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Studies estimating the human health impact of the foodborne disease often include estimates of the number of gastroenteritis hospitalisations. The aims of this study were to examine the degree to which hospital discharge data underreport hospitalisations due to bacterial gastroenteritis and to estimate the frequency of stool sample submission among patients presenting with gastroenteritis. Using linked laboratory and hospital discharge data from a healthcare organisation and its affiliated hospital, we examined the International Classification of Disease (ICD-9-CM) diagnosis codes assigned to hospitalised adults with culture-confirmed Campylobacter, Salmonella, or Escherichia coli O157 infections and determined the frequency of stool sample submission. Among 138 hospitalised patients with culture-confirmed infections, 43% of Campylobacter patients, 56% of Salmonella patients and 35% of E. coli O157 patients had that pathogen-specific code listed on the discharge record. Among patients without their infection listed as a diagnosis, 65% were assigned a nonspecific gastroenteritis code. Submitting a specimen for culture ⩾3 days before discharge was significantly associated with having the pathogen-specific diagnosis listed. Of 6181 patients assigned a nonspecific gastroenteritis code, 69% had submitted a stool sample for bacterial culture. This study can be used to understand differences and adjust for the underreporting and underdiagnosed of Campylobacter, Salmonella and E. coli O157 in hospital discharge and surveillance data, respectively.
A QTL (TM-QTL) identified on ovine chromosome 18 (Walling et al., 2004), which increases loin muscle depth by 4-8% in UK Texel sheep, is of interest for the sheep industry as a potential means to increase carcass value. Since the contribution of Texel genes to the UK slaughter generation is generally through use of Texel sires to produce crossbred slaughter lambs (e.g. Texel x Mule lambs), it is necessary to verify the effects of the TM-QTL on loin muscularity and other carcass traits in such crossbred progeny of Texel sires before explotiation of the TM-QTL in commercial sheep populations.
Livestock farming is a traditional and important contributor to the rural economy in the hills and uplands of the UK. However, significant areas of the uplands have seen a decline in the condition of heath and mire habitats and the loss of dwarf shrubs as a result of over-grazing. Attempts to halt the decline and improve the condition of upland heath and mire habitats have been undertaken by the introduction of agri-environment schemes. In the main, such schemes rely on the reduction of sheep numbers. However, recent Defra funded research (LS1508) has indicated that this can result in dominance by competitive and/or unpalatable species such as purple moor-grass (Molinia caerulea ) or mat-grass (Nardus stricta ), leading in time to a reduction in the physical and financial performance of the flock. The objective of this study is to assess the impact of cattle grazing on Nardus stricta dominated pasture on sheep and cattle performance. It is being carried out as part of a wider project to determine environmentally sustainable and economically viable grazing systems for heather moorland.
Sheep group breeding schemes have gained in popularity in recent years. The objectives of group breeding schemes are to improve desirable traits such as carcass conformation, weight and maternal ability whilst maintaining local type. However, if group breeding schemes were to work together then a larger genetic pool of performance recorded animals would be available to facilitate improvements. The objectives of this project were therefore twofold, 1.) was to improve traits such as weight and carcass conformation and 2.) to demonstrate the benefits of cooperative groups working together. In this project, group breeding schemes from North and Mid Wales have been working together with ram performance testing groups from North, South and Mid Wales to improve results from Welsh Mountain breeding schemes.
The James Webb Space Telescope (JWST) is scheduled for launch in 2018. To operate and observe efficiently, JWST will rely on various external astrometric and photometric catalogues, in particular the HST Guide Star Catalog (GSC), for instance to locate sources accurately on the sky. The incorporation of the Gaia astrometric catalog will improve the absolute astrometry of the GSC and is therefore relevant for JWST operations. We outline how the JWST Science and Operations Center hosted at the Space Telescope Science Institute (STScI) intends to use the Gaia survey results to improve upon operational aspects such as the guiding and the geometric focal plane characterisation of JWST.
We have undertaken an adaptive optics imaging survey of extra-solar planetary systems and stars showing interesting radial velocity trends from high precision radial velocity searches. Adaptive Optics increases the resolution and dynamic range of an image, substantially improving the detectability of faint close companions. This survey is sensitive to objects less luminous than the bottom of the main sequence at separations as close as 1″. We have detected stellar companions to the planet bearing stars HD 114762 and Tau Boo. We have also detected a companion to the non-planet bearing star 16 Cyg A.
The outstanding feature of the last triennium was most certainly the abrupt generalisation of the use of array detectors, particularly CCDs (charge coupled devices). The latter pervade all subdivisions of instrumental astronomy. The gains achieved by their high quantum efficiency, their stability, their capability of delivering immediately recordable signals which can be processed by appropriate computational means, have been the cause of spectacular progress regarding the photometric precision of weak signal measurements.
