RSS 1.0Natural Sciences
The Department of Natural Sciences is located on Thornton Science Park, a modern expressly-designed site that profits from a recently-completed multi-million pound renovation that has created a state-of-the-art teaching and research facility. The site was home to Shell UK’s exploration and research centre since the 1940s, and its takeover by the University heralded the opportunity to apply its legacy to the continuation of world-class innovation and research in the North West.
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Improvement of water quality for mass anopheline rearing: Dynamics of larval tray bacterial communities under different water treatments revealed by 16S ribosomal RNA amplicon sequencingBACKGROUND: Immature anophelines inhabit aquatic environments with diverse physicochemical properties and microorganisms. In insectary settings, ammonia accumulation in larval rearing trays can lead to high larval mortality. Bacterial communities in these trays may influence ammonia levels through nitrification and denitrification. While symbiotic bacteria are known to be crucial for nutrition, digestion, reproduction, and immune responses in anophelines, the microbial communities specifically associated with Anopheles coluzzii larvae have not been characterised. METHODS AND RESULTS: Building on a study examining ammonia-capturing zeolite and water changes for rearing Anopheles coluzzii, this research characterised the bacterial communities using 16S rRNA gene sequencing to identify species linked to larval survival and phenotypic quality. Functional filters were applied to identify bacteria related to ammonia nitrification and their impact on larval development. qPCR was used to validate the sequencing data for the ten most significant bacteria. Water changes significantly reduced bacterial diversity and abundance, improving adult mosquito development and quality. In contrast, untreated trays showed a higher abundance of potentially harmful bacteria, adversely affecting development. Applying zeolite increased nitrifying bacteria presence, benefiting mosquito growth while lowering toxic bacteria levels-trends confirmed by qPCR. CONCLUSIONS: This study offers insights into the bacterial communities in mosquito larval-rearing water, highlighting species that could enhance ammonia nitrification and overall rearing success.
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Does measuring social attention lead to changes in behavior? A preliminary investigation into the implications of attention bias trials on behavior in Rhesus MacaquesA welfare assessment tool in development must satisfy several criteria before it is considered ready for general use. Some tools that meet many of these criteria have been criticized for their negative effect on welfare. We conducted a preliminary assessment of the impact of attention bias (AB) trials using threat-neutral conspecific face pairs followed by presumed neutral-positive filler stimuli on the behavior of 21 rhesus macaques (Macaca mulatta; 15 female). Behavioral observations were conducted following AB trials and repeated two weeks later when no AB trials had occurred (no trial: NT). The association between observation period and behavior was assessed using linear mixed-effects models in R. Trials did not impact any observed behavior except for fear, which was displayed by five monkeys over six trials (four NT). For this sample, there was a significant reduction in fear behavior following AB trials. We, therefore, found no evidence suggesting that AB trials negatively affect behaviour. AB protocols may be suitable for continued development for primate welfare assessment and we encourage researchers to include assessing test impact on welfare in their AB protocols.
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A unique ternary Ce(III)-quercetin-phenanthroline assembly with antioxidant and anti-inflammatory propertiesQuercetin is one of the most bioactive and common dietary flavonoids, with a significant repertoire of biological and pharmacological properties. The biological activity of quercetin, however, is influenced by its limited solubility and bioavailability. Driven by the need to enhance quercetin bioavailability and bioactivity through metal ion complexation, synthetic efforts led to a unique ternary Ce(III)-quercetin-(1,10-phenanthroline) ( 1 ) compound. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetric analysis (TGA), UV-Visible, NMR, Electron Spray Ionization-Mass Spectrometry (ESI-MS), Fluorescence, X-rays) revealed its solid-state and solution properties, with significant information emanating from the coordination sphere composition of Ce(III). The experimental data justified further entry of 1 in biological studies involving toxicity, ROS-suppressing potential, cell metabolism inhibition in Saccharomyces cerevisiae (S. cerevisiae) cultures, and plasmid DNA degradation. DFT calculations revealed its electronic structure profile, with in silico studies showing binding to DNA, DNA gyrase, and glutathione S-transferase, thus providing useful complementary insight into the elucidation of the mechanism of action of 1 at the molecular level and interpretation of its bio-activity. The collective work projects the importance of physicochemically supported bio-activity profile of well-defined Ce(III)-flavonoid compounds, thereby justifying focused pursuit of new hybrid metal-organic materials, effectively enhancing the role of naturally-occurring flavonoids in physiology and disease.
