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The role of turbulent coherent structures on microalgal mixing for nutrient removal in jet and paddlewheel raceway ponds
Get PDFOutdoor studies were conducted on microalgae cultures in two raceway ponds (kept in constant motion with either jet or paddlewheel) with a flatbed to treat anaerobic digestion piggery effluent and to observe the characteristics of turbulence on microalgal mixing and growth. Acoustic Doppler Velocimeters (ADV) were deployed to record the instantaneous velocity components and acoustic backscatter as a substitution of microalgae concentration. The present research on microalgal mixing considers the effect of event-based turbulent features such as the widely known ‘turbulent bursting’ phenomenon. This is an important aspect, as turbulent coherent structures can result in microalgal mixing, which can lead to significant changes in microalgal growth. The experimental results presented in this paper of two contrasting environments of jet- and paddlewheel-driven ponds suggested that: (1) turbulent bursting events significantly contributed to microalgal mixing when paddlewheels and jets were used; (2) among four type of turbulent bursting events, ejections and sweeps contributed more to the total microalgal mixing; and, (3) a correlation was revealed using wavelet transform between the momentum and microalgal mixing flux when either jet or paddlewheel were used. Such similarities in jet and paddlewheel raceway ponds highlight the need to introduce turbulent coherent structures as an essential parameter for microalgal mixing studies
Population genomics of a predatory mammal reveals patterns of decline and impacts of exposure to toxic toads
Get PDFMammal declines across northern Australia are one of the major biodiversity loss events occurring globally. There has been no regional assessment of the implications of these species declines for genomic diversity. To address this, we conducted a species-wide assessment of genomic diversity in the northern quoll (Dasyurus hallucatus), an Endangered marsupial carnivore. We used next generation sequencing methods to genotype 10,191 single nucleotide polymorphisms (SNPs) in 352 individuals from across a 3220-km length of the continent, investigating patterns of population genomic structure and diversity, and identifying loci showing signals of putative selection. We found strong heterogeneity in the distribution of genomic diversity across the continent, characterized by (i) biogeographical barriers driving hierarchical population structure through long-term isolation, and (ii) severe reductions in diversity resulting from population declines, exacerbated by the spread of introduced toxic cane toads (Rhinella marina). These results warn of a large ongoing loss of genomic diversity and associated adaptive capacity as mammals decline across northern Australia. Encouragingly, populations of the northern quoll established on toad-free islands by translocations appear to have maintained most of the initial genomic diversity after 16 years. By mapping patterns of genomic diversity within and among populations, and investigating these patterns in the context of population declines, we can provide conservation managers with data critical to informed decision-making. This includes the identification of populations that are candidates for genetic management, the importance of remnant island and insurance/translocated populations for the conservation of genetic diversity, and the characterization of putative evolutionarily significant units
Graduate employability concerns amidst a crisis: Student perspectives from Singapore on COVID-19
No full textWith the ongoing challenges of COVID-19, global economies continue to face uncertainties, widespread workforce volatility and employment challenges. During a sustained crisis such as the COVID-19 pandemic, university students’ self-perceptions about their employability and future career choices in their chosen industry sectors may be affected. Therefore, this study investigates graduate employability concerns and the perceptions of undergraduate students regarding employment prospects and future job security confidence in their disciplines’ industry sectors in light of this global crisis. Through the employment of a mixed methods design, the study investigates the perceptions of graduating students from three disciplines in Singapore: Tourism, Communications and Information Technology. The findings indicate that COVID-19 had a positive impact on perceptions of jobs that could be performed from home and those in essential services. Concurrently, there were notable variances in the students’ perceptions regarding career prospects and job security confidence across the three disciplines with regard to the impact of the crisis on their industry sectors in general and themselves individually
Characterization of diet-dependent temporal changes in circulating short-chain fatty acid concentrations: A randomized crossover dietary trial
Get PDFBackground
Production of SCFAs from food is a complex and dynamic saccharolytic fermentation process mediated by both human and gut microbial factors. Knowledge of SCFA production and of the relation between SCFA profiles and dietary patterns is lacking.
Objectives
Temporal changes in SCFA concentrations in response to 2 contrasting diets were investigated using a novel GC-MS method.
