Flux-Breaking of Gauge and Central Symmetries in the Hosotani Model

The purpose of this work is to examine the flux-breaking mechanism for breaking gauge symmetries in the context of the generalised Hosotani model. This model consists of either fermions or scalars (in one arbitrary representation of the gauge group) minimally coupled to Yang-Mills fields on a background spacetime of the form Rm x S1. In this model, the one loop effective potential can be explicitly calculated in terms of the non-trivial background field components satisfying Fmuv = 0 which exist in the circular dimension and therefore the particular breaking direction for any given case can be determined by minimising this potential. We begin in Chapter 1 by describing the flux-breaking mechanism. The group theory required for this analysis is then reviewed in chapter 2 before we go on to discuss the effective potential and its calculation in the generalised Hosotani model. We show in Chapters 5 and 6 that, for the case of either antiperiodic fermions or periodic scalars, the zero background is preferred as the global minimum of the potential and hence no symmetry breaking occurs. For periodic fermions or antiperiodic scalars, the zero background is destabilised by the matter field contribution to the potential. If such fields are in a representation whose congruency class does not contain the adjoint representation, then there exist non-zero backgrounds which preserve the gauge symmetry and are preferred as the global minima of the potential. Such non-zero backgrounds, however, lead to the matter fields having no zero modes on compactification of the theory to Rm and hence there is an apparent breaking of the central symmetry of the gauge group. If such destabilising fields are included in an adjoint class representation, then the zero background is found to be the only symmetry preserving background and. as this is eventually becomes a local maximum of the potential, the gauge symmetry must break. Examples illustrating this fact are given in numerical and graphical form. It is also found that the critical fermion number required to destabilise the zero background decreases as the spacetime dimension is increased, whereas the corresponding critical scalar number increases. This then leads to the conjecture that fermions will be more conducive to symmetry breaking than scalar fields in higher dimensional theories. An additional feature is found whereby scalars given a phase delta = pi/2 can break the gauge symmetry providing the representation containing them generates a group with Z2 centre. Examples of this type of breaking are also given, along with a discussion of permissible phases for the matter fields. Finally, Lagrangians containing more than one matter representation are examined in Chapter 7 in order to determine if the single representation features persist. It is found that the situation becomes more complicated, but symmetry breaking is again only found if destabilising fields in the appropriate representations are included. This leads to a general conjecture about the possibilities for flux breaking of gauge symmetries in any model, a conjecture which seems to be validated in a brief review of other toy models. An original example of an E6 model is also given, in which a realistic subgroup is obtained by flux breaking, provided that an upper limit is imposed on the number of fundamental representation fermion generations. We conclude by summarising the contributions made to the field in this thesis and we review the work of other authors on flux-breaking toy models

An improved novelty criterion for resource allocating networks

Online model order complexity estimation remains one of the key problems in neural network research. The problem is further exacerbated in situations where the underlying system generator is non-stationary. In this paper, we introduce a novelty criterion for resource allocating networks (RANs) which is capable of being applied to both stationary and slowly varying non-stationary problems. The deficiencies of existing novelty criteria are discussed and the relative performances are demonstrated on two real-world problems : electricity load forecasting and exchange rate prediction

Practical methods of tracking of nonstationary time series applied to real-world data

In this paper, we discuss some practical implications for implementing adaptable network algorithms applied to non-stationary time series problems. Two real world data sets, containing electricity load demands and foreign exchange market prices, are used to test several different methods, ranging from linear models with fixed parameters, to non-linear models which adapt both parameters and model order on-line. Training with the extended Kalman filter, we demonstrate that the dynamic model-order increment procedure of the resource allocating RBF network (RAN) is highly sensitive to the parameters of the novelty criterion. We investigate the use of system noise for increasing the plasticity of the Kalman filter training algorithm, and discuss the consequences for on-line model order selection. The results of our experiments show that there are advantages to be gained in tracking real world non-stationary data through the use of more complex adaptive models

Pseudotumor cerebri syndrome in childhood : incidence, clinical profile and risk factors in a national prospective population-based cohort study

Aim To investigate the epidemiology, clinical profile and risk factors of pseudotumor cerebri syndrome (PTCS) in children aged 1-16 years. Methods A national prospective population-based cohort study over 25 months. Newly diagnosed PTCS cases notified via British Paediatric Surveillance Unit (BPSU) were ascertained using classical diagnostic criteria and categorised according to 2013 revised diagnostic criteria. We derived national age, sex and weight-specific annual incidence rates and assessed effects of sex and weight category. Results We identified 185 PTCS cases of which 166 also fulfilled revised diagnostic criteria. The national annual incidence (95% CI) of childhood PTCS aged 1-16 years was 0.71 (0.57- 0.87) per 100,000 population increasing with age and weight to 4.18 and 10.7 per 100,000 in obese 12-15 year old boys and girls respectively. Incidence rates under 7 years were similar in both sexes. From 7 years onwards, the incidence in girls was double that in boys, but only in overweight (including obese) children. In 12-15 year old children, an estimated 82% of the incidence of PTCS was attributable to obesity. Two subgroups of PTCS were apparent: 168 (91%) cases aged from 7 years frequently presented on medication and with headache, and were predominantly female and obese. The remaining 17 (9%) cases under 7 years often lacked these risk factors and commonly presented with new onset squint. Conclusions This uniquely largest population-based study of childhood PTCS will inform the design of future intervention studies. It suggests that weight reduction is central to the prevention of PTCS

