Now showing items 1-20 of 8920

    • Computational fluid dynamics modelling of unconfined gas mixing of wastewater sludge in a full scale anaerobic digester

      Dapelo, Davide; Bridgeman, John (2015-09)
      In this paper, an Euler-Lagrange model for computational fluid dynamics was used to model a full-scale gas-mixed anaerobic digester. The flow profiles, local values of non-Newtonian viscosity and average shear rate were analysed. Recommendations to enhance the effectiveness of mixing were given. In particular, the gas mixing input power can be reduced without appreciable detrimental effects on the mixing effectiveness.
    • CEOs' regulatory foci and firm-level product innovativeness in competitive environments

      Adomako, Samuel (2017-06)
      Purpose: Using arguments from the regulatory focus and upper echelons theories, this paper aims to examine the impact of a chief executive officer’s (CEO’s) regulatory foci (i.e. promotion and prevention focus) on small- and medium-sized enterprises’ (SMEs’) level of innovativeness and how these relationships are jointly moderated by intense competition. Design/methodology/approach: The empirical analysis draws on survey data gathered from 257 SMEs in Ghana. Findings: The study findings indicate that a CEO’s level of promotion focus positively affects the firm’s engagement in innovation, while a CEO’s prevention focus is negatively associated with the firm’s innovativeness. The positive association between a CEO’s promotion focus and a firm’s innovativeness is enhanced under conditions of intense competition. Additionally, the negative relationship between prevention focus and firm-level innovativeness is attenuated under intense competition. Research limitations/implications: This study relied on a single informant and also used subjective measures for the dependent variable. As such, individual respondents might have biased perspectives on firm-level product innovativeness. Future studies may use multiple informants to examine the causal links of the variables. Practical implications: The study’s findings provide managers with a deeper understanding of how to achieve superior firm-level product innovation. The understanding of this issue can promote the development and maintenance of further entrepreneurial ventures in emerging economies. Originality/value: The paper has a strong theoretical value as it pioneers research on the effect of CEOs’ regulatory foci on firm-level innovativeness in competitive environments.
    • Analytical solution of suspended sediment concentration profile: relevance of dispersive flow term in vegetated channels

      Huai, W.; Yang, L.; Guo, Yakun (2020-07)
      Simulation of the suspended sediment concentration (SSC) has great significance in predicting the sediment transport rate, vegetation growth and the river ecosystem in the vegetated open channel flows. The present study focuses on investigating the vertical SSC profile in the vegetated open channel flows. To this end, a model of the dispersive flux is proposed in which the dispersive coefficient is expressed as partitioned linear profile above or below the half height of vegetation. The double-averaging method, i.e. time-spatial average, is applied to improve the prediction accuracy of the vertical SSC profile in the vegetated open channel flows. The analytical solution of SSC in both the submerged and the emergent vegetated open channel flows is obtained by solving the vertical double-averaging sediment advection-diffusion equation. The morphological coefficient, a key factor of the dispersive coefficient, is obtained by fitting the existing experimental data. The analytically predicted SSC agrees well with the experimental measurements, indicating that the proposed model can be used to accurately predict the SSC in the vegetated open channel flows. Results show that the dispersive term can be ignored in the region without vegetation, while the dispersive term has significant effect on the vertical SSC profile within the region of vegetation. The present study demonstrates that the dispersive coefficient is closely related to the vegetation density, the vegetation structure and the stem Reynolds number, but has little relation to the flow depth. With a few exceptions, the absolute value of the dispersive coefficient decreases with the increase of the vegetation density and increases with the increase of the stem Reynolds number in the submerged vegetated open channel flows.
    • Unaltered perception of suprathreshold contrast in early glaucoma despite sensitivity loss

