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Introduction: Bronchiolitis is a viral respiratory infection and the most common reason for hospitalization of infants. Despite evidence that few interventions are beneficial in patients with bronchiolitis, other studies would have shown that a significant proportion of patients undergo various forms of low value care. This objective of this project was to 1. establish baseline management of bronchiolitis in the Calgary Zone, and 2. deliver audit and feedback (A&F) reports to pediatric emergency physicians (PEP) to identify opportunities and strategies for practice improvement. Methods: This retrospective cohort study included all patients 12 months old that presented to a Calgary emergency department or urgent care center with a diagnosis of bronchiolitis from April 1, 2013 to March 31, 2017. Using data from various electronic health data sources, we captured age, vital signs, CTAS, common therapeutic interventions (bronchodilators, steroids, antibiotics) and investigations (chest x-ray (CXR), viral studies, antibiotics). Results were stratified by site and by admission status. Descriptive statistics were used to report baseline characteristics and interventions. Interhospital ranges (IHR) were provided to compare different hospitals in the zone. For the A&F component of the project, consenting PEP received a report of both their individual and peer comparator data and an in-person multi-disciplinary facilitated feedback session. Results: We included 4023 patients from all 6 sites (range from 28 to 3316 patients). Admission rates were 21.7% (IHR 0-29%). Mean age was 5.4 months old. Bronchodilator use was 27.0% (IHR 21-41%). 22.0% of patients received a CXR (IHR 0-57%) and 30.3% had viral studies done (IHR range 0.8-33%). PEP had higher usage of viral studies (30% vs 5.7%), whereas non-PEP had higher CXR usage (46.2% vs 23.4%). 41 of 66 PEP consented to receive their individual A&F reports (62%). In the facilitated feedback session PEP 1. identified two areas (bronchodilators and viral studies) where improvements could be made and 2. discussed specific strategies to decrease practice variation and minimize low value care including development of a multi-disciplinary care pathway, alignment with in-patient management, education and repeated A&F reports. Conclusion: Significant variability exists in management of patients with bronchiolitis across different hospitals in our zone. A facilitated feedback session identified areas for improvement and multi-disciplinary strategies to reduced low value care for patients with bronchiolitis. Future phases of this project include repeated data in 6 months and implementation of a provincial care pathway for the management of bronchiolitis.
Late-summer subglacial water pressures have been measured in a dense array of boreholes in the ablation area of Haut Glacier d’Arolla, Switzerland. Interpolated surfaces of minimum diurnal water pressure and diurnal water-pressure variation suggest the presence of a subglacial channel within a more widespread, distributed drainage system. The channel flows along the centre of a variable pressure axis (VPA), some tens of metres wide, that is characterized by low minimum diurnal water pressures (frequently atmospheric) and high diurnal water-pressure variations. These characteristics are transitional over a lateral distance of c. 70 m to higher and more stable subglacial water pressures in the adjacent distributed system. Water-pressure variations recorded in boreholes located close to the centre of the VPA reflect the delivery of surface-derived meltwater to the glacier bed and result in a diurnally reversing, transverse hydraulic gradient that drives water out from the channel into the distributed system during the afternoon and back to the channel overnight. Subglacial observations suggest that such flow occurs through a vertically confined sediment layer. Borehole turbidity records indicate that the resulting diurnal water flows are responsible for the mobilization and transport of fine debris in suspension. Analysis of the propagation velocity and amplitude attenuation cf the diurnal pressure waves suggests that the hydraulic conductivity of the sediment layer decreases exponentially with distance from the channel, falling from c. 10−4 m s−1 at the channel boundary to c. 10−7 m s−1 70 m away. These apparent hydraulic conductivities are consistent with Darcian flow through clean sand and typical glacial till, respectively.
We suggest that fine material is systematically flushed from basal sediments located adjacent to large, melt-season drainage channels beneath warm-based glaciers. This process may have important implications for patterns of glacier erosion, hydro-chemistry and dynamics.
The paper is an investigation into the withdrawal rates of seven Scottish Offices and covers the years 1972-76 with an appendix giving the results for 1977.
The rates were basically analysed by class and duration with further investigations mainly on the 1976 data by age at entry, sex, size of sum assured, premium paying term, premium payment frequency and by type of agent introducing the business. Comparisons were made of the level of withdrawal rates among the various Offices and also the variations from year to year separately. A graduation of the combined data for 1975 and 1976 for each of the five main classes was carried out.
Fire is often used in northern grasslands to control invasive grass species but has unknown effects on Tamarix spp., more recent invaders. Temperature (using an oven as a fire surrogate) and duration combinations that would be most lethal to Tamarix seeds and seedlings were determined. Tamarix seeds were sown in soil-lined dishes, water added to saturation, and seedlings grown for 1 to 5 d. Seeds were also placed in water-saturated or dry soil just before temperature exposure (79 to 204 C [175 to 400 F]) by duration (1 to 5 min) treatments. After treatment, soil water loss was measured by weight difference, and surviving seedlings were counted for 6 d. Tamarix seedling establishment and survival decreased with increasing temperature and duration. The 5-d-old seedlings were the most affected. No 5-d-old seedlings survived 1- and 2-min exposures to 204 C, whereas 1-d-old seedlings had greater than 25% survival. If soils were saturated, two to four times more seedlings established following seed exposure to 177 and 204 C. Longer durations at lower temperatures were required to reduce Tamarix survival. Increasing duration from 2 to 5 min at 121 C decreased 5-d-old seedling survival from more than 80% to less than 10% and eliminated those seedlings at 149 C. Five minutes at 149 C decreased dry-soil seed viability to about 15%, whereas germination on saturated soils remained high (∼75%). No seeds survived the exposure to 177 and 204 C. Soil moisture loss values associated with 90% mortality of 5- and 1-d-old seedlings were 1.7 and 2.2%, respectively. On saturated soils, 90% of seeds died with 2.5% water loss. Under suitable conditions, fire can decrease Tamarix seedling survival. Fire may be useful for controlling Tamarix seedlings in northern grasslands and should be considered for management of new invasions.
Controlled burns and grazing are being tested to manage invasive grasses in the Prairie Pothole region of the Northern Great Plains. These practices, however, may inadvertently promote saltcedar infestations from seed by opening the vegetative canopy. Saltcedar seedling establishment was investigated in greenhouse experiments using intact soil cores from one summit and three footslope sites in eastern South Dakota. Establishment tests were conducted in soil cores collected from treatment and control plots immediately after spring fire treatment (postburn) and in cores that contained peak cool- or peak warm-season vegetation, with or without clipping (simulated grazing treatment), to simulate vegetation conditions typical of saltcedar seed-shed in northern regions. Cores were seeded with 100 saltcedar seeds and subirrigated to maintain high soil water conditions, characteristic of the environment near potholes during late spring/early summer. Seedlings were counted during the first 3 wk to estimate establishment and the height of five seedlings core−1 were measured weekly to estimate growth rates. Opening the canopy with fire or clipping increased saltcedar establishment. Cores taken immediately after fire treatment had two times more seedlings establish (38% vs. 19%) and greater average seedling growth rate (1.5 mm d−1 vs. 0.9 mm d−1) when compared with no-fire controls. Fire after seeding reduced seedling establishment to 5%, but did not affect growth rate. Saltcedar establishment in peak cool-season vegetation cores was 6% regardless of earlier fire treatment, whereas in peak warm-season vegetation, establishment ranged from 8% (no spring fire) to 17% (spring fire). If soils remain wet, invasion risk following spring fire may be greatest when warm-season grasses are flowering because this time coincides with northern saltcedar seed production. Areas adjacent to viable saltcedar seed sources should be managed to maximize canopy cover when seeds are released to limit further establishment. Fire after saltcedar seed deposition may control propagules and young seedlings.
In Sweden, it is proposed that spent fuel should be encapsulated in sealed cylindrical canisters for disposal in a geologic repository. The canisters would consist of a thick ferrous inner container and a copper overpack. If mechanical failure of the copper overpack occurred, allowing water to enter, the ferrous inner container would corrode anaerobically and liberate hydrogen. The rate of hydrogen generation due to the anaerobic corrosion of steel in anoxic groundwater has been measured using barometric cells. The aim of the work presented in this paper was to measure the redox potential, Eh and pH in the presence of anaerobically corroding steel, in a barometric cell. Two specially designed barometric cells were constructed. They were equipped with a silver chloride or calomel reference electrode, a gold Eh electrode, a glass electrode, and a steel electrode. The electrodes were allowed to stabilize in anoxic artificial groundwater and then a mass of pickled steel wire was introduced into the test cell. As the wires were added, the redox potential rapidly became more negative due to the rapid consumption of the residual oxygen. The corrosion potential of the steel was stable and a slow drift in pH was observed. The results are compared with the results of geochemical modelling. Extension of the work to investigate the electrochemical parameters in the presence of dissolved uranium species is discussed.
In this study, the multicomponent electrode approach was used in an attempt to simultaneously improve the cell's specific energy values by shifting the cathode's voltage up to the 5V-region, combined with the increased specific capacity via addition of the second electrode component. The electrode materials were prepared by variety of synthetic methods (e.g. solid state, sol-gel, mechanical mixing etc.) and tested for lithium-ion intercalation properties. Structural properties and morphology of synthesized materials were characterized by X-ray diffraction (XRD) methods. The prospective 5V cathode materials were investigated as cathodes in the cells with lithium-metal counter electrode.
The perovskite CaTiO3 is one of the major phases of the Synroc titanate mineral assemblage. Its chemical durability in an aqueous environment, which is relevant to the Synroc concept, has been investigated by solution analysis, surface analysis and electron microscopy. In general it has been found that dissolution due to base catalyzed hydrolysis is the most significant mechanism of attack; the results suggest that an ion exchange mechanism is confined to the first monolayer. Below 90°C the extent of attack, and release of Ca into solution, is limited by the formation of a titanaceous amorphous layer (” 100A thickness) which imposes a reaction constraint at the film-solid interface. Dissolution may also be constrained by the pH and Ca2+concentration in the bulk liquid. Above 90°C dissolution is relatively less constrained due to instability of the amorphous layer which is replaced by nucleation and epitaxial growth of TiO2 on the dissolving substrate. Thermodynamic stability of CaTiO3 for T< 90°C can easily be engineered into the waste repository, while hydrothermal stability (T > 90°C) is more difficult to achieve.
Chemical vapor deposition of metals is becoming a desirable alternative to physical deposition techniques (e.g. sputtering, evaporation) for applications in chip wiring. This is due to the possibility of achieving highly conformal coverage and low processing temperatures. Additionally, it is convenient to be able to enhance the physical properties (e.g. corrosion resistance, adhesion, electromigration resistance) of metal films used for chip interconnection by incorporation of an alloying agent. We have investigated the possibility of extending our current copper deposition process to allow for the deposition of copper alloys. By careful selection of the precursors and reactor conditions, simultaneous decomposition of the two compounds to give clean alloy films is effected. Using this co-deposition method, Cu-Co and Cu-Te alloy films were prepared. Precursor and reaction chemistry are discussed as well as some properties of the resulting films.
Several conductive structures, which appeared to be usable as base electrodes for integrated devices based on high dielectric materials, have been annealed for 30 minutes in oxygen at 650 °C. Similar structures coated with lead-based ferroelectrics deposited by the sol-gel method have been annealed for 1 min in oxygen at higher temperatures. The materials have been characterized by Rutherford backscattering (RBS) and scanning electron microscopy (SEM) and the crystallographic structure of the ferroelectrics films has been determined by X-ray diffractometry (XRD).
Only RuO2/Ru has been found to be suitable as an electrode, at temperatures not exceeding 650 °C. It has also been found that the electrode materials can strongly affect the crystallization behavior of the sol-gel ferroelectric films and the formation of single-phase perovskite layers.
