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Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy data demonstrating that sulfur is accommodated predominantly in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mechanism. Minor sulfide and sulfite peaks in the X-ray photoelectron spectra, however, also indicate that more complex substitution mechanisms incorporating S2– and S4+ are possible. Incorporation of S6+ through clino-anhydrite-type substitution results in an excess of M2+ cations, which previous workers have suggested is accommodated by auxiliary substitution of OH– for O2–. However, Raman data show no indication of OH–, and instead we suggest charge imbalance is accommodated through F– substituting for O2–. The accommodation of S in the monazite-(Ce) results in considerable structural distortion that may account for relatively high contents of ions with radii beyond those normally found in monazite-(Ce), such as the heavy rare earth elements, Mo, Zr and V. In contrast to S-bearing monazite-(Ce) in other carbonatites, S-bearing monazite-(Ce) at Eureka formed via a dissolution–precipitation mechanism during prolonged weathering, with S derived from an aeolian source. While large S-bearing monazite-(Ce) grains are likely to be rare in the geological record, formation of secondary S-bearing monazite-(Ce) in these conditions may be a feasible mineral for dating palaeo-weathering horizons.
Starting in 2016, we initiated a pilot tele-antibiotic stewardship program at 2 rural Veterans Affairs medical centers (VAMCs). Antibiotic days of therapy decreased significantly (P < .05) in the acute and long-term care units at both intervention sites, suggesting that tele-stewardship can effectively support antibiotic stewardship practices in rural VAMCs.
We have developed high affinity Molecularly Imprinted Polymers (MIPs) for neurotransmitters such as dopamine, noradrenaline and caffeine. These polymer particles are mixed within the bulk of screen-printed ink allowing masss-producible bulk modified MIP Screen-Printed Electrodes (MIP-SPEs) to be realised. We have explored different SPE supporting surfaces, such as polyester, tracing paper and household-printing paper. The performance of those MIP-SPEs is studied using the Heat-Transfer Method (HTM), a patented thermal method. With the combination of screen-printing techniques and thermal detection, it is possible to develop a portable sensor platform that is capable of low-cost and straightforward detection of biomolecules on-site. In the future, this unique sensor architecture holds great promise for the use in biomedical devices.
We analysed data from a prospective cohort of 255024 adults aged ⩾45 years recruited from 2006–2009 to identify characteristics associated with a zoster diagnosis. Diagnoses were identified by linkage to pharmaceutical treatment and hospitalization records specific for zoster and hazard ratios were estimated. Over 940583 person-years, 7771 participants had a zoster diagnosis; 253 (3·3%) were hospitalized. After adjusting for age and other factors, characteristics associated with zoster diagnoses included: having a recent immunosuppressive condition [adjusted hazard ratio (aHR) 1·58, 95% confidence interval (CI) 1·32–1·88], female sex (aHR 1·36, 95% CI 1·30–1·43), recent cancer diagnosis (aHR 1·35, 95% CI 1·24–1·46), and severe physical limitation vs. none (aHR 1·33, 95% CI 1·23–1·43). The relative risk of hospitalization for zoster was higher for those with an immunosuppressive condition (aHR 3·78, 95% CI 2·18–6·55), those with cancer (aHR 1·78, 95% CI 1·24–2·56) or with severe physical limitations (aHR 2·50, 95% CI 1·56–4·01). The novel finding of an increased risk of zoster diagnoses and hospitalizations in those with physical limitations should prompt evaluation of the use of zoster vaccine in this population.
We report on a preliminary analysis of a 5600 sec per point survey of 32 square degrees in Centaurus, carried out with the Parkes 13-beam system. The signal-to-noise ratio is found to improve as for the whole integration. We have detected 102 HI sources between +250 and +12,700 km s−1 either by eye or by using the new galaxy-finding algorithm PICASSO. Over half of these are new HI detections. Around a dozen of these are not associated with catalogued galaxies and, in two of these cases, we have not identified an optical counterpart on the Digitized Sky Survey. Arguments are put forward to explain why deep integrations are needed to find low surface brightness objects.