Methods
Samples were obtained from a randomized, controlled, crossover trial designed to characterize the metabolic response to 4 diets. Participants (n = 19) undertook these diets during an inpatient stay (of 72 h). Serum samples were collected 2 h after breakfast (AB), after lunch (AL), and after dinner (AD) on day 3, and a fasting sample (FA) was obtained on day 4. The 24-h urine samples were collected on day 3. In this substudy, samples from the 2 extreme diets representing a diet with high adherence to WHO healthy eating recommendations and a typical Western diet were analyzed using a bespoke GC-MS method developed to detect and quantify 10 SCFAs and precursors in serum and urine samples.
Results
Considerable interindividual variation in serum SCFA concentrations was observed across all time points, and temporal fluctuations were observed for both diets. Although the sample collection timing exerted a greater magnitude of effect on circulating SCFA concentrations, the unhealthy diet was associated with a lower concentration of acetic acid (FA: coefficient: –17.0; SE: 5.8; P-trend = 0.00615), 2-methylbutyric acid (AL: coefficient: –0.1; SE: 0.028; P-trend = 4.13 × 10–4 and AD: coefficient: –0.1; SE: 0.028; P-trend = 2.28 × 10–3), and 2-hydroxybutyric acid (FA: coefficient: –15.8; SE: 5.11; P-trend: 4.09 × 10–3). In contrast, lactic acid was significantly higher in the unhealthy diet (AL: coefficient: 750.2; SE: 315.2; P-trend = 0.024 and AD: coefficient: 1219.3; SE: 322.6; P-trend: 8.28 × 10–4).
Conclusions
The GC-MS method allowed robust mapping of diurnal patterns in SCFA concentrations, which were affected by diet, and highlighted the importance of standardizing the timing of SCFA measurements in dietary studies. This trial was registered on the NIHR UK clinical trial gateway and with ISRCTN as ISRCTN43087333
Genetic mapping of QTLs for drought tolerance in chickpea (Cicer arietinum L.)
Get PDFChickpea yield is severely affected by drought stress, which is a complex quantitative trait regulated by multiple small-effect genes. Identifying genomic regions associated with drought tolerance component traits may increase our understanding of drought tolerance mechanisms and assist in the development of drought-tolerant varieties. Here, a total of 187 F8 recombinant inbred lines (RILs) developed from an interspecific cross between drought-tolerant genotype GPF 2 (Cicer arietinum) and drought-sensitive accession ILWC 292 (C. reticulatum) were evaluated to identify quantitative trait loci (QTLs) associated with drought tolerance component traits. A total of 21 traits, including 12 morpho-physiological traits and nine root-related traits, were studied under rainfed and irrigated conditions. Composite interval mapping identified 31 QTLs at Ludhiana and 23 QTLs at Faridkot locations for morphological and physiological traits, and seven QTLs were identified for root-related traits. QTL analysis identified eight consensus QTLs for six traits and five QTL clusters containing QTLs for multiple traits on linkage groups CaLG04 and CaLG06. The identified major QTLs and genomic regions associated with drought tolerance component traits can be introgressed into elite cultivars using genomics-assisted breeding to enhance drought tolerance in chickpea
Risk-Based operation of soft open points in distribution grids integrated with photovoltaic resources and energy storage systems
No full textElectronic-based technologies are becoming more interesting because of their advantages, such as quick response, higher lifespan, etc. Soft open point is a cutting-edge device that has been recently introduced for distribution grids. It is generally installed in tie switches, resulting in a transfer of the powers among two regions of the network. However, there are other distributed generation resources in the active distribution networks, like smart photovoltaic inverters (SPIs), energy storage systems (ESSs), diesel generators (DGs), etc. Accordingly, taking into account the coordination among mentioned technologies is essential. This paper aims to provide a strategy for simultaneous management of all mentioned resources based on a convex model, leading to taking advantage of commercial solvers, e.g., CPLEX. The uncertainties of loads and renewable energies directly affect such management schemes in addition to mentioned coordination. This paper, therefore, uses a robust framework entitled information-gap decision theory, which leads to reaching the solutions under harsh uncertainties. Here, the risk-averse strategy is utilized to model the uncertainties to achieve a robust model. The proposed method is finally evaluated under various cases by executing on a modified IEEE 33-bus test network. Through the results, SOP in the presence of SPIs, ESSs, and DGs can be an excellent remedy to improve the efficiency of networks
Performance evaluation of electrode design and material for a large animal electrical impedance tomography belt
Get PDFBackground
Electrical impedance tomography (EIT) produces lung ventilation images via a thoracic electrode belt. Robust electrode design and material, providing low electrode skin contact impedance (SCI), is needed in veterinary medicine. The aim of this study was to compare three EIT electrode designs and materials.
