An attempt to refine rockfall hazard zoning based on the kinetic energy, frequency and fragmentation degree

Rockfall hazard zoning is usually achieved using a qualitative estimate of hazard, and not an absolute scale. In Switzerland, danger maps, which correspond to a hazard zoning depending on the intensity of the considered phenomenon (e.g. kinetic energy for rockfalls), are replacing hazard maps. Basically, the danger grows with the mean frequency and with the intensity of the rockfall. This principle based on intensity thresholds may also be applied to other intensity threshold values than those used in Switzerland for rockfall hazard zoning method, i.e. danger mapping. In this paper, we explore the effect of slope geometry and rockfall frequency on the rockfall hazard zoning. First, the transition from 2D zoning to 3D zoning based on rockfall trajectory simulation is examined; then, its dependency on slope geometry is emphasized. The spatial extent of hazard zones is examined, showing that limits may vary widely depending on the rockfall frequency. This approach is especially dedicated to highly populated regions, because the hazard zoning has to be very fine in order to delineate the greatest possible territory containing acceptable risks.

A note on the convergence to competitive equilibria in economies with moral hazard

We examine the conditions under which competitive equilibria can beobtained as the limit, when the number of strategic traders getslarge, of Nash equilibria in economies with asymmetric informationon agents' effort and possibly imperfect observability of agents'trades. Convergence always occur when either effort is publiclyobserved (no matter what is the information available tointermediaries on agents' trades); or effort is private informationbut agents' trades are perfectly observed; or no information at allis available on agents' trades. On the other hand, when eachintermediary can observe its trades with an agent, but not theagent's trades with other intermediaries, the (Nash) equilibriawith strategic intermediaries do not converge to any of thecompetitive equilibria, for an open set of economies. The source ofthe difficulties for convergence is the combination of asymmetricinformation and the restrictions on the observability of tradeswhich prevent the formation of exclusive contractual relationshipsand generate barriers to entry in the markets for contracts.

Moral hazard and non-exclusive contracts

This paper studies equilibria for economies characterized by moral hazard(hidden action), in which the set of contracts marketed in equilibrium isdetermined by the interaction of financial intermediaries.The crucial aspect of the environment that we study is thatintermediaries are restricted to trade non-exclusive contracts: theagents' contractual relationships with competing intermediaries cannot bemonitored (or are not contractible upon). We fully characterize equilibrium allocations and contracts. In thisset-up equilibrium allocations are clearly incentive constrainedinefficient. A robust property of equilibria with non-exclusivity isthat the contracts issued in equilibrium do not implement the optimalaction. Moreover we prove that, whenever equilibrium contracts doimplement the optimal action, intermediaries make positive profits andequilibrium allocations are third best inefficient (where the definitionof third best efficiency accounts for constraints which capture thenon-exclusivity of contracts).

Moral hazard and dynamics of insider ownership stakes

In this paper, I analyze the ownership dynamics of N strategic risk-averse corporate insiders facing a moral hazard problem. A solution for the equilibrium share price and the dynamics of the aggregate insider stake is obtained in two cases: when agents can crediblycommit to an optimal ownership policy and when they cannot commit (time-consistent case). Inthe latter case, the aggregate stake gradually adjusts towards the competitive allocation. The speed of adjustment increases with N when outside investors are risk-averse, and does not depend on it when investors are risk-neutral. Predictions of the model are consistent with recent empirical findings.

Workgroup report: incorporating in vitro alternative methods for developmental neurotoxicity into international hazard and risk assessment strategies.

This is the report of the first workshop on Incorporating In Vitro Alternative Methods for Developmental Neurotoxicity (DNT) Testing into International Hazard and Risk Assessment Strategies, held in Ispra, Italy, on 19-21 April 2005. The workshop was hosted by the European Centre for the Validation of Alternative Methods (ECVAM) and jointly organized by ECVAM, the European Chemical Industry Council, and the Johns Hopkins University Center for Alternatives to Animal Testing. The primary aim of the workshop was to identify and catalog potential methods that could be used to assess how data from in vitro alternative methods could help to predict and identify DNT hazards. Working groups focused on two different aspects: a) details on the science available in the field of DNT, including discussions on the models available to capture the critical DNT mechanisms and processes, and b) policy and strategy aspects to assess the integration of alternative methods in a regulatory framework. This report summarizes these discussions and details the recommendations and priorities for future work.