Limitations of access have long restricted exploration and investigation of the cavities beneath ice shelves to a small number of drillholes. Studies of sea-ice underwater morphology are limited largely to scientific utilization of submarines. Remotely operated vehicles, tethered to a mother ship by umbilical cable, have been deployed to investigate tidewater-glacier and ice-shelf margins, but their range is often restricted. The development of free-flying autonomous underwater vehicles (AUVs) with ranges of tens to hundreds of kilometres enables extensive missions to take place beneath sea ice and floating ice shelves. Autosub2 is a 3600 kg, 6.7 m long AUV, with a 1600 m operating depth and range of 400 km, based on the earlier Autosub1 which had a 500 m depth limit. A single direct-drive d.c. motor and five-bladed propeller produce speeds of 1–2 m s−1. Rear-mounted rudder and stern-plane control yaw, pitch and depth. The vehicle has three sections. The front and rear sections are free-flooding, built around aluminium extrusion space-frames covered with glass-fibre reinforced plastic panels. The central section has a set of carbon-fibre reinforced plastic pressure vessels. Four tubes contain batteries powering the vehicle. The other three house vehicle-control systems and sensors. The rear section houses subsystems for navigation, control actuation and propulsion and scientific sensors (e.g. digital camera, upward-looking 300 kHz acoustic Doppler current profiler, 200 kHz multibeam receiver). The front section contains forward-looking collision sensor, emergency abort, the homing systems, Argos satellite data and location transmitters and flashing lights for relocation as well as science sensors (e.g. twin conductivity–temperature–depth instruments, multibeam transmitter, sub-bottom profiler, AquaLab water sampler). Payload restrictions mean that a subset of scientific instruments is actually in place on any given dive. The scientific instruments carried on Autosub are described and examples of observational data collected from each sensor in Arctic or Antarctic waters are given (e.g. of roughness at the underside of floating ice shelves and sea ice).
GaInNAsSb quantum wells with GaNAs barriers, grown via molecular beam epitaxy (MBE) on 100–oriented GaAs substrates at varying temperatures, were analyzed using photoluminescence (PL), high-resolution x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive spectrometry (EDS). Samples grown at 420 °C, 440 °C, and 470 °C were analyzed, as were two pieces of the 440 °C growth temperature sample that had been annealed at 740 °C and 820 °C. These measurements showed that the decrease in PL with higher growth temperatures was due to the onset of 3D growth and the nucleation of dislocations. The degradation associated with overannealing was likely due to dislocation nucleation. The poor PL associated with low growth temperatures was due to another mechanism, most likely arsenic anti-site defects. EDS measurements showed greater composition uniformity with lower growth temperatures, as expected, and also showed that there was no ordered indium-rich or indium-poor phase separation at any temperature. Phase separation upon annealing was not observed.
The dilute-nitride GaInNAs shows great promise in becoming the next choice for 1 eV photodetector and multi-junction photovoltaic applications due to the ability for it to be grown lattice-matched on GaAs substrates. This paper will present results from high-power photodetector devices fabricated from high-quality thick GaInNAs and metamorphic InGaAs materials grown by MBE. The internal quantum efficiency of rear-illuminated PIN photodiodes with thick GaInNAs films as the intrinsic region (roughly 62% at 1064 nm) is somewhat lower than comparable metamorphic InGaAs devices (roughly 75% at 1064 nm). However, the dark current density of the GaInNAs devices is also somewhat lower (roughly 3 μA/cm2 at 2×104 V/cm bias) than the InGaAs devices (roughly 20 μA/cm2 at 2×104 V/cm bias), while the breakdown voltages (beyond -20 V) are comparable. Materials characterization of each structure, including x-ray diffraction and room-temperature as well as temperature-dependent photoluminescence studies will be presented in order to explain the characteristics observed in the devices composed of the two different material systems.
Heterojunction band offsets of GaNAsSb/GaAs, GaInNAsSb/GaAs, and GaInNAsSb/GaNAs/GaAs quantum well (QW) structures were measured by photoreflectance (PR) spectroscopy. These samples were grown by solid-source molecular beam epitaxy using a radio-frequency nitrogen plasma source. PR spectra were collected from the QW structures and the energy transitions were obtained. The experimental data of the QW energy transitions were analyzed by theoretical calculations. Using predetermined values such as QW thickness and composition, unknown factors such as the heterojunction band offsets were able to be determined. For the GaN0.02As0.87Sb0.11/GaAs structure, we found that Qc≈0.5. For Ga0.62In0.38N0.026As0.954Sb0.02/GaAs, we found that Qc≈0.8. This value is similar to the antimony free dilute-nitride material GaInNAs since the small amount of antimony does not affect the band offsets. For the technologically important Ga0.61In0.39N0.023As0.957Sb0.02/GaN0.027As0.973/GaAs laser structure, we found that the GaInNAsSb/GaNAs QW had a conduction band offset of 144 meV and a valence band offset of 127 meV. With a greater understanding of the band structure, more advanced GaInNAsSb laser devices can be obtained.
The need to reduce costs while providing a first-class service has led to the expansion in the role of nurses in recent years. We present results of a comparison of the cost-effectiveness of conventional and nurse-led out-patient ear clinics. Our results indicate that cost-effective health care is a distinct competitive advantage for nurses taking up some roles conventionally performed by doctors. The difference in mean cost of out-patient visit per patient between the two groups is £75.28. This is equivalent to a reduction in cost to the hospital of more than £47000 for the 626 patients seen in a nurse-led ear clinic in a year. The nurse-led service is thus more cost-effective and presents an opportunity by freeing up otolaryngologists’ time to see more complex patients and has the potential for reducing out-patient access time in the NHS.
