242 research outputs found
Integral length scales in a low-roughness atmospheric boundary layer
This paper discusses the integral length scales in a low-roughness atmospheric boundary layer (ABL), based on the high-fidelity measurements of wind velocity. Results from the analysis shows that longitudinal integral length scales follow a linear relationship with height in a low-roughness ABL that deviates significantly from semi-empirical Engineering Sciences Data Unit (ESDU) 85020 model derived for open country and urban terrains with larger surface roughness heights. Although the model accurately predicts the integral length scales non-dimensionalised relative to the boundary layer thickness for the majority of the profile, they are over-predicted by more than double in the lowest 10% of the ABL, corresponding to the atmospheric surface layer (ASL). The analysis shows that the largest eddies at lower heights in the ASL over a very low roughness desert terrain have length scales similar to the characteristic lengths of physical structures positioned on the ground, which corresponds to the maximum wind loads for buildings. Hence, it is recommended that the integral length scales in the ASL are characterised over an estimated range at each of the four terrain categories in AS/NZS 1170.2 to ensure that buildings and other large physical structures can be optimised in terms of their size and location.M.J. Emes, M. Arjomandi, R.M. Kelso and F. Ghanad
Diverse Spatial, Temporal, and Sexual Expression of Recently Duplicated Androgen-Binding Protein Genes in \u3ci\u3eMus musculus\u3c/i\u3e
Background
The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization). Results
It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible. We observed expression of six Abpa paralogues and five Abpbg paralogues in ten glands and other organs located predominantly in the head and neck (olfactory lobe of the brain, three salivary glands, lacrimal gland, Harderian gland, vomeronasal organ, and major olfactory epithelium). These Abp paralogues differed dramatically in their specific expression in these different glands and in their sexual dimorphism of expression. We also studied the appearance of expression in both late-stage embryos and postnatal animals prior to puberty and found significantly different timing of the onset of expression among the various paralogues. Conclusion
The multiple changes in the spatial expression profile of these genes resulting in various combinations of expression in glands and other organs in the head and face of the mouse strongly suggest that neofunctionalization of these genes, driven by adaptive evolution, has occurred following duplication. The extensive diversification in expression of this family of proteins provides two lines of evidence for a pheromonal role for ABP: 1) different patterns of Abpa/Abpbg expression in different glands; and 2) sexual dimorphism in the expression of the paralogues in a subset of those glands. These expression patterns differ dramatically among various glands that are located almost exclusively in the head and neck, where the sensory organs are located. Since mice are nocturnal, it is expected that they will make extensive use of olfactory as opposed to visual cues. The glands expressing Abp paralogues produce secretions (lacrimal and salivary) or detect odors (MOE and VNO) and thus it appears highly likely that ABP proteins play a role in olfactory communication
Investigating the awareness of decision-making heuristics and biases in the selection and definition of infrastructure projects
The decision-making process can be biased by virtue of the role that mental shortcuts play in human decision making. Although many researchers have studied this fact in form of psychological behaviours and behavioural economics, limited research has explored the role of heuristics and biases in the selection and definition of infrastructure projects. Accordingly, this paper provides a baseline for further research, presented in a "codex model". A survey has been conducted to address the extent of people's awareness of heuristics and biases. The results show that more than 80% of the participants are not familiar with the concept of decision-making heuristics and biases. This research is important because it highlights the fact that increasing the awareness of decision-making heuristics and biases may lead to improved project decisions
Effect of turbulence characteristics in the atmospheric surface layer on the peak wind loads on heliostats in stow position
This study investigates the dependence of peak wind load coefficients on a heliostat in stow position on turbulence characteristics in the atmospheric surface layer, such that the design wind loads, and thus the size and cost of heliostats, can be further optimised. Wind tunnel experiments were carried out to measure wind loads and pressure distributions on a heliostat in stow position exposed to gusty wind conditions in a simulated part-depth atmospheric boundary layer (ABL). Force measurements on different-sized heliostat mirrors at a range of heights found that both peak lift and hinge moment coefficients, which are at least 10 times their mean coefficients, could be optimised by stowing the heliostat at a height equal to or less than half that of the mirror facet chord length. Peak lift and hinge moment coefficients increased linearly and approximately doubled in magnitude as the turbulence intensity increased from 10% to 13% and as the ratio of integral length scale to mirror chord length Lux/c increased from 5 to 10, compared to a 25% increase with a 40% increase in freestream Reynolds number. Pressure distributions on the stowed heliostat showed the presence of a high-pressure region near the leading edge of the heliostat mirror that corresponds to the peak power spectra of the fluctuating pressures at low frequencies of around 2.4 Hz. These high pressures caused by the break-up of large vortices at the leading edge are most likely responsible for the peak hinge moment coefficients and the resonance-induced deflections and stresses that can lead to structural failure during high-wind events.Matthew J. Emes, Maziar Arjomandi, Farzin Ghanadi, Richard M. Kels
Towards Ethics in Robotic Cities
