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Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166–0·325) and England & Wales (0·213, 95% CI 0·156–0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.
This observational study aims to investigate the microbiological quality of commercially prepared lightly cooked foods with a major component of food of animal origin and collected as would be served to a consumer. A total of 356 samples were collected from catering (92%), retail (7%) or producers (1%) and all were independent of known incidents of foodborne illness. Using standard methods, all samples were tested for: the presence of Campylobacter spp. and Salmonella spp. and enumerated for levels of, Bacillus spp. including B. cereus, Clostridium perfringens, Listeria spp. including L. monocytogenes, Staphylococcus aureus, Escherichia coli, Enterobacteriacea and aerobic colony count (ACC). Results were interpreted as unsatisfactory, borderline or satisfactory according to the Health Protection Agency guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market. Amongst all samples, 70% were classified as satisfactory, 18% were borderline and 12% were of unsatisfactory microbiological quality. Amongst the unsatisfactory samples, six (2%) were potentially injurious to health due to the presence of: Salmonella spp. (one duck breast); Campylobacter spp. (two duck breast and one chicken liver pâté); L. monocytogenes at 4·3 × 103 cfu (colony-forming units)/g (one duck confit with foie gras ballotin) and C. perfringens at 2·5 × 105 cfu/g (one chicken liver pâté). The remaining unsatisfactory samples were due to high levels of indicator E. coli, Enterobacteriaceae or ACC.
Most of the atomic species originating in the solar atmosphere between the upper chromosphere and the corona have their strong characteristic wavelengths in the extreme ultraviolet region of the spectrum. A simple normal-incidence spectrometer system with solar blind detectors such as the Harvard instrument operating between approximately 250 Å and 1350 Å is ideally suited for observing in this most interesting range of the solar atmosphere where the temperature rises outward from 104 to 3 × 106 K. The temperature range represented by the various atomic and ionic species in the extreme ultraviolet is associated with many types of solar structure, prominences and filaments, the supergranulation cells and network, active regions and their associated loop structures and other features. Simultaneous observations in lines of different characteristic temperatures provide a three-dimensional probe of the solar atmosphere. In the instrument, the principal polychromatic position observes the Lyman continuum, Lα, C II, C III, O IV, O VI, and Mg x with seven detectors simultaneously from the same spatial image element, 5″ in size. Approximately 60 additional polychromatic positions are used routinely to carry out specific observing programs, for example, covering several lines of a given stage of ionization, observing lines or continuum from specific species of interest such as helium in prominences, comparing combinations of lines from a given ionic species such as O v where the relative intensities give a rather direct measurement of the density at a given temperature, or measuring differing positions in the Lyman continuum providing intensity measurements which can be interpreted in terms of the departure from ionization equilibrium.
We compare the results of using a Random Forest Classifier with the results of using Nonparametric Discriminant Analysis to classify whether a filament channel (in the case of a filament eruption) or an active region (in the case of a flare) is about to produce an event. A large number of descriptors are considered in each case, but it is found that only a small number are needed in order to get most of the improvement in performance over always predicting the majority class. There is little difference in performance between the two classifiers, and neither results in substantial improvements over simply predicting the majority class.
A nationwide initiative was implemented in February 2014 to decrease Clostridium difficile infections (CDI) in Veterans Affairs (VA) long-term care facilities. We report a baseline of national CDI data collected during the 2 years before the Initiative.
Personnel at each of 122 reporting sites entered monthly retrospective CDI case data from February 2012 through January 2014 into a national database using case definitions similar to those used in the National Healthcare Safety Network Multidrug-Resistant Organism/CDI module. The data were evaluated using Poisson regression models to examine infection occurrences over time while accounting for admission prevalence and type of diagnostic test.
During the 24-month analysis period, there were 100,800 admissions, 6,976,121 resident days, and 1,558 CDI cases. The pooled CDI admission prevalence rate (including recurrent cases) was 0.38 per 100 admissions, and the pooled nonduplicate/nonrecurrent community-onset rate was 0.17 per 100 admissions. The pooled long-term care facility–onset rate and the clinically confirmed (ie, diarrhea or evidence of pseudomembranous colitis) long-term care facility–onset rate were 1.98 and 1.78 per 10,000 resident days, respectively. Accounting for diagnostic test type, the long-term care facility–onset rate declined significantly (P=.05), but the clinically confirmed long-term care facility–onset rate did not.
VA long-term care facility CDI rates were comparable to those in recent reports from other long-term care facilities. The significant decline in the long-term care facility-onset rate but not in the clinically confirmed long-term care facility–onset rate may have been due to less testing of asymptomatic patients. Efforts to decrease CDI rates in long-term care facilities are necessary as part of a coordinated approach to decrease healthcare-associated infections.
