International order flows: Explaining equity and exchange rate returns

Macroeconomic models of equity and exchange rate returns perform poorly at high frequencies. The proportion of daily returns that these models explain is essentially zero. Instead of relying on macroeconomic determinants, we model equity price and exchange rate behavior based on a concept from microstructure – order flow. The international order flows are derived from belief changes of different investor groups in a two-country setting. We obtain a structural relationship between equity returns, exchange rate returns and their relationship to home and foreign equity market order flow. To test the model we construct daily aggregate order flow data from 800 million equity trades in the U.S. and France from 1999 to 2003. Almost 60% of the daily returns in the S&P100 index are explained jointly by exchange rate returns and aggregate order flows in both markets. As predicted by the model, daily exchange rate returns and order flow into the French market have significant incremental explanatory power for the daily S&P returns. The model implications are also validated for intraday returns.

Coordination environment of [UO2Br4](2-) in ionic liquids and crystal structure of [Bmim](2)[UO2Br4]

The complex formed by the reaction of the uranyl ion, UO22+, with bromide ions in the ionic liquids 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmiml[Tf2N]) and methyl-tributylammonium bis(trifluoromethylsulfonyl)imide ([MeBu3N][Tf2N]) has been investigated by UV-Vis and U L-III-edge EXAFS spectroscopy and compared to the crystal structure of [Bmim](2)[UO2Br4]. The solid state reveals a classical tetragonal bipyramid geometry for [UO2Br4](2-) with hydrogen bonds between the Bmim(+) and the coordinated bromides. The UV-Vis spectroscopy reveals the quantitative formation of [UO2Br4](2-) when a stoichiometric amount of bromide ions is added to UO2(CF3SO3)(2) in both Tf2N-based ionic liquids. The absorption spectrum also suggests a D-4h symmetry for [UO2Br4](2-) in ionic liquids, as previously observed for the [UO2Cl4](2-) congener. EXAFS analysis supports this conclusion and demonstrates that the [UO2Br4](2-) coordination polyhedron is maintained in the ionic liquids without any coordinating solvent or water molecules. The mean U-O and U-Br distances in the solutions, determined by EXAFS, are, respectively, 1.766(2) and 2.821(2)angstrom in [Bmim][Tf2N], and, respectively, 1.768(2) and 2.827(2) angstrom, in [MeBu3N][Tf2N]. Similar results are obtained in both ionic liquids indicating no significant influence of the ionic liquid cation either on the complexation reaction or on the structure of the uranyl species. (C) 2009 Elsevier Ltd. All rights reserved.

Understanding Corporate Governance Reform in South Africa: Anglo-American Divergence, the King Reports and Hybridization

This article investigates corporate governance reform in South Africa in the context of the country’s international links with Anglo-American corporate governance and domestic pursuit of socioeconomic development. Two key questions are evaluated. (a) How has divergence within the Anglo-American model influenced corporate governance reform in South Africa? (b) Can South Africa’s historical closeness to the Anglo-American model be combined with increasing attention to stakeholder issues to produce a hybrid “African model” of corporate governance? Evaluating these questions, the following issues are explored in turn: the contrast between shareholder and stakeholder models, divergence between U.S. and U.K. approaches to corporate governance as exemplified by Sarbanes-Oxley, locating a South African approach in context of the Anglo-American model, the King reports and an emerging “African” model of corporate governance, and the role of international and domestic factors in shaping South Africa’s ongoing reform process.

Modeling Multivariate Interest Rates Using Time-Varying Copulas and Reducible Nonlinear Stochastic Differential Equations

We propose a new approach for modeling nonlinear multivariate interest rate processes based on time-varying copulas and reducible stochastic differential equations (SDEs). In the modeling of the marginal processes, we consider a class of nonlinear SDEs that are reducible to Ornstein--Uhlenbeck (OU) process or Cox, Ingersoll, and Ross (1985) (CIR) process. The reducibility is achieved via a nonlinear transformation function. The main advantage of this approach is that these SDEs can account for nonlinear features, observed in short-term interest rate series, while at the same time leading to exact discretization and closed-form likelihood functions. Although a rich set of specifications may be entertained, our exposition focuses on a couple of nonlinear constant elasticity volatility (CEV) processes, denoted as OU-CEV and CIR-CEV, respectively. These two processes encompass a number of existing models that have closed-form likelihood functions. The transition density, the conditional distribution function, and the steady-state density function are derived in closed form as well as the conditional and unconditional moments for both processes. In order to obtain a more flexible functional form over time, we allow the transformation function to be time varying. Results from our study of U.S. and UK short-term interest rates suggest that the new models outperform existing parametric models with closed-form likelihood functions. We also find the time-varying effects in the transformation functions statistically significant. To examine the joint behavior of interest rate series, we propose flexible nonlinear multivariate models by joining univariate nonlinear processes via appropriate copulas. We study the conditional dependence structure of the two rates using Patton (2006a) time-varying symmetrized Joe--Clayton copula. We find evidence of asymmetric dependence between the two rates, and that the level of dependence is positively related to the level of the two rates. (JEL: C13, C32, G12) Copyright The Author 2010. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org, Oxford University Press.

