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This study evaluates the morbidity, mortality, and cost differences between patients who underwent either a simple or a complex arterial switch operation.
A retrospective study of patients undergoing an arterial switch operation at a single institution was performed. Simple cases were defined as patients with d-transposition of the great arteries with usual coronary anatomy or circumflex artery originating from the right with either intact ventricular septum or ventricular septal defect. Complex cases included all other forms of coronary anatomy, aortic coarctation or arch hypoplasia, and Taussig–Bing anomalies. Costs were acquired using an institutional activity-based accounting system.
A total of 98 patients were identified, 68 patients in the simple group and 30 in the complex group. The mortality rate was 2% for the simple and 7% for the complex group, p=0.23. Major morbidities including cardiac arrest, extracorporeal membrane oxygenation, a major coronary event, surgical or catheter-based re-intervention, stroke, or permanent pacemaker placement, non-cardiac surgical procedures, mediastinitis, and sepsis did not differ between the simple and complex groups (16 versus 27%, p=0.16). The complex group had increased bleeding requiring re-exploration (0 versus 10%, p=0.04). Hospital and ICU length of stay did not differ. Complex patients had higher overall hospital costs (simple $80,749 versus complex $97,387, p=0.01) and higher postoperative costs (simple $60,192 versus complex $70,132, p=0.02). The operating room and supplies accounted for the majority of the cost difference.
Complex arterial switches can be safely performed with low rates of morbidity and mortality but at an increased cost.
We describe the performance of the Boolardy Engineering Test Array, the prototype for the Australian Square Kilometre Array Pathfinder telescope. Boolardy Engineering Test Array is the first aperture synthesis radio telescope to use phased array feed technology, giving it the ability to electronically form up to nine dual-polarisation beams. We report the methods developed for forming and measuring the beams, and the adaptations that have been made to the traditional calibration and imaging procedures in order to allow BETA to function as a multi-beam aperture synthesis telescope. We describe the commissioning of the instrument and present details of Boolardy Engineering Test Array’s performance: sensitivity, beam characteristics, polarimetric properties, and image quality. We summarise the astronomical science that it has produced and draw lessons from operating Boolardy Engineering Test Array that will be relevant to the commissioning and operation of the final Australian Square Kilometre Array Path telescope.
The Cycadales are a group of significant global conservation concern and have the highest extinction risk of all seed plants. Understanding the synchronisation of reproductive phenology of Cycadales may be useful for conservation by enabling the targeting of pollen and seed collection from wild populations and identifying the window of fertilisation to aid in the cultivation of Cycadales. Phenological data for 11 species of Zamia were gathered from herbarium specimens. Four phenological characters were coded with monthly character states. DNA was isolated and sequenced for 26S, CAB, NEEDLY, matK and rbcL, and a simultaneous phylogenetic analysis of phenology and DNA sequence data was carried out. Three major clades were recovered: a Caribbean clade, a Central American clade and a South American clade. Eight species showed statistically significant synchronisation in microsporangiate and ovulate phenological phases, indicating the time of fertilisation. Close reproductive synchronisation was consistently observed throughout the Caribbean clade (statistically significant in four of five species) but was less consistent in the Central American clade (statistically significant in one of two species) and South American clade (statistically significant in three of four species). Ultimately, phenology is shown to be a potential driver of speciation in some clades of Zamia and in others to be a potential barrier to hybridisation.
We summarise the first year of operation of the Medium Deep Survey - a key project of the HST. Two fields in the LMC are discussed and some preliminary scientific results presented. We also comment on image deconvolution for the extragalactic fields observed as part of the Medium Deep Survey.
It came as a great surprise that many dwarf elliptical galaxies of very low surface brightness in the Virgo Cluster have conspicuous bright star-like nuclei (Reaves 1983, Binggeli, Sandage and Tammann 1985). These nuclei are at least a factor of 10 more luminous than the brightest globular clusters in the Local Group and comparable only to the very brightest globulars surrounding M87. They contain a considerable fraction (1 to 20%) of the total light of the parent galaxy (Binggeli, priv. commun.). Their physical nature and origin are a matter of debate (Zinnecker et al. 1985, van den Bergh 1985, Norman 1986, Zinnecker 1986) but optical spectroscopy for 3 objects indicates a stellar composition with a range similar to globular clusters (Bothun et al. 1985). It has been suggested that a central nucleus is formed when off-center bound star clusters migrate to the center as a consequence of dynamical friction (Norman 1986). Support for such a scenario comes from CCD observations of IC 3475 which reveal numerous knots near the center of this dwarf irregular galaxy (Vigroux et al. 1986). These knots have the same color as the parent galaxy and are interpreted as intermediate age star clusters.
