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981.
A framework is proposed to characterize and forecast the displacement trends of slow-moving landslides, defined as the reactivation stage of phenomena in rocks or fine-grained soils, with movements localized along one or several existing shear surfaces. The framework is developed based on a thorough analysis of the scientific literature and with reference to significant reported case studies for which a consistent dataset of continuous displacement measurements is available. Three distinct trends of movement are defined to characterize the kinematic behavior of the active stages of slow-moving landslides in a velocity-time plot: a linear trend-type I, which is appropriate for stationary phenomena; a convex shaped trend-type II, which is associated with rapid increases in pore water pressure due to rainfall, followed by a slow decrease in the groundwater level with time; and a concave shaped trend-type III, which denotes a non-stationary process related to the presence of new boundary conditions such as those associated with the development of a newly formed local slip surface that connects with the main existing slip surface. Within the proposed framework, a model is developed to forecast future displacements for active stages of trend-type II based on displacement measurements at the beginning of the stage. The proposed model is validated by application to two case studies.  相似文献   
982.
Although the high diversity of plant species in the rupestrian fields has been primarily attributed to the existence of a set of distinct habitats, few studies support this assertion. The present study aimed to further investigate the relationship between physical and chemical attributes of soils with the diversity of plant species in this unique ecosystem. The rupestrian field is a unique vegetation formation that covers some of the southeastern Brazilian mountains in the transition of the Atlantic rain forest and the Cerrado (savanna). Different habitats occur according to soil characteristics (e.g., presence of rocks, sand, fertility, hydrology, etc.). These attributes ultimately influence the vegetation that is highly adapted to the harsh edaphic and climatic mountain conditions. Five distinct habitats were studied by us: rocky outcrops, peat bogs, sandy bogs, quartz gravelfields, and "cerrado" (savanna). A floristic survey indicated that four families are found at greater frequency: Poaceae, Asteraceae, Cyperaceae, and Leguminosae. The greatest diversity of plant species was found in the rocky outcrops habitat, followed by cerrado, peat bog, quartz gravel grassland, and sandy bogs, respectively. The main difference in the floristic composition among these habitats was related to the dominant species. Trachypogon spicatus (Poaceae) was the most dominant species in the rocky outcrops, Axonopus siccus (Poaceae) in the peat bogs, Lagenocarpus rigidus (Cyperaceae) in the sandy bogs, Schizachyrium tenerum (Poaceae) in the cerrado, while Vellozia sp. 8 (Velloziaceae) dominated the vegetation in the quartz gravel grassland. This study demonstrated that physical and chemical soil properties strongly related the diversity of plant species occurring in the different habitats of rupestrian fields.  相似文献   
983.
The outsourcing and offshoring of services to developing countries has created new opportunities for economic development for countries in the global South. This paper looks at the scope for agency of local institutional actors in the investment attraction of business process outsourcing companies. Drawing on empirical work from the Philippines, an analysis of the process of integrating lower‐tier cities into global service production networks is presented. Specifically, the roles of local institutional actors in facilitating FDI attraction and strategically coupling local assets with the needs of multinational service corporations are discussed. Two contrasting cases, the cities of Baguio and Bacolod, show that considerable scope for intervention rests with local institutional actors. The findings have implications for policymaking and research concerned with the newest phase of outsourcing and offshoring in developing countries.  相似文献   
984.
The eutrophication history of a tropical water supply reservoir in Brazil   总被引:1,自引:0,他引:1  
Guarapiranga Reservoir is the second most important public water supply in São Paulo, Brazil and has been eutrophic for several decades. We inferred the major ecological shifts for the period 1919–2010 related to multiple stressors (forest flooding, hydrological change, use of algicide and eutrophication), using geochemistry (TOC, TN, TP, C/N, δ15N, δ13C) and diatom assemblages in a short (75-cm) sediment core. Thirty-two diatom species were abundant in the core and stratigraphically constrained incremental sum of squares analysis enabled identification of three diatom zones and four subzones, i.e. depths at which marked changes in species composition occurred. Early diatom assemblages were dominated by benthic, oligotrophic taxa, mainly Eunotia, influenced by flooded vegetation after dam construction. A shift to dominance by a planktonic species (Eunotia tukanorum) occurred ca. 1932, during the period of initial physical disturbance and early use of the water body as a public water supply. Diatoms and geochemical variables show that the reservoir was oligotrophic from ~1919 to 1947. Eutrophication began ~1975 and by the early 1980s the reservoir had become eutrophic, in response to an explosive increase in human population in the watershed. Severe cultural eutrophication has persisted since ~1990. Higher concentrations of copper in the sediments, beginning in 1991, reflect the increased use of copper sulfate to control cyanobacteria blooms and provide a chronological marker. Higher δ15N values in recent sediments indicate greater sewage inputs and low C/N values reflect the predominant contribution of algae to sediment organic matter. Eutrophic taxa Cyclotella meneghiniana and Nitzschia sp. dominate recent diatom assemblages, along with Aulacoseira granulata, a species that is tolerant of copper sulfate. Diatom assemblages reflect multiple stressors, however, geochemical information provides a better understanding of the early phase of the reservoir. Paleolimnologically documented trophic state changes in this important drinking water supply are largely attributable to increased urbanization of the drainage basin and inputs of sewage. Management efforts should focus on mitigating this nutrient source.  相似文献   
985.
