Tonga: Economic Survey 2009

The Tongan economy was well on its way to recovery from the effects of the riots and the oversized rise in public sector salaries of 2005 when it was hit by three new shocks: an inflation surge in 2007-08 due to price rises for imported food and fuels; the bursting of a bank credit 'bubble'; and the global financial crisis. Nevertheless, GDP growth has remained positive, as the subsistence sector is sheltered, and foreign financial assistance has supported construction activity and permitted an expansionary stance of fiscal policy. The macroeconomic picture is one of stability, with inflation back to low levels and the budget and the balance of payments showing overall surpluses. The economy remains vulnerable, however, and Tonga still does not appear to be within reach of a sustainable development path. The government will need-with the help of donor countries-to mobilise the private sector in key areas and tackle the main obstacles to development. Regional cooperation should also be strengthened, especially through consolidation and harmonisation. Pursuing these goals while maintaining the momentum for constitutional reform will be a major challenge

Atherosclerotic carotid plaque assessment with multidetector computed tomography angiography

This thesis evaluates the role of MDCT angiography in 1) the depiction of atherosclerotic disease and subsequent luminal stenosis in the arteries that supplies the brain with blood, and 2) the assessment of atherosclerotic plaque features that have been related to plaque vulnerability. The studies can be subdivided in three main categories: 1) optimization of data acquisition protocol, 2) validation studies, including assessment of the accuracy of MDCTA in comparison to histology and interobserver studies, and 3) clinical cross-sectional studies. From the first part of this thesis we can conclude that an optimal protocol for MDCT angiography of the supra-aortic arteries incorporates the use of 80 ml contrast material and a 40 ml saline bolus chaser, a craniocaudal scan direction, and in respect to atherosclerotic carotid plaque imaging a tube current of 120 kVp and an intermediate reconstruction algorithm. The second part of this thesis allows to conclude that MDCTA is capable of characterizing and quantifying plaque and plaque component areas in good correlation with histology. However, lipid core can only be adequately quantified in mildly calcified plaques, and in vivo assessment of atherosclerotic plaque and plaque component volumes is feasible with a moderate reproducibility. In addition we can conclude that, with MDCT angiography, intracranial carotid artery calcifications can reproducibly be quantified and that carotid plaque surface morphology can be assessed with a high reproducibility. In the third part of this thesis we evaluated the characteristics of possible MDCTA-assessed plaque parameters (the volume of intracranial calcifications, carotid plaque morphology, and carotid plaque volume and plaque component volumes). Associations were found with several cardiovascular risk factors. Some plaque parameters were related to the presence and type of cerebrovascular symptomatology. We conclude that atherosclerotic plaque parameters can be imaged adequately with MDCTA. These parameters seem to have a possible additional value, besides the degree of stenosis, as a marker of atherosclerotic disease and as predictor of (recurrent) ischemic cerebrovascular events

Saving irrigation water by accounting for windbreaks

Water for irrigation in the Canterbury region of New Zealand is becoming an increasingly precious commodity as it is in many other areas of the world. Adequate use of this resource will define the economical and environmental future of the region. Current irrigation systems, even under best management practices, over-apply water, as they do not account for spatial variability of crop water needs in fields. Over-application of water is wasteful and has environmental and economical repercussions. Water requirements are determined by crop evapotranspiration (ET). Key factors affecting ET in Canterbury are wind and solar radiation. Both of these are significantly affected by windbreaks, resulting in variability in ET and water requirements across a field. Understanding the variability in ET caused by windbreaks will enable for the correct application of water through precision irrigation systems. A theoretical model was developed to estimate savings in irrigation by accounting for windbreaks in the Canterbury region. Windbreaks reduce evapotranspiration and therefore crops/pasture behind windbreaks needs less water than those in other parts of the field. Results for a case study in Canterbury show that windbreaks can potentially reduce the annual on-farm water consumption by 10 to 20%, while still maintaining ideal crop/pasture yields. In the short term, the application of precision irrigation systems in fields with windbreaks can have farm level benefits of improved water use and reduced nitrogen/phosphorus leaching. In the long term this could translate directly into cost savings because of a potential decrease in energy used for irrigation (running pumps, etc.)

