61871 research outputs found
Sort by
Assessing the potential for crop albedo enhancement in reducing heatwave frequency, duration, and intensity under future climate change
Get PDFAdapting to the impacts of future warming, and in particular the impacts of heatwaves, is an increasingly important challenge. One proposed strategy is land-surface radiation management via crop albedo enhancement. This has been argued to be an effective method of reducing daily hot temperature extremes regionally. However, the influence of crop albedo enhancement on heatwave events, which last three or more days, is yet to be explored and this remains an important knowledge gap. Using a fully coupled earth system model with 10 ensemble members, we show that crop albedo enhancement by up to ＋0.1 reduces the frequency of heatwave days over Europe and North America by 10 to 20 days; with a larger reduction over Europe under a future climate driven by SSP2-4.5. The average temperature anomaly during heatwaves (the magnitude of the event), is reduced by 0.8 °C to 1.2 °C where the albedo was enhanced, but reductions in mean heatwave duration are limited. There was a marked reduction in the mean annual cumulative heatwave intensity across most of Eurasia and North America, ranging from 32 °C to as high as 80 °C in parts of southern Europe. These changes were largely driven by a reduction in net radiation, decreasing the sensible heat flux, which reduces the maximum temperature, and therefore, heatwave frequency and intensity. These changes were largely localised to where the albedo enhancement was applied with no significant changes in atmospheric circulation or precipitation, which presents advantages for implementation. While our albedo perturbation of up to ＋0.1 is large and represents the likely upper limit of what is possible with more reflective crops, and we assume that more reflective crops are grown everywhere and instantly, these results provide useful guidance to policy makers and farmers on the maximum possible benefits of using more reflective crops in limiting the impacts of heatwaves under future climate
Multimodal correlative imaging and modelling of phosphorus uptake from soil by hyphae of mycorrhizal fungi
Get PDFPhosphorus (P) is essential for plant growth. Arbuscular mycorrhizal fungi (AMF) aid its uptake by acquiring P from sources distant from roots in return for carbon. Little is known about how AMF colonise soil pore-space, and models of AMF-enhanced P-uptake are poorly validated.
We used synchrotron X-ray computed tomography to visualize mycorrhizas in soil and synchrotron X-ray fluorescence/X-ray absorption near edge structure (XRF/XANES) elemental mapping for P, sulphur (S) and aluminium (Al) in combination with modelling.
We found that AMF inoculation had a suppressive effect on colonisation by other soil fungi and identified differences in structure and growth rate between hyphae of AMF and nonmycorrhizal fungi. Our results showed that AMF co-locate with areas of high P and low Al, and preferentially associate with organic-type P species over Al-rich inorganic P.
We discovered that AMF avoid Al-rich areas as a source of P. Sulphur-rich regions were found to be correlated with higher hyphal density and an increased organic-associated P-pool, whilst oxidized S-species were found close to AMF hyphae. Increased S oxidation close to AMF suggested the observed changes were microbiome-related. Our experimentally-validated model led to an estimate of P-uptake by AMF hyphae that is an order of magnitude lower than rates previously estimated – a result with significant implications for the modelling of plant–soil–AMF interactions
COVID-19 announcements and investor reactions on the Australian Securities Exchange
Get PDFThe extraordinary situation due to COVID-19 pandemic has created an opportunity to examine the behavioural patterns of investors by way of the level of trading activities on the Australian Securities Exchange (ASX) around the releases of crucial information regarding the COVID-19 pandemic. This study aims to identify abnormal trading volume at ASX around eight selected significant announcements and measures of the COVID-19 pandemic in Australia. The study finds sufficient evidence to indicate that the COVID-19 announcements and calculations influence investor decisions on the ASX as the pandemic evolved
A three-chamber electrochemical cell facilitated biogas upgrading and high-purity oxygen production
No full textAnion exchange membrane (AEM)-equipped electrochemical cells can be used for removing the carbon dioxide (CO2) from biogas, thereby upgrading its energy content. The CO2 absorbed in the catholyte can be transported across the AEM as (bi)carbonate and then recovered in the anodic chamber of the electrochemical cell. However, CO2 regeneration in the anode chamber diminishes the oxygen (O2) content in the anodic gas stream. Given this electrochemically produced oxygen can have a high-industrial application value, such as for promoting more efficient biological wastewater treatment processes, we hereby proposed and validated a three-chamber electrochemical cell configuration capable of removing CO2 and recovering it in an intermediate chamber, with a concomitant anodic generation of high-purity O2 gas. Our prototype successfully facilitated CO2 recovery in a separate chamber preventing CO2 contamination of the anodic O2 gas stream. Results also suggested that an approximately tenfold increase in CO2 loading rate enhanced the relative CO2 diffusion flux from 5 to 43% through the AEM, by lowering the catholyte pH as well as improving gas–liquid CO2 transfer. A mathematical model was also developed to accurately predict the polarization performance of the electrochemical cell
