Telychian to Sheinwoodian (Silurian) rocks of the Midland Platform and the adjacent shelf (UK) document the onlap and transgression of an irregular unconformity surface by a shallow sea. Integrated borehole and outcrop studies have allowed for the development of a sequence stratigraphic model and a eustatic sea-level curve, the magnitude of which has been scaled using rocky shorelines and changes in benthic assemblages and facies minus the effects of subsidence. Notwithstanding uncertainties in the datasets used, the timing of transgressions and regressions matches globally identified sea-level changes, and both the durations of sea-level change and their magnitudes are indicative of glacio-eustasy. Our long-term sea-level curve identifies a rise in sea-level from middle to late Telychian times, followed by a fall, which culminates in a middle Sheinwoodian sea-level low. Both the timing and magnitude of sea-level changes match contemporaneous climate variations, and these indicate an early to mid-Telychian warming trend followed by late Telychian cooling, which peaks in the middle Sheinwoodian. Notably, the overall magnitude of the long-term regression associated with the late Telychian to middle Sheinwoodian is comparable with that reported from the end-Ordovician glaciation, but probably reflects a more protracted episode of cooling, ice sheet growth and sea-level fall.

The globally-recognised Homerian (Silurian) carbon isotope excursion (CIE) occurs in the Much Wenlock Limestone Formation and Gorsley Limestone of the May Hill and Gorsley inliers of the southern part of the Midland Platform (eastern Avalonia), England. This CIE is associated with eustatic sea-level fluctuations and time-specific facies, and is documented in limestone facies formed in a tropical shallow marine setting, that crop out at the key localities of Hobbs Quarry, Hobbs Lane, and Linton Quarry. Carbon isotope trends and values from these localities identify the falling limbs of the first and second peaks of the Homerian CIE at Hobbs Quarry and Hobbs Lane, respectively, and the low between these peaks at Linton Quarry. The identification and correlation of these parts of the Homerian CIE, alongside the correlation of lithofacies, bentonites and sea-level changes, indicate that at May Hill, the Much Wenlock Limestone Formation began near the top of Silurian stage slice Ho1 and ended near the top of Ho3 (i.e. middle to end Homerian), as is the case for the inner part of the Midland Platform to the north of the study area. Lithofacies of the Gorsley Limestone (Gorsley Inlier), alongside carbon isotope values, correlate to the middle of the Much Wenlock Limestone Formation, as developed at May Hill and across the inner part of the Midland Platform. This indicates that the unconformity at the top of the Gorsley Limestone omits the latest Homerian limestones and second peak of the Homerian CIE, as well as the overlying Gorstian. Furthermore, the uplift, subaerial exposure, and weathering of pyrite-rich sediments in the Gorsley area, to form the Gorsley High, may have supplied iron into the surrounding marine environment, and resulted in the localised development of the latest Homerian ferruginous crinoidal grainstones of the neighbouring May Hill Inlier and Ledbury Hills. These results demonstrate that the CIE and associated strata in the study sites are consistent with regional trends, and therefore add to the global database of these mid-Silurian stratigraphic changes.

The Silurian Coralliferous Formation of Pembrokeshire comprises 94–143 m of shelfal sediments deposited on the southern margin of the Welsh Basin, UK. The succession begins with rudites (Renney Slip Member), which are overlain by interbedded silty mudstone and sandstone (Deadman's Bay Member). Biostratigraphical control is weak between the two principal sections (Renney Slip and Marloes Sands), but high-resolution chemostratigraphy permits 11 subdivisions to be distinguished. Some chemostratigraphical units can be traced between the sections, whereas others are locally absent. The correlation of the chemostratigraphical units has been compared with sea-level cycles identified by a study of the frequency, distribution and characteristics of storm-beds using proximality trend analysis. This suggests a synchroneity of traceable chemostratigraphical units within the Deadman's Bay Member, indicating that deposition began in the Renney Slip Section, and that a greater water depth was achieved there. A holistic assessment shows that the Coralliferous Formation onlaps an unconformity surface with a palaeo-relief of 57 m, over a current distance of 3 km. Further considerations of benthic assemblages, subsidence rates and global sea-level fluctuations support the presence of a late Telychian transgression with glacio-eustasy contributing between 40 and 70 m to that sea-level rise.

