I’ll have what he’s having: A unique example of elite emulation in late New Kingdom mummification

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Continuous monitoring of mixing depth with radon-222 and lidar

We report on the development of a combined approach using both lidar and radon-222 measurements to obtain a near-continuous record of mixing depth which can, in turn, be used to assist in the interpretation of simultaneous trace gas measurements. Interactions between the land surface and the atmosphere above are moderated by the strength and depth of mixing in the lower atmosphere which ranges diurnally between several meters at night to over one kilometer during the day. Elastic backscatter lidar can be used to measure the depth of mixing during the day, i.e. the height of the planetary boundary layer (PBL), by employing the change in aerosol concentration, and hence lidar signal, at the boundary between the PBL and the free atmosphere. These measurements are only possible when the mixing depth is large. A complimentary approach, based on radon measurements, works well from the time turbulence decays in the afternoon through till mid morning when mixing depths are too small to be observed using lidar. Radon- 222 is chemically inert and is released from the surface at a relatively constant rate and as such is a natural passive tracer. Since it is radioactive, with a half-life of 3.8 days, it does not accumulate in the atmosphere. At horizontally homogeneous inland sites, vertical mixing is the main process affecting near-surface concentration. An estimate can therefore be obtained of an “equivalent mixing depth” from time-series of radon concentration measurements, which can themselves be obtained with robust and low-maintenance instrumentation. Using two measurement techniques sidesteps the limitations of each to make a combined dataset a useful component of field studies which seek to understand the exchanges of trace gases between the land surface and atmosphere

Return of the Sea Monster – a tale from D’Urville Island, New Zealand

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Crystal and magnetic structure of (1− x) BiFeO3–xSrTiO3 (x= 0.2, 0.3, 0.4 and 0.8)

The effect of doping SrTiO3 into BiFeO3 on the magnetic and crystal structure has been explored using powder neutron diffraction for where x=0.2, 0.3, 0.4, 0.6 and 0.8. While the data are not sensitive to the cycloidal component of the magnetic ordering, the evolution of the collinear antiferromagnetic moment of the G-type antiferromagnetic component with T and x has been explored, as have structural parameters. It is found that for pure phase samples form in the R3c cell, and for x=0.8 a non-magnetic phase is obtained. The x=0.6 sample gives a mixed phase. Through the R3c phase the magnetic structure does not change appreciably apart from the reduction of magnetic moment magnitude with the increasing T and/or x. © 2013 Elsevier Inc

Silver nanoparticles prepared by gamma irradiation across metal organic framework templates

In this study, we demonstrate for the first time the successful fabrication of well-dispersed ultrafine silver nanoparticles inside metal–organic frameworks through a single step gamma irradiation at room temperature. HKUST-1 crystals are soaked in silver nitrate aqueous solution and irradiated with a Cobalt 60 source across a range of irradiation doses to synthesize highly uniformly distributed silver nano-particles. The average size of the silver nanoparticles across the Ag@HKUST-1 materials is found to vary between 1.4 and 3 nm for dose exposures between 1 and 200 kGy, respectively. The Ag@HKUST-1 hybrid crystals exhibit strong surface plasmon resonance and are highly durable and efficient catalytic materials for the reduction of 4-nitrophenol to 4-aminophenol (up to 14.46 × 10−3 s−1 for 1 kGy Ag@HKUST-1). The crystals can be easily recycled for at least five successive cycles of reaction with a conversion efficiency higher than 99.9%. The gamma irradiation is demonstrated to be an effective and environmental friendly process for the synthesis of nano-particles across confined metal–organic frameworks at room temperature with potential applications in environmental science. © 2015 The Royal Society of Chemistr

Radiosynthesis, in vivo biological evaluation, and imaging of brain lesions with [123I]-CLINME, a new SPECT tracer for the translocator protein

The high affinity translocator protein (TSPO) ligand 6-chloro-2-(4′-iodophenyl)-3-(N,N-methylethyl)imidazo[1,2-a]pyridine-3-acetamide (CLINME) was radiolabelled with iodine-123 and assessed for its sensitivity for the TSPO in rodents. Moreover neuroinflammatory changes on a unilateral excitotoxic lesion rat model were detected using SPECT imaging. [123I]-CLINME was prepared in 70–80% radiochemical yield. The uptake of [123I]-CLINME was evaluated in rats by biodistribution, competition, and metabolite studies. The unilateral excitotoxic lesion was performed by injection of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid unilaterally into the striatum. The striatum lesion was confirmed and correlated with TSPO expression in astrocytes and activated microglia by immunohistochemistry and autoradiography. In vivo studies with [123I]-CLINME indicated a biodistribution pattern consistent with TPSO distribution and the competition studies with PK11195 and Ro 5-4864 showed that [123I]-CLINME is selective for this site. The metabolite study showed that the extractable radioactivity was unchanged [123I]-CLINME in organs which expresses TSPO. SPECT/CT imaging on the unilateral excitotoxic lesion indicated that the mean ratio uptake in striatum (lesion : nonlesion) was 2.2. Moreover, TSPO changes observed by SPECT imaging were confirmed by immunofluorescence, immunochemistry, and autoradiography. These results indicated that [123I]-CLINME is a promising candidate for the quantification and visualization of TPSO expression in activated astroglia using SPECT. © 2015 F. Mattner et al