      Bham, H.A.; Dewsbery, S.D.; Denniss, Jonathan (2020-07)
      PURPOSE. Glaucoma raises contrast detection thresholds, but our natural visual environment is dominated by high contrast that may remain suprathreshold in early to moderate glaucoma. This study investigates the effect of glaucoma on the apparent contrast of visible stimuli. METHODS. Twenty participants with glaucoma with partial visual field defects (mean age, 72 ± 7 years) and 20 age-similar healthy controls (mean age, 70 ± 7 years) took part. Contrast detection thresholds for Gabor stimuli (SD, 0.75°) of four spatial frequencies (0.5, 1.0, 2.0, and 4.0 c/deg) were first measured at 10° eccentricity, both within and outside of visual field defects for participants with glaucoma. Subsequently, the contrast of a central Gabor was matched to that of a peripheral Gabor with contrast fixed at two times or four times the detection threshold. Data were analyzed by linear mixed modelling. RESULTS. Compared with controls, detection thresholds for participants with glaucoma were raised by 0.05 ± 0.025 (Michelson units, ± SE; P = 0.12) and by 0.141 ± 0.026 (P < 0.001) outside and within visual field defects, respectively. For reference stimuli at two times the detection contrast, matched contrast ratios (matched/reference contrast) were 0.16 ± 0.039 (P < 0.001) higher outside compared with within visual field defects in participants with glaucoma. Matched contrast ratios within visual field defects were similar to controls (mean 0.033 ± 0.066 lower; P = 0.87). For reference stimuli at four times the detection contrast, matched contrast ratios were similar across all three groups (P = 0.58). Spatial frequency had a minimal effect on matched contrast ratios. CONCLUSIONS. Despite decreased contrast sensitivity, people with glaucoma perceive the contrast of visible suprathreshold stimuli similarly to healthy controls. These results suggest possible compensation for sensitivity loss in the visual system.
    • 5C analysis of the Epidermal Differentiation Complex locus reveals distinct chromatin interaction networks between gene-rich and gene-poor TADs in skin epithelial cells

      Poterlowicz, Krzysztof; Yarker, Joanne L.; Malashchuk, Igor; Lajoie, B.R.; Mardaryev, Andrei N.; Gdula, M.R.; Sharov, A.A.; Kohwi-Shigematsu, T.; Botchkarev, Vladimir A.; Fessing, Michael Y. (2017)
      Mammalian genomes contain several dozens of large (>0.5 Mbp) lineage-specific gene loci harbouring functionally related genes. However, spatial chromatin folding, organization of the enhancer-promoter networks and their relevance to Topologically Associating Domains (TADs) in these loci remain poorly understood. TADs are principle units of the genome folding and represents the DNA regions within which DNA interacts more frequently and less frequently across the TAD boundary. Here, we used Chromatin Conformation Capture Carbon Copy (5C) technology to characterize spatial chromatin interaction network in the 3.1 Mb Epidermal Differentiation Complex (EDC) locus harbouring 61 functionally related genes that show lineage-specific activation during terminal keratinocyte differentiation in the epidermis. 5C data validated by 3D-FISH demonstrate that the EDC locus is organized into several TADs showing distinct lineage-specific chromatin interaction networks based on their transcription activity and the gene-rich or gene-poor status. Correlation of the 5C results with genome-wide studies for enhancer-specific histone modifications (H3K4me1 and H3K27ac) revealed that the majority of spatial chromatin interactions that involves the gene-rich TADs at the EDC locus in keratinocytes include both intra- and inter-TAD interaction networks, connecting gene promoters and enhancers. Compared to thymocytes in which the EDC locus is mostly transcriptionally inactive, these interactions were found to be keratinocyte-specific. In keratinocytes, the promoter-enhancer anchoring regions in the gene-rich transcriptionally active TADs are enriched for the binding of chromatin architectural proteins CTCF, Rad21 and chromatin remodeler Brg1. In contrast to gene-rich TADs, gene-poor TADs show preferential spatial contacts with each other, do not contain active enhancers and show decreased binding of CTCF, Rad21 and Brg1 in keratinocytes. Thus, spatial interactions between gene promoters and enhancers at the multi-TAD EDC locus in skin epithelial cells are cell type-specific and involve extensive contacts within TADs as well as between different gene-rich TADs, forming the framework for lineage-specific transcription.
    • The application of PROMETHEE multi-criteria decision aid in financial decision making: case of distress prediction models evaluation