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Evaluation of different classes of additives on ash melting characteristics of garden grass wasteIn this work, the ash melting characteristics of crude garden grass waste (GGW) and its additive modulated mixtures were evaluated in a laboratory scale furnace by combusting the samples. For the purpose of understanding and rationalising the complex ash transformation characteristics of crude and additive modulated GGW samples in high-temperature thermochemical units, comprehensive theoretical knowledge and compositional ternary phase diagrams have been utilised in conjunction with the visual evaluation of the sintering degree of ash residues, coupled with their morphology and microchemistry results determined by the SEM–EDX and XRD analysis. This work proved that both raw and calcined eggshells can be utilised as Ca-rich anti-sintering additives as a substitute for commercially available additives such as lime and limestone for the enhancement of melting characteristics of low-melting garden grass ash. Kaolin exhibited the best anti-sintering characteristics for the elimination of ash melting of garden grass waste among all the additive mixtures tested, while no synergistic effects were observed in the Ca-rich and P-rich additive mixtures compared to their pure steams.
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Enhancing the repair performances of glass/epoxy wind turbine blades using a novel resistance-welding approachCommercial wind turbine (WT) blades that are now being operational globally, are primarily made of glass-reinforced composites using epoxy or polyester matrix systems, mainly epoxy. The industry is rapidly growing (2100 TWh currently; 17% growth annually) with a forecast of 7400 TWh by 2030. The average lifespan of a WT is 20-25 years, which signifies the importance of repairing the damaged blades. Amongst the methods that have been exploited so far, resistance welding shows eminent potential, due to its ease of operation, promptness of the repair process, and cost effectiveness. Resistance welding was exploited previously for repairing thermoplastic composites. But in this project, repair of thermoset composites was evaluated using thermoplastic welding medium. The project focused on parametric optimisation of resistance welding, evaluation of welding via single lap shear strength, and COMSOL multiphysics modelling to examine the homogeneity of heat-distribution across the welding region. Stainless steel mesh and carbon nonwoven sheet were used as heating elements, while polymethyl methacrylate and thermoplastic polyurethane were used as welding medium. The highest single lap shear strength was shown as 6.4 MPa when nonwoven carbon sheet was used along with thermoplastic polyurethane. COMSOL modelling with a custom-designed heating element showed improvement in thermal homogeneity; however, further modifications will be required to better optimisation of welding.
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Time temperature superposition of the dissolution of cellulose fibres by the ionic liquid 1-ethyl-3-methylimidazolium acetate with cosolvent dimethyl sulfoxideThe dissolution of cellulosic flax fibres in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) with cosolvent dimethyl sulfoxide (DMSO) has been studied. The fibres were submerged in the ionic liquid/DMSO mixtures at different temperatures for a range of dissolution times, then coagulated in water. After drying, cross sections of the fibres were analysed using an optical microscope, which was used to track the fraction of coagulated fibre. The temperature dependence of this coagulated fraction is found to follow an Arrhenius equation with a single activation energy of 100±10 kJ/mol. This value is, remarkably, independent of the weight fraction of DMSO used. This work quantifies the composition for the peak dissolution rate, which occurs at an equal weight fraction of DMSO and [C2mim][OAc]. Finally, this study reveals an equivalence between time, temperature and DMSO weight fraction in the dissolution of flax fibres.