Methods
Simulations of cylindrical, rectangular and spiked electrode designs were used to evaluate electrode SCI as a function of electrode size, where skin contact was uneven. Gold-plated washers (EGW), zinc-plated rivets (EZR) and zinc-galvanised spikes (EZS) were assigned randomly on two interconnected EIT belts. Gel was applied to the cranial or caudal belt and placed on 17 standing cattle. SCI was recorded at baseline and 3, 5, 7, 9 and 11 minutes later.
Results
Simulations that involved electrodes with a greater skin contact area had lower and more uniform SCI. In cattle, SCI decreased with all electrodes over time (p < 0.01). Without gel, no difference was found between EGW and EZS, while SCI was higher for EZR (p < 0.03). With gel, SCI was lower in EGW and EZR (p < 0.026), with the SCI in EGW being the lowest (p < 0.01).
Limitations
Low numbers of animals and static electrode position may affect SCI.
Conclusions
Electrode design is important for EIT measurement, with larger electrode designs able to compensate for the use of less conductive materials. Gel is not necessary to achieve acceptable SCI in large animals
Skin health in northern Australia
Get PDFAchieving healthy skin requires the prevention of infectious diseases that affect the skin. Prevention activities range from environmental health improvements to address inequities in living situations, through to community-wide treatment programs to reduce transmission and improve skin health. In this paper we discuss the pathogens that cause and conditions that arise when skin is infected, the burden of disease in northern Australia, and some of the current research underway to address this high burden, which predominantly affects remote-living Aboriginal and Torres Strait Islander children and families
Oligonucleotides containing 2′-O-methyl-5-(1-phenyl-1,2,3-triazol-4-yl)uridines demonstrate increased affinity for RNA and induce exon-skipping in vitro
No full textThe nucleotide monomer containing the 1-phenyl-1,2,3-triazole group attached to the 5-position of 2′-O-methyluridine is hereby presented together with a derivative further substituted with a p-sulfonamide group on the phenyl ring. Both were conveniently synthesised, and synergistic effect of the modifications were demonstrated when introduced into oligonucleotides and hybridised to complementary RNA. The combination of stacking of the phenyltriazoles and the conformational steering from the 2′-OMe group gave thermally very stable duplexes. Exon skipping in the distrophin transcript using 20-mer 2′-OMePS sequences with two phenyltriazoles introduced in different positions with and without the sulfonamide demonstrated efficient exon skipping but at the same level as the 2′-OMePS reference ASO
Homogenising the design criteria of a community battery energy storage for better grid integration
Get PDFHistorically, minimum system demand has usually occurred overnight. However, in recent years, the increased penetration of rooftop photovoltaic systems (RPVs) has caused an even lower demand at midday, forcing some of the conventional generators to shut down only hours before the evening peak demand period. This further complicates the job of power system operators, who need to run the conventional generator at the minimum stable level at the midday low-demand period so that they can reliably supply power during the peak periods. Employing a community battery storage system can alleviate some of the technical issues caused by the high penetration of RPVs. This paper proposed a design criterion for community battery energy storage systems and employed the battery for the improvement of the duck curve profile and providing the desired level of peak-shaving. Furthermore, remote communities with high penetration of RPVs with a community battery energy storage can achieve the desired level of self-sufficiency. To this end, this study recommends and confirms an applicable design criterion for community battery energy storage. The study shows that the suitable size of community battery storage should be based on the community’s daily excess generation and consumption requirements. The results of various scenarios performed on the proposed design criterion show the extent to which the desired objectives of peak-shaving, duck curve mitigation, and self-sufficiency can be achieved