Stakeholder engagement has become increasingly important in research programs focusing on climate change impact on ecosystem services. Communication between researchers and stakeholders, however, is often impaired by linguistic barriers, different priorities, and time constraints. This article examines the organizational aspects of science–stakeholder interactions, focusing on examples from the Swedish forestry sector. The study highlights the need articulated by the Swedish forestry sector for access to scientific knowledge, and we discuss how to present research findings in formats suitable to serve as decision support. Clear communication about common goals, expectations, resources, and time frames is needed in order to reduce the risk of stakeholder fatigue.  相似文献   
986.
A spectral linear-mixing model using Landsat ETM+ imagery was undertaken to estimate fraction images of green vegetation, soil and shade in an indigenous land area in the state of Mato Grosso in the central-western region of Brazil. The fraction images were used to classify different types of land use and vegetation cover. The fraction images were classified by the following two methods: (a) application of a segmentation based on the region-growing technique; and (b) grouping of the regions segmented using the per-region unsupervised classifier named ISOSEG. Adopting a 75% threshold, ISOSEG generated 44 clusters that were grouped into eight land-use and vegetation-cover classes. The mapping achieved an average accuracy of 83%, showing that the methodology is efficient in mapping areas of great land-use and vegetation-cover diversity, such as that found in the Brazilian cerrado (savanna).  相似文献   
987.
The results of palaeomagnetic, rock magnetic, and microscopic study of Early Paleozoic metabasites and granulites from the Orlica?nie?nik Dome (OSD, Sudetes) have been combined with geochronological data. In the eastern part of the OSD (?nie?nik Massif, SM) ferrimagnetic pyrrhotite is prevalent, accompanied by various amounts of Fe-oxides. In the western part of the OSD (Orlica-Bystrzyca Massif, OBM) Fe-oxides dominate. All magnetic minerals originated during hydrothermal and weathering processes. The palaeomagnetic study revealed the presence of three secondary components of natural remanence: Late Carboniferous, Late Permian, and Mesozoic. Two Paleozoic components are related to volcanic activity in the Sudetes. They are carried by pyrrhotite and Fe-oxides and were isolated only in SM rocks. The Mesozoic component was determined in both parts of the OSD and is carried by Fe-oxides. It covers a time span, from ~160 to ~40 Ma, corresponding to a long period of alteration.  相似文献   
988.
Although there have been numerous studies of the meanings ascribed to terrestrial places, their applicability or otherwise to coastal and marine places has received limited attention. Through the process of photo-elicitation, the meanings ascribed to a remote coastal camping environment are examined, with the coastline of Ningaloo Marine Park in north-western Australia the focus for this study. Thirty participants were provided with digital cameras and the ascribed place meanings were explored when their photographs were discussed in subsequent in-depth interviews. Key meanings related to the physical environment providing opportunities for escape, participating in multiple marine-based activities, bonding with family and like-minded people, and offering a rewarding experience that makes everybody happy. This emergent meaning of ‘everybody's happy’ progresses the understanding of the affective elements of place, especially those realised by families and groups of friends. The paper traces important implications of this meaning, and provides a paradoxical perspective on isolation evident from the interviews, for managing coast-based recreation.  相似文献   
989.
Perfluorinated compounds (PFCs), widely used for their hydro-oil repellent properties, are almost non-degradable in the environment; there is scientific evidence that indicate bioaccumulation. They represent a threat to many organisms, because they are toxic and are endocrine disruptors. Scientific studies have demonstrated the presence of PFCs in blood and liver samples of fish, turtles, birds and mammals of marine ecosystems in different geographical areas. The aim of this study was to determine the distribution of PFOS and PFOA in blood samples of the marine turtle Caretta caretta, using a minimally invasive sampling procedure. 49 blood samples of marine turtle, taken from several Italian marine turtle rescue centers, were analyzed. While PFOA was never detected, measurable concentrations of PFOS were found in 15 blood samples; the values show a range from 1.14 ng/g to 28.51 ng/g (wet wt.). No differences between groups of samples taken from different areas were found.  相似文献   
990.
A growing attention has been addressed to the influence of infills on the seismic behavior of Reinforced Concrete buildings, also supported by the observation of damage to infilled RC buildings after severe earthquakes (e.g. L’Aquila 2009, Lorca 2011). In this paper, a numerical investigation on the influence of infills on the seismic behavior of four different case study buildings is carried out: four- and eight-storey buildings, designed for seismic loads according to the current Italian technical code or for gravity loads only according to an obsolete technical code, are considered. Seismic capacity at two Limit States (Damage Limitation and Near Collapse) is assessed through static push-over analyses, within the N2 spectral assessment framework. Different infill configurations are considered (Bare, Uniformly Infilled, Pilotis), and a sensitivity analysis is carried out, thus evaluating the influence of main material and capacity parameters on seismic response, depending on the number of storeys and the design typology. Fragility curves are obtained, through the application of a Response Surface Method. Seismic performance is also expressed in terms of failure probability, given a reference time period.  相似文献   
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