Challenging dyke ascent models using novel laboratory experiments: Implications for reinterpreting evidence of magma ascent and volcanism

Volcanic eruptions are fed by plumbing systems that transport magma from its source to the surface, mostly fed by dykes. Here we present laboratory experiments that model dyke ascent to eruption using a tank filled with a crust analogue (gelatine, which is transparent and elastic) that is injected from below by a magma analogue (dyed water). This novel experimental setup allows, for the first time, the simultaneous measurement of fluid flow, sub-surface and surface deformation during dyke ascent. During injection, a penny-shaped fluid-filled crack is formed, intrudes, and traverses the gelatine slab vertically to then erupt at the surface. Polarised light shows the internal stress evolution as the dyke ascends, and an overhead laser scanner measures the surface elevation change in the lead-up to dyke eruption. Fluorescent passive-tracer particles that are illuminated by a laser sheet are monitored, and the intruding fluid's flow dynamics and gelatine's sub-surface strain evolution is measured using particle image velocimetry and digital image correlation, respectively. We identify 4 previously undescribed stages of dyke ascent. Stage 1, early dyke growth: the initial dyke grows from the source, and two fluid jets circulate as the penny-shaped crack is formed. Stage 2, pseudo-steady dyke growth: characterised by the development of a rapidly uprising, central, single pseudo-steady fluid jet, as the dyke grows equally in length and width, and the fluid down-wells at the dyke margin. Sub-surface host strain is localised at the head region and the tail of the dyke is largely static. Stage 3, pre-eruption unsteady dyke growth: an instability in the fluid flow appears as the central fluid jet meanders, the dyke tip accelerates towards the surface and the tail thins. Surface deformation is only detected in the immediate lead-up to eruption and is characterised by an overall topographic increase, with axis-symmetric topographic highs developed above the dyke tip. Stage 4 is the onset of eruption, when fluid flow is projected outwards and focused towards the erupting fissure as the dyke closes. A simultaneous and abrupt decrease in sub-surface strain occurs as the fluid pressure is released. Our results provide a comprehensive physical framework upon which to interpret evidence of dyke ascent in nature, and suggest dyke ascent models need to be re-evaluated to account for coupled intrusive and extrusive processes and improve the recognition of monitoring signals that lead to volcanic eruptions in nature

Rings in the Solar System: a short review

Rings are ubiquitous around giant planets in our Solar System. They evolve jointly with the nearby satellite system. They could form either during the giant planet formation process or much later, as a result of large scale dynamical instabilities either in the local satellite system, or at the planetary scale. We review here the main characteristics of rings in our solar system, and discuss their main evolution processes and possible origin. We also discuss the recent discovery of rings around small bodies.Comment: Accepted for the Handbook of Exoplanet

Motivations and barriers to prosthesis users participation in physical activity, exercise and sport : a review of the literature

The UK will host the Paralympics in 2012 and the Commonwealth Games in 2014 showcasing the talents of elite athletes and aiming to inspire the population to become involved. However, low levels of physical activity (PA) are prevalent: only 40% of men and 28% of women meet the minimum UK recommendations. The limb absent population is no exception. To determine if people with limb amputations are participating in physical activity and sport; whether post-amputation activity levels match pre-amputation levels; and if there are motivations and barriers to participation. Study design: Literature review Five reviewers systematically search of peer reviewed and gray literature in seven bibliographic databases and the Cochrane Library. Results: Following rigorous elimination, 12 articles were finally included in the review and critically appraised. Four themes were identified: components, rehabilitation outcomes, body image and motivations and barriers to participation. People with limb absence are not participating in PA conducive to health benefits, and only a minority participate in exercise and sports. Participation following amputation does not mirror that of pre-amputation levels, and more barriers than motivations exist to adopting and maintaining a physically active lifestyle. This literature review aims to inform those involved in rehabilitation and ongoing care of those with limb absence about what motivates or precludes their participation in physical activity, exercise and sport. Such knowledge could be applied to improving health and well being in this population

Exploring local spatial features in hyperspectral image

We propose a methodological framework to extract spatial features in hyperspectral imaging data and establish a link between these features and the spectral regions, capturing the observed structural patterns. The proposed approach consists of five main steps: i) two dimensional Stationary Wavelet Transform (2D-SWT) is applied to a hyperspectral data cube, decomposing each single-channel image with a selected wavelet filter up to the maximum decomposition level; ii) a grey-level co-occurrence matrix is calculated for every 2D-SWT image resulting from stage i); iii) distinctive spatial features are determined by computing morphological descriptors from each grey-level co-occurrence matrix; iv) the morphological descriptors are rearranged in a two dimensional data array; v) this data matrix is subjected to Principal Component Analysis (PCA) for exploring the variability of the aforementioned descriptors across spectral channels. As a result, groups of spectral wavelengths associated to specific spatial features can be pointed out yielding a better understanding and interpretation of the data. In principle, this information can also be further exploited, e.g. to improve the separation of pure spectral profiles in a multivariate curve resolution context

