1,720,977 research outputs found
Impacts of global environmental changes on water: challenges for sustainable development
No full textThis research aims at understanding how human driven global environmental changes in terms of climate and land use are expected to affect the spatial and temporal distribution of water resources. The main questions that thesis asks are: (1) how global climate and land use change are expected to impact the spatial and temporal distribution of the water resources. (2) How human activities like hydropower and agricultural production are likely to be impacted by global environmental changes. (3) How different socio-environmental systems could be adapted to the changing conditions. The thesis is organized in a set of studies aimed at estimating the main practical consequences in terms of hydropower and agricultural production at different geographical scale. It does so selecting the most appropriate tool, from the two main categories of statistical analysis and physical modeling, for each of the specific case studies. A statistical model is utilized to assess the sensitivity of the global hydropower generation to variations in climate. A biosphere model integrated with a routing scheme is utilized to assess the impacts of climate and land use change on the hydrology of the Tapajos river basin, a portion of the Brazilian Amazon. A hydro-energy model was used to assess the possible implications in case of hydropower development in the river system. A crop model was used to analyze the expected impacts to the agricultural productivity in the upper part of the Tapajos basin, one of the most important areas for this economic sector in Brazil. Results show how the global hydropower system is expected to be vulnerable to global changes with specific magnitudes linked to the spatial distribution of climate change and the specific characteristics of the power plants. The Tapajos river basin hydrology is expected to be seriously impacted by climate change, mainly through a delay in the beginning of the rainy season and a reduction of its duration. Land use change, in the specific case deforestation, is expected to partially invert the decreasing trends in river discharge caused by climate change, but causing a consistent increase in flow variability. Moreover, the crop analysis confirmed the expected negative climate change impacts on the agricultural sector in the upper part of the basin, creating the basis for a possible demand for irrigation: an adaptation strategy destined at increasing the anthropogenic pressure on the water resources. The project aims at providing policy makers with a better understanding of the expected future impacts and enhances long-term adaptation strategies. The global hydropower analysis gives an idea of the patterns of vulnerability of this system of production. The basin scale analysis shows how the river flow could be modified by the combined effects of climate, land use change and alternative uses water demand. This confirms that an increasing level of uncertainty should be taken into consideration in case of infrastructural development of the area.
This thesis provides a significant contribution to the debate about uncertainty and stationarity in water management. It proves, providing practical examples, how different socio-economic and ecological systems at different geographical scale are interconnected: the dynamics influencing one system affect, directly or indirectly, the connected systems causing a cascade effect
Spatial assessment of water use efficiency (SDG Indicator 6.4.1) for regional policy support
Get PDFCountries are facing the challenge of identifying the most effective implementation strategies and measures for achieving Sustainable Development Goals (SDG) and their specific targets. The standard procedure proposed by international organizations consists of a set of indicators (one or more per target) assessed at country level. However, such country scale assessments have only limited potential for regional or national policymaking, because of aggregation and averaging effects, which limit the identification of phenomena, their causal relationships, and their spatial-temporal dynamics. The need thus emerges for defining assessment procedures that go beyond national level aggregation and zoom into local phenomena, while maintaining a link with the approach adopted at the global level for monitoring and reporting the progress toward the meeting of the SDGs. SDG 6 focuses on water resources and aims at achieving safe water and sanitation for all, which are essential to human health, environmental sustainability, and economic prosperity. SDG 6 is evidently interconnected with several other SDGs, and in particular with those focused on food production (SDG2) and other socio-economic activities using water as a production factor. This paper proposes an approach to assess SDG 6, based upon freely available global data sets. The methodology is suitable for both reporting at international level in accordance with approved guidelines proposed by custodian agencies and -more importantly-analyzing the spatial features of the phenomena related to the SDGs and their targets, producing information useful to support effective sustainability oriented policies. The proposed approach is demonstrated for the assessment of the indicator 6.4.1 (Change in water use efficiency) in South and South-East Asia, with the ambition to provide operational solutions timely applicable at the global level by exploiting the ever-increasing availability of spatial information deriving from ongoing exercises in the field of global change. This will allow identifying current and emerging water management issues, such as the areas where strategies are required to increase the availability of water resources, or those necessitating transboundary strategies. Scenario analysis driven by the IPCC Shared Socioeconomic Pathways is developed to explore policy and technological solutions across the nexus between water management and agriculture
Policy-relevant assessment method of socio-economic impacts of flooding: an Italian case study.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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