      Mousavi, Mohammad M.; Lin, J. (2020-11-30)
      Conflicting rankings corresponding to alternative performance criteria and measures are mostly reported in the mono-criterion evaluation of competing distress prediction models (DPMs). To overcome this issue, this study extends the application of the expert system to corporate credit risk and distress prediction through proposing a Multi-criteria Decision Aid (MCDA), namely PROMETHEE II, which provides a multi-criteria evaluation of competing DPMs. In addition, using data on Chinese firms listed on Shanghai and Shenzhen stock exchanges, we perform an exhaustive comparative analysis of the most popular DPMs; namely, statistical, artificial intelligence and machine learning models under both mono-criterion and multi-criteria frameworks. Further, we address two prevailing research questions; namely, "which DPM performs better in predicting distress?" and "will training models with corporate governance indicators (CGIs) enhance the performance of models?”; and discuss our findings. Our multi-criteria ranking suggests that non-parametric DPMs outperform parametric ones, where random forest and bagging CART are among the best machine learning DPMs. Further, models fed with CGIs as features outperform those fed without CGIs.
    • Alternative formats: Impact on student learning

      George, Sarah; Coussement, Katherine (2018-12-14)
      The national ebook audit highlighted the fact that many students who are print-impaired are also unable to use off-the-peg ebooks, so must rely on specific requests for texts in formats accessible to their particular needs (alternative formats or alt-formats) . We set out to investigate the scale of this issue and its effect on student learning.
    • Working Hard or Hardly Working: Use of Collaborative Working Space at the University of Bradford Library

      Field, Josie; George, Sarah; Khan, Reshma (2019-07)
      This book chapter reports on an observational study of working and non-working behaviour in the JB Priestley Library, University of Bradford.
    • Artificial intelligence in financial services: systemic implications and regulatory responses

      Kapsis, Ilias (2020-04)
      The article offers information on expansion of Artificial Intelligence (AI) in the financial services industry. Topics include Financial institutions see in it more opportunities for efficiency generation, improved profitability, and opportunities for differentiation for the building of competitive advantages; and develop, to improve reporting, and compliance processes.
    • Flexural performance of concrete beams reinforced with steel–FRP composite bars

      Ge, W.; Wang, Y.; Ashour, Ashraf F.; Lu, W.; Cao, D. (2020-05-16)
      Flexural performance of concrete beams reinforced with steel–FRP composite bar (SFCB) was investigated in this paper. Eight concrete beams reinforced with different bar types, namely one specimen reinforced with steel bars, one with fiber-reinforced polymer (FRP) bars and four with SFCBs, while the last two with hybrid FRP/steel bars, were tested to failure. Test results showed that SFCB/hybrid reinforced specimens exhibited improved stiffness, reduced crack width and larger bending capacity compared with FRP-reinforced specimen. According to compatibility of strains, materials’ constitutive relationships and equilibrium of forces, two balanced situations, three different failure modes and balanced reinforcement ratios as well as analytical technique for predicting the whole loading process are developed. Simplified formulas for effective moment of inertia and crack width are also proposed. The predicted results are closely correlated with the test results, confirming the validity of the proposed formulas for practical use.
    • Flexural Performance of Steel Reinforced ECC-Concrete Composite Beams Subjected to Freeze–Thaw Cycles

      Ge, W.; Ashour, Ashraf F.; Lu, W.; Cao, D. (2020-02-17)
      Experimental and theoretical investigations on the flexural performance of steel reinforced ECC-concrete composite beams subjected to freeze–thaw cycles are presented in this paper. Four groups of reinforced composite beams with different ECC height replacement ratios subject to 0, 50, 100 and 150 cycles of freeze–thaw were physically tested to failure. Experimental results show that the bending capacity decreases with the increase of freeze–thaw cycles regardless of ECC height replacement ratios. However, the ultimate moment, stiffness and durability of ECC specimens and ECC-concrete composite specimens are greater than those of traditional concrete specimens, owing to the excellent tensile performance of ECC materials. With the increase of ECC height, the crack width and average crack spacing gradually decrease. According to materials’ constitutive models, compatibility and equilibrium conditions, three failure modes with two boundary failure conditions are proposed. Simplified formulas for the moment capacity are also developed. The results predicted by the simplified formulas show good agreement with the experimental moment capacity and failure modes. A parametric analysis is conducted to study the influence of strength and height of ECC, amount of reinforcement, concrete strength and cycles of freeze–thaw on moment capacity and curvature ductility of ECC-concrete composite beams.
    • Sustaining the commitment to patient safety huddles: insights from eight acute hospital ward teams

