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We investigate the turbulence statistics in a multiphase plume made of heavy particles (particle Reynolds number at terminal velocity is 450). Using refractive-index-matched stereoscopic particle image velocimetry, we measure the locations of particles whose buoyancy drives the formation of a multiphase plume, together with the local velocity of the induced flow in the ambient salt–water. Measurements of the mean axial flow in the plume centreplane follow Gaussian profiles and that of the mean radial flow is consistent with integral plume theory. The turbulence characteristics resemble those measured in a bubble plume, including strong anisotropy in the normal Reynolds stresses. However, we observe structural differences between the two multiphase plumes. First, the skewness of the probability density function of the axial velocity fluctuations is not that which would be predicted by simply reversing the direction of a bubble plume. Second, in contrast to a bubble plume, the particle plume has a non-negligible fluid-shear production term in the turbulent kinetic energy (TKE) budget. Third, the radial decay of all measured terms in the TKE budget is slower than those in a bubble plume. Despite these dissimilarities, a bigger picture emerges that applies to both flows. The TKE production by particles (or bubbles) roughly balances the viscous dissipation, except near the plume centreline. The one-dimensional power spectra of the velocity fluctuations show a
power law that puts both the particle and bubble plume in a category different from single-phase shear-flow turbulence.
Isotope ratios of tooth enamel from ten Early Neolithic individuals buried in a long cairn at Whitwell in central England were measured to determine where they sourced their childhood diet. Five individuals have low Sr concentrations (11–66 ppm) and high 87Sr/86Sr ratios (0.7164–0.7212). Three individuals have relatively low 87Sr/86Sr ratios (0.712–0.711) and Sr concentrations ranging between 54 and 109 ppm. Two individuals have strontium isotope values that bridge the gap between the isotope compositions of these two groups. The high 87Sr/86Sr values are rare in human enamel and exclude sources within the biosphere of central England. Oxygen isotope values are comparable to those found within human archaeological populations buried in temperate regions of Europe. The strontium isotope results should be interpreted in the context of other evidence for migration from northern France to Britain during the Early Neolithic.
The nature of landscape use and residence patterns during the British earlier Neolithic has often been debated. Here we use strontium and oxygen isotope analysis of tooth enamel, from individuals buried at the Hambledon Hill causewayed enclosure monument complex in Dorset, England to evaluate patterns of landscape use during the earlier Neolithic. Previous analysis suggests that a significant proportion of the artefacts found at the site may originate from lithology of Eocene and Upper to Middle Jurassic age that the enclosures overlook to the immediate west and south. The excavators therefore argued that the sector of landscape visible from Hambledon Hill provides an approximate index for the catchment occupied by the communities that it served. Most of the burial population exhibit isotope ratios that could be consistent with this argument. Connections between Hambledon Hill and regions much further afield are also hypothesised, based on the presence of artefacts within the assemblage that could have been sourced from lithology in Somerset, Devon, and Cornwall in south-west England. However, few of the sampled individuals have strontium isotope ratios consistent with having obtained the majority of their diet from such areas during childhood. The individuals who exhibit the highest strontium isotope ratios are all adult males, whom the excavators suggest to have died during one or more episodes of conflict, following the burning and destruction of surrounding defensive outworks built during the 36th century bc. At least one of these individuals, who was found with an arrowhead amongst his ribs, did not obtain his childhood diet locally and has 87Sr/86Sr values that could be comparable to those bioavailable in the south-west peninsula.
Red Supergiant Stars (RSGs) are important probes of stellar and chemical evolution in star-forming environments. They represent the brightest near-IR stellar components of external galaxies and probe the most recent stellar population to provide robust, independent abundance estimates. The Local Group dwarf irregular galaxy, NGC6822, is a reasonably isolated galaxy with an interesting structure and turbulent history. Using RSGs as chemical abundance probes, we estimate metallicities in the central region of NGC6822, finding a suggestion of a metallicity gradient (in broad agreement with nebular tracers), however, this requires further study for confirmation. With intermediate resolution Multi-object spectroscopy (from e.g. KMOS, EMIR, MOSFIRE) combined with state-of-the-art stellar model atmospheres, we demonstrate how RSGs can be used to estimate stellar abundances in external galaxies. In this context, we compare stellar and nebular abundance tracers in NGC 6822 and by combining stellar and nebular tracers we estimate an abundance gradient of −0.18 ± 0.05 dex/kpc.
