AI For Sheep Using Frozen-thawed Semen.

End of Project ReportInternational experience has been that cervical insemination of sheep with frozen-thawed semen usually yields unacceptably low pregnancy rates (10 to 30%). An exceptional case has been Norway where non-return rates in on-farm usage are around 60%. The objective of the work described in this report was to develop an AI procedure for Irish conditions, based initially on Norwegian protocols, using semen from individual rams. Such a procedure would greatly facilitate and enhance genetic improvement programmes for sheep. The work undertaken had two separate aspects:- (i) studies on semen, including processing and freezing methods, laboratory evaluation of semen quality post thawing and the relationship of in vitro evaluation to fertilisation rate in vivo (ii) studies on pregnancy rate following AI in relation to issues such as ram breed effects, effects of synchronisation, operator differences and the role of ewe breed inducing the timing of ovulation and various physical and physiological assessments of the cervix at AI. The main results in relation to semen studies were that, while a range of differential staining procedures could be used to objectively evaluate semen with respect to proportion of live speramatozoa and the integrity of sperm cells after thawing, these results were not useful as indicators of fertilisation capacity in vivo. The in vitro fertilisation (IVF) of sheep oocytes recovered from abattoir material gave promising results as a method for evaluating the fertilisation capacity of frozen-thawed semen. The technique requires further validation.Department of Agriculture, Food and the Marin

Effects of old landfills on groundwater quality. Phase 2, investigation of the Thriplow landfill 1996–1997

Disused sand and gravel excavations overlying the major Chalk aquifer at Thriplow in Cambridgeshire have been filled with domestic waste in two phases. One area (Phase 1) was filled between 1957–77 with little compaction of the refuse and was left uncapped, while Phase 2 was deposited between 1981–87 and capped with clay. Aerial photography and surface resistivity surveys indicate that the site geometry is complex, with several phases of landfilling into excavations of differing depths. Drilling through the waste indicates that leachate production and waste stabilisation proceed at different rates in capped and uncapped landfills. Analysis of leachate obtained by centrifugation or squeezing appears to give more insight into the pollution potential than do leach tests with distilled water. The Biological Methane Potential (BMP) of the waste appears to be related to the quantity of decomposable material but the chemical oxygen demand (COD) values are distorted by the presence of reduced metals. Too few boreholes have been drilled to define the leachate source in terms of its spatial distribution and little is known of how its composition has changed with time. However, hydraulic conductivity measurements on the landfill caps suggest that it is sufficiently permeable for all rainfall to potentially infiltrate the waste. Boreholes outside the landfill penetrate the Upper and Lower Chalk, and identify the Melbourn Rock and underlying Plenus Marls at the junction of the two formations about 20 m below ground level (bgl). Surface resistivity surveys using the BGS RESCAN system, confirm aerial photographs of the extent of the landfill and also suggest that leachate has migrated beyond the base of the landfill. Evidence of leachate migration in pre-existing screened boreholes completed above and below the Plenus Marls suggests that leachate is flowing above the Plenus Marls. Hydraulic head measurements whilst drilling a borehole to the base of the lower Chalk approx. 70 m bgl revealed the potential for upward groundwater flow through the Plenus Marls. Thus, previously-drilled boreholes penetrating the Plenus Marls are expected to recharge upwards into the shallow aquifer above the Plenus Marls diluting any leachate in the upper aquifer and distorting the flow regime. Several of these boreholes have subsequently been modified to stem the flow across the Plenus Marls. One borehole down-gradient to the west of the site revealed a large thickness of drift composed of both sand and clay rich material. This suggests the existence of a buried channel, the hydrogeological significance of which has yet to be assessed. Groundwater chemistry appears to be influenced by three major factors. (a) the landfill leachate (b) the composition of shallow groundwater in the top 10 m of the Chalk, and (c) the composition of water from the Lower Chalk. Limited groundwater monitoring data appear to display a cyclic variation in chloride concentration. The origin for this is not clear but it may correlate with cyclic variations in groundwater levels when the water table rises into the waste. Cyclic flushing of the landfill may release leachate into the aquifer giving rise to pulses of chloride. Alternatively changes in chloride may arise by the changing direction of groundwater flow which as yet has not been assessed. A conceptual hydrogeological model in which flow is limited to above the Plenus Marls has been used to develop a more appropriate groundwater flow and solute transport model. However, the model lacks data on aquifer properties, on contaminant inputs concentrations, fluxes and spatial variations, and there is a paucity of monitoring data for calibration. Nonetheless preliminary transport modelling using an equivalent porous medium approach shows that an effective porosity of about 5% best fits the regional data. Since this is much less than the total porosity of about 40% for the Chalk, it would appear that only part of the Chalk is available for flow but that matrix diffusion could play an important role in leachate attenuation. Discrete fracture modelling using the FRACTRAN code has allowed some scoping to be made of the hydraulic properties of the aquifer by comparison with chloride hydrographs, but these again need to be better conditioned by in-situ measurement of fracture distributions and transmissivities. A number of additional activities are required to improve the understanding of flow and contaminant transport at the site. These include better spatial definition of the waste distribution, improved data on the hydraulic properties of the Chalk aquifer, and the use of automatic monitoring to record temporal changes in groundwater chemistry and groundwater levels

