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Mitigating impacts of climate change on flow regimes through management of small dams and abstractions
Get PDFUnregulated ‘free-flowing’ streams are essential in maintaining the ecological health of river systems within basins that are increasingly regulated by large dams. However, flow regimes in ‘free-flowing’ streams can nonetheless be impacted by smaller distributed (diffuse) forms of regulation such as small dams and pumped extractions, and climate change is expected to exacerbate these impacts. Research into these diffuse sources of regulation is rare. This study examines the relative impacts of climate change, small dams, and small extractions on streamflow. We assess whether active management of small dams and small extractions represents a potential option for mitigating reductions in flow due to climate change. Monthly rainfall-runoff models were used to characterise baseline (without human impact) flow regimes for sites across Victoria, Australia. From this baseline, the effects of climate change, small dams, and small extractions were simulated and systematically compared in various scenario combinations. We found that the projected impact of climate change far exceeded the impacts of consumptive use across most of the region during higher flow months. During lower flow months, however, the relative impacts of climate change were more significant. Importantly, our analysis shows that these impacts can be at least partly mitigated by managing the flow regime impacts of small dams and abstractions in many locations. Our approach thus not only identifies streams ‘at risk’ from climate change but also streams where mitigation options exist. These findings are likely to be broadly similar in other areas with seasonal flow regimes where the future is expected to be drier. Managing small dams and extractions in this way will require shifts in current water policy and management, noting that further research will be needed in ’at risk’ waterways to more fully understand the risks as well as potential costs and benefits of this management approach at a local scale.Full Tex
Humans in Africa's wet tropical forests 150 thousand years ago
Get PDFHumans emerged across Africa shortly before 300 thousand years ago (ka)1,2,3. Although this pan-African evolutionary process implicates diverse environments in the human story, the role of tropical forests remains poorly understood. Here we report a clear association between late Middle Pleistocene material culture and a wet tropical forest in southern Côte d’Ivoire, a region of present-day rainforest. Twinned optically stimulated luminescence and electron spin resonance dating methods constrain the onset of human occupations at Bété I to around 150 ka, linking them with Homo sapiens. Plant wax biomarker, stable isotope, phytolith and pollen analyses of associated sediments all point to a wet forest environment. The results represent the oldest yet known clear association between humans and this habitat type. The secure attribution of stone tool assemblages with the wet forest environment demonstrates that Africa’s forests were not a major ecological barrier for H. sapiens as early as around 150 ka.Full Tex
Description of the glochidia of Lortiella rugata (Sowerby, 1868) (Bivalvia: Unionida: Hyriidae) from tropical northern Australia
No full textLarvae (glochidia) of the freshwater mussel, Lortiella rugata, were obtained from marsupia of live females, preserved in ethanol and photographed under scanning electron microscopy. Glochidial shells of L. rugata are subtriangular and scalene in shape outline with a smooth surface dotted with pores and have a protruding ventral apex. Glochidial shells (n = 29) measured 256.4 μm long (L) (±1.6 SE), 230.0 μm high (H) (±1.5 SE), with a Size (mean of L and H) of 243.2 μm (±1.3 SE), hinge length (Hg) of 187.2 μm (±2.0 SE), larval hook length (LHL) of 54.8 μm (±1.2 SE) and angle of obliquity (Á) of 10.9° (±0.3 SE). Hooks are singular in each valve, lack microstylets, have convex or concave basal protuberances on opposing valves and terminate in a singular sharp cusp on each valve. In comparison to Lortiella froggatti, L. rugata has glochidia with similar in size and shape. Glochidia of L. rugata are released as amorphous mucous conglutinates and individuals possess a larval thread, characteristics typical of most Velesunioninae.Full Tex
A Technique to Integrate a Simultaneous Tooth- and Bone-Supported Surgical Guide for Lateral Sinus Lift and Precision Corticotomy
Get PDFBackground/Objectives: Surgical guides have been used in a variety of dental procedures, such as implant placement to improve clinical accuracy and reduce post-operative complications. This report presents a novel and versatile workflow for the design and fabrication of a “multi-purpose” fully-guided tooth- and bone-supported one-piece surgical guide. Methods: Briefly, intraoral and perioral anatomical features were captured by an intraoral scan and a cone-beam computed tomography scan. The data were segmented and aligned with analysis software to enable the digital design of surgical guides. The versatility of this method was demonstrated through its application in the two cases presented: the first involved a lateral sinus lift with simultaneous implant placement, and the second involved the removal of a foreign object from the alveolar bone prior to implant placement. Results: Positive clinical outcomes were confirmed at follow-up visits for up to 12 months. Conclusions: This method may be applied to a range of challenging clinical scenarios, such as apicectomy, the extraction of supernumerary or unerupted teeth, corticotomy to facilitate orthodontic movement, the precise reduction of bony spurs or exostoses, and the conservative surgical removal of pathologies.Full Tex
Is Adventure Tourism Therapeutic?
