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Predicting the dispersal of SARS-CoV-2 RNA from the wastewater treatment plant to the coast
Get PDFViral pathogens including SARS-CoV-2 RNA have been detected in wastewater treatment effluent, and untreated sewage overflows, that pose an exposure hazard to humans. We assessed whether SARS-CoV-2 RNA was likely to have been present in detectable quantities in UK rivers and estuaries during the first wave of the Covid-19 pandemic. We simulated realistic viral concentrations parameterised on the Camel and Conwy catchments (UK) and their populations, showing detectable SARS-CoV-2 RNA concentrations for untreated but not for treated loading, but also being contingent on viral decay, hydrology, catchment type/shape, and location. Under mean or low river flow conditions, viral RNA concentrated within the estuaries allowing for viral build-up and caused a lag by up to several weeks between the peak in community infections and the viral peak in the environment. There was an increased hazard posed by SARS-CoV-2 RNA with a T90 decay rate >24 h, as the estuarine build-up effect increased. High discharge events transported the viral RNA downstream and offshore, increasing the exposure risk to coastal bathing waters and shellfisheries – although dilution in this case reduced viral concentrations well below detectable levels. Our results highlight the sensitivity of exposure to viral pathogens downstream of wastewater treatment, across a range of viral loadings and catchment characteristics – with implications to environmental surveillance
Understanding the Relationship Between Age-Related Hearing Loss and Alzheimer’s Disease: A Narrative Review
Get PDFEvidence suggests that hearing loss (HL), even at mild levels, increases the long-term risk of cognitive decline and incident dementia. Hearing loss is one of the modifiable risk factors for dementia, with approximately 4 million of the 50 million cases of dementia worldwide possibly attributed to untreated HL. This paper describes four possible mechanisms that have been suggested for the relationship between age-related hearing loss (ARHL) and Alzheimer’s disease (AD), which is the most common form of dementia. The first mechanism suggests mitochondrial dysfunction and altered signal pathways due to aging as a possible link between ARHL and AD. The second mechanism proposes that sensory degradation in hearing impaired people could explain the relationship between ARHL and AD. The occupation of cognitive resource (third) mechanism indicates that the association between ARHL and AD is a result of increased cognitive processing that is required to compensate for the degraded sensory input. The fourth mechanism is an expansion of the third mechanism, i.e., the function and structure interaction involves both cognitive resource occupation (neural activity) and AD pathology as the link between ARHL and AD. Exploring the specific mechanisms that provide the link between ARHL and AD has the potential to lead to innovative ideas for the diagnosis, prevention, and/or treatment of AD. This paper also provides insight into the current evidence for the use of hearing treatments as a possible treatment/prevention for AD, and if auditory assessments could provide an avenue for early detection of cognitive impairment associated with AD
Serotinous forest resilience in a warmer and more fire-prone world
Get PDFWarming climate and increased fire activity are expected to lead to decreased capacity of woody plant-dominated ecosystems to recover following fire (i.e., the erosion of resilience) in ecosystems globally. Systems characterized by stand-replacing fire regimes and dominated by serotinous plants (plants that release seeds from cones when heated by fire) may be particularly at risk. Two key conditions for resilience to fire in systems dominated by serotinous species are the sufficient production of cones following one fire and prior to the occurrence of subsequent stand-replacing fire (reburn) and climate conditions suitable for recruitment in the first post-fire year. Expected increases in fire frequency, hot and dry conditions during the inter-fire period, and occurrence of post-fire drought may lead to significant decreases in serotinous plant population persistence (interval squeeze). While the interval squeeze has been demonstrated for some serotinous species (e.g., Banksia spp. in Western Australia), key knowledge gaps exist regarding these resilience mechanisms in North American forests and how populations may respond in a warmer future with more fire.
My thesis used closed-cone pine (Pinus attenuata and P. muricata) forests of California, USA as a study system to empirically test for evidence of the interval squeeze. Specifically, I assessed the developmental trajectories of fuels and cones over a chronosequence of three decades since stand-replacing fire to understand how reburn and population self-replacement potential develop over time. Building on these trajectories, I assessed the effects of fire interval and post-fire climate on in situ post-fire recruitment within the first two years post-fire, using a plot network of stands that burned in 2018, on intervals from 6 - 31 years. Further, for these sample fires, I used remotely sensed burn severity data to understand how time since fire and prior burn severity affected reburn probability. I found that 1) fuel development occurs rapidly in these forests, with fuels available to support a high severity reburn by ~10 years post-fire 2) canopy seedbank development to support stand self-replacement occurs by ~15 years post-fire, 3) in situ post-fire recruitment was present following all fire intervals, and reaches stand self-replacement for fire intervals ≥15 years on average, but under harsh post-fire climate conditions, fire intervals must be ≥20 years to reach stand self-replacement. Collectively, these results suggest that closed-cone pine forests are resilient to relatively frequent stand-replacing fires and warming that has occurred in the early 21st century. However, if fire recurs on an interval of <15 years, or post-fire growing seasons co-occur with severe drought conditions, resilience may be eroded. Combined with a review of the literature on the environmental conditions that have given rise to serotiny as a trait and variability in trait expression, this work provides a framework for understanding how coniferous forests dominated by serotinous species may respond to future climate and changing fire activity in ecosystems across North America, with significant implications for forest and fire management in rapidly changing environmental conditions
Disrupting assumptions about the shift to online teaching and learning in universities: Diverse student perceptions and attributions
No full textAustralian universities, and their students, continue to navigate shifts to online teaching and learning, accompanying the COVID-19 pandemic. This presentation explores the importance of questioning and disrupting assumptions about this shifting landscape, from the perspective of diverse students. To gain access to these perspectives, the present study facilitated a focus group with a small number of students from different study areas in one metropolitan Australian university. Framed through Lefebvre's heuristic describing inter-related spaces within a given social context, the study highlights how students construed their lived space of online teaching and learning, as well as how they perceived the practices and resourcing of their educators, and arrangements at an institutional level. Interpretive analysis through the lenses of Lefebvre's spatial frame and Gee's critical discourse analysis, suggests that students foregrounded their own diversities and learning needs, and attributed impacts in regard to time and flexibility for study, teaching and learning communications, the quality of online formats, availability of opportunities to participate in different ways of knowing, and educator workload. With the caveat that the study comprised a small pilot, early findings appear to disrupt the accepted premise that students prioritise socio-relational aspects of teaching and learning, with implications for future designs
Communities of practice with a difference: Collaborative academic writing during disruption
No full textAcademic writing has been difficult to prioritise over the past three years due to the increased disruption of COVID-19. Workload pressures of early career researchers and higher degree research students within the Education discipline have increased. Prioritising academic writing, along with the need to create new writing opportunities led to a small but focused group of committed participants to create a communities of practice approach to academic writing. In this presentation, we share early findings from our collaborative approach, including key success factors for higher research degree students and academic writers seeking to establish a collaborative writing practice. The importance of the community in supporting and nurturing members to become more productive has been a key result as each participant held different expectations and pursued personally significant outcomes
Noticing soil in early childhood: Cultivating the arts of attention in the anthropocene
No full textSoil is crucial for earthly ongoingness, yet it is frequently overlooked or ignored by humans. This presentation will share early insights from a participatory research project exploring child-soil relations in Perth, Western Australia that is informed by the philosophy and practices of the educational project of Reggio Emilia. The study seeks to cultivate attentiveness to soil through aesthetic and speculative encounters where soil becomes an ecological imaginary for attuning to the inextricable connectedness of the world. The project is grounded in the idea that if we are to care for soil we need first need to notice it. It is hoped insights from this research will help to nourish pedagogical terrains for children and teachers in troubled times
Which key factors explain a country's mathematics performance in PISA?