Q methodology and a Delphi poll: a useful approach to researching a narrative approach to therapy

Q methodology and a Delphi poll combined qualitative and quantitative methods to explore definitions of White and Epston's (1990) narrative approach to therapy among a group of UK practitioners. A Delphi poll was used to generate statements about narrative therapy. The piloting of statements by the Delphi panel identified agreement about theoretical ideas underpinning narrative therapy and certain key practices. A wider group of practitioners ranked the statements in a Q sort and made qualitative comments about their sorting. Quantitative methods (principal components analysis) were used to extract eight accounts of narrative therapy, five of which are qualitatively analysed in this paper. Agreement and differences were identified across a range of issues, including the social construction of narratives, privileging a political stance or narrative techniques and the relationship with other therapies, specifically systemic psychotherapy. Q methodology, combined with the Delphi poll, was a unique and innovative feature of this study

Engaging with community researchers for exposure science: lessons learned from a pesticide biomonitoring study

A major challenge in biomonitoring studies with members of the general public is ensuring their continued involvement throughout the necessary length of the research. The paper presents evidence on the use of community researchers, recruited from local study areas, as a mechanism for ensuring effective recruitment and retention of farmer and resident participants for a pesticides biomonitoring study. The evidence presented suggests that community researchers' abilities to build and sustain trusting relationships with participants enhanced the rigour of the study as a result of their on-the-ground responsiveness and flexibility resulting in data collection beyond targets expected

A demonstration of an affinity between pyrite and organic matter in a hydrothermal setting

One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in central Ireland. Here, the organic matter is accumulated as coatings around, and through, pyrite grains. Most of the pyrite grains are euhedral-subhedral crystals, ranging in size from ca 0.1-0.5 mm in diameter, and they are scattered throughout the matrix of the vein calcite. The organic matter was deposited from a hydrothermal fluid at a temperature of at least 200°C, and gives a Raman signature of disordered carbon. This study points to an example from a hydrothermal setting in the geological record, demonstrating that pyrite can have a high potential for the concentration and accumulation of organic materials

Workload and workflow implications associated with the use of electronic clinical decision support tools used by health professionals in general practice: a scoping review

This is the final version. Available from BMC via the DOI in this record. All data generated or analysed during this study are included in this published article.BACKGROUND: Electronic clinical decision support tools (eCDS) are increasingly available to assist General Practitioners (GP) with the diagnosis and management of a range of health conditions. It is unclear whether the use of eCDS tools has an impact on GP workload. This scoping review aimed to identify the available evidence on the use of eCDS tools by health professionals in general practice in relation to their impact on workload and workflow. METHODS: A scoping review was carried out using the Arksey and O'Malley methodological framework. The search strategy was developed iteratively, with three main aspects: general practice/primary care contexts, risk assessment/decision support tools, and workload-related factors. Three databases were searched in 2019, and updated in 2021, covering articles published since 2009: Medline (Ovid), HMIC (Ovid) and Web of Science (TR). Double screening was completed by two reviewers, and data extracted from included articles were analysed. RESULTS: The search resulted in 5,594 references, leading to 95 full articles, referring to 87 studies, after screening. Of these, 36 studies were based in the USA, 21 in the UK and 11 in Australia. A further 18 originated from Canada or Europe, with the remaining studies conducted in New Zealand, South Africa and Malaysia. Studies examined the use of eCDS tools and reported some findings related to their impact on workload, including on consultation duration. Most studies were qualitative and exploratory in nature, reporting health professionals' subjective perceptions of consultation duration as opposed to objectively-measured time spent using tools or consultation durations. Other workload-related findings included impacts on cognitive workload, "workflow" and dialogue with patients, and clinicians' experience of "alert fatigue". CONCLUSIONS: The published literature on the impact of eCDS tools in general practice showed that limited efforts have focused on investigating the impact of such tools on workload and workflow. To gain an understanding of this area, further research, including quantitative measurement of consultation durations, would be useful to inform the future design and implementation of eCDS tools.The Dennis and Mireille Gillings FoundationCancer Research UKUniversity of ExeterUniversity of Exeter Medical Schoo

Kinematic Edges with Flavor Oscillation and Non-Zero Widths

Kinematic edges in cascade decays provide a probe of the masses of new particles. In some new physics scenarios the decay chain involves intermediate particles of different flavors that can mix and oscillate. We discuss the implication of such oscillation, and in particular its interplay with the non-zero widths of the particles. We derive explicit formulae for differential decay rates involving both non-zero widths and oscillation, and show that in the case where the mass difference between the intermediate particle is of the order of their widths, both oscillation and width effects are important. An examination of the physical observables contained in these differential decay rates is provided. We calculate differential decay rates for cases in which the intermediate particles are either scalars or fermions.Comment: 28 pages, 6 figure