BACKGROUND:Osteoarthritis of the knee is a major cause of disability worldwide. Non-operative treatments can reduce the morbidity but adherence is poor. We hypothesised that adherence could be optimised if behavioural change was established in the preoperative period. Therefore, we aimed to assess feasibility, acceptability, and recruitment and retention rates of a preoperative package of non-operative care in patients awaiting knee replacement surgery. METHODS:We did an open-label, randomised controlled, feasibility trial in two secondary care centres in the UK. Eligible participants were aged 15-85 years, on the waiting list for a knee arthroplasty for osteoarthritis, and met at least one of the thresholds for one of the four components of the preoperative package of non-operative care intervention (ie, weight loss, exercise therapy, use of insoles, and analgesia adjustment). Participants were randomly assigned (2:1) to either the intervention group or the standard of care (ie, control) group. All four aspects of the intervention were delivered weekly over 12 weeks. Participants in the intervention group were reviewed regularly to assess adherence. The primary outcome was acceptability and feasibility of delivering the intervention, as measured by recruitment rate, retention rate at follow-up review after planned surgery, health-related quality of life, joint-specific scores, and adherence (weight change and qualitative interviews). This study is registered with ISRCTN, ISRCTN96684272. FINDINGS:Between Sept 3 2018, and Aug 30, 2019, we screened 233 patients, of whom 163 (73%) were excluded and 60 (27%) were randomly assigned to either the intervention group (n=40) or the control group (n=20). 34 (57%) of 60 participants were women, 26 (43%) were men, and the mean age was 66·8 years (SD 8·6). Uptake of the specific intervention components varied: 31 (78%) of 40 had exercise therapy, 28 (70%) weight loss, 22 (55%) analgesia adjustment, and insoles (18 [45%]). Overall median adherence was 94% (IQR 79·5-100). At the final review, the intervention group lost a mean of 11·2 kg (SD 5·6) compared with 1·3 kg (3·8) in the control group (estimated difference -9·8 kg [95% CI -13·4 to -6·3]). A clinically significant improvement in health-related quality o life (mean change 0·078 [SD 0·195]) were reported, and joint-specific scores showed greater improvement in the intervention group than in the control group. No adverse events attributable to the intervention occurred. INTERPRETATION:Participants adhered well to the non-operative interventions and their health-related quality of life improved. Participant and health professional feedback were extremely positive. These findings support progression to a full-scale effectiveness trial. FUNDING:Versus Arthritis.

Quarries between Old Radnor and Presteigne, Welsh Borderlands, expose a Silurian nearshore succession, which onlaps a rocky palaeotopography of the Neoproterozoic basement that had been uplifted along the Church Stretton Fault Zone. The succession documents the Aeronian to Sheinwoodian transgression of an island or islands, with the following sequence of events: deposition of shallow marine sandstones (Folly Sandstone Formation), regional uplift, preservation of a rocky shoreline and associated deposits (Dolyhir Rudite Member), deposition of limestones characterized by a profusion of coralline algae and the abundant remains of reefs (Dolyhir and Nash Scar Limestone Formation), and finally deposition of trilobitic silty mudstones (basal Coalbrookdale Formation). Facies analysis, carbon isotope (δ13Ccarb) values, sequence stratigraphy, and collections of bryozoans, conodonts, thelodonts, and trilobites have been used here as a means of refining our stratigraphic understanding of this unique succession. The revised stratigraphy demonstrates many similarities with the adjoining Midland Platform and the wider Silurian world. Notable features include the globally recognized early Sheinwoodian carbon isotope excursion and sea-level changes of regional and global extent. As one of the best examples of its kind, the palaeoshoreline and nearshore succession of Old Radnor and Presteigne acts as a depositional model for ancient rocky shores worldwide.