A new concept has emerged from the Internet of Things (IoT) called the Internet of Robotic Things (IoRT). Within urban environments, decisions concerning our habitat are commonly made via democratically or by consensus. Future systems involving IoT and IoRT will include, not only hard elements, but also software, (such as bots) and social to soft system interactions, with many stakeholders resulting in ambiguity and unclear requirements. In the case of wicked problems, this research looks into the area of knowledge co-creation and Problem Structuring Methods (PSM), which work better. In the near future, we will be surrounded by a large number of software and hardware systems that uses collaborative AI, or at least co-dependent AI. Similar to the science of human to computer interaction, we will have distributed social systems to distributed AI interaction. This research sheds light on ethics as a socio-technical element when modelling robotic cities infrastructures. The paper considers full actuation autonomy and control by IoT/IoRT, therefore adding software bots and social soft systems into the mix, as well as interdependencies of infrastructure hard-systems. Past robotics research of ethics debates whether ethics should be taught to robots vs hard programmed into robots, whilst a third school of thought discusses the philosophical implications. This research takes an alternative route to that. It provides definitions, establishes common grounds and opens discussions regarding how we can model our societies' interactions with a distributed Artificial Intelligent (AI) system; replacing the various human experts running the autonomous city. The research concludes with a preliminary proposal that is an abstraction resulted from a literature review conducted in this topic area
Optimisation of the size and cost of heliostats in a concentrating solar thermal power tower plant
Concentrating solar thermal (CST) power tower (PT) is one of the most promising renewable technologies for large-scale electricity production, however the main limitation of PT systems is their significantly larger levelised cost of electricity (LCOE) relative to base load energy systems. One opportunity to lower the LCOE is to reduce the capital cost of heliostats through optimisation of the size and position of heliostat mirrors to withstand maximum wind loads during high-wind conditions when aligned parallel to the ground in the stow position.
Wind tunnel experiments were carried out to measure the forces on thin flat plates of various sizes at a range of heights in a simulated part-depth atmospheric boundary layer (ABL). Calculated peak wind load coefficients on the stowed heliostat showed an inverse proportionality with the chord length of the heliostat mirror, which suggests that the coefficients could be optimised by increasing the size of the heliostat mirror relative to the sizes of the relevant eddies approaching the heliostat. The peak lift coefficient and peak hinge moment coefficient on the stowed heliostat could be reduced by as much as 23% by lowering the elevation axis height of the heliostat mirror by 30% in the simulated ABL. A significant linear increase of the peak wind load coefficients occurred at longitudinal turbulence intensities greater than 10% in the simulated ABL. Hence, the critical scaling parameters of the heliostat should be carefully considered depending on the turbulence characteristics of the site.Matthew Emes, Farzin Ghanadi, Maziar Arjomandi, Richard Kels
Diverse spatial, temporal, and sexual expression of recently duplicated androgen-binding protein genes in Mus musculus
BACKGROUND: The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization). RESULTS: It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible. We observed expression of six Abpa paralogues and five Abpbg paralogues in ten glands and other organs located predominantly in the head and neck (olfactory lobe of the brain, three salivary glands, lacrimal gland, Harderian gland, vomeronasal organ, and major olfactory epithelium). These Abp paralogues differed dramatically in their specific expression in these different glands and in their sexual dimorphism of expression. We also studied the appearance of expression in both late-stage embryos and postnatal animals prior to puberty and found significantly different timing of the onset of expression among the various paralogues. CONCLUSION: The multiple changes in the spatial expression profile of these genes resulting in various combinations of expression in glands and other organs in the head and face of the mouse strongly suggest that neofunctionalization of these genes, driven by adaptive evolution, has occurred following duplication. The extensive diversification in expression of this family of proteins provides two lines of evidence for a pheromonal role for ABP: 1) different patterns of Abpa/Abpbg expression in different glands; and 2) sexual dimorphism in the expression of the paralogues in a subset of those glands. These expression patterns differ dramatically among various glands that are located almost exclusively in the head and neck, where the sensory organs are located. Since mice are nocturnal, it is expected that they will make extensive use of olfactory as opposed to visual cues. The glands expressing Abp paralogues produce secretions (lacrimal and salivary) or detect odors (MOE and VNO) and thus it appears highly likely that ABP proteins play a role in olfactory communication
Turbulence length scales in a low-roughness near-neutral atmospheric surface layer
Published online: 14 Oct 2019.This paper investigated the integral length scales of turbulence in a low-roughness atmospheric surface layer (ASL), characterised by very smooth terrain in the Utah desert during near-neutral conditions, and evaluated the Engineering Sciences Data Unit (ESDU) 85020 and 86010 predictions for the turbulence length scales in a lowroughness ASL. The correlation integral method was used to estimate the integral length scales of the velocity components with longitudinal, lateral and vertical separations from sonic measurements on a vertical tower and spanwise array in the Surface Layer Turbulence and Environmental Science Test (SLTEST) field experiment. It was found that the longitudinal integral length scales calculated using near-neutral SLTEST data followed a logarithmic relationship with height proportional to the mean velocity profile with approximately constant integral time scale, however the sizes of the longitudinal components of the energy-containing eddies in the low-roughness flat terrain were 2–3 times smaller than those previously measured during field experiments in open country terrains. The calculated length scales with longitudinal separations over the very smooth terrain characteristics of the salt flats at Dugway were not consistent with those predicted by ESDU 85020. In contrast, the scaling of the lateral and vertical components of the three-dimensional turbulence structure with respect to the longitudinal component in the low-roughness ASL were consistent with similarity theory predictions in ESDU 86010 that the scaling ratios are independent of terrain roughness. Furthermore, this confirms the large dependence of the longitudinal turbulence length scales on the upstream terrain roughness and highlights the large variation of turbulence length scales observed at different low-roughness sites in the literature.Matthew J. Emes, Maziar Arjomandi, Richard M. Kelso and Farzin Ghanad
Identifying the cellular targets of drug action in the central nervous system following corticosteroid therapy
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
ACS Chemical Neuroscience, copyright © American Chemical Society after peer review and technical editing by the publisher.
