Assessing the benefits of international portfolio diversification in bonds and stocks.

This paper considers a stylized asset pricing model where the returns from exchange rates, stocks and bonds are linked by basic risk-arbitrage relationships. Employing GMM estimation and monthly data for 18 economies and the US (treated as the domestic country), we identify through a simple test the countries whose assets strongly comove with US assets and the countries whose assets might other larger diversification benefits. We also show that the strengthening of the comovement of returns across countries is neither a gradual process nor a global phenomenon, reinforcing the case for international diversification. However, our results suggest that fund managers are better other constructing portfolios selecting assets from a subset of countries than relying on either fully inter-nationally diversified or purely domestic portfolios. JEL Classification: F31, G10asset pricing, Exchange Rates, international parity conditions, market integration, stochastic discount factor

Bulls, Bears and Excess Volatility: can currency intervention help?

Asset mis-pricing may reflect investor psychology, with excess volatility arising from switches of sentiment. For a floating exchange rate where fundamentals follow a random walk, we show that excess volatility can be generated by the repeated entry and exit of currency 'bulls' and 'bears' with switches driven by 'draw-down' trading rules. We argue that non-sterilised intervention - in support of 'monitoring band' - can reduce excess volatility by coordinating beliefs in line with policy. Strategic complementarity in the foreign exchange market suggests that sterilised intervention may also play a coordinating role

Microstructure and mechanical behaviour of cemented soils lightened by foam

The management of large amounts of excavated soil is a primary problem in civil engineering. However, if the excavated soil can be reused as a material in the same construction project (or in a different one) for backfilling, trench reinstatement, soil embankments or substituting quarrying material in productive processes, it can be qualified as by-product with clear advantages in terms of environmental and economic costs. A suitable solution for reuse of excavated soil is the addition of cement and foam to produce lightweight cemented soils (LWCS). Lightweight cemented soil is prepared by mixing soil with water, cement and an air foam. The aim of this technique is to obtain a material with high workability in the fresh state (so that it can be transferred by pumping from batch plant to the construction site and poured) improved mechanical properties of the hardened paste given by the binding agent (as cement) and a specific low density (varying from 6 to 15 kN/m3) thanks to the addition of a foam. The fresh paste is self-levelling and no compaction is required, thus reducing construction time. In this experimental study, the influence of addition of cement and foam to soil on mineralogical and microstructural features is presented. Time dependent mineralogical and microstructural changes have been monitored at increasing curing time by means of X Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Mercury Intrusion Porosimetry (MIP). Mechanical behaviour of treated soil has been investigated by means of oedometric and direct shear tests. Chemo-physical evolution induced by cement addition is the major responsible for mechanical improvement shown by treated samples. Porosity of samples induced by foam addition plays a key role in the mechanical response of lightweight cemented samples, inducing a transition of stress-strain behaviour from brittle and dilative to ductile and contractile as foam content is increased. The Mohr Coulomb criterion was adopted to describe the failure surface of cemented and lightweight cemented soils. A unique failure surface which takes account of cement factor, curing time and amount of foam was determined

New-onset diabetes after kidney transplantation: Prevalence, risk factors, and management

New-Onset Diabetes After Transplantation (NODAT) is an increasingly recognized severe metabolic complication of kidney transplantation causing lower graft function and survival and reduced long-term patient survival mainly due to cardiovascular events. The real incidence of NODAT after kidney transplantation is difficult to establish, because different classification systems and definitions have been employed over the years. Several risk factors, already present before or arising after transplantation, in particular the employed immunosuppressive regimens, have been related to the development of NODAT. However the responsible pathogenic mechanisms are still far to be perfectly known. Awareness of NODAT and of the NODAT-related factors is of paramount importance for the clinicians in order to individuate higher risk patients and arrange screening strategies. The risk of NODAT can be reduced by planning preventive measures and by tailoring immunosuppressive regimens according to the patient characteristics. Once NODAT has been diagnosed, the administration of specific anti-hyperglycemic therapy is mandatory to reach a tight glycemic control, which contributes to significantly reduce posttransplant mortality and morbidity

Caldera unrest driven by CO2-induced drying of the deep hydrothermal system

Interpreting volcanic unrest is a highly challenging and non-unique problem at calderas, since large hydrothermal systems may either hide or amplify the dynamics of buried magma(s). Here we use the exceptional ground displacement and geochemical datasets from the actively degassing Campi Flegrei caldera (Southern Italy) to show that ambiguities disappear when the thermal evolution of the deep hydrothermal system is accurately tracked. By using temperatures from the CO2-CH4 exchange of 13C and thermodynamic analysis of gas ascending in the crust, we demonstrate that after the last 1982-84 crisis the deep hydrothermal system evolved through supercritical conditions under the continuous isenthalpic inflow of hot CO2-rich gases released from the deep (~8 km) magma reservoir of regional size. This resulted in the drying of the base of the hot hydrothermal system, no more buffered along the liquid-vapour equilibrium, and excludes any shallow arrival of new magma, whose abundant steam degassing due to decompression would have restored liquid-vapour equilibrium. The consequent CO2-infiltration and progressive heating of the surrounding deforming rock volume cause the build-up of pore pressure in aquifers, and generate the striking temporal symmetry that characterizes the ongoing uplift and the post-1984 subsidence, both originated by the same but reversed deformation mechanism