Spatial and temporal variation in carbon storage in subtropical seagrass meadows

Seagrass meadows are one of three habitats that serve as marine carbon sinks, preserving up to thousands of years of carbon stored in their sediments. However, seagrass meadows are highly threatened and are continuing to decline worldwide. Seagrass management and conservation initiatives require adequate understanding of the spatial and temporal variability of carbon storage in these ecosystems, which is currently limited. This study aimed to identify how varying environmental and biological conditions influence spatial and temporal variability of carbon storage in subtropical seagrass meadows. Seagrass biomass and sediment cores were collected between the years 2012 and 2013 at multiple locations across a water quality gradient within Moreton Bay, Australia. The number of cores collected were 298 biomass cores, 298 shallow sediment cores, and 20 deeper sediment cores of up to 2 m sediment depth. Sediment carbon content and seagrass structural complexitywere determined for each location. Environmental variables were determined from field data (water quality) and modelled data (wave height). Spatial variability of carbon content was found among sites and linked to variations in seagrass canopy complexity, water turbidity, depth and wave energy. Sediment isotopic composition varied among locations, indicating variations in the contribution of carbon sources. Seasonal variability was limited and overshadowed by spatial variability. Millennial variation was observed, by dating the deeper sediment cores using 210PB and 14C. Carbon content, vertical accretion, isotopic composition, and carbon accumulation rates varied through the sediment column in Moreton Bay and were higher following European settlement. This study provides comprehensive results on spatial and temporal variability of seagrass sediments in Moreton Bay, which provides useful information for the developmentand implementation of blue carbon conservation and management initiatives

The future of radiotracing

Radiotracing has enormous potential to provide data to underpin environmental management in aquatic ecosystems. The use of tracer data to validate numerical models, improvements in data acquisition and new tracer forms provide the basis for the future of radiotracing. However, an increasing regulatory burden, reduction in tracer availability and a loss of technical expertise threaten this field of study. Standardisation of tracer approaches where possible and new work on assessing the impact of radiotracers on non-human biota are two areas that may enable the future use of radiotracers at a field scale in engineering and research applications. © The authors.International Atomic Energy Agenc

Ochre through the late Quaternary at Gledswood Shelter 1, northwest Queensland

Gledswood Shelter 1 (GS1) is a sandstone rockshelter located in northwest Queensland containing archaeological evidence for human occupation dating from at least 35 ka to the recent past. Considerable quantities of ochre fragments (many with striations caused by grinding) have been recovered from the 2.5 m deep cultural sequence, particularly in the pre-LGM levels. The abundance of ochre varies through time, in line with recovered stone artefacts, suggesting that these materials reflect different periods and intensities of site use. This evidence possibly indicates that the production of painted or stencilled art in this region may be earlier than previous evidence suggests (ca 9,000 years ago). The GS1 ochre samples were initially characterised according to visual characteristics including colour, texture and inclusions using low powered microscopy. This work suggests there are several groups of pigment present, including fragments that would more normally be referred to as ironstone and not considered as an 'ochre', but that have anthropogenic ground surfaces indicating their use as a source of pigment. In this paper we present the initial characterisation and preliminary neutron activation analysis results of the GS1 ochres, and consider their implications for the human history of the northwest Queensland region

Debris flow dominated alluvial fans in the Victorian high country indicate that landscape denudation through the Holocene has been dominated by post-bushfire runoff events

Bushfires play a major role in shaping the Australian landscape. Whilst the role of fire in shaping and changing vegetation assemblages is relatively well understood, there is still debate about the significance of fire in driving landscape denudation, relative to other processes, such as major rainfall and flood events. Studies of post-fire landscape impact of recent bushfires indicate that the response is sensitive to the frequency and magnitude of extreme bushfires and intense rainstorms, with the greatest response occurring when storms occur in the post-fire period before vegetation has recovered. Where storm events occur shortly after a major bushfire, hillslope erosion is enhanced, due to debris flows and erosion of both primary hillslope sediment and sediment stored in hillslope channel networks. We excavated nine trenches, in five alluvial fans at the base of hillslopes on the floodplain of the Nariel valley, northeast Victoria. This area was burnt by the 1939 and 2003 bushfires, although some of the fans were unburnt in 2003. The trenches were up to 3.5 m deep, and in four cases intersected the underlying floodplain sediment at the base of the trench, indicating that they provide a full record of sedimentation for that sector of the fan. Fan stratigraphy consisted of sub-horizontal (parallel to the fan surface) units 0.3–0.5 m thick, with occasional units 1–1.2m thick, and cross-cutting channelized units. Debris flow deposits accounted for 80–90 % of the observed sediments, with water-laid gravels and soil units forming the remainder. Most soil layers were burnt, and most (but not all) debris flow units contained charcoal. A typical stratigraphy consisted of 6–8 debris flow units per fan, with four units containing a fire signature or overlying a burnt soil layer. Radiocarbon dating of the fireassociated units is underway: preliminary results will be reported at the AQUA meeting