VictorJuiz/thesis huggingface dataset:
Multisensory integration of redundant and complementary cues
Keywords: recalibration
cue combination
temporal estimates
multisensory integration
perception

During multisensory integration, information from distinct sensory systems that refers to the same physical event is combined. For example, the sound and image that an individual generates as s/he interacts with the world, will provide the nervous system with multiple cues which can be integrated to estimate the individual’s position in the environment. However, the information that is perceived through different sensory pathways/systems can be qualitatively different. The information can be redundant and describe the same property of an event in a common reference frame (i.e., the image and sound referring to the individual’s location), or it can be complementary. Combining complementary information can be advantageous in that it extends the range and richness of the information available to the nervous system, but can also be superfluous and unnecessary to the task at hand – i.e. olfactory cues about the individuals perfume can increase the richness of the representation but not necessarily aid in localisation. Over the last century or so, a large body of research has focused on different aspects of multisensory interactions at both the behavioural and neural levels. It is currently unclear whether the mechanisms underlying multisensory interactions for both type of cue are similar or not. Moreover, the evidence for differences in behavioural outcome, dependent on the nature of the cue, is growing. Such cue property effects possibly reflect a processing heuristic for more efficient parsing of the vast amount of sensory information available to the nervous system at any one time.
The present thesis assesses the effects of cue properties (i.e., redundant or complementary) on multisensory processing and reports a series of experiments demonstrating that the nature of the cue, defined by the task of the observer, influences whether the cues compete for representation as a result of interacting, or whether instead multisensory information produces an optimal increase in reliability of the event estimate. Moreover, a bridging series of experiments demonstrate the key role of redundancy in inferring that two signals have a common physical cause and should be integrated, despite conflict in the cues. The experiments provide insights into the different strategies adopted by the nervous system and some tentative evidence for possible, distinct underlying mechanisms.
Studies of magnetoresistance and hall sensors in semiconductors
Keywords: Hall effect
III-V compound semiconductor
Extraordinary Magnetoresistance

The design, fabrication and performance of an Extraordinary Magnetoresistance (EMR) and a Vertical Mesa Hall Sensor (VMHS) are studied.
EMR devices have been fabricated from a 2DEG InAs/GaSb structures which exhibit a low carrier density and high mobility that achieve the best performance. The general electrical magneto-transport properties are given. The experiments investigate mainly different metallic patterns, which are Rectangular, Triangular and Tip pattern between 4-300 K. Probe configurations and the enhancement of relative size of metallic patterns are described. EMR effect is due to current deflection around the metal-semiconductor interface. The results are metallic pattern dependent. Using finite element analysis, good agreement between experimental and theoretical results was found. The best performance sensor is a symmetrical metallic Tip pattern. It is enhanced by the length of the Tip’s point and the large metallic area. This pattern when combines with an asymmetrical probe configuration, exhibits the highest EMR of 900% at –0.275T measured by inner probes and the best sensitivity of 54Ω/T at room temperature.
The second study presents in-plane Hall effect sensors made from InSb. A simple device geometry has been used in which current flows in a plane perpendicular to the device surface. Device sensitivity depends on its geometry and a series of different contacts are used to investigate the geometry of the current flow distribution. The structures produced are only sensitive to the presence of one in-plane field component, and they also demonstrate good angular selectivity. Multi-electrodes were used to investigate biasing current from both mesa and substrate condition. We are able to examine the Hall voltage as a function of contact positions and also to create multiple VMHS. Offset reduction of devices has been achieved by moving the ground contacts to re-balance the current distribution under the mesa surface.
Quixotic exceptionalism: British and US co-narratives, 1713-1823
Keywords: Don Quixote
novel
transatlantic
exceptionalism
eighteenth century
quixote
quixotic
Cervantes

Scholars have long since identified a quixotic mode in fiction, acknowledging the widespread influence of Miguel de Cervantes' Don Quixote (1605-15) on subsequent texts. In most cases, “quixotic” signifies a preponderance of allusions to Don Quixote in a given text, such that most studies of “quixotic fictions” or “quixotic influence” are primarily taxonomic in purpose and in outcome: they name and catalogue a text or group of texts as “quixotic,” then argue that, by virtue of the vast and protean influence of Don Quixote, the quixotic mode in fiction is always divided, lacking any semblance of ideological consistency. I argue, however, that the very characteristics of Don Quixote that make him such an attractive literary model for such a broad range of narratives—his bookish idealism, his fixation on the upper-classed grandiosity of the lives of noble knights—also form the consistent, ideological groundwork of quixotism: the exceptionalist substitution of fictive idealism for material reality. By tracing the ways in which quixotes become mouthpieces for various exceptionalist arguments in eighteenth-century British and American texts, like Henry Fielding's Joseph Andrews (1742), Tobias Smollett's Launcelot Greaves (1760), Charlotte Lennox's The Female Quixote (1752), Hugh Henry Brackenridge's Modern Chivalry (1792-1815), and Royall Tyler's The Algerine Captive (1797), among others, I demonstrate the link between quixotism and exceptionalism, or between fictive idealism and the belief that one (or one's worldview) is an exception to the scrutiny of the surrounding world.
Royal sculpture in Egypt 300 BC - AD 220
Keywords: Hellenistic
Ptolemies
Ptolemaic
sculpture
Romans
Imperial
archaeology
Egyptian
statues
art