Entrapping Contrast Agent in Nanovescicles

Cancer and cardiovascular diseases are silent killers which cause million deaths worldwide every year and this number is expected to triple by 2035. Current diagnostic techniques cannot easily, safely, and effectively detect these human body lesions in the early stage, nor can they characterize the lesion features. In this context, the biological application of nanoparticles is a rapidly developing area of nanotechnology that raises new possibilities in the diagnosis and treatment of pathologies. Recently, rational design of a new class of contrast agents (CAs), based on biopolymers (hydrogels), have received considerable attention in Magnetic Resonance Imaging (MRI) diagnostic field. Several strategies have been adopted to improve relaxivity without chemical modification of the commercial CAs, however, understanding the MRI enhancement mechanism remains a challenge. Here, in order to develop a safe and more efficient MRI CA for imaging applications, the basic principles ruling biopolymer-CAs interactions are investigated to better understand their influence on the relaxometric properties of the CA by adopting a multidisciplinary experimental approach. In addition, the effect of the hydration of the hydrogel structure on the relaxometric properties, called Hydrodenticity, is used to develop Gadolinium-based polymer nanovectors with improved MRI relaxation time. The experimental results indicate that the   entrapment of metal chelates in hydrogel nanostructures offers a versatile platform for developing different high performing CAs for diseases diagnosis

Shade Effects on Athletic Field Playing Characteristics of Overseeded and Non-Overseeded Bermudagrass

In many athletic stadiums around the world, reduced light levels from the stadium structure can significantly reduce turfgrass quality and playing characteristics. In most warm-weather stadiums, the primary surface is bermudagrass which is commonly overseeded with perennial ryegrass to provide a winter and spring playing surface. The objective of this study was to examine the effects of four shade levels on turfgrass quality and playing characteristics of overseeded and non-overseeded bermudagrass (cv. Riviera). Shade levels included a non-shaded control and shade treatments which blocked 30%, 60%, and 90% of ambient light. These shade levels resulted in average daily PAR loads of 45.1, 29.6, 16.7, and 4.7 mol PAR / m2 / day, respectively. Data collection included both quality and playability characteristics. The effects of shading became obvious as the study continued into early summer, with the 90% shade plots losing almost all cover and the 60% shade plots losing up to 40% of coverage through mid-summer. The 30% shade plots had a slight decline in turfgrass coverage, although, still retained close to 90% coverage. Based on these results, a minimum daily light load of approximately 30 mol PAR / m2 / day is needed to sustain Riviera bermudagrass at or near 100% coverage. In the overseeded plots, the only shade treatment that caused a significant reduction in turfgrass coverage was the 90% shade treatment (4.7 mol PAR / m2 / day). There was a significant decrease in the amount of bermudagrass present in the overseeded plots in mid-summer, suggesting that increased shading was causing a shift in population from the warm-season bermudagrass to the cool-season perennial ryegrass. In both overseeded and non-overseeded plots, rotational resistance (traction) decreased even with modest levels of shade , which is likely correlated to a decrease in turfgrass densit

Resolving cryptic species complexes in marine protists: phylogenetic haplotype networks meet global DNA metabarcoding datasets

Marine protists have traditionally been assumed to be lowly diverse and cosmopolitan. Yet, several recent studies have shown that many protist species actually consist of cryptic complexes of species whose members are often restricted to particular biogeographic regions. Nonetheless, detection of cryptic species is usually hampered by sampling coverage and application of methods (e.g. phylogenetic trees) that are not well suited to identify relatively recent divergence and ongoing gene flow. In this paper, we show how these issues can be overcome by inferring phylogenetic haplotype networks from global metabarcoding datasets. We use the Chaetoceros curvisetus (Bacillariophyta) species complex as study case. Using two complementary metabarcoding datasets (Ocean Sampling Day and Tara Oceans), we equally resolve the cryptic complex in terms of number of inferred species. We detect new hypothetical species in both datasets. Gene flow between most of species is absent, but no barcoding gap exists. Some species have restricted distribution patterns whereas others are widely distributed. Closely related taxa occupy contrasting biogeographic regions, suggesting that geographic and ecological differentiation drive speciation. In conclusion, we show the potential of the analysis of metabarcoding data with evolutionary approaches for systematic and phylogeographic studies of marine protists

Spring-time dynamics of diatom communities in landfast and underlying platelet ice in Terra Nova Bay, Ross Sea, Antarctica

We investigated the composition of diatom communities in annual fast ice and their variations over time during the 1999 austral spring in Terra Nova Bay (Ross Sea, Antarctica). Diatoms varied along the ice core in both cell abundance and species composition, with a minimum in the lower layer and a peak in the platelet ice. Planktonic species constituted in total about 98% of the diatom assemblage in the surface layers of the ice core down to the thickness of 220 cm. In the bottom ice and the underlying platelet-ice layer, the contribution of planktonic diatoms was lower (60% and 65%, respectively) at the beginning of the sampling period, and then decreased further to reach 30% in the bottom ice, where a remarkable biomass increase over time was caused by in situ growth and accumulation of benthic species. By contrast in the platelet-ice layer only small changes were recorded in the composition of the diatom assemblage, which was mainly constituted by the bloom of Fragilariopsis nana. The benthic species are generally not found in the water column, while species in the platelet-ice layer presumably constitute the seed for the initial plankton bloom during the ice-free periods in Terra Nova Bay