7 research outputs found
Ageing of reticulate Si-SiC foams in porous burners
No full textSi-SiC open cell foams with porosity >87% and high pore sizes (4-7 mm) are commonly employed as active zone in porous burners for heat radiation applications. In a porous burner, the solid porous body let the heat recirculate from the hot combustion products to the incoming reactants. The result is that the flame is confined within the foam, meaning high thermomechanical loadings on its constituent material. A set of commercial Si-SiC foams from the same production batch was aged with flat porous burners. Thermal cycles ramp-up, dwell and cooling, as well as burner set-up (power: 15 kW, fuel/air ratio: 1.5), were chosen based on previous experience. Before aging, each foam was first cut in bars ready for bending tests, reassembled into the burner foam configuration and operated. As produced and aged samples were physically, mechanically and chemically analysed and results compare
Efeito de diferentes intensidades de manejo simuladas sobre diversidade genética de uma população natural de palmiteiro (Euterpe edulis martius)
No full textUniversidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Recursos Genéticos Vegetais
The life and work of the Revd. T.H.E.C. Espin, perpetual curate of Tow Law, with special reference to his astronomical research
No full textNo abstract supplie
A standardisation framework for bio‐logging data to advance ecological research and conservation
No full textFunding: AMMS was funded by a 2020 Pew Fellowship in Marine Conservation, ARC DE170100841, and also supported by AIMS. CR was the recipient of a Radcliffe Fellowship at the Radcliffe Institute for Advanced Study, Harvard University.Bio-logging data obtained by tagging animals is key to addressing global conservation challenges. However, the many thousands of existing bio-logging datasets are not easily discoverable, universally comparable, nor readily accessible through existing repositories and across platforms. This slows down ecological research and effective management. A set of universal standards is needed to ensure discoverability, interoperability, and effective translation of bio-logging data into research and management recommendations. We propose a standardisation framework adhering to existing data principles (FAIR: Findable, Accessible, Interoperable, and Reusable; and TRUST: Transparency, Responsibility, User focus, Sustainability and Technology) and involving the use of simple templates to create a data flow from manufacturers and researchers to compliant repositories, where automated procedures should be in place to prepare data availability into four standardised levels: (i) decoded raw data, (ii) curated data, (iii) interpolated data, and (iv) gridded data. Our framework allows for integration of simple tabular arrays (e.g., csv files) and creation of sharable and interoperable network Common Data Form (netCDF) files containing all the needed information for accuracy-of-use, rightful attribution (ensuring data providers keep ownership through the entire process), and data preservation security. We show the standardisation benefits for all stakeholders involved, and illustrate the application of our framework by focusing on marine animals and by providing examples of the workflow across all data levels, providing data examples, including filled templates and code to process data between levels, as well as templates to prepare netCDF files ready for sharing. Adoption of our framework will facilitate collection of Essential Ocean Variables (EOVs) in support of the Global Ocean Observing System (GOOS) and inter-governmental assessments (e.g., the World Ocean Assessment), and will provide a starting point for broader efforts to establish interoperable bio-logging data formats across all fields in animal ecology.Peer reviewe
Embryonic stem cells: modelling effects ofearly embryo environment
No full textThe Developmental Origins of Health and Disease (DOHaD) hypothesis proposes that embryonic environment can induce permanent changes in metabolism during development, increasing the risk of disease in adults. Adverse environments during critical stages of gestation are sufficient to induce adaptations in offspring and disease susceptibility in later life. Rodent models show that maternal diet exclusively during preimplantation development induces cardiovascular and metabolic disease in adult offspring. Changes must therefore occur within the distinct cell populations of the early embryo and be maintained throughout development. Determining adaptive mechanisms has been challenging due to the small size of the early embryo, and genetic variability in outbred strains previously used. We generated mouse embryonic stem (ES) cells from inbred C57BL/6 mice as a model to overcome these problems. These were used to characterise mechanisms associated with the embryo’s adaptive responses to maternal diet. ES cell lines were derived from blastocysts of C57BL/6 mice assigned to either an isocaloric low protein