95 research outputs found
Revision of the solid geology shown on the 'Assynt District' special geological map : a report on the 2002 fieldwork
The report provides an overview of the main findings from the first field season in the Assynt
District of the Moine Thrust Project. Detailed mapping in the eastern part of the Assynt halfwindow has resulted in a new interpretation of the geometry and behaviour of the Ben More
Thrust. This reinterpretation of the thrust satisfactorily resolves the conflicts between the various
previous models. The remapping confirmed that the Ben More Thrust can be traced, as shown on
the published 1923 Assynt District geological map, along the western flank of Na Tuadhan to
Bealach aâ Mhadhaidh. The Ben More Thrust is then traced to [NC 30026 24416] where it is
displaced across a steep reverse fault to [NC 30514 23953]. It then continues NNW as a readily
traceable feature placing gneisses of the Lewisian Gneiss Complex over quartzite along Leathaid
Riabhach [NC 298 252]. Here the Ben More Thrust progressively steepens into a sub-vertical
structure that has gneiss to the NE and quartzite to the SW. The thrust follows a prominent gully
along Leathaid Riabhach to Aâ Chailleach. From here the Ben More Thrust more or less follows
the top of a monoclinally folded quartzite that forms the summit of Beinn Uidhe and is exposed
in the valley floor NW of Aâ Chailleach. It retains thrust geometry with hangingwall gneisses
and footwall quartzites and becomes a steep feature that approximately follows âGlen Beagâ (the
un-named glen south of the Stack of Glencoul). The Ben More Thrust meets, but does not
displace the Glencoul Thrust at the head of Loch Glencoul. Therefore it is proposed that there is
a branch line here where the two thrusts meet so that all the rocks NE of Loch Glencoul and east
of Loch Beag are part of the Ben More Thrust Sheet. Figure 2.7 in the report provides a clear
pictorial description of the geometry of the Ben More Thrust in the northern part of the Assynt
half-window.
A significant new ductile structure has been identified within the Ben More Thrust Sheet, termed
the Coire aâ Mhadhaidh Detachment, that mostly follows the Lewisian gneisses/quartzite contact.
It has been traced from the northern limits of the Loch Ailsh intrusion across Ben More Assynt,
along the eastern slopes of Na Tuadhan, across Cailleach an t-Sniomha to the west of Gorm Loch
MĂČr and immediately west of the Stack of Glencoul into Glen Coul (Figure 2.1 in the report).
The sense of shearing in the detachment is almost always top-to-west. Similar smaller shears
have also been recognised within the Lewisian gneisses in the thrust sheet. However, no ductile
shearing was noted at the gneiss/quartzite contact below the Ben More Thrust.
Several of the complex imbricate structures mapped by previous workers were revisited. The
imbricates in the Loch an EircillâLoch nan Caorach area appear to be simpler than shown on the
published Assynt District map. An alternative solution is provided for the southern termination
of the Glencoul Thrust south of Inchnadamph although it is noted that more detailed work needs
to be done, notably south of Conival.
Brief descriptions are given of Moine rocks above the Moine Thrust in the north-eastern part of
the Assynt District map. There appears to be a lateral facies change with semipelitic schists
dominant in upper Glen Cassley and psammites becoming dominant to the north. Fabrics
associated with several deformation phases have largely obliterated sedimentary structures
although transposed bedding traces can be seen between a spaced foliation that controls the
flaggy character of the psammites.
Widely spaced traverses across the major Lewisian outcrop areas, within the Assynt half-window
as well as in the western foreland to the thrust belt, largely confirmed the work of the primary
surveyors. Thus all of the Lewisian comprises orthogneisses, mostly hornblende-gneisses but
with more felsic pyroxene-bearing gneisses in the north, that all contain ultramafic and mafic pods and layers. The traces of the various Scourie dykes are correctly shown on the published
Assynt District map. The Canisp Shear Zone has been traced eastwards, south of Canisp,
eventually disappears under Cambrian quartzites. A second parallel shear has also been
delineated north of Loch Assynt. The polyphase nature of ductile deformation in the Lewisian
gneisses elucidated by previous workers is confirmed. However, the deformation state of the
gneisses is extremely variable on all scales, with intense deformation confined to specific (shear)
zones that vary in thickness from several centimetres up to hundreds of metres.
