Campylobacter is a major cause of food poisoning and is typically the most common cause of gastroenteritis in the UK. Data collected at broiler farm and abattoir level, for slaughter batches that ...were sampled for UK‐wide monitoring, were used to generate two epidemiological risk factor models. A total of 483 batches slaughtered between January 2016 and March 2017 were used in the analysis, coming from 19 abattoirs representing more than 85% of UK broiler production. For each selected slaughter batch, one carcase was sampled after primary chilling and 10 randomly sampled birds had caecal samples collected at the evisceration point. Samples were used for Campylobacter identification and quantification. Two multivariable mixed‐effects models were designed, one with the binary outcome for the detection of a highly contaminated (>1000 colony forming units (CFU)/g) Campylobacter‐positive carcase, whereas the other used the Campylobacter colony count (CFU/g) carcase outcome. The results suggest that caecal colonization within the batch was a key factor for the occurrence of Campylobacter on carcases, and many factors that were identified in the model were also likely to be related to colonization or related to the risk of introduction of Campylobacter from partial depopulation (referred to as thinning) of ~30% of the flock approximately 1 week before full flock depopulation events. The amount of neck skin in the sample was another key factor identified and was included in both models as a risk factor. The models have also identified other factors which may be related to the general health and husbandry on‐farm (use of prebiotics or vaccines, and identification of the product used for drinking line cleaning), whereas the other factors may identify control points related to transmission within a farm. The identification of these variables could help focus control efforts on‐farm, especially for relatively easy improvements, such as improving the provision of house‐specific bird‐weighing buckets/cages in houses.
Aims: To determine the fate of Escherichia coli deposited onto grassland via faeces, from naturally colonized cattle, sheep or pigs.
Methods and Results: Groups of cattle, sheep and pigs were ...penned outdoors on grass during November, and removed after 14 days. Escherichia coli populations in the ground declined over 134 days from initial average levels of 5·34, 4·31 and 4·96 log10 CFU g−1 in cattle, sheep and pig pens, respectively. The maximum Escherichia coli survival time was up to 162 days (190 days taking sampling interval and deposition time into account), but numbers varied significantly amongst the 20 replicates taken each day. Escherichia coli originating from cattle and sheep had average decimal reduction times (D‐values) of 38 and 36 days, respectively; E. coli originating from pigs declined significantly faster (average D‐value of 26 days).
Significance and Impact of the Study: Escherichia coli from livestock faeces can survive on grass for at least 5–6 months, affording opportunity for pathogenic biotypes to contaminate animals, plants or water.
ObjectivesFew studies reported COVID-19 cases in schools during the 2020/21 academic year in a setting of uninterrupted in-person schooling. The main objective was to determine the SARS-CoV-2 ...seroprevalence among school staff in Vancouver public schools.DesignCumulative incident COVID-19 cases among all students and school staff based on public health data, with an embedded cross-sectional serosurvey among a school staff sample that was compared to period, age, sex and geographical location-weighted data from blood donors.SettingVancouver School District (British Columbia, Canada) from kindergarten to grade 12.ParticipantsActive school staff enrolled from 3 February to 23 April 2021 with serology testing from 10 February to 15 May 2021.Main outcome measuresSARS-CoV-2 seroprevalence among school staff, based on spike (S)-based (unvaccinated staff) or N-based serology testing (vaccinated staff).ResultsPublic health data showed the cumulative incidence of COVID-19 among students attending in-person was 9.8 per 1000 students (n=47 280), and 13 per 1000 among school staff (n=7071). In a representative sample of 1689 school staff, 78.2% had classroom responsibilities, and spent a median of 17.6 hours in class per week (IQR: 5.0–25 hours). Although 21.5% (363/1686) of surveyed staff self-reported close contact with a COVID-19 case outside of their household (16.5% contacts were school-based), 5 cases likely acquired the infection at school based on viral testing. Sensitivity/Specificity-adjusted seroprevalence in 1556/1689 staff (92.1%) was 2.3% (95% CI: 1.6% to 3.2%), comparable to a sex, age, date and residency area-weighted seroprevalence of 2.6% (95% CI: 2.2% to 3.1%) among 5417 blood donors.ConclusionSeroprevalence among staff was comparable to a reference group of blood donors from the same community. These data show that in-person schooling could be safely maintained during the 2020/21 school year with mitigation measures, in a large school district in Vancouver, Canada.
