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131.
In the present paper we analyse the series of extreme events in geoelectrical signals recorded at the monitoring station Tito located in a seismic area of southern Italy. Applying an objective criterion to estimate the probability of occurrence of extreme events in the time series (Cuomo et al., 1996; Cuomo et al., 1997), we found a correlation between the geoelectrical anomalies and earthquakes in the area monitored during the period of recording.  相似文献   
132.
Local soil failure before general slope failure   总被引:1,自引:0,他引:1  
Slopes are generally characterized by non-uniform stress field. Additional stresses induced by changes in boundary conditions can emphasize local differences in the stress level. As a consequence, every failure process is, at first, local, with formation of plastic zones, then general. This is the subject of this paper, which concerns clay slopes, whose failure generally implies formation of a shear zone. A special consideration is addressed to the simple and special case of infinite slope which is also featured by transition from local to general failure, even if stress conditions are uniform along the potential failure plane.  相似文献   
133.
Measuring multifractality in seismic sequences   总被引:6,自引:0,他引:6  
We investigated the multifractal structure of the interevent times between successive earthquakes that occurred in Umbria-Marche, which is one of the most seismically active areas of central Italy. We used the Multifractal Detrended Fluctuation Analysis (MF-DFA), which permits detection of multifractality in nonstationary series. Analyzing the time evolution of the multifractal behaviour of the seismic sequence, a loss of multifractality during the aftershocks is revealed.  相似文献   
134.
Small-scale livelihood projects are widely used in forest conservation and Reducing Emissions from Deforestation and Degradation (REDD)+ initiatives; however, there is limited information on how effective these projects are at delivering livelihood and conservation benefits. We explored local perceptions of the effectiveness of small-scale livelihood projects in delivering livelihood and conservation benefits in eastern Madagascar. Our results suggest that small-scale livelihood projects vary greatly in their ability to deliver livelihood benefits, and that the type of livelihood project (e.g., agriculture, beekeeping, fish farming, or livestock production) has a significant impact on which livelihood benefits are delivered. Many small-scale livelihood projects, regardless of project type, are perceived to contribute to forest conservation efforts. Our study highlights that small-scale livelihood projects have the potential to contribute to both improved livelihoods and enhanced forest conservation, but also illustrates the need for more information on the factors that lead to project success.  相似文献   
135.
In many areas of the world, slopes covered by shallow unsaturated non-plastic soil layers experience rainfall-induced landslides causing heavy damage and casualties every year. Landslide occurrence depends on the amount of water infiltrated and stored. Among the contributing factors are the hydraulic conditions at the lowermost boundary, a feature that is often disregarded. The paper focuses on this topic, presenting the results of some laboratory and numerical experiments on ash-pumice interfaces. A strategy is then proposed for selecting the lowermost boundary condition, and some studies are carried out to compare the results obtained with the proposed solution and other more popular ones.  相似文献   
136.
The level of parental investment for larval nutrition may determine the life cycle in marine invertebrate species laying egg masses or capsules, where the food available for enclosed individuals would determine time and developmental stage of hatching. Most species show a unique type of larval development. However, few species are poecilogonous and combine more than one development type. Poecilogony, although scarcely studied, allows comparing different patterns of parental reproductive investment, without the phylogenetic effect of the species ancestral modes of development (phylogenetic inertia), to help to understand the factors determining life strategy evolution in marine invertebrates. The poecilogonous polychaete worm Boccardia wellingtonensis encapsulates and incubates its offspring, which then hatches as either planktotrophic larvae or benthic juveniles; while Boccardia chilensis shows a non-poecilogonous reproductive type, producing only planktotrophic larvae. In this work, we estimated the bioenergetic and biochemical composition of brooding and non-brooding females of B. wellingtonensis and B. chilensis to compare the costs of reproduction in these two species. Results showed that glucose, protein, lipid, and energy content were significantly higher in non-brooding than in brooding females of B. wellingtonensis; but also contained significantly more glucose, protein, and lipid than females of B. chilensis (in absolute and relative dry weight values). The poecilogonous species showed higher energy content previous to laying offspring. Our results support the idea that the evolution of a certain reproductive and life history traits in marine invertebrates is related to adaptations in the female's reproductive investment.  相似文献   
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