No full textSince 2000, the Programme for International Student Assessment (PISA) has directly and indirectly led to educational reforms and policy changes in many countries. PISA 2022 will focus on mathematics, with 38 OECD (Organisation for Economic Co-operation and Development) countries and probably over 50 non-members participating in this cycle. With the increased attention being paid to PISA results, extensive research has been conducted to investigate which factors contribute to high PISA math performance. This presentation will present the first comprehensive, systematic literature review on the factors that shape PISA math performance. Informed by an extensive understanding of these factors, the presenter will then utilise qualitative comparative analysis (QCA), an innovative method in education research, to further analyse the driver of high performance. Using the most recent math scores available from 65 countries, I will introduce my research design, share some preliminary results, and discuss pathways for further research
Near-infrared-shielding energy-saving borosilicate glass-ceramic window materials based on doping of defective tantalum tungsten oxide (Ta0.3W0.7O2.85) nanocrystals
Get PDFNIR-shielding window materials were fabricated by direct embedding of Ta0.3W0.7O2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H2WO4 and Ta2O5 in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H2WO4 and 0.3 mol% Ta2O5 exhibited high visible light transmittance 74.4% and strong NIR-shielding ability ΔT = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta0.3W0.7O2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta0.3W0.7O2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance
Biomarkers of coagulation and inflammation in dogs after randomized administration of 6% hydroxyethyl starch 130/0.4 or Hartmann’s solution
Get PDFSynthetic colloid fluids containing hydroxyethyl starch (HES) have been associated with impairment of coagulation in dogs. It is unknown if HES causes coagulation impairment in dogs with naturally occurring critical illness. This study used banked plasma samples from a blinded, randomized clinical trial comparing HES and balanced isotonic crystalloid for bolus fluid therapy in 39 critically ill dogs. Blood was collected prior to fluid administration and 6, 12, and 24 h thereafter. Coagulation biomarkers measured at each time point included prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, and the activities of coagulation factors V, VII, VIII, IX, and X, von Willebrand factor antigen, antithrombin, and protein C. Given the links between coagulation and inflammation, cytokine concentrations were also measured, including interleukins 6, 8, 10, and 18, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. Data were analyzed with linear mixed effects models. No significant treatment-by-time interactions were found for any biomarker, indicating that the pattern of change over time was not modified by treatment. Examining the main effect of time showed significant changes in several coagulation biomarkers and keratinocyte-derived chemokines. This study could not detect evidence of coagulation impairment with HES
Synthesis of electrolytic manganese dioxide (EMD) and biomass waste-derived carbon for hybrid capacitors
Get PDFRenewable energy (RE) is expected to be the primary energy supplier in the future energy mix. This has created the necessity for low-cost, safe, and reliable energy storage to guarantee a continuous energy supply by the intermittent RE sources. Due to the inbuilt rich chemistry of manganese dioxide (MnO2) and the advantageous characteristics; of low cost, environmentally friendliness, and nontoxic, it can be adapted for a wide range of applications such as biosensors, humidity sensors, catalysts, and so on. Among the different forms of MnO2, electrolytic manganese dioxide (EMD) is well-demanded energy storage material. However, the limitations such as lower capacitance, irreversibility, and cyclability of EMD in comparison with other metal oxides such as cobalt and nickel oxides, have hindered its application in capacitor energy storage, which was one of the focuses of this thesis.
Therefore, this Ph.D. research project aimed at synthesizing modified EMD materials as the positive electrode for hybrid capacitor applications. The modified EMD was coupled with the biomass-derived activated carbon (AC) which is synthesized as the negative electrode to fabricate hybrid capacitors. This Ph.D. research work has contributed to the existing knowledge through the following: 1) synthesizing pristine EMD using galvanostatic electrodeposition and studying its suitability for capacitor applications via experimental and theoretical analysis, 2) biopolymer alginate assisted EMD synthesis and optimization via experimental and computational modeling, 3) studying the effect of varying surfactants to improve the electrochemical characteristics of EMD, 4) synthesis of biomass waste-derived activated carbon and modeling their parameters for capacitance prediction.
The results indicated the challenge and importance of the delicate tailoring of the EMD characteristics for capacitor application. Pristine EMD was synthesized under different electrodeposition experiment conditions by varying applied current density (100, 200, 300 A m-2) and deposition duration (4, 5, 6 h). The electrodeposition was carried out in a low acidic medium electrolytic bath where a lead (Pb) anode and stainless steel (SS) cathode were used. The EMD was deposited on the Pb anode via Mn2+ oxidation to form Mn4+ and its oxide MnO2. The physicochemical and electrochemical characterization of the obtained EMD powder concluded that the material deposited at 200 A m-2 for 5 hours, showing the spindle-like morphology was suitable over others for supercapacitor (SC) application. The pristine EMD at these experimental conditions delivered 98 F g-1 capacitance at 1 mA cm-2 applied current density tested in 2 M NaOH aqueous electrolyte and proved its potential development by modifying its characteristics. Therefore, the pristine EMD was modified by introducing the biopolymer alginic acid crosslinking to improve its electrochemical performance. The alginic acid was added to the electrolytic bath at varying concentrations; 0, 0.1, 0.25, 0.5, and 1 g l-1, to optimize the added bio-polymer amount to maximize the capacitance. At 0.5 g l-1, the pristine EMD morphology was rearranged to a cactus-shaped with flutes. The calculated specific capacitance of the modified EMD was ~5 times higher (487 F g-1) than the pristine EMD. The molecular dynamics simulation results determined the polymer-ion interactions in the electrolytic bath and provided evidence, showing that the alginic acid could act as a template for binding the Mn2+ ions in a relatively ordered manner for the growth of the EMD deposit. 0.42 of pyrolusite and 0.58 of ramsdellite fractions present in the modified material were quantitatively determined using the neutron powder diffraction (NPD) data. The slight increments of the lattice spacing observed in high-resolution transmission electron microscopy (HRTEM) images were well aligned with the NPD results of unit cell volume expansions of the EMD-polymer composite showing the polymer intercalation within the EMD structure influencing its characteristics. At 2 mA cm-2, the fabricated hybrid capacitor delivered 52 F g-1 specific capacitance, 14 Wh g-1 specific energy, 500 W g-1 specific power, and 94 % capacitance retention over 5000 cycles. The results highlighted the importance of the functional molecular structure of the biopolymer alginic acid to produce a binary composite of EMD-polymer as a capacitor material.