To assess the risks of zoonotic agents in dissemination of livestock wastes into the environment by airborne distribution. To subsequently assess the survival time of zoonotic agents, introduced in ...irrigation water, on the phylloplane of produce. An Escherichia coli marker was introduced into pig slurry which was spread using a rain gun sprayer. Air sampling was undertaken to determine the distance reached by the marker. No recoveries were observed at a distance of 250 m. Borehole water, contaminated with zoonotic agents, was used to irrigate field plots sown with lettuce and spinach. Decline in bacterial numbers on the phylloplane was observed with time. After initial rapid decreases, we were unable to detect any pathogen from the phylloplane, 1 month after contamination. These preliminary results suggest that the risks to public health from the aerosolized spread of bacteria during slurry spreading by rain gun are low. Although, zoonotic agents on crop phylloplanes perish quickly, the risks of overhead irrigation of fresh produce 3 weeks before harvest should still be considered. These preliminary results improve our understanding on the fate of zoonotic agents in the environment. Spreading liquid livestock wastes by an airborne mechanism may not pose a significant public health risk. Detection of zoonotic agents 3 weeks after contamination of lettuce and spinach means that consideration should be given by the farmers until the time of harvest, when irrigating fresh produce with water that may have been directly or indirectly contaminated by livestock wastes.
The carbon and nitrogen isotope values of mantle xenoliths and xenocrysts are used to trace the cycling of volatiles in the deep Earth, for example, to place empirical constraints on the origin of ...diamond-forming carbon in the mantle. The global database for diamond shows that the δ13C value of peridotitic diamonds is very narrow, typically around −5‰, whereas eclogitic diamonds can show positive and very negative δ13C values resembling crustal carbonates and crustal organic carbon (<−40 to >+2‰); commonly interpreted to reflect a relationship between eclogitic diamond formation and subduction zone planet tectonics. Curiously, diamonds from both parageneses can show positive (crust-like) and negative (mantle-like) δ15N values (from <−40 to >+20‰). Most of these data are derived from single stage combustion gas sourced mass spectrometry, which produces simplistic datasets. By fragmenting single diamonds or using in-situ ion-beam techniques it is known that single diamonds can show large-scale heterogeneity for their carbon isotope values and nitrogen abundances, sometimes as large as entire populations of diamond across a few hundred micrometres. What is less well known is the scale of nitrogen isotope heterogeneity within single diamonds, and if the nitrogen isotope heterogeneity of single diamonds can provide an insight into why diamonds that show very restricted δ13C values show a much large range of δ15N values.
To investigate the scale, and to determine the origin of the nitrogen isotope heterogeneity (source vs. fractionation during diamond-formation) shown for populations of mantle diamonds we have determined multiple δ13C–δ15N values and nitrogen abundances from 14 monocrystalline (MCDs) and 25 polycrystalline diamonds (PCDs) using step-wise oxidation gas sourced mass spectrometry. These data show that the heterogeneity shown for carbon and nitrogen isotope values from single diamond samples presented here is typically <5‰ and <8‰ respectively, both of which are comparable to the standard deviation for the mean mantle δ13C and δ15N values (±3 and ±4‰). However, there are samples that show much larger heterogeneities for δ13C and δ15N values (≤23‰ and ≤33‰ respectively), which cannot be generated by equilibrium stable isotope fractionation during, or prior to diamond-formation. These data suggest that isotopic heterogeneity may be present within the diamond-forming fluid on sub-mm scale, or that these diamonds formed during multiple diamond-formation events from isotopically distinct sources. From these 39 samples there are only 5 PCDs that show a larger range of carbon isotopes relative to nitrogen isotopes, but of these 5 samples only 2 show a range of δ13C values outside of analytical uncertainty. The remaining 34 samples show a greater isotopic heterogeneity for δ15N relative to δ13C values. The samples with the largest carbon and nitrogen isotopic heterogeneity are also the samples with low-bulk δ13C values (<−10‰), whilst there is no relationship between the ranges of nitrogen isotope values for a given sample and the corresponding bulk δ15N value or nitrogen content.
These data show that δ15N values recorded in mantle diamonds are relatively heterogeneous, and can show both mantle-like (negative) and crustal (sedimentary)-like (positive) δ15N values within the same sample. We conclude that the large range of nitrogen isotope values seen within individual diamonds means that the observation of negative, mantle-like, nitrogen in mantle diamonds acquired by single-stage bulk combustion isotope ratio mass spectrometry cannot be used as a conclusive indicator for a mantle origin for the entirety of the diamond-forming carbon, and vice versa. Also, the behaviour of 15N/14N is not coupled with the behaviour of 14N/12C during diamond-formation. Instead, it appears that diamond-forming fluids can have positive and negative δ15N values, irrespective of their δ13C value(s). These data suggest that subduction induced nitrogen isotope heterogeneity may not be coupled with subduction induced carbon isotope heterogeneity in diamond-forming fluids.
•Individual diamonds show heterogeneity for N contents and C–N isotopes.•On average, the N isotope variability is far greater than C isotope variability.•Subduction induced N isotope heterogeneity is not coupled to C isotope heterogeneity.•N/C and 15N/14N appear decoupled during diamond formation.