No full textCould adventure tourism be used as a mental health therapy? And if so, then how, when, for whom, and with what economic value? Mackenzie et al. (2021) argued that sport adventure tourism can provide wellbeing. Here I expand their framework and recommendations.No Full Tex
An exploratory survey assessing the determinants of heat stress and heat strain in the Canadian mining industry from the worker's perspective
No full textWith mines extending deeper and rising surface temperatures, workers are exposed to hotter environments. This study aimed to characterize heat stress and strain in the Canadian mining industry and evaluate the utility of the Heat Strain Score Index (HSSI), combined with additional self-reported adverse health outcomes. An exploratory web-based survey was conducted among workers (n = 119) in the Canadian mining industry. The survey included 74 questions on workers’ risk perception, strategies for heat stress management, and the HSSI—a validated tool to classify workplace heat stress based on various workplace factors and indicators of heat strain. Most workers reported that heat stress is an occupational hazard associated with their duties and tasks (89%). Based on the HSSI, 22% of respondents were classified as high risk, 42% at moderate risk, and 36% at low risk for heat stress and heat strain. Those with higher HSSI scores self-reported more heat-related adverse signs and symptoms with a higher prevalence of self-reported heat-related illness (p < 0.01). Despite workers reporting various self-initiated practices (e.g., drinking water) and management-enforced heat mitigation practices (e.g., rest breaks), many workers reported still having experienced signs or symptoms of heat stress (86%) and heat-related illnesses (37%). The study found elevated heat stress and strain levels among a sample of workers in the Canadian mining industry despite workers employing various heat-mitigating strategies. Heat stress management programs considering mining-specific factors and challenges are needed to safeguard worker health and safety.No Full Tex
Twelfth scientific biennial meeting of the Australasian Virology Society: AVS12 2024
Get PDFThe Australasian Virology Society (AVS) holds premier biennial virology meetings that foster multidisciplinary research and collaboration and promote equity and inclusion of early-career researchers. The 12th AVS meeting (AVS12), convened by M. Tate, J. Fraser, and G. Moseley, was held from 2 to 5 December 2024 on Dja Dja Wurrung country at the RACV Goldfields Resort in Creswick, Victoria, Australia. In this report, we give a brief overview of the history of AVS and outline the current and developing priorities for the society. We provide a summary of the insightful panel discussions held to address career development and Indigenous virology, highlight the presentations given by international plenary speakers Joe Grove and Chantal Abergel, and celebrate the recipients of the numerous awards.Full Tex
An investigation of the practices of middle leaders in Australian schools
Get PDFThe role of middle leaders in Australian schools as influencers on classroom practice has been the focus of increased attention in recent years. Although there is recognition of the importance of middle leaders, there are gaps in what we understand about their practices and the nuances of practice that occur due to site-based conditions, or practice architectures, within each individual school context. This paper explores the self-reported practices of 25 middle leaders from a range of primary and secondary schools across Australia to deepen our understanding of how those practices are played out and how best to support the development of middle leaders. Analysis of data from in-depth interviews revealed the need to provide resources, conditions, and arrangements that are focused on what happens in classrooms, along with professional learning that is individualised and contextualised to assist the transition from teacher to leader of teaching and learning. Further, middle leaders require support from senior leaders that recognises the complex and hectic nature of middle leading.Full Tex
Detecting and Corrupting Convolution-based Unlearnable Examples
Get PDFConvolution-based unlearnable examples (UEs) employ class-wise multiplicative convolutional noise to training samples, severely compromising model performance. This fire-new type of UEs have successfully countered all defense mechanisms against UEs. The failure of such defenses can be attributed to the absence of norm constraints on convolutional noise, leading to severe blurring of image features. To address this, we first design an Edge Pixel-based Detector (EPD) to identify convolution-based UEs. Upon detection of them, we propose the first defense scheme against convolution-based UEs, COrrupting these samples via random matrix multiplication by employing bilinear INterpolation (COIN) such that disrupting the distribution of class-wise multiplicative noise. To evaluate the generalization of our proposed COIN, we newly design two convolution-based UEs called VUDA and HUDA to expand the scope of convolution-based UEs. Extensive experiments demonstrate the effectiveness of detection scheme EPD and that our defense COIN outperforms 11 state-of-the-art (SOTA) defenses, achieving a significant improvement on the CIFAR and ImageNet datasets.Full Tex
Comparison of Random Forest and Stepwise Regression for Variable Selection Using Low Prevalence Predictors: A case Study in Paediatric Sepsis
Get PDFIntroduction
Variable selection is a common technique to identify the most predictive variables from a pool of candidate predictors. Low prevalence predictors (LPPs) are frequently found in clinical data, yet few studies have explored their impact on model performance during variable selection. This study compared the Random Forest (RF) algorithm and stepwise regression (SWR) for variable selection using data from a paediatric sepsis screening tool, where 18 out of 32 predictors had a prevalence < 10%.
Methods
Variable selection using RF was compared to forward and backward SWR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), and the variables retained. Additionally, a simulation study assessed how increasing the prevalence of the predictors impacted the variable selection results.
Results
The best fitting RF and SWR models retained were 22, and 17 predictors, respectively, with 14 and 10 predictors having a prevalence < 10%. Both the RF and SWR models had similar predictive performance (RF: AUC [95% Confidence Interval] 0.79 [0.77, 0.81], LR: 0.80 [0.78, 0.82]). The simulation study revealed differences for both RF and SWR models in variable importance rankings and predictor selection with increasing prevalence thresholds, particularly for moderately and strongly associated predictors.
Discussion
The RF algorithm retained a number of very low prevalence predictors compared to SWR. However, the predictive performance of both models were comparable, demonstrating that when applied correctly and the number of candidate predictors is small, both methods are suitable for variable selection when using low prevalence predictors.Full Tex