Clustering and networking among small independent hotels: developments over ten years

This paper reports on networking activities amongst a cluster of independent hotels with a view to analysing key variables in network development for SMEs. A comparative, longitudinal element is introduced by reference to an earlier study of the same phenomenon, ten years earlier. Of particular interest is the influence of various forms of social capital in the development of informal networks and the inter-play between co-operation and competition over time. Given the time gap between the two studies, the effect of sectoral changes on network development is also examined. The research revisits and extends a previous study of many of the same hotels which were investigated in 1995 over their formal and informal links that were found to be influenced by such factors across two classifications - the business as unit (proximity, perceptions of quality) and the individual respondent (personal social networks and ethnicity). Extending that analysis, social capital concepts and relevant references to embedded networks and kinship groups and co-operative game rules will be introduced in this paper. A highly concentrated population of small, independent hotels in Central London had been identified in the previous research project and it is from this sample that the current research drew and extended its own sample of hotels. With such a high number of hotels in the area a mixture of ‘snowball’ sampling and self-selection was successfully employed. Of the original 29 hotels, 22 have been re-interviewed and complemented by another 19. Of the remainder of the original sample, several had subsequently merged or failed to survive the intervening period. Face-to-face interviews were conducted with owner-managers in all cases using a structured questionnaire that replicated as much as possible of the original questionnaire, with both open and closed questions to allow some individual expression on relevant topics. The quantitative data obtained will be analysed using UCINET software to generate visual representations of networks alongside statistical and cluster analyses. Both academic and policy implications are likely to arise from this research, such as novel insights from such an unique periodic comparison of networks development, the influence of social capital on (formal and informal) network activities and the changing influence and consolidation of hotel groups through mergers and franchising

Shaping plasmon beams via the controlled illumination of finite-size plasmonic crystals

Plasmonic crystals provide many passive and active optical functionalities, including enhanced sensing, optical nonlinearities, light extraction from LEDs and coupling to and from subwavelength waveguides. Here we study, both experimentally and numerically, the coherent control of SPP beam excitation in finite size plasmonic crystals under focussed illumination. The correct combination of the illuminating spot size, its position relative to the plasmonic crystal, wavelength and polarisation enables the efficient shaping and directionality of SPP beam launching. We show that under strongly focussed illumination, the illuminated part of the crystal acts as an antenna, launching surface plasmon waves which are subsequently filtered by the surrounding periodic lattice. Changing the illumination conditions provides rich opportunities to engineer the SPP emission pattern. This offers an alternative technique to actively modulate and control plasmonic signals, either via micro- and nano-electromechanical switches or with electro- and all-optical beam steering which have direct implications for the development of new integrated nanophotonic devices, such as plasmonic couplers and switches and on-chip signal demultiplexing. This approach can be generalised to all kinds of surface waves, either for the coupling and discrimination of light in planar dielectric waveguides or the generation and control of non-diffractive SPP beams

Boundary effects in finite size plasmonic crystals: Focusing and routing of plasmonic beams for optical communications

Plasmonic crystals, which consist of periodic arrangements of surface features at a metal-dielectric interface, allow the manipulation of optical information in the form of surface plasmon polaritons. Here we investigate the excitation and propagation of plasmonic beams in and around finite size plasmonic crystals at telecom wavelengths, highlighting the effects of the crystal boundary shape and illumination conditions. Significant differences in broad plasmonic beam generation by crystals of different shapes are demonstrated, while for narrow beams, the propagation onto the smooth metal film is less sensitive to the crystal boundary shape. We show that by controlling the boundary shape, the size and the excitation beam parameters, directional control of propagating plasmonic modes and associated beam parameters such as angular beam splitting, focusing power and beam width can be efficiently achieved. This provides a promising route for robust and alignment-independent integration of plasmonic crystals with optical communication components

Integral closure of rings of integer-valued polynomials on algebras

Let $D$ be an integrally closed domain with quotient field $K$. Let $A$ be a torsion-free $D$-algebra that is finitely generated as a $D$-module. For every $a$ in $A$ we consider its minimal polynomial $\mu_a(X)\in D[X]$, i.e. the monic polynomial of least degree such that $\mu_a(a)=0$. The ring ${\rm Int}_K(A)$ consists of polynomials in $K[X]$ that send elements of $A$ back to $A$ under evaluation. If $D$ has finite residue rings, we show that the integral closure of ${\rm Int}_K(A)$ is the ring of polynomials in $K[X]$ which map the roots in an algebraic closure of $K$ of all the $\mu_a(X)$, $a\in A$, into elements that are integral over $D$. The result is obtained by identifying $A$ with a $D$-subalgebra of the matrix algebra $M_n(K)$ for some $n$ and then considering polynomials which map a matrix to a matrix integral over $D$. We also obtain information about polynomially dense subsets of these rings of polynomials.Comment: Keywords: Integer-valued polynomial, matrix, triangular matrix, integral closure, pullback, polynomially dense set. accepted for publication in the volume "Commutative rings, integer-valued polynomials and polynomial functions", M. Fontana, S. Frisch and S. Glaz (editors), Springer 201