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Effect of Silica Nanoparticles on Wettability of Oil-Wet SurfacesThe effect of silica nanoparticles and brine salinity variation on the wettability alteration of oil-wet surfaces was investigated in this paper. The rock and fluids of Kolo oilfield in Nigeria were used as case study and five brine salinities and two nanoparticles’ concentrations were investigated. The contact angle and Amott wettability index methods were used to investigate the wettability alteration potential of silica nanoparticles on oil-wet surfaces and intact core plugs, respectively. The results of the contact angle tests showed that the use of 1 g/L and 5 g/L silica nanoparticles reduced the oil-wet surface’s angle from 79o to 73o and 71o respectively in aqueous solution. Lower contact angles were however observed with the use of brines of different salinities with the lowest angles (69o and 68o ) being obtained with lowest salinity brine (90D). Which shows that the nanoparticles have the tendency to modify oil-wet surfaces towards waterwet condition irrespective of the brine salinities. Also, wettability alteration towards increasing water-wetness was observed with decrease in brine salinities and increase in the concentrations of the nanoparticles. Finally, the results of the Amott wettability index to water show that the application of nanoparticles modifies the intact rock wettability towards water-wet condition and higher oil production was observed with the spontaneous imbibition of nanofluid with 0.25 wettability index relative to that of the formation brine that was 0.1. The sediments of nanoparticles were however observed on top the rock core and at the base of the cell during the spontaneous imbibition process. This work presents experimental study on the wettability alteration potential of the application of silica nanoparticles in Kolo oilfield reservoir rock and fluids. The study presented in this paper is relevant to the design and implementation of nanoparticles enhanced oil recovery process.
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Captivity induces large and population‐dependent brain transcriptomic changes in wild‐caught cane toads (Rhinella marina)Gene expression levels are key molecular phenotypes at the interplay between genotype and environment. Mounting evidence suggests that short‐term changes in environmental conditions, such as those encountered in captivity, can substantially affect gene expression levels. Yet, the exact magnitude of this effect, how general it is, and whether it results in parallel changes across populations are not well understood. Here, we take advantage of the well‐studied cane toad, Rhinella marina, to examine the effect of short‐term captivity on brain gene expression levels, and determine whether effects of captivity differ between long‐colonized and vanguard populations of the cane toad's Australian invasion range. We compared the transcriptomes of wild‐caught toads immediately assayed with those from toads captured from the same populations but maintained in captivity for seven months. We found large differences in gene expression levels between captive and wild‐caught toads from the same population, with an over‐representation of processes related to behaviour and the response to stress. Captivity had a much larger effect on both gene expression levels and gene expression variability in toads from vanguard populations compared to toads from long‐colonized areas, potentially indicating an increased plasticity in toads at the leading edge of the invasion. Overall, our findings indicate that short‐term captivity can induce large and population‐specific transcriptomic changes, which has significant implications for studies comparing phenotypic traits of wild‐caught organisms from different populations that have been held in captivity.
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Male survivorship and the evolution of eusociality in partially bivoltine sweat beesEusociality, where workers typically forfeit their own reproduction to assist their mothers in raising siblings, is a fundamental paradox in evolutionary biology. By sacrificing personal reproduction, helpers pay a significant cost, which must be outweighed by indirect fitness benefits of helping to raise siblings. In 1983, Jon Seger developed a model showing how in the haplodiploid Hymenoptera (ants, wasps and bees), a partially bivoltine life cycle with alternating sex ratios may have promoted the evolution of eusociality. Seger predicted that eusociality would be more likely to evolve in hymenopterans where a foundress produces a male-biased first brood sex ratio and a female-biased second brood. This allows first brood females to capitalize on super-sister relatedness through helping to produce the female-biased second brood. In Seger’s model, the key factor driving alternating sex ratios was that first brood males survive to mate with females of both the second and the first brood, reducing the reproductive value of second brood males. Despite being potentially critical in the evolution of eusociality, however, male survivorship has received little empirical attention. Here, we tested whether first brood males survive across broods in the facultatively eusocial sweat bee Halictus rubicundus. We obtained high estimates of survival and, while recapture rates were low, at least 10% of first brood males survived until the second brood. We provide empirical evidence supporting Seger’s model. Further work, measuring brood sex ratios and comparing abilities of first and second brood males to compete for fertilizations, is required to fully parameterize the model.