Infect. Control Hosp. Epidemiol. 2016;37(3):295–300
In this paper we review some preliminary results from the Harvard College Observatory Extreme Ultraviolet Spectroheliometer on ATM that pertain to solar activity. The results reviewed here are described in more detail in other papers referred to in the text. In the following paragraphs we first describe the instrument and its capabilities, and then turn to results on active regions, sunspots, flares, EUV bright points, coronal holes, and prominences.
This paper departs somewhat from the usual interpretation of the subject of this symposium, in which instrumental techniques normally deal with diverse aspects of experiment design or construction. Rather, we will concern ourselves here with some innovations in the ground control optimization of the modes of data acquisition once an instrument is in orbit. Although the fullest possible utilization of the data gathering capability of a device is of vital interest to the success of the experiment and the mission, the subject has not been discussed at length in the open forum of scientific meetings. The planning of the data gathering and processing aspects of a mission must receive as careful attention as instrument design and test if the characteristics of the instrument are to be fully exploited.
This monograph summarizes the proceedings of a roundtable meeting convened to discuss pseudobulbar affect (PBA). Two didactic lectures were presented, followed by a moderated discussion among 11 participants. Post-meeting manuscript development synthesized didactic- and discussion-based content and incorporated additional material from the neuroscience literature. A conceptual framework with which to distinguish between disorders of mood and affect is presented first, and disorders of affect regulation are then reviewed briefly. A detailed description of the most common of these disorders, PBA, is the focus of the remainder of the monograph. The prevalence, putative neuranatomic and neurochemical bases of PBA are reviewed, and current and emerging methods of evaluation and treatment of persons with PBA are discussed. The material presented in this monograph will help clinicians better recognize, diagnose, and treat PBA, and will form a foundation for understanding and interpreting future studies of this condition.
Energetically-deposited carbon contacts to n-type 6H-SiC have exhibited either insulating, rectifying or ohmic electrical characteristics depending on the average energy of the depositing flux and the substrate temperature. Deposition at room temperature and at a low-medium average energy (<500 eV) has resulted in carbon with a low graphitic content and insulating electrical contacts. With higher average energy and at a moderately elevated temperature (∼100 °C), the higher graphitic content contacts were rectifying with an ideality factor, η, of ∼1.8 and barrier height of ∼0.88 eV. Oriented graphitic carbon deposited at 200 °C with biases exceeding 300 V formed ohmic contacts.
Recent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).
The compatibility of both bulk and porous silicon at the subcutaneous site has been assessed for the first time, following ISO standard procedures. The in-vivo responses to implantation were monitored in the guinea pig and histopathological reactions evaluated at 1, 4, 12 and 26 weeks. Attention is focused here on the histological assessment protocols used, and the results demonstrating in-vivo evidence for good tissue compatibility, and porous Si bioactivity with regards calcification.
In this study, the authors focused on children from 2-8 years of age and asked the simple question: what do engineers do? The number one response was: “I don’t know”, the number two response was “they drive a train.” While children are very familiar with professionals such as doctors, teachers, nurses, firefighters and policemen, they are rarely introduced to engineers. With this motivation, the authors developed a novel children’s book on engineering: Engineering Elephants. This book is an outreach tool that introduces children to the dynamic world of engineering design through roller coasters, fireworks, and a plethora of other exciting adventures. The book teaches children about relevant topics such as nanotechnology, renewable energy, and prosthetics by engaging them through an interactive journey of an elephant and his questioning of the world around him. The text was strategically developed using the language of science (asking questions) and introducing vocabulary relevant to science and math using a lyrical pattern. This presentation will highlight the development of this book as an instructional aid but also detail the response of various age groups to engineering activities presented as a companion to this book. In particular, an elementary school district in West Texas designed a 4-5th grade 3-week summer school curriculum around this book. Results from this study will have an impact on future generations by inspiring them to consider the exciting profession of engineering at an early age.
Measurements are presented which show the effect of proton irradiation on the irreversibility line and critical current in Tl2 CaBa2Cu2O8 thin films. These data show that the irreversibility line is dependent on the defect structure and that the pinning energy is increased by proton irradiation. This leads to an increase in the critical current density at 60 K for the lowest radiation dose. Further irradiation reduces the critical current, even while the irreversibility line is enhanced.
