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Dynamic risk processes, which involve interactions at the hazard and risk levels, have yet to be clearly understood and properly integrated into probabilistic risk assessment. While much attention has been given to this aspect lately, most studies remain limited to a small number of site-specific multi-risk scenarios. We present a generic probabilistic framework based on the sequential Monte Carlo Method to implement coinciding events and triggered chains of events (using a variant of a Markov chain), as well as time-variant vulnerability and exposure. We consider generic perils based on analogies with real ones, natural and man-made. Each simulated time series corresponds to one risk scenario, and the analysis of multiple time series allows for the probabilistic assessment of losses and for the recognition of more or less probable risk paths, including extremes or low-probability–high-consequences chains of events. We find that extreme events can be captured by adding more knowledge on potential interaction processes using in a brick-by-brick approach. We introduce the concept of risk migration matrix to evaluate how multi-risk participates to the emergence of extremes, and we show that risk migration (i.e., clustering of losses) and risk amplification (i.e., loss amplification at higher losses) are the two main causes for their occurrence.  相似文献   

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Eclogites were relatively recently found in the Belomorian Mobile Belt (BMB) (Volodichev et al., 2004; Shchipanskii et al., 2005; Konilov et al., 2004). The very first isotopic dates (Volodichev et al., 2004; Mints et al., 2010) were obtained for these rocks in the northwestern (in the Salma and Kuru-Vaara areas) and central (Gridino area) portions of BMB and corresponded to the Archean: approximately 2.72–2.87 Ga. Because no crustal eclogites older that 2.0 Ga (Möller et al., 1995) had been known before these dates were obtained, these eclogites were regarded as unique. It is commonly believed that no crustal eclogites could be formed in the Archean because the crust was then relatively thin (Kröner, 2010), and hence, the find of crustal eclogites of Archean age in BMB called for a fundamental revision of geodynamic reconstructions of the crustal evolution and was one of the main arguments invoked to support the hypothesis that currently operating geodynamic mechanisms of plate tectonic can be extrapolated to the Early Precambrian (Rozen et al., 2008). However, these finds were practically immediately followed by serious doubts that the primary estimates of the timing of the eclogite metamorphism in the Belomorian Belt may be incorrect (Mitrofanov et al., 2009; and others).  相似文献   

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In the United States, contemporary anti-science education coalitions are increasingly linking climate change and evolution using “teach the controversy” campaigns. Awareness of this political phenomena raises questions about the extent to which portrayals of global warming predictions as mere knowledge claims undermine efforts to increase public understanding of scientific consensus about global warming. This paper uses a critical political ecology framework to explore the problematization of climate change consensus located and performed across discourses of secondary science teaching and learning. Theories of resistance are used to analyze teachers’ everyday experiences with classroom pushback about climate change. Data collection included key informant interviews with state science education stakeholders and on-line survey of 5th–12th grade science teachers in Oklahoma, USA. The article synthesizes the situated discourses of Oklahoma science teachers’ and their attitudes about teaching climate change in the face of public controversy. Our analysis demonstrates teachers marginalized by anti-science controversies but engaged in everyday acts of resistance to political, ideological, and religious norms. Most notably, science teachers re-purpose “teach the controversy” frames as a way to introduce climate change where it might not otherwise be included. We argue that, contextualized within a history of contestation over the teaching of evolution, the practice of teaching ‘both sides’ is an important boundary ordering device that bridges convinced and skeptical discourses in the classroom. This research informs new roles and possibilities for science education on global environmental change by reminding climate scientists, educators, and policy advocates that all climate change knowledge is coproduced.  相似文献   

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Catastrophic debris flows hit many areas in the world. Surprisingly, the features of the materials which are involved are often very similar as well as the causes of rupture and the mechanics of resulting movement. A continuous exchange of ideas among people involved in studies and investigations could be highly beneficial in the setting up of reliable criteria for risk mitigation.  相似文献   

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There are several methods to test the hypothesis of complete spatial randomness of point patterns. This work involves a new geometrical-based strategy to detect spatial arrangements, which takes into account both Euclidean and angular distances, defining a triangle-based network. An asymptotic test based on the Kolmogorov–Smirnov statistic is proposed to accommodate this situation. To assess the usefulness of this method (Stat-Geo), simulations based on Monte Carlo procedures, conducted using SPLUS, give satisfactory results with a high degree of accuracy. As expected, the new technique proposed in this paper, performs better than traditional ones like distance-based or angle-based, since more information (combining distance and angle) is introduced in the decision-making system. This approach is a very simple way to offer high efficiency results for a low computational cost. Furthermore, this alternative method allows barycentric interpolation of the unsampled points into a two-dimensional simplex (triangular) framework.  相似文献   