We convened a multidisciplinary Working Party on behalf of the Association of Anaesthetists to update the 2011 guidance on the peri-operative management of people with hip fracture. Importantly, these guidelines describe the core aims and principles of peri-operative management, recommending greater standardisation of anaesthetic practice as a component of multidisciplinary care. Although much of the 2011 guidance remains applicable to contemporary practice, new evidence and consensus inform the additional recommendations made in this document. Specific changes to the 2011 guidance relate to analgesia, medicolegal practice, risk assessment, bone cement implantation syndrome and regional review networks. Areas of controversy remain, and we discuss these in further detail, relating to the mode of anaesthesia, surgical delay, blood management and transfusion thresholds, echocardiography, anticoagulant and antiplatelet management and postoperative discharge destination. Finally, these guidelines provide links to supplemental online material that can be used at readers' institutions, key references and UK national guidance about the peri-operative care of people with hip and periprosthetic fractures during the COVID-19 pandemic.

The origin of moderate magnitude (tens of metres), short-term Cretaceous eustatic cycles remains enigmatic. The historical view of ubiquitous Cretaceous warmth casts doubt on the presence of significant terrestrial ice caps and the role of glacio-eustasy. As such, aquifer-eustasy is increasingly advocated as the primary driver of Cretaceous short-term sea-level change. Here, we analyse the role of aquifereustasy in driving Cretaceous short-term cycles by assessing the spatio-temporal pattern of aridity and humidity under differing CO2 forcing in new climate simulations for the Valanginian, Turonian, and Maastrichtian. Elevated CO2 forcing acts to increase the spatial extent of fully arid land areas, while resulting in only a marginal expansion of fully humid zones. Consequently, the greatest aquifer charge is more likely during lower CO2/cooler intervals, indicating that aquifer-eustasy works in phase with both glacio- and thermo-eustasy in contrast to the current aquifer-eustasy paradigm. Modern data indicate that climate is a primary control on water table depth. Using this constraint, the hydrological response in our Cretaceous simulations to large changes in atmospheric CO2 are insufficient to generate reported eustatic magnitudes. Our most likely aquifer-eustasy estimates are decimetre scale. Even using optimistic values for the impact of lakes and assuming the water table depth was reduced from the modern average to 0 m globally, the total aquifer-eustasy response remains smaller than 5 m. Our results indicate that glacio-eustasy was the most likely driver of Cretaceous short-term cycles, consistent with a growing body of evidence that challenges the ubiquitously warm Cretaceous notion. (C) 2020 Elsevier Ltd. All rights reserved.

AbstractNew δ13Ccarb and microfacies data from Hereford–Worcestershire and the West Midlands allow for a detailed examination of variations in the Homerian carbon isotope excursion (Silurian) and depositional environment within the Much Wenlock Limestone Formation of the Midland Platform (Avalonia), UK. These comparisons have been aided by a detailed sequence-stratigraphic and bentonite correlation framework. Microfacies analysis has identified regional differences in relative sea-level change and indicates an overall shallowing of the carbonate platform interior from Hereford–Worcestershire to the West Midlands. Based upon the maximum δ13Ccarb values for the lower and upper peaks of the Homerian carbon isotope excursion (CIE), the shallower depositional setting of the West Midlands is associated with values that are 0.7 ‰ and 0.8 ‰ higher than in Hereford–Worcestershire. At the scale of parasequences the effect of depositional environment upon δ13Ccarb values can also be observed, with a conspicuous offset in the position of the trough in δ13Ccarb values between the peaks of the Homerian CIE. This offset can be accounted for by differences in relative sea-level change and carbonate production rates. While such differences complicate the use of CIEs as a means of high-resolution correlation, and caution against correlations based purely upon the isotopic signature, it is clear that a careful analysis of the depositional environment can account for such differences and thereby improve the use of carbon isotopic curves as a means of correlation.

