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

Finite Temperature Casimir Effect and Dispersion in the Presence of Compactified Extra Dimensions

Finite temperature Casimir theory of the Dirichlet scalar field is developed, assuming that there is a conventional Casimir setup in physical space with two infinitely large plates separated by a gap R and in addition an arbitrary number q of extra compacified dimensions. As a generalization of earlier theory, we assume in the first part of the paper that there is a scalar 'refractive index' N filling the whole of the physical space region. After presenting general expressions for free energy and Casimir forces we focus on the low temperature case, as this is of main physical interest both for force measurements and also for issues related to entropy and the Nernst theorem. Thereafter, in the second part we analyze dispersive properties, assuming for simplicity q=1, by taking into account dispersion associated with the first Matsubara frequency only. The medium-induced contribution to the free energy, and pressure, is calculated at low temperatures.Comment: 25 pages, one figure. Minor changes in the discussion. Version to appear in Physica Script

EPS RHA Concrete Bricks – A New Building Material

Reuse of agricultural wastes and industrial by-products for building materials has been gaining popularity in the recent years. Agricultural waste material; namely rice husk ash (RHA), and industrial by-product; namely expanded polystyrene beads (EPS) are discarded in large amounts globally, causing increased environmental problems. Therefore, this paper introduces innovative efforts of the combined use of RHA and EPS wastes for the production of EPS RHA lightweight concrete bricks. Results showed that the commercial development of EPS RHA bricks is not only highly promising but also effectively sequestering the accumulation of these waste materials

Impaired interferon-γ responses, increased interleukin-17 expression, and a tumor necrosis factor–α transcriptional program in invasive aspergillosis

This article is available open access through the publisher’s website. Copyright @ 2009 Oxford University Press.Background - Invasive aspergillosis (IA) is the most common cause of death associated with fungal infection in the developed world. Historically, susceptibility to IA has been associated with prolonged neutropenia; however, IA has now become a major problem in patients on calcineurin inhibitors and allogenic hematopoetic stem cell transplant patients following engraftment. These observations suggest complex cellular mechanisms govern immunity to IA. Methods - To characterize the key early events that govern outcome from infection with Aspergillus fumigatus we performed a comparative immunochip microarray analysis of the pulmonary transcriptional response to IA between cyclophosphamide-treated mice and immunocompetent mice at 24 h after infection. Results - We demonstrate that death due to infection is associated with a failure to generate an incremental interferon-γ response, increased levels of interleukin-5 and interleukin-17a transcript, coordinated expression of a network of tumor necrosis factor–α-related genes, and increased levels of tumor necrosis factor–α. In contrast, clearance of infection is associated with increased expression of a number genes encoding proteins involved in innate pathogen clearance, as well as apoptosis and control of inflammation. Conclusion - This first organ-level immune response transcriptional analysis for IA has enabled us to gain new insights into the mechanisms that govern fungal immunity in the lung.The BBSRC, CGD Research Trust, and the MRC

Finite Temperature Casimir Effect in Randall-Sundrum Models

The finite temperature Casimir effect for a scalar field in the bulk region of the two Randall-Sundrum models, RSI and RSII, is studied. We calculate the Casimir energy and the Casimir force for two parallel plates with separation $a$ on the visible brane in the RSI model. High-temperature and low-temperature cases are covered. Attractiveness versus repulsiveness of the temperature correction to the force is discussed in the typical special cases of Dirichlet-Dirichlet, Neumann-Neumann, and Dirichlet-Neumann boundary conditions at low temperature. The Abel-Plana summation formula is made use of, as this turns out to be most convenient. Some comments are made on the related contemporary literature.Comment: 33 pages latex, 2 figures. Some changes in the discussion. To appear in New J. Phy

Casimir effect of electromagnetic field in D-dimensional spherically symmetric cavities

Eigenmodes of electromagnetic field with perfectly conducting or infinitely permeable conditions on the boundary of a D-dimensional spherically symmetric cavity is derived explicitly. It is shown that there are (D-2) polarizations for TE modes and one polarization for TM modes, giving rise to a total of (D-1) polarizations. In case of a D-dimensional ball, the eigenfrequencies of electromagnetic field with perfectly conducting boundary condition coincides with the eigenfrequencies of gauge one-forms with relative boundary condition; whereas the eigenfrequencies of electromagnetic field with infinitely permeable boundary condition coincides with the eigenfrequencies of gauge one-forms with absolute boundary condition. Casimir energy for a D-dimensional spherical shell configuration is computed using both cut-off regularization and zeta regularization. For a double spherical shell configuration, it is shown that the Casimir energy can be written as a sum of the single spherical shell contributions and an interacting term, and the latter is free of divergence. The interacting term always gives rise to an attractive force between the two spherical shells. Its leading term is the Casimir force acting between two parallel plates of the same area, as expected by proximity force approximation.Comment: 28 page