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Assessing risk factors for drug storage practices in veterinary surgeries: A questionnaire study of UK veterinary professionalsBACKGROUND: Safe drug storage practices are essential in veterinary practice to maintain optimal standards of animal care. Practical challenges in clinic may impact their uptake, which could affect drug efficacy and the success of treatment. The UK is presumed to provide high standards for animal care and welfare in the veterinary profession and may provide an interesting case study to assess veterinary drug storage practices. METHODS: An online survey with 184 practice participants assessed UK veterinary professionals’ responses on drug storage practices. This included socio-demographic information and questions or statements that examined storage practices compliant with the requirements established by the Royal College of Veterinary Surgeons (RCVS), the regulatory body for veterinary practice in the UK. RESULTS: Overall, practices followed RCVS recommended measures, though there was clear selectivity for stock temperature checks (72.2 %), over other measures, particularly, replacing stock (54.4%) and returning medications to refrigerated storage (52.5%). Clinical experience and practice type impacted most on drug storage practices, with more experienced clinicians and small animal practices showing greater uptake of best measures. CONCLUSIONS: We suggest that practices should adopt all of the RCVS measures in relation to veterinary drug storage practices. Socio-demographic factors should be considered because they can act as risk factors influencing best practice in clinics. Our findings may have wider implications for the veterinary profession in general, given similar demographic trends in veterinary practice in many European countries.
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Job satisfaction and animal welfare at slaughter: A survey of Official Veterinarians in the United Kingdom and Republic of IrelandIn the UK and the Republic of Ireland, Official Veterinarians (OVs) are employed by the Food Standards Agency and the Food Safety Authority, respectively, as legal authorities for both animal welfare and food safety. However, little is known about job satisfaction in this profession which has the potential to impact professionals’ well-being and performance. Moreover, despite animal welfare issues being a reality that OVs witness, we do not yet understand how OVs perceive these issues at slaughter or whether this impacts job satisfaction. We assessed OVs’ perceptions on job satisfaction and views on welfare at slaughter across the UK and ROI, through an online questionnaire with 113 participants, which included socio-demographic information of participants and questions or statements about different aspects of job satisfaction and animal welfare issues at slaughter. While most OVs committed to their work they reported issues that may compromise job satisfaction, such as often experiencing loneliness at work, threatening situations and sleep disorders. Moreover, job satisfaction was often impacted by animal welfare incidents, and conflicts with food business operators were considered one of the greatest barriers to improving welfare at slaughter. There is also the likelihood of professionals’ individual ethical values being challenged since OVs are virtually certain to witness religious slaughter yet disagree with this practice to the extent that they consider it should be banned. We reveal significant challenges associated with the role of OV that justify creation of a support network to assist and safeguard this profession, as well as animal welfare at slaughter.
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Exploring the acceleration of sustainability transitions: The case of the transition to a low-carbon hydrogen network in North West EnglandClimate change attributable to anthropogenic emissions presents a major sustainability challenge. Low-carbon hydrogen could have an important role in decarbonisation by replacing the use of fossil fuels across various heavy-emitting sectors in the UK. The North West of England is well-positioned for the development of a low-carbon hydrogen network due to its existing infrastructure, assets and capabilities. The transition to low-carbon hydrogen can be thought of as a sustainability transition because it is goal oriented and encompasses niche innovations that exhibit a lower techno-economic performance than established technologies. While transitions typically occur over decades, the urgency of decarbonisation has led scholars to explore how they could be accelerated. Guided by the Multi-Level Perspective (MLP) approach to understanding sustainability transitions, this research explores how the transition to a low-carbon hydrogen network in England’s North West region could be accelerated. It does so by employing an explorative case study methodology, collecting primary data through semi-structured interviews and virtual workshop sessions. The data is analysed using two conceptual frameworks and further enriched by drawing upon conceptualisations from MLP literature. The first framework outlines examples of five acceleration mechanisms observed across hydrogen transition initiatives in North West England, highlighting the key activities and tensions with each. Findings indicate that embedding is less frequently observed than other mechanisms due to broader challenges associated with instrumentalising, such as design limitations of national funding schemes and a lack of frameworks to encourage private sector investment in low-carbon hydrogen technologies. The second framework explores the role of institutional and organisational drivers in promoting complementarity changes to accelerate the transition to low-carbon hydrogen, while also identifying potential transition bottlenecks. The findings suggest that institutional drivers aimed at improving the economics of low-carbon hydrogen innovations could be crucial for catalysing complementarity changes. Several high-significance bottlenecks that could prohibit the deployment of hydrogen innovations are identified, including persistent lock-in, bootstrapping, the weak spot bottleneck and public opposition. These bottlenecks are likely to arise during the experimentation phase of the transition, suggesting the need for their resolution in the short term. This research emphasises the importance of institutional support in accelerating sustainability transitions. Examples of institutional support identified for the case studied in this research included funding schemes that enable the actual demonstration of hydrogen innovations, education programmes that may enhance social acceptance of hydrogen innovations, and measures that address the unfavourable economics of low-carbon hydrogen such as supportive business models, carbon tax reforms, and end-user subsidies. Additionally, this research highlights the need for a co-ordinated approach when strategically planning the development and deployment of low-carbon innovations, both in the early phases and throughout the course of the transition, to enable the effective implementation of institutional measures, and to mitigate against potential transition bottlenecks.