Films of Y1Ba2Cu3O7-y have been grown by off-axis DC sputtering onto substrates of (100) SrTiO3. LaAlO, LaGaO3, Yttria-stabilized Zirconia, and MgO. Our best films, grown on SrTiO3 substrates at a temperature of 650°C and a sputtering pressure of 100 mTorr (consisting of 80 mTorr Ar and 20 mTorr O2) have room temperature resistivities of 280 μΩ-cm, an inductive Tcof 88 K and an inductive Jc 'Sof∼ 2.6 × 106 A/cm2 at 77 K and 3.9 × 107 A/cm2at 4.2 K. Films grown on YSZ tend to have higher resistivities (∼ 600 μΩ-cm) but still have Tc's of 86 K and Jc's of - 106 A/cm2 at 77 K. Films down to 550 Å still have Tc's of 86 K and Jc's at 77 K > 106 A/cm2. Films grown at lower temperatures (600°C) on S1TiO3 begin to show a-axis growth, but the superconducting properties deteriorate.
InP/In0.53Ga0.47As heterojunction bipolar transistors with high current gain for optoelectronic applications place stringent requirements on the ohmic contact to the base layer of moderately doped (p < 1×1019 cm−3) In0.53Ga0.47As. Contact resistivity should be <l×10−6 Ωcm2 and low depth of penetration is necessary considering the small base thickness of approximately 100 nm. The authors have recently presented data on Pd/Zn/Au/LaB6/Au contacts on p-In0.53Ga0.47As (doped to 4×1018 cm−3) with low contact resistivities of l×10−6 Ωcm2. In this paper, details are given on the optimization of the contact composition and annealing conditions of the metallization that resulted in shallow and low-resistive contacts. Alternatively, it is shown that Au-free Pd/Zn/Sb/Pd contacts on p-In0.53Ga0.47As have exhibited even lower resistivities, i.e. 3-6×10−7 Ωcm2. Backside SIMS measurements revealed a depth of penetration as low as 20 nm for this contact scheme. Aging tests at temperatures of 300 - 400 °C have demonstrated that the electrical characteristics of both types of metallization were sufficiently stable to withstand the typical processing steps for device passivation.
The response of a range of porous Si and poly Si films to storage in acellular simulated body fluids is summarised and its implications discussed. It is suggested that the combination of VLSI technology, micromachining and surface microstructuring achievable with silicon, could establish this prominent semiconductor as a very useful biomaterial by the next century. The ‘biocompatibility’ of a variety of silicon microstructures, and even bulk silicon has received surprisingly little study, but now warrants detailed in-vitro and in-vivo assessment.
The growth of nanostructured material continues to attract attention for a number of applications, including highly sensitive gas sensors (due to the increased surface area), and photonic crystals (which require arrays of nanostructures). Even though nanostructures can be formed through self-assembly, they often do not possess the high crystal quality of those grown using vapour liquid solid (VLS) techniques; also, with VLS the feature size and placement can be easily controlled. To achieve VLS growth, however, several parameters have to be considered specific to the material of interest. In this study, we examine VLS growth of both InN (infrared) and ZnO (ultraviolet) nanostructures.
InN continues to be a topic of great interest, particularly with respect to the issues surrounding its bandgap energy. To further explore this material and its properties, we have grown 200–300 nm InN films by a plasma-assisted molecular beam epitaxy (PAMBE) technique on a variety of substrates, including (0001) sapphire, (100) InAs, and both (100) and (111) YSZ. Single-crystal films regardless of quality all show the commonly reported broad luminescence feature in the range of 0.7 to 0.8 eV, although we have also observed this feature in polycrystalline films. Growth on (100) InAs and (100) YSZ was motivated by a desire to explore cubic InN; in both cases growth appears to be initially cubic, but a mixture of hexagonal and cubic phases is detected in the final layer.
Active nitrogen species produced by an Oxford Applied Research HD-25 plasma source have been monitored by optical emission spectroscopy and quadrapole mass spectroscopy. Both techniques confirmed that at higher RF powers and lower flow rates the efficiency of atomic nitrogen production increased; emission spectroscopy confirmed that this was at the expense of active molecular nitrogen (N2*). InN films grown on (0001) sapphire/GaN with higher relative molecular content were found to have lower carrier concentrations than the corresponding films grown with higher atomic content. However, electrical properties of films grown on (111) YSZ showed insensitivity to the active nitrogen content. Etching experiments revealed that films grown on sapphire/GaN were nitrogen-polar, while films grown on YSZ were In-polar, suggesting that film polarity can greatly influence the effect active species have on growth. Lattice relaxation, as measured by reflection high-energy electron diffraction, revealed that the N-polar films grown under high relative molecular flux relaxed fully after ∼60 nm of growth, while the corresponding In-polar film relaxed fully within the first several nm of growth.