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Kinetics of antigorite dehydroxylation for CO2 sequestration
No full textHeat-treatment of serpentine minerals generates structural amorphicity and increases reactivity during subsequent mineral carbonation, a strategy for large-scale sequestration of CO2. This study employs thermal analyses (TGA-DSC) in conjunction with in-situ synchrotron powder X-ray diffraction (PXRD) to record concurrent mass loss, heat flow, and mineralogical changes during thermal treatment of antigorite. Isoconversional kinetic modelling demonstrates that thermal decomposition of antigorite is a complex multi-step reaction, with activation energies (Eα) varying between 290 and 515 kJ mol−1. We identify three intermediate phases forming during antigorite dehydroxylation, a semi-crystalline chlorite-like phase (γ-metaserpentine) showing an additional reaction pathway for the decomposition of Al2O3-rich antigorite into pyrope, and two distinct amorphous components (α and β-metaserpentine) which convert into forsterite and enstatite at higher temperature, respectively. The combination of isoconversional kinetics with in-situ synchrotron PXRD illustrates, for the first time, that local crystal structure changes, related to intermediate phase and forsterite formation, are responsible for the steep increase in activation energy above 650 °C and only 49% dehydroxylation can be achieved prior to this increase. This suggests that the high thermal stability of Al2O3-rich antigorite would severely limit Mg extraction during application of mineral carbonation under flue gas conditions
Understanding the eating quality perceptions of international consumers to Australian sheepmeat
Get PDFConsistent eating quality of sheepmeat is crucial to satisfy consumers, ensuring that they repurchase product. Therefore, this thesis explored the key factors that affect consumer perceptions of eating quality, namely American, Australian and Chinese consumers tasting Australian sheepmeat. These international consumer groups were selected based on their divergent relationships with lamb and sheepmeat products, and relevance to the Australian sheepmeat industry. To test consumer responses, the Meat Standards Australia (MSA) sensory protocols were utilised as they provide an internationally accepted methodology to assess untrained consumer perceptions of sheepmeat and beef products. Further, the existing MSA prediction models already adopted by the Australian industry provide a mechanism for the seamless integration of findings from this work.
The first experiment compared the sensory responses of 2,160 untrained American, Australian and Chinese consumers to grilled longissimus lumborum and semimembranosus muscles from Australian lambs (n=164) and yearlings (n=168). Linear mixed effects models demonstrated no difference between the three countries for juiciness and overall liking scores, while for tenderness, liking of flavour and odour, American consumers scored highest, followed by Australian and Chinese consumers. Across these consumer groups, similar factors were shown to influence eating quality, yet varied in the magnitude of their effect. All consumer groups preferred the longissimus lumborum, lambs compared to yearlings, and Merino sired and female lambs. Analysis of consumer demographic factors and sheepmeat consumption habits on eating quality scores, demonstrated consumer age, gender, number of adults in a household and income affected sensory scores, however no consistent trend was observed across the different countries. Frequency of lamb consumption had an impact on sensory scores of the three consumer groups. Linear discriminate analyses were used to determine quality thresholds, and accuracy of predicted quality grades compared to actual consumer assigned grades. Chinese consumers demonstrated the most generous consignment of samples to higher quality grades, while American and Australian consumers were similarly more critical. The optimised discriminate function was also most accurate for Chinese consumer assignment to quality grades compared to Australian and American predictions. The last component of this work aimed to develop and test a new MSA cooking method, traditional Chinese hotpot. This experiment involved testing sensory responses of 720 untrained Chinese consumers to Australian lamb (n=108) and yearling (n=109) shoulder and leg cuts to assess the impact of cut-type and animal factors on eating quality using this cooking method. Shoulder cuts were more palatable than leg cuts, lambs were preferred to yearlings, and increasing intramuscular fat had a positive influence on sensory scores. Conversely, increasing muscularity negatively influenced eating quality scores. Results suggest shoulder and leg cuts cooked using hotpot could provide a better eating experience compared to some previously tested sheepmeat cooking methods. In addition, the influence of muscularity and intramuscular fat emphasise the importance of balanced selection for quality and yield traits to ensure consumer satisfaction is maintained.