To access the final edited and published work see http://dx.doi.org/10.1021/cn400167nCorticosteroid (CS) therapy is used widely in the treatment of a range of pathologies, but can delay production of myelin, the insulating sheath around central nervous system nerve fibers. The cellular targets of CS action are not fully understood, that is, "direct" action on cells involved in myelin genesis [oligodendrocytes and their progenitors the oligodendrocyte precursor cells (OPCs)] versus "indirect" action on other neural cells. We evaluated the effects of the widely used CS dexamethasone (DEX) on purified OPCs and oligodendrocytes, employing complementary histological and transcriptional analyses. Histological assessments showed no DEX effects on OPC proliferation or oligodendrocyte genesis/maturation (key processes underpinning myelin genesis). Immunostaining and RT-PCR analyses show that both cell types express glucocorticoid receptor (GR; the target for DEX action), ruling out receptor expression as a causal factor in the lack of DEX-responsiveness. GRs function as ligand-activated transcription factors, so we simultaneously analyzed DEX-induced transcriptional responses using microarray analyses; these substantiated the histological findings, with limited gene expression changes in DEX-treated OPCs and oligodendrocytes. With identical treatment, microglial cells showed profound and global changes post-DEX addition; an unexpected finding was the identification of the transcription factor Olig1, a master regulator of myelination, as a DEX responsive gene in microglia. Our data indicate that CS-induced myelination delays are unlikely to be due to direct drug action on OPCs or oligodendrocytes, and may occur secondary to alterations in other neural cells, such as the immune component. To the best of our knowledge, this is the first comparative molecular and cellular analysis of CS effects in glial cells, to investigate the targets of this major class of anti-inflammatory drugs as a basis for myelination deficits.British Neuro-pathological Society, North Staffordshire Medical Institute, and The University of Nottingham
Gut transcriptome reveals differential gene expression and enriched pathways linked to immune activation in response to weaning in pigs
Weaning represents one of the most critical periods in pig production associated with increase in disease risk, reduction in performance and economic loss. Physiological changes faced by piglets during the weaning period have been well characterised, however little is currently known about the underlying molecular pathways involved in these processes. As pig meat remains one of the most consumed sources of protein worldwide, understanding how these changes are mediated is critical to improve pig production and consequently sustainable food production globally. In this study, we evaluated the effect of weaning on transcriptomic changes in the colon of healthy piglets over time using an RNA-sequencing approach. The findings revealed a complex and coordinated response to weaning with the majority of genes found to be rapidly differentially expressed within 1 day post weaning. Multiple genes and pathways affected by weaning in the colon were associated with immune regulation, cell signalling and bacterial defence. NOD-like receptors, Toll-like receptor and JAK-STAT signalling pathways were amongst the pathways significantly enriched. Immune activation was evidenced by the enrichment of pathways involved in interferon response, cytokines interactions, oxidoreductase activities and response to microbial invasion. Biosynthesis of amino acids, in particular arginine, was also amongst the most enriched KEGG pathways in weaned pigs, reinforcing the critical role of arginine in gut homeostasis under stress conditions. Overall, transcriptomic and physiological results suggest that pigs going through the weaning transition undergo a transient period of inflammatory state with a temporary breakdown of barrier functions in the gut. These findings could provide valuable tools to monitor host response post weaning, and may be of particular relevance for the investigation and development of intervention strategies aimed to reduce antibiotic use and improve pig health and performance
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