Bulk GaAsP, 20Å–500Å GaAsP/GaInP single quantum wells and 70 Å period GaAsP/GaInP superlattices were deposited on GaAs substrates by Flow Modulation Epitaxy. In these structures, the disordered GaInP is lattice matched while the GaAsP is in tension with the As mole fraction varying from 0.6 to 1. The structures were studied using asymmetric x-ray diffraction, 1K photoluminescence, Raman scattering, transmission electron microscopy and atomic force microscopy. Raman and x-ray diffraction are used to assess the structural quality of the superlattices, especially with regard to the presence/absence of superlattice x-ray satellites and disorder activated longitudinal acoustic phonons. A model including the effects of composition, strain, and confinement on longitudinal optic phonons is described and used to estimate the composition, using Raman scattering, in the thin, pseudomorphic GaAsP layers in the superlattices. Photoluminescence is used to assess the composition of the interfacial layers in the single quantum wells and to determine transition energies in the superlattices. In addition, analysis of the heterostructure luminescence, including prediction of the energy band alignment as calculated with the model solid theory corrected for strain, is found to suggest the presence of a type II band alignment in the heterostructures for some values of GaAsP composition. Finally, Raman scattering and x-ray diffraction are used to compare arsenide to phosphide interfaces in GaAs and InP-based heterostructures.
We have investigated cyclopentadienyl (Cp) complexes of Ru and Os as precursors for low temperature CVD of pure ruthenium and osmium films. Films were grown on a variety of substrates in a warm-walled CVD reactor, equipped with a resistively heated wafer chuck, massflow controllers for carrier gas regulation, and a mechanically-backed oil-vapor diffusion pump. Typical depositions were done under ca. 1 Torr total pressure. Use of air or oxygen as a carrier gas and Cp2M (M = Ru or Os) as precursors gave high purity, conformal films of ruthenium and osmium at temperatures as low as 275°C and 350°C, respectively. Under these conditions, the only observable by-products were CO2 and H2O, indicating that surface-catalyzed, complete oxidation of the ligands was involved in the decomposition process. Growth rates, film purities, resistivities and conformality were measured.
Bulk GaAsP, 20Å-500Å GaAsP/GaInP single quantum wells and 70 Å period GaAsP/GaInP superlattices were deposited on GaAs substrates by Flow Modulation Epitaxy. In these structures, the disordered GaInP is lattice matched while the GaAsP is in tension with the As mole fraction varying from 0.6 to 1. The structures were studied using asymmetric x-ray diffraction, 1K photoluminescence, Raman scattering, transmission electron microscopy and atomic force microscopy. Raman and x-ray diffraction are used to assess the structural quality of the superlattices, especially with regard to the presence/absence of superlattice x-ray satellites and disorder activated longitudinal acoustic phonons. A model including the effects of composition, strain, and confinement on longitudinal optic phonons is described and used to estimate the composition, using Raman scattering, in the thin, pseudomorphic GaAsP layers in the superlattices. Photoluminescence is used to assess the composition of the interfacial layers in the single quantum wells and to determine transition energies in the superlattices. In addition, analysis of the heterostructure luminescence, including prediction of the energy band alignment as calculated with the model solid theory corrected for strain, is found to suggest the presence of a type II band alignment in the heterostructures for some values of GaAsP composition. Finally, Raman scattering and x-ray diffraction are used to compare arsenide to phosphide interfaces in GaAs and InP-based heterostructures.
The state of the art (SOA) Li-ion cells utilize carbon anodes. However, to improve specific energy, energy density, and safety of cells using carbon anodes, alternative anodes must be developed. Recently, Fuji Film Inc. has suggested the use of tin oxide based anodes in Li-ion cells. It is believed mat cells containing tin oxide based anodes have the potential to meet the need for NASA's future missions. As a result, we conducted an analysis to compare the performance of cells containing carbon anodes and cells containing tin oxide anodes. The comparison between these cells involved the following: 1) reaction mechanisms between Li and carbon and reaction mechanisms between Li and tin oxide, 2) half-cell and full-cell performance characteristics, 3) interactions between the anode materials and electrolyte types and compositions, and 4) the optimization of binder composition.