No consensus currently exists regarding the magnitude of Cretaceous short-term (less than 3 Ma in duration) eustatic sea-level change. The lack of a consensus limits the ability to predict sedimentary facies and architecture and to assess the potential drivers of eustasy during a period of Earth history considered as significantly warmer than today. Consequently, this review documents, weighs, synthesises, and summarises records of short-term relative sea-level change and evaluates the observed trends in magnitude within the context of potential climatic drivers and their eustatic expression. Although Cretaceous sea-level change is addressed in many publications, estimates of absolute values are relatively limited, often cover short time intervals, and use different methods. Based upon integrated geological and statistical analyses, four broad episodes of magnitude change have been identified. Three of these episodes reflect trends of increasing magnitudes of sea-level change from the Berriasian to early Hauterivian, late Hauterivian to Aptian, and Santonian to Maastrichtian. The fourth episode reflects a decreasing magnitude trend from the Albian to Coniacian. In addition, the maximum magnitude of sea-level change, at an approximate stage level, has been identified and categorised as slight (less than 10 m), modest (10 to 40 m), or significant (41 to 65 m). Significant magnitudes are inferred for the Valanginian, Aptian, Albian, and Maastrichtian; exclusively slight magnitudes are restricted to the Berriasian. Such an assessment casts doubt on the repeated and stratigraphically widespread episodes of very large magnitudes (more than 75 m) advocated by some workers, and instead defines distinct periods and magnitudes of sea-level change that should be globally reflected in sedimentary facies patterns. For example, intervals of sea-level fall of significant magnitude are commonly associated with the increased delivery of sediment into basinal settings, including the marked progradation of shallow-marine sediments, whilst up-systems tract there can be enhanced development of karst and erosional features. Because climatically driven eustasy is the likely cause of short-term sea-level change, an assessment of the characteristic maximum magnitude limits of the principal climatic drivers (thermo-, aquifer-, and glacio-eustasy) has been made. Such a comparison argues for glacio-eustasy as the driver of significant short-term sea-level change. In addition, climate proxy data demonstrates that the Valanginian, Aptian, Albian, and Maastrichtian are intervals of cooling within the Cretaceous, thereby supporting the link between significant magnitudes and glacio-eustasy.

Fossil abundance and diversity in geological successions are subject to bias arising from shifting depositional and diagenetic environments, resulting in variable rates of fossil accumulation and preservation. In simulations, this bias can be constrained based on sequence‐stratigraphic architecture. Nonetheless, a practical quantitative method of incorporating the contribution of sequence‐stratigraphic architecture in community palaeoecology and diversity analyses derived from individual successions is missing. As a model of faunal turnover affected by the stratigraphic bias, we use the ‘Mulde event’, a postulated mid‐Silurian interval of elevated conodont turnover, which coincides with global eustatic sea‐level changes and which has been based on regionally constrained observations. We test whether conodont turnover is highest at the boundary corresponding to the ‘event’ and post‐‘event’ interval against the alternative that conodont turnover reflects habitat tracking and peaks at facies shifts. Based on the previously documented, parasequence‐level stratigraphic framework of sections in the northern and central part of the Midland Platform, the relative controls of sequence‐stratigraphic architecture, time and depositional environment over conodont distribution are evaluated using permutational multivariate analysis of variance. The depositional environment controls the largest part of variability in conodont assemblage composition, whereas the postulated ‘Mulde event’, or genuine temporal change in conodont diversity, cannot be detected. Depending on the binning of the stratigraphic succession, contrasting diversity and turnover patterns can be produced. The simple approach proposed here, emulating partitioning of β diversity into spatial and temporal components, may help to constrain the stratigraphic bias, even at the scale of an individual section.

Abstract New δ13Ccarb data from the most stratigraphically extensive graptolitic sections of Homerian age in the study area are reported from Wenlock Edge and the Ludlow Anticline (UK). These sections, situated upon the Midland Platform (Avalonia), were key in establishing the Homerian graptolite biozonation used within the type Wenlock Series, and are consequently of international importance. Based upon 162 δ13Ccarb samples from four outcrops (Eaton Track, Longville–Stanway Road Cutting, Burrington Section and Mortimer Forest Stop 1), new graptolite collections and a re-evaluation of the original graptolite collections, the onset of both lower (older) and upper (younger) peaks of the Homerian Carbon Isotope Excursion have been calibrated to a revised graptolite biozonation (lundgreni – nassa – praedeubeli-deubeli – ludensis biozones). In addition, high-resolution correlation between the Ludlow Anticline and Wenlock Edge has been achieved by bio-, chemo- and sequence stratigraphic techniques. These correlations suggest a uniformity of depositional rates across the study area and indicate minor diachroneity at the base of the Much Wenlock Limestone Formation. Finally, correlations of the Midland Platform Homerian Carbon Isotope Excursion have allowed for better comparisons with other sections from which high-resolution graptolite and carbon isotope data are available. Such comparisons highlight the pan-regional synchronicity of the Homerian Carbon Isotope Excursion.