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Current status of Glossina population ecologyBACKGROUND: Vector control remains the most visible method for large scale control of trypanosomiasis; there is a lack of suitable prophylactic drugs and vaccines against trypanosomiases and chemotherapeutic agents remain too expensive and dangerous for most people in endemic areas. Glossina populations are the target units and therefore an in-depth understanding of their ecology is a pre-requisite to the development of effective control measures. SAMPLING METHODS: Refers to methods of catching tsetse flies in the field. Earlier Researchers utilized walking parties to catch flies or standing catch with hand nets. Studies in the 1970s highlighted the shortcomings of these methods. A variety of traps has since been developed for diverse species. POPULATION DYNAMICS: Refers to changes in population abundance over time. Three processes (dispersal, natality, mortality) are involved in determining population levels. Geographic structure is the distribution and abundance within and among populations. Based on direct observations, mark-recapture protocols or radio-tracking, earlier view was that Glossina dispersal was random. Currently, the best available description is a diffusion process; flies at the margins of the distributional range begin the process, which gradually moves inwards. Calculation of growth rates is easier for small closed Glossina populations. There is a consensus among tsetse ecologists that both density-dependent and density-independent factors are important in the regulation of tsetse numbers. POPULATION GENETICS: It encompasses two distinct but related components: demographic and genetic distribution of genetic variation and the result of migration, selection mutation, genetic drift and related factors: New molecular genetics techniques have allowed insights into many fields. CONCLUSION: There have been significant advances in Glossina ecology over the past 3 decades. These have been possible because of the availability of comprehensive data from long-term field studies and the introduction of new molecular genetics techniques that have allowed insights into many fields. Glossina population genetics and manipulation of prokaryotic symbiont species may provide avenues for management innovations to confront the intractable problem of trypanosomiasis in Africa.
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Effect of water source and feed regime on development and phenotypic quality in Anopheles gambiae (s.l.): prospects for improved mass-rearing techniques towards release programmesBACKGROUND: In many malaria-endemic sub-Saharan countries, insecticide resistance poses a threat to existing mosquito control measures, underscoring the need for complementary control methods such as sterile and/or genetically-modified mosquito release programmes. The sibling species Anopheles gambiae and An. coluzzii are responsible for malaria transmission in most of this region. In their natural habitat, these species generally breed in clean, soft water and it is believed that divergent preference in their larval breeding sites have played a role in their speciation process. Mosquito release programmes rely on the rearing of mosquitoes at high larval densities. Current rearing protocols often make use of deionised water regardless of the strain reared. They also depend on a delicate balance between the need for adequate feeding and the negative effect of toxic ammonia and food waste build-up on mosquito development, making managing and improving water quality in the insectary imperative. METHODS: Here, we investigated the impact of water source and feed regimes on emergence rate and phenotypic quality of mosquitoes in the insectary. First-instar larvae of An. gambiae (Kisumu strain) and An. coluzzii (Mopti and VK3 strains) were reared in three water sources with varying degrees of hardness (deionised, mineral and a mix of the two), with a daily water change. Larvae were fed daily using two standardised feeding regimes, solution and powder feed. RESULTS: Water source had a significant impact on mosquito size and development time for all strains. Earlier emergence of significantly larger mosquitoes was observed in mineral water with the smallest mosquitoes developing later from deionised water. Wing-length was significantly longer in mineral, mixed water and in powder feed, irrespective of sex, strains or water types. Deionised water was the least favourable for mosquito quality across all strains. CONCLUSIONS: Mineral water and powder feed should be used in rearing protocols to improve mosquito quality where the optimal quality of mosquitoes is desired. Although results obtained were not significant for improved mosquito numbers, the phenotypic quality of mosquitoes reared was significantly improved in mineral water and mix water. Further studies are recommended on the impact mineral water has on other fitness traits such as longevity, fecundity and mating competitiveness.