X-ray Free Electron Lasers (XFELs) allow the collection of high-quality serial femtosecond crystallography data. The next generation of megahertz superconducting FELs promises to drastically reduce ...data collection times, enabling the capture of more structures with higher signal-to-noise ratios and facilitating more complex experiments. Currently, gas dynamic virtual nozzles (GDVNs) stand as the sole delivery method capable of best utilizing the repetition rate of megahertz sources for crystallography. However, their substantial sample consumption renders their use impractical for many protein targets in serial crystallography experiments. Here, we present a novel application of a droplet-on-demand injection method, which allowed operation at 47 kHz at the European XFEL (EuXFEL) by tailoring a multi-droplet injection scheme for each macro-pulse. We demonstrate a collection rate of 150 000 indexed patterns per hour. We show that the performance and effective data collection rate are comparable to GDVN, with a sample consumption reduction of two orders of magnitude. We present lysozyme crystallographic data using the Large Pixel Detector at the femtosecond x-ray experiment endstation. Significant improvement of the crystallographic statistics was made by correcting for a systematic drift of the photon energy in the EuXFEL macro-pulse train, which was characterized from indexing the individual frames in the pulse train. This is the highest resolution protein structure collected and reported at the EuXFEL at 1.38 Å resolution.
Pemphigus vulgaris (PV) is an IgG autoantibody-mediated, potentially fatal mucocutaneous disease manifested by progressive non-healing erosions and blisters. Beyond acting to inhibit adhesion ...molecules, PVIgGs elicit a unique process of programmed cell death and detachment of epidermal keratinocytes termed apoptolysis. Mitochondrial damage by antimitochondrial antibodies (AMA) has proven to be a critical link in this process. AMA act synergistically with other autoantibodies in the pathogenesis of PV. Importantly, absorption of AMA inhibits the ability of PVIgGs to induce blisters. Pharmacologic agents that protect mitochondrial function offer a new targeted approach to treating this severe immunoblistering disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
levels on chicken neck and breast skin were compared. Neck skin was significantly more contaminated (
< 0.05) than breast skin. No relationship between the two skin types was found for
levels. A UK ...government reduction target for highly contaminated chicken was not achieved.
To compare test results from second-generation Frequency-Doubling Technology perimetry (FDT2, Humphrey Matrix; Carl-Zeiss Meditec, Dublin, CA) and standard automated perimetry (SAP) in patients with ...glaucoma. Specifically, to examine the relationship between visual field sensitivity and test-retest variability and to compare total and pattern deviation probability maps between both techniques.
Fifteen patients with glaucoma who had early to moderately advanced visual field loss with SAP (mean MD, -4.0 dB; range, +0.2 to -16.1) were enrolled in the study. Patients attended three sessions. During each session, one eye was examined twice with FDT2 (24-2 threshold test) and twice with SAP (Swedish Interactive Threshold Algorithm SITA Standard 24-2 test), in random order. We compared threshold values between FDT2 and SAP at test locations with similar visual field coordinates. Test-retest variability, established in terms of test-retest intervals and standard deviations (SDs), was investigated as a function of visual field sensitivity (estimated by baseline threshold and mean threshold, respectively). The magnitude of visual field defects apparent in total and pattern deviation probability maps were compared between both techniques by ordinal scoring.
The global visual field indices mean deviation (MD) and pattern standard deviation (PSD) of FDT2 and SAP correlated highly (r > 0.8; P < 0.001). At test locations with high sensitivity (>25 dB with SAP), threshold estimates from FDT2 and SAP exhibited a close, linear relationship, with a slope of approximately 2.0. However, at test locations with lower sensitivity, the relationship was much weaker and ceased to be linear. In comparison with FDT2, SAP showed a slightly larger proportion of test locations with absolute defects (3.0% vs. 2.2% with SAP and FDT2, respectively, P < 0.001). Whereas SAP showed a significant increase in test-retest variability at test locations with lower sensitivity (P < 0.001), there was no relationship between variability and sensitivity with FDT2 (P = 0.46). In comparison with SAP, FDT2 exhibited narrower test-retest intervals at test locations with lower sensitivity (SAP thresholds <25 dB). A comparison of the total and pattern deviation maps between both techniques showed that the total deviation analyses of FDT2 may slightly underestimate the visual field loss apparent with SAP. However, the pattern-deviation maps of both instruments agreed well with each other.
The test-retest variability of FDT2 is uniform over the measurement range of the instrument. These properties may provide advantages for the monitoring of patients with glaucoma that should be investigated in longitudinal studies.
Estimating the effect of official foreign exchange market intervention is complicated by the fact that intervention at any point entails a “self-selection” choice made by the authorities and that no ...counterfactual is observed. To address these issues, we estimate the “counterfactual” exchange rate movement in the absence of intervention by introducing the method of propensity-score matching to estimate the “average treatment effect” (ATE) of intervention. To derive the propensity scores we estimate central bank intervention reaction functions. We estimate the ATE for daily official intervention in Japan over the January 1999–March 2004 period. This sample encompasses a remarkable variation in intervention frequencies as well as unprecedented frequent intervention towards the latter part of the period. We find that only sporadic and relatively infrequent intervention is effective.
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