Swarm optimization for adaptive phase measurements with low visibility

Adaptive feedback normally provides the greatest accuracy for optical phase measurements. New advances in nitrogen vacancy centre technology have enabled magnetometry via individual spin measurements, which are similar to optical phase measurements but with low visibility. The adaptive measurements that previously worked well with high-visibility optical interferometry break down and give poor results for nitrogen vacancy centre measurements. We use advanced search techniques based on swarm optimisation to design better adaptive measurements that can provide improved measurement accuracy with low-visibility interferometry, with applications in nitrogen vacancy centre magnetometry.Comment: 8 pages, 7 figures, comments welcom

Pathogenic Differences in Listeria monocytogenes 10403s and Cardiotropic Strains Grown under Aerobic and Anaerobic Conditions

Listeria monocytogenes is a gram-positive bacillus that is commonly associated with foodborne illness. It is a facultative intracellular pathogen responsible for causing the listeriosis infection in humans which is particularly dangerous to immunocompromised individuals. L. monocytogenes pathogenesis occurs through a series of complex interactions between host and bacterial cellular machinery. The wild-type strain as well as a cardiotropic strain with high affinity for infecting cardiac tissue were used to investigate pathogenesis in L. monocytogenes. Specifically, the Listeriolysin O protein that is critical for virulence was investigated. Aerobic and anaerobic growth environments as well as short-chain fatty acid supplementation were utilized to understand how growth conditions affect the pathogenic ability of L. monocytogenes

Effects of Solid Fat Content, Synthetic Antioxidants and Headspace Oxygen Reduction on the Rates of Oxidation in Surface and Total Lipids of Crackers

Unsaturated fats undergo a process known as oxidation by which they are degraded into undesirable compounds. Therefore it is important for food manufacturers to employ antioxidant strategies. Crackers were used as a model in these studies because of their dietary contribution to saturated, and because the properties of crackers are translatable to other low moisture foods. The objective of this thesis was to determine if there was a significant variance in rates of oxidation between surface and total lipids in crackers and how solid fat content, synthetic antioxidants, and reduction of headspace oxygen affect those rates. It was hypothesized that lipids on the surface of a cracker would be more prone to oxidation than those on the interior. Experiments consisted of treatments to monitor total lipid oxidation and surface lipid oxidation. In the first experiment, crackers were formulated with soy oils of varying solid fat content. The second experiment monitored the effects of two synthetic antioxidants, BHT and TBHQ. The third experiment involved flushing the headspace of cracker storage vials with different blends of nitrogen and oxygen to inhibit lipid oxidation. Overall, significant differences did not exist in the rates of oxidation between surface and interior lipids. The lower the solid fat content of an oil, the more prone it was to oxidation. Antioxidants of greater hydrophobicity have increased efficacy in low moisture foods. Greater than 70% oxygen reduction is necessary to impart any antioxidant effect on crackers

Martial the Book Poet: Contextu(r)alising the Flavian Poetry Book

This thesis explores how the reader is invited to read the books of Martial’s Epigrams, arguing that the epigrammatist has arranged the poems in his libelli in a specific order that rewards a sequential reading of the text from start to finish. Instead of viewing Martial as an anthologist who collated a series of occasional poems for their later publication, the thesis demonstrates that the poet showed awareness of his epigrams’ position within a larger ‘contexture’, and that he primes the reader throughout the Epigrams to envisage the books as thematically unified wholes. By viewing the Epigrams as a text to be read from beginning to end, rather than a text to be excerpted and anthologised, one can read each epigram in the wider context of its book, and better appreciate that book’s structural unity. Chapter one introduces the issues at stake in how one reads a book of epigrams, and provides the thesis’ methodological approach. Special attention is paid to the phenomenology of reading as a hermeneutic act, drawing together approaches to the Epigrams from classical scholarship as well as from reception and comic book theories to detail the method of ‘cumulative reading’ employed in the thesis. The second chapter then examines how Martial characterises the lector studiosus in his text, and how this depicted reader acts as a model for the actual reader to follow in their own sequential reading of the Epigrams. Chapter three focuses on Epigrams 7, demonstrating that the opening poems of the book establish the emperor Domitian as a thematic centrepiece around whom the rest of the book’s themes cluster. The fourth chapter also examines book 7, demonstrating how two different uses of watery motifs develop their individual thematic unity across the book, while also linking themselves back to the book’s opening imperial cycle to craft an overarching structural unity for the libellus. Chapter five then gives an overview of the larger structure of the Epigrams, arguing that the paratextual prose prefaces in books 1, 2, 8, 9, and 12 reinforce the individuality of the books they precede as well as establishing their own place within the wider corpus. Overall, this thesis puts the epigrammatic libellus back into the context of late first century AD book culture, emphasising that Martial paid attention not only to his epigrams’ position within their own books, but also their place within the wider corpus.The Arts and Humanities Research Council (AHRC

