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Convective-scale hybrid data assimilation over the Maritime continent
Get PDFData assimilation is an important component of numerical weather prediction (NWP);
it is used to estimate realistic initial conditions. In recent years, hybrid data assimilation, which combines the traditional climatological representation of background
error covariances with an ensemble representation, has gained significant traction.
This thesis develops and applies hybrid ensemble-variational data assimilation to a
convective-scale tropical simplified model (ABC-DA) and an NWP system over the
western Maritime Continent (SINGV-DA) to explore its benefits and how it can be
better designed for the tropics.
Firstly, the hybrid ensemble-variational data assimilation approach (hybrid-En3DVar)
was implemented in ABC-DA. Generally, hybrid-En3DVar outperformed the traditional
3DVar data assimilation approaches. The improvements were sensitive to ensemble
size, and were less pronounced when the ensemble was very small. The results also
highlighted how the sub-optimal background error covariance model in 3DVar, which
uses geostrophic balance as a balance constraint, led to erroneous analysis increments
in meridional wind and negatively impacted the forecasts.
Secondly, the hybrid ensemble-variational data assimilation approach was implemented in SINGV-DA. Without proper tuning, the initial hybrid-En3DVar setup
had a relatively neutral impact compared to 3DVar. However, tuning the weightings for hybrid-En3DVar and time-shifting of ensemble perturbations were vital for
improving precipitation forecasts and forecast fits to radiosonde humidity and wind
compared to 3DVar. The results also highlighted how the autocovariance structures
varied between variables, including the presence of robust cross-correlation structures
between the moisture and temperature-related variables in the ensemble-derived background error matrix, which could have physical significance over the Maritime Continent.
Thirdly, the localisation aspect of En3DVar was modified to allow for variable-dependent localisation (prescribing different localisation length-scales for different variables) and selective multivariate localisation (knocking-out by localisation certain multi-variate error covariances) in ABC-DA. This was to address two limitations of traditional
ensemble-variational data assimilation approaches which were pertinent over the tropics. Using selective multivariate localisation was beneficial, particularly when covariances
associated with hydrostatic balance were retained and when zonal wind errors were de-coupled from the mass errors in the cross-covariances. The results also showed that
variable-dependent localisation could be beneficial if the localisation length-scales were
well-tuned for each variable. Both these enhancements within a pure EnVar framework
reduced the forecast root-mean-square errors by about 3-4% for zonal wind and mass
variables. These benefits may also apply to hybrid-En3DVar
Reading bodies and the fairy tale gaze
Get PDFIn this thesis, I will be asking the question: what does it mean to read? This is the question that
underpins my thinking and my readings. I will begin by reading the implications of the
relationship between the gaze and the body, as well as shifts in perspective and the lack which
is implicated in this split.
I will be engaging with a range of fairy tales from both Hans Christian Anderson and
Jacob and Wilhelm Grimm, and I will be reading this split and deferral throughout my fairy
tale analyses. I will also be engaging with texts that are not fairy tales, as these readings do not
have to be limited by the bounds of one ‘type’ of text. I will be thinking about the problem of
repetition as well as presence of absence, particularly in relation to disability theory discourse.
In the final section of this thesis, I will return to this notion of reading a body and what
this means in problematising identity. I will be reading further sections of ‘The Little Mermaid’
and returning to Derrida in exploring ideas of denuding. I will be continuing to read division
and deferral and returning to this notion of truth and revelation whilst asking ‘what does it
mean to read’? Finally, I will think about the consequences of my readings in this way. I want
to end on a reading to show that this is not just about fairy tales or literature or disability: this
is what people are thinking about and this is why this is important
Understanding the teaching-research nexus in the Saudi EFL context: Insights from an intercultural language teaching project
No full textExploring mucoadhesive and toxicological characteristics following modification of linear polyethylenimine with various anhydrides
Get PDFLinear polyethylenimine (L-PEI) has numerous applications, such as in pharmaceutical formulations, gene delivery, and water treatment. However, due to the presence of secondary amine groups, L-PEI shows a relatively high toxicity and low biocompatibility. Here, various organic anhydrides were used to modify L-PEI to reduce its toxicity and enhance its functionality. We selected methacrylic anhydride, crotonic anhydride, maleic anhydride, and succinic anhydride to modify L-PEI. The structure of the resulting derivatives was characterized using 1H NMR and FTIR spectroscopies, and their behavior in aqueous solutions was studied using turbidimetric and electrophoretic mobility measurements over a broad range of pHs. A fluorescence flow through method determined the mucoadhesive properties of the polymers to the bovine palpebral conjunctiva. Methacrylated L-PEI and crotonylated L-PEI showed strong mucoadhesive properties at pH 7.4, likely due to covalent bonding with mucin thiol groups. In contrast, maleylated and succinylated L-PEI were poorly mucoadhesive as the pH was above their isoelectric point, resulting in electrostatic repulsion between the polymers and mucin. The toxicity of these polymers was evaluated using in vivo assays with planaria and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell viability assay in human alveolar epithelial cells. Moreover, the irritancy of polymers was assessed using a slug mucosa irritation assay. The results demonstrated that anhydride modification mitigated the adverse toxicity effects seen for parent L-PEI