Flood Plain Management & Hazard Mitigation Task Force Report, August 2008

The Flood Plain Management and Hazard Mitigation Task Force emphasizes the long-term benefits of mitigation and management to the entire state in preventing or reducing damages from floods and other hazards faced in Iowa. Investments in efforts to manage watershed areas and to mitigate any damages from floods or other disaster events benefit individuals, families, communities, agriculture, business and industry, and certainly public entities and infrastructure. The Task Force encourages the Rebuild Iowa Advisory Commission to balance the immediate needs for rebuilding to include the beginning of the investments required to effectively mitigate future damage and maintain effective policy in Iowa’s watersheds. The significance of the damage seen in Iowa from the tornadoes, storms, and floods of 2008 include the loss of eighteen Iowans in disaster-related events. This alone should inspire investment in mitigation efforts for all hazards. Much of the damage resulting from the disasters can be tied to floodplain management and hazard mitigation, pointing the way toward enhanced efforts and new initiatives to safeguard lives, property, and communities’ economic health. Even so, it must be recognized that the weather events throughout last winter and spring added impetus to the rains and storms that ultimately resulted in record flooding. Some perspective must be maintained as planning progresses and significant investments in mitigation are considered to meet a specific level of safety and protection from future threats. The Task Force identified a number of issues, and four were agreed-upon as those with the highest priority to be addressed by the Task Force through a set of recommendations.

Supplemental Information to the August 2008 Flood Plain Management & Hazard Mitigation Task Force Report, August 2008

The Flood Plain Management and Hazard Mitigation Task Force emphasizes the long-term benefits of mitigation and management to the entire state in preventing or reducing damages from floods and other hazards faced in Iowa. Investments in efforts to manage watershed areas and to mitigate any damages from floods or other disaster events benefit individuals, families, communities, agriculture, business and industry, and certainly public entities and infrastructure. The Task Force encourages the Rebuild Iowa Advisory Commission to balance the immediate needs for rebuilding to include the beginning of the investments required to effectively mitigate future damage and maintain effective policy in Iowa’s watersheds. The significance of the damage seen in Iowa from the tornadoes, storms, and floods of 2008 include the loss of eighteen Iowans in disaster-related events. This alone should inspire investment in mitigation efforts for all hazards. Much of the damage resulting from the disasters can be tied to floodplain management and hazard mitigation, pointing the way toward enhanced efforts and new initiatives to safeguard lives, property, and communities’ economic health. Even so, it must be recognized that the weather events throughout last winter and spring added impetus to the rains and storms that ultimately resulted in record flooding. Some perspective must be maintained as planning progresses and significant investments in mitigation are considered to meet a specific level of safety and protection from future threats. The Task Force identified a number of issues, and four were agreed-upon as those with the highest priority to be addressed by the Task Force through a set of recommendations. Supplemental Information to the August 2008

Minimal analytical characterisation of engineered nanomaterials need for hazard assessment in biological matrices

The safe and responsible development of engineered nanomaterials (ENM), nanotechnology-based materials and products, together with the definition of regulatory measures and implementation of "nano"-legislation in Europe require a widely supported scientific basis and sufficient high quality data upon which to base decisions. At the very core of such a scientific basis is a general agreement on key issues related to risk assessment of ENMs which encompass the key parameters to characterise ENMs, appropriate methods of analysis and best approach to express the effect of ENMs in widely accepted dose response toxicity tests. The following major conclusions were drawn: Due to high batch variability of ENMs characteristics of commercially available and to a lesser degree laboratory made ENMs it is not possible to make general statements regarding the toxicity resulting from exposure to ENMs. 1) Concomitant with using the OECD priority list of ENMs, other criteria for selection of ENMs like relevance for mechanistic (scientific) studies or risk assessment-based studies, widespread availability (and thus high expected volumes of use) or consumer concern (route of consumer exposure depending on application) could be helpful. The OECD priority list is focussing on validity of OECD tests. Therefore source material will be first in scope for testing. However for risk assessment it is much more relevant to have toxicity data from material as present in products/matrices to which men and environment are be exposed. 2) For most, if not all characteristics of ENMs, standardized methods analytical methods, though not necessarily validated, are available. Generally these methods are only able to determine one single characteristic and some of them can be rather expensive. Practically, it is currently not feasible to fully characterise ENMs. Many techniques that are available to measure the same nanomaterial characteristic produce contrasting results (e.g. reported sizes of ENMs). It was recommended that at least two complementary techniques should be employed to determine a metric of ENMs. The first great challenge is to prioritise metrics which are relevant in the assessment of biological dose response relations and to develop analytical methods for characterising ENMs in biological matrices. It was generally agreed that one metric is not sufficient to describe fully ENMs. 3) Characterisation of ENMs in biological matrices starts with sample preparation. It was concluded that there currently is no standard approach/protocol for sample preparation to control agglomeration/aggregation and (re)dispersion. It was recommended harmonization should be initiated and that exchange of protocols should take place. The precise methods used to disperse ENMs should be specifically, yet succinctly described within the experimental section of a publication. 4) ENMs need to be characterised in the matrix as it is presented to the test system (in vitro/ in vivo). 5) Alternative approaches (e.g. biological or in silico systems) for the characterisation of ENMS are simply not possible with the current knowledge. Contributors: Iseult Lynch, Hans Marvin, Kenneth Dawson, Markus Berges, Diane Braguer, Hugh J. Byrne, Alan Casey, Gordon Chambers, Martin Clift, Giuliano Elia1, Teresa F. Fernandes, Lise Fjellsbø, Peter Hatto, Lucienne Juillerat, Christoph Klein, Wolfgang Kreyling, Carmen Nickel1, and Vicki Stone.