      Montague, Jane; Crosswaite, Kate; Lamming, Laura; Cracknell, A.; Lovatt, A.; Mohammed, A. Mohammed (2019-11-14)
      Background: A recent initiative in hospital settings is the patient safety huddle (PSH): a brief multidisciplinary meeting held to highlight patient safety issues and actions to mitigate identified risks. Aim: The authors studied eight ward teams that had sustained PSHs for over 2 years in order to identify key contributory factors. Methods: Unannounced observations of the PSH on eight acute wards in one UK hospital were undertaken. Interviews and focus groups were also conducted. These were recorded and transcribed for framework analysis. Findings: A range of factors contributes to the sustainability of the PSH including a high degree of belief and consensus in purpose, adaptability, determination, multidisciplinary team involvement, a non-judgemental space, committed leadership and consistent reward and celebration. Conclusion: The huddles studied have developed and been shaped over time through a process of trial and error, and persistence. Overall this study offers insights into the factors that contribute to this sustainability.
    • pH Dependence of Acrylate-Derivative Polyelectrolyte Properties

      Swift, Thomas (2019-03-14)
      There are many polymers formed of acrylate monomers in existence. Here we interrogate four commonly-used examples and study how their solution properties are pH dependent, or how their state of ionisation can affect their solution properties. Poly(acrylic acid) and poly(methacrylic acid) are both polyelectrolytes, with ionisable functional groups that make them stimuli responsive, changing their hydrodynamic volume. Poly(acrylamide) is a mass-produced material used in a variety of industrial applications, often with an anionic and cationic co-monomer, which dictates both its efficacy and impact on the environment. Poly(N-isopropyl acrylamide) is a thermally responsive material with applications in smart bioengineering. In solution, these materials can interact with each other due to competing hydrogen bonding interactions. However, this interpolymer complexation is dependent on both the ionisation, and the conformational state, of the polymers involved. This review focuses on the results from fluorescence tagging and turbidimetric techniques.
    • Targeting the mesolithic: Interdisciplinary approaches to archaeological prospection inthe Brown Bank area, southern North Sea

      Missiaen, T.; Fitch, Simon; Muru, Merle; Harding, Rachel; Fraser, Andy; De Clercq, M.; Garcia Moreno, David; Versteeg, W.; Gaffney, Vincent L. (2020)
      This paper describes some results of the research undertaken over the Brown Bank area during recent (2018/2019) geoarchaeological surveys in the North Sea which included seismic imaging, shallow (vibro)coring and dredging. It examines the benefits of simultaneous high-resolution (0.5 – 1m) and ultra-high-resolution (10 – 20cm) seismic survey techniques and a staged approach to resolving the submerged Holocene landscape in the highest possible detail for the purpose of targeted prospecting for archaeological material from the Mesolithic landscape of Doggerland. The materials recovered from such surveys offer significantly greater information due to an enhanced understanding of the context in which they were recovered. The importance of this information cannot be understated archaeologically, as few locations on land provide the opportunity to recover archaeological finds in situ within preserved landscapes. Moreover, it allows offshore areas of potential human activity to be prospected with some certainty of success.
    • Interactive Fusion and Tracking For Multi‐Modal Spatial Data Visualization

      Elshehaly, Mai; Gračanin, D.; Gad, M.; Elmongui, H.G.; Matković, K. (2015-06)
      Scientific data acquired through sensors which monitor natural phenomena, as well as simulation data that imitate time‐identified events, have fueled the need for interactive techniques to successfully analyze and understand trends and patterns across space and time. We present a novel interactive visualization technique that fuses ground truth measurements with simulation results in real‐time to support the continuous tracking and analysis of spatiotemporal patterns. We start by constructing a reference model which densely represents the expected temporal behavior, and then use GPU parallelism to advect measurements on the model and track their location at any given point in time. Our results show that users can interactively fill the spatio‐temporal gaps in real world observations, and generate animations that accurately describe physical phenomena.
    • A FFLUX water model: flexible, polarizable and with a multipolar description of electrostatics

      Hughes, Zak E.; Ren, E.; Thacker, J.C.R.; Symons, B.C.B.; Silva, A.F.; Popelier, P.L.A. (2020-03)
      Key to progress in molecular simulation is the development of advanced models that go beyond the limitations of traditional force fields that employ a fixed, point charge‐based description of electrostatics. Taking water as an example system, the FFLUX framework is shown capable of producing models that are flexible, polarizable and have a multipolar description of the electrostatics. The kriging machine‐learning methods used in FFLUX are able to reproduce the intramolecular potential energy surface and multipole moments of a single water molecule with chemical accuracy using as few as 50 training configurations. Molecular dynamics simulations of water clusters (25–216 molecules) using the new FFLUX model reveal that incorporating charge‐quadrupole, dipole–dipole, and quadrupole–charge interactions into the description of the electrostatics results in significant changes to the intermolecular structuring of the water molecules.
    • Governance disclosure quality and market valuation of firms in UK and Germany

