Pacific island economies : some observations on the economic consequences of natural disasters

The many difficult development problems faced by small resource-poor island countries such as those in the South Pacific, are all too familiar. Certainly, with small Pacific island countries the leading constraint is vulnerability to external shocks that can lead to economic collapse. Collapsibility can arise either from a sudden loss of export markets or a sharp decline in the terms of trade, and can lead to a drastic decline in GDP and export earnings and prolonged economic stagnation. Other major disturbances can arise from a political crisis ( e.g., Fiji 1987); the exhaustion of a major non-renewable export product (e.g., Kiribati 1979); crop destruction by insects or viral disease (e.g., Western Samoa 1993). As well, economic collapse can arise from periodic natural disasters such as cyclones and prolonged drought. Valuable insights into the economic collapsibility of small island countries in the Pacific can be found in recent works by Tisdell (1985), Kakazu (1985) and Fairbairn (1987). By means of simple growth models, these authors show that small island countries are incapable of sustainable growth because of vulnerability to external shocks, particularly a collapse in export demand combined with population growth. The analyses come out in favour of development policies that, among other things, encourage subsistence production as a sheet -anchor for these economies. The aim of this paper is to address another potential source of economic collapsibility - natural hazards particularly in the form of highly destructive tropical cyclones. The paper focuses on the recent incidence of tropical cyclones in the South Pacific, the severity of the devastation to these economies, and the impact on growth and policy responses. Particular attention is given to the consequences of a recent cyclone in Western Samoa and a simple theoretical model is presented showing the effects of cyclone devastation. The paper is essentially an exploratory study aimed at highlighting some of the major economic costs to small resource-poor island economies.peer-reviewe

Entrepreneurship and small business development in small islands

This paper reviews the limited literature on successful small business and entrepreneurship in small islands, with a focus on Pacific and European research. It argues that the notable specific contribution of this collection is its focus on tangible examples of successful island entrepreneurship, and the specific challenges towards entrepreneurship faced by island people. This approach is micro-oriented and very close to the actual human entrepreneurs that lead and shine by example. This is contrary to much received wisdom, which tends to be overshadowed by macro-structural and institutional approaches that emphasize chronic vulnerability.peer-reviewe

Estimating the Distribution of Random Parameters in a Diffusion Equation Forward Model for a Transdermal Alcohol Biosensor

We estimate the distribution of random parameters in a distributed parameter model with unbounded input and output for the transdermal transport of ethanol in humans. The model takes the form of a diffusion equation with the input being the blood alcohol concentration and the output being the transdermal alcohol concentration. Our approach is based on the idea of reformulating the underlying dynamical system in such a way that the random parameters are now treated as additional space variables. When the distribution to be estimated is assumed to be defined in terms of a joint density, estimating the distribution is equivalent to estimating the diffusivity in a multi-dimensional diffusion equation and thus well-established finite dimensional approximation schemes, functional analytic based convergence arguments, optimization techniques, and computational methods may all be employed. We use our technique to estimate a bivariate normal distribution based on data for multiple drinking episodes from a single subject.Comment: 10 page

Photon-axion mixing and ultra-high-energy cosmic rays from BL Lac type objects -- Shining light through the Universe

Photons may convert into axion like particles and back in the magnetic field of various astrophysical objects, including active galaxies, clusters of galaxies, intergalactic space and the Milky Way. This is a potential explanation for the candidate neutral ultra-high-energy (E>10^18 eV) particles from distant BL Lac type objects which have been observed by the High Resolution Fly's Eye experiment. Axions of the same mass and coupling may explain also TeV photons detected from distant blazars.Comment: Revtex 10 pages, 6 figures. V.2: QED dispersion effects taken into account; principal results unchanged. V3: misprints and sqrt(4*pi) factors in Gauss to eV conversion corrected; conclusions unchange

Aspectos computacionais da implementaçao da formulaçao diferencial aplicada à análise reológica de barragens de concreto

Neste artigo sáo apresentadas as formulaçóes integral e diferencial para a modelizacão matemática do problema reológico do concreto, assim como a correspondencia entre as duas formulaçoes. Sáo então apresentados exemplos numéricos visando uma comparacáo da eficiencia computacional de algoritmos baseados nos dois tipos de modelizaçao.Peer Reviewe

Black hole and brane production in TeV gravity: A review

In models with large extra dimensions particle collisions with center-of-mass energy larger than the fundamental gravitational scale can generate non-perturbative gravitational objects such as black holes and branes. The formation and the subsequent decay of these super-Planckian objects would be detectable in particle colliders and high energy cosmic ray detectors, and have interesting implications in cosmology and astrophysics. In this paper we present a review of black hole and brane production in TeV-scale gravity.Comment: 40 pages, 14 figures, submitted to the Int. Jou. Mod. Phys.

Geometrical CP violation in multi-Higgs models

We introduce several methods to obtain calculable phases with geometrical values that are independent of arbitrary parameters in the scalar potential. These phases depend on the number of scalars and on the order of the discrete non-Abelian group considered. Using these methods we present new geometrical CP violation candidates with vacuum expectation values that must violate CP (the transformation that would make them CP conserving is not a symmetry of the potential). We also extend to non-renormalisable potentials the proof that more than two scalars are needed to obtain these geometrical CP violation candidates.Comment: 8 pages, 2 figures. v2: table added, accepted by JHE

Observables in 3d spinfoam quantum gravity with fermions

We study expectation values of observables in three-dimensional spinfoam quantum gravity coupled to Dirac fermions. We revisit the model introduced by one of the authors and extend it to the case of massless fermionic fields. We introduce observables, analyse their symmetries and the corresponding proper gauge fixing. The Berezin integral over the fermionic fields is performed and the fermionic observables are expanded in open paths and closed loops associated to pure quantum gravity observables. We obtain the vertex amplitudes for gauge-invariant observables, while the expectation values of gauge-variant observables, such as the fermion propagator, are given by the evaluation of particular spin networks.Comment: 32 pages, many diagrams, uses psfrag