Consumer perception of risk towards new sustainable non-thermal food processing technologies: a cross-cultural study between Portugal, Germany, and the UK
Get PDFConsumers are interested in sustainable and safe food with positive sensory attributes, either minimally processed or incorporating sustainable processes. However, the introduction of new food technologies may generate
concern among consumers. This study aims to identify ways to decrease consumers' risk perception of new
technologies: High pressure, Non-thermal Plasma, Pulsed Electric Field, and Ultrasound. This cross-cultural study
was conducted in three contrasting countries: Portugal, Germany, and the United Kingdom, recruiting over 400
consumers per country. The survey presented twelve constructs based on the Ecological Framework, which was
used to predict perceived risk. Factors affecting such perception varied both for technologies and countries, as
shown by a multiple regression model. Food technology neophobia, perceived relative severity, and trust were
common factors across all countries. This study demonstrates that developing and producing new products using
non-thermal technologies should consider the country's consumers' risk perception factors
Identifying novel powdery mildew susceptibility and resistance genes in Fragaria × ananassa
Get PDFThe biotrophic fungal pathogen Podosphaera aphanis causes powdery mildew (PM) disease
on strawberry. Strawberry PM is a global problem, infecting all above ground plant organs.
The infection of PM leads to lower yields and unmarketable fruit and thus pathogen infections
result in high economic losses. Infection of the foliage can lead to a reduction in
photosynthesis, leading to decreased CO2 assimilation and ultimately a decrease in yield.
When the PM fungus infects strawberry reproductive tissue, it can cause misshapen or stunted
fruit. Control of PM disease is predominantly achieved by the application of fungicides;
however, overreliance on chemical application has led to the evolution of fungicide resistant
strains. Generating disease resistant cultivars offers a highly favourable solution to reduce the
impact of PM on strawberries. Thus far, there are no public, validated, large effect genetic
markers for use in improving PM disease resistance in strawberry. This project focused on
characterising the genetic components underlying tissue specific resistance to PM disease,
whilst ultimately identifying putative resistance genes. To achieve this goal, analysis was
conducted across different strawberry genotypes through a genome-wide association study
(GWAS) using phenotyping and genotyping data Multiple genetic loci associated with PM
resistance in foliage were identified using a GWAS, with several loci displaying a high effect
size of over 50%. Moreover, six stable Quantitative Trait Nucleotides were identified across
both years of assessment. In a separate experiment RNA sequencing was used to identify
differentially expressed genes in the presence of PM across three resistance types: tissue,
cultivar and ontogenic resistance. The RNA sequencing analysis revealed a diverse
immunogenetic resistance response associated with each different resistance type. Across
these resistance types, one gene (CAF1-11) was detected throughout, offering a promising
candidate for PM resistance. Another highly important trait that can lead to increased
strawberry production is fruit number, a component of yield. A GWAS was also conducted to
identify genetic loci that may be associated with fruit number. The analysis identified five genes
that may be involved in controlling fruit number. Finally, a genomic prediction approach was
used to determine the predictive accuracy associated with improving both strawberry PM
resistance and fruit number. This study has shown there is a large potential for using genomic
selection to increase cultivar foliar PM resistance; however, fruit PM resistance or fruit number
were not predicted to lead to an improvement in phenotype using a genomic prediction
approach. Overall, this study has identified multiple novel genes potentially associated with
PM resistance and fruit number. As such this work provides a greater understanding of the
complex mechanisms associated with these traits whilst offering a steppingstone towards the
development of genetic molecular markers for use in breeding elite strawberry lines
Share trading and product innovation: evidence from Chinese listed manufacturing firms
No full textThis study investigates whether and how boards of directors of Chinese listed
manufacturing firms utilise different share trading types as mechanisms for their firms’ product
innovation by employing in-depth interviews targeting board members of 25 listed manufacturing
firms in China from December 2021 to June 2022. The data analysis revealed that innovation, in
general, and product innovation, in particular, plays a critical role to these firms’ survival and
growth. Despite the variation in innovation investment across firms because of the impact of firms’
specific factors determined by their unique internal and external environment regarding
contingency theory, the innovation investment is still much lower than in developed countries with
less than 10% of total revenues. These firms have implemented share buyback, M&As, including
stock for stock mergers, and seasonal equity offerings, but they have not engaged with insider
trading recently because of their concerns with this practice’s legal liabilities and consequences on
firms’ survival. These firms have mostly carried out share buyback for equity incentive