The late Wenlock is characterized by two global regressive-transgressive eustatic cycles in association with a double-peaked positive carbon isotope excursion. The onset of the excursion coincides with an extinction event affecting graptolites (the lundgreni event) and proposed to affect conodonts (the Mulde Event) and proliferation of non-skeletal carbonates. In order to test the hypothesized relationships between eustatic and ecological changes, the tropical carbonate Homerian succession in Podolia has been examined with respect to conodont, sequence and C-13 stratigraphy. Four depositional sequences (DS) have been identified. The onset of the C-13 excursion occurs at the boundary between DS1 and DS2, corresponding to a forced regression of proposed glacioeustatic origin. The following rapid eustatic transgression associated with the highest C-13 values of 5.2 parts per thousand includes a higher-order shallowing episode recorded in Podolia as normal regression and a boundary between DS2 and DS3. This interval is distinguished by the presence of oncoids and thrombolitic buildups. The latest Wenlock eustatic fall and the corresponding second peak of the C-13 excursion corresponds in Podolia to a stratigraphic gap. The first C-13 peak (top of DS1 and DS2) corresponds to the O.bohemica longa conodont Zone, the interval between the two peaks (DS3) - to K.ortus absidata and C.murchisoni zones, and DS4 is tentatively placed in the lowermost Ludlow Series. The record of relative sea-level changes in Podolia is consistent with reconstructions based on successions in England and Sweden. The moderate drop in conodont taxonomic richness may reflect the primary depositional control over their proposed extinction.

The Wenlock–Ludlow series boundary (Silurian) has been recognized as a time of pronounced sea-level rise and the end of a globally recognized Late Homerian Stage (Mulde) positive carbon isotope excursion (CIE). However, the precise timing and synchronicity of the end of the excursion with respect to the Wenlock–Ludlow boundary is debated. Within the type Wenlock and Ludlow areas (UK), high-resolution δ13Ccarb isotope data are presented across the Wenlock–Ludlow boundary, and within a range of carbonate platform settings. Correlation between sections and depositional settings has been based upon the characteristics of high-order sea-level fluctuations (parasequences). Comparisons between parasequence-bounded δ13Ccarb values reveal clear spatial variations, with lighter values recorded from more distal settings and heavier values from shallower settings. Temporal variations in the δ13Ccarb values are also documented and appear to reflect local variations in carbonate provenance and productivity in response to sea-level rise. While δ13Ccarb values converge in all sections towards the Wenlock–Ludlow boundary, the apparent end of the Mulde CIE appears diachronous and is progressively older within more distal settings.

New high resolution δ13Ccarb isotope data are presented through the Sheinwoodian and lower Homerian stages of the Wenlock Series (Silurian) from sections in Shropshire, Herefordshire and the West Midlands (UK). This data identifies the well-known Early Sheinwoodian positive Carbon Isotope Excursion (ESCIE), the minor mid-ESCIE negative shift, and an Early Homerian positive Carbon Isotope Excursion (EHCIE) in the region of 1.4‰, as developed upon the Midland Platform and in close proximity to the Sheinwoodian and Homerian GSSPs. These carbon isotope excursions have been correlated against graptolite, conodont and chitinozoan frameworks from across the Midland Platform, and alongside details of sedimentology and faunas, have allowed for the establishment of a sequence stratigraphic framework. These integrated data sets reveal that the shallow-water Barr–Buildwas–Woolhope limestones reflect approximately synchronous deposition across the Midland Platform; in that they all contain the ESCIE and five widely traceable depositional cycles. Moreover, biostratigraphic and sequence stratigraphic frameworks from across the Midland Platform (Avalonia) confirm that both the ESCIE and the five cycles are synchronous with records from other palaeocontinents (Baltica and Laurentia) and indicate that the early Sheinwoodian graptolite zones as established in the type area are in need of review.

C-13(carb) data from the Tortworth and Woolhope inliers, Midland Platform, UK, provide a record of part of the early Sheinwoodian (Ireviken) carbon isotope excursion. The shallow-marine mixed carbonate/siliciclastic successions exhibit a maximum C-13(carb) value of +5.8 parts per thousand VPDB. Values begin to increase sharply at the Pycnactis Band, a prominent flooding surface, and decrease over a transgressive sequence between the Woolhope and Coalbrookdale formations. The study provides an improved chronostratigraphic correlation across the Sheinwoodian of the Midland Platform (Avalonia) and further afield, and highlights the power of integrated chemostratigraphy and sequence stratigraphy in the absence of well-developed biostratigraphy.

