Introduction to Quantum-Gravity Phenomenology

After a brief review of the first phase of development of Quantum-Gravity Phenomenology, I argue that this research line is now ready to enter a more advanced phase: while at first it was legitimate to resort to heuristic order-of-magnitude estimates, which were sufficient to establish that sensitivity to Planck-scale effects can be achieved, we should now rely on detailed analyses of some reference test theories. I illustrate this point in the specific example of studies of Planck-scale modifications of the energy/momentum dispersion relation, for which I consider two test theories. Both the photon-stability analyses and the Crab-nebula synchrotron-radiation analyses, which had raised high hopes of ``beyond-Plankian'' experimental bounds, turn out to be rather ineffective in constraining the two test theories. Examples of analyses which can provide constraints of rather wide applicability are the so-called ``time-of-flight analyses'', in the context of observations of gamma-ray bursts, and the analyses of the cosmic-ray spectrum near the GZK scale.Comment: 46 pages, LaTex. Based on lectures given at the 40th Karpacz Winter School in Theoretical Physic

Numerical entropy and phason elastic constants of plane random tilings with any 2D-fold symmetry

We perform Transition matrix Monte Carlo simulations to evaluate the entropy of rhombus tilings with fixed polygonal boundaries and 2D-fold rotational symmetry. We estimate the large-size limit of this entropy for D=4 to 10. We confirm analytic predictions of N. Destainville et al., J. Stat. Phys. 120, 799 (2005) and M. Widom et al., J. Stat. Phys. 120, 837 (2005), in particular that the large size and large D limits commute, and that entropy becomes insensible to size, phason strain and boundary conditions at large D. We are able to infer finite D and finite size scalings of entropy. We also show that phason elastic constants can be estimated for any D by measuring the relevant perpendicular space fluctuations.Comment: Accepted for publication in Eur. Phys. J.

Superconducting ground state of the two-dimensional Hubbard model: a variational study

A trial wave function is proposed for studying the instability of the two-dimensional Hubbard model with respect to d-wave superconductivity. Double occupancy is reduced in a similar way as in previous variational studies, but in addition our wave function both enhances the delocalization of holes and induces a kinetic exchange between the electron spins. These refinements lead to a large energy gain, while the pairing appears to be weakly affected by the additional term in the variational wave function.Comment: 2 pages, 1 figure, Proceedings of the M2S-HTSC-VII

Examining variation in the expression of tense/aspect to classify the Kikongo Language Cluster

In this article we examine variation in the expression of tense and aspect (TA) in 23 modern and two historical Bantu language varieties belonging to Guthrie’s B40, H10 and H30 groups in order to shed light on the internal classification of the Kikongo Language Cluster (KLC). We apply the Comparative Method to this specific set of morphological data to test a recent phylogenetic classification of the KLC. We identify eight widespread TA markers as shared retentions dating back to the period before the internal fragmentation of the KLC. Six of these are inherited from Proto‑Bantu. Two other markers go back to Proto‑Kikongoid and Proto‑Kikongo. They confirm that the KLC constitutes a discrete clade within West‑Coastal Bantu. We furthermore distinguish fourteen shared innovations that took place after the break‑up of the last common ancestor of the KLC. These innovations provide corroborating evidence for three phylogenetic subgroups within the KLC, namely East, South and West, and for the fact that the latter subgroup falls apart in two discrete genealogical subunits. They furthermore testify to the horizontal transmission of TA features between subgroups. Such language convergence often correlates with relatively recent historical developments within the Lower Congo region and contributed to the multilayered constitution of the KLC

The successful implementation of e-government transformation: A case study in Oman

The aim of this paper is to investigate, and to discuss the key critical factors that facilitate the successful implementation of E-government projects. The nature of this research is mainly qualitative. This investigation uses a single case study and data was mainly collected by means of semi-structured interviews and organisational documents from the Ministry of Higher Education in Oman. The research findings suggest that there are three paradigms which each include a set of factors that impacts the success of E-government success namely, organisational paradigm, technology paradigm and end-users paradigm. The authors believe that, this paper demonstrates an added value to the current literature on transformation of E-government and to E-government projects success, within the wider context of E-government implementation projects. Also the research will benefit organisations in the public sector, as it has identified main key success factors in E-government transformations and implementations

Smart hospital emergency system via mobile-based requesting services

In recent years, the UK’s emergency call and response has shown elements of great strain as of today. The strain on emergency call systems estimated by a 9 million calls (including both landline and mobile) made in 2014 alone. Coupled with an increasing population and cuts in government funding, this has resulted in lower percentages of emergency response vehicles at hand and longer response times. In this paper, we highlight the main challenges of emergency services and overview of previous solutions. In addition, we propose a new system call Smart Hospital Emergency System (SHES). The main aim of SHES is to save lives through improving communications between patient and emergency services. Utilising the latest of technologies and algorithms within SHES is aiming to increase emergency communication throughput, while reducing emergency call systems issues and making the process of emergency response more efficient. Utilising health data held within a personal smartphone, and internal tracked data (GPU, Accelerometer, Gyroscope etc.), SHES aims to process the mentioned data efficiently, and securely, through automatic communications with emergency services, ultimately reducing communication bottlenecks. Live video-streaming through real-time video communication protocols is also a focus of SHES to improve initial communications between emergency services and patients. A prototype of this system has been developed. The system has been evaluated by a preliminary usability, reliability, and communication performance study

Investigations into stability in the fig/ fig-wasp mutualism

Fig trees (Ficus, Moraceae) and their pollinating wasps (Chalcidoidea, Agaonidae) are involved in an obligate mutualism where each partner relies on the other in order to reproduce: the pollinating fig wasps are a fig tree’s only pollen disperser whilst the fig trees provide the wasps with places in which to lay their eggs. Mutualistic interactions are, however, ultimately genetically selfish and as such, are often rife with conflict. Fig trees are either monoecious, where wasps and seeds develop together within fig fruit (syconia), or dioecious, where wasps and seeds develop separately. In interactions between monoecious fig trees and their pollinating wasps, there are conflicts of interest over the relative allocation of fig flowers to wasp and seed development. Although fig trees reap the rewards associated with wasp and seed production (through pollen and seed dispersal respectively), pollinators only benefit directly from flowers that nurture the development of wasp larvae, and increase their fitness by attempting to oviposit in as many ovules as possible. If successful, this oviposition strategy would eventually destroy the mutualism; however, the interaction has lasted for over 60 million years suggesting that mechanisms must be in place to limit wasp oviposition. This thesis addresses a number of factors to elucidate how stability may be achieved in monoecious fig systems. Possible mechanisms include: 1) a parasitoidcentred short ovipositor hypothesis in Ficus rubiginosa, which suggests that a subset of flowers are out of reach to parasitoid ovipositors making these ovules the preferred choice for ovipositing pollinators and allowing seeds to develop in less preferred ovules; 2) the presence of third-party mutualists such as non-pollinating fig wasps (F. burkei) and patrolling green tree ants on the fig surface (F. racemosa) that limit pollinator and parasitoid oviposition respectively; and 3) selection on fig morphology which constrains the size (and therefore fecundity) of the associated pollinators. I discuss the lack of evidence for a single unifying theory for mutualism stability and suggest that a more likely scenario is the presence of separate, and perhaps multiple, stabilising strategies in different fig/ fig-wasp partnerships

Modeling of Induced Hydraulically Fractured Wells in Shale Reservoirs Using Branched Fractals

Imperial Users onl