Perspectives on the Restatement (Fourth) Project

Good morning, everyone, and thank you all for coming. It is great to have this conversation, particularly with so many people who are already helpfully contributing to this project. As Bill said, I just wanted to say a little bit about the treaty prong of the project that was approved for consideration by the ALI a couple of years ago. First of all, I should note we get a lot of questions about whether or not we are addressing executive agreements and congressional executive agreements, in addition to Article II treaties. And the current answer is that we are not. We were originally tasked by the ALI to take up the status of Article II treaties in U.S. domestic law, and that is the current character of the project

Star Formation in the Most Distant Molecular Cloud in the Extreme Outer Galaxy: A Laboratory of Star Formation in an Early Epoch of the Galaxy's Formation

We report the discovery of active star formation in Digel's Cloud 2, which is one of the most distant giant molecular clouds known in the extreme outer Galaxy (EOG). At the probable Galactic radius of ~20 kpc, Cloud 2 has a quite different environment from that in the solar neighborhood, including lower metallicity, much lower gas density, and small or no perturbation from spiral arms. With new wide-field near-infrared (NIR) imaging that covers the entire Cloud 2, we discovered two young embedded star clusters located in the two dense cores of the cloud. Using our NIR and 12CO data as well as HI, radio continuum, and IRAS data in the archives, we discuss the detailed star formation processes in this unique environment. We show clear evidences of a sequential star formation triggered by the nearby huge supernova remnant, GSH 138-01-94. The two embedded clusters show a distinct morphology difference: the one in the northern molecular cloud core is a loose association with isolated-mode star formation, while the other in the southern molecular cloud core is a dense cluster with cluster-mode star formation. We propose that high compression by the combination of the SNR shell and an adjacent shell caused the dense cluster formation in the southern core. Along with the low metallicity range of the EOG, we suggest that EOG could be an excellent laboratory for the study of star formation processes, such as those triggered by supernovae, that occured during an early epoch of the Galaxy's formation. In particular, the study of the EOG may shed light on the origin and role of the thick disk, whose metallicity range matches with that of the EOG well.Comment: Accepted by The Astrophysical Journal (18 pages, 9 figures; a version w/full-resolution color figures is available at http://www.ioa.s.u-tokyo.ac.jp/~naoto/papers/apj.cl2_quirc/ms2p_final.pdf

Modelling 3D crack propagation in ageing graphite bricks of Advanced Gas-cooled Reactor power plant

In this paper, crack propagation in Advanced Gas-cooled Reactor (AGR) graphite bricks withageing properties is studied using the eXtended Finite Element Method (X-FEM). A parametric study for crackpropagation, including the influence of different initial crack shapes and propagation criteria, is conducted. Theresults obtained in the benchmark study show that the crack paths from X-FEM are similar to the experimentalones. The accuracy of the strain energy release rate computation in a heterogeneous material is also evaluatedusing a finite difference approach. Planar and non-planar 3D crack growth simulations are presented todemonstrate the robustness and the versatility of the method utilized. Finally, this work contributes to the better understanding of crack propagation behaviour in AGR graphite bricks and so contributes to the extension of the AGR plants’ lifetimes in the UK by reducing uncertainties

Open-coast sandy beaches and coastal dunes

Coastal ecosystems are centres of high biological productivity, but their conservation is often threatened by numerous and complex environmental factors. Citing examples from the major littoral habitats worldwide, such as sandy beaches, salt marshes and mangrove swamps, this text characterises the biodiversity of coastline environments and highlights important aspects of their maintenance and preservation, aided by the analysis of key representative species. Leaders in the field provide reviews of the foremost threats to coastal networks, including the effects of climate change, invasive species and major pollution incidents such as oil spills. Further discussion underscores the intricacies of measuring and managing coastline species in the field, taking into account the difficulties in quantifying biodiversity loss due to indirect cascading effects and trophic skew. Synthesising the current state of species richness with present and projected environmental pressures, the book ultimately establishes a research agenda for implementing and improving conservation practices moving forward. [Book Synopsis

BENO KOTRULJEVIĆ - UTEMELJITELJ HRVATSKE EKONOMSKE MISLI

Beno Kotruljević, bogati dubrovački trgovac iz prve polovine 15. stoljeća, utemeljitelj je hrvatske gospodarske misli i jedan od pionira ranog merkantilizma. Pored Juja Križanića je najznačajnije ime hrvatske ekonomske literature. Nastojeći dokazati značaj trgovine kao gospodarske djelatnosti, opisao je trgovačku praksu svog vremena i dao vlastita promišljanja o nekim bitnim pitanjima vezanim za trgovinu. U odnosu na raniju kanonističko-skolastičku gospodarsku misao, učinio je teorijske pomake u problematici trgovine, kamate, kredita i cijena. Iako je njegov rad "O trgovini i savršenom trgovcu" dosta istražen, uvijek je moguće naći u njemu nove doprinose. Ovaj rad pokušava otkriti nove spoznaje o istaknutom Dubrovčaninu