In November 1973 Newcastle disease suddenly appeared in Northern Ireland, where the viscerotropic disease had not been seen in 3½ years and the two Irelands had been regarded as largely disease free for 30 years. It was successfully controlled with only 36 confirmed affected layer flocks, plus 10 more slaughtered as ‘dangerous contacts’. Contemporary investigations failed to reveal the source of the Irish epidemic. Using archival virus samples from most of the affected flocks, RT–PCR was conducted with primers selected for all six NDV genes. Phylogenetic analyses of three genes, HN, M and F, confirmed vaccine as the cause of one of the outbreaks. The other six samples were identical and closely related to previous outbreaks in the United States and western Europe initiated by infected imported Latin American parrots. The probable cause of the epidemic followed from the importation from The Netherlands of bulk feed grains contaminated with infected pigeon faeces.
Atomic oxygen treatment has been investigated as an unconventional option for art restoration where conventional methods have not been effective. Exposure of surfaces to atomic oxygen was first performed to investigate the durability of materials in the low Earth orbit environment of space. The use of the ground based environmental simulation chambers, developed for atomic oxygen exposure testing, has been investigated in collaboration with conservators at a variety of institutions, as a method to clean the surfaces of works of art. The atomic oxygen treatment technique has been evaluated as a method to remove soot and char from the surface of oil paint (both varnished and unvarnished), watercolors, acrylic paint, and fabric as well as the removal of graffiti and other marks from surfaces which are too porous to lend themselves to conventional solvent removal techniques. This paper will discuss the treatment of these surfaces giving an example of each and a discussion of the treatment results.
Deaf children of elementary and secondary school age participated in a study designed to
examine their understanding of display rules, the principles governing the expression and
concealment of emotion in social situations. The results showed that deaf children's
knowledge of display rules, as measured by their reported concealment of emotion, was
comparable to that of hearing children of the same age. However, deaf children were less
likely to report that they would conceal happiness and anger. They were also less likely to
produce reasons for concealing emotion and a smaller proportion of their reasons were
prosocial, that is, relating to the feelings of others. The results suggest that the understanding
of display rules (which function to protect the feelings of other people) may develop more
gradually in deaf children raised in a spoken language environment than it does in hearing
After PCR amplification with conservative cytomegalovirus primers, a 520 nucleotide putative
partial sequence of the DNA polymerase gene of porcine cytomegalovirus (PCMV) was
determined. Sequence comparison revealed homology to DNA polymerase genes from various
beta herpes viruses and a dendrogram was constructed depicting the relationship of PCMV to
other members of the Herpesviridae family. The dendrogram indicates that PCMV is indeed a
beta herpes virus that is more closely related to human herpes virus types 6 and 7 than to
To address the difficulties encountered during conventional PCMV detection and
characterization a set of nested PCR primers were constructed which generated DNA
fragments of 415 and 257 bp from the DNA polymerase gene. The nested PCR system proved
specific for PCMV and provided a novel means for the detection of this poorly characterized
herpes virus in pig populations, vaccines and in organs used in xenotransplantation.
Very fine-grained Ni and Cu films were formed using pulsed laser deposition onto fused silica substrates. The grain sizes in the films were characterized by electron microscopy, and the mechanical properties were determined by ultra-low load indentation, with finite-element modeling used to evaluate the properties of the layers separately from those of the substrate. Some Ni films were also examined after annealing to 350 and 450°C to enlarge the grain sizes. These preliminary results show that the observed hardnesses are consistent with a simple extension of the Hall-Petch relationship to grain sizes as small as 11 nm for Ni and 32 nm for Cu.
Over the last ten years, the application of high frequency dielectric spectroscopy techniques for the assessment of composite structures has been investigated. Novel approaches to assess non-destructively the evolution during ageing of adhesively bonded carbon fibre reinforced plastic (CFRP) structures and bulk glass fibre reinforced plastic (GRP) structures are presented in this paper and the results are critically assessed.
The applicability and limitations of dielectric measurements, in both frequency and time domain, to the monitoring of water ingress at 30°C and 60°C are examined. The correlation between gravimetric and high frequency dielectric spectroscopy data demonstrates the suitability of the techniques regarding the assessment of water uptake in composites structures and illustrates its potential as a non-destructive evaluation (NDE) technique. The dielectric time domain response (TDR) study of adhesively bonded structures indicates a new way to assess such structures. The approach for frequency domain analysis of bulk GRP using a coaxial probe technique indicates the potential portability of the technique for in-situ measurements.
Deaf children aged 4 to 16 years were given a false-belief test
of theory of mind. Although
the children experienced difficulty with the test, relative to hearing
children, confirming a
report by Peterson and Siegal (1995), performance was age-related, with
higher proportion of 13- to 16-year-olds passing the test. It was concluded
that deaf children
raised in a spoken language environment show a developmental delay in theory
acquisition. This delay is consistent with the assumption that their early
learning about mental states are relatively restricted and that the normal
theory of mind is dependent upon such opportunities.