An estimated 0.1 to 0.2% of the North American population is allergic to sesame, and deaths due to anaphylactic shock have been reported. Detecting and quantifying sesame in various food samples is ...critical to safeguard the allergic population by ensuring accurate ingredient labeling. Because of the modular nature of the xMAP Food Allergen Detection Assay (FADA), it was possible through method extension to add sesame as a validated additional analyte. Because raw and toasted sesame are both commonly used and the two display significantly different antigenicity, three antibodies, one monoclonal and two polyclonal, were conjugated to bead sets to ensure reliable detection. The modified xMAP FADA successfully detected sesame incurred or spiked in baked muffins, spice mix, canola oil, and in both raw and toasted sesame oils with limit of quantitation values ≤ 1.3 ppm of sesame. Canola oil, sesame oil, toasted sesame oil, and olive oil inhibited sesame detection, as did the detection of sesame incurred in foods containing oil (e.g., hummus). Despite this inhibition, the xMAP FADA was still able to reliably detect sesame at levels throughout the dynamic range of the assay (22 to 750 ng of protein per mL) in all the foods examined. Further, the high signal-to-noise ratio of the lowest calibration standard and preliminary studies conjugating the antibodies at higher concentrations indicate an ability to increase the sensitivity of the assay should the need arise.
Measurements of the low-z Halpha luminosity function have a large dispersion in the local number density of sources, and correspondingly in the SFR density. The possible causes for these ...discrepancies include limited volume sampling, biases arising from survey sample selection, different methods of correcting for dust obscuration and AGN contamination. The Galaxy And Mass Assembly (GAMA) survey and Sloan Digital Sky Survey (SDSS) provide deep spectroscopic observations over a wide sky area enabling detection of a large sample of star-forming galaxies spanning 0.001<SFR(Halpha)<100 with which to robustly measure the evolution of the SFR density in the low-z universe. The large number of high SFR galaxies present in our sample allow an improved measurement of the bright end of the luminosity function, indicating that the decrease in number density of sources at bright luminosities is best described by a Saunders functional form rather than the traditional Schechter function. This result is consistent with other published luminosity functions in the FIR and radio. For GAMA and SDSS we find the r-band apparent magnitude limit, combined with the subsequent requirement for Halpha detection leads to an incompleteness due to missing bright Halpha sources with faint r-band magnitudes.
We use data from the Herschel-ATLAS to investigate the evolution of the far-infrared–radio correlation over the redshift range 0 < z < 0.5. Using the total far-infrared luminosity of all >5σ sources ...in the Herschel-ATLAS Science Demonstration Field and cross-matching these data with radio data from the Faint Images of the Radio Sky at Twenty-Centimetres (FIRST) survey and the NRAO Very Large Array (VLA) Northern Sky Survey (NVSS), we obtain 104 radio counterparts to the Herschel sources. With these data we find no evidence for evolution in the far-infrared–radio correlation over the redshift range 0 < z < 0.5, where the median value for the ratio between far-infrared and radio luminosity, qIR, over this range is qIR= 2.40 ± 0.12 (and a mean of qIR= 2.52 ± 0.03 accounting for the lower limits), consistent with both the local value determined from IRAS and values derived from surveys targeting the high-redshift Universe. By comparing the radio fluxes of our sample measured from both FIRST and NVSS we show that previous results suggesting an increase in the value of qIR from high to low redshift may be the result of resolving out extended emission of the low-redshift sources with relatively high-resolution interferometric data, although contamination from active galactic nuclei could still play a significant role. We also find tentative evidence that the longer wavelength cooler dust is heated by an evolved stellar population which does not trace the star formation rate as closely as the shorter wavelength ≲ 250 μm emission or the radio emission, supporting suggestions based on detailed models of individual galaxies.
We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust, \tau^f_B, and the stellar mass surface density, \mu_{*}, of nearby (z < 0.13) spiral ...galaxies: log(\tau^f_B) = 1.12(+-0.11)log(\mu_{*}/M_sol kpc^2)-8.6(+-0.8). This relation was derived from a sample of spiral galaxies taken from the Galaxy and Mass Assembly (GAMA) survey and detected in the FIR/submm in the Herschel-ATLAS survey. Using a quantitative analysis of the NUV attenuation-inclination relation for complete samples of GAMA spirals categorized according to \mu_{*} we demonstrate that this correlation can be used to statistically correct for dust attenuation purely on the basis of optical photometry and S'ersic-profile morphological fits. Considered together with previously established empirical relationships between stellar mass, metallicity and gas mass, the near linearity and high constant of proportionality of the \tau^f_B-\mu_{*} relation disfavors a stellar origin for the bulk of refractory grains in spiral galaxies, instead being consistent with the existence of a ubiquitous and very rapid mechanism for the growth of dust in the ISM. We use the \tau^f_B-\mu_{*} relation in conjunction with the radiation transfer model for spiral galaxies of Popescu & Tuffs (2011) to derive intrinsic scaling relations between specific star formation rate (sSFR), stellar mass, and \mu_{*}, in which the attenuation of the UV light used to measure the SFR is corrected on an object-to-object basis. A marked reduction in scatter in these relations is achieved which is demonstrably due to correction of both the inclination-dependent and face-on components of attenuation. Our results are consistent with a picture of spiral galaxies in which most of the submm emission originates from grains residing in translucent structures, exposed to UV in the diffuse interstellar radiation field.