Bioaccessibility of trace elements in soils in Northern Ireland

Assessment of elevated concentrations of potentially toxic elements (PTE) in soils and the association with specific soil parent material have been the focus of research for a number of years. Risk-based assessment of potential exposure scenarios to identified elevated PTE concentrations has led to the derivation of site- and contaminant-specific soil guideline values (SGVs), which represent generic assessment criteria (GACs) to identify exceeded levels that may reflect an unacceptable risk to human health. A better understanding of the ‘bioavailable’ or ‘bioaccessible’ contaminant concentrations offers an opportunity to better refine contaminant exposure assessments. Utilizing a comprehensive soil geochemical dataset for Northern Ireland provided by the Tellus Survey (GSNI) in conjunction with supplementary bioaccessibility testing of selected soil samples following the Unified BARGE Method, this paper uses exploratory data analysis and geostatistical analysis to investigate the spatial variability of pseudo-total and bioaccessible concentrations of As, Cd, Co, Cr. Cu, Ni, Pb, U, V and Zn. The paper investigates variations in individual element concentrations as well as cross-element correlations and observed lithological/pedological associations. The analysis of PTE concentrations highlighted exceeded levels of GAC values for V and Cr and exceeded SGV/GAC values for Cd, Cu, Ni, Pb, and Zn. UBM testing showed that for some soil parent materials associated with elevated PTE concentrations e.g. the Antrim Lava Group with high Ni concentrations, the measured oral bioaccessible fraction was relatively low. For other soil parent materials with relatively moderate PTE concentrations, measured oral bioaccessible fraction was relatively high (e.g. the Gala Sandstone Group of the Southern Uplands-Down Longford Terrain). These findings have implications for regional human health risk assessments for specific PTEs.

Risk assessment of potentially toxic elements in agricultural soils and maize tissues from selected districts in Tanzania

A field survey was conducted to investigate the contamination of potentially toxic elements (PTEs) arsenic (As), lead (Pb), chromium (Cr), and nickel (Ni) in Tanzanian agricultural soils and to evaluate their uptake and translocation in maize as proxy to the safety of maize used for human and animal consumption. Soils and maize tissues were sampled from 40 farms in Tanzania and analyzed using inductively coupled plasma-mass spectrometry in the United Kingdom. The results showed high levels of PTEs in both soils and maize tissues above the recommended limits. Nickel levels of up to 34.4 and 56.9mgkg(-1) respectively were found in some maize shoots and grains from several districts. Also, high Pb levels >0.2mgkg(-1) were found in some grains. The grains and shoots with high levels of Ni and Pb are unfit for human and animal consumption. Concentrations of individual elements in maize tissues and soils did not correlate and showed differences in uptake and translocation. However, Ni showed a more efficient transfer from soils to shoots than As, Pb and Cr. Transfer of Cr and Ni from shoots to grains was higher than other elements, implying that whatever amount is assimilated in maize shoots is efficiently mobilized and transferred to grains. Thus, the study recommended to the public to stop consuming and feeding their animals maize with high levels of PTEs for their safety.