Overall, results demonstrated that consumer sensory perceptions of sheepmeat are highly consistent across countries, irrespective of cultural differences, with minimal variation in eating quality scores between the three countries and a consistent response to animal and production factors. However, the discriminate analysis demonstrated some perceptions of quality varied between the three countries, suggesting further investigation through the scope of the new sheepmeat MSA model may be beneficial to determine whether adjustments should be made to prediction models for product destined for these markets
Graphene-based catalysts for biodiesel production: Characteristics and performance
No full textBiodiesel is a promising alternative to reduce the dependency on fossil fuels. However, biodiesel's cost is still higher than its petroleum counterpart, hence its production process must be modified to make it economically viable. Microalgae are an alternative feedstock to replace agricultural crops for biodiesel production, and offer several advantages such as fast growth, use of non-arable land, growth in saline and wastewater, and high lipid yield. Unfortunately, biodiesel production from microalgae is very energy-intensive and costly, mainly due to the high energy consumption required for dewatering and drying. Therefore, utilizing wet microalgal biomass instead of dry biomass can be a promising solution to reduce the biodiesel production cost Furthermore, the use of heterogeneous catalysts offers high efficiency, recoverability, and reusability, and is therefore very promising from the economic and environmental perspectives. The unique characteristics of graphene-based nano-catalysts, such as their high surface area, two-dimensional structure, and functional groups, make them suitable candidates for biodiesel production. In this review, the use of graphene-based catalysts for biodiesel production is analyzed in depth, and their efficiency compared to other heterogeneous catalysts is scrutinized. Moreover, their recoverability, reusability, and economic feasibility are critically discussed, and their potential to produce biodiesel from wet microalgae is explored as a sustainable and cost-effective approach
‘Drone’: technically correct, popularly accepted, socially acceptable
Get PDFThe Journal of Unmanned Vehicle Systems—led by its founding editor, David Bird—published its first issue in December 2013. It was the first peer-reviewed scientific journal entirely dedicated to research relating to all types of remotely piloted or autonomous robotic vehicles, including those that operate in the air, on the ground, or on or below the water’s surface. Although rare currently, it could also expand to include those that operate in outer space environments (Potter 2020). This is a uniquely eclectic field of research that encompasses multiple engineering and design aspects of the vehicles themselves in addition to a diverse and ever-growing array of practical applications of the technology..
Avian community changes following drought-induced canopy collapse in a Mediterranean-type forest
Get PDFContext: Extreme drought can result in the widespread die-off of forests and dramatically altered ecosystem structure. Such changes are likly to influence fauna using resouces within these forests.
Aims: Following a record hot and dry year/summer in 2010/11, large-scale canopy collapse occurred within a Mediterranean-type mixed jarrah (Eucalyptus marginata)–marri (Corymbia calophylla) forest in south-west Western Australia. We investigated the effects of this collapse on bird assemblages in 2016, 5 years after the initial collapse.
Methods: We carried out bird surveys using a standardised search method for five paired drought-affected and adjacent healthy forest plots.
Key results: A total of 3042 records of 51 bird species were observed across all surveys. Overall, the pooled (mean ± s.d.) reporting rates for drought-affected plots (13.84 ± 0.60 individuals/survey) were significantly less than the reporting rates for healthy plots (34.44 ± 1.03 individuals/survey) (PERMANOVA: F1 = 54.94, R2 = 0.31, P = 0.001). Species diversity was also higher in healthy plots (t26 = 11.21, P < 0.001). Foliage-searching birds were the most abundant guild across all plots and were reported less often in drought-affected plots (t6 = 2.70, P < 0.04).
Conclusions: Drought-affected jarrah forest plots exhibited significant differences in bird assemblages compared to healthy plots. Overall, the drought-affected forest provides a less favourable habitat for birds compared to healthy forest.
