Understanding the interplay of temperature and moisture on the germination niche to improve management of threatened species impacted by mining

The return of vegetation to mined lands often requires broadcast seeding of diverse native seed mixes. However, seeds are highly adapted to germination windows with specific hydrothermal thresholds that maximize the likelihood of seedling survival, and post-mining landscapes typically offer markedly different hydrothermal conditions than pre-disturbance ecosystems. According to niche theory, generalist species should exhibit broader hydrothermal performance niches than specialist taxa, which may influence the success of recruitment from seeds in post-mining ecological restoration. To test this assumption, the impact of hydrothermal stress (incubation temperature (10–30°C) and osmotic potential (−0.8 to 0 MPa)) on the time to 50% germination (t50) and maximum germination (Gmax) was compared between two narrow-range species of conservation concern (Acacia woodmaniorum and A. karina) restricted to mining-impacted Banded Ironstone Formations (BIF) and three broadly distributed congenerics (A. assimilis, A. exocarpoides, and A. ramulosa). The hydrothermal germination niches of the study species were broadly congruent with hydrothermal conditions of their habitats. The two range-restricted taxa were more tolerant of hydrothermal stress compared to the three widely distributed taxa, suggesting that tolerance of greater hydrothermal stress by both range-restricted Acacia species is likely to be adaptive to establishment in uncontested niche space. Complex interactions between thermal and water stress suggest these environmental gradients may shape the germination niche as well as patterns of plant diversity in BIF ecosystems. This study highlights the importance of quantifying interactions between niche dimensions and their implications for species performance, which will aid future restoration efforts for micro-endemic species impacted by mining

Proposals for Improvement of the Italian Roundabout Geometric Design Standard

AbstractThe paper presents a critical review of the Australasian, EU and US roundabout geometric design standards and guidelines and identifies inconsistencies of the Italian roundabout standard which deserve improvement. As a result, recommendations for improvement of the Italian standard are proposed. These recommendations are mainly based on the concepts of design flexibility and performance based design. Indeed, rigid standards which do not really take into account safety and operational consequences of the design decisions and the need to balance opposite demands might produce undesirable outcomes

Cryopreservation of threatened native Australian species—what have we learned and where to from here?

Cryogenic storage techniques have been developed and adopted for more than 100 (mainly agricultural) plant species worldwide, and within Australia, at least 30 critically endangered plants have been stored long term using cryogenic approaches. Nevertheless, there are many species that are very difficult to store using current procedures, and organizations involved in plant germplasm conservation (such as botanic gardens, agricultural institutions, etc.) that utilise cryogenic storage techniques are in some respects at a crossroads in their endeavours to cheaply and effectively store a wide selection of species and genotypes for conservation and agricultural/horticultural purposes. For taxa that are not amenable to current cryogenic approaches, new ways of developing cryogenic storage techniques need to be investigated, including research into the ways in which cell membranes interact and change when cooled to cryogenic temperatures (−196°C in liquid nitrogen) in the presence of various cryoprotective agents. This review highlights the current state of cryogenic research both within Australia and internationally, provides a case study on threatened plant species and also describes several new research initiatives that aim to provide answers to why some native species are quite amenable to widely utilised cryogenic approaches whilst others are currently non-responsive. New approaches aim to integrate laboratory and membrane modelling paradigms to provide guidelines for the development of new cryopreservation protocols and to assess the robustness of theoretical models in predicting optimum cryogenic conditions

Coexistence in a random growth model with competition

We consider a variation of the Hastings-Levitov model HL(0) for random growth in which the growing cluster consists of two competing regions. We allow the size of successive particles to depend both on the region in which the particle is attached, and the harmonic measure carried by that region. We identify conditions under which one can ensure coexistence of both regions. In particular, we consider whether it is possible for the process giving the relative harmonic measures of the regions to converge to a non-trivial ergodic limit

A Godunov Method for Multidimensional Radiation Magnetohydrodynamics based on a variable Eddington tensor

We describe a numerical algorithm to integrate the equations of radiation magnetohydrodynamics in multidimensions using Godunov methods. This algorithm solves the radiation moment equations in the mixed frame, without invoking any diffusion-like approximations. The moment equations are closed using a variable Eddington tensor whose components are calculated from a formal solution of the transfer equation at a large number of angles using the method of short characteristics. We use a comprehensive test suite to verify the algorithm, including convergence tests of radiation-modified linear acoustic and magnetosonic waves, the structure of radiation modified shocks, and two-dimensional tests of photon bubble instability and the ablation of dense clouds by an intense radiation field. These tests cover a very wide range of regimes, including both optically thick and thin flows, and ratios of the radiation to gas pressure of at least 10^{-4} to 10^{4}. Across most of the parameter space, we find the method is accurate. However, the tests also reveal there are regimes where the method needs improvement, for example when both the radiation pressure and absorption opacity are very large. We suggest modifications to the algorithm that will improve accuracy in this case. We discuss the advantages of this method over those based on flux-limited diffusion. In particular, we find the method is not only substantially more accurate, but often no more expensive than the diffusion approximation for our intended applications.Comment: 42 pages, 22 figures, 2 tables, accepted by ApJ

Influence of the COVID-19 Pandemic on mood and training in Australian community tennis players