The fate of ethane in Titan's hydrocarbon lakes and seas

Ethane is expected to be the dominant photochemical product on Titan's surface and, in the absence of a process that sequesters it from exposed surface reservoirs, a major constituent of its lakes and seas. Absorption of Cassini's 2.2 cm radar by Ligeia Mare however suggests that this north polar sea is dominated by methane. In order to explain this apparent ethane deficiency, we explore the possibility that Ligeia Mare is the visible part of an alkanofer that interacted with an underlying clathrate layer and investigate the influence of this interaction on an assumed initial ethane-methane mixture in the liquid phase. We find that progressive liquid entrapment in clathrate allows the surface liquid reservoir to become methane-dominated for any initial ethane mole fraction below 0.75. If interactions between alkanofers and clathrates are common on Titan, this should lead to the emergence of many methane-dominated seas or lakes.Comment: Accepted for publication in Icaru

The classification of minor gait alterations using wearable sensors and deep learning

Objective: This paper describes how non-invasive wearable sensors can be used in combination with deep learning to classify artificially induced gait alterations without the requirement for a medical professional or gait analyst to be present. This approach is motivated by the goal of diagnosing gait abnormalities on a symptom-by-symptom basis, irrespective of other neuromuscular movement disorders the patients may be affected by. This could lead to improvements in treatment and offer a greater insight into movement disorders. Methods: In-shoe pressure was measured for 12 able-bodied participants, each subject to eight artificially induced gait alterations, achieved by modifying the underside of the shoe. The data were recorded at 100 Hz over 2520 data channels and were analyzed using the deep learning architecture and the long term short term memory networks. Additionally, the rationale for the decision-making process of these networks was investigated. Conclusion: Long term short term memory networks are applicable to the classification of the gait function. The classifications can be made using only 2 s of sparse data (82.0% accuracy over 96 000 instances of test data) from participants who were not a part of the training set. Significance: This paper provides potential for the gait function to be accurately classified using non-invasive techniques, and at more regular intervals, outside of a clinical setting, without the need for healthcare professionals to be present

PULSATORY MIXING OF LAMINAR FLOW USING BUBBLE-DRIVEN MICRO-PUMPS

Microfluidics differ from conventional fluid flows in that viscous forces dominate. As a result, microfluidics offer unprecedented control over fluid flows. The precise manipulation of fluids can be applied anywhere from healthcare in medical diagnostics to pharmaceutical companies miniaturizing reactions to reduce reagent consumption. In order to apply microfluidics as a comprehensive solution, unit operations must be performed – such as mixing, sorting, dilution, and much more. This work investigates mixing using thermal inkjet technology. Unlike macroscopic fluid flows with turbulence, transport phenomena become restricted in microfluidics. Active mixing approaches apply external forces (such as thermal or electric) to enhance mixing. This work focuses on a utilizing thermal inkjet technology as an active mixing technique. Y-shaped microfluidic channels have been built utilizing CNC and laser cutting manufacturing techniques. Fluid is delivered to each port via external syringe pumps. Each Y-shaped channel contains thermal inkjet (TIJ) resistors built using conventional microfabrication techniques. The resistors vaporize water and generate drive bubbles that act as active micro-mixers. The extent of mixing was characterized and studied in order to access the feasibility of TIJ resistors as integrated, compact micro-mixers in microfluidics

The Classification of Movement in Infants for the Autonomous Monitoring of Neurological Development

Neurodevelopmental delay following extremely preterm birth or birth asphyxia is common but diagnosis is often delayed as early milder signs are not recognised by parents or clinicians. Early interventions have been shown to improve outcomes. Automation of diagnosis and monitoring of neurological disorders using non-invasive, cost effective methods within a patient’s home could improve accessibility to testing. Furthermore, said testing could be conducted over a longer period, enabling greater confidence in diagnoses, due to increased data availability. This work proposes a new method to assess the movements in children. Twelve parent and infant participants were recruited (children aged between 3 and 12 months). Approximately 25 min 2D video recordings of the infants organically playing with toys were captured. A combination of deep learning and 2D pose estimation algorithms were used to classify the movements in relation to the children’s dexterity and position when interacting with a toy. The results demonstrate the possibility of capturing and classifying children’s complexity of movements when interacting with toys as well as their posture. Such classifications and the movement features could assist practitioners to accurately diagnose impaired or delayed movement development in a timely fashion as well as facilitating treatment monitoring