Evidence of Erosional Self-Channelization of Pyroclastic Density Currents Revealed by Ground-Penetrating Radar Imaging at Mount St. Helens, Washington (USA)

The causes and effects of erosion are among the least understood aspects of pyroclastic density current (PDC) dynamics. Evidence is especially limited for erosional self-channelization, a process whereby PDCs erode a channel that confines the body of the eroding flow or subsequent flows. We use ground-penetrating radar imaging to trace a large PDC scour and fill from outcrop to its point of inception and discover a second, larger PDC scour and fill. The scours are among the largest PDC erosional features on record, at \u3e200 m wide and at least 500 m long; estimated eroded volumes are on the order of 106 m3. The scours are morphologically similar to incipient channels carved by turbidity currents. Erosion may be promoted by a moderate slope (5–15°), substrate pore pressure retention, and pulses of increased flow energy. These findings are the first direct evidence of erosional self-channelization by PDCs, a phenomenon that may increase flow velocity and runout distance through confinement and substrate erosion

Engaging the public in delivering health improvement: Research Briefing

Involving members of the public in delivering public health programmes offers a way to utilise the knowledge, skills and resources within communities. Many health promotion projects involve volunteers or lay health workers; they carry out activities such as peer support and peer education, signposting to services and running community groups. Engaging citizens in co-producing health and wellbeing can help services tackle health inequalities by improving connections with less advantaged groups and by shaping provision to better meet community needs. This research briefing considers what active citizens can do for services and how services can best engage, support and sustain a community or volunteer workforce in order to improve health outcomes. It provides practical guidance on the steps that need to be taken to redesign services and maximise the long term benefits: • deciding what people can contribute to health improvement • choosing a service model • recruiting, training and supporting people in their roles • changing systems to support citizen engagement. This research briefing is based on the findings of the ‘People in Public Health’ study, independent research conducted by Leeds Metropolitan University and funded though the National Institute for Health Research Service Delivery and Organisation Programme. The research examined approaches to support members of the public who take on public health roles, with a focus on the Choosing Health priorities

The geological history of Nili Patera, Mars

Nili Patera is a 50 km diameter caldera at the center of the Syrtis Major Planum volcanic province. The caldera is unique among Martian volcanic terrains in hosting: (i) evidence of both effusive and explosive volcanism, (ii) hydrothermal silica, and (iii) compositional diversity from olivine-rich basalts to silica-enriched units. We have produced a new geological map using three mosaicked 18 m/pixel Context Camera digital elevation models, supplemented by Compact Remote Imaging Spectrometer for Mars Hyperspectral data. The map contextualizes these discoveries, formulating a stratigraphy in which Nili Patera formed by trapdoor collapse into a volcanotectonic depression. The distinctive bright floor of Nili Patera formed either as part of a felsic pluton, exposed during caldera formation, or as remnants of welded ignimbrite(s) associated with caldera formation—both scenarios deriving from melting in the Noachian highland basement. After caldera collapse, there were five magmatic episodes: (1) a basaltic unit in the caldera's north, (2) a silica-enriched unit and the associated Nili Tholus cone, (3) an intrusive event, forming a ~300 m high elliptical dome; (4) an extrusive basaltic unit, emplaced from small cones in the east; and (5) an extreme olivine-bearing unit, formed on the western caldera ring fault. The mapping, together with evidence for hydrated materials, implies magmatic interaction with subsurface volatiles. This, in an area of elevated geothermal gradient, presents a possible habitable environment (sampled by the hydrothermal deposits). Additionally, similarities to other highland volcanoes imply similar mechanisms and thus astrobiological potential within those edifices

Designing expert hearings: how to use deliberative research methods for public health evidence

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People in Public Health – A Study of Approaches to Develop and Support People in Public Health Roles

‘People in Public Health’ is a study about approaches to develop and support lay people in public health roles. The use of participatory approaches in public health programmes, both in national and international contexts, is well established and seen as necessary to deliver sustainable improvements in public health (Bracht and Tsouros, 1990; Rifkin et al., 2000; World Health Organization, 2002). Indeed a central argument in the Wanless reviews was that a ‘fully engaged scenario’ with high levels of public engagement in health would result in lower levels of public expenditure and better health outcomes (Wanless, 2002; Wanless, 2004). Government policy supports greater community engagement in health as a means of addressing public health priorities and tackling health inequalities (Department of Health, 2003). The health agenda on community involvement resonates with arguments for citizen empowerment and greater democratisation of services, not only in the NHS but across the public sector, in national agencies and local authorities (Campbell et al., 2008). Recent national guidance on community engagement noted the wide variety of approaches, indicating that those approaches based on higher levels of participation and greater community control were more likely to lead to increased health and social outcomes1 (National Institute for Health and Clinical Effectiveness, 2008). There was a recommendation to recruit what were termed ‘agents of change’ in communities who become involved ‘to plan, design and deliver health promotion activities and to help address the wider social determinants of health’ by taking on roles such as peer educators, health champions or neighbourhood wardens (National Institute for Health and Clinical Effectiveness, 2008:28). The concept of empowerment, the process of individuals and communities being enabled to undertake local action to effect change, is seen as core to health promotion (Tones and Tilford, 2001; World Health Organization, 1986; Wallerstein, 2006). Government policy on community empowerment advocates increased citizen involvement in planning and running services (Secretary of State for Communities and Local Government, 2008) and this agenda is linked to the personalisation of health and social services and patient and public involvement (Department of Health, 2005b; Department of Health, 2006; Secretary of State for Health, 2006). More evidence is required, however, about effective mechanisms for lay engagement and how public services can best enhance, support and sustain community involvement