programmes and for addressing the stock split problems instead of signalling, manipulating,
investing, compensating shareholders, or other purposes. Share buyback practice has not been
utilised as a direct mechanism for product innovation, but it has indirectly improved product
innovation through the incentive programme that mitigates agency conflicts, and thus improves
the management’s performance, including the R&D team members’ performance. These firms
have also implemented M&A and SEOs to boost innovation, but the degree to which M&A and
SEOs was used to support innovation is still limited. These firms have mostly used M&A to
acquire innovation capabilities abroad and only issued additional shares to raise funds for product
innovation when other sources of funds are unavailable. This study offers several significant
contributions to both theory and practice
Structure–activity relationships of DNA nanocarriers based on the amphipathic cell penetrating peptide transportan 10
Get PDFCell penetrating peptides (CPPs) have emerged as promising materials for the fabrication of synthetic nanovectors endowed with potential for improving the future landscape of gene therapy. A group of well-studied CPPs includes the transportan family, comprised of chimeric molecules combining segments derived from the antimicrobial wasp-venom mastoporan and the neuropeptide galanin. The success of these CPPs is supported by their effective use as the base for commercial peptide-based transfection reagents. Herein, we present a comprehensive study of the structure of peptiplexes formed between DNA fragments and transportan 10, a prototype example of amphipathic CPP. We conducted a thorough analysis of the self-aggregation of TP10, its secondary structure, and revealed details of its interaction with DNA. We employed atomic force microscopy-based nanospectroscopy to obtain single-particle data that revealed details of the conformations assumed by the peptide and DNA in the inner structure of nanoassemblies with different morphologies. Our structural results showed that TP10 exhibits self-aggregation capabilities and a strong propensity to assume α-helical conformations upon association with DNA strands. This behavior contrasts with that of prototype CPPs such as TAT-HIV and penetratin, potentially explaining why peptiplexes based on transportans demonstrate increased uptake compared to their cationic counterparts. Also, single-particle spectroscopy indicated that the secondary structure in peptiplexes is strongly dependent on the size and shape, reinforcing that controlled self-assembly is crucial for optimizing CPP-based nanotherapeutics. The peptiplexes were also evaluated for cell uptake efficiency and kinetics, revealing a logistic time–response increase in permeability, suggestive of cooperativeness. We anticipate that the findings presented here might contribute to refining structure–activity relationships of peptiplexes based on amphipathic CPPs, assisting the optimization of products based on this relevant class of CPPs with potential applications in therapeutic delivery systems
A cross-continental animal science perspective on milk fat research: what has happened and where are we heading?
No full textMilk is a fundamental food matrix that is widely consumed. Milk fat is important for producing dairy products such as butter, cream, cheese, and whole milk powder. Aside from flavour, it has been linked to human health and its chemistry can be modulated by various means towards more healthy fatty acid profile. Industry and stakeholders have different interests in milk fat, based on specific policies which reflect the type of research and funding initiatives currently performed in different countries. This position paper summarizes the current state-of-the-art with regards to milk fat research, industry, and stakeholder initiatives, and then highlights new developments based on information gathered from North America (United States and Mexico), Europe (United Kingdom, Spain, Italy, and Finland), Africa (Egypt), Asia (China and Bangladesh), and Oceania (New Zealand). South America is an important contributor to the dairy industry but will not be considered and thus this paper must be considered cross-continental rather than global. This manuscript intends to show a wide ‘picture’ of milk fat from different angles in different parts of the globe
Broadening the scope of anthropogenic influence in extreme event attribution
Get PDFAs extreme event attribution (EEA) matures, explaining the impacts of extreme events has risen to be a key focus for attribution scientists. Studies of this type usually assess the contribution of anthropogenic climate change to observed impacts. Other scientific communities have developed tools to assess how human activities influence impacts of extreme weather events on ecosystems and societies. For example, the disaster risk reduction (DRR) community analyses how the structure of human societies affects exposure, vulnerability, and ultimately the impacts of extreme weather events, with less attention to the role of anthropogenic climate change. In this perspective, we argue that adapting current practice in EEA to also consider other causal factors in attribution of extreme weather impacts would provide richer and more comprehensive insight into the causes of disasters. To this end, we propose a framework for EEA that would generate a more complete picture of human influences on impacts and bridge the gap between the EEA and DRR communities. We provide illustrations for five case studies: the 2021-2022 Kenyan drought; the 2013-2015 marine heatwave in the northeast Pacific; the 2017 forest fires in Portugal; Acqua Alta (flooding) events in Venice and evaluation of the efficiency of the Experimental Electromechanical Module (MoSE), an ensemble of mobile barriers that can be activated to mitigate the influx of seawater in the city; and California droughts and the Forecast Informed Reservoir Operations (FIRO) system as an adaptation strategy