Martian Gully Formation and Evolution: Studies From the Local to Global Scale

Gullies in the mid- and high-latitudes of Mars were first observed in Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images in 1997. Appearing to be geologically young, they quickly became a feature of interest due to the implication of liquid water in their formation based on distinct morphological characteristics including incised channels, many exhibiting features indicative of fluid flow. However, the temperature and pressure conditions on the surface of Mars during its most recent geologic era have not been conducive to sustaining water in the liquid phase for extended periods of time; therefore, a number of “wet” (water-related) and “dry” (driven by CO2 gas or granular flow) gully formation mechanisms have been proposed. The goal of this thesis is to conduct a large-scale study of gullies on Mars in order to determine how they are likely to have formed and evolved. I begin with a comprehensive global inventory of martian gullies to determine how their geographic distribution correlates with the effects of past and present climate conditions based on recent models, as well as thermophysical properties of the surface. Then I move to a regional focus in Utopia Planitia in Mars’ northern mid-latitudes, using gullies as a stratigraphic marker for the relative timing of formation of other mid-latitude landforms found in the region. Lastly, I take a localized approach within Gasa Crater, a particularly active gully site in the southern mid-latitudes, to investigate methods of looking for recent changes in martian gullies

Re-engineering the "leaky pipeline" metaphor: diversifying the pool by teaching STEM "by stealth"

Many attempts to engage diverse audiences in science, technology, engineering and mathematics (STEM) target students already enrolled or interested in STEM subjects. This paper presents qualitative findings on the characteristics and experiences of high school girls who participated in a STEM engagement programme involving drone-flying camps in two locations in regional northern Australia. As expected, the programme attracted students with a STEM interest, yet close to half of the participants named arts and humanities as their favourite subject areas. Our research suggests that engagement activities that primarily target students who already enjoy STEM will inhibit the capacity to attract diverse engineers. Programmes engaging with girls who do not identify as the "STEM type" may broaden engineering recruitment outcomes. Moreover, reimagining STEM beyond the boundaries of the traditional "hard sciences" works to overcome stereotyping that begins early in life (Bond, 2016; Kessels, 2015). We argue that the "pipeline" metaphor is part of the problem: it implies a singular pathway into engineering that is shaped by narrow curricular concepts of STEM education. Instead, we suggest that engineering disciplines should consider recruiting from a "deep pool"—one that recognises and values the dispositions generated through engagement with creative and critical curricula

The role of digital technologies in supporting quality improvement in Australian early childhood education and care settings

This national study explored the role of digital technologies in early childhood education and care settings and whether they could contribute to quality improvement as reported by educators and assessors of quality in Australia. In this paper, data from Stage 2 of the Quality Improvement Research Project were used, which comprised 60 Quality Improvement Plans from educators linked with 60 Assessment and Rating reports from the assessors who visited early childhood centres as part of the administration of the National Quality Standards by each of Australia’s State and Territory jurisdictions. Bronfenbrenner’s ecological systems theory (Bronfenbrenner, U. (1995).Developmental ecology through space and time: A future perspective. In P. Moen, G.H. Elder, Jr., & K. Lüscher (Eds.), Examining lives in context: Perspectives on the ecologyof human development (pp. 619 – 647). American Psychological Association. https://doi.org/10.1037/10176-018; Bronfenbrenner & Ceci, Bronfenbrenner and Ceci, Psychological Review 101:568 – 586, 1994) was adopted to facilitate a systemic and dynamic view on the use of digital technologies in these 60 ECEC settings. References (e.g. comments/ suggestions/ examples) made by the educators about the implementation of digital technologies were counted and thematically analysed. Results revealed the strong role new technologies (e.g. documentation and management platforms, tablets, apps, etc.) play in the majority of ECEC settings and especially in relation to three of the seven Quality Areas: Educational programme and practice (Quality Area 1); Collaborative partnerships with families and communities (Quality Area 6) and Governance and leadership (Quality Area 7). Future directions for research are suggested and implications for embracing a more holistic, integrated and broad view on the use of digital technologies are discussed

Temperature and rainfall are separate agents of selection shaping population differentiation in a forest tree