Lead isotopes and lead shot ingestion in the globally threatened marbled teal (Marmaronetta angustirostris) and white-headed duck (Oxyura leucocephala)

Lead isotope ratios ((206)Pb/(207)Pb and (208)Pb/(207)Pb) and concentrations in the livers and bones of marbled teal and white-headed duck found dead or moribund were determined in order to establish the main lead source in these waterfowl species. Lead concentrations in bone (dry weight) and liver (wet weight) were found to be very high in many of the white-headed ducks (bone: geometric mean=88.9 ppm, maximum=419 ppm; liver: geometric mean=16.8 ppm, maximum=57.0 ppm). Some of the marbled teal had high lead levels in the bones but liver lead levels were all low (bone: geometric mean=6.13 ppm, maximum=112 ppm; liver: geometric mean=0.581 ppm, maximum=4.77 ppm). Ingested lead shot were found in 71% of the white-headed duck and 20% of the marbled teal. The (206)Pb/(207)Pb ratio in livers and bones of white-headed ducks and marbled teals showed no significant differences compared to the ratios obtained from lead shot. The (206)Pb/(207)Pb ratio in bones of marbled teal ducklings with the highest lead concentrations tended to resemble the ratios of lead shot, which supports our hypothesis that the lead was derived from the hens. We also found that the lead ratios of lead shot and lead ratios described for soils in the area overlapped, but also that the isotopic ratio (206)Pb/(207)Pb in lead shot used in Spain has a narrow range compared with those used in North America. The principal source of lead in many of these birds was, however, most likely lead shot, as supported by the similar isotopic ratios, high lead concentrations in tissues and evidence of ingested shot.

Altered porphyrin excretion and histopathology of greylag geese (Anser anser) exposed to soil contaminated with lead and arsenic in the Guadalquivir Marshes, southwestern Spain

Greylag geese (Anser anser) in the Guadalquivir Marshes (southwestern Spain) can be exposed to sources of inorganic pollution such as heavy metals and arsenic from mining activities or Pb shot used for hunting. We have sampled 270 fecal excreta in different areas of the marshes in 2001 to 2002 to evaluate the exposure to Pb, Zn, Cu, Mn, and As and to determine its relationship with soil ingestion and with the excretion of porphyrins and biliverdin as biomarkers. These effects and the histopathology of liver, kidney, and pancreas were also studied in 50 geese shot in 2002 to 2004. None of the geese had ingested Pb shot in the gizzard. This contrasts with earlier samplings before the ban of Pb shot for waterfowl hunting in 2001 and the removal of Pb shot in points of the Doñana National Park (Spain) in 1999 to 2000. The highest exposure through direct soil ingestion to Pb and other studied elements was observed in samples from Entremuros, the area of the Doñana Natural Park affected by the Aznalcóllar mine spill in 1998. Birds from Entremuros also more frequently showed mononuclear infiltrates in liver and kidney than birds from the unaffected areas, although other more specific lesions of Pb or Zn poisoning were not observed. The excretion of coproporphyrins, especially of the isomer I, was positively related to the fecal As concentration, and the ratio of coproporphyrin III/I was positively related to fecal Pb concentration. Biliary protoporphyrin IX concentration was also slightly related to hepatic Pb concentration. This study reflects biological effects on terrestrial animals by the mining pollution in Doñana that can be monitored with the simple noninvasive sampling of feces.

After the Aznalcóllar mine spill:arsenic, zinc, selenium, lead and copper levels in the livers and bones of five waterfowl species

In April 1998, a holding lagoon containing pyrite ore processing waste, failed and released 5-6 million m3 of highly polluting sludge and acidic water. Over 2650 ha of the internationally important Doñana Natural Park became contaminated, along with <100 ha of the more pristine Doñana National Park. In order to assess the affect of the spill on waterfowl from Doñana, bone and liver samples from 124 individuals have been analysed for As, Pb, Cu, Zn and Se. Five species have been studied, from the Rallidae (rails), Anatini (dabbling ducks) and Aythyini (pochards) families. Geometric mean bone concentrations 2-3 months after the spill were in the order of Zn > Cu > Pb > Se > As, while liver concentrations were in the order of Zn > Cu > Se > Pb > As. Dry weight bone concentrations ranged from n.d-1.76 mg kg(-1) As, 109.4-247.6 mg kg(-1) Zn, 0.06-1.27 mg kg(-1) Se, n.d-134.11 mg kg(-1) Pb, and 2.18-8.92 mg kg(-1) Cu. Wet weight liver concentrations ranged from n.d-0.34 mg kg(-1) As, 29.8-220.1 mg kg(-1) Zn, 0.15-0.85 mg kg(-1) Se, n.d-3.80 mg kg(-1) Pb, and 7.30-742.96 mg kg(-1) Cu. The most important factor related to the accumulation of these metals was commonly species; however, location and sex also had important effects on liver As levels, location and age affected Cu levels, while Zn and Pb were affected by age, sex and location. Birds from Natural Park areas were found to have significantly higher levels of bone Zn, Pb and Cu, and liver As and Cu than birds from National Park areas. Female birds had higher liver As, Zn and Pb than males; whilst adults appeared to have lower bone As and Zn but higher liver Pb than chicks/juveniles. Although metal concentrations were elevated in certain individuals, in the majority of birds studied, they did not reach levels widely considered to be toxic. However, it would appear that As and Cu liver levels (which may be indicative of short-medium term pollutant exposure) were elevated in waterbirds which died in the spill contaminated Natural Park, 2-3 months after the disaster.