Metal–insulator–metal (MIM) resonant absorbers comprise a conducting ground plane, a thin dielectric, and thin separated metal top-surface structures. The dielectric SiO2 strongly absorbs near 9 µm wavelength and has correspondingly strong long-wave-infrared (LWIR) dispersion for the refractive index. This dispersion results in multiple absorption resonances spanning the LWIR, which can enhance broad-band sensitivity for LWIR bolometers. Similar considerations apply to silicon nitride Si3N4. TiO2 and AlN have comparatively low dispersion and give simple single LWIR resonances. These dispersion-dependent features for infrared MIM devices are demonstrated by experiment, electrodynamic simulation, and an analytic model based on standing waves.
Ternary lead chalcogenides, such as PbSxSe1-x, offer the possibility of room-temperature infrared detection with engineered cut-off wavelengths within the important 3-5 micron mid-wave infrared (MWIR) wavelength range. We present growth and characterization of aqueous spray-deposited thin films of PbSSe. Complexing agents in the aqueous medium suppress unwanted homogeneous reactions so that growth occurs only by the heterogeneous reaction on the hydrophilic substrate. The strongly-adherent films are smooth with a mirror-like finish. The films comprise densely packed grains with tens of nm dimensions and a total film thickness of ∼400-500 nm. Measured optical constants reveal absorption out to at least 4.5 μm wavelength and a ∼0.3 eV bandgap intermediate between those of PbS and PbSe. The semiconducting films are p-type with resistivity ∼1 and 85 Ohm-cm at 300 and 80 K, respectively. Sharp x-ray diffraction peaks identify the films as Clausthalite-Galena solid-state solution with a lattice constant that indicates an even mixture of PbS and PbSe. The photoconductive response is observed at both nitrogen and room temperature up to at least 2 kHz chopping frequency.
The development of algorithms for agile science and autonomous exploration has been pursued in contexts ranging from spacecraft to planetary rovers to unmanned aerial vehicles to autonomous underwater vehicles. In situations where time, mission resources and communications are limited and the future state of the operating environment is unknown, the capability of a vehicle to dynamically respond to changing circumstances without human guidance can substantially improve science return. Such capabilities are difficult to achieve in practice, however, because they require intelligent reasoning to utilize limited resources in an inherently uncertain environment. Here we discuss the development, characterization and field performance of two algorithms for autonomously collecting water samples on VALKYRIE (Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer), a glacier-penetrating cryobot deployed to the Matanuska Glacier, Alaska (Mission Control location: 61°42′09.3″N 147°37′23.2″W). We show performance on par with human performance across a wide range of mission morphologies using simulated mission data, and demonstrate the effectiveness of the algorithms at autonomously collecting samples with high relative cell concentration during field operation. The development of such algorithms will help enable autonomous science operations in environments where constant real-time human supervision is impractical, such as penetration of ice sheets on Earth and high-priority planetary science targets like Europa.
Niemann–Pick type C (NP-C) disease is a rare neurodegenerative lysosomal storage disorder. It is highly heterogeneous, and there is limited awareness of a substantial subgroup that has an attenuated adolescent/adult-onset disease. In these patients psychiatric features, often a psychosis, may dominate the initial impression, although often there is an associated ataxia and cognitive impairment. Typically, patients experience a substantial diagnostic delay. In this review we highlight the importance of early recognition and discuss the pathophysiology, neuropsychiatric presentation and recent changes in the investigation and work-up of these patients, and treatment options.
Patients who experience Transient Ischaemic Attack (TIA) should be assessed and treated in a specialist clinic to reduce risk of further TIA or stroke. But referrals are often delayed. We aimed to identify published studies describing pathways for emergency assessment and referral of patients with suspected TIA at first medical contact: primary care; ambulance services; and emergency department.
We conducted a scoping literature review. We searched four databases (PubMed, CINAHL, Web of Science, Scopus). We screened studies for eligibility. We extracted and analysed data to describe setting, assessment and referral processes reported in primary research on referral of suspected TIA patients directly to specialist outpatient services.
We identified eight studies in nine papers from five countries: 1/9 randomized trial; 6/9 before-and-after designs; 2/9 descriptive account. Five pathways were used by family doctors and three by Emergency Department (ED) physicians. None were used by paramedics. Clinicians identified TIA patients using a checklist incorporating the ABCD2 tool to describe risk of further stroke, online decision support tool or clinical judgement. They referred to a specialist clinic, either directly or via a telephone helpline. Anti-platelet medication was often given, usually aspirin unless contraindicated. Some patients underwent neurological and blood tests before referral and discharge. Five studies reported reduced incident of stroke at 90 days, from 6–10 percent predicted rate to 1.2-2.1 percent actual rate. Between 44 percent and 83 percent of suspected TIA cases in these studies were directly referred to stroke clinics through the pathways.