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In 1950, D. Korzhinskii hypothesized that minerals in metamorphic reactions can be in local equilibrium. Proceeding from this idea, G. Fisher and R. Joesten later developed a realistic model of metamorphism kinetics. The model included diffusive mass transport in intergranular fluid controlled by the concentrations of components and chemical potential gradients, local-equilibrium reactions between minerals and pore fluid, mass balance of components, etc. The Korzhinskii–Fisher–Joesten model can provide clues to the duration of metamorphic events as inferred from mineral chemistry, free energy of phases, and rock textures and structures. The respective modeling of metamorphic reactions, with regard to spatial distribution of mineral grains, has implications for the transport and balance of chemical components. The balance of components (except volatiles) is restricted to domains of hundredth fractions of a cubic millimeter to several cubic meters. This may be the minimum size of an elementary domain in which minerals are in local equilibrium.  相似文献   

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The stable isotopic analyses (δ18O and δ13C) of a coralFavia speciosa spanning forty two years (1948–89 A.D.), collected from the Pirotan island (22.6°N, 70°E) in the Gulf of Kutch have been carried out to assess its potential for retrieving past environmental changes in this region. It is seen that the summer (minima) δ18O variations in the coral CaCO3 are negatively correlated with seasonal (summer) monsoon rainfall in the adjoining region of Kutch and Saurashtra and a qualitative reconstruction of historical rainfall variations in this region can be obtained by analyzing the δ18O in this species of coral. The observed mean seasonal range of δ18O variations is 0.34 ±0.17‰ (n = 42), whereas the expected range calculated (from available SST and measured δ18O of sea water) is ∼ 1.1 ±0.15‰ The difference is due to the coarse resolution of sampling, which can be corrected. The seasonal range in δ13C is ∼ l‰ and is explained by changes in: a) the light intensity related to the cloudiness during monsoons and b) phytoplankton productivity.  相似文献   

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Soil erosion by water is recognised as a worldwide land degradation issue, particularly in arid and semi-arid regions. The aim of this study is to apply the powerful capabilities of advanced remote sensing and geographic information system techniques to identify the areas at risk to water erosion. This study presents the assessment of water erosion in mountainous areas (eastern Aures, Algeria) based on three main factors: the friability of the bedrock, degree of slope and density of vegetation cover. Alsat1 image was used to produce land use and vegetation (NDVI) maps. Digital elevation model was used in constructing the slope gradient map. The erosion risk map was obtained by the combination of indices assigned to thematic layers following multicriteria decision rules. Water erosion was generally not concerning in the eastern Aures (slight risk = 33 %, moderate risk = 44 % of the area). This simple–qualitative approach gave good results for assessing soil erosion equally to quantitative methods since 89.55 % of field verifications were accurate. The non-alarming state and the low rate of severe and extremely severe risk to erosion are due to (1) the low steep slopes, (2) the good quality of vegetation (forests with thick undergrowth), and which are occurring on (3) resistant materials of the substratum, and (4) the low human pressure. Results of this study, which may be conducted with reasonable costs and accuracy over large areas, are of significant help in prioritising areas in decision making and sustainable planning.  相似文献   

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News and Notes

Penrose Conference — 2011 on Deformation Localization in Rocks: New Advances — Manish A. Mamtani (IIT, Kharagpur; Email: mamtani@gg.iitkgp.ernet.in)  相似文献   

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Occurrence of drought, as an inevitable natural climate feature, cannot be ceased while happening. However, costs of the consequences could be alleviated using mature scientific integrated approaches. To reduce the amount of damage, it is required to provide “Contingency” and “Mitigation” action plans. For this reason, development of efficient operating instructions for various regions based on weather conditions and field studies is needed as well as having a sophisticated understanding of socioeconomic situations. This paper describes an approach to provide the first national agricultural drought risk management plan for a river basin in Iran country as a pilot. The study lasted for 3 years as a national technical research project for the “soil conservation and watershed management research institute.” To reach the objectives, besides holding workshops and specialized think-tank meetings, field researches were done. Based on the socioeconomic data sources in the basin and the results of meetings by participation of local managers and residents, the final plan was developed. Moreover, in order to carry out this research, different climatic, agricultural and local information were collected in the watershed. In the next steps, potential risks and vulnerabilities of various agricultural sectors due to the hazard were evaluated. In this study, a nine-step approach to develop an agricultural drought risk management plan proposing different scientific–managerial phases based on the latest experts’ opinions, released international scientific best practices, and existing conditions governing the region was followed. With respect to the average income of US$ one million from agriculture and animal husbandry in the river basin, total drought loss varies from US$ 86,000 to US$ 258,000 for a range of light to very intense drought conditions, respectively. The setup of these nine executive phases defined monitoring, forecasting, and warning steps in working teams and managed the subprograms in partnership with stakeholders and decision-makers to mitigate the rate of drought damage from 30 to 47% (depending on the severity of the drought condition).

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