A microbial origin has been proposed for matrix-supported, low-diversity buildups reported from different palaeocontinents during the onset of the Mulde positive carbon isotope excursion. We have investigated a small aphanitic buildup from the Lower Quarried Limestone Member of the Much Wenlock Limestone Formation, exposed at Whitman's Hill (Herefordshire), corresponding to the central part of the Midland Platform (UK). Up to 50% of the rock volume in this buildup consists of mottled micrite. The SEM studies revealed that the micrite is largely detrital and does not show features characteristic of calcareous cyanobacteria or leiolites. The aphanitic character of the buildup is suggested to be controlled by the depositional rate, and the widespread occurrence of matrix-supported reefs in this interval to be driven by a mid-Homerian rapid eustatic transgression.

The Late Wenlock Series (Homerian Stage) of the central Midland Platform occupies an area stretching from Ledbury to the Malvern, Suckley and Abberley Hills. Based upon the establishment of a sequence stratigraphic framework for the Much Wenlock Limestone Formation, and the immediately under- and over-lying Coalbrookdale and Lower Elton Formations, comparisons can now be made with key sections across the northern Midland Platform and beyond. These correlations have been strengthened by the determination of apatite rare earth element (REE) geochemical signatures obtained from four volcanic ash layers (bentonites) at Whitman's Hill Quarry (Herefordshire), which allow for comparisons with published coeval sections at Wren's Nest Hill (West Midlands) and Wenlock Edge (Shropshire), as well as with bentonites described from the Island of Gotland (Sweden).Across the study area fifteen parasequences associated with two pronounced regressive episodes, separated by a marked transgression, can be identified. The lithological responses to these relative sea-level changes are the same as those reported from the West Midlands, including the threefold division of the Much Wenlock Limestone Formation into Lower Quarried Limestone, Nodular Beds and Upper Quarried Limestone Members. Apatite REE geochemical signatures from Whitman's Hill Quarry identify three bentonites which probably originated from a granodiorite magmatic source, while a fourth bentonite has a distinctively mafic composition, more akin to that of a gabbro or syenite. This distinctively mafic bentonite is preserved on a marked flooding surface within the Nodular Beds Member and appears compositionally and stratigraphically equivalent to a bentonite at Wren's Nest Hill (West Midlands). Furthermore in both sections this bentonite is of notable thickness (120-200 mm) allowing for its identification in other sections across the region. Comparisons with Gotland identify three closely spaced bentonites of a similar mafic composition to the bentonite described from the Midland Platform. While similarities in stratigraphic position and composition do not, at present, allow for the identification of a single ash fall event covering both the Midland Platform and Gotland, they are indicative of a shared source region, which may offer the possibility for future bentonite correlation between these regions. (C) 2013 Elsevier B.V. All rights reserved.

High-precision isotope-dilution U-Pb (zircon) dating was conducted on three volcanic ash fall (bentonite) samples from the Swedish island of Gotland, and on a fourth bentonite from the West Midlands, England. Zircons from the Ireviken, Grotlingbo, Djupvik (Gotland), and Wren's Nest Hill-15 (West Midlands) bentonites yielded weighted mean Pb-206/U-238 ages of 431.83 +/- 0.23/0.67 Ma, 428.45 +/- 035/0.73 Ma, 428.06 +/- 0.2110.66 Ma, and 427.86 +/- 032/0.71 Ma, respectively (analytical/total uncertainties). These biostratigraphically well-controlled age dates effectively bracket the Wenlock Epoch of the Silurian Period and provide control for the duration of one of the major Paleozoic biotic events and associated perturbations to the global carbon cycle (the "Big Crisis" or lundgreni event- graptolites; the NIulde Event-conodonts; the Mulde excursion-carbon isotopes). These new data suggest an older and shorter duration for the recalibration of the Wenlock Series and demonstrate that the cascade of biological and chemical events that took place during the Big Crisis happened on time scales of tens to hundreds of thousands of years.