagnosis), will be addressed in turn in the present chapter. In each instance the data from the Glasgow and Sydney series will be given, followed by a review of the relevant literature.
Duration of symptoms and signs
In Table 9.1 the patients in the Glasgow series are divided according to whether an aetiological factor was identified or not. In neither group did symptoms persist for long after the start of treatment in the majority of cases. Thus, in 83 of the 99 patients (83.8%) initially complaining of headache and 69 of the 88 patients (78.4%) with visual symptoms at the time of presentation, symptoms had cleared within 3 months of starting treatment. Headaches persisted longer than 12 months in only seven patients (7.1%), and visual symptoms in only 10 patients (11.4%). The duration of papilloedema tended to be longer, however, persisting for between 4 and 12 months in 38 of 92 patients (41.3%), and for longer than 12 months in 14 of 92 patients (15.2%).
The condition known most widely as pseudotumor cerebri syndrome is of diagnostic interest and clinical importance not just to neurosurgeons, but also to neurologists, ophthalmologists and headache specialists. Variously called idiopathic intracranial hypertension, benign intracranial hypertension, and other names over the century or so since it was first recognised, the authors argue for the grouping of all these conditions under the name of pseudotumor cerebri syndrome on the basis of a common underlying mechanism - an impairment of CSF absorption due to abnormalities at the CSF/venous interface. The book reviews the development of ideas around some of the more contentious issues and deals in depth with aetiology, investigative findings and strategies, treatment and outcome, and in the concluding chapter, considers the possibility of establishing an experimental model to facilitate analysis of the unresolved issues, and pointing the way to a more complete understanding of this controversial condition.