Lead and arsenic in bones of birds of prey from Spain

The bones (humerus and/or femur) of 229 birds of prey from 11 species were analyzed for Pb and As to evaluate their exposure to Pb shot. The species with the highest mean Pb levels were red kite (Milvus milvus) and Eurasian griffon (Gyps fulvus), and the species with the lowest levels were Eurasian buzzard (Buteo buteo) and booted eagle (Hieraaetus pennatus). Red kite also had the highest mean As level, an element present in small amounts in Pb shot. Elevated bone Pb concentrations (>10 microg/g dry weight) were found in 10 birds from six species. Clinical signs compatible with lethal Pb poisoning and/or excessive bone Pb concentrations (>20 microg/g) were observed in one Eurasian eagle-owl (Bubo bubo), one red kite, and one Eurasian griffon. Pb poisoning has been diagnosed in eight upland raptor species in Spain to date.

High-resolution reconstruction of atmospheric deposition of trace metals and metalloids since AD 1400 recorded by ombrotrophic peat cores in Hautes-Fagnes, Belgium

The objective of our study was to determine the trace metal accumulation rates in the Misten bog, Hautes-Fagnes, Belgium, and assess these in relation to established histories of atmospheric emissions from anthropogenic sources. To address these aims we analyzed trace metals and metalloids (Pb, Cu, Ni, As, Sb, Cr, Co, V, Cd and Zn), as well as Pb isotopes, using XRF, Q-ICP-MS and MC-ICP-MS, respectively in two 40-cm peat sections, spanning the last 600 yr. The temporal increase of metal fluxes from the inception of the Industrial Revolution to the present varies by a factor of 5–50, with peak values found between AD 1930 and 1990. A cluster analysis combined with Pb isotopic composition allows the identification of the main sources of Pb and by inference of the other metals, which indicates that coal consumption and metallurgical activities were the predominant sources of pollution during the last 600 years.

Spatial patterns and autocorrelation in the response of microarthropods to soil pollutants: The example of oribatid mites in an abandoned mining and smelting area

Although exogenous factors such as pollutants can act on endogenous drivers (e.g. dispersion) of populations and create spatially autocorrelated distributions, most statistical techniques assume independence of error terms. As there are no studies on metal soil pollutants and microarthropods that explicitly analyse this key issue, we completed a field study of the correlation between Oribatida and metal concentrations in litter, organic matter and soil in an attempt to account for spatial patterns of both metals and mites. The 50-m wide study area had homogenous macroscopic features, steep Pb and Cu gradients and high levels of Zn and Cd. Spatial models failed to detect metal-oribatid relationships because the observed latitudinal and longitudinal gradients in oribatid assemblages were independent of the collinear gradients in the concentration of metals. It is therefore hypothesised that other spatially variable factors (e.g. fungi, reduced macrofauna) affect oribatid assemblages, which may be influenced by metals only indirectly. (C) 2009 Elsevier Ltd. All rights reserved.

Low-energy cranberry juice decreases lipid oxidation and increases plasma antioxidant capacity in women with metabolic syndrome