SARS-CoV-2 is known to transmit in hospital settings, but the contribution of infections acquired in hospitals to the epidemic at a national scale is unknown.
We used comprehensive national English ...datasets to determine the number of COVID-19 patients with identified hospital-acquired infections (with symptom onset > 7 days after admission and before discharge) in acute English hospitals up to August 2020. As patients may leave the hospital prior to detection of infection or have rapid symptom onset, we combined measures of the length of stay and the incubation period distribution to estimate how many hospital-acquired infections may have been missed. We used simulations to estimate the total number (identified and unidentified) of symptomatic hospital-acquired infections, as well as infections due to onward community transmission from missed hospital-acquired infections, to 31st July 2020.
In our dataset of hospitalised COVID-19 patients in acute English hospitals with a recorded symptom onset date (n = 65,028), 7% were classified as hospital-acquired. We estimated that only 30% (range across weeks and 200 simulations: 20-41%) of symptomatic hospital-acquired infections would be identified, with up to 15% (mean, 95% range over 200 simulations: 14.1-15.8%) of cases currently classified as community-acquired COVID-19 potentially linked to hospital transmission. We estimated that 26,600 (25,900 to 27,700) individuals acquired a symptomatic SARS-CoV-2 infection in an acute Trust in England before 31st July 2020, resulting in 15,900 (15,200-16,400) or 20.1% (19.2-20.7%) of all identified hospitalised COVID-19 cases.
Transmission of SARS-CoV-2 to hospitalised patients likely caused approximately a fifth of identified cases of hospitalised COVID-19 in the "first wave" in England, but less than 1% of all infections in England. Using time to symptom onset from admission for inpatients as a detection method likely misses a substantial proportion (> 60%) of hospital-acquired infections.
We determine the low-redshift field galaxy stellar mass function (GSMF) using an area of 143 deg^2 from the first three years of the Galaxy And Mass Assembly (GAMA) survey. The magnitude limits of ...this redshift survey are r < 19.4 mag over two thirds and 19.8 mag over one third of the area. The GSMF is determined from a sample of 5210 galaxies using a density-corrected maximum volume method. This efficiently overcomes the issue of fluctuations in the number density versus redshift. With H_0 = 70, the GSMF is well described between 10^8 and 10^11.5 Msun using a double Schechter function with mass^* = 10^10.66 Msun, phi_1^* = 3.96 x 10^-3 Mpc^-3, alpha_1 = -0.35, phi_2^* = 0.79 x 10^-3 Mpc^-3 and alpha_2 = -1.47. This result is more robust to uncertainties in the flow-model corrected redshifts than from the shallower Sloan Digital Sky Survey main sample (r < 17.8 mag). The upturn in the GSMF is also seen directly in the i-band and K-band galaxy luminosity functions. Accurately measuring the GSMF below 10^8 Msun is possible within the GAMA survey volume but as expected requires deeper imaging data to address the contribution from low surface-brightness galaxies.
With reports of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) continuing to increase and therapeutic options decrease, infection control methods are of increasing importance. ...Here we investigate the relationship between surveillance and infection control. Surveillance plays two roles with respect to control: it allows detection of infected/colonized individuals necessary for their removal from the general population, and it allows quantification of control success. We develop a stochastic model of MRSA transmission dynamics exploring the effects of two screening strategies in an epidemic setting: random and on admission. We consider both hospital and community populations and include control and surveillance in a single framework. Random screening was more efficient at hospital surveillance and allowed nosocomial control, which also prevented epidemic behaviour in the community. Therefore, random screening was the more effective control strategy for both the hospital and community populations in this setting. Surveillance strategies have significant impact on both ascertainment of infection prevalence and its control.