Further, the pristine EMD was modified by electrodepositing the MnO2 using surfactant mediated electrolyte solutions. The electrochemical performance of the synthesized EMD in the presence of three novel cationic surfactants was compared with the pristine EMD and the EMD co-deposited with commonly used cetyltrimethylammonium ammonium bromide (C-AB) surfactant. The three surfactants with different molecular structures are Tetradecyltrimethylammonium bromide (T-AB), Didodecyldimethylammonium bromide (D-AB), Benzyldodecyldimethylammonium bromide (B-AB) used at varying concentrations (15, 30, 60 g l-1) in the electrolytic bath. Among the B-AB surfactant at 30 mg l-1, the EMD (EMD/B-AB30) showed the highest capacitance of 602 F g-1 tested at 1 mA cm-2 current density. The molecular dynamics simulation indicated that when the B-AB surfactant was attached to the Pb electrode via electrostatic, Van der Walls interactions, then the nucleation of MnO2 particles occurred surrounding the surfactant molecule. The unique molecular structure influenced the nucleation formation well-ordered, whereas, for pristine EMD, the nucleation was random. The hybrid capacitor comprises the best performed modified EMD (EMD/B-AB30), and biomass waste-derived AC exhibited 91 F g-1 specific capacitance, an outstanding energy density of 32.4 Wh kg-1 for a corresponding power density of 971 W kg-1.
Valorization of the biomass waste, Mango seed husk (MS), and the Grape marc (GM) was carried out by converting the waste into AC for capacitor electrodes. The MS was carbonized, followed by chemical activation using KOH as the activating agent. Activation temperature was varied at 800, 900, 1000, and 1100 °C temperatures, among at 1100 °C highest surface area of 1943 m2 g-1, and the specific capacitance of 135 F g-1 was obtained for the MS-AC. The MS-AC experimental data were incorporated in four machine learning (ML) algorithms; linear regression (LR), decision tree (DT), support vector regression (SVR), and multi-layer perceptron (MLP) for capacitance prediction. Among, the MLP model showed the best correlation (R2 = 0.9868) between the experimental and predicted capacitance values and proved its potential application for computing the complex non-linear relationships between the input and output datasets. Further, the porous carbon materials were derived from GM using four synthesis routes by varying the parameters of activating agent (KOH and ZnCl2), dopant (Nitrogen), and carbonization (450, 600 °C) and activation (450, 800 °C) temperatures. Among the different GM-AC products, the GM carbon, doped with urea and activated by KOH (KACurea), exhibited better morphology, hierarchical pore structure, larger surface area (1356 m2 g-1), and the highest specific capacitance of 139 F g-1 in 2 M NaOH aqueous electrolyte. The miscellaneous collection of datasets based on AC experiments was used for specific capacitance and power prediction using the MLP ML model.
Overall, this thesis showed that the EMD could be produced in bulk to be used for hybrid capacitor applications. Particularly, it provided insights about the specie interactions in the electrolyte solution that improved the material performance. This built the platform for further studies on altering the additive concentrations and combinations for developing high-performing EMD materials. This Ph.D. work also highlighted the opportunities to valorize the biomass waste to produce AC with desired characteristics of hierarchical pore structure, larger surface area, etc., to replace the conventional AC electrodes. Finally, the electrochemical performance of the hybrid capacitor fabricated using best performed EMD material (EMD/B-AB30) and biomass-waste derived AC (MS-AC 1100) surpassed the energy density values of the existing supercapacitors, proving its potential development in commercial applications