Titanium and zirconium analyses of quartz and rutile from blueschist samples from the eclogite–blueschist unit (EBU) in northern Sifnos, Greece, have been evaluated to determine the extent to which ...the intersection of the Ti-in-quartz (TitaniQ) and zirconium-in-rutile (ZiR) thermometers reflect peak metamorphic P–T conditions. Ti concentrations range from 100 to 530 ppb and Zr concentrations range from 14 to 44 ppm; there is no significant zoning observed in any grains and no significant differences in concentrations in samples south and north of the Vroulidia shear zone (VSZ). Lines of equal Keq from the TitaniQ and ZiR thermometers intersect at around 450–500 °C and 2.2–2.4 GPa, which is similar to the peak metamorphic conditions of 530 °C, 1.9 GPa for samples north of the VSZ. However, the intersection is inconsistent with the peak metamorphic conditions of 525 °C, 1.1–1.4 GPa for samples south of the VSZ even when TitaniQ temperatures are corrected for reduced activity of TiO
2
. Rather, TitaniQ temperatures are consistent with Ti values being incorporated into quartz during prograde metamorphism along a subduction geotherm of 10–12 deg/km at around 300 °C. ZiR temperatures are consistent with rutile nucleation and growth at around 450–500 °C along a similar metamorphic geotherm after the rutile-in reaction was overstepped by around 1 kJ/mol-O. The TitaniQ and ZiR thermometers do not, therefore, reflect peak metamorphic P–T conditions in these rocks but rather record recrystallization or growth processes during prograde subduction.
An average of 70 samples were collected from 80 dairy farms in England and Wales, from cattle, co-grazed sheep, wildlife and farm wastes, to investigate prevalence, potential sources and transmission ...routes of Cryptosporidium. At least one positive sample was detected on 74 of the farms (92.5%) by IFAT microscopy. The prevalence in cattle was 10.2% (95% CI 9.4–11.1%), with greater prevalences detected in calf samples, especially from those under 1 month (45.1%). Young calves were also more likely to be shedding Cryptosporidium parvum and larger concentrations of oocysts, whereas older calves and adult cattle were more likely to be shedding Cryptosporidium bovis and Cryptosporidium andersoni, respectively. The C. parvum subtypes detected were predominantly from types commonly identified in UK cattle (67% were either IIaA15G2R1 or IIaA17G1R1). A novel subtype, IIaA17G1R2, was identified from one cattle sample.
The prevalence in co-grazed sheep was low (4%). Birds and rodents may represent significant reservoirs of Cryptosporidium due to high prevalence, large oocyst concentrations, and the detection of a C. parvum subtype known to be present in human populations, identified in samples from these wildlife. Cryptosporidium were detected in dirty water and manure, and also from pasture samples where slurry had been spread.
On 64% of the farms, identical Cryptosporidium species were detected (mainly C. parvum or C. bovis) from different cattle groups on the farms, although no direct or indirect contact between the groups were recorded, apart from sharing staff. The same Cryptosporidium species were found in cattle, farm wastes and bird samples on the same farms, but rarely, or not at all, present in sheep or rodent samples. The matching of species/subtypes was also related to the proximity of the different sample sources which may indicate a potential transmission route.
To determine the prevalence and types of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli occurring in pigs at slaughter in the UK in 2013.
Caecal samples from 637 pigs, sampled via a ...UK-wide monitoring programme in 2013, were enriched overnight in buffered peptone water, before plating to CHROMagar CTX and Oxoid Brilliance ESBL agar. Presumptive ESBL-producing E. coli from both media were tested for ESBL phenotype using MAST ESβL ID discs. Isolates with an ESBL phenotype were examined for the presence of blaCTX-M, blaOXA, blaSHV and blaTEM genes using a multiplex PCR. All blaCTX-M and blaSHV genes identified by PCR were sequenced.
A total of 23.4% (95% CI 19.2-27.6) of pigs were positive for ESBL-producing E. coli; 22% (95% CI 17.8-26.1) of the pigs carried E. coli producing CTX-M enzymes comprising enzyme types 1 (18.7% of pigs), 3 (0.2%), 14 (0.5%), 15 (1.4%), 27 (0.5%), 32 (0.5%) and 55 (0.3%) and 2.2% (95% CI 0.8-3.6) of the pigs carried E. coli producing SHV-12. Five pigs carried both CTX-M- and SHV-12-producing E. coli as different isolates. There were no statistically significant differences observed between the two medium types in terms of the proportions of each CTX-M enzyme type isolated.
In this UK study, 23.4% of pigs were found to be positive for ESBL-producing E. coli using selective culture media. The use of two different commercially available ESBL isolation media was found to improve the detection of ESBL-producing E. coli.