Cranberries, high in polyphenols, have been associated with several cardiovascular health benefits, although limited clinical trials have been reported to validate these findings. We tested the hypothesis that commercially available low-energy cranberry juice (Ocean Spray Cranberries, Inc, Lakeville-Middleboro, Mass) will decrease surrogate risk factors of cardiovascular disease, such as lipid oxidation, inflammation, and dyslipidemia, in subjects with metabolic syndrome. In a randomized, double-blind, placebo-controlled trial, participants identified with metabolic syndrome (n = 15-16/group) were assigned to 1 of 2 groups: cranberry juice (480 mL/day) or placebo (480 mL/day) for 8 weeks. Anthropometrics, blood pressure measurements, dietary analyses, and fasting blood draws were conducted at screen and 8 weeks of the study. Cranberry juice significantly increased plasma antioxidant capacity (1.5 ± 0.6 to 2.2 ± 0.4 µmol/L [means ± SD], P <.05) and decreased oxidized low-density lipoprotein and malondialdehyde (120.4 ± 31.0 to 80.4 ± 34.6 U/L and 3.4 ± 1.1 to 1.7 ± 0.7 µmol/L, respectively [means ± SD], P <.05) at 8 weeks vs placebo. However, cranberry juice consumption caused no significant improvements in blood pressure, glucose and lipid profiles, C-reactive protein, and interleukin-6. No changes in these parameters were noted in the placebo group. In conclusion, low-energy cranberry juice (2 cups/day) significantly reduces lipid oxidation and increases plasma antioxidant capacity in women with metabolic syndrome.

Tailoring Alphabetical Metamaterials in Optical Frequency: Plasmonic Coupling, Dispersion, and Sensing

Tailoring optical properties of artificial metamaterials, whose optical properties go beyond the limitations of conventional and naturally occurring materials, is of importance in fundamental research and has led to many important applications such as security imaging, invisible cloak, negative refraction, ultrasensitive sensing, transformable and switchable optics. Herein, by precisely controlling the size, symmetry and topology of alphabetical metamaterials with U, S, Y, H, U-bar and V shapes, we have obtained highly tunable optical response covering visible-to-infrared (Vis-NIR) optical frequency. In addition, we show a detailed study on the physical origin of resonance modes, plasmonic coupling, the dispersion of electronic and magnetic surface plasmon polaritons, and the possibility of negative refraction. We have found that all the electronic and magnetic modes follow the dispersion of surface plasmon polaritons thus essentially they are electronic- and magnetic-surface-plasmon-polaritons-like (ESPP-like and MSPP-like) modes resulted from diffraction coupling between localized surface plasmon and freely-propagating light. Based on the fill factor and formula of magnetism permeability, we predict that the alphabetical metamaterials should show the negative refraction capability in visible optical frequency. Furthermore, we have demonstrated the specific ultrasensitive surface enhanced Raman spectroscopy (SERS) sensing of monolayer molecules and femtomolar food contaminants by tuning their resonance to match the laser wavelength, or by tuning the laser wavelength to match the plasmon resonance of metamaterials. Our tunable alphabetical metamaterials provide a generic platform to study the electromagnetic properties of metamaterials and explore the novel applications in optical frequency.

Magma Evolution in the Primitive, Intra-oceanic Tonga Arc: Rapid Petrogenesis of Dacites at Fonualei Volcano

Fonualei is unusual amongst subaerial volcanoes in the Tonga arc because it has erupted dacitic vesicular lavas, tuffs and phreomagmatic deposits for the last 165 years. The total volume of dacite may approach 5 km(3) and overlies basal basaltic andesite and andesite lavas that are constrained to be less than a few millennia in age. All of the products are crystal-poor and formed from relatively low-viscosity magmas inferred to have had temperatures of 1100-1000 degrees C, 2-4 wt % H2O and oxygen fugacities 1-2 log units above the quartz-fayalite-magnetite buffer. Major and trace element data, along with Sr-Nd-Pb and U-Th-Ra isotope data, are used to assess competing models for the origin of the dacites. Positive correlations between Sc and Zr and Sr rule out evolution of the within-dacite compositional array by closed-system crystal fractionation of a single magma batch. An origin by partial melting of lower crustal amphibolites cannot reproduce these data trends or, arguably, any of the dacites either. Instead, we develop a model in which the dacites reflect mixing between two dacitic magmas, each the product of fractional crystallization of basaltic andesite magmas formed by different degrees of partial melting. Mixing was efficient because the two magmas had similar temperatures and viscosities. This is inferred to have occurred at shallow (2-6 km) depths beneath the volcano. U-Th-Ra disequilibria in the basaltic andesite and andesite indicate that the parental magmas had fluids added to their mantle source regions less than 8 kyr ago and that fractionation to the dacitic compositions took less than a few millennia. The 165 year eruption period for the dacites implies that mixing occurred on a similar timescale, possibly during ascent in conduits. The composition of the dacites renders them unsuitable candidates as contributors to average continental crust.