Origins of ferromagnetism in transition-metal doped Si

We present results of the magnetic, structural and chemical characterizations of Mn<sup>+</sup>-implanted Si displaying <i>n</i>-type semiconducting behavior and ferromagnetic ordering with Curie temperature,T<sub>C</sub> well above room temperature. The temperature-dependent magnetization measured by superconducting quantum device interference (SQUID) from 5 K to 800 K was characterized by three different critical temperatures (T*<sub>C</sub>~45 K, T<sub>C1</sub>~630-650 K and T<sub>C2</sub>~805-825 K). Their origins were investigated using dynamic secondary mass ion spectroscopy (SIMS) and transmission electron microscopy (TEM) techniques, including electron energy loss spectroscopy (EELS), Z-contrast STEM (scanning TEM) imaging and electron diffraction. We provided direct evidences of the presence of a small amount of Fe and Cr impurities which were unintentionally doped into the samples together with the Mn<sup>+</sup> ions, as well as the formation of Mn-rich precipitates embedded in a Mn-poor matrix. The observed T*<sub>C</sub> is attributed to the Mn<sub>4</sub>Si<sub>7</sub> precipitates identified by electron diffraction. Possible origins of and are also discussed. Our findings raise questions regarding the origin of the high ferromagnetism reported in many material systems without a careful chemical analysis

Conformal Mappings and Dispersionless Toda hierarchy

Let $\mathfrak{D}$ be the space consists of pairs $(f,g)$, where $f$ is a univalent function on the unit disc with $f(0)=0$, $g$ is a univalent function on the exterior of the unit disc with $g(\infty)=\infty$ and $f'(0)g'(\infty)=1$. In this article, we define the time variables $t_n, n\in \Z$, on $\mathfrak{D}$ which are holomorphic with respect to the natural complex structure on $\mathfrak{D}$ and can serve as local complex coordinates for $\mathfrak{D}$. We show that the evolutions of the pair $(f,g)$ with respect to these time coordinates are governed by the dispersionless Toda hierarchy flows. An explicit tau function is constructed for the dispersionless Toda hierarchy. By restricting $\mathfrak{D}$ to the subspace $\Sigma$ consists of pairs where $f(w)=1/\bar{g(1/\bar{w})}$, we obtain the integrable hierarchy of conformal mappings considered by Wiegmann and Zabrodin \cite{WZ}. Since every $C^1$ homeomorphism $\gamma$ of the unit circle corresponds uniquely to an element $(f,g)$ of $\mathfrak{D}$ under the conformal welding $\gamma=g^{-1}\circ f$, the space $\text{Homeo}_{C}(S^1)$ can be naturally identified as a subspace of $\mathfrak{D}$ characterized by $f(S^1)=g(S^1)$. We show that we can naturally define complexified vector fields \pa_n, n\in \Z on $\text{Homeo}_{C}(S^1)$ so that the evolutions of $(f,g)$ on $\text{Homeo}_{C}(S^1)$ with respect to \pa_n satisfy the dispersionless Toda hierarchy. Finally, we show that there is a similar integrable structure for the Riemann mappings $(f^{-1}, g^{-1})$. Moreover, in the latter case, the time variables are Fourier coefficients of $\gamma$ and $1/\gamma^{-1}$.Comment: 23 pages. This is to replace the previous preprint arXiv:0808.072

Geometric Phase in Eigenspace Evolution of Invariant and Adiabatic Action Operators

The theory of geometric phase is generalized to a cyclic evolution of the eigenspace of an invariant operator with $N$-fold degeneracy. The corresponding geometric phase is interpreted as a holonomy inherited from the universal connection of a Stiefel U(N)-bundle over a Grassmann manifold. Most significantly, for an arbitrary initial state, this geometric phase captures the inherent geometric feature of the state evolution. Moreover, the geometric phase in the evolution of the eigenspace of an adiabatic action operator is also addressed, which is elaborated by a pullback U(N)-bundle. Several intriguing physical examples are illustrated.Comment: Added Refs. and corrected typos; 4 page

SASS v.2.1: Anthropometric Spreadsheet and Database for the IRIS

This report is the user\u27s manual of SASS v.21, the Spreadsheet Anthropometric Scaling System (version 2.1). It describes the usage of SASS, a spreadsheet-like system which allows flexible interactive access to all anthropometric variables needed to size a computer-based human figure, described structurally by a PEABODY file. Data that may be accessed is organized into the following groups : segment dimension ( girth ), joint limits, center of mass, and strength, all of which work based on statistical population data. SASS creates generic computer-based human figures based on this data. SASS also is an anthropometric database and interactive query system that works upon anthropometric data of real individuals. Scaled computer-based human figures created by SASS can be displayed directly, and interactively changed, within the Jack software