Ultraviolet light-emitting diodes (UV LEDs) with AlxGa1−xN/AlyGa1−yN multiple quantum well (MQW) active regions, doped in the barriers with different Si doping level, show a sharp near band-edge emission (UV luminescence). Besides the near band-edge emission, some samples also show parasitic emissions with a broad peak centered at about 520 nm (green luminescence). The EL intensities of the UV emission line and the green emission line are studied. The UV luminescence peak intensity increases superlinearly with the injection current, following a power law with an exponent of about 2.0. In contrast, the green luminescence peak intensity increases linearly with the injection current, with an exponent of about 1.0. A theoretical model is proposed to explain the relationship between the peak intensities and the injection current. The results obtained from the model are in excellent agreement with the experimental results. The model provides a method to evaluate the dominant recombination process by measuring the exponent of the power-law dependence.
In this paper, the authors examine a number of ways of implementing characteristic three arithmetic for use in cryptosystems based on the Tate pairing. Three alternative representations of the field elements are examined, and the resulting algorithms for the field addition, multiplication and cubing are compared. Issues related to the arithmetic of supersingular elliptic curves over fields of characteristic three are also examined. Details of how to compute the Tate pairing itself are not covered, since these are well documented elsewhere.
Visual markers detectable by histochemical staining have been developed
for analysing the time course and tissue specificity of maize
infections by Fusarium moniliforme. Three F. moniliforme
strains, RRC 374, MRC 826 and RRC PAT, were transformed with a
plasmid, pHPG, containing the gusA reporter gene which codes for
β-glucuronidase (GUS) and the hph gene for hygromycin
resistance as the selectable marker. Introduction of plasmid DNA into germinating
conidia yielded 1·2×10−7
transformants per conidium; expression of both gusA and hph
was however, transient. Stable transformants were obtained using protoplasts
recipient, but transformation frequency was reduced. Southern blot and
PCR analyses confirmed incorporation of pHPG into the
genome of all three F. moniliforme strains with gusA
properly inserted in MRC 826 and RRC PAT, but apparently disrupted in RRC
374. The growth pattern for transformed F. moniliforme isolates
and the parental wild types followed a sigmoid curve on minimal
and enriched media. Hygromycin totally inhibited growth for wild type isolates,
but not of transformants. Transformed isolates
maintained the ability to infect the maize plant. Thus, this study is the
first report of F. moniliforme transformed with a visibly
detectable reporter gene to use for analysing this endophyte-host interaction
of world-wide importance to animal and human health.
The head-one interaction of a supersonic streamwise vortex with
a circular cylinder
reveals a vortex breakdown similar in many ways to that of incompressible
breakdown. In particular, the dramatic flow reorganization observed during
interaction resembles the conical vortex breakdown reported by Sarpkaya
high Reynolds number. In the present study, vortex breakdown is brought
moderate and strong streamwise vortices encounter the bow shock in front
of a circular
cylinder at Mach 2.49. The main features of the vortex/cylinder interaction
formation of a blunt-nosed conical shock with apex far upstream of the
shock stand-off distance, and a vortex core which responds to passage through
of the conical shock by expanding into a turbulent conical flow structure.
geometry of the expanding vortex core as well as the location of the conical
are seen to be strong functions of the incoming vortex strength and the
diameter. A salient feature of the supersonic vortex breakdown is the formation
entropy-shear layer, which separates an interior subsonic zone
containing the burst
vortex from the surrounding supersonic flow. In keeping with the well-established
characteristics of the low-speed vortex breakdown, a region of reversed
observed inside the turbulent subsonic zone. The steady vortex/cylinder
flow fields generated in the current study exhibit many characteristics
of the unsteady
vortex distortion patterns previously observed during normal shock wave/vortex
interactions. This similarity of the instantaneous flow structure indicates
phenomenon previously called vortex distortion
by Kalkhoran et al. (1996) is a form of
supersonic vortex breakdown.