diet (LPD), or a control diet exclusively through preimplantation development. ES cell lines were characterised for karyotype, sex, gene expression, and functional characteristics including proliferation, death, and metabolism at standardised passages. LPD had no impact on blastocyst formation in vivo or blastocyst cell lineage allocation. Experimental conditions did affect blastocyst outgrowth development in vitro. LPDoutgrowths cultured with less feeder fibroblasts showed slower development than controls. Although LPD blastocyst outgrowth was comparable to controls under high feeder growth conditions, there was a significant reduction in the capacity for ES cell derivation. There was a prominent sex bias towards male ES cell lines. These ES cells retained similar levels of gene expression related to pluripotency, housekeeping and developmental functions irrespective of diet. LPD did not affect growth or metabolism. These cells however showed increased basal apoptosis, and reduced levels of phosphorylated Extracellular signal-regulated kinase (ERK). The reduced ES cell isolation efficiency may indicate a reduced number of pluripotent cells present within the early embryo or increased sensitivity of these cells in response to maternal LPD. Increased apoptosis in ES cells derived from LPD-blastocysts reveal that these cells are indeed more sensitive. Reduced activated ERK may suggest that dysregulated ERK-mediated survival signalling causes enhanced apoptosis. Such adaptations in the early embryo may impact on lineage allocation as differentiation occurs. These ES cell lines may provide a model to investigate such mechanistic adaptations in post-implantation tissues providing further insight into foetal responses to poor nutrition and the induction of adult onset disease
Physical and geochemical characterisation of canal sediments in the Black Country, West Midlands.
No full textA thesis submitted in fulfilment of the requirements of the University of
Wolverhampton for the award of the degree of Doctor of Philosophy (Ph.D.)Potentially harmful elements (PHEs) have been researched in a wide variety of disciplines, including pedology, chemistry, pollution science and medicine. Within the scientific community, emphasis has usually been placed on the toxic elements, such as cadmium, chromium, lead and arsenic, but rarely has there been consideration of interactions between PHEs, the sediment matrix and processes occurring in the sediments. Dredging of canals is needed for navigability purposes and consequently testing of dredged sediments (to assess whether sediments are hazardous) and landfilling can be costly for British Waterways facing constantly changing regulations and reduction in government grants. PHE mobility and availability in canal sediments can be affected by oxygen availability, pH and Redox. Remediation is thus becoming a priority for British Waterways to limit their operational costs. Zeolites, a type of remediation tool, have been widely studied in the past 30 years due to their attractive properties, such as molecular-sieving, high cation exchange capacities and their affinity for PHEs. The pilot study to investigate the efficiency of the clinoptilolite showed that there was a concentration difference between PHEs adsorbed by the clinoptilolite and the PHE concentration lost from the sediments from three sites in the West Midlands. Thorough characterisation of the sediments was needed to understand the speciation of the PHEs and the secondary processes occurring in the sediments. The different components of the sediments were analysed using various analytical methods, such as X-Ray Fluorescence spectroscopy (XRF), particle size and X-ray Diffraction (XRD) for the solid-inorganic phase, Ion Chromatography (IC) and Inductively Coupled Plasma-Optical Emissions Spectroscopy (ICP-OES) for the liquid phase (pore water), Gas Chromatography-Mass Spectrometry (GC-MS) and organic loss on ignition for the organic phase, pH and Redox for the electrochemistry of the sediments and Scanning Electron Microscope with Energy Dispersive X-Ray analysis (SEM-EDX) for microscopy and imaging. The British Geological Survey (BGS) sequential extraction method was used to investigate the different phases in the sediments. pH remained near neutral for all three sites and Redox remained anoxic. Organic contents for all three sites were around 30% and contained most of the polycyclic aromatic hydrocarbons considered hazardous. Pore water showed only high concentrations of sulphates but low concentrations of PHEs, suggesting PHEs were not mobile. Sequential extraction confirmed the other results showing that PHEs were mainly associated with stable phases, such as iron and manganese oxides or sulphides. The results have been taken into consideration to design a new remediation strategy to maximise efficiency of the zeolite
Global COVID-19 lockdown highlights humans as both threats and custodians of the environment
No full textThe global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness