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Laboratory and microcosm experiments reveal contrasted adaptive responses to ammonia and water mineralisation in aquatic stages of the sibling species Anopheles gambiae (sensu stricto) and Anopheles coluzziiBackground: The sibling species of the malaria mosquito, Anopheles gambiae (sensu stricto) and Anopheles coluzzii co-exist in many parts of West Africa and are thought to have recently diverged through a process of ecological speciation with gene flow. Divergent larval ecological adaptations, resulting in Genotype-by-Environment (G × E) interactions, have been proposed as important drivers of speciation in these species. In West Africa, An. coluzzii tends to be associated with permanent man-made larval habitats such as irrigated rice fields, which are typically more eutrophic and mineral and ammonia-rich than the temporary rain pools exploited by An. gambiae (s.s.). Methods: To highlight G × E interactions at the larval stage and their possible role in ecological speciation of these species, we first investigated the effect of exposure to ammonium hydroxide and water mineralisation on larval developmental success. Mosquito larvae were exposed to two water sources and increasing ammonia concentrations in small containers until adult emergence. In a second experiment, larval developmental success was compared across two contrasted microcosms to highlight G × E interactions under conditions such as those found in the natural environment. Results: The first experiment revealed significant G × E interactions in developmental success and phenotypic quality for both species in response to increasing ammonia concentrations and water mineralisation. The An. coluzzii strain outperformed the An. gambiae (s.s.) strain under limited conditions that were closer to more eutrophic habitats. The second experiment revealed divergent crisscrossing reaction norms in the developmental success of the sibling species in the two contrasted larval environments. As expected, An. coluzzii had higher emergence rates in the rice paddy environment with emerging adults of superior phenotypic quality compared to An. gambiae (s.s.), and vice versa, in the rain puddle environment. Conclusions: Evidence for such G × E interactions lends support to the hypothesis that divergent larval adaptations to the environmental conditions found in man-made habitats such as rice fields in An. coluzzii may have been an important driver of its ecological speciation.
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Improvement of water quality for mass anopheline rearing: evaluation of the impact of ammonia-capturing zeolite on larval development and adult phenotypic qualityBackground: Malaria vector control approaches that rely on mosquito releases such as the sterile insect technique (SIT) and suppression or replacement strategies relying on genetically modified mosquitoes (GMM) depend on effective mass production of Anopheles mosquitoes. Anophelines typically require relatively clean larval rearing water, and water management techniques that minimise toxic ammonia are key to achieving optimal rearing conditions in small and large rearing facilities. Zeolites are extensively used in closed-system fish aquaculture to improve water quality and reduce water consumption, thanks to their selective adsorption of ammonia and toxic heavy metals. The many advantages of zeolites include low cost, abundance in many parts of the world and environmental friendliness. However, so far, their potential benefit for mosquito rearing has not been evaluated. Methods: This study evaluated the independent effects of zeolite and daily water changes (to simulate a continuous flow system) on the rearing of An. coluzzii under two feed regimes (powder and slurry feed) and larval densities (200 and 400 larvae per tray). The duration of larval development, adult emergence success and phenotypic quality (body size) were recorded to assess the impact of water treatments on mosquito numbers, phenotypic quality and identification of optimal feeding regimes and larval density for the use of zeolite. Results: Overall, mosquito emergence, duration of development and adult phenotypic quality were significantly better in treatments with daily water changes. In treatments without daily water changes, zeolite significantly improved water quality at the lower larval rearing density, resulting in higher mosquito emergence and shorter development time. At the lower larval rearing density, the adult phenotypic quality did not significantly differ between zeolite treatment without water changes and those with daily changes. Conclusions: These results suggest that treating rearing water with zeolite can improve mosquito production in smaller facilities. Zeolite could also offer cost-effective and environmentally friendly solutions for water recycling management systems in larger production facilities. Further studies are needed to optimise and assess the costs and benefits of such applications to Anopheles gambiae (s.l.) mosquito-rearing programmes.