Research literature has focused on assessment and referral by family doctors and ED physicians to reduce hospitalization of TIA patients. No pathways for paramedic use were reported. Since many suspected TIA patients present to ambulance services, effective pre-hospital assessment and referral pathways are needed. We will use review results to develop a paramedic referral pathway to test in a feasibility trial.
Transient Ischaemic Attack (TIA) is a neurologic event with symptom resolution within 24 hours. Early specialist assessment of TIA reduces risk of stroke and death. National United Kingdom (UK) guidelines recommend patients with TIA are seen in specialist clinics within 24 hours (high risk) or seven days (low risk).
We aimed to develop a complex intervention for patients with low risk TIA presenting to the emergency ambulance service. The intervention is being tested in the TIER feasibility trial, in line with Medical Research Council (MRC) guidance on staged development and evaluation of complex interventions.
We conducted three interrelated activities to produce the TIER intervention:
•Survey of UK Ambulance Services (n = 13) to gather information about TIA pathways already in use
•Scoping review of literature describing prehospital care of patients with TIA
•Synthesis of data and definition of intervention by specialist panel of: paramedics; Emergency Department (ED) and stroke consultants; service users; ambulance service managers.
The panel used results to define the TIER intervention, to include:
1.Protocol for paramedics to assess patients presenting with TIA and identify and refer low risk patients for prompt (< 7day) specialist review at TIA clinic
2.Patient Group Directive and information pack to allow paramedic administration of aspirin to patients left at home with referral to TIA clinic
3.Referral process via ambulance control room
4.Training package for paramedics
5.Agreement with TIA clinic service provider including rapid review of referred patients
We followed MRC guidance to develop a clinical intervention for assessment and referral of low risk TIA patients attended by emergency ambulance paramedic. We are testing feasibility of implementing and evaluating this intervention in the TIER feasibility trial which may lead to fully powered multicentre randomized controlled trial (RCT) if predefined progression criteria are met.
Addition of wavelength selective absorbers on microbolometers tends to increase their thermal mass and slow their infrared response times. Making the bolometric material an integral part of the absorber and minimizing layer thicknesses is one possible way to maintain high detector speeds. Here, we study experimentally the effect on permittivity of adding a layer of semiconducting VOx between two layers of SiO2. Additionally, we investigate theoretically the effect on resonance wavelength of thinning the metal in metal-insulator-metal plasmonic resonant absorbers.
Blanket mire is a rare resource representing less than 3% (120 000 km2) of global peatlands (Tallis 1997). The largest concentration of blanket mire occurs in the uplands of the UK and Ireland (approximately 20% of global blanket mire (Tallis 1998)). The global rarity of blanket mire and concerns over its current condition in the UK (see Box 9.1) have led to it being included in protective legislation (European Commission 1992) and in national conservation strategies (JNCC and DEFRA 2012).
Blanket mire condition in the UK has been impacted by multiple pressures, including drainage, afforestation, atmospheric pollution and burning. The most intensely impacted areas are severely eroded, with large areas of bare peat and erosion gully networks (Evans and Warburton 2007), with artificial drainage additionally affecting over 1.5 million hectares of blanket mire (Parry et al. 2014). Although the extent of erosion of blanket mire in the UK and Ireland is not widely replicated elsewhere in the world, analogous peat erosion has been reported from North and South America, Asia and Australia (Evans and Warburton 2007). For example, increasing levels of erosion of sloping mires in Tibet (Joosten and Schumann 2007; Chapter 13) demonstrate that the requirement to manage upland peat is not just a UK concern. The focus of this chapter is therefore on the ecosystem service benefits of blanket mire restoration in the uplands of the UK and Ireland, as an exemplar for peatland restoration which may become more widely applicable.
The chapter is in three sections. The first summarises the main ecosystem services of blanket mire; the second describes the main drivers for the condition of blanket mire in the UK; and the third outlines the impact that blanket mire restoration has on ecosystem services. Readers are also directed to the review by Parry et al. (2014), which provides further details on blanket mire degradation, the restoration techniques employed in the UK and the response of ecosystem service features to restoration practices.
Ecosystem services from blanket mire systems
Blanket mires contribute a range of ecosystem services, briefly summarised below following the proposed Common International Standard for Ecosystem Services (Haines-Young and Potschin 2013; see Table 1.1 in Chapter 1).