The Galaxy And Mass Assembly (GAMA) survey is a multiwavelength photometric and spectroscopic survey, using the AAOmega spectrograph on the Anglo-Australian Telescope to obtain spectra for up to ...~300000 galaxies over 280 square degrees, to a limiting magnitude of r_pet < 19.8 mag. The target galaxies are distributed over 0<z<0.5 with a median redshift of z~0.2, although the redshift distribution includes a small number of systems, primarily quasars, at higher redshifts, up to and beyond z=1. The redshift accuracy ranges from sigma_v~50km/s to sigma_v~100km/s depending on the signal-to-noise of the spectrum. Here we describe the GAMA spectroscopic reduction and analysis pipeline. We present the steps involved in taking the raw two-dimensional spectroscopic images through to flux-calibrated one-dimensional spectra. The resulting GAMA spectra cover an observed wavelength range of 3750<lambda<8850 A at a resolution of R~1300. The final flux calibration is typically accurate to 10-20%, although the reliability is worse at the extreme wavelength ends, and poorer in the blue than the red. We present details of the measurement of emission and absorption features in the GAMA spectra. These measurements are characterised through a variety of quality control analyses detailing the robustness and reliability of the measurements. We illustrate the quality of the measurements with a brief exploration of elementary emission line properties of the galaxies in the GAMA sample. We demonstrate the luminosity dependence of the Balmer decrement, consistent with previously published results, and explore further how Balmer decrement varies with galaxy mass and redshift. We also investigate the mass and redshift dependencies of the NII/Halpha vs OIII/Hbeta spectral diagnostic diagram, commonly used to discriminate between star forming and nuclear activity in galaxies.
We present two large, nearby (0.013 ≤ z ≤ 0.06) samples of early-type galaxies (ETGs): a visually classified sample of 220 ETGs, created using source-matched data from the Galaxy and Mass Assembly ...(GAMA) data base with far-infrared/submm detections from Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS); and a visually classified sample of 551 ETGs which are undetected with H-ATLAS. Active galactic nuclei are removed from our samples using optical emission-line diagnostics. These samples are scrutinized to determine characteristics of submm detected versus undetected ETGs. We find similarities in the stellar mass distributions of the two ETG samples but testing other properties uncovers significant differences. The submm detected sample is shown to have lower concentration and Sérsic indices than those in the undetected sample - a result which may be linked to the presence of dust in the former. Optical and ultraviolet-optical colours are also shown to be much bluer, indicating that the dust is linked with recent star formation. The intrinsic effective radii are on average 1.5 times larger for the submm detected ETGs. Surface densities and groups data from the GAMA data base are examined for the two samples, leading to the conclusion that dusty ETGs inhabit sparser environments than non-dusty ETGs in the nearby Universe, although environments of the brightest ETGs are shown to differ the least. Modified Planck functions are fit to the H-ATLAS detected Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) fluxes for ETGs with submm flux densities of at least 3σ in the 350 μm SPIRE band, giving a resultant mean cold dust temperature of T
d = 22.1 K, with a range of 9-30 K. The corresponding mean dust mass is 1.8 × 107 M, with a range of (0.08-35.0) × 107 M. The dust masses calculated from these fits, normalized by stellar mass, are shown to increase with decreasing stellar mass and bluer colours. Based on visual classifications of elliptical and lenticular, we find similar dust properties for these two early-type morphologies. We conclude that there is a population of elliptical galaxies which exhibit larger dust masses, lower Sérsic index and bluer colours than the more well-known, massive, red population of ellipticals.
Recently a number of studies have proposed that the dispersion along the star
formation rate - stellar mass relation ($\sigma_{\mathrm{sSFR}}$-M$_{*}$) is
indicative of variations in star-formation ...history (SFH) driven by feedback
processes. They found a 'U'-shaped dispersion and attribute the increased
scatter at low and high stellar masses to stellar and active galactic nuclei
feed-back respectively. However, measuring $\sigma_{\mathrm{sSFR}}$ and the
shape of the $\sigma_{\mathrm{sSFR}}$-M$_{*}$ relation is problematic and can
vary dramatically depending on the sample selected, chosen separation of
passive/star-forming systems, and method of deriving star-formation rates
($i.e.$ H$\alpha$ emission vs spectral energy distribution fitting). As such,
any astrophysical conclusions drawn from measurements of
$\sigma_{\mathrm{sSFR}}$ must consider these dependencies. Here we use the
Galaxy And Mass Assembly survey to explore how $\sigma_{\mathrm{sSFR}}$ varies
with SFR indicator for a variety of selections for disc-like `main sequence'
star-forming galaxies including colour, star-formation rate, visual morphology,
bulge-to-total mass ratio, S\'{e}rsic index and mixture modelling. We find that
irrespective of sample selection and/or SFR indicator, the dispersion along the
sSFR-M$_{*}$ relation does follow a 'U'-shaped distribution. This suggests that
the shape is physical and not an artefact of sample selection or method. We
then compare the $\sigma_{\mathrm{sSFR}}$-M$_{*}$ relation to state-of-the-art
hydrodynamical and semi-analytic models and find good agreement with our
observed results. Finally, we find that for group satellites this 'U'-shaped
distribution is not observed due to additional high scatter populations at
intermediate stellar masses.
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