Heavy Fermion Quantum Effects in SU(2)_L Gauge Theory

We explore the effects of a heavy fermion doublet in a simplified version of the standard electroweak theory. We integrate out the doublet and compute the exact effective energy functional of spatially varying gauge and Higgs fields. We perform a variational search for a local minimum of the effective energy and do not find evidence for a soliton carrying the quantum numbers of the decoupled fermion doublet. The fermion vacuum polarization energy offsets the gain in binding energy previously argued to be sufficient to stabilize a fermionic soliton. The existence of such a soliton would have been a natural way to maintain anomaly cancellation at the level of the states. We also see that the sphaleron energy is significantly increased due to the quantum corrections of the heavy doublet. We find that when the doublet is slightly heavier than the quantum--corrected sphaleron, its decay is exponentially suppressed owing to a new barrier. This barrier exists only for an intermediate range of fermion masses, and a heavy enough doublet is indeed unstable.Comment: 30 pages LaTeX, 3 eps-figure

Searching for Quantum Solitons in a 3+1 Dimensional Chiral Yukawa Model

We search for static solitons stabilized by heavy fermions in a 3+1 dimensional Yukawa model. We compute the renormalized energy functional, including the exact one-loop quantum corrections, and perform a variational search for configurations that minimize the energy for a fixed fermion number. We compute the quantum corrections using a phase shift parameterization, in which we renormalize by identifying orders of the Born series with corresponding Feynman diagrams. For higher-order terms in the Born series, we develop a simplified calculational method. When applicable, we use the derivative expansion to check our results. We observe marginally bound configurations at large Yukawa coupling, and discuss their interpretation as soliton solutions subject to general limitations of the model.Comment: 27 pp., 7 EPS files; email correspondence to [email protected]

A phenomenological inquiry into the therapeutic aspects of tabletop roleplaying games

Table-top Role Playing Games (RPGs) have risen in popularity since their conception in the 1970’s. While some literature has explored their emergent psychological processes, very few studies have explicitly reflected on the therapeutic potential of these games, particularly from a phenomenological perspective. In this study, views, perceptions, and experiences of eight UK-based players were gathered through semi-structured interviews assisted by multi-modal diaries. These interviews were then transcribed and analysed through Interpretative Phenomenological Analysis (IPA). The analysis settled on two superordinate themes. ‘Symbolic Play’ consisted of two sub-themes: ‘Expression Through Play’, which captured participants’ idiosyncratic experiences of projecting fears, fantasies, desires, and taboos onto their characters; and ‘Working Through Difficulties’, which illustrates how players symbolically navigate their past experiences, or current difficulties through their character and the worlds they co-produce. The second superordinate theme ‘When Players Come Together’ also embodied two sub-themes: ‘Playing In Person Helps with Immersion’, which explored the experience of moving to online play from face-to-face as a result of the COVID-19 social restrictions, highlighting the importance of intimacy and physical proximity when playing in person; and ‘When Things Fall Apart: The Significance and Perils of the Group’, which examined conflicts the participants experienced as part of the role playing group, exploring what is counter-therapeutic in an attempt to provide an answer to what is therapeutic. I conclude by arguing that tabletop role-playing games play stage to profoundly therapeutic processes such as play, symbolism, containment, mirroring, and witnessing as they show us how players relate to themselves and the group. Strengths and limitations of the study are examined before arriving at some tentative recommendations regarding the value of role-playing vis-à-vis therapeutic growth, amongst other implications of the study. Reflexive commentary is offered throughout the thesis in an attempt to both bracket and pay attention to the phenomenology of the researcher, which has contributed to the double hermeneutic of sense-making in this research

Development of a bioinformatics framework for identification and validation of genomic biomarkers and key immunopathology processes and controllers in infectious and non-infectious severe inflammatory response syndrome

Sepsis is defined as dysregulated host response caused by systemic infection, leading to organ failure. It is a life-threatening condition, often requiring admission to an intensive care unit (ICU). The causative agents and processes involved are multifactorial but are characterized by an overarching inflammatory response, sharing elements in common with severe inflammatory response syndrome (SIRS) of non-infectious origin. Sepsis presents with a range of pathophysiological and genetic features which make clinical differentiation from SIRS very challenging. This may reflect a poor understanding of the key gene inter-activities and/or pathway associations underlying these disease processes. Improved understanding is critical for early differential recognition of sepsis and SIRS and to improve patient management and clinical outcomes. Judicious selection of gene biomarkers suitable for development of diagnostic tests/testing could make differentiation of sepsis and SIRS feasible. Here we describe a methodologic framework for the identification and validation of biomarkers in SIRS, sepsis and septic shock patients, using a 2-tier gene screening, artificial neural network (ANN) data mining technique, using previously published gene expression datasets. Eight key hub markers have been identified which may delineate distinct, core disease processes and which show potential for informing underlying immunological and pathological processes and thus patient stratification and treatment. These do not show sufficient fold change differences between the different disease states to be useful as primary diagnostic biomarkers, but are instrumental in identifying candidate pathways and other associated biomarkers for further exploration