A synthesis of the upper Moscovian sedimentological and palaeontological record of terrestrial habitats across the Variscan foreland and adjacent intramontane basins (an area which is referred to here as Variscan Euramerica) suggests a contraction and progressive westward shift of the coal swamps. These changes can be correlated with pulses of tectonic activity (tectonic phases) resulting from the northwards migration of the Variscan Front. This tectonic activity caused disruption to the landscapes and drainage patterns where the coal swamps were growing, which became less suitable to growth of the dominant plants of the swamps, the arborescent lycopsids. They were progressively replaced by vegetation dominated by marattialean ferns, which through a combination of slower growth and larger canopies resulted in less evapo-transpiration. This in turn caused localised reductions in rainfall, which further affected the ability of the lycopsids to dominate the swamp vegetation. These changes were initially localised and where the coal swamps were able to survive the lycopsids and pteridosperms show little change in either species diversity or biogeography, indicating that at this time there was minimal regional-scale climate change taking place. By Asturian times, however, the process had accelerated and the swamps in Variscan Euramerica became progressively replaced by predominantly conifer and cordaite vegetation that favoured much drier substrates. Except in localised pockets in intramontane basins of the Variscan Mountains, the last development of coal swamps in Variscan Euramerica was of early Cantabrian age. Further west, lycopsid-dominated coal swamps persisted for a little longer. The last remnants of the lycopsid-dominated coal swamps in the Illinois Basin disappeared probably by middle-late Cantabrian times, as the cycle of contracting wetlands and regional reductions in rainfall generated its own momentum, and no longer needed the impetus of tectonic instability. This tectonically-driven decline in the Euramerican coal swamps was probably responsible for an annual increase in atmospheric CO2 of c. 0.37 ppm, and may have been implicated in the marked increase in global temperatures near the Moscovian – Kasimovian boundary, and the onset of the Late Pennsylvanian interglacial.
This paper presents the results of the bulk laser damage performance of undoped epoxy thermosets with glassy and rubbery mechanical properties and two commercial polymethylmethacrylate (PMMA) samples. We demonstrate how thermomechanical properties such as glass transition temperature (Tg) and equilibrium shear modulus (Ge) affect laser damage threshold. The rubbery epoxy elastomer shows a damage threshold fluence one order of magnitude higher than PMMA and 2.5 orders of magnitude higher than a glassy epoxy thermoset. A solid-state guest-host limiter is made by doping the epoxy elastomer with zinc octabromotetraphenylporphyrin (ZnOBP). The limiting performance of the elastomer limiter is compared to a solution of ZnOBP and C60 in toluene. Photochemical hysteresis effects in the solid
limiter were also investigated.
Based on the database of 56 supernovae (SNe) events discovered in 3838 galaxies of the southern hemisphere, we compute the rate of SNe of different types along the Hubble sequence normalized to the optical and near-infrared (NIR) luminosities as well as to the stellar mass of the galaxies. We find that the rates of Type Ia SNe show a dependence on both morphology and colors of the galaxies, and therefore, on the star-formation activity. The rate of SNe Ia can be explained by assuming that at least 15% of Ia events in spiral galaxies originate in relatively young stellar populations. We also find that the rates show no modulation with nuclear activity or environment.
To develop novel nonlinear dyes for photonic applications, we synthesized a series of transition metal-containing phenylacetylene oligomers and polymers. The optical properties of these compounds were measured by UV/Vis, fluorescence, and flash photolysis experiments. As the number of oligomer units increased, the transition energies decreased. A solvatochromism experiment suggested the fluorescing state was different from the absorbing state. As a group, the spectra of the polymeric versions of these complexes were red shifted from the spectra of the oligomers. The polymeric complexes had less clear trends relating the number of oligomer units to transition energies. A comparison of a low molecular weight and a high molecular weight polymer showed the degree of polymerization caused spectroscopic shifts comparable to the number of phenylacetylene units in the monomer unit.
Visible light from a copper vapor laser (CVL) operating with 510 and 578 nm radiation (intensity ratio approximately 2:1), an average power of 100 W, a pulse duration of 50 ns, and a repetition frequency of 4.4 kHz has been shown to produce high quality diamond-like-carbon (DLC) films at fluences between 2xl08 and 5xl010 W/cm2. Maximum deposition rates of 2000 μm.cm2/h were obtained at 5xl08 W/cm2. DLC films with hardness values of approximately 60 GPa were characterized by a variety of techniques to confirm DLC character, hydrogen content, and surface morphology. the presence of C2 in the vapor plume was confirmed by the presence of the C2 Swan bands in emission spectra obtained during the process. Economic implications of process scale-up to industrially meaningful component sizes are presented.