Ecology of ticks and microbes in Australian wildlife
Get PDFTicks (Ixodida) represent one of the most important vector groups affecting human and animal health, and in recent years there have been increasing concerns regarding the cause of tick-borne disease affecting Australians. Worldwide, wildlife health surveillance is recognised as a key tool for investigating tick-borne infections and a One Health approach is essential to understand the epidemiology of tick-associated microbes. Therefore, this research aimed to; i) identify ticks from Australian wildlife; ii) investigate bacteria and haemoprotozoa present in wildlife and ticks; and iii) characterise microbes and understand the interplay between host-microbetick. Molecular tools were used to assist in the identification of Australian ticks. Museum specimens of the human biting tick Amblyomma triguttatum were used to investigate the molecular systematics of this species complex. A set of molecular barcodes was developed for Australian ticks, which was important for the accurate identification of immature life stages and cryptic species. Additionally, a novel 12S rDNA metabarcoding assay was developed for high throughput identification of ticks. Free-ranging animals and their ticks were sampled from urban and periurban areas. The bacterial and haemoprotozoan diversity was characterised using a combination of amplicon high-throughput sequencing, targeted Sanger sequencing, and microscopy. Bacterial profiling generated over 100 million sequences. Statistical analysis using constrained ordination methods revealed blood, tick and tissues had distinct community signatures. A diverse range of tick associated microbes was identified, such as Anaplasmataceae, Bartonellaceae, Borreliaceae, Coxiellaceae, Midichloriaceae. Overall, these microbes were rare in wildlife hosts and generally confined to specific sample types. In addition, eight species of haemoprotozoa were identified, including species within the genera Babesia, Hepatozoon, Theileria and Trypanosoma. Lastly, this study further confirmed the absence of northern hemisphere tick-borne pathogens and provided further evidence of the unique microbes present in Australian wildlife and ticks
Exploring social media use by local tourism providers in rural Western Australia
Get PDFSocial media has had a significant impact on the tourism industry. Instagram has become a popular platform to share travel experiences due to the visual experience it offers users. This study utilised a case study approach to explore how small business, local tourism providers in the Shire of Collie, Western Australia (Collie), are using social media to promote their business and the destination. This study also examined how local tourism providers and social media users utilise hashtags on Instagram to represent a rural Western Australia tourist destination.
The study included conducting semi-structured interviews with 11 local tourism providers representing five major requirements of a tourist destination (Dickman, 1989). Common barriers in using social media were identified. Challenges included inadequate time, difficulty in measuring the impact of social media and lack of knowledge using affordances, such as using functionalities effectively. Participants shared benefits of using social media, which included reaching a wider audience and a ‘younger’ demographic. The interviews also explored influences on local tourism providers’ social media use, including the influence of destination management organisations (DMO) activities and resources.
A content analysis of hashtags on Instagram was undertaken to explore how hashtags are used in conjunction with Collie, including the most popular hashtags. Based on purposive sampling, ten hashtags related to tourism in Collie were selected. The hashtags included popular tourist attractions, such as #blackdiamondlake, and hashtags used on the Collie Visitor Centre Instagram page, including #collierivervalley and #colliewa. From this sample, five hashtags with the highest growth were used as the basis of exploration of other hashtags used in conjunction with the topic. The hashtags were categorised based on the level of DMO, to explore the influence of DMO marketing on hashtag use. Hashtags relating to Tourism Western Australia marketing campaigns such as #wanderoutyonder and #thisiswa, were amongst the most used hashtags.
Finally, this study explored Kavaratzis’ (2004) theoretical framework for developing city brands and proposes changes to the model, to include local tourism providers and social media. The framework discusses three levels of communication representing different aspects of marketing a destination: primary, secondary, and tertiary. The study proposes changes to Kavaratzis’ (2004) framework, to reflect how communication has evolved to include social media and demonstrate how it can be used to describe communication in rural tourist destinations.