Behind the success of the quark model

The ground-state three-quark (3Q) potential $V_{\rm 3Q}^{\rm g.s.}$ and the excited-state 3Q potential $V_{\rm 3Q}^{\rm e.s.}$ are studied using SU(3) lattice QCD at the quenched level. For more than 300 patterns of the 3Q systems, the ground-state potential $V_{\rm 3Q}^{\rm g.s.}$ is investigated in detail in lattice QCD with $12^3\times 24$ at $\beta=5.7$ and with $16^3\times 32$ at $\beta=5.8, 6.0$. As a result, the ground-state potential $V_{\rm 3Q}^{\rm g.s.}$ is found to be well described with Y-ansatz within the 1%-level deviation. From the comparison with the Q-$\rm\bar Q$ potential, we find the universality of the string tension as $\sigma_{\rm 3Q}\simeq\sigma_{\rm Q\bar Q}$ and the one-gluon-exchange result as $A_{\rm 3Q}\simeq\frac12 A_{\rm Q\bar Q}$. The excited-state potential $V_{\rm 3Q}^{\rm e.s.}$ is also studied in lattice QCD with $16^3\times 32$ at $\beta=5.8$ for 24 patterns of the 3Q systems.The energy gap between $V_{\rm 3Q}^{\rm g.s.}$ and $V_{\rm 3Q}^{\rm e.s.}$, which physically means the gluonic excitation energy, is found to be about 1GeV in the typical hadronic scale, which is relatively large compared with the excitation energy of the quark origin. This large gluonic excitation energy justifies the great success of the simple quark model.Comment: Talk given at 16th International Conference on Particles and Nuclei (PANIC 02), Osaka, Japan, 30 Sep - 4 Oct 200

The radiation safety access control at GANIL and the RiB SPIRAL facility

International audienc

Strategic Debt: Evidence from Bertrand and Cournot Competition

We investigate how competitive behavior affects the capital structure of a firm. Theory predicts that the impact of different types of output market uncertainty (in particular, unanticipated shocks in demand and costs) on a firm’s leverage depends on the type of competition in an industry. We test these predictions in a sample of U.S. manufacturing firms by classifying firms into Cournot competition (strategic substitutes), and Bertrand competition (strategic complements). We show that demand uncertainty is positively related to leverage for firms in both the Cournot and the Bertrand sample. Cost uncertainty has a significantly positive impact on the leverage of Cournot firms, but plays a negligible role for Bertrand firms. Our results support the strategic use of debt and highlight the role of firms’ competitive behavior in the product market in their capital structure decisions

A bootstrap-based method to achieve optimality on estimating the extreme-value index

Estimators of the extreme-value index are based on a set of upper order statistics. We present an adaptive method to choose the number of order statistics involved in an optimal way, balancing variance and bias components. Recently this has been achieved for the similar but somewhat less involved case of regularly varying tails (Drees and Kaufmann(1997); Danielsson et al.(1996)). The present paper follows the line of proof of the last mentioned paper

Wave effect in gravitational lensing by a cosmic string

The wave effect in the gravitational lensing phenomenon by a straight cosmic string is investigated. The interference pattern is expressed in terms of a simple formula. We demonstrate that modulations of the interfered wave amplitude can be a unique signature of the wave effect. We briefly mention a possible chance of detecting the wave effect in future gravitational wave observatories.Comment: 4 pages, 1 figur

Removal Of Cyanobacteria Toxins From Drinking Water By Adsorption On Activated Carbon Fibers