Identification of Enterobacter sakazakii from closely related species: The use of Artificial Neural Networks in the analysis of biochemical and 16S rDNA data

BACKGROUND: Enterobacter sakazakii is an emergent pathogen associated with ingestion of infant formula and accurate identification is important in both industrial and clinical settings. Bacterial species can be difficult to accurately characterise from complex biochemical datasets and computer algorithms can potentially simplify the process. RESULTS: Artificial Neural Networks were applied to biochemical and 16S rDNA data derived from 282 strains of Enterobacteriaceae, including 189 E. sakazakii isolates, in order to identify key characteristics which could improve the identification of E. sakazakii. The models developed resulted in a predictive performance for blind (validation) data of 99.3 % correct discrimination between E. sakazakii and closely related species for both phenotypic and genotypic data. Three main regions of the partial rDNA sequence were found to be key in discriminating the species. Comparison between E. sakazakii and other strains also constitutively positive for expression of the enzyme α-glucosidase resulted in a predictive performance of 98.7 % for 16S rDNA sequence data and 100% for phenotypic data. CONCLUSION: The computationally based methods developed here show a remarkable ability in reducing data dimensionality and complexity, in order to eliminate noise from the system in order to facilitate the speed and reliability of a potential strain identification system. Furthermore, the approaches described are also able to provide valuable information regarding the population structure and distribution of individual species thus providing the foundations for novel assays and diagnostic tests for rapid identification of pathogens

Stabilization of air pollution control residues by utilizing geopolymerisation to produce secondary building materials

Incineration is a powerful waste management tool which is employed in many countries. However, air pollution control residues are a by-product produced as a result of flue gas treatment, a key requirement for incineration. Air pollution control residues are classified as hazardous waste and are becoming increasingly difficult to dispose of in the UK due to tightening legislation. Therefore recycling of air pollution control residues as secondary building materials is an attractive option. Geopolymerisation offers advantages with regards to stabilizing heavy metals and has been investigated here as a means to reducing leaching rates of key elements in air pollution control residues collected from three UK based incinerators. The role of soluble chloride phases was also investigated by pre-treating the air pollution control residues with a washing procedure. Geopolymerisation was found to immobilize metals such as Ba, Pb and Ni, however it did not positively affect the mobility of As, Sb and Se. Chloride leaching rates were also reduced although not to an acceptable level and the mobility of soluble chloride phases are one of the key challenges when attempting to reuse air pollution control residues

One-loop Effective Actions in Shape-invariant Scalar Backgrounds

The field-theoretic one-loop effective action in a static scalar background depending nontrivially on a single spatial coordinate is related, in the proper-time formalism, to the trace of the evolution kernel (or heat kernel) for an appropriate, one dimensional, quantum-mechanical Hamiltonian. We describe a recursive procedure applicable to these traces for shape-invariant Hamiltonians, resolving subtleties from the continuum mode contributions by utilizing the expression for the regularized Witten index. For some cases which include those of domain-wall-type scalar backgrounds, our recursive procedure yields the full expression for the scalar or fermion one-loop effective action in both (1+1) and (3+1)-dimensions.Comment: 11 pages, LaTeX2

A Numerical Investigation of the Effects of Classical Phase Space Structure on a Quantum System

We present a detailed numerical study of a chaotic classical system and its quantum counterpart. The system is a special case of a kicked rotor and for certain parameter values possesses cantori dividing chaotic regions of the classical phase space. We investigate the diffusion of particles through a cantorus; classical diffusion is observed but quantum diffusion is only significant when the classical phase space area escaping through the cantorus per kicking period greatly exceeds Planck's constant. A quantum analysis confirms that the cantori act as barriers. We numerically estimate the classical phase space flux through the cantorus per kick and relate this quantity to the behaviour of the quantum system. We introduce decoherence via environmental interactions with the quantum system and observe the subsequent increase in the transport of quantum particles through the boundary.Comment: 15 pages, 22 figure