Implications: With marked variability and extreme climate events predicted for the future, understanding the impacts of such changes will contribute to how we manage forest ecosystems
The pandemic and the politics of Australian research governance
No full textFollowing the 1989 unified higher education reforms, the Australian academic research system was built upon the notion of depoliticisation (i.e., keeping the political character of decision at one remove from governance) to govern the contradiction between research credibility and governmental economic priorities. The article argues that the COVID-19 pandemic exacerbated the tension between independent research and governmental economic priorities. The pandemic, also, weakened university autonomy via the closure of the national border, reducing overseas student fees, a significant source of research funding. The article maintains that the conservative Morrison government used the opportunity to politicise research around commercialisation and national sovereignty. The argument being that the pandemic exposed Australia’s research and development (R&D) dependence and with it the question of industrial sovereignty, prompting the government to couple academic research to industry policy. Secondly, the pandemic reinforced the conservative government’s aim to concentrate research in selected commercial areas and to exert this priority on to the research funding agency, the Australian Research Council (ARC). Lastly, the article contends that the COVID pandemic, originating in Wuhan, intensified the Morrison government’s geopolitical concerns over China, and this disquiet flowed into research policy, which problematised research collaboration with Chinese researchers
The 1-aminocyclopropane-1-carboxylic acid deaminase-producing Streptomyces violaceoruber UAE1 can provide protection from sudden decline syndrome on date palm
Get PDFIn the United Arab Emirates (UAE), sudden decline syndrome (SDS) is one of the major fungal diseases caused by Fusarium solani affecting date palm plantations. To minimize the impact of the causal agent of SDS on date palm, native actinobacterial strains isolated from rhizosphere soils of healthy date palm plants were characterized according to their antifungal activities against F. solani DSM 106836 (Fs). Based on their in vitro abilities, two promising biocontrol agents (BCAs), namely Streptomyces tendae UAE1 (St) andStreptomyces violaceoruber UAE1 (Sv), were selected for the production of antifungal compounds and cell wall degrading enzymes (CWDEs), albeit their variations in synthesizing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD). Although both isolates showed antagonism when applied 7 days before the pathogen in the greenhouse experiments, the ACCD-producing Sv was relatively superior in its efficacy against SDS over the non-ACCD-producing St. This was evident from the symptoms of SDS in diseased date palm seedlings which were greatly reduced by Sv compared to St. On a scale of 5.0, the estimated disease severity indices in Fs-diseased seedlings were significantly (P < 0.05) reduced from 4.8 to 1.5 and 0.5 by St and Sv, respectively. Thus, the number of conidia of Fs recovered from plants pre-treated with both BCAs was comparable, but significantly (P < 0.05) reduced compared to plants without any BCA treatment. In addition, a significant (P < 0.05) decrease in ACC levels of both the root and shoot tissues was detected inSv + Fs seedlings to almost similar levels of healthy seedlings. However, in planta ACC levels highly increased in seedlings grown in soils infested with the pathogen alone or amended with St prior to F. solani infestation (St + Fs). This suggests a major role of ACCD production in relieving the stress of date palm seedlings infected with F. solani, thus supporting the integrated preventive disease management programs against this pathogen. This is the first report of effective rhizosphere actinobacterial BCAs to provide protection against SDS on date palm, and to help increase agricultural productivity in a more sustainable manner in the UAE and the other arid regions
Distribution and inter-regional relationship of amyloid-beta plaque deposition in a 5xFAD mouse model of Alzheimer’s disease
Get PDFAlzheimer’s disease (AD) is the most common form of dementia. Although previous studies have selectively investigated the localization of amyloid-beta (Aβ) deposition in certain brain regions, a comprehensive characterization of the rostro-caudal distribution of Aβ plaques in the brain and their inter-regional correlation remain unexplored. Our results demonstrated remarkable working and spatial memory deficits in 9-month-old 5xFAD mice compared to wildtype mice. High Aβ plaque load was detected in the somatosensory cortex, piriform cortex, thalamus, and dorsal/ventral hippocampus; moderate levels of Aβ plaques were observed in the motor cortex, orbital cortex, visual cortex, and retrosplenial dysgranular cortex; and low levels of Aβ plaques were located in the amygdala, and the cerebellum; but no Aβ plaques were found in the hypothalamus, raphe nuclei, vestibular nucleus, and cuneate nucleus. Interestingly, the deposition of Aβ plaques was positively associated with brain inter-regions including the prefrontal cortex, somatosensory cortex, medial amygdala, thalamus, and the hippocampus. In conclusion, this study provides a comprehensive morphological profile of Aβ deposition in the brain and its inter-regional correlation. This suggests an association between Aβ plaque deposition and specific brain regions in AD pathogenesis
SSR markers in revealing extent of genetic diversity and phylogenetic relationships among chickpea core collection accessions for Western Himalayas
No full textBackground
The exploration of genetic diversity is the key source of germplasm conservation and potential to broaden its genetic base. The globally growing demand for chickpea suggests superior/climate-resilient varieties, which in turn necessitates the germplasm characterization to unravel underlying genetic variation.
