42 research outputs found
Risk Diversification by European Financial Conglomerates
We study the dependence between the downside risk of European banks and insurers. Since the downside risk of banks and insurers differs, an interesting question from a supervisory point of view is the risk reduction that derives from diversification within large banks and financial conglomerates. We discuss the limited value of the normal distribution based correlation concept, and propose an alternative measure which better captures the downside dependence given the fat tail property of the risk distribution. This measure is estimated and indicates better diversification benefits for conglomerates versus large banks
X-ray reflectivity of an Sb delta-doping layer in silicon
X‐ray reflectivity measurements were made on Si(001) crystals containing a delta‐doping layer of Sb atoms a few nanometers below the surface. The measurements show the Sb doping profile to be abrupt towards the substrate side of the sample and to decay towards the surface with a characteristic decay length of 1.01 nm
Systemic Risk & Diversification across European Banks and Insurers
The mutual and cross company exposures to fat-tail distributed risks determine the potential impact of a financial crisis on banks and insurers. We examine the systemic interdependencies within and across the European banking and insurance sectors during times of stress by means of extreme value analysis. While insurers exhibit a slightly higher interdependency in comparison with banks, the interdependency across the two sectors turns out to be considerably lower. This suggests that downside risk can be lowered through financial conglomeration. © 2012 Elsevier B.V
Assessment of the environmental status of the coastal and marine aquatic environment
Policymakers and managers have a very different philosophy and approach to achieving healthy coastal and marine ecosystems than scientists. In this paper we discuss the evolution of the assessment of the chemical status in the aquatic environment and the growing rift between the political intention (precautionary principle) and scientific developments (adaptive and evidence-based management) in the context of the pitfalls and practicalities confronting the current Marine Strategy Framework Directive (MSFD). The conclusion is that policymakers and water managers should move with the times and take on board new techniques that scientists are using to assess chemical status and apply new scientific developments in assessment studies of the chemical status. These new techniques, such as bioassays, are cheaper than the classic approach of checking whether concentrations of certain individual priority compounds comply with permissible thresholds. Additionally, they give more insight into the real impacts of chemical compound
Bouwen met Noordzee-natuur : uitwerking Gebiedsagenda Noordzee 2050
In dit rapport wordt het concept ‘Bouwen met Noordzee-natuur’ uitgewerkt tot een aantal adviezen aan het Ministerie van Economische Zaken (EZ) om ‘Bouwen met Noordzee-natuur’ een stap verder te brengen in de concretisering. De definitie van ‘Bouwen met Noordzee-natuur’ zoals gebruikt in dit rapport is: Het gebruik maken van de zee en de natuur op een manier die leidt tot versterking van het mariene systeem, de natuur en de biodiversiteit (bron: Gebiedsagenda Noordzee 2050). Dat laatste kan vervolgens worden geoperationaliseerd als versterking van behoud en duurzaam gebruik van soorten en habitats die van nature in de Nederlandse Noordzee voorkomen, dan wel meer specifiek in relatie tot inheemse soorten en habitats van Natura 2000- en KRM-soorten en -gebieden, en/of inheemse rode lijst-soorten, en inheemse soorten en habitats van de OSPAR-lijst. De kans op introductie van exoten moet daarbij geminimaliseerd worden. In het voorliggend document zijn kansen en knelpunten voor het concept Bouwen met Noordzee-natuur geïnventariseerd door middel van een kennisinventarisatie, interviews en een workshop met stakeholders
Aerial sowing stopped the loss of alpine ash (Eucalyptus delegatensis) forests burnt by three short-interval fires in the Alpine National Park, Victoria, Australia
Polycyclic aromatic hydrocarbon-polluted dredged peat sediments and earthworms: a mutual interference
In lowland areas of the Netherlands, any peat sediments will gradually become enriched with anthropogenically derived Polycyclic Aromatic Hydrocarbons. Due to Dutch policy standards these (anaerobic) sediments are not allowed to be dredged and placed onto land. Under aerobic conditions, however, biodegradation of PAH is greatly enhanced. This degradation is further stimulated by colonisation of the sediments by earthworms. Laboratory experiments show that although earthworms do not avoid PAH-contaminated sediment, their burrowing-activity is reduced. Furthermore, these sediments have no significant ecotoxicological impacts on earthworms. Experimental introduction of earthworms into PAH-contaminated OECD-soil will result in a decrease in overall PAH content. In field surveys no significant differences in earthworm numbers between locations with fresh and old sediment could be found. It is concluded that dredging of PAH-contaminated sediment poses a very limited environmental threat, and that puttingthese sediments on land will improve PAH-biodegradation, partly through the colonisation by and activities of earthworms
Variation in the decomposition of Phragmites australis litter in a monomictic lake: the role of gammarids
A decomposition study has been carried out in Lake Geestmerambacht, a moderately deep (max. ca. 22 m), monomictic slightly brackish lake in The Netherlands. To assess the relative importance of biotic (benthos) and physico-chemical factors, the mass loss rate (K) of reed leaf litter was measured at 10 sites, both in winter and in summer, in the absence ('protected' litter bags) and the presence ('unprotected' litter bags) of invertebrates. The aim was to investigate the variation in mass loss rate within the habitat and between seasons, and the role of the litter-associated invertebrate community. The experiments showed high spatial variation in decomposition rates. The spatial pattern changed with season. In summer, decomposition rates were higher than in winter: 4.4 times in the presence of invertebrates, and 2.6 times in their absence. The exclusion of invertebrates ('protected' litter bags versus 'unprotected' litter bags) led to significantly lower decomposition rates. In particular, the decomposition rate was strongly correlated with the number of gammarids, the dominant taxon in the litter bags, which are well known for their ability to feed on leaf litter. The abundance of gammarids was directly correlated to the level of dissolved oxygen and inversely correlated to the effective fetch in summer, when the spatial structure of the decomposition process was evident. Therefore, the results of this study indicate that there are seasonal and spatial differences in the rate of detritus decomposition, most likely due to changes in habitat characteristics that influence the distribution of gammarids, key-species responsible for the first steps of the leaf breakdown in Lake Geestmerambacht. The spatial dependency of the process leads to formation of heterogeneous ecological patches in which the probability of disturbance propagation may vary