Hydrological processes strongly control the form and function of peatlands, since the flow of water, dissolved minerals and nutrients dictates the biodiversity and nature of the plant community (Bridgham and Richardson 1993; Zoltai and Vitt 1995) and production and decomposition dynamics (Moore et al. 2002) that result in the accumulation of peat. Vegetation and peat, in turn influence the hydrology through their effect on surface flow (Quinton and Hayashi 2005), groundwater (Siegel and Glaser 1987) and evapotranspiration (Lafleur et al. 2005). The functional links between plants, peat and water constitute a strongly coupled eco-hydrological feedback system.
There are many approaches to peatland classification (Moore 1984), reflecting in part the closely coupled plant–soil–water system. Because of the fundamental link between peat formation and hydrological conditions, it may be argued that hydrological status is a primary criterion in the classification of peatlands. The most basic distinction between two main mire types, bogs and fens, is based on water source. Fens receive minerogenous (rich in dissolved minerals) surface- and groundwater inputs in addition to precipitation. Bogs are peatlands that are entirely ombrogenous (fed only by precipitation) and often develop over fens (Kuhry et al. 1993), as the accumulating peat raises the elevation of the surface and the water table, isolating them from minerogenous water inputs. Further subdivisions of fen and bog are commonly identified through their hydrogeomorphic setting (Brinson 1993; Charman 2002), which is arguably a proxy for water source and water-table regime. In North America, minerogeneous systems are commonly further divided into swamps and fens (NWWG 1997). This distinction is drawn based on vegetation cover (swamps are forested while fens support graminoid and brown moss species), but, in fact, because of the strong plant–water coupling this reflects varying hydrological status with swamps characterised by a strongly variable water table (that allows tree growth), while fen systems have stable high water tables. In maritime climates, such as that of the British Isles and in Newfoundland, very high rainfall supports the development of ‘blanket’ bogs particularly in upland areas. Blanket bogs are laterally extensive, blanketing the pre-existing topography. Consequently, they typically include both true bog and areas where upslope drainage is a significant component of the water budget (although that drainage in intact mires may be nutrient-poor waters sourced from upslope bogs).
For most of human history the smelting of metallic ores has been performed immediately adjacent to the ore body. In the 1830s the copper industry that was centred on Swansea in the UK departed abruptly from that ancient pattern: Swansea smelters shipped in ores from very distant locations, including sites in Australasia, Latin America, and southern Africa. Swansea became the hub of a globally integrated heavy industry, one that deployed capital on a very large scale, implanted British industrial technologies in some very diverse settings, and mobilized a transnational workforce that included British-born ‘labour aristocrats’, Chinese indentured servants, and African slaves. This paper explores the World of Copper between its inception c.1830 and its demise in the aftermath of the American Civil War. It asks what the experience of this precociously globalized industry can contribute to some current concerns in global history.
To explore experiences of psychiatrists considering medication for patients with personality disorder by analysis of transcribed, semi-structured interviews with consultants.
Themes show important relational processes in which not prescribing is expected to be experienced as uncaring rejection, and psychiatrists felt helpless and inadequate as doctors when unable to relieve symptoms by prescribing. Discontinuity in doctor–patient relationships compounds these problems.
Problems arise from: (a) the psychopathology creating powerful relational effects in consultation; (b) the lack of effective treatments, both actual and secondary to under-resourcing and neglect of non-pharmaceutical interventions; and (c) the professionally constructed role of psychiatrists prioritising healing and cure through provision of technological interventions for specific diagnoses. There is a need for more treatments and services for patients with personality disorder; more support and training for psychiatrists in the relational complexities of prescribing; and a rethink of the trend for psychiatrists to be seen primarily as prescribers.
Fundamental mode classical Cepheids have light curves which repeat accurately enough that we can watch them evolve (change period). The new level of accuracy and quantity of data with the Kepler and MOST satellites probes this further. An intriguing result was found in the long time-series of Kepler data for V1154 Cyg the one classical Cepheid (fundamental mode, P = 4.9 d) in the field, which has short term changes in period (≃20 minutes), correlated for ≃10 cycles (period jitter). To follow this up, we obtained a month long series of observations of the fundamental mode Cepheid RT Aur and the first overtone pulsator SZ Tau. RT Aur shows the traditional strict repetition of the light curve, with the Fourier amplitude ratio R1/R2 remaining nearly constant. The light curve of SZ Tau, on the other hand, fluctuates in amplitude ratio at the level of approximately 50%. Furthermore prewhitening the RT Aur data with 10 frequencies reduces the Fourier spectrum to noise. For SZ Tau, considerable power is left after this prewhitening in a complicated variety of frequencies.