Transitions between effusive and explosive activity at Merapi volcano, Indonesia: a volcanological and petrological study of the 2006 and 2010 eruptions.

The 2010 explosive eruption (VEI 4) of Merapi volcano, Indonesia, was the volcano’s largest since 1872. In contrast, volcanism over the last century has been characterised by dome-building and gravitational dome collapse, such as in 2006 (VEI 1). The driving forces behind effusive and explosive activity, as well as factors that affect transitions in eruptive style are investigated through petrological and textural analysis, using the well-documented 2006 and 2010 eruptions as case-studies. Pre- and syn-eruptive crystallisation and degassing processes are examined via whole rock geochemical analysis, mineral compositions and thermobarometry, quantitative textural analysis of feldspar microlites and analysis of volatiles and light lithophile elements in melt inclusions. These data were gathered from a detailed set of stratigraphically controlled samples, correlated to eruptive chronology and style, which were collected during several field campaigns. Both the 2006 and 2010 eruptions produced basaltic andesite, similar in terms of major and trace element compositions. A major zone of crystallisation is proposed at between ~ 14 and 29 km depth, although crystallisation occurs throughout the crust. Magmatic temperatures are estimated to be ~920–1020 °C. Maximum H2O contents reach 3.94 wt.% in 2010 melt inclusions and up to 3.73 wt.% in those from 2006. CO2 concentrations are < 200 ppm, although they may reach up to 695 ppm in some melt inclusions from the 2010 eruption. An exsolved brine phase was present during both eruptions which “buffered” melt Cl concentrations and enriched Li at shallow depths within the conduit or edifice. Eruptive style and transitions at Merapi are linked to magma ascent rate, crystallisation and open- and closed-degassing processes, which can be influenced by magma influx. The findings of this work are crucial for understanding the full range of eruptive behaviour that Merapi is capable of producing

Geological history, chronology and mMagmatic evolution of Merapi

This chapter provides a synthesis of the geological history, chronology and magmatic evolution of Merapi. Stratigraphic field and geochronological data are used to divide Merapi into three main evolutionary stages and associated volcanic edifices (Proto-, Old and New Merapi) and eight broad volcano-stratigraphic units to characterise the eruptive activity and structural evolution of the volcano through time. Complementary petrological, geochemical and isotopic data are used to characterise the eruptive products of Merapi and shed light on the geochemical evolution and petrogenetic processes. The data indicate that the eruptive products of Merapi are mainly basaltic andesite of both medium-K and high-K type and support a two-stage petrogenetic model, where primary magmas are derived from a heterogenous, Indian Ocean MORB-like mantle source metasomatised by slab-derived components. Subsequently, these magmas are modified during transfer through the crust by complex magmatic differentiation processes, including contamination by carbonate rocks of the local upper crust. The available data indicate that, since ~ 1900 14C y BP, the lavas and pyroclastic rocks of Merapi are essentially of the high-K type and that regular geochemical variations with systematic shifts in whole rock SiO2 content occurred since at least the Late Holocene, although erupted magma compositions have remained broadly uniform since the mid-twentieth century

PrEdiction of Risk and Communication of outcomE followIng major lower limb amputation – a collaboratiVE study (PERCEIVE): Protocol for the PERCEIVE qualitative study

INTRODUCTION: Deciding whether to proceed with a major lower limb amputation is life-changing and complex, and it is crucial that the right decision is made at the right time. However, medical specialists are known to poorly predict risk when assessing patients for major surgery, and there is little guidance and research regarding decisions about amputation. The process of shared decision-making between doctors and patients during surgical consultations is also little understood. Therefore, the aim of this study is to analyse in depth the communication, consent, risk prediction and decision-making process in relation to major lower limb amputation. METHODS AND ANALYSIS: Consultations between patients and surgeons at which major lower limb amputation is discussed will be audio-recorded for 10–15 patients. Semi-structured follow-up interviews with patients (and relatives/carers) will then be conducted at two time points: as soon as possible/appropriate after a decision has been reached regarding surgery, and approximately 6 months later. Semi-structured interviews will also be conducted with 10–15 healthcare professionals working in the UK National Health Service (NHS) involved in amputation decision-making. This will include surgeons, anaesthetists and specialist physiotherapists at 2–4 NHS Health Boards/Trusts in Wales and England. Discourse analysis will be used to analyse the recorded consultations; interviews will be analysed thematically. Finally, workshops will be held with patients and healthcare professionals to help synthesise and interpret findings. ETHICS AND DISSEMINATION: The study has been approved by Wales REC 7 (20/WA/0351). Study findings will be published in international peer-reviewed journal(s) and presented at national and international scientific meetings. Findings will also be disseminated to a wide NHS and lay audience via presentations at meetings and written summaries for key stakeholder groups

The PERCEIVE quantitative study: PrEdiction of Risk and Communication of outcome following major lower limb amputation: protocol for a collaboratiVE study