This small cluster is situated in the western region of the SMC at α = 0h 26m 13s, ε = −73°, 1′, 20″ (1950) and has been chosen for study in the initial post-launch period of the Hubble Space Telescope. This preliminary study was made using data obtained using a CCD camera on the SAAO 1 m telescope in October 1984.
This paper presents a color magnitude diagram for the enigmatic cluster ω Centauri (NGC 5139 = C1328 − 472) tracing the main sequence down to V ~ 21.5. The spread in color on the upper main sequence is confirmed as intrinsic to the cluster. The CCD observations were made using the SAAO 1 m telescope with the UCL CCD camera and the RGO CCD camera at the prime focus of the AAT.
With HST and WFPC2, galaxies in the Medium Deep Survey can be reliably classified to magnitudes I814 ≲ 22.0 in the F814W band, at a mean redshift . The main result is the relatively high proportion (~40%) of objects which are in some way irregular or anomalous, and which are of relevance in understanding the origin of the familiar excess population of faint galaxies. These diverse objects include compact galaxies, apparently interacting pairs, galaxies with superluminous starforming regions and diffuse low surface brightness galaxies of various forms. The ‘irregulars’ and ‘peculiar’ galaxies contribute most of the excess counts in the I-band at our limiting magnitude, and may explain the ‘faint blue galaxy’ problem.
During 1990 we surveyed the southern sky using a multi-beam receiver at frequencies of 4850 and 843 MHz. The half-power beamwidths were 4 and 25 arcmin respectively. The finished surveys cover the declination range between +10 and −90 degrees declination, essentially complete in right ascension, an area of 7.30 steradians. Preliminary analysis of the 4850 MHz data indicates that we will achieve a five sigma flux density limit of about 30 mJy. We estimate that we will find between 80 000 and 90 000 new sources above this limit. This is a revised version of the paper presented at the Regional Meeting by the first four authors; the surveys now have been completed.
Early nutrition is critical for later health and sustainable development. We determined potential effectiveness of the Kenyan Community Health Strategy in promoting exclusive breastfeeding (EBF) in urban poor settings in Nairobi, Kenya. We used a quasi-experimental study design, based on three studies [Pre-intervention (2007–2011; n=5824), Intervention (2012–2015; n=1110) and Comparison (2012–2014; n=487)], which followed mother–child pairs longitudinally to establish EBF rates from 0 to 6 months. The Maternal, Infant and Young Child Nutrition (MIYCN) study was a cluster randomized trial; the control arm (MIYCN-Control) received standard care involving community health workers (CHWs) visits for counselling on antenatal and postnatal care. The intervention arm (MIYCN-Intervention) received standard care and regular MIYCN counselling by trained CHWs. Both groups received MIYCN information materials. We tested differences in EBF rates from 0 to 6 months among four study groups (Pre-intervention, MIYCN-Intervention, MIYCN-Control and Comparison) using a χ2 test and logistic regression. At 6 months, the prevalence of EBF was 2% in the Pre-intervention group compared with 55% in the MIYCN-Intervention group, 55% in the MIYCN-Control group and 3% in the Comparison group (P<0.05). After adjusting for baseline characteristics, the odds ratio for EBF from birth to 6 months was 66.9 (95% CI 45.4–96.4), 84.3 (95% CI 40.7–174.6) and 3.9 (95% CI 1.8–8.4) for the MIYCN-Intervention, MIYCN-Control and Comparison group, respectively, compared with the Pre-intervention group. There is potential effectiveness of the Kenya national Community Health Strategy in promoting EBF in urban poor settings where health care access is limited.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79° at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s−1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.
