79 research outputs found
South Wales
Carboniferous rocks in this region occur in a broadly east-west trending syncline, the
core of which includes the South Wales and Pembrokeshire coalfields (Fig. 5.1).
Tournaisian and Visean strata (Avon and Pembroke Limestone groups) represent
deposition on a southward prograding carbonate ramp evolving into a carbonate shelf
(Wright 1987), in a succession which shows similarities to that of the Bristol and
Mendips areas (Chapter 6). The main outcrops, in south Pembrokeshire, Gower and
the Vale of Glamorgan, occur along the southern periphery of the coalfields and are
commonly affected by Variscan thrusting and folding. Thinner successions occur
along what is termed the East Crop and North Crop of the South Wales Coalfield,
where much of the Visean succession is absent due to sub-Namurian and intra-Visean
unconformities. Namurian fluvio-deltaic deposits (Marros Group) flank the South
Wales and Pembrokeshire coalfields. Much of the lower and middle Namurian
succession is absent across the region, except in the west of the South Wales Coalfield
where only small parts are absent beneath an intra-Namurian unconformity.
Westphalian fluvio-lacustrine deposits (South Wales Coal Measures Group) form the
South Wales and Pembrokeshire coalfields, located to the east and west of
Carmarthen Bay, respectively. Westphalian to Stephanian Pennant alluvial facies
(Warwickshire Group) occur in the core of the South Wales Coalfield syncline.
Deposition of the South Wales Coal Measures and Warwickshire groups was
probably laterally contiguous with those in the Bristol and Somerset coalfields
(Chapter 6), but the Usk-Cowbridge High controlled and restricted sedimentation for
much of the Carboniferous, with pre-Namurian uplift and erosion removing the
Tournaisian and Visean succession. Later uplift is also believed to have caused
attenuation of the Warwickshire Group in the east of the South Wales Coalfield. The
lithostratigraphical nomenclature for the region is that of Waters et al. (2007; 2009)
Lithostratigraphy of the Old Red Sandstone successions of the Anglo-Welsh Basin
This report presents a revised lithostratigraphy of the Old Red Sandstone of the Anglo-Welsh Basin, prepared under the auspices of the British Geological Survey (BGS) Stratigraphical Framework Committee (SFC). The report provides a correlation of the successions in different parts of the basin and rationalises group and formation nomenclature for the outcrops of Old Red Sandstone in England and Wales. It is based on a previous discussion document (Barclay, unpublished MS, 2007) which presented options in a three-step approach towards rationalisation to a proposed single, standard scheme that can be applied to most of the Pridoli–Lochkovian succession (lower part of the Lower Old Red Sandstone) of the Anglo-Welsh Basin.
The earlier discussion document was circulated among geologists with expertise in the Old Red Sandstone of the Anglo-Welsh Basin in and outside the British Geological Survey. This version takes account of the suggestions for improvement and comments made during the consultation process. One significant change from previous classifications concerns the base of the Old Red Sandstone. There is a consensus that this should be placed at the base of the first major incoming of red- or green-bed (‘Old Red Sandstone’) terrestrial facies, thereby excluding the shallow marine Downton Castle Sandstone and Tilestones formations that have traditionally been included in the Old Red Sandstone. The report proposes the introduction of two new names and group status for the successions traditionally referred to as the Lower Old Red Sandstone and Upper Old Red Sandstone. The two successions are separated by the major, regional, cleavage-forming Acadian unconformity, and because of this, the authors have made a case for giving them supergroup status. However, they are here accorded group status in accordance with practice in the other Old Red Sandstone basins of the United Kingdom, both onshore and offshore. In nationwide standardisation, all the groups are informally referred to the as-yet undefined parent ‘Old Red Sandstone Supergroup’, although the authors propose that the term ‘Old Red Sandstone’ is best retained as a facies (or magnafacies) term. The Lower Old Red Sandstone is termed the Daugleddau Group and the Upper Old Red Sandstone is termed the Brecon Beacons Group
A geological basis for land-use planning: Garforth-Castleford-Pontefract : 1:10000 sheets SE42NW, NE, SW, SE, SE43SW and SE52SW, parts of 1:50000 geological sheets 70 (Leeds) and 78 (Wakefield)
This report describes a stuodfy t he Garforth- Castleford
- Pontefract areac ommissioned by the Departmenot of the
Environment and jointly funded by the Department and
the British Geological Survey.
The aims of the study were to compile and collate a geological database, and to present threes ults in terms of
their application to land use planning and development as
a foundation for:
a. land-use planning for development and
b. safeguarding of mineral resources, and
c. effective future geological researc
Enhanced magnetocaloric effect in frustrated magnets
The magnetothermodynamics of strongly frustrated classical Heisenberg
antiferromagnets on kagome, garnet, and pyrochlore lattices is examined. The
field induced adiabatic temperature change (dT/dH)_S is significantly larger
for such systems compared to ordinary non-frustrated magnets and also exceeds
the cooling rate of an ideal paramagnet in a wide range of fields. An
enhancement of the magnetocaloric effect is related to presence of a
macroscopic number of soft modes in frustrated magnets below the saturation
field. Theoretical predictions are confirmed with extensive Monte Carlo
simulations.Comment: 7 page
Noise Sources in Photometry and Radial Velocities
The quest for Earth-like, extrasolar planets (exoplanets), especially those
located inside the habitable zone of their host stars, requires techniques
sensitive enough to detect the faint signals produced by those planets. The
radial velocity (RV) and photometric transit methods are the most widely used
and also the most efficient methods for detecting and characterizing
exoplanets. However, presence of astrophysical "noise" makes it difficult to
detect and accurately characterize exoplanets. It is important to note that the
amplitude of such astrophysical noise is larger than both the signal of
Earth-like exoplanets and state-of-the-art instrumentation limit precision,
making this a pressing topic that needs to be addressed. In this chapter, I
present a general review of the main sources of noise in photometric and RV
observations, namely, stellar oscillations, granulation, and magnetic activity.