Natural fibers from macadamia nut shell, dried coconut shell endocarp, unripe coconut mesocarp, sugarcane bagasse and pine wood residue were used to prepare activated carbon fibers (ACF) with potential application for removing microcystins. The ACF from pine wood and sugar cane bagasse were used to remove [D-Leucine1 MCYST-LR from water. After 10 minutes of contact time, more than 98% of toxin was removed by the ACF. The microcystin adsorption monolayer, qm, in the ACF recovered 200 and 161 μg.mg-1, with the Langmuir adsorption constant, KL, of 2.33 and 1.23 L.mg-1. Adsorption of [D-Leucine1]MCYST-LR in continuous process was studied for a fixed-bed ACF prepared from coconut shell and sugar cane bagasse and for two commercial activated carbon samples from treatment water plants of two Brazilian hemodialysis centers. Saturation of the beds occurred after 80 to 320 minutes, and the adsorption capacity for that toxin varied from 4.11 to 12.82 μg.mg-1.113371380Honda RY, Mercante CTJ, Vieira JMS, Esteves KE, Cabianca MAA, Azevedo MTP. Cianotoxinas em pesqueiros da região metropolitana de São Paulo. In: Esteves KE, Sant'Anna CL. (Org.). Pesqueiros sob uma visão integrada de meio ambiente, saúde pública e manejo. São Carlos: Rima2006. p. 105-120Sant'anna, C.L., Azevedo, M.T.D., Contribution to the knowledge of potentially toxic Cyanobacteria from Brazil (2000) Nova Hedwigia, 71 (3-4), pp. 359-385Landsberg, J.H., The effects of harmful algal blooms on aquatic organisms (2002) Reviews in Fisheries Science, 10 (2), pp. 113-390Hoffman, J.R.H., Removal of Microcystis toxins in water purification process (1976) Water S.A, 2 (2), pp. 58-60Keijola, A.M., Himberg, K., Esala, A.L., Sivonen, K., Hiisvirta, L., Removal of cyanobacterial toxins in water-treatment processes - laboratory and pilot-scale experiments (1988) Toxicity Assessment, 3 (5), pp. 643-656Falconer, I.R., Runnegar, M.T.C., Buckley, T., Huyn, V.L., Bradshaw, P., Use of powdered and granular activated carbon to remove toxicity from drinking water containing cyanobacterial toxins (1989) Journal American Water Works Association, 18 (2), pp. 102-105Himberg, K., Keijola, A.M., Hiisvirta, L., Pyysalo, H., Sivonen, K., The effect of water treatment processes on the removal of hepatotoxins from Microcystis and Oscillatoria cyanobacteria: A laboratory study (1988) Water Research, 23 (8), pp. 979-984Ministério do Desenvolvimento, Indústria e Comércio Exterior do Brasil (2005) Importation and exportation of activated carbon from Brazil, , http://aliceweb.desenvolvimento.gov.br, BRASIL, Available from:, Accessed on: JanuaryMatthiensen, A., Beattie, K.A., Yunes, J.S., Kaya, K., Codd, G.A., D-Leu(1) microcystin-LR, from the cyanobacterium Microcystis RST 9501 and from a Microcystis bloom in the Patos Lagoon estuary, Brazil (2000) Phytochemistry, 55 (5), pp. 383-387Oliveira, A.C.R., Magalhães, S.V.F., Soares, R.M., Azevedo, S.M.F.O., Influence of drinking water composition on quantitation and biological activity of dissolved microcystin (Cyanotoxin) (2005) Environmental toxicology, 20 (2), pp. 126-130Albuquerque-Jr, E.C., Mendez, M.O., Coutinho, A.R., Franco, T.T., Production and characterization of activated carbon from Brazilian agricultural residues (2005) Proceedings of the third Brazilian Carbono Congress, pp. 401-410. , Castro AT ed, November 7-11Rio de Janeiro, Brazil. Rio de Janeiro: Department of Science and Thecnology and Thecnological Center of the Brazilian Army;Webb, P.A., Orr, C., Surface area and pore structure by gas adsorption (1997) Analytical methods in fine particle technology, , Atlanta: Micromeritics Instrument Corp. Atlanta;, 301 pKuroda EK, Albuquerque-Jr EC, Di Bernardo L, Trofino JC. Caracteriza&ão e escolha do tipo de carvão ativado a ser empregado no tratamento de aguas contendo microcistinas. In: Brazilian Association of Sanitation and Environmental Engineering (ed.). Brazilian Environmental Sanitation: utopia or reality? Proceedings of the twentieth third Brazilian Congrees of Sanitary and Environmental Engineering2005 18-23Mato Grosso, Brazil. Campo Grande: Brazilian Association of Sanitary and Environmental Engineering2005. p. 1-10Albuquerque-Jr EC, Melo LFC, Franco TT. Use of solid-phase extraction, high-performance liquid chromatography, and MALDI-TOF identification for [D-Leu1]MCYST-LR analysis in treated water: Validation of the analytical methodology. Canadian Journal of Analytical Sciences & Spectroscopy. 200752(1). (in press)Ruthven, D.M., Goddard, M., Sorption and diffusion of C-8 aromatic-hydrocarbons in faujasite type zeolites. 1. equilibrium isotherms and separation factors (1986) Zeolites, 6 (4), pp. 275-282Ho, Y.S., McKay, G., Pseudo-second order model for sorption processes (1999) Process. Biochem, 34 (5), pp. 451-465Ho, Y.S., McKay, G., Kinetic models for the sorption of dye from aqueous solution by wood (1998) J. Environ. Sci. Health Part B: Process Safety Environ. Protect, 76 (B2), pp. 183-191Low, M.J.D., Kinetics of chemisorption of gases on solids (1960) Chem. Rev, 60 (3), pp. 267-312Chien, S.H., Clayton, W.R., Application of Elovich equation to the kinetics of phosphate release and sorption in soils (1980) Soil Sci. Soc. Am. J, 44 (2), pp. 265-268Santos, E.S., Guirardello, R., Franco, T.T., Preparative chromatography of xylanase using expanded bed adsorption (2002) Journal of chromatography A, 944 (1-2), pp. 217-224Barros, M.A.S.D., Zola, A.S., Arroyo, P.A., Aguiar, E.F.S., Tavares, C.R.G., Equilibrium and dynamic ion exchange studies of Cr3+ on zeolites NaA and NaX (2002) Acta Scientiarum, 24 (6), pp. 1619-1625Geankoplis, C.J., (2003) Transport Processes and Separation Process Principles, , 4 ed. USA: PTR Prentice Hall;Quinlivan, P.A., Li, L., Knappe, D.R.U., Effects of activated carbon characteristics on the simultaneous adsorption of aqueous organic micropollutants and natural organic matter (2005) Water Research, 39 (8), pp. 1663-1673Donati, C., Drikas, M., Hayes, R., Newcombe, G., Microcystin-LR adsorption by powdered activated carbon (1994) Water Research, 28 (8), pp. 1735-1742Pendleton, P., Schumann, R., Wong, S.H., Microcystin-LR adsorption by activated carbon (2001) Journal of Colloid and Interface Science, 240 (1), pp. 1-8Toles, C.A., Marshall, W.E., Johns, M.M., Surface functional groups on acid-activated nutshell carbons (1999) Carbon, 37 (8), pp. 1207-1214Mcdermott, C.M., Feola, R., Plude, J., Detection of cyanobacterial toxins (microcystins) in waters of northeastern Wisconsin by a new immunoassay technique (1995) Toxicon, 33 (11), pp. 1433-1442Ueno, Y., Nagata, S., Tsutsumi, T., Hasegawa, A., Yoshida, F., Suttajit, M., Mebs, D., Vasconcelos, V., Survey of microcystins in environmental water by a highly sensitive immunoassay based on monoclonal antibody (1996) Natural toxins, 4 (6), pp. 271-276Sivonen, K., Jones, G., Cyanobacterial toxins (1999) Toxic Cyanobacteria in Water, pp. 55-124. , A guide to their public health consequences, monitoring and management, and, ed, Routledge, UK: E&FN Spon;Robillot, C., Vinh, J., Puiseux-Dao, S., Hennion, M.C., Hepatotoxin Production Kinetics of the Cyanobacterium Microcystis aeruginosa PCC 7820, as Determined by HPLC-Mass Spectrometry and Protein Phosphatase Bioassay (2000) Environmental Science & Technology, 34 (16), pp. 3372-3378Pyo, D., Moon, D., Adsorption of microcystin LR by activated carbon fibers (2005) Bulletin of the Korean Chemical Society, 26 (12), pp. 2089-2092Yan, H., Gong, A., He, H., Zhou, J., Wei, Y., Lv, L., Adsorption of microcystins by carbon nanotubes (2006) Chemosphere, 62 (1), pp. 142-148Mohamed, Z.A., Carmichael, W.W., An, J., El-Sharouny, H.M., Activated carbon removal efficiency of microcystins in an aqueous cell extract of Microcystis aeruginosa and Oscillatoria tenuis strains isolated from Egyptian freshwaters (1999) Environmental toxicology, 14 (1), pp. 197-20

Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates

We calculate the energies of three-quark states with definite permutation symmetry (i.e. of SU(6) multiplets) in the N=0,1,2 shells, confined by the Y-string three-quark potential. The exact Y-string potential consists of one, so-called three-string term, and three angle-dependent two-string terms. Due to this technical complication we treat the problem at three increasingly accurate levels of approximation: 1) the (approximate) three-string potential expanded to first order in trigonometric functions of hyper-spherical angles; 2) the (approximate) three-string potential to all orders in the power expansion in hyper-spherical harmonics, but without taking into account the transition(s) to two-string potentials; 3) the exact minimal-length string potential to all orders in power expansion in hyper-spherical harmonics, and taking into account the transition(s) to two-string potentials. We show the general trend of improvement %convergence of these approximations: The exact non-perturbative corrections to the total energy are of the order of one per cent, as compared with approximation 2), yet the exact energy differences between the $[20,1^{+}], [70,2^{+}], [56,2^{+}], [70,0^{+}]$-plets are shifted to 2:2:0.9, from the Bowler and Tynemouth separation rule 2:2:1, which is obeyed by approximation 2) at the one per cent level. The precise value of the energy separation of the first radial excitation ("Roper") $[56^{\prime},0^{+}]$-plet from the $[70,1^{-}]$-plet depends on the approximation, but does not become negative, i.e. the "Roper" remains heavier than the odd-parity $[70,1^{-}]$-plet in all of our approximations.Comment: 19 pages, 6 figure