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An in-depth analysis of barriers to corporate sustainability?Establishing sustainable and resilient businesses are among the key drivers behind the unprecedented demand for the transition and transformation of sustainable growth models. Driven by a desire to remain competitive amidst economic turmoil and climate change, organisations are embedding sustainable measures into their long-term goals and strategies. This is demonstrated by developing and implementing Net-Zero targets and associated plans. However, the greatest challenge is whether such momentum will be retained and how organisations can maintain the drive. Although this is a positive move towards climate-related actions from organisations and stakeholders, it is taking longer than anticipated to be realised and actualised. This necessitates the urgency in understanding the intricacies of corporate sustainability matrices. The question as to why attaining a positive climatic state has taken almost half a century needs to be explored when compared to scenarios where the implementation of sustainable related measures has taken less time. This paper provides a review of the barriers that are making sustainability unattractive for corporate organisations. Finance gaps, the complexity of organisational sustainability, reporting frameworks, tools, and procedures coupled with considerable marketing and communication in a business-as-usual environment are key barriers to corporate sustainability. Our findings provide recommendations for policymakers, and stakeholders across the corporate sustainability platform by delivering a holistic approach to overcome the bottlenecks for implementation, action, and monitoring.
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Defence logistics in contextThe principal purpose of this chapter is to examine aspects of defence logistics, principally operational logistics, in order to shed light on some of the realities that give it its particular character, or at least some of its character. One possible approach is to analyse the defence supply chain and support chain using an analytical framework built around established through life support and supply chain paradigms, concepts, and ideas, drawn from the commercial sector. Another approach is to examine some specific characteristics of defence supply chains and support chains, some of their attributes, and some of their practical realities, and whilst doing so refer to the established paradigms, concepts, and ideas for comparison, but only where it seems appropriate to do so, in the hope that they might to some extent act as reference points by which defence logistics can be better understood by somebody not directly involved in its planning and delivery. One aim of this chapter is to examine the freedoms which defence departments and defence logisticians have in shaping their business, and the factors, or ‘realities’, which constrain them.
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Weighted echo state graph neural networks based on robust and epitaxial film memristorsHardware system customized toward the demands of graph neural network learning would promote efficiency and strong temporal processing for graph‐structured data. However, most amorphous/polycrystalline oxides‐based memristors commonly have unstable conductance regulation due to random growth of conductive filaments. And graph neural networks based on robust and epitaxial film memristors can especially improve energy efficiency due to their high endurance and ultra‐low power consumption. Here, robust and epitaxial Gd: HfO2‐based film memristors are reported and construct a weighted echo state graph neural network (WESGNN). Benefiting from the optimized epitaxial films, the high switching speed (20 ns), low energy consumption (2.07 fJ), multi‐value storage (4 bits), and high endurance (109) outperform most memristors. Notably, thanks to the appropriately dispersed conductance distribution (standard deviation = 7.68 nS), the WESGNN finely regulates the relative weights of input nodes and recursive matrix to realize state‐of‐the‐art performance using the MUTAG and COLLAB datasets for graph classification tasks. Overall, robust and epitaxial film memristors offer nanoscale scalability, high reliability, and low energy consumption, making them energy‐efficient hardware solutions for graph learning applications.