Nets, relations and linking diagrams

In recent work, the author and others have studied compositional algebras of Petri nets. Here we consider mathematical aspects of the pure linking algebras that underly them. We characterise composition of nets without places as the composition of spans over appropriate categories of relations, and study the underlying algebraic structures.Comment: 15 pages, Proceedings of 5th Conference on Algebra and Coalgebra in Computer Science (CALCO), Warsaw, Poland, 3-6 September 201

A tale of two sites: how inflammation can reshape the microbiomes of the gut and lungs

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141495/1/jlb0943.pd

Outdoor Mosquito Control Using Odour-Baited Devices: Development and Evaluation of a Potential New Strategy to Complement Indoor Malaria Prevention Methods

A considerable effort is currently underway to develop a malaria vaccine based on live Plasmodium falciparum sporozoites. The first requisite of a sporozoite vaccine is the guarantee of parasite arrest prior to the onset of the pathogenic blood stage. Immunisation with genetically attenuated parasites (GAP) that arrest in the liver forms a promising approach. Work in this thesis describes the development and characterisation of a P. berghei Δb9Δslarp GAP that fully arrests in the liver. Immunisation of multiple mouse strains with low numbers of Δb9Δslarp GAP resulted in sterile protection. The Δb9Δslarp GAP is there- fore the leading GAP vaccine candidate. Work in this the- sis further describes the effect of varying the parameters of sporozoite inoculation on parasite liver load. These findings provide a rationale for the design of clinical trials aimed at the administration of live attenuated P. falciparum sporozoites

Multiple roles for FGF-3 during cranial nerve development in the chicken

FGF-3 has been implicated in the development of the hindbrain and otocyst in vertebrate embryos. Since the chicken embryo offers a favourable system in which to study the development of these structures, we have isolated and characterised cDNAs for chicken Fgf-3 and determined its pattern of expression in chick embryos from stage 3 (primitive streak) to stage 25 (early organogenesis). Within the developing cranial neural tube, Fgf-3 exhibits dynamic spatial and temporal expression. During extension of the head process, RNA is detected in the midline of the developing neural plate. In neurulating embryos, transcripts are observed initially in rhombomeres 4 and 5 of the hindbrain and later, in rhombomere 6. During hindbrain development, expression is lost from these rhombomeres, but becomes restricted to rhombomere boundaries, providing an intracellular marker which distinguishes a population of cells within boundary regions. Fgf-3 expression is elevated in ventral and medial boundary regions and is greatly reduced in dorsal parts. Studies of regenerating rhombomere boundaries show that Fgf-3 expression is induced in reforming boundaries when even-numbered rhombomere tissue is grafted next to odd, but not when like is juxtaposed to like. Fgf-3 disappears from boundary regions just prior to the loss of the morphological boundaries suggesting a boundary-associated function. Other sites of expression have also been identified. At early stages of development Fgf-3 is expressed in the epiblast and mesendoderm of the primitive streak, in mesoderm lateral to the streak and in Hensen's node. In older embryos transcripts are detected in the endoderm of the pharyngeal pouches, the ectoderm of the second and third pharyngeal arches and the stomodeum. Expression was also detected in the segmental plate and in the posterior half of the three most-recently generated somites

Quaternion-Octonion SU(3) Flavor Symmetry

Starting with the quaternionic formulation of isospin SU(2) group, we have derived the relations for different components of isospin with quark states. Extending this formalism to the case of SU(3) group we have considered the theory of octonion variables. Accordingly, the octonion splitting of SU(3) group have been reconsidered and various commutation relations for SU(3) group and its shift operators are also derived and verified for different iso-spin multiplets i.e. I, U and V- spins. Keywords: SU(3), Quaternions, Octonions and Gell Mann matrices PACS NO: 11.30.Hv: Flavor symmetries; 12.10-Dm: Unified field theories and models of strong and electroweak interaction