Moreover, for each noise source I discuss the techniques and observational
strategies which allow us to mitigate their impact.Comment: 11 pages, 2 tables, Lecture presented at the IVth Azores
International Advanced School in Space Sciences on "Asteroseismology and
Exoplanets: Listening to the Stars and Searching for New Worlds"
(arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in
July 201
Asteroseismology of Eclipsing Binary Stars in the Kepler Era
Eclipsing binary stars have long served as benchmark systems to measure
fundamental stellar properties. In the past few decades, asteroseismology - the
study of stellar pulsations - has emerged as a new powerful tool to study the
structure and evolution of stars across the HR diagram. Pulsating stars in
eclipsing binary systems are particularly valuable since fundamental properties
(such as radii and masses) can determined using two independent techniques.
Furthermore, independently measured properties from binary orbits can be used
to improve asteroseismic modeling for pulsating stars in which mode
identifications are not straightforward. This contribution provides a review of
asteroseismic detections in eclipsing binary stars, with a focus on space-based
missions such as CoRoT and Kepler, and empirical tests of asteroseismic scaling
relations for stochastic ("solar-like") oscillations.Comment: 28 pages, 12 figures, 2 tables; Proceedings of the AAS topical
conference "Giants of Eclipse" (AASTCS-3), July 28 - August 2 2013, Monterey,
C
Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star
A search of the time-series photometry from NASA's Kepler spacecraft reveals
a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626
with a period of 290 days. The characteristics of the host star are well
constrained by high-resolution spectroscopy combined with an asteroseismic
analysis of the Kepler photometry, leading to an estimated mass and radius of
0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for
the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the
planet. The system passes a battery of tests for false positives, including
reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A
full BLENDER analysis provides further validation of the planet interpretation
by showing that contamination of the target by an eclipsing system would rarely
mimic the observed shape of the transits. The final validation of the planet is
provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year
span. Although the velocities do not lead to a reliable orbit and mass
determination, they are able to constrain the mass to a 3{\sigma} upper limit
of 124 MEarth, safely in the regime of planetary masses, thus earning the
designation Kepler-22b. The radiative equilibrium temperature is 262K for a
planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is
a rocky planet, it is the first confirmed planet with a measured radius to
orbit in the Habitable Zone of any star other than the Sun.Comment: Accepted to Ap
KOI-3158: The oldest known system of terrestrial-size planets
The first discoveries of exoplanets around Sun-like stars have fueled efforts to find ever smaller worlds evocative of Earth and other terrestrial planets in the Solar System. While gas-giant planets appear to form preferentially around metal-rich stars, small planets (with radii less than four Earth radii) can form under a wide range of metallicities. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were far less abundant. We report Kepler spacecraft observations of KOI-3158, a metal-poor Sun-like star from the old population of the Galactic thick disk, which hosts five planets with sizes between Mercury and Venus. We used asteroseismology to directly measure a precise age of 11.2 ± 1.0 Gyr for the host star, indicating that KOI-3158 formed when the Universe was less than 20 % of its current age and making it the oldest known system of terrestrial-size planets. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, providing scope for the existence of ancient life in the Galaxy
Tocilizumab in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Background:
In this study, we aimed to evaluate the effects of tocilizumab in adult patients admitted to hospital with COVID-19 with both hypoxia and systemic inflammation.
Methods:
This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. Those trial participants with hypoxia (oxygen saturation <92% on air or requiring oxygen therapy) and evidence of systemic inflammation (C-reactive protein ≥75 mg/L) were eligible for random assignment in a 1:1 ratio to usual standard of care alone versus usual standard of care plus tocilizumab at a dose of 400 mg–800 mg (depending on weight) given intravenously. A second dose could be given 12–24 h later if the patient's condition had not improved. The primary outcome was 28-day mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN (50189673) and ClinicalTrials.gov (NCT04381936).
Findings:
Between April 23, 2020, and Jan 24, 2021, 4116 adults of 21 550 patients enrolled into the RECOVERY trial were included in the assessment of tocilizumab, including 3385 (82%) patients receiving systemic corticosteroids. Overall, 621 (31%) of the 2022 patients allocated tocilizumab and 729 (35%) of the 2094 patients allocated to usual care died within 28 days (rate ratio 0·85; 95% CI 0·76–0·94; p=0·0028). Consistent results were seen in all prespecified subgroups of patients, including those receiving systemic corticosteroids. Patients allocated to tocilizumab were more likely to be discharged from hospital within 28 days (57% vs 50%; rate ratio 1·22; 1·12–1·33; p<0·0001). Among those not receiving invasive mechanical ventilation at baseline, patients allocated tocilizumab were less likely to reach the composite endpoint of invasive mechanical ventilation or death (35% vs 42%; risk ratio 0·84; 95% CI 0·77–0·92; p<0·0001).
Interpretation:
In hospitalised COVID-19 patients with hypoxia and systemic inflammation, tocilizumab improved survival and other clinical outcomes. These benefits were seen regardless of the amount of respiratory support and were additional to the benefits of systemic corticosteroids.
Funding:
UK Research and Innovation (Medical Research Council) and National Institute of Health Research
Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial
Background:
Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19.
Methods:
This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.
Findings:
Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79).
Interpretation:
In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes.
Funding:
UK Research and Innovation (Medical Research Council) and National Institute of Health Research
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