Descriptions of the numerous minor intrusions and the Quaternary deposits studied during the
fieldwork are given in separate reports
UK monitoring and deposition of tephra from the May 2011 eruption of GrĂmsvötn, Iceland
Mapping the transport and deposition of tephra is important for the assessment of an eruptionâs impact on health, transport, vegetation and infrastructure, but it is challenging at large distances from a volcano (>â1000 km), where it may not be visible to the naked eye. Here we describe a range of methods used to quantify tephra deposition and impact on air quality during the 21â28 May 2011 explosive basaltic eruption of GrĂmsvötn volcano, Iceland. Tephra was detected in the UK with tape-on-paper samples, rainwater samples, rainwater chemistry analysis, pollen slides and air quality measurements. Combined results show that deposition was mainly in Scotland, on 23â25 May. Deposition was patchy, with adjacent locations recording different results. Tape-on-paper samples, collected by volunteer citizen scientists, and giving excellent coverage across the UK, showed deposition at latitudes >55°N, mainly on 24 May. Rainwater samples contained ash grains mostly 20â30 ÎŒmâlong (maximum recorded grainsize 80 ÎŒm) with loadings of up to 116 grainscm-2. Analysis of rainwater chemistry showed high concentrations of dissolved Fe and Al in samples from N Scotland on 24â27 May. Pollen slides recorded small glass shards (3â4 ÎŒmâlong) deposited during rainfall on 24â25 May and again on 27 May. Air quality monitoring detected increased particulate matter concentrations in many parts of the country. An hourly concentration of particles â53°N) on 24 May but no negative effects on health were reported. Although the eruption column reached altitudes of 20 km above sea level, air mass trajectories suggest that only tephra from the lowest 4 km above sea level of the eruption plume was transported to the UK. This demonstrates that even low plumes could deliver tephra to the UK and suggests that the relative lack of basaltic tephra in the tephrochronological record is not due to transport processes
Identification of new susceptibility loci for osteoarthritis (arcOGEN):a genome-wide association study
To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Osteoarthritis is the most common form of arthritis worldwide and is a major cause of pain and disability in elderly people. The health economic burden of osteoarthritis is increasing commensurate with obesity prevalence and longevity. Osteoarthritis has a strong genetic component but the success of previous genetic studies has been restricted due to insufficient sample sizes and phenotype heterogeneity. We undertook a large genome-wide association study (GWAS) in 7410 unrelated and retrospectively and prospectively selected patients with severe osteoarthritis in the arcOGEN study, 80% of whom had undergone total joint replacement, and 11,009 unrelated controls from the UK. We replicated the most promising signals in an independent set of up to 7473 cases and 42,938 controls, from studies in Iceland, Estonia, the Netherlands, and the UK. All patients and controls were of European descent. We identified five genome-wide significant loci (binomial test pâ€5·0Ă10(-8)) for association with osteoarthritis and three loci just below this threshold. The strongest association was on chromosome 3 with rs6976 (odds ratio 1·12 [95% CI 1·08-1·16]; p=7·24Ă10(-11)), which is in perfect linkage disequilibrium with rs11177. This SNP encodes a missense polymorphism within the nucleostemin-encoding gene GNL3. Levels of nucleostemin were raised in chondrocytes from patients with osteoarthritis in functional studies. Other significant loci were on chromosome 9 close to ASTN2, chromosome 6 between FILIP1 and SENP6, chromosome 12 close to KLHDC5 and PTHLH, and in another region of chromosome 12 close to CHST11. One of the signals close to genome-wide significance was within the FTO gene, which is involved in regulation of bodyweight-a strong risk factor for osteoarthritis. All risk variants were common in frequency and exerted small effects. Our findings provide insight into the genetics of arthritis and identify new pathways that might be amenable to future therapeutic intervention.Arthritis Research UK
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Role of genetic testing for inherited prostate cancer risk: Philadelphia prostate cancer consensus conference 2017
Purpose: Guidelines are limited for genetic testing for prostate cancer (PCA). The goal of this conference was to develop an expert consensus-dri
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
Relationship of edge localized mode burst times with divertor flux loop signal phase in JET
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM
Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages
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Growth of the lava dome and extrusion rates at Soufriere Hills Volcano, Montserrat, West Indies : 2005-2008
The third episode of lava dome growth at SoufriĂšre Hills Volcano began 1 August 2005 and ended 20 April 2007. Volumes of the dome and talus produced were measured using a photoâbased method with a calibrated camera for increased accuracy. The total dense rock equivalent (DRE) volume of extruded andesite magma (306 ± 51 Mm3) was similar within error to that produced in the earlier episodes but the average extrusion rate was 5.6 ± 0.9 m3sâ1 (DRE), higher than the previous episodes. Extrusion rates varied in a pulsatory manner from <0.5 m3sâ1 to âŒ20 m3sâ1. On 18 May 2006, the lava dome had reached a volume of 85 Mm3 DRE and it was removed in its entirety during a massive dome collapse on 20 May 2006. Extrusion began again almost immediately and built a dome of 170 Mm3 DRE with a summit height 1047 m above sea level by 4 April 2007. There were few moderateâsized dome collapses (1â10 Mm3) during this extrusive episode in contrast to the first episode of dome growth in 1995â8 when they were numerous. The first and third episodes of dome growth showed a similar pattern of low (<0.5 m3sâ1) but increasing magma flux during the early stages, with steady high flux after extrusion of âŒ25 Mm3
Clyde Gateway Pilot 3D Geological and Groundwater Model
This report describes the Clyde Gateway Pilot 3D geological model (superficial deposits, bedrock) and groundwater model (recharge and groundwater flow) which covers 1:10,000 scale Ordnance Survey sheets NS66SW, NS66NW and NS56SE. The groundwater model considers a broader area in general, and also, for practical purposes, a detailed consideration of NS56NE, based on available hydrogeological data. Therefore, the models, and report, address not only the Clyde Gateway area itself, but a larger area which includes for example the alignments of the M74 Extension and East End Regeneration Route.
The report provides background information to the model user including brief geological descriptions, model construction methods, uncertainty factors, limitations and a helpful 3D model user manual
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