This study provides a holistic approach to understanding how local tourism providers in a rural destination use social media, and may be utilised in other rural settings to develop destination image. The findings reflect that local tourism providers in Collie recognise the benefits of using social media for promotion, although there are barriers when using social media
Systematic characterization of biocrude and aqueous phase from hydrothermal carbonization of algal biomass
No full textThis contribution evaluates the impacts of reaction conditions on the yields and properties of biocrude and aqueous phase from hydrothermal carbonization (HTC) of Chlorella vulgaris (solid loading: 10.0 wt%) at 180 – 220 °C for 15 and 60 min. The results indicate that increasing HTC temperature (THTC) from 180 to 220 °C enhances biocrude yield from 8.8 to 34.6 wt%, for the holding time (th) of 60 min, and from 4.9 to 26.0 wt% for 15 min. The carbon recovery and higher heating value (HHV) of biocrude elevate with increasing both THTC and th, with the highest values of 50.6% and 34.0 MJ/kg, respectively, observed at 220 °C and 60 min. Among inorganic species, Na, Fe, and Zn display reasonable retentions in the biocrude with a pronounced effect of THTC observed at 15 min. The yield of aqueous phase increases first when THTC rises from 180 to 200 °C but decreases with further increasing THTC to 220 °C due to the re-polymerization of water-soluble organics into biocrude and/or the formation of gaseous products. The aqueous phase experiences a reduction of total organic carbon with increasing reaction severity because of the transfer of carbon to biocrude and/or gases. The aqueous phase is rich in organic nitrogen, dihydrogen phosphate, acetate, and potassium, which are required for its recycling as cultivation media. The concentrations of heavy metals (Fe, Cr, Mn, Co, Ni and Zn) in the aqueous phase are all below 9 mg/kg under the studied HTC conditions
Research priorities for the ghost bat (Macroderma gigas) in the Pilbara region of Western Australia
No full textThe ghost bat (Macroderma gigas) is Australia’s largest echolocating bat. It is restricted to several disjunct populations in the north of the continent, including a population in the Pilbara region of Western Australia. In 2016 the ghost bat was listed as Vulnerable under Australian federal legislation, owing to declining numbers across many regional populations. The most severe threat to ghost bats in the Pilbara region is the destruction and disturbance of habitat due to mining operations, but disturbance to their roosts from other infrastructure developments and changes to and loss of foraging habitat also pose significant threats. A set of research priorities for ghost bats in the Pilbara was developed during a workshop attended by mining industry representatives, environmental consultants, scientists and government regulators. Five research priorities were identified: (1) identify and characterise critical diurnal roosts and foraging habitat; (2) improve knowledge of the distribution, movement and dispersal patterns of ghost bats in the region; (3) improve knowledge of population size, persistence and long-term trends; (4) better understand the cumulative, direct and indirect impacts of mining and other development activities; and (5) better understand the threats posed by fence entanglements, cane toads and feral cats
Integration of phase change materials in improving the performance of heating, cooling, and clean energy storage systems: An overview
No full textPhase change materials (PCMs) have garnered significant attention as low-cost thermal energy storage systems that efficiently capture and store solar energy. Recent review works have largely focused only on thermal conductivity enhancement techniques, and/or applications of PCMs, while others have mainly discussed the performance enhancement of either heating, cooling, or clean energy storage systems integrating with PCMs. However, not enough studies recently reviewed all of these techniques/systems comprehensively to provide insights into them. This paper thus comprehensively reviews the integration of PCMs as an enhancement to most types of heating, cooling, and clean energy storage system performance, and the techniques to enhance thermal conductivity. The integration of PCMs with these systems has shown promising performance. For instance, an improvement of 13.5% is found in the efficiency of photovoltaic (PV) system when it is integrated with PCM/Al2O3 nanoparticles. In addition, the solar air heater's daily energy efficiency reaches 17% on its own, but when combined with PCM, it reaches 33%. However, the major drawback of using PCM–TES (thermal energy storage) for cooling is that PCM does not entirely solidify at night. The literature also shows that the issues related to PCMs' low thermal conductivity, phase separation, and subcooling/supercooling, their poor compatibility with other materials, and the environmental hazards they pose hinder their application on a large scale. It is necessary to implement international standards for assessing the thermophysical properties of PCMs and compile data to better facilitate the utilization of PCMs by end-users
Meta-QTLs for multiple disease resistance involving three rusts in common wheat (Triticum aestivum L.)
No full textRust diseases in wheat are a major threat to global food security. Therefore, development of multiple disease-resistant cultivars (resistant to all three rusts) is a major goal in all wheat breeding programs worldwide. In the present study, meta-QTLs and candidate genes for multiple disease resistance (MDR) involving all three rusts were identified using 152 individual QTL mapping studies for resistance to leaf rust (LR), stem rust (SR), and yellow rust (YR). From these 152 studies, a total of 1,146 QTLs for resistance to three rusts were retrieved, which included 368 QTLs for LR, 291 QTLs for SR, and 487 QTLs for YR. Of these 1,146 QTLs, only 718 QTLs could be projected onto the consensus map saturated with 2, 34,619 markers. Meta-analysis of the projected QTLs resulted in the identification of 86 MQTLs, which included 71 MDR-MQTLs. Ten of these MDR-MQTLs were referred to as the ‘Breeders’ MQTLs’. Seventy-eight of the 86 MQTLs could also be anchored to the physical map of the wheat genome, and 54 MQTLs were validated by marker-trait associations identified during earlier genome-wide association studies. Twenty MQTLs (including 17 MDR-MQTLs) identified in the present study were co-localized with 44 known R genes. In silico expression analysis allowed identification of several differentially expressed candidate genes (DECGs) encoding proteins carrying different domains including the following: NBS-LRR, WRKY domains, F-box domains, sugar transporters, transferases, etc. The introgression of these MDR loci into high-yielding cultivars should prove useful for developing high yielding cultivars with resistance to all the three rusts