Hypervelocity impact microfoil perforations in the LEO space environment (LDEF, MAP AO-023 experiment)

The Microabrasion Foil Experiment comprises arrays of frames, each supporting two layers of closely spaced metallic foils and a back-stop plate. The arrays, deploying aluminum and brass foil ranging from 1.5 to some 30 microns were exposed for 5.78 years on NASA's LDEF at a mean altitude of 458 km. They were deployed on the North, South, East, West, and Space pointing faces; results presented comprise the perforation rates for each location as a function of foil thickness. Initial results refer primarily to aluminum of 5 microns thickness or greater. This penetration distribution, comprising 2,342 perforations in total, shows significantly differing characteristics for each detector face. The anisotropy confirms, incorporating the dynamics of particulate orbital mechanics, the dominance of incorporating extraterrestrial particulates penetrating thicknesses greater than 20 microns in Al foil, yielding fluxes compatible with hyperbolic geocentric velocities. For thinner foils, a disproportionate increase in flux of particles on the East, North, and South faces shows the presence of orbital particulates which exceed the extraterrestrial component perforation rate at 5 micron foil thickness by a factor of approx. 4

Preliminary results from the dust flux monitoring instrument during the encounter of Stardust spacecraft with Wild-2 comet

On January 2, 2004, the Stardust spacecraft successfully encountered the Wild-2 comet. The Dust Flux Monitoring Instrument (DFMI) provided quantitative measurements of dust particle fluxes and particle mass distributions throughout the entire flythrough

Arboreal methodologies: Getting lost to explore the potential of the non-innocence of ‘nature’

This paper recounts a workshop that took place in a polytunnel in a forest school in Sligo, North-West Ireland on a cold day in early-December. The event sought to materialise ‘arboreal methodologies’ (Osgood, 2019; Osgood & Odegard, 2022; Osgood & Axelsson, 2023) which are characterised by the enactment of feminist posthumanist praxis to engage in world-making (Haraway, 2008) intended to unsettle recognisable tropes of biophilia that have come to frame both child and nature in narrow ways. The arboreal methodologies that adult participants were invited to mobilise were situated, material, affective, and involved metaphorical and material practices of ‘getting lost’ through ‘childing’. The workshop invited a sense of wonder at the ways arboreal methodologies might offer possibilities to confront human exceptionalism and wrestle with our complex, often contradictory relationships to ‘nature’ that might then go on to inform practice with young children. The approach taken involves methodologies without method (Koro-Ljunberg, 2016) to bring speculative, embodied encounters in the forest, together with unlikely tales of how forests work on and through us. We pursue a critical, tentacular engagement with the forest and take seriously its potential to agitate familiarity and strangeness, wonder and fear, nature and culture. In this paper we re-encounter embodied becomings-with the forest to think and sense other ways to take life in the Plantationocene (Tsing, 2015) seriously

The Role of Interpretive Evaluation in Engineering Information Systems Requirements

The requirements for complex systems inevitably change continuously. Any successful software or information systems engineering approach needs to observe this simple fact. This paper argues for the critical importance of formative evaluation activities in any non-sequential, or learning-based RE process. We argue that evaluation with its focus on understanding and interpreting the evaluation results, is distinct from measurement. We also outline how evaluation activities can be performed from an interpretivist perspective, in a way that systematically informs formative evaluation activities during gradual, experimental requirements engineering activities

Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia

The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear

Lepidopteran Granivory Reduces Seed Counts in a Rare Species of Riparian Scour Prairies

In Pennsylvania Baptisia australis var. australis is found along only four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Because of its limited distribution and small number of extant populations, the species is considered state-threatened in Pennsylvania. In addition, the riparian prairie habitat that Pennsylvania Baptisia australis var. australis is restricted to is also in decline and considered vulnerable. Because of these conservation concerns, insights into the natural history of the taxon in the state is valuable and will inform conservation efforts. Field surveys and fruit collections along the Allegheny River and herbarium collections were used to investigate and document granivory in Pennsylvania Baptisia australis var. australis, a phenomenon recorded in other parts of the species\u27 range, but not previously reported on in Pennsylvania. Using a model of best fit, the number of seeds found in fruit was found to be significantly impacted by the presence of granivores. We also report that visual surveys of fruits in the field are found to be accurate assessments of the presence and potential impact of granivores. In turn, our results will inform the conservation and management of Baptisia australis var. australis populations in Pennsylvania and highlight the importance of field surveys in protecting threatened taxa

Groundwater surface mapping informs sources of catchment baseflow

This work is funded by the Australian Research Council Discovery Project scheme through project DP120100253. We greatly appreciate the provision of groundwater chemistry data and introduction to the Gellibrand catchment by Alex Atkinson and Ian Cartwright from Monash University. We thank two anonymous reviewers and Ian Cartwright for their insightful and constructive reviews that helped improve this paper.Peer reviewedPublisher PD