Research highlights: We present evidence indicating that covariation of functional traits among populations of a forest tree is not due to genetic constraints, but rather selective covariance arising from local adaptation to di erent facets of the climate, namely rainfall and temperature. Background and Aims: Traits frequently covary among natural populations. Such covariation can be caused by pleiotropy and/or linkage disequilibrium, but also may arise when the traits are genetically independent as a direct consequence of natural selection, drift, mutation and/or gene flow. Of particular interest are cases of selective covariance, where natural selection directly generates among-population covariance in a set of genetically independent traits. We here studied the causes of population-level covariation in two key traits in the Australian tree Eucalyptus pauciflora. Materials and Methods: We studied covariation in seedling lignotuber size and vegetative juvenility using 37 populations sampled from throughout the geographic and ecological ranges of E. pauciflora on the island of Tasmania. We integrated evidence from multiple sources: (i) comparison of patterns of trait covariation within and among populations; (ii) climate-trait modelling using machine-learning algorithms; and (iii) selection analysis linking trait variation to field growth in an arid environment. Results: We showed strong covariation among populations compared with the weak genetic correlation within populations for the focal traits. Population di erentiation in these genetically independent traits was correlated with di erent home-site climate variables (lignotuber size with temperature; vegetative juvenility with rainfall), which spatially covaried. The role of selection in shaping the population di erentiation in lignotuber size was supported by its relationship with fitness measured in the field. Conclusions: Our study highlights the multi-trait nature of adaptation likely to occur as tree species respond to spatial and temporal changes in climateinfo:eu-repo/semantics/publishedVersio

Leaf Economic and Hydraulic Traits Signal Disparate Climate Adaptation Patterns in Two Co-Occurring Woodland Eucalypts

With climate change impacting trees worldwide, enhancing adaptation capacity has become an important goal of provenance translocation strategies for forestry, ecological renovation, and biodiversity conservation. Given that not every species can be studied in detail, it is important to understand the extent to which climate adaptation patterns can be generalised across species, in terms of the selective agents and traits involved. We here compare patterns of genetic-based population (co)variation in leaf economic and hydraulic traits, climate–trait associations, and genomic differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-yearold trees growing in a common-garden trial established with progeny from populations of both species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania, Australia. Despite originating from the same climatic gradients, the species differed in their levels of population variance and trait covariance, patterns of population variation within each species were uncorrelated, and the species had different climate–trait associations. Further, the pattern of genomic differentiation among populations was uncorrelated between species, and population differentiation in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to explain this decoupling of patterns and propose that the choice of seed provenances for climatebased plantings needs to account for multiple dimensions of climate change unless species-specific information is availableinfo:eu-repo/semantics/publishedVersio

Hypotheses for the Origin of the Hypanis Fan-Shaped Deposit at the Edge of the Chryse Escarpment, Mars: Is it a Delta?

We investigated the origin of the fan-shaped deposit at the end of Hypanis Valles that has previously been proposed as an ExoMars, Mars 2020, and human mission candidate landing site, and found evidence that the landform is an ancient delta. Previous work suggests that the deposit originated from a time of fluvial activity both distinct from and prior to catastrophic outflow, and crater counting placed the deposit’s age at  ≥ 3.6 Ga. We found over 30 thin sedimentary strata in the proposed delta wall, and from our slope analysis conclude that the fluvial sequence is consistent with a lowering/retreating shoreline. We measured nearly horizontal bedding dip angles ranging from 0° to 2° over long stretches of cliff and bench exposures seen in HiRISE images and HiRISE stereo DTMs. From THEMIS night IR images we determined that the fan-shaped deposit has a low thermal inertia (150-240 Jm-2 K-1 s-1/2) and the surrounding darker-toned units correspond to thermal inertia values as high as 270-390 Jm-2 K-1 s-1/2. We interpret these findings to indicate that the fan-shaped deposit consists mostly of silt-sized and possibly finer grains, and that the extremely low grade and large lateral extent of these beds implies that the depositional environment was calm and relatively long-lived. We interpret the geomorphology and composition as incompatible with an alluvial fan or mudflow hypothesis. From our stratigraphic mapping we interpret the order of events which shaped the region. After the Chryse impact, sediment filled the basin, a confined lake or sea formed allowing a large delta to be deposited near its shoreline, the water level receded to the north, darker sedimentary/volcanic units covered the region and capped the light-toned deposit as hydro-volcanic eruptions shaped the interior of Lederberg crater, freeze/thaw cycles and desiccation induced local fracturing, and finally wrinkle ridges associated with rounded cones warped the landscape following trends in degraded crater rims and existing tectonic features. The ancient deltaic deposit we observe today was largely untouched by subsequent catastrophic outflows, and its surface has been only moderately reshaped by over 3 billion years of aeolian erosion

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Multiscale scenarios for nature futures

Targets for human development are increasingly connected with targets for nature, however, existing scenarios do not explicitly address this relationship. Here, we outline a strategy to generate scenarios centred on our relationship with nature to inform decision-making at multiple scales