Though our knowledge of the circulation in this complex region is still incomplete, recent direct current measurements have identified four separate elements of the circulation which appear to undergo a seasonal variation of some sort. These are: (i) a summer-autumn maximum in the deep overflow of Norwegian Sea Deep Water across the Wyville-Thomson Ridge; (ii) an autumn minimum in the upper-ocean circulation around Rockall Bank, ascribed to Taylor Column processes; (iii) an autumn-winter maximum in the strength and breadth of the slope current along the European continental margin; (iv) a winter-spring maximum in eddy kinetic energy in the open waters of the Rockall Channel, and over the full depth range, as a function of windstress and stratification. The first three of these elements are of localised occurrence along the northern, western and eastern margins of the Channel and are described only briefly. The fourth process, encountered at a range of sites in the northeast Atlantic, is described in detail using a total data set of 68 instrument-years of direct current measurements recovered from the Rockall Channel in 1977–84. In the seasonally-varying 3–27 day (d) band of periods, eddy kinetic energies (kE) are shown to be depth-dependent in amplitude, but with little evidence of any significant phase-lag with either depth or location between the individual timeseries of kE estimates. These time-series demonstrate clearly and for the first time that the winterspring peaks in eddy kinetic energy lag the winter peaks in windstress by between 1 and 3 months. This phase-lag is explained as the cumulative result of wind forcing and eddy dissipation.
We have built and tested electrically small (∼γ/10) resonant patch antennas as proposed in recent literature [1, 2]. The metamaterial array loading the antennas formed a rough cylinder axially enclosed by a patch antenna and a ground plane. The fill ratio, or ratio of the metamaterial array's radius to the patch radius, was less than one. Given a particular negative permeability metamaterial (copper spiral rings printed on circuit board in this case), the fill ratio dictates the lower of two resonant frequencies of the antenna. The higher frequency resonance is characteristic of the patch.
We observed that each of the antennas radiated at two resonant frequencies, as predicted. The lower frequency resonance disappeared when the metamaterial was removed. We built two versions of this antenna, one (Design I) with a lower resonant frequency of 756 MHz and higher resonant frequency of 3.3 GHz, and a second antenna (Design II) with a lower resonant frequency of 385 MHz and higher resonant frequency of 1.8 GHz. Because we were interested in reducing the size of patch antennas, we focused on the lower frequency resonances in this work. The antennas' return loss was measured at -23 dB and -28 dB, the gains were -11 dBi and -13 dBi, and the return loss was less than -10 dB over bandwidths of 4.7% and 1.8% for the lower frequency resonances of Design I and Design II, respectively.
We also predicted the trend of increasing resonant frequency with decreased metamaterial fill ratio. We varied the fill ratio was by changing the patch size while maintaining the same metamaterial array. As predicted, resonant frequency increased with increasing patch size, an opposite trend to what one would expect without the loading metamaterial. Altering the patch size allows simple tuning during the assembly and test process.
Organopolysilane materials have recently demonstrated potential technological importance as positive photoresists, photoconductors, and nonlinear optical materials. Many of the technological applications of these materials depend intimately on the photoexcitation process in these materials, possibly resulting in either bond scission or the creation of mobile charge carriers. Herein we present some preliminary results of a model simulation of the photoexcitation process in oligomeric polysilane chains using a recently developed first-principles local-density functional method for the calculation of electronic structures,total energies, and gradients of the total energy with respect to nuclear coordinates.
The irradiation behavior of high-density uranium silicides has been a matter of interest to the nuclear industry for use in high power or low enrichment applications. Transmission electron microscopy studies have found that heavy ion bombardment renders U3Si and U3Si2 amorphous at temperatures below about 250 C , and that U3Si becomes mechanically unstable suffering rapid growth by plastic flow [2,3]. In this present work, crystallographic changes preceding amorphization by fission fragment damage have been studied by high-resolution neutron diffraction as a function of damage produced by uranium fission at room temperature. Initially, both silicides had tetragonal crystal structures. Crystallographic and amorphous phases were studied simultaneously by combining conventional Rietveld refinement of the crystallographic phases with Fourier filtering analysis of the non-crystalline scattering component .
Grain boundary chemical diffusivities for a series of symmetric  tilt boundaries in the Au/Ag system were measured by the surface accumulation method using newly developed thin-film multi-crystal specimens, in which the grain boundaries feeding the accumulation surface were all of the same type. Possible effects due to segregation at the grain boundaries and surfaces were avoided. CSL boundaries of low-Σ ( i.e., 5, 13, 17, 25) and also more general boundaries with tilt angles between the low-Σ orientations were selected. The diffusivities were found to vary monotonically with tilt angle ( i.e., no cusps at low-Σ's were found) in a manner consistent with the Structural Unit model.