The aim of this thesis is to approach Ptolemaic and Imperial royal sculpture in Egypt dating between 300 BC and AD 220 (the reigns of Ptolemy I and Caracalla) from a contextual point of view. To collect together the statuary items (recognised as statues, statue heads and fragments, and inscribed bases and plinths) that are identifiably royal and have a secure archaeological context, that is a secure find spot or a recoverable provenance, within Egypt. I then used this material, alongside other types of evidence such as textual sources and numismatic material, to consider the distribution, style, placement, and functions of the royal statues, and to answer the primary questions of where were these statues located? what was the relationship between statue, especially statue style, and placement? And what changes can be identified between Ptolemaic and Imperial royal sculpture?
From analysis of the sculptural evidence, this thesis was able to create a catalogue of 103 entries composed of 157 statuary items, and use this to identify the different styles of royal statues that existed in Ptolemaic and Imperial Egypt and the primary spaces for the placement of such imagery, namely religious and urban space. The results of this thesis, based on the available evidence, was the identification of a division between sculptural style and context regarding the royal statues, with Egyptian-style material being placed in Egyptian contexts, Greek-style material in Greek, and Imperial-style statues associated with classical contexts. The functions of the statues appear to have also typically been closely related to statue style and placement. Many of the statues were often directly associated with their location, meaning they were an intrinsic part of the function and appearance of the context they occupied, as well as acting as representations of the monarchs. Primarily, the royal statues acted as a way to establish and maintain communication between different groups in Egypt.
Strategic placement of viscous dampers for seismic structural design
Keywords: viscous dampers
structural design
seismic

Seismic design with viscous devices is an effective means of dissipating seismic energy and protecting the main structural system from permanent damage. Despite numerous damper placement methods available, there lacks consensus on the best method, thus leaving design engineers without recommended placement strategies.
The purpose of this research is to investigate strategic placement of viscous dampers for seismic design and to offer design recommendations for placing dampers, vertically and horizontally. Five damper placement techniques were selected for investigation, including standard methods, Uniform and Stiffness Proportional damping, and advanced methods, the Simplified Sequential Search Algorithm (SSSA method), the Optimal Damper Placement for Minimum Transfer Functions (Takewaki method), and the Fully-stressed Analysis/Redesign method (Lavan A/R method). Effectiveness of the techniques for distributing linear fluid viscous dampers for two building examples was evaluated under a suite of twenty ground motions, two seismic hazard levels, and in terms of peak interstorey drifts, absolute accelerations, and residual drifts using nonlinear time history analysis. The advanced methods showed comparable performance based on performance indicators. Therefore, usability is recommended as the selection criteria. The Lavan A/R method was found to be the most effective and usable method. It is recommended that multiple design ground motions be used for the SSSA Mode and Lavan A/R methods as well as caution against removal of upper storey damping, which prompts susceptibility to larger roof drifts due to higher-mode effects.
Various brace-damper arrangements were explored to determine strategic horizontal damper placement. It was found that brace-damper arrangements with diagonals and multiple brace- damper sets per floor pose effective means of distributing the axial damper force and protecting the lower-storey columns from overstressing.
Behavioural testing of two nonlinear viscous devices was performed, and results were used to determine analytical models for the nonlinear fluid viscous and fluid spring devices based on fitted parameters. It was found that the stress-relaxation models better captured the nonlinearity of the devices than standard models but yielded only marginally decreased energy dissipation per cycle. Thus, it is recommended that standard models are adequate for analysis of damped structures with these nonlinear viscous devices.
Interactions of carbon nanotubes and lipid bilayers
Keywords: Molecular simulation
AFM
Carbon Nanotubes
Molecular dynamics
Lipid bilayers
MD
CNT
Lipids
Atomic force microscopy