Methodology and results
A chickpea core collection comprising of diverse 192 accessions which include cultivated Cicer arietinum, and wild C. reticulatum, C. echinospermum, and C. microphyllum species were investigated to analyze their genetic diversity and relationship, by assaying 33 unlinked simple sequence repeat (SSR) markers. The results amplified a total of 323 alleles (Na), ranging from 2 to 8 with an average of 4.25 alleles per locus. Expected heterozygosity (He) differed from 0.46 to 0.86 with an average of 0.68. Polymorphic information content (PIC) ranged from 0.73 to 0.98 with an average of 0.89. Analysis of molecular variance (AMOVA) showed that most of the variation was among individuals (87%). Cluster analysis resulted in the formation of four distinct clusters. Cluster I represented all cultivated and clusters II, III, and IV comprised a heterogeneous group of cultivated and wild chickpea accessions.
Conclusion
We report considerable diversity and greater resolving power of SSR markers for assessing variability and interrelationship among the chickpea accessions. The chickpea core is expected to be an efficient resource for breeders for broadening the chickpea genetic base and could be useful for selective breeding of desirable traits and in the identification of target genes for genomics-assisted breeding
Phygital rural cultural heritage: A digitalisation approach for destination recovery and resilience
No full textPurpose This study examines a phygital approach to rural cultural heritage tourism, adopted by a rural community in Sapphaya, Chai Nat Province, Thailand, in response to the COVID-19 crisis. Specifically, it investigates the community's initiatives to amalgamate its physical and digital marketing communications to engage with consumers as a strategy for destination recovery and resilience. Design/methodology/approach This is a qualitative exploratory study involving three stages of action, applying two research approaches: (1) participatory action research (PAR) with Sapphaya's tourism stakeholders, and (2) social media research utilising netnographic analysis of Sapphaya's Tourism Social Enterprise social media pages. Findings The findings indicate that a phygital rural cultural heritage strategy can facilitate the interconnectivity between a destination's physical and digital dimensions of its cultural heritage tourism product, thereby enhancing its intrinsic value, meaning and experiential perceptions. Specifically, it recommends that a successful community-based phygitalisation strategy requires grassroots engagement across all stages of planning, development, implementation and management of the rural cultural heritage tourism product. Research limitations/implications There are limitations acknowledged in this research due to its focus on one rural destination site and community, as well as mobility and social-distancing challenges imposed by the pandemic. Nonetheless, there are opportunities for further research of the phygital rural cultural heritage tourism strategy and future empirical research to test the framework proposed. Practical implications The paper focuses on the cultural heritage tourism strategy adopted by a rural community across the physical-digital-phygital spectrum to augment its sustainable tourism development during a time of crisis. A framework for phygital rural cultural heritage as a strategy for destination resilience and recovery is also proposed. Originality/value This study is unique in that it adopts a local engagement approach to develop a cooperative community heritage management strategy, based upon local rural capacity building towards digitalisation and empowering innovative partnerships amongst its stakeholders