The COVID-19 outbreak has led to the implementation of strict restrictions in Australia, which have severely impacted sporting activities. Tennis is played by 6.2% of the population within the Oceania region, and is a valuable sport for maintaining social, mental, and physical health. Current literature indicates the COVID-19 pandemic has negatively affected the mental health of Australian residents. The aim of this study was to investigate changes in training and match play due to the outbreak, and its effects on emotional well-being of Australian senior tennis players. Additionally, explore any differences between middle aged (41-60 years) and senior (61 years and over) Australian tennis players. An online survey was used to assess training and match play habits, as well as ascertain the emotional well-being of tennis players. The survey was active from 24th April 2020 until 6th June 2020. Participants were adult (41+ years) tennis players from Australia. Wilcoxon signed rank tests were performed to check for differences in training hours and tennis matches played. Mann-Whitney tests were used to assess the difference in Brief Emotional Experience Scale (BEES) scores, employment status as well as the training hours and tennis matches played between the two age groups. A Kendall\u27s Tau B correlation test was performed to assess the associations of training, match play and demographic characteristics with BEES scores. Kruskal-Wallis tests assessed differences in BEES scores between participants of differing match play formats, tennis experience and cessation of tennis training time periods. There were 245 respondents who met our inclusion criteria. Tennis training hours along with the tennis matches played significantly decreased during COVID-19 compared to pre-COVID-19, 85.09 and 88.48%, respectively. No significant ( \u3e 0.05) differences were observed between age groups for any of the training modality hours, nor was there any significant difference in number of tennis matches played. The participants average BEES score was 0.99 ± 1.27, indicating that respondents had a positive emotional well-being during the COVID-19 pandemic. The emotional well-being of the senior group was significantly ( = 0.002) higher than the middle aged group. Together, our results show that training and tennis match play decreased during the COVID-19 pandemic, however the emotional well-being of senior tennis players in Australia appeared to not be negatively affected

Liberation Psychology as an Agent of Change for First Nations Peoples: An Exploration of the Decolonisation of Concepts to Minimise Miscommunications and Assumptions in an Australian Context

This thesis is about decolonisation and empowerment. It is specifically about First Nations people claiming or reclaiming their autonomy. This thesis explores concepts, in this case a focus on the term 'resilience', to address miscommunications and to perhaps minimise mistakes that can be made due to assumed knowledge; assumed congruence of terms and concepts. The history of psychology as a discipline is discussed, along with its role in the oppression of First Nations people worldwide, and in Australia. The importance of worldviews, and how miscommunications can affect healthcare, is critical for health professionals to understand. The discipline of psychology needs to ensure that it is not limiting its worldview by being too insular; it needs to be reflexive enough to both recognise its part in the history of oppression, and to become an agent of change for those who have been oppressed. Indigenous voices need to be heard as part of this reflexive psychology

Sustained Magnetorotational Turbulence in Local Simulations of Stratified Disks with Zero Net Magnetic Flux

We examine the effects of density stratification on magnetohydrodynamic turbulence driven by the magnetorotational instability in local simulations that adopt the shearing box approximation. Our primary result is that, even in the absence of explicit dissipation, the addition of vertical gravity leads to convergence in the turbulent energy densities and stresses as the resolution increases, contrary to results for zero net flux, unstratified boxes. The ratio of total stress to midplane pressure has a mean of ~0.01, although there can be significant fluctuations on long (>~50 orbit) timescales. We find that the time averaged stresses are largely insensitive to both the radial or vertical aspect ratio of our simulation domain. For simulations with explicit dissipation, we find that stratification extends the range of Reynolds and magnetic Prandtl numbers for which turbulence is sustained. Confirming the results of previous studies, we find oscillations in the large scale toroidal field with periods of ~10 orbits and describe the dynamo process that underlies these cycles.Comment: 13 pages, 18 figures, submitted to Ap

A survey to evaluate the association of COVID-19 restrictions on perceived mood and coping in Australian community level athletes

Australian community level athletes faced unprecedented changes to their training andcompetition options as the global COVID-19 pandemic took a stronghold. This disruptionwas predicted to have a negative impact on emotional well-being as communitiesbraced through periods of social isolation and physical distancing requirements. Thisstudy provides an Australian perspective on the emotional well-being of communitylevel athletes and the extent to which they coped during the COVID-19 pandemic.Emotional well-being and coping were measured using the Brief Emotional ExperienceScale and the 28-item Brief Cope Scale. Both instruments were administered alongwith other questions pertaining to participant demographics and training status via anonline survey between April and June 2020. The survey was disseminated to communityathletes through word-of-mouth and social media platforms. No significant differencesin emotional well-being were observed between athlete groups as a result of COVID-19and its associated restrictions. Coping scores also appeared to be preserved in Australiancommunity athletes, which contrasts the impact expected asa result of the COVID-19pandemic. While tentative, the observed preservation in coping may have bufferedpotential declines in emotional well-being, which has beendocumented in professionaland semi-professional athletes and the general population. These unexpected findingsand tentative suppositions warrant further investigationand highlight the importance ofconducting a country- or region-specific approach to examining the impact of COVID-19on community athletes, as responses to COVID-19 are undoubtedly not consistentthroughout the world