Pulsed laser deposition (PLD) has been widely used for deposition of high Tc superconducting thin films, and is recognized as one of the best physical vapor techniques for the preparation of these films. The most important advantage of this technique is stoichiometric deposition; films can be made with the same composition as the target. Utilizing PLD, not only thin films but also multilayers and superlattices of high Tc superconductors have been fabricated. In this paper, the performance of the technique will be reviewed, and speculations regarding the future would be made.
Optical limiting in toluene solutions of substituted benzanthracene- 3,4 diones and three other quinones, namely, benzpyrene-7,8-dione, benzphenanthrene-3,4-dione and chrysene-5,6-dione was investigated at laser wavelengths 532 nm and 694 nm. Low limiting threshold values of the order of 0.01J/cm2 were obtained for some of the quinones at 532nm. Strong triplet-triplet absorption at the excitation laser wavelengths may explain the optical limiting behavior.
A survey study of solvent effects on the linear and nonlinear absorption properties of C60 has been done. The nonlinear absorption measurements are done at 694 nm with a Q-switched Nd:YAG pumped dye laser. In conjunction with this study a three level rate equation system has been solved analytically and the model results used to extract effective excited state cross sections. A difference and a ratio are calculated from the effective excited state cross section and the ground state cross section. The analysis demonstrates that it is this difference and the initial transmission which determine the critical fluence for the onset of nonlinear absorption. The saturation behavior is determined by the ratio of the cross sections and the initial transmission. Based on these findings C60 is shown to have some of the highest reported nonlinear absorption properties at 694 nm. The effective excited state cross sections at 694 nm are reported for the solutions and correlations to the solvent types demonstrated.
Complex formations in C60 solutions have previously been observed in diethylaniline. In a wide survey of solvents conducted in our laboratory, several additional solvents exhibited complexing behavior with C60 when analyzed with UV-Vis and fluorescence spectroscopy. All solvents with complexing behavior contained nitrogen. They are benzonitrile, N-methylpyrrolidone, and triphenylamine. A careful study was done to characterize the formation of the complexes formed in C60/toluene solutions when each complexing agent was added. Diethylaniline was added to the study as a reference complexing system. Formation of the complexes was followed with UV-Vis and fluorescense spectroscopy. Nash plots of the complexes were done to determine the equilibrium constant and the isosbestic point for each system. Nonlinear optical characterization of the complexing solvents was analyzed.
As the minimum dimension of electronic circuits is reduced below one micron, there has been increased interest in developing techniques for fabricating submicron structures. Pb-Sn, Cd-Pb and Al-Al 2Cu eutectic thin films were directionally solidified at rates between .0015 cm/sec and .15 cm/sec with both a lamp and a laser heat source to fabricate fault free submicron periodic structures. A transition from lamellar to cellular structures with increasing solidification rate was observed with a thermal gradient of 200°C/cm applied with the lamp heat source. Cells did not form with the increased thermal gradient produced by the laser heat source, 8000° C/cm. Spacings as fine as .1 micron were observed in the Cd-Pb eutectic. A maximum theoretical growth rate was estimated which corresponds to a spacing of 80A.
Elastic and plastic properties of in situ Cu-based composites with Nb, V, and Fe filaments are reviewed. The evidence is presented for a pronounced size dependence of both the ultimate tensile strength and the Young's moduli. In composites with the smallest filaments (d∼50–200Å) and filament densities as high as 1010/cm2 dislocation density reaches values of 1013 cm/cm3. The yield stress of these samples increases dramatically over the predictions based on the “rule of mixtures” and their ultimate tensile strength approaches the estimated theoretical strength of the material (∼2.7GPa). The observed decrease of Young's modulus as a function of inverse wire diameter in the as-drawn composites is attributed to lattice softening due to high density of extended lattice defects. Upon annealing, Young's modulus increases by as much as 100% and exceeds the maximum values calculated from bulk elastic constants. Possible mechanisms leading to modulus enhancement and to related changes in magnetic and superconducting behavior of in situ composites are discussed.
A challenge exists for wider application of low cost iron-base alloys in the extreme conditions of high temperature, hot corrosion, and high stress experienced in gas turbine engines. In response to this challenge the constitution of the quaternary, Fe-Cr-Mn-C, and to a lesser extent the quinary, Fe-Cr-Mn-Al-C, systems were examined for in situ composite alloy candidates. Multivariant eutectic compositions, determined from phase equilibria, were directionally solidified to produce aligned composites consisting of M7C3 carbides within a gamma iron matrix. The composition and lattice parameters of the carbide and matrix phases were determined to establish their respective stabilities. Stress rupture tests in the direction of phase alignment for certain compositions (e.g., Fe-20 wt% Cr-lO wt% Mn-3.2 wt% C) indicated strength values comparable to cast nickel-base superalloys and exceeded those of the strongest iron-nickel superalloys developed for automotive turbines. Results of cyclic sulfidation testing at 9000 indicated a balance of Cr and Al content to be important to the achievement of outstanding surface stability.