      Ullah, S.; Ahmad, S.; Akbar, Saeed; Kodwani, D.; Frecknall-Hughes, J. (Wiley, 2020)
      This study develops a 'comply or explain' index which captures compliance and quality of explanations given for non-compliance with the corporate governance codes in UK and Germany. In particular, we explain, how compliance and quality of explanations provided in non-compliance disclosures, and various other internal corporate governance mechanisms, affect the market valuation of firms in the two countries. A dynamic generalised method of moments (GMM) estimator is employed as the research technique for our analysis, which enabled us to control for the potential effects of endogeneity in our models. The findings of our content analysis suggest that firms exhibit significant differences in compliance, board independence and ownership structure in both countries. The 'comply or explain' index is positively associated with the market valuation of UK firms suggesting that compliance and quality governance disclosure is value relevant in the UK. Institutional blockholders' ownership is however, negatively associated with the market value of firms, which raises questions about the monitoring role of institutional shareholders in both countries. We argue that both compliance and explanations given for non-compliance are equally important, as long as valid reasons and justifications for non-compliance are provided by the reporting companies. These findings thus imply that the 'comply or explain' principle is working well and that UK and German companies could benefit from the flexibility offered by this principle. With respect to the role of board size, board independence, ownership structure, and institutional ownership of firms, this study offers policy implications.
    • PIA: More Accurate Taxonomic Assignment of Metagenomic Data Demonstrated on sedaDNA From the North Sea

      Gaffney, Vincent L.; Cribdon, B.; Ware, R.; Smith, O.; Allaby, R. (2020-04-03)
      Assigning metagenomic reads to taxa presents significant challenges. Existing approaches address some issues, but are mostly limited to metabarcoding or optimized for microbial data. We present PIA (Phylogenetic Intersection Analysis): a taxonomic binner that works from standard BLAST output while mitigating key effects of incomplete databases. Benchmarking against MEGAN using sedaDNA suggests that, while PIA is less sensitive, it can be more accurate. We use known sequences to estimate the accuracy of PIA at up to 96% when the real organism is not represented in the database. For ancient DNA, where taxa of interest are frequently over-represented domesticates or absent, poorly-known organisms, more accurate assignment is critical, even at the expense of sensitivity. PIA offers an approach to objectively filter out false positive hits without the need to manually remove taxa and so make presuppositions about past environments and their palaeoecologies.
    • Ewastools: Infinium Human Methylation BeadChip pipeline for population epigenetics integrated into Galaxy

      Murat, Katarzyna; Grüning, B.; Poterlowicz, P.W.; Westgate, Gillian E.; Tobin, Desmond J.; Poterlowicz, Krzysztof (Oxford Academic, 2020-05)
      Infinium Human Methylation BeadChip is an array platform for complex evaluation of DNA methylation at an individual CpG locus in the human genome based on Illumina’s bead technology and is one of the most common techniques used in epigenome-wide association studies. Finding associations between epigenetic variation and phenotype is a significant challenge in biomedical research. The newest version, HumanMethylationEPIC, quantifies the DNA methylation level of 850,000 CpG sites, while the previous versions, HumanMethylation450 and HumanMethylation27, measured >450,000 and 27,000 loci, respectively. Although a number of bioinformatics tools have been developed to analyse this assay, they require some programming skills and experience in order to be usable. Results We have developed a pipeline for the Galaxy platform for those without experience aimed at DNA methylation analysis using the Infinium Human Methylation BeadChip. Our tool is integrated into Galaxy (http://galaxyproject.org), a web-based platform. This allows users to analyse data from the Infinium Human Methylation BeadChip in the easiest possible way. Conclusions The pipeline provides a group of integrated analytical methods wrapped into an easy-to-use interface. Our tool is available from the Galaxy ToolShed, GitHub repository, and also as a Docker image. The aim of this project is to make Infinium Human Methylation BeadChip analysis more flexible and accessible to everyone.