The biological membrane, which is composed of a lipid bilayer embedded with numerous proteins, defines the cell boundary, separating the cell interior from the external environment. It serves as a gatekeeper and entry point for various molecular and ionic species. This thesis describes experimental and simulation studies of the interactions of carbon nanotubes (CNTs) with model membranes (lipid bilayers). The unique properties of CNTs make them ideal candidates for many nanotechnological applications. They can, however, pose a potential risk as toxins. While research into the positive benefits of CNTs continues, very little is known about their basic interactions with cellular components. It is particularly important to understand the interaction of CNTs with biological membranes, which form the primary physical barrier surrounding a cell.
Coarse grained molecular dynamics (MD) simulations and atomic force microscopy (AFM) have been used to study the interactions of CNTs and lipid bilayers. They are investigated in a controlled manner using MD simulations, while AFM has allowed the controlled approach-to-contact and insertion of CNTs into bilayers. A number of effects are reported, including lipid creep along the CNT and bilayer thickening upon contact. The robustness of this response is established using different force fields and lipid species.
The experimental results show an unusual reaction to mechanical indentation, and are further backed by MD simulations. The lipid bilayer response to multiple CNTs is studied and the effects of CNTs on bilayer conformation and lipid diffusion are reported. CNT internalisation from the solvent is observed in the simulations. Indeed, many of the observed phenomena are reminiscent of those known from the field of membrane protein. This project focuses on understanding the basic molecular interactions of CNTs with lipid bilayers and addresses the gap between experimental and computational work.
Development of high aspect ratio nano-focusing Si and diamond refractive x-ray optics using deep reactive ion etching
Keywords: Deep Reactive Ion Etching
Nano-focusing
CVD diamond
X-ray lens
Silicon

This thesis is devoted to the development of nano-focusing refractive optics for high energy X-rays using planar microelectronic technology. The availability of such optics is the key for the exploitation of high brilliance third and fourth generation X-ray sources. Advancements in the quality of optics available are commensurate with advancements in the fabrication technology. The fabrication process directly influences the quality and performance, so must be understood and controlled.
In the first part of this thesis, the development of high aspect ratio Si kinoform lenses is examined. It is shown that control of the re-entrance angle is critical for successful fabrication; in fact, a large re-entrance angle can destroy the lens during the fabrication process. Through an etch study, it was found that as aspect ratio increases, control of the re-entrance angle becomes harder. To control the re-entrance angle for very high aspect ratios, a novel approach based on sacrificial structures was proposed and initial results presented.
The second part is dedicated to an experimental study of refractive lenses made from diamond. Due to its low atomic number, relatively high density and very high thermal conductivity, diamond is one of the most desirable lens materials for refractive X-ray optics. However, due to its extreme hardness, it is very difficult to structure into a form suitable for X-ray lenses. To overcome this difficulty a Si moulding technique was used and focusing down to a 400 nm wide spot was achieved. Several obstacles were encountered and successfully overcome. The hardest obstacle was to obtain selective void-free filling in the Si moulds. Several methods were investigated. A method based on a sacrificial oxide layer and an Electrostatic Self-Assembly process was found to be the most useful. The approach discovered in this thesis is not limited to X-ray lenses, but can be applied to a wide variety of high aspect ratio MEMS requiring void-free diamond filling and smooth sidewalls.
Palladium- and copper-catalysed heterocycle synthesis
Keywords: heterocycle synthesis
Organic chemistry
organic synthesis
catalysis
palladium-catalysis
cinnolines
copper-catalysis

A number of privileged starting materials based on aryl halide frameworks have emerged that allow access to a variety of different heterocyclic scaffolds through judicious choice of reaction conditions. This work describes efforts to develop and extend the utility of two of these general heterocycle precursors - ortho-(haloalkenyl)aryl halides A and α-(ortho-haloaryl) ketones B - in conjunction with cascade reactions involving the construction of key carbon-heteroatom bonds via palladium or copper catalysis.
Chapter 1 entails an overview of the development of palladium- and copper-catalysed carbon-heteroatom bond forming processes. The application of these processes in heterocycle synthesis using ortho-(haloalkenyl)aryl halide and ortho-haloacetanilides/ α-(ortho-haloaryl) ketone precursors is also described.
Chapter 2 focuses on the development of a two-step synthesis of cinnolines using ortho-(haloalkenyl)aryl halides via intermediate protected dihydrocinnoline derivatives C.
Chapter 3 demonstrates how the inherent reactivity of protected dihydrocinnoline derivatives C can be harnessed to provide access to functionalised products. A brief target synthesis of a pharmaceutically-relevent cinnoline is also described.
Chapter 4 details attempts to develop a novel synthesis of benzothiophenes D from both ortho-(haloalkenyl)aryl halide and α-(ortho-haloaryl) ketone precursors.
Regulation of MITF and Brn2 in melanoma
Keywords: Melanoma
MITF
Cancer stem cells
Brn2
MAML1