New results that employ Zr‐in‐rutile thermometry (ZiR) and quartz‐inclusion‐in‐garnet (QuiG) barometry constrain the P–T conditions of garnet formation in blueschists and eclogites from the island of ...Syros, Greece. QuiG barometry reveals that garnet from different regions across the island formed at pressures ranging from 1.1 to 1.8 GPa and ZiR thermometry on rutile inclusions in garnet constrains the minimum temperature of garnet formation to have been 475–550°C. Most importantly, there is no systematic difference in the conditions of garnet formation from different regions across the island and these results are nearly identical to those obtained from the islands of Sifnos and Ios, Greece. A model is proposed whereby the rocks from all three islands were initially metamorphosed along a relatively shallow geotherm of around 11°C/km to a depth of around 45 km and were then subjected to metamorphism along a geotherm of around 7–8°C/km, which could have been caused by either an increase in the dip of the subduction zone or an increase in the rate of subduction. Garnet formed along this steeper geotherm was accompanied by the release of significant H2O from the breakdown of chlorite over a duration of 1 Ma or less based on thermal and diffusion modeling. It is concluded that rocks from Syros, Sifnos and Ios all followed a similar, roughly counter‐clockwise prograde P–T path and that the present outcrop configuration is largely due to a complex exhumation history.
Plain Language Summary
The metamorphism of rocks in subduction zones releases large quantities of H2O, which ultimately helps flux melting in the overlying mantle leading to explosive island arc volcanism and provides a trigger for large earthquakes. One of the dominant processes that produce large amounts of H2O is the formation of the mineral garnet. Here, we present results that constrain the pressure and temperature conditions for the formation of garnet from three islands in the Greek Cyclades: Syros, Sifnos, and Ios. Our results indicate that garnet formed in different rocks on all three islands in a similar subduction channel along a trajectory where the pressure increase was relatively rapid and the temperature remained nearly constant. The duration of garnet formation in the entire suite of samples is estimated to have occurred in 1 million years or less, during which time significant quantities of fluid are inferred to have been released and which most likely had a major impact on volcanism and seismicity in the region while subduction was active.
Key Points
Blueschist and eclogite assemblages do not necessarily reflect equilibrium crystallization
Exhumation following garnet growth must occur within 1 Ma to preserve compositional zoning
The prograde subduction P–T path in the Cyclades is concave upward with initial shallow subduction followed by near isothermal loading
An abattoir-based study was undertaken between January and May 2013 to estimate the prevalence of Salmonella spp. and Yersinia spp. carriage and seroprevalence of antibodies to Toxoplasma gondii and ...porcine reproductive and respiratory syndrome virus (PRRSv) in UK pigs at slaughter. In total, 626 pigs were sampled at 14 abattoirs that together process 80% of the annual UK pig slaughter throughput. Sampling was weighted by abattoir throughput and sampling dates and pig carcasses were randomly selected. Rectal swabs, blood samples, carcass swabs and the whole caecum, tonsils, heart and tongue were collected. Salmonella spp. was isolated from 30·5% 95% confidence interval (CI) 26·5–34·6 of caecal content samples but only 9·6% (95% CI 7·3–11·9) of carcass swabs, which was significantly lower than in a UK survey in 2006–2007. S. Typhimurium and S. 4,5,12:i:- were the most commonly isolated serovars, followed by S. Derby and S. Bovismorbificans. The prevalence of Yersinia enterocolitica carriage in tonsils was 28·7% (95% CI 24·8–32·7) whereas carcass contamination was much lower at 1·8% (95% CI 0·7–2·8). The seroprevalence of antibodies to Toxoplasma gondii and PRRSv was 7·4% (95% CI 5·3–9·5) and 58·3% (95% CI 53·1–63·4), respectively. This study provides a comparison to previous abattoir-based prevalence surveys for Salmonella and Yersinia, and the first UK-wide seroprevalence estimates for antibodies to Toxoplasma and PRRSv in pigs at slaughter.
Gastrointestinal stromal tumors (GIST) are rare tumors of the gastrointestinal (GI) tract that arise from primitive mesenchymal cells. GISTs occur throughout the GI tract but are usually located in ...the stomach and small intestine. The majority of GISTs are immunohistochemically positive for c-kit protein (CD 117) and CD34. GISTs express a heterogeneous clinical course not easily predicted by standard pathological means. The most important prognostic factors are size > 5 cm, tumor necrosis, infiltration and metastasis to other sites, mitotic count > 1-5 per 10 high-powered fields, and most recently, mutation in the c-kit gene. Surgical resection remains the mainstay of treatment, as chemotherapy and radiation are ineffective. Long-term follow-up is imperative, as recurrence rates are high.
Between 2005 and 2007, E. coli obtained from clinical diagnostic submissions from cattle, goats, pigs and sheep to government laboratories in England and Wales were tested for sensitivity to 16 ...antimicrobials. Resistance was most commonly observed against ampicillin, streptomycin, sulphonamides and tetracyclines. Resistance levels varied significantly between species, with isolates from cattle frequently showing the highest levels. Verocytotoxigenic E. coli (VTEC) expressed less resistance than non-VTEC. Only 19·3% of non-VTEC and 43·5% of VTEC were susceptible to all antimicrobials, while 47·1% and 30·4%, respectively, were resistant to ⩾5 antimicrobials. The resistance phenotype SSuT was commonly observed, and isolates resistant to third-generation cephalosporins were also identified. We recommend judicious antimicrobial usage in the livestock industry in order to preserve efficacy.
Salmonella prevalence in UK pigs is amongst the highest in Europe, highlighting the need to investigate pig farms which have managed to maintain a low Salmonella seroprevalence. A total of 19 pig ...farms that had a consistently low (<10%) seroprevalence over 4 years (named Platinum farms) were compared against 38 randomly selected Control farms, chosen to match the same distribution of production types and geographical distribution of the Platinum farms. Each farm was visited and floor faeces and environmental samples were collected. It was shown that Control farms had a significantly higher median percentage of pooled faecal samples positive for Salmonella compared with the Platinum farms (12.1% and 0.4% for pooled faecal samples, respectively) and were more likely to have serovars of public health importance detected (S. Typhimurium/ monophasic variants or S. Enteritidis). Considering the comprehensive on-farm sampling, the identification of farms negative for Salmonella, along with the identification of those that had maintained low prevalence over a long period is important. The risk factor analyses identified pelleted feed, feed deliveries crossing farm perimeter and regular antibiotic use as associated with being a Control farm. Performance data indicated that Platinum farms were performing better for slaughter live weight than Controls. Limited assessments of available pig movement records suggested that the source of pigs was not key to Platinum status, but further study would be needed to confirm this finding. These results emphasise that maintaining very low prevalence on UK farms is achievable.
This study investigated the potential spread of CTX-M-14 Escherichia coli from a known ESBL E. coli positive farm and risk factors for the presence of CTX-M E. coli on dairy farms. Between November ...2009 and March 2010, 65 farms in North West England and North Wales were visited and animals sampled for E. coli producing CTX-M ESBLs. Seventeen of these were known to have received animals from a known ESBL E. coli positive ‘index’ farm since 2005 (linked farms). The prevalence of CTX-M E. coli in the population of linked farms was 58.8% (10/17; CI95% 32.9–81.6%) and in the randomly selected control population was 35.4% (17/48; CI95% 22.2–50.5%). There was no significant (p>0.05) linkage for the detection of any CTX-M E. coli or specifically a CTX-M-14 E. coli to the index farm. Group 1 (CTX-M-15, CTX-M-55, CTX-M-1, CTX-M-32), group 2 (CTX-M-2) and group 9 (CTX-M-14, CTX-M-14B, CTX-M-27) CTX-M E. coli were identified on the study farms. Molecular analysis revealed that three plasmids from linked farms had similar sizes (95kbp), replicon type (IncK) and backbone genes as that from the index farm. Logistic regression analysis revealed that farms that had used a 3rd or 4th generation cephalosporin (ceftiofur, cefoperazone and cefquinome) in livestock in the last 12months were nearly 4times more likely to have ESBL E. coli present (p=0.037; OR=3.93). There was no significant association between presence of CTX-M E. coli and the use of any 1st or 2nd generation cephalosporins. Several other risk factors for the presence of CTX-M E. coli were identified, such as storage of slurry in a pit, operating an open herd policy and infrequent cleaning of calf feeding equipment.
The occurrence of glaucophane-bearing marbles on Syros is noteworthy because reports of marbles that contain glaucophane are rare among descriptions of high-pressure marbles. On Syros, the marbles ...are composed primarily of calcite with or without dolomite and quartz. Much of the calcite in these marbles shows oriented columnar structures that are interpreted as pseudomorphs of prismatic aragonite. The columnar structure is particularly well developed in layers of pure CaCO3 and is one indicator of the high-pressure history of these marbles. Metamorphosed admixtures of carbonate and mafic silicate material yielded minerals that are typical for eclogite facies and blueschist facies. These impure marbles are widespread and contain assemblages of various combinations of glaucophane/ferroglaucophane, Na-pyroxene (omphacite to jadeite), epidote, garnet, paragonite and phengitic white mica. Based on calculated mineral equilibria, the assemblages and mineral compositions in the marbles and associated rocks place narrow constraints on the metamorphic P–T path and the grain-boundary fluid composition of the marbles. The occurrence of glaucophane + CaCO3 + dolomite + quartz suggests that the P–T trajectory that was followed by the rocks crossed a reaction such as albite/Na-pyroxene +dolomite + quartz → glaucophane + CaCO3, but did not exceed the P–T stability of the reaction dolomite + quartz → tremolite + CaCO3. The P–T locations of these reactions are sensitive to fluid composition and indicate that the attending fluid phase was water-rich with XCO2 constrained to be < 0·03; a value of XCO2 of 0·01 best fits the observed assemblages. Relict lawsonite + Al-rich epidote in schists associated with the glaucophane marbles also has a T–XCO2 stability that is limited to fluids with XCO2 < 0·03. This observation suggests that the grain-boundary fluid of the whole subduction package of schist, blueschist and marble was rich in H2O over most of its metamorphic history. The P–T–XCO2 stability of assemblages common in the schist and marble constrains the P and T maxima for these rocks to about 500°C and 15–16 kbar. These P–T constraints, together with the tectonic fabric of the marbles, suggest that deformation and recrystallization occurred at or near the thermal maximum of metamorphism.
PDF