A one-shot deviation principle for stability in matching problems

This paper considers marriage problems, roommate problems with nonempty core, and college admissions problems with responsive preferences. All stochastically stable matchings are shown to be contained in the set of matchings which are most robust to one-shot deviation

Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile

Unconsolidated pyroclastic flow deposits of the 1993 eruption of Lascar Volcano, Chile, have, with time, become increasingly dissected by a network of deeply penetrating fractures. The fracture network comprises orthogonal sets of decimeter-wide linear voids that form a pseudo-polygonal grid visible on the deposit surface. In this work, we combine shallow surface geophysical imaging tools with remote sensing observations and direct field measurements of the deposit to investigate these fractures and their underlying causal mechanisms. Based on ground penetrating radar images, the fractures are observed to have propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to 1 cm/year occurred between 1993 and 1996 with continued subsidence occurring at a slower rate thereafter. In situ measurements show that 1 m below the surface, the 1993 deposits remain 5°C to 15°C hotter, 18 years after emplacement, than adjacent deposits. Based on the observed subsidence as well as estimated cooling rates, the fractures are inferred to be the combined result of deaeration, thermal contraction, and sedimentary compaction in the months to years following deposition. Significant environmental factors, including regional earthquakes in 1995 and 2007, accelerated settling at punctuated moments in time. The spatially variable fracture pattern relates to surface slope and lithofacies variations as well as substrate lithology. Similar fractures have been reported in other ignimbrites but are generally exposed only in cross section and are often attributed to formation by external forces. Here we suggest that such interpretations should be invoked with caution, and deformation including post-emplacement subsidence and fracturing of loosely packed ash-rich deposits in the months to years postemplacement is a process inherent in the settling of pyroclastic material

An observational study of quality of motion in the aging cervical spine: sequence of segmental contributions in dynamic fluoroscopy recordings.

BACKGROUND: The term 'physiological motion of the spine' is commonly used although no proper definition exists. Previous work has revealed a consistent sequence of cervical segmental contributions in 80-90% of young healthy individuals. Age has been shown to be associated with a decreased quantity of motion. Therefore, it is of interest to study whether this sequence persists throughout aging. The aim of this prospective cohort study is to investigate if the consistent sequence of cervical segmental contributions in young asymptomatic individuals remains present in elderly asymptomatic individuals. METHODS: In this prospective cohort study, dynamic flexion to extension cinematographic recordings of the cervical spine were made in asymptomatic individuals aged 55-70 years old. Individuals without neck pain and without severe degenerative changes were included. Two recordings were made in each individual with a 2-to-4-week interval (T1 and T2). Segmental rotation of each individual segment between C4 and C7 was calculated to determine the sequence of segmental contributions. Secondary outcomes were segmental range of motion (sRoM) and sagittal alignment. RESULTS: Ten individuals, with an average age of 61 years, were included. The predefined consistent sequence of segmental contributions was found in 10% of the individuals at T1 and 0% at T2. sRoM and total range of motion (tRoM) were low in all participants. There was no statistically significant correlation between sagittal alignment, degeneration and sRoM in the respective segments, nor between cervical lordosis and tRoM. CONCLUSIONS: This study shows that aging is associated with loss of the consistent motion pattern that was observed in young asymptomatic individuals. The altered contribution of the cervical segments during extension did not appear to be correlated to the degree of degeneration or sagittal alignment. Trial registration clinicaltrials.gov NCT04222777, registered 10.01.2020

Services just for men? Insights from a national study of the well men services pilots.

Men continue to have a lower life expectancy in most countries compared to women. Explanations of this gendered health inequality tend to focus on male risk taking, unhealthy lifestyle choices and resistance to seeking help from health services. In the period 2005-2008 the Scottish Government funded a nationwide community health promotion programme aimed at improving men's health, called Well Men Service Pilots (henceforth WMS)