Geomorphological method in the elaboration of hazard maps for flash-floods in the municipality of Jucuarán (El Salvador)

This work deals with the elaboration of flood hazard maps. These maps reflect the areas prone to floods based on the effects of Hurricane Mitch in the Municipality of Jucuarán of El Salvador. Stream channels located in the coastal range in the SE of El Salvador flow into the Pacific Ocean and generate alluvial fans. Communities often inhabit these fans can be affected by floods. The geomorphology of these stream basins is associated with small areas, steep slopes, well developed regolite and extensive deforestation. These features play a key role in the generation of flash-floods. This zone lacks comprehensive rainfall data and gauging stations. The most detailed topographic maps are on a scale of 1:25 000. Given that the scale was not sufficiently detailed, we used aerial photographs enlarged to the scale of 1:8000. The effects of Hurricane Mitch mapped on these photographs were regarded as the reference event. Flood maps have a dual purpose (1) community emergency plans, (2) regional land use planning carried out by local authorities. The geomorphological method is based on mapping the geomorphological evidence (alluvial fans, preferential stream channels, erosion and sedimentation, man-made terraces). Following the interpretation of the photographs this information was validated on the field and complemented by eyewitness reports such as the height of water and flow typology. In addition, community workshops were organized to obtain information about the evolution and the impact of the phenomena. The superimposition of this information enables us to obtain a comprehensive geomorphological map. Another aim of the study was the calculation of the peak discharge using the Manning and the paleohydraulic methods and estimates based on geomorphologic criterion. The results were compared with those obtained using the rational method. Significant differences in the order of magnitude of the calculated discharges were noted. The rational method underestimated the results owing to short and discontinuous periods of rainfall data with the result that probabilistic equations cannot be applied. The Manning method yields a wide range of results because of its dependence on the roughness coefficient. The paleohydraulic method yielded higher values than the rational and Manning methods. However, it should be pointed out that it is possible that bigger boulders could have been moved had they existed. These discharge values are lower than those obtained by the geomorphological estimates, i.e. much closer to reality. The flood hazard maps were derived from the comprehensive geomorphological map. Three categories of hazard were established (very high, high and moderate) using flood energy, water height and velocity flow deduced from geomorphological and eyewitness reports.

Minimal analytical characterization of engineered nanomaterials needed for hazard assessment in biological matrices.

Abstract This paper presents the outcomes from a workshop of the European Network on the Health and Environmental Impact of Nanomaterials (NanoImpactNet). During the workshop, 45 experts in the field of safety assessment of engineered nanomaterials addressed the need to systematically study sets of engineered nanomaterials with specific metrics to generate a data set which would allow the establishment of dose-response relations. The group concluded that international cooperation and worldwide standardization of terminology, reference materials and protocols are needed to make progress in establishing lists of essential metrics. High quality data necessitates the development of harmonized study approaches and adequate reporting of data. Priority metrics can only be based on well-characterized dose-response relations derived from the systematic study of the bio-kinetics and bio-interactions of nanomaterials at both organism and (sub)-cellular levels. In addition, increased effort is needed to develop and validate analytical methods to determine these metrics in a complex matrix.