Melanoma is the most aggressive skin cancer with high recurrence and low survival rate. In addition to genetic mechanisms, resistance also arises from phenotypic heterogeneity in which a proportion of cells, the so-called melanoma stem or initiating cells, survive therapy. Due to a lack of reliable markers, however, there is still debate about the existence of these cells in melanoma. Consistent with phenotypic heterogeneity, previous observations in our laboratory have demonstrated that cells in melanoma can reversibly segregate in vivo into different subpopulations with different properties, such as differentiation or increased invasive capacity (potentially attributed to the existence of de-differentiated stem-like cells). To characterise these cells, a dual reporter lentiviral system was engineered, expressing fluorescent proteins under cell stage/phenotype-specific promoters. The promoters for the transcription factors POU3F2 (Brn2) (to mark de-differentiated cells) and the microphthalmia-associated transcription factor (MITF) (to mark proliferating and differentiated cells) were chosen. Lentivirally-transduced cells were used to screen a library of kinase inhibitors for their potential to affect promoter activity in vitro. The RhoA/ROCK pathway, known to contribute to invasion and metastases, was identified to play a role in Brn2 promoter activity and exhibited differential effects on both the MITF and Brn2 promoters in 501mel and SKmel28 cell lines. Through investigation of other signalling pathways involved in melanoma metastasis, we also identified the co-activator Mastermind-like 1 (MAML1), previously reported to act in the Notch pathway, as an activator of the Brn2 promoter via the transcription factor TCF3, and the MITF promoter through the lymphoid-enhancer binding factor 1 (LEF1). The effects of MAML1 on Brn2 and MITF promoter activity were potentiated by β-catenin. These findings provide new opportunities for the identification of therapeutic targets to prevent metastases formation in melanoma.
Dissociable sources of uncertainty in perceptual decision making
Keywords: decision making
EEG
priming
perceptual adaptation
categorisation
gain control
fMRI
perception
summary representation

The natural world provides sensory systems with noisy and ambiguous information, which is often transformed into a more stable categorical percept. This thesis aims to investigate the nature of the neural representations in the visual system that support this transformation. To do so, we will employ a behavioural task that requires participants to average several independent sources of perceptual information. This task allows for the dissociation of two theoretically orthogonal sources of decision uncertainty: the mean distance of the perceptual information from a category boundary and the variability of the evidence under consideration. Behaviourally, both decreasing the mean distance to bound of information and increasing information variability are associated with increased errors and prolonged response times. We will present a computational model that can account for the independent behavioural effects of these two sources of uncertainty by assuming that categorical decisions are made on the basis of a probabilistic transformation of perceptual evidence. BOLD measurements demonstrate that these effects of mean and variability are supported by a partially dissociable network of brain regions. Electroencephalography demonstrates the differential influence of mean and variance in the pre- and post-decision period. Furthermore, we show that there is adaptation at the level of the perceptual representation to the information variance. Not only does this show that the visual system must represent information at the summary level, in addition to individual feature-based representation, but it also suggests that the costs associated with this form of perceptual uncertainty can be largely mitigated by the adoption of a more suitable representational range.
Investigation on the swelling mechanics of hydrogel tissue expanders using a skin-mimicking apparatus
Keywords: tissue expander
soft tissue
dermal tissue
implants
swelling
hydrogels

The concept of self-expanding hydrogel tissue expanders has opened a new pathway to the treatment of soft tissue defects. Traditionally designed to expand the skin, modifications to the swelling behaviour of these devices may lead to various new-found applications. Properties of poly(vinylpyrrolidone) /poly(methyl-methacrylate) (VP/MMA) hydrogel system such as the degree, rate, force generation, and anisotropic behaviour of swelling were investigated in this study as part of a preliminary understanding of the hydrogel material.
The swelling of hydrogel network is the balance between two main driving forces: 1) the relaxation of the gel network and 2) the osmotic diffusion of solvent via gel hydrophilicity. A direct relationship between the elastic modulus and the swelling pressure was found by measuring the swelling force over the hydration period. Despite reduction in the overall swelling ratio, gels with a larger modulus were observed to have a larger corresponding force generation. This is due to the straining of gels with higher cross-linking density. The results showed a maximum stress of 64.0 ± 3.2 kPa and 30.8 ± 1.5 kPa for 90:10 wt% and 99:1 wt% VP/MMA, respectively.
Specially modified anisotropic swelling gels were shown to have larger stress generation along the axis of directional swelling (~70-80 kPa). Limitation factors to the anisotropic modification are materialistic and geometrical. Shape-memory characteristics were found to be reduced at high compression ratio as a result of plastic deformation. Gels with slenderness ratio above 2.5 were evaluated to be susceptible to device slippage/buckling. These results provide useful design limitations for self-expanding tissue expanders.
The overall goal in creating a new testing system for self-swelling tissue expanders was achieved.A skin-mimicking apparatus was specially built to highlight the amount of skin expansion and simulate surface topography. Strain contours along the expanded skin were also plotted to represent skin tension. Prior to this study,these measurements were only possible under in vivo animal testing. The advantage in having this device is to support the prevention of related animal testing.