BACKGROUND: Accurate prediction of outcomes following surgery with high morbidity and mortality rates is essential for informed shared decision-making between patients and clinicians. It is unknown how accurately healthcare professionals predict outcomes following major lower-limb amputation (MLLA). Several MLLA outcome-prediction tools have been developed. These could be valuable in clinical practice, but most require validation in independent cohorts before routine clinical use can be recommended. The primary aim of this study is to evaluate the accuracy of healthcare professionals’ predictions of outcomes in adult patients undergoing MLLA for complications of chronic limb-threatening ischaemia (CLTI) or diabetes. Secondary aims include the validation of existing outcome-prediction tools. METHOD: This study is an international, multicentre prospective observational study including adult patients undergoing a primary MLLA for CLTI or diabetes. Healthcare professionals’ accuracy in predicting outcomes at 30-days (death, morbidity and MLLA revision) and 1-year (death, MLLA revision and ambulation) will be evaluated. Sixteen existing outcome-prediction tools specific to MLLA will be examined for validity. Data collection began on 1 October 2020; the end of follow-up will be 1 May 2022. The C-statistic, Hosmer–Lemeshow test, reclassification tables and Brier score will be used to evaluate the predictive performance of healthcare professionals and prediction tools, respectively. STUDY REGISTRATION AND DISSEMINATION: This study will be registered locally at each centre in accordance with local policies before commencing data collection, overseen by local clinician leads. Results will be disseminated to all centres, and any subsequent presentation(s) and/or publication(s) will follow a collaborative co-authorship model

Kailo: a systemic approach to addressing the social determinants of young people’s mental health and wellbeing at the local level [version 1; peer review: awaiting peer review]

The mental health and wellbeing of children and young people is deteriorating. It is increasingly recognised that mental health is a systemic issue, with a wide range of contributing and interacting factors. However, the vast majority of attention and resources are focused on the identification and treatment of mental health disorders, with relatively scant attention on the social determinants of mental health and wellbeing and investment in preventative approaches. Furthermore, there is little attention on how the social determinants manifest or may be influenced at the local level, impeding the design of contextually nuanced preventative approaches. This paper describes a major research and design initiative called Kailo that aims to support the design and implementation of local and contextually nuanced preventative strategies to improve children's and young people’s mental health and wellbeing. The Kailo Framework involves structured engagement with a wide range of local partners and stakeholders - including young people, community partners, practitioners and local system leaders - to better understand local systemic influences and support programmes of youth-centred and evidence-informed co-design, prototyping and testing. It is hypothesised that integrating different sources of knowledge, experience, insight and evidence will result in better embedded, more sustainable and more impactful strategies that address the social determinants of young people’s mental health and wellbeing at the local level

Transitions between explosive and effusive phases during the cataclysmic 2010 eruption of Merapi volcano, Java, Indonesia

Transitions between explosive and effusive activity are commonly observed during dome-forming eruptions and may be linked to factors such as magma influx, ascent rate and degassing. However, the interplay between these factors is complex and the resulting eruptive behaviour often unpredictable. This paper focuses on the driving forces behind the explosive and effusive activity during the well-documented 2010 eruption of Merapi, the volcano’s largest eruption since 1872. Time-controlled samples were collected from the 2010 deposits, linked to eruption stage and style of activity. These include scoria and pumice from the initial explosions, dense and scoriaceous dome samples formed via effusive activity, as well as scoria and pumice samples deposited during subplinian column collapse. Quantitative textural analysis of groundmass feldspar microlites, including measurements of areal number density, mean microlite size, crystal aspect ratio, groundmass crystallinity and crystal size distribution analysis, reveal that shallow pre- and syn-eruptive magmatic processes acted to govern the changing behaviour during the eruption. High-An (up to ∼80 mol% An) microlites from early erupted samples reveal that the eruption was likely preceded by an influx of hotter or more mafic magma. Transitions between explosive and effusive activity in 2010 were driven primarily by the dynamics of magma ascent in the conduit, with degassing and crystallisation acting via feedback mechanisms, resulting in cycles of effusive and explosive activity. Explosivity during the 2010 eruption was enhanced by the presence of a ‘plug’ of cooled magma within the shallow magma plumbing system, which acted to hinder degassing, leading to overpressure prior to initial explosive activity

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001). Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice

Risk of SARS-CoV-2 reinfection during multiple Omicron variant waves in the UK general population

SARS-CoV-2 reinfections increased substantially after Omicron variants emerged. Large-scale community-based comparisons across multiple Omicron waves of reinfection characteristics, risk factors, and protection afforded by previous infection and vaccination, are limited. Here we studied ~45,000 reinfections from the UK’s national COVID-19 Infection Survey and quantified the risk of reinfection in multiple waves, including those driven by BA.1, BA.2, BA.4/5, and BQ.1/CH.1.1/XBB.1.5 variants. Reinfections were associated with lower viral load and lower percentages of self-reporting symptoms compared with first infections. Across multiple Omicron waves, estimated protection against reinfection was significantly higher in those previously infected with more recent than earlier variants, even at the same time from previous infection. Estimated protection against Omicron reinfections decreased over time from the most recent infection if this was the previous or penultimate variant (generally within the preceding year). Those 14–180 days after receiving their most recent vaccination had a lower risk of reinfection than those &gt;180 days from their most recent vaccination. Reinfection risk was independently higher in those aged 30–45 years, and with either low or high viral load in their most recent previous infection. Overall, the risk of Omicron reinfection is high, but with lower severity than first infections; both viral evolution and waning immunity are independently associated with reinfection