Cardiac magnetic resonance stress perfusion imaging for evaluation of patients with chest pain

Background: Stress cardiac magnetic resonance imaging (CMR) has demonstrated excellent diagnostic and prognostic value in single-center studies. Objectives: This study sought to investigate the prognostic value of stress CMR and downstream costs from subsequent cardiac testing in a retrospective multicenter study in the United States. Methods: In this retrospective study, consecutive patients from 13 centers across 11 states who presented with a chest pain syndrome and were referred for stress CMR were followed for a target period of 4 years. The authors associated CMR findings with a primary outcome of cardiovascular death or nonfatal myocardial infarction using competing risk-adjusted regression models and downstream costs of ischemia testing using published Medicare national payment rates. Results: In this study, 2,349 patients (63 ± 11 years of age, 47% female) were followed for a median of 5.4 years. Patients with no ischemia or late gadolinium enhancement (LGE) by CMR, observed in 1,583 patients (67%), experienced low annualized rates of primary outcome (4-fold higher annual primary outcome rate and a >10-fold higher rate of coronary revascularization during the first year after CMR. Patients with ischemia and LGE both negative had low average annual cost spent on ischemia testing across all years of follow-up, and this pattern was similar across the 4 practice environments of the participating centers. Conclusions: In a multicenter U.S. cohort with stable chest pain syndromes, stress CMR performed at experienced centers offers effective cardiac prognostication. Patients without CMR ischemia or LGE experienced a low incidence of cardiac events, little need for coronary revascularization, and low spending on subsequent ischemia testing. (Stress CMR Perfusion Imaging in the United States [SPINS]: A Society for Cardiovascular Resonance Registry Study; NCT03192891)

Guidelines for the management of pregnancy in women with cystic fibrosis

Women with cystic fibrosis (CF) now regularly survive into their reproductive years in good health and wish to have a baby. Many pregnancies have been reported in the literature and it is clear that whilst the outcome for the baby is generally good and some mothers do very well, others find either their CF complicates the pregnancy or is adversely affected by the pregnancy. For some, pregnancy may only become possible after transplantation. Optimal treatment of all aspects of CF needs to be maintained from the preconceptual period until after the baby is born. Clinicians must be prepared to modify their treatment to accommodate the changing physiology during pregnancy and to be aware of changing prescribing before conception, during pregnancy, after birth and during breast feeding. This supplement offers consensus guidelines based on review of the literature and experience of paediatricians, adult and transplant physicians, and nurses, physiotherapists, dietitians, pharmacists and psychologists experienced in CF and anaesthetist and obstetricians with experience of CF pregnancy. It is hoped they will provide practical guidelines helpful to the multidisciplinary CF teams caring for pregnant women with CF

Surgical site infections after emergency hernia repair: substudy from the Management of Acutely Symptomatic Hernia (MASH) study

Introduction Acutely symptomatic abdominal wall and groin hernias (ASH) are a common acute surgical presentation. There are limited data to guide decisions related to surgical repair technique and use of antibiotics, which can be driven by increased risk of surgical site infection (SSI) in this group. This study aims to report rates of SSI following ASH repair and explore the use of patient-reported outcome measure reporting in this setting. Methods An 18-week, UK-based, multicentre prospective cohort study (NCT04197271) recruited adults with ASH. This study reports operatively managed patients. Data on patient characteristics, inpatient management, quality of life, complications, and wound healing (Bluebelle score) were collected. Descriptive analyses were performed to estimate event rates of SSI and regression analysis explored the relationship between Bluebelle scores and SSI. The 30 and 90-day follow-up visits assessed complications and quality of life. Results The MASH study recruited 273 patients, of whom 218 were eligible for this study, 87.2 per cent who underwent open repair. Mesh was used in 123 patients (50.8 per cent). Pre- and postoperative antibiotics were given in 163 (67.4 per cent) and 28 (11.5 per cent) patients respectively. There were 26 reported SSIs (11.9 per cent). Increased BMI, incisional, femoral, and umbilical hernia were associated with higher rates of SSI (P = 0.006). In 238 patients, there was a difference in healthy utility values at 90 days between patients with and without SSI (P = 0.025). Also, when analysing 191 patients with Bluebelle scores, those who developed an SSI had higher Bluebelle values (P < 0.001). Conclusion SSI is frequent in repair of acutely symptomatic hernia and correlates with BMI and site of hernia

The polarized image of a synchrotron-emitting ring of gas orbiting a black hole

High Energy Astrophysic

Constraints on black-hole charges with the 2017 EHT observations of M87*

InstrumentationHigh Energy Astrophysic

The variability of the black hole image in M87 at the dynamical timescale

The black hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable to the 6 day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure-phase measurements on all six linearly independent nontrivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of ∼3°–5°. The only triangles that exhibit substantially higher variability (∼90°–180°) are the ones with baselines that cross the visibility amplitude minima on the u–v plane, as expected from theoretical modeling. We used two sets of general relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas.https://iopscience.iop